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Some new special instructions
| author | Klaus Thoden <kthoden@mpiwg-berlin.mpg.de> |
|---|---|
| date | Fri, 02 Dec 2016 14:37:22 +0100 |
| parents | 22d6a63640c6 |
| children |
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<?xml version="1.0" encoding="utf-8"?><echo xmlns="http://www.mpiwg-berlin.mpg.de/ns/echo/1.0/" xmlns:de="http://www.mpiwg-berlin.mpg.de/ns/de/1.0/" xmlns:dcterms="http://purl.org/dc/terms" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:echo="http://www.mpiwg-berlin.mpg.de/ns/echo/1.0/" xmlns:xhtml="http://www.w3.org/1999/xhtml" xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" version="1.0RC"> <metadata> <dcterms:identifier>ECHO:M1R3K3S6.xml</dcterms:identifier> <dcterms:creator identifier="GND:118201913">Bélidor, Bernard Forest de</dcterms:creator> <dcterms:title xml:lang="fr">La science des ingenieurs dans la conduite des travaux de fortification et d' architecture civile</dcterms:title> <dcterms:date xsi:type="dcterms:W3CDTF">1754</dcterms:date> <dcterms:language xsi:type="dcterms:ISO639-3">fra</dcterms:language> <dcterms:rights>CC-BY-SA</dcterms:rights> <dcterms:license xlink:href="http://creativecommons.org/licenses/by-sa/3.0/">CC-BY-SA</dcterms:license> <dcterms:rightsHolder xlink:href="http://www.mpiwg-berlin.mpg.de">Max Planck Institute for the History of Science, Library</dcterms:rightsHolder> <parameters>despecs=1.1.2</parameters> </metadata> <text xml:lang="fr" type="free"> <div xml:id="echoid-div1" type="section" level="1" n="1"> <pb file="0001" n="1"/> <pb file="0002" n="2"/> <pb file="0003" n="3"/> <pb file="0004" n="4"/> <pb file="0005" n="5"/> <pb file="0006" n="6"/> <figure> <image file="0006-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0006-01"/> </figure> <pb file="0007" n="7"/> </div> <div xml:id="echoid-div2" type="section" level="1" n="2"> <head xml:id="echoid-head1" xml:space="preserve"><emph style="red">LA SCIENCE</emph> <lb/>DES <lb/><emph style="red">INGENIEURS</emph> <lb/>DANS LA <lb/>CONDUITE DES TRAVAUX <lb/><emph style="red">DE FORTIFICATION</emph> <lb/>ET <lb/>D’ARCHITECTURE CIVILE, <lb/><emph style="red">DEDIÉE AU ROY.</emph></head> <p style="it"> <s xml:id="echoid-s1" xml:space="preserve">Par <emph style="red">Mr. BELIDOR,</emph> Commiſſaire Ordinaire de l’Artillerie, <lb/>Profeſſeur Royal des Mathématiques aux Ecôles du même Corps, <lb/>Membre des Académies Royales des Sciences d’Angleterre & </s> <s xml:id="echoid-s2" xml:space="preserve">de <lb/>Pruſſe, & </s> <s xml:id="echoid-s3" xml:space="preserve">Correſpondant de celle de Paris.</s> <s xml:id="echoid-s4" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div3" type="section" level="1" n="3"> <head xml:id="echoid-head2" xml:space="preserve"> <emph style="red">NOUVELLE EDITION.</emph> </head> <figure> <image file="0007-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0007-01"/> </figure> </div> <div xml:id="echoid-div4" type="section" level="1" n="4"> <head xml:id="echoid-head3" xml:space="preserve"><emph style="red">A LA HATE,</emph> <lb/>Chez PIERRE GOSSE Junior, <lb/>Libraire de S. A. R. <lb/><emph style="red">M. DCC. LIV.</emph></head> <pb file="0008" n="8"/> <handwritten/> <handwritten/> <pb file="0009" n="9"/> <figure> <image file="0009-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0009-01"/> </figure> </div> <div xml:id="echoid-div5" type="section" level="1" n="5"> <head xml:id="echoid-head4" xml:space="preserve">AU ROY,</head> <p> <s xml:id="echoid-s5" xml:space="preserve">SIRE,</s> </p> <p style="it"> <s xml:id="echoid-s6" xml:space="preserve">L’ART de fortifier les Places étant devenu une des par-<lb/>ties la plus eſſentielle à la ſureté des Etats, j’ôſe eſperer que <lb/>VOSTRE MAJESTE’ ne deſaprouvera point la liber- <pb file="0010" n="10" rhead="EPITRE."/> té que je prens de lui preſenter ce Traité. </s> <s xml:id="echoid-s7" xml:space="preserve">Il deviendra peut-<lb/>être utile dans un tems où Elle veut rendre ſes Frontieres plus <lb/>reſpectables que jamais, moins par la crainte des entrepriſes <lb/>de ceux qui ſeroient jaloux de ſa Gloire, que pour occuper uti-<lb/>lement ſes Troupes & </s> <s xml:id="echoid-s8" xml:space="preserve">faire regner l’abondance dans ſon <lb/>Royaume par les fonds conſidér ables qui paſſent dans les mains <lb/>de ſes Sujets. </s> <s xml:id="echoid-s9" xml:space="preserve">Vos bontés pour eux, SIRE, s’étendent plus loin, <lb/>VOSTRE MAJESTE’ leur permet de percer des Ca-<lb/>naux dans pluſieurs Provinces pour faciliter le Commerce. <lb/></s> <s xml:id="echoid-s10" xml:space="preserve">L’on conſtruit de toute part des Ponts & </s> <s xml:id="echoid-s11" xml:space="preserve">des Chauſſées, qui <lb/>vont rendre les grands Chemins de la France auſſi beaux <lb/>que ceux qui ont tant fait d’honneur aux Romains, les <lb/>Sciences & </s> <s xml:id="echoid-s12" xml:space="preserve">les beaux Arts font de nouveaux progrès par les <lb/>bienfaits que VOSTRE MAJESTE’ répand ſur <lb/>ceux qui s’y attachent. </s> <s xml:id="echoid-s13" xml:space="preserve">Elle a même voulu qu’à ſon exem-<lb/>ple les Corps Militaires ſe fortifiaſſent dans les connoiſſances <lb/>les plus propres à la Guerre & </s> <s xml:id="echoid-s14" xml:space="preserve">à former les Grands-Hom-<lb/>mes; </s> <s xml:id="echoid-s15" xml:space="preserve">car, ſans parler des Camps magnifiques qu’Elle a or-<lb/>donnés, ni des avantages qu’Elle fait à la jeune Nobleſſe, <lb/>eſt-il rien de plus digne de ſa Grandeur, que les Ecôles <lb/>qu’Elle a établies pour entretenir ſon Artillerie dans un exer-<lb/>cice continuel. </s> <s xml:id="echoid-s16" xml:space="preserve">Tout marque, SIRE, la douceur de vôtre <lb/>Regne, & </s> <s xml:id="echoid-s17" xml:space="preserve">le bonheur de la Paix dont nous joüiſſons, ce <pb file="0011" n="11" rhead="EPITRE."/> qui devient l’ouvrage de vôtre Sageſſe, depuis que les plus <lb/>grands Princes de l’Europe vous ont choiſi pour l’Arbitre de <lb/>leurs intereſts, comme le ſeul dont la prudence pouvoit cal-<lb/>mer les troubles que les apparences de la Guerre avoient fait <lb/>naître. </s> <s xml:id="echoid-s18" xml:space="preserve">Que cette époque, SIRE, vous comble de Gloire, <lb/>& </s> <s xml:id="echoid-s19" xml:space="preserve">va inſpirer d’amour & </s> <s xml:id="echoid-s20" xml:space="preserve">de conſiance à toutes les Nations <lb/>qui ſeront ſures de trouver en VOSTRE MAJESTE’ <lb/>un Protecteur dont le pouvoir ne ſe fait connoître que par la <lb/>Juſtice & </s> <s xml:id="echoid-s21" xml:space="preserve">la Clemence! Que je m’eſtime heureux d’être <lb/>né ſujet d’un ſi Grand Roy, & </s> <s xml:id="echoid-s22" xml:space="preserve">de travailler pour ſon Ser-<lb/>vice! Je ſens bien que ce que je puis faire eſt au-deſſous <lb/>d’une ſi belle deſtinée; </s> <s xml:id="echoid-s23" xml:space="preserve">mais je ſçai, SIRE, que vous dai-<lb/>gnez jetter un regard favorable ſur ceux qui tâchent de <lb/>marquer leur zele pour ce qui peut avoir quelque raport <lb/>au bien de l’Etat. </s> <s xml:id="echoid-s24" xml:space="preserve">VOSTRE MAJESTE’ commen-<lb/>çoit ſon Regne Glorieux quand j’ai ébauché l’Ouvrage dont <lb/>voici le premier Volume; </s> <s xml:id="echoid-s25" xml:space="preserve">les Mathématiques qu’Elle cul-<lb/>tivoit alors me faiſoient découvrir pluſieurs voyes pour per-<lb/>fectionner les Fortifications, je n’ai ceſſé depuis de les ap-<lb/>pliquer à ce qui ſembloit n’avoir pas été traité avec aſſez <lb/>de preciſion, dans l’eſperance que j’arriverois un jour juſ-<lb/>qu’au pied du Trône de VOSTRE MAJESTE’, pour <lb/>lui offrir le fruit de mes veilles: </s> <s xml:id="echoid-s26" xml:space="preserve">la ſatisfaction d’y être par- <pb file="0012" n="12" rhead="EPITRE."/> venu va faire toute ma felicité; </s> <s xml:id="echoid-s27" xml:space="preserve">& </s> <s xml:id="echoid-s28" xml:space="preserve">les recherches les plus <lb/>pénibles n’auront rien qui n’excite de nouveau mon émula-<lb/>tion, lorſque je me rappelleray que le ſecond Volume me <lb/>procurera encore un moment ſi précieux. </s> <s xml:id="echoid-s29" xml:space="preserve">Je ſuis,</s> </p> <p> <s xml:id="echoid-s30" xml:space="preserve">SIRE,</s> </p> <p> <s xml:id="echoid-s31" xml:space="preserve">DE VOSTRE MAJESTE’,</s> </p> <p> <s xml:id="echoid-s32" xml:space="preserve">Le trés - humble, très - obéïſſant, <lb/>& </s> <s xml:id="echoid-s33" xml:space="preserve">très-fidele Sujet & </s> <s xml:id="echoid-s34" xml:space="preserve">Serviteur,</s> </p> <p> <s xml:id="echoid-s35" xml:space="preserve"><emph style="sc">Belidor</emph>.</s> <s xml:id="echoid-s36" xml:space="preserve"/> </p> <pb file="0013" n="13"/> <figure> <image file="0013-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0013-01"/> </figure> </div> <div xml:id="echoid-div6" type="section" level="1" n="6"> <head xml:id="echoid-head5" xml:space="preserve">PRÉFACE.</head> <p> <s xml:id="echoid-s37" xml:space="preserve">SI l’on conſidére tous les differens Travaux <lb/>dont les Ingenieurs ont la conduite, l’on <lb/>conviendra qu’il n’y a point de Profeſſion <lb/>qui exige plus de connoiſſance que la leur. <lb/></s> <s xml:id="echoid-s38" xml:space="preserve">Car, ſans parler de la maniere de diſpoſer les Pié-<lb/>ces de Fortification pour les rendre capables de tou-<lb/>te la deffence poſſible malgré les irrégularités des <lb/>lieux & </s> <s xml:id="echoid-s39" xml:space="preserve">la figure bizarre d’une enceinte qu’on veut <lb/>ménager, ni de tout ce qui peut les diſtinguer dans <lb/>la Guerre des Siéges, quelle foule d’objets divers ne pre-<lb/>ſente pas la conſtruction des Fortifications, qui eſt la ſeule <lb/>choſe que je me ſuis propoſée dans ce Volume. </s> <s xml:id="echoid-s40" xml:space="preserve">On ne peut <lb/>parcourir les Places Frontieres, ſans rencontrer à chaque <lb/>pas des Ouvrages d’une conſtruction particuliere: </s> <s xml:id="echoid-s41" xml:space="preserve">quel-<lb/>quefois même, ſans paſſer d’un lieu à un autre, on trouve <lb/>dans le même endroit tout ce qui peut exercer pendant <lb/>pluſieurs années les eſprits les plus laborieux & </s> <s xml:id="echoid-s42" xml:space="preserve">les plus <lb/>capables des grandes choſes. </s> <s xml:id="echoid-s43" xml:space="preserve">Quand on veut entrer dans <lb/>le détail, tout devient intereſſant, on apperçoit mille cho-<lb/>ſes eſſentielles qui échapent aux yeux de ceux qui regar-<lb/>dent les Fortifications avec indifference: </s> <s xml:id="echoid-s44" xml:space="preserve">ici il faudra tra-<lb/>vailler dans des lieux aquatiques qui préſentent cent ſortes <lb/>de difficultés à ſurmonter; </s> <s xml:id="echoid-s45" xml:space="preserve">là ce ſont des Rochers eſcar-<lb/>pés, qu’il faut ſoûmettre aux regles de l’Art; </s> <s xml:id="echoid-s46" xml:space="preserve">plus loin, <lb/>conſtruire des Digues, des Ecluſes, des Ponts, des For-<lb/>mes, des Baſſins, des Jettées, des Fanaux, des Risbans, <lb/>des Moles, & </s> <s xml:id="echoid-s47" xml:space="preserve">tant d’autres Ouvrages qui ſe font aux Places <pb file="0014" n="14" rhead="PRE’ FACE."/> Maritimes; </s> <s xml:id="echoid-s48" xml:space="preserve">ailleurs, joindre une Riviere à une autre par <lb/>des Canaux qu’il faudra peut-être faire paſſer ſur des <lb/>Montagnes, pour de-là aller traverſer quelquefois un Ma-<lb/>rais, & </s> <s xml:id="echoid-s49" xml:space="preserve">même une Riviere, ſans qu’elle devienne un obſta-<lb/>cle au chemin que le Canal doit parcourir pour faciliter <lb/>la Navigation & </s> <s xml:id="echoid-s50" xml:space="preserve">le Commerce; </s> <s xml:id="echoid-s51" xml:space="preserve">d’autre part, c’eſt un tor-<lb/>rent rapide, qu’il faut maintenir dans ſon lit, en conſtrui-<lb/>ſant des Epys pour en conſerver les bords, ou empêcher <lb/>qu’il ne détruiſe une Iſle fortifiée, ou ne s’aille répandre <lb/>dans la Campagne, & </s> <s xml:id="echoid-s52" xml:space="preserve">y cauſer de grands dommages.</s> <s xml:id="echoid-s53" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s54" xml:space="preserve">Preſentement, ſi l’on examine l’interieur des Places, l’on <lb/>y appercevra des Ouvrages de toute autre eſpece: </s> <s xml:id="echoid-s55" xml:space="preserve">ce ſe-<lb/>ront des Portes de Villes, des Ponts, des Batardeaux, <lb/>des Soûterrains, des Arſenaux, des Citernes, &</s> <s xml:id="echoid-s56" xml:space="preserve">c. </s> <s xml:id="echoid-s57" xml:space="preserve">qu’il <lb/>faut ſavoir executer. </s> <s xml:id="echoid-s58" xml:space="preserve">Enfin, l’on peut dire qu’un bon <lb/>Ingenieur eſt un homme univerſel; </s> <s xml:id="echoid-s59" xml:space="preserve">& </s> <s xml:id="echoid-s60" xml:space="preserve">que rien ne fait <lb/>plus d’honneur à la France, que d’en avoir un très-grand <lb/>nombre capable de toutes les choſes dont je viens de don-<lb/>ner un crayon.</s> <s xml:id="echoid-s61" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s62" xml:space="preserve">Quand on enviſage tout ce que comprennent les For-<lb/>tifications, n’a-t-on pas lieu d’être ſurpris qu’il n’y ait <lb/>eû juſqu’ici aucun Traité pour l’Inſtruction des jeunes gens <lb/>qui veulent prendre ce parti; </s> <s xml:id="echoid-s63" xml:space="preserve">car, je compte pour rien ceux <lb/>qu’on a mis au jour ſous le Nom de Mr. </s> <s xml:id="echoid-s64" xml:space="preserve">le Marêchal de <lb/>Vauban, pour leur donner du crédit, & </s> <s xml:id="echoid-s65" xml:space="preserve">qu’il a toûjours <lb/>deſavoué. </s> <s xml:id="echoid-s66" xml:space="preserve">D’ailleurs, ces Traités n’aprennent tout au plus <lb/>que le nom des Ouvrages, & </s> <s xml:id="echoid-s67" xml:space="preserve">à tracer ſur le Papier un front <lb/>de Poligone avec quelques dehors, dont la plûpart ſont <lb/>aſſez mal entendus: </s> <s xml:id="echoid-s68" xml:space="preserve">on n’y fait point mention de la conſ-<lb/>truction ni de tous les détails qui y ont raport. </s> <s xml:id="echoid-s69" xml:space="preserve">Ce n’eſt <lb/>pas que nous n’ayons un nombre d’habiles gens qui pour-<lb/>roient nous en donner d’excellens: </s> <s xml:id="echoid-s70" xml:space="preserve">pluſieurs ont travaillé <lb/>avec Mr. </s> <s xml:id="echoid-s71" xml:space="preserve">de Vauban; </s> <s xml:id="echoid-s72" xml:space="preserve">& </s> <s xml:id="echoid-s73" xml:space="preserve">il n’y a rien qu’on ne dût atten- <pb file="0015" n="15" rhead="PRE’ FACE."/> dre de leur capacité. </s> <s xml:id="echoid-s74" xml:space="preserve">Mais, leur ſilence eſt glorieux: </s> <s xml:id="echoid-s75" xml:space="preserve">le <lb/>Roy leur a confié les Barrieres du Royaume: </s> <s xml:id="echoid-s76" xml:space="preserve">ſans ceſſe <lb/>occupés à faire des Ouvrages nouveaux ou à maintenir les <lb/>anciens en bon état, ils ſont privés du loiſir qu’il faudroit <lb/>pour répandre leurs lumieres, & </s> <s xml:id="echoid-s77" xml:space="preserve">ſe contentent de les com-<lb/>muniquer à ceux qui travaillent ſous leurs ordres.</s> <s xml:id="echoid-s78" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s79" xml:space="preserve">Mais, ſi l’on fait réfléxion qu’on s’inſtruit fort lentement <lb/>quand on n’aprend les choſes qu’à meſure qu’elles ſe pre-<lb/>ſentent, & </s> <s xml:id="echoid-s80" xml:space="preserve">qu’il arrive rarement qu’un jeune Ingenieur <lb/>puiſſe voir dans une même Province toutes les differentes <lb/>eſpeces de Travaux qui dépendent des Fortifications; </s> <s xml:id="echoid-s81" xml:space="preserve">l’on <lb/>conviendra, que rien ne ſeroit plus utile qu’un bon Livre, <lb/>dans lequel il pût acquerir une connoiſſance generale de <lb/>toutes les parties de ſon métier: </s> <s xml:id="echoid-s82" xml:space="preserve">afin que, venant à paſſer <lb/>d’une Place à une autre, il ne ſe préſente rien dont il ne <lb/>puiſſe avoir la conduite, dès qu’il joindra la Théorie à ce <lb/>que la Pratique pourra lui apprendre. </s> <s xml:id="echoid-s83" xml:space="preserve">Il feroit alors beau-<lb/>coup plus de progrès, & </s> <s xml:id="echoid-s84" xml:space="preserve">pourroit en peu de tems ſe met-<lb/>tre en état de marcher ſur les traces des plus grands <lb/>maîtres.</s> <s xml:id="echoid-s85" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s86" xml:space="preserve">On ne peut diſconvenir, qu’un tel Livre ne fût d’une <lb/>grande utilité; </s> <s xml:id="echoid-s87" xml:space="preserve">ſans doute que l’on m’accuſera de temerité <lb/>d’avoir ôſé l’entreprendre. </s> <s xml:id="echoid-s88" xml:space="preserve">Quand je l’ai commencé, ſi j’en <lb/>avois conçû toute la conſéquence, je me ſerois bien gardé <lb/>d’y penſer; </s> <s xml:id="echoid-s89" xml:space="preserve">peut-être aurois-je pris le parti le plus ſage, <lb/>& </s> <s xml:id="echoid-s90" xml:space="preserve">me ſerois épargné par-là beaucoup de peines & </s> <s xml:id="echoid-s91" xml:space="preserve">d’in-<lb/>quiétudes. </s> <s xml:id="echoid-s92" xml:space="preserve">Mais, ce n’eſt ordinairement qu’après avoir tra-<lb/>vaillé long-tems, qu’on s’apperçoit du danger qu’il y a de <lb/>ſe faire imprimer; </s> <s xml:id="echoid-s93" xml:space="preserve">parceque, devenant plus délicat, on <lb/>ceſſe de voir ſes Ouvrages avec la même complaiſance: <lb/></s> <s xml:id="echoid-s94" xml:space="preserve">on mépriſe au bout de quatre jours ce qu’on avoit trouvé <lb/>paſſable d’abord, & </s> <s xml:id="echoid-s95" xml:space="preserve">on n’eſt jamais content de ſoy par <lb/>l’envie qu’on a de mieux faire.</s> <s xml:id="echoid-s96" xml:space="preserve"/> </p> <pb file="0016" n="16" rhead="PRE’FACE."/> <p> <s xml:id="echoid-s97" xml:space="preserve">Il y a 13 ou 14 ans que j’ai ébauché celui-ci, ſans avoir <lb/>pû me perſuader qu’il méritât d’être mis au jour; </s> <s xml:id="echoid-s98" xml:space="preserve">& </s> <s xml:id="echoid-s99" xml:space="preserve">peut-<lb/>être ne ſeroit-il pas ſorti de mon Cabinet, ſi j’en avois été <lb/>entierement le maître. </s> <s xml:id="echoid-s100" xml:space="preserve">Je n’affecte point une fauſſe mo-<lb/>deſtie; </s> <s xml:id="echoid-s101" xml:space="preserve">les perſonnes aux lumieres deſquelles j’ai ſoûmis <lb/>mes écrits rendront juſtice à la ſincerité de mes ſentimens: <lb/></s> <s xml:id="echoid-s102" xml:space="preserve">la gloire d’avoir fait un Livre ne s’eſt jamais preſentée à <lb/>mon eſprit d’une maniere aſſez riante, pour me ſentir flatté <lb/>de la qualité d’Auteur. </s> <s xml:id="echoid-s103" xml:space="preserve">Je n’ai jamais perdu de vûë la cen-<lb/>ſure à laquelle j’allois m’expoſer, & </s> <s xml:id="echoid-s104" xml:space="preserve">cette penſée m’a même <lb/>ſouvent intimidé: </s> <s xml:id="echoid-s105" xml:space="preserve">cependant, j’ai fait enſorte d’en tirer <lb/>avantage, en conſidérant la rigueur du Public comme un <lb/>motif excellent pour me rendre circonſpect. </s> <s xml:id="echoid-s106" xml:space="preserve">Tout le mon-<lb/>de eſt d’accord, que ce n’eſt que depuis qu’on l’a regardé <lb/>comme un Juge inexorable, que l’émulation des Gens de <lb/>Lettres s’eſt accrûë, & </s> <s xml:id="echoid-s107" xml:space="preserve">que les Bibliotheques ſe ſont groſ-<lb/>ſies d’un grand nombre de Livres en toute ſorte de genre, <lb/>qui ne ſeroient peut-être pas ſi achevés, ſi ceux qui les <lb/>ont produits n’avoient apprehendé le ridicule que les gens <lb/>de bon goût ont coûtume de donner à tout ce qui porte <lb/>un caractere de médiocrité. </s> <s xml:id="echoid-s108" xml:space="preserve">Il eſt vrai qu’il y a des ma-<lb/>tieres ſi abondantes par elles-mêmes, que, pour peu qu’on <lb/>les traite avec méthode, on peut ſe tirer plus heureuſe-<lb/>ment d’affaire: </s> <s xml:id="echoid-s109" xml:space="preserve">celles dont je parle ſont de cette nature; </s> <s xml:id="echoid-s110" xml:space="preserve"><lb/>&</s> <s xml:id="echoid-s111" xml:space="preserve">, pour juger du Plan general que je me ſuis propoſé, <lb/>en voici la Diſpoſition.</s> <s xml:id="echoid-s112" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s113" xml:space="preserve">Il s’agit de quatre Volumes in-quarto, accompagnés <lb/>d’un très grand nombre de Planches gravées en Taille-<lb/>douce, qui comprennent les Plans, Profils, & </s> <s xml:id="echoid-s114" xml:space="preserve">Elevations <lb/>des differens Sujets qu’on s’eſt propoſé de développer. <lb/></s> <s xml:id="echoid-s115" xml:space="preserve">De ces quatre Volumes, il y en a deux qui regardent l’Art <lb/>de ſortifier les Places dans toute ſorte de ſituation, la <lb/>Maniere de les attaquer & </s> <s xml:id="echoid-s116" xml:space="preserve">de les deffendre, relativement <pb file="0017" n="17" rhead="PRE’FACE."/> à ce qui s’eſt pratiqué de mieux depuis l’invention de la <lb/>Poudre: </s> <s xml:id="echoid-s117" xml:space="preserve">les deux autres ont pour objet la Conſtruction <lb/>des Fortifications & </s> <s xml:id="echoid-s118" xml:space="preserve">de tous les Ouvrages qui en font par-<lb/>tie; </s> <s xml:id="echoid-s119" xml:space="preserve">& </s> <s xml:id="echoid-s120" xml:space="preserve">c’eſt le premier de ces deux-là que je donne pre-<lb/>ſentement, puiſque l’Ordre naturel demande que l’on <lb/>parle de la Maniere de conſtruire les Places qu’on veut <lb/>fortifier, avant de donner des Maximes pour les attaquer & </s> <s xml:id="echoid-s121" xml:space="preserve"><lb/>les deffendre. </s> <s xml:id="echoid-s122" xml:space="preserve">Ce n’eſt pas que ces deux Objets n’ayent <lb/>un raport intime; </s> <s xml:id="echoid-s123" xml:space="preserve">auſſi l’a-t-on inſinué aux endroits <lb/>où il convenoit d’en faire mention: </s> <s xml:id="echoid-s124" xml:space="preserve">d’ailleurs, on n’a pas <lb/>voulu donner les quatre Volumes à la fois, afin d’avoir <lb/>plus de facilité pour l’Impreſſion, & </s> <s xml:id="echoid-s125" xml:space="preserve">ne point engager <lb/>le Public tout d’un coup dans une dépenſe qui auroit pû <lb/>gêner pluſieurs perſonnes. </s> <s xml:id="echoid-s126" xml:space="preserve">Ajoûtons, que les Volumes, qui <lb/>conviendroient aux uns, ne conviendroient peut-être pas <lb/>aux autres, ſelon le goût que l’on peut avoir pour les ma-<lb/>tieres qui interreſſent plus ou moins; </s> <s xml:id="echoid-s127" xml:space="preserve">chacun faiſant un <lb/>Traité à part, qui peut être détaché du reſte: </s> <s xml:id="echoid-s128" xml:space="preserve">c’eſt pour-<lb/>quoi, je ne m’arrêterai point à les détailler, pour ne m’at-<lb/>tacher uniquement qu’à celui-ci, afin d’éviter la confu-<lb/>ſion que pourroient faire naître tant de Sujets differens.</s> <s xml:id="echoid-s129" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s130" xml:space="preserve">Ce Volume eſt diviſé en ſix Livres. </s> <s xml:id="echoid-s131" xml:space="preserve">Dans le premier, <lb/>on enſeigne la Maniere d’appliquer les Principes de la <lb/>Mécanique à la Conſtruction des revêtemens de Maçon-<lb/>nerie, pour ſçavoir l’épaiſſeur qu’il faut leur donner par <lb/>raport à la pouſſée des terres qu’ils ont à ſoûtenir: </s> <s xml:id="echoid-s132" xml:space="preserve">on y <lb/>fait voir ſuivant quelle loy cette pouſſée agit, de quelle <lb/>réſiſtance les contreforts peuvent être capables, ſelon leur <lb/>longueur, leur épaiſſeur, & </s> <s xml:id="echoid-s133" xml:space="preserve">la diſtance où ils ſeroient les <lb/>uns des autres; </s> <s xml:id="echoid-s134" xml:space="preserve">en un mot, ce Livre comprend beaucoup <lb/>de choſes très-utiles, dont la plûpart n’avoient pas en-<lb/>core été traitées.</s> <s xml:id="echoid-s135" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s136" xml:space="preserve">Dans le ſecond, l’on conſidere de quelle maniere ſe fait <pb file="0018" n="18" rhead="PRE’FACE."/> la pouſſée des Voûtes, afin d’en tirer des Régles générales <lb/>& </s> <s xml:id="echoid-s137" xml:space="preserve">certaines pour déterminer l’épaiſſeur de leurs Piés-droits <lb/>ſelon la figure que l’on voudroit donner aux Voûtes dans <lb/>les differens uſages qu’on en fait pour les Fortifications, <lb/>ſoit aux Soûterrains, Portes de Ville, Magaſins à Poudre, <lb/>&</s> <s xml:id="echoid-s138" xml:space="preserve">c. </s> <s xml:id="echoid-s139" xml:space="preserve">On y parle auſſi des Culées des Ponts par raport à <lb/>la pouſſée des Arches, & </s> <s xml:id="echoid-s140" xml:space="preserve">de pluſieurs Obſervations tou-<lb/>chant l’execution de ces ſortes d’Ouvrages.</s> <s xml:id="echoid-s141" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s142" xml:space="preserve">Dans le troiſiéme, on trouvera pluſieurs Diſſertations ſur <lb/>les qualités & </s> <s xml:id="echoid-s143" xml:space="preserve">le choix des matériaux, avec la maniere de <lb/>les mettre en œuvre dans toute ſorte de travaux, les dé-<lb/>tails dans leſquels il faut entrer pour en faire les Eſtima-<lb/>tions & </s> <s xml:id="echoid-s144" xml:space="preserve">les Devis, ce qu’il faut obſerver dans les grands <lb/>Atteliers pour le tranſport & </s> <s xml:id="echoid-s145" xml:space="preserve">le remuement des terres, la <lb/>façon de les employer & </s> <s xml:id="echoid-s146" xml:space="preserve">comme on doit conſtruire les <lb/>Voûtes des ſoûterrains. </s> <s xml:id="echoid-s147" xml:space="preserve">On s’eſt étendu particulierement <lb/>ſur les differentes eſpeces de fondemens qu’on pouvoit <lb/>faire dans toute ſorte d’endroits, principalement dans <lb/>ceux qui preſentent de grands obſtacles à vaincre: </s> <s xml:id="echoid-s148" xml:space="preserve">& </s> <s xml:id="echoid-s149" xml:space="preserve">pour <lb/>tout dire enfin, on a ſupoſé dans ce Livre qu’on avoit une <lb/>Place neuve à bâtir, pour avoir lieu de parler de tous les <lb/>gros Ouvrages de Fortification, & </s> <s xml:id="echoid-s150" xml:space="preserve">d’en montrer la conduite <lb/>depuis le tracé du projet juſqu’à ſon entiere execution.</s> <s xml:id="echoid-s151" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s152" xml:space="preserve">Dans le quatriéme, on a eû pour objet la Conſtruction <lb/>de tous les Edifices qui ſe font aux Places de Guerre, <lb/>comme ſont les Portes de Ville, Corps de Gardes, Redou-<lb/>tes, Magaſins, Arſenaux, Cazernes, Boulangeries, Can-<lb/>tines, Citernes, &</s> <s xml:id="echoid-s153" xml:space="preserve">c. </s> <s xml:id="echoid-s154" xml:space="preserve">On y donne auſſi des Régles genera-<lb/>les pour l’Architecture Civile, & </s> <s xml:id="echoid-s155" xml:space="preserve">des Principes ſur la force <lb/>des Bois de Charpente; </s> <s xml:id="echoid-s156" xml:space="preserve">enfin, on eſt entré dans le détail <lb/>de toutes les differentes parties qui ſe rencontrent dans la <lb/>Conſtruction des Edifices.</s> <s xml:id="echoid-s157" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s158" xml:space="preserve">Dans le cinquiéme, on enſeigne ce qui peut apartenir <pb file="0019" n="19" rhead="PRE’FACE."/> à la Décoration, c’eſt-à-dire, que l’on y donne les cinq <lb/>Ordres d’Architecture, avec les Régles & </s> <s xml:id="echoid-s159" xml:space="preserve">les Maximes des <lb/>plus fameux Architectes tant anciens que modernes, pour <lb/>orner les Bâtimens & </s> <s xml:id="echoid-s160" xml:space="preserve">leur donner cette Elegance qui les <lb/>diſtingue du commun.</s> <s xml:id="echoid-s161" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s162" xml:space="preserve">Enfin, dans le ſixiéme Livre on montre la Maniere de <lb/>faire les Devis de tous les Ouvrages contenus dans les <lb/>précédens: </s> <s xml:id="echoid-s163" xml:space="preserve">on en raporte des Exemples détaillés & </s> <s xml:id="echoid-s164" xml:space="preserve">cir-<lb/>conſtanciés avec le plus de neteté qu’il a été poſſible: </s> <s xml:id="echoid-s165" xml:space="preserve">on <lb/>y trouvera auſſi pluſieurs Obſervations ſur la forme des <lb/>Adjudications, & </s> <s xml:id="echoid-s166" xml:space="preserve">les Conditions ſous leſquelles on doit <lb/>paſſer les Marchés aux Entrepreneurs. </s> <s xml:id="echoid-s167" xml:space="preserve">Et, pour rendre ce <lb/>Livre plus inſtructif, & </s> <s xml:id="echoid-s168" xml:space="preserve">ſuivre l’Eſprit du troiſiéme & </s> <s xml:id="echoid-s169" xml:space="preserve">du <lb/>quatriéme, on a commencé par donner un Modéle de <lb/>Devis general pour une Place neuve qu’on auroit à conſ-<lb/>truire, accompagné de quelques autres Devis particuliers <lb/>qui ſerviront pour dreſſer ceux des Ouvrages qui ſe font le <lb/>plus ordinairement dans les Places.</s> <s xml:id="echoid-s170" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s171" xml:space="preserve">Comme ces ſix Livres font autant de petits Traités <lb/>complets dans leur genre, on a affecté en les imprimant <lb/>de les détacher les uns des autres, afin de contribuer à la <lb/>ſatisfaction de pluſieurs perſonnes qui deſiroient les avoir <lb/>ſéparés, oules faire relier en deux Tomes, plus commodes, <lb/>ſelon eux, que s’ils n’étoient qu’en un ſeul; </s> <s xml:id="echoid-s172" xml:space="preserve">c’eſt pour-<lb/>quoi les pages de chaque Livre ſont cottées à part. </s> <s xml:id="echoid-s173" xml:space="preserve">J’ajoû-<lb/>terai auſſi, que dans le premier & </s> <s xml:id="echoid-s174" xml:space="preserve">le ſecond, & </s> <s xml:id="echoid-s175" xml:space="preserve">dans la <lb/>ſuite des autres, lorſque l’on verra à la marge V. </s> <s xml:id="echoid-s176" xml:space="preserve">le C. </s> <s xml:id="echoid-s177" xml:space="preserve">art. <lb/></s> <s xml:id="echoid-s178" xml:space="preserve">& </s> <s xml:id="echoid-s179" xml:space="preserve">c. </s> <s xml:id="echoid-s180" xml:space="preserve">Cela veut dire, Voyez tel article du Cours de Mathe-<lb/>matique. </s> <s xml:id="echoid-s181" xml:space="preserve">J’entends celui que j’ai fait à l’uſage de l’Artille-<lb/>rie & </s> <s xml:id="echoid-s182" xml:space="preserve">du Génie, qui ſe trouve chez le même Libraire qui <lb/>vend mes Ouvrages; </s> <s xml:id="echoid-s183" xml:space="preserve">car, comme ce Cours a été compoſé <lb/>exprès pour faciliter l’Intelligence des choſes de Théorie <lb/>qui demandoient des Connoiſſances préliminaires, & </s> <s xml:id="echoid-s184" xml:space="preserve">que <pb file="0020" n="20" rhead="PRE’FACE."/> j’aurois eû peine à indiquer ailleurs, il étoit naturel que <lb/>j’y euſſe recours plutôt qu’à tout autre.</s> <s xml:id="echoid-s185" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s186" xml:space="preserve">A l’égard du ſecond Volume, on y trouvera generale-<lb/>ment tous les Ouvrages qui apartiennent à l’Architecture <lb/>Hydraulique, avec un Dictionnaire fort ample des Termes <lb/>propres à la Fortification & </s> <s xml:id="echoid-s187" xml:space="preserve">à l’Architecture; </s> <s xml:id="echoid-s188" xml:space="preserve">& </s> <s xml:id="echoid-s189" xml:space="preserve">j’ôſe bien <lb/>aſſurer, que ce Volume ſera au moins auſſi interreſſant que <lb/>le premier. </s> <s xml:id="echoid-s190" xml:space="preserve">Ayant encore des Augmentations à y faire, il <lb/>ne paroîtra pas cette année, comme je l’avois fait eſperer; <lb/></s> <s xml:id="echoid-s191" xml:space="preserve">mais, le Public n’y perdra rien, je tacherai de payer avec <lb/>uſure l’attente de ceux qui voudront bien y prendre quel-<lb/>que part: </s> <s xml:id="echoid-s192" xml:space="preserve">d’ailleurs, il eſt à propos que je ſache le Juge-<lb/>ment qu’on portera de celui-ci, afin que ſi j’aprenois qu’il y <lb/>eût des Augmentations ou des Corrections à y faire, on pût <lb/>les donner par Suplément. </s> <s xml:id="echoid-s193" xml:space="preserve">Pour les Fautes d’Impreſſion, <lb/>je ne doute pas qu’on n’en rencontre quelques-unes; </s> <s xml:id="echoid-s194" xml:space="preserve">mais, <lb/>je ne les crois point aſſez de conſequence pour arrêter le <lb/>Lecteur: </s> <s xml:id="echoid-s195" xml:space="preserve">c’eſt pourquoi, je n’ai pas fait d’Errata.</s> <s xml:id="echoid-s196" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s197" xml:space="preserve">Malgré toutes les Meſures que j’ai pu prendre, pour ren-<lb/>dre cet Ouvrage le plus achevé qu’il m’a été poſſible, j’ai <lb/>cru ne devoir le mettre au jour, qu’après l’avoir expoſé <lb/>tout de nouveau à la Cenſure des Ingenieurs du premier <lb/>ordre; </s> <s xml:id="echoid-s198" xml:space="preserve">& </s> <s xml:id="echoid-s199" xml:space="preserve">Mr. </s> <s xml:id="echoid-s200" xml:space="preserve">le Marquis Dasfeld ayant bien voulu s’inter-<lb/>reſſer à tout ce qui pouvoit perfectionner mon deſſein, <lb/>je l’ai prié de me nommer pour Commiſſaires quatre Di-<lb/>recteurs des Fortifications: </s> <s xml:id="echoid-s201" xml:space="preserve">auſſi-tôt qu’il ſe fut rendu à <lb/>mes inſtances, je leur préſentai mon Manuſcrit, qu’ils pri-<lb/>rent la peine d’examiner conjointement avec les Inge-<lb/>nieurs en Chef & </s> <s xml:id="echoid-s202" xml:space="preserve">les autres qui ſe ſont trouvés ſur les lieux. <lb/></s> <s xml:id="echoid-s203" xml:space="preserve">Et comme il eſt permis de ſe faire honneur des Approba-<lb/>tions que les Perſonnes équitables & </s> <s xml:id="echoid-s204" xml:space="preserve">éclairées veulent <lb/>bien nous accorder, voici celles de Meſſieurs de Vauban, <lb/>Demus, de Vallory, & </s> <s xml:id="echoid-s205" xml:space="preserve">Gittard.</s> <s xml:id="echoid-s206" xml:space="preserve"/> </p> <pb file="0021" n="21" rhead="APPROBATIONS."/> <p style="it"> <s xml:id="echoid-s207" xml:space="preserve">NOUS Lieutenant General des Armées du Roy, Grand-Croix de l’Ordre <lb/>Militaire de Saint Louïs, Gouverneur des Ville & </s> <s xml:id="echoid-s208" xml:space="preserve">Chateau de Bethune, <lb/>Directeur des Fortifications des Places de la Province d’Artois; </s> <s xml:id="echoid-s209" xml:space="preserve">certifions avoir lû <lb/>& </s> <s xml:id="echoid-s210" xml:space="preserve">examiné, à la recommandation de M le Marquis Dasfeld, avec autant d’ex-<lb/>actitude qu’il nous a été poſſible, un Manuſcrit intitulé la Science des Ingenieurs <lb/>dans la conduite des travaux de Fortification, par M. </s> <s xml:id="echoid-s211" xml:space="preserve">de Belidor, dans le-<lb/>quel nous n’avons rien trouvé qui ne ſoit conforme à ce qui ſe pratique de mieux pour <lb/>la conſtruction des Ouvrages de Fortification, Ecluſes, & </s> <s xml:id="echoid-s212" xml:space="preserve">Edifices Militaires: </s> <s xml:id="echoid-s213" xml:space="preserve">la <lb/>plûpart des matieres qui étoient ſuſceptibles des regles de Geometrie, y ſont traitées <lb/>avec préciſion & </s> <s xml:id="echoid-s214" xml:space="preserve">netteté, ce qui pourra contribuer à la perfection des Ouvrages; </s> <s xml:id="echoid-s215" xml:space="preserve">je <lb/>juge même que les Ingenieurs pourront ſe ſervir très-utilement des régles qui y ſont <lb/>enſeignées, & </s> <s xml:id="echoid-s216" xml:space="preserve">qu’en general ce Livre ne peut être que très-avantageux au Service <lb/>du Roy & </s> <s xml:id="echoid-s217" xml:space="preserve">à ceux qui ſont chargez de la Conſtruction des Ouvrages de ſa Ma-<lb/>jeſté. </s> <s xml:id="echoid-s218" xml:space="preserve">Fait à Bethune ce 17 May 1728. </s> <s xml:id="echoid-s219" xml:space="preserve">Signé, <emph style="sc">DE</emph> <emph style="sc">Vauban</emph>.</s> <s xml:id="echoid-s220" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s221" xml:space="preserve">Nous ſouſſigné Chevalier de l’Ordre Royal & </s> <s xml:id="echoid-s222" xml:space="preserve">Militaire de Saint Louïs, Bri-<lb/>gadier des Armées du Roy, Ingenieur, Directeur des Fortifications des Places du <lb/>Soiſſonnois & </s> <s xml:id="echoid-s223" xml:space="preserve">de partie de celles de Picardie; </s> <s xml:id="echoid-s224" xml:space="preserve">certifions avoir vû, lû, & </s> <s xml:id="echoid-s225" xml:space="preserve">examiné <lb/>par ordre de M. </s> <s xml:id="echoid-s226" xml:space="preserve">le Marquis Dasfeld avec toute l’attention dont nous ſommes capa-<lb/>bles, un Manuſcrit contenant 22. </s> <s xml:id="echoid-s227" xml:space="preserve">Cahiers, accompagné d’un grand nombre de <lb/>Planches qui doivent compoſer un Ouvrage intitulé la Science des Ingenieurs <lb/>dans la conduite des travaux de Fortification, par M. </s> <s xml:id="echoid-s228" xml:space="preserve">de Belidor, dans le-<lb/>quel nous n’avons rien reconnu qui ne ſoit très-bon, très-utile au Service du Roy, <lb/>& </s> <s xml:id="echoid-s229" xml:space="preserve">avantageux à tous ceux qui s’appliquent à la Profeſſion d’Ingenieur; </s> <s xml:id="echoid-s230" xml:space="preserve">les matie-<lb/>res y étant traitées ſelon l’uſage que j’ai vû pratiquer dans pluſieurs Places depuis <lb/>56. </s> <s xml:id="echoid-s231" xml:space="preserve">ans que je fais travailler. </s> <s xml:id="echoid-s232" xml:space="preserve">Fait à S. </s> <s xml:id="echoid-s233" xml:space="preserve">Quentin le 28 d’Avril 1728. </s> <s xml:id="echoid-s234" xml:space="preserve">Signé, <lb/><emph style="sc">Demus</emph>.</s> <s xml:id="echoid-s235" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s236" xml:space="preserve">Nous ſouſſigné Chevalier de l’Ordre Militaire de S. </s> <s xml:id="echoid-s237" xml:space="preserve">Louïs, Directeur des For-<lb/>tifications de la Flandre; </s> <s xml:id="echoid-s238" xml:space="preserve">certifions avoir vû, lû, & </s> <s xml:id="echoid-s239" xml:space="preserve">examiné avec ſoin, par ordre <lb/>de M. </s> <s xml:id="echoid-s240" xml:space="preserve">le Marquis Dasfeld, un Manuſcrit accompagné de Planches, qui a pour <lb/>titre la Science des Ingenieurs dans la conduite des travaux de Fortification, <lb/>par M. </s> <s xml:id="echoid-s241" xml:space="preserve">de Belidor, dans lequel nous n’avons rien trouvé que de très-bon, très-<lb/>utile, & </s> <s xml:id="echoid-s242" xml:space="preserve">demontré avec toute l’exactitude & </s> <s xml:id="echoid-s243" xml:space="preserve">la capacité requiſe, tant Geometrique-<lb/>ment que par la pratique ordinaire, & </s> <s xml:id="echoid-s244" xml:space="preserve">jugeons que ce travail ne peut être que <lb/>très-utile & </s> <s xml:id="echoid-s245" xml:space="preserve">avantageux pour le Service du Roy, & </s> <s xml:id="echoid-s246" xml:space="preserve">à ceux qui s’appliquent à la <lb/>connoiſſance des Fortifications, puiſqu’ils ne pourront point ſe ſervir d’une Methode <lb/>plus facile & </s> <s xml:id="echoid-s247" xml:space="preserve">plus exacte que celle qui y eſt démontrée. </s> <s xml:id="echoid-s248" xml:space="preserve">Fait au Queſnoy ce 2 May <lb/>1728. </s> <s xml:id="echoid-s249" xml:space="preserve">Signé, <emph style="sc">Vallory</emph>.</s> <s xml:id="echoid-s250" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s251" xml:space="preserve">Nous ſouſſigné Chevalier de l’Ordre Militaire de S. </s> <s xml:id="echoid-s252" xml:space="preserve">Louïs, Commandant pour <lb/>le Roy au Fort de S. </s> <s xml:id="echoid-s253" xml:space="preserve">Sauveur de Lille, Ingenieur ordinaire du Roy, ayant la Di-<lb/>rection des Fortifications des Ville & </s> <s xml:id="echoid-s254" xml:space="preserve">Citadelle de Lille; </s> <s xml:id="echoid-s255" xml:space="preserve">certifions avoir vû, lû, <pb file="0022" n="22"/> & </s> <s xml:id="echoid-s256" xml:space="preserve">examiné avec ſoin un Manuſcrit qui a pour titre la Science des Ingenieurs <lb/>dans la conduite des travaux de Fortification, par M. </s> <s xml:id="echoid-s257" xml:space="preserve">de Belidor, dans le-<lb/>quel nous n’avons rien trouvé que de très bon & </s> <s xml:id="echoid-s258" xml:space="preserve">très-utile, bien démontré Geome-<lb/>triquement dans pluſieurs parties eſſentielles qui n’avoient été juſqu’apreſent miſes <lb/>en uſage que par pratique, ce qui pourra beaucoup contribuer à la perfection des <lb/>Ouvrages de Fortifications, & </s> <s xml:id="echoid-s259" xml:space="preserve">devenir très-utile pour le Service du Roy, & </s> <s xml:id="echoid-s260" xml:space="preserve">à <lb/>perfectionner les jeunes Ingenieurs, qui trouveront dans ce Traité avec beaucoup <lb/>d’exactitude & </s> <s xml:id="echoid-s261" xml:space="preserve">de netteté ce qui ne ſe rencontre point dans aucuns des Auteurs qui <lb/>ont traité des Fortifications. </s> <s xml:id="echoid-s262" xml:space="preserve">Fait à Lille ce 9 May 1728. </s> <s xml:id="echoid-s263" xml:space="preserve">Signé, <emph style="sc">Gittard</emph>.</s> <s xml:id="echoid-s264" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s265" xml:space="preserve">Ayant traité dans le cinquiéme Livre, comme je l’ai inſinué cy-devant, <lb/>tout ce qu’on pouvoit dire de plus eſſentiel ſur les Ordres d’Architecture, <lb/>j’ai conſulté auſſi Meſſieurs les Architectes du Roy, entr’autres Mr. </s> <s xml:id="echoid-s266" xml:space="preserve">de Cot-<lb/>te, qui a bien voulu prendre la peine d’examiner, non-ſeulement ce qui appar-<lb/>tenoit à la Décoration, mais encore les autres Parties de cet Ouvrage; </s> <s xml:id="echoid-s267" xml:space="preserve">& </s> <s xml:id="echoid-s268" xml:space="preserve"><lb/>voici le Jugement qu’il en a porté.</s> <s xml:id="echoid-s269" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s270" xml:space="preserve">Nous ſouſſigné Chevalier de l’Ordre de S. </s> <s xml:id="echoid-s271" xml:space="preserve">Michel, premier Architecte, Inten-<lb/>dant des Bâtimens, Arts, & </s> <s xml:id="echoid-s272" xml:space="preserve">Manufactures du Roy, Directeur de l’Academie Ro-<lb/>yale d’Architecture; </s> <s xml:id="echoid-s273" xml:space="preserve">certifions avoir lû & </s> <s xml:id="echoid-s274" xml:space="preserve">examiné avec beaucoup de ſoin un Ma-<lb/>nuſcrit accompagné d’un grand nombre de Planches, qui compoſent un Livre intitulé <lb/>la Science des Ingenieurs dans la conduite des travaux de Fortification par <lb/>M. </s> <s xml:id="echoid-s275" xml:space="preserve">de Belidor, dans lequel nous n’avons rien trouvé qui ne ſoit traité avec beau-<lb/>coup de méthode & </s> <s xml:id="echoid-s276" xml:space="preserve">de capacité, les choſes les plus ordinaires y étant miſes dans un <lb/>jour qui les rend intereſſantes, & </s> <s xml:id="echoid-s277" xml:space="preserve">celles qui ſont d’une plus grande conſideration étant <lb/>perfectionnées par de nouvelles régles qui rendent cet Ouvrage digne des éloges des <lb/>plus habiles Gens, rien n’étant mieux traité que la Mécanique & </s> <s xml:id="echoid-s278" xml:space="preserve">Conſtruction des <lb/>Revêtemens de Terraſſes & </s> <s xml:id="echoid-s279" xml:space="preserve">des Voûtes: </s> <s xml:id="echoid-s280" xml:space="preserve">c’eſt le Jugement que j’ai crû en devoir por-<lb/>ter dans les ſentimens de rendre juſtice à l’Auteur qui travaille avec tant de zele <lb/>pour la perfection des Arts & </s> <s xml:id="echoid-s281" xml:space="preserve">des Sciences. </s> <s xml:id="echoid-s282" xml:space="preserve">Fait à Paris ce 24 May 1728. </s> <s xml:id="echoid-s283" xml:space="preserve">Signé, <lb/><emph style="sc">DE</emph> <emph style="sc">Cotte</emph>.</s> <s xml:id="echoid-s284" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s285" xml:space="preserve">J’ay lû, par l’Ordre de Monſeigneur le Garde des Sçeaux, un Manuſcrit qui a <lb/>pour titre la Science des Ingenieurs dans la conduite des Travaux de Fortifi-<lb/>cation; </s> <s xml:id="echoid-s286" xml:space="preserve">& </s> <s xml:id="echoid-s287" xml:space="preserve">j’ai crû que l’Impreſſion de cet Ouvrage feroit plaiſir à ceux qui ſont <lb/>dans ces Travaux, & </s> <s xml:id="echoid-s288" xml:space="preserve">ſeroit d’une grande utilité. </s> <s xml:id="echoid-s289" xml:space="preserve"><emph style="sc">Fait</emph> à Paris le 25. </s> <s xml:id="echoid-s290" xml:space="preserve">May <lb/>1728. </s> <s xml:id="echoid-s291" xml:space="preserve"><emph style="sc">Saurin</emph>.</s> <s xml:id="echoid-s292" xml:space="preserve"/> </p> <pb file="0023" n="23"/> <figure> <image file="0023-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0023-01"/> </figure> </div> <div xml:id="echoid-div7" type="section" level="1" n="7"> <head xml:id="echoid-head6" xml:space="preserve">LA SCIENCE <lb/>DES INGENIEURS <lb/>DANS LA CONDUITE DES TRAVAUX <lb/>DE FORTIFICATION.</head> <head xml:id="echoid-head7" xml:space="preserve">LIVRE PREMIER.</head> <p style="it"> <s xml:id="echoid-s293" xml:space="preserve">Où l’on enſeigne la maniere de ſe ſervir des principes de la <lb/>Mécanique, pour donner les dimenſions qui conviennent aux <lb/>revêtemens des Ouvrages de Fortification, pour être en <lb/>équilibre, avec la pouſſée des Terres qu’ils ont à ſoûtenir.</s> <s xml:id="echoid-s294" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s295" xml:space="preserve"><emph style="sc">DEpuis</emph> qu’on a cherché dans les Mathematiques les <lb/>moyens de perfectionner les Arts, on y a fait des <lb/>progrès qu’on n’eût oſé eſperer auparavant; </s> <s xml:id="echoid-s296" xml:space="preserve">mais <lb/>comme il n’y a qu’un petit nombre de perſonnes <lb/>qui ſont en état de juger juſqu’où peut mener cette <lb/>ſcience, on a peine à ſe perſuader qu’elle ſoit capable de toutes <lb/>les merveilles qu’on lui attribuë, ce que l’on a découvert de <lb/>plus avantageux, étant juſtement ce qui eſt ignoré du Public, <pb o="2" file="0024" n="24" rhead="LA SCIENCE DES INGENIEURS,"/> & </s> <s xml:id="echoid-s297" xml:space="preserve">même de ceux quipourroient s’en ſervir utilement, par l’éloigne-<lb/>ment où ils ſont de comprendre les principes qui ont conduit à la <lb/>recherche d’une infinité de choſes utiles, à moins qu’ils ne s’en <lb/>inſtruiſent & </s> <s xml:id="echoid-s298" xml:space="preserve">neſe mettent, pour ainſi dire, eux-mêmes en état de <lb/>faire des découvertes: </s> <s xml:id="echoid-s299" xml:space="preserve">d’ailleurs l’opinion qu’il n’y a que la ſeule <lb/>pratique qui peut les mener au but, eſt encore un obſtacle qui <lb/>n’eſt pas le moins difficile à vaincre, il eſt bien vrai que l’experience <lb/>contribuë beaucoup à donner des connoiſſances nouvelles, & </s> <s xml:id="echoid-s300" xml:space="preserve">qu’elle <lb/>fournit tous les jours aux plus habiles gens des ſujets de reflexion <lb/>dont ils ne ſe ſeroient peut-être point aviſés ſi elle ne les avoit <lb/>fait naître. </s> <s xml:id="echoid-s301" xml:space="preserve">Mais il faut que cette experience ſoit éclairée, ſans quoi, <lb/>l’on ne peut avoir que des idées très-confuſes ſur tout ce qui ſe <lb/>preſente, on voit toûjours les objets par la même face, on veut <lb/>qu’ils ſoient tels qu’on nous a dit qu’ils étoient, ou tels qu’il a plû <lb/>à notre imagination de nous les répreſenter: </s> <s xml:id="echoid-s302" xml:space="preserve">& </s> <s xml:id="echoid-s303" xml:space="preserve">qu’on ſoit dans le <lb/>vrai ou non, on paſſe toute ſa vie ſans rien ſçavoir de juſte & </s> <s xml:id="echoid-s304" xml:space="preserve">de <lb/>précis ſur ce que l’on croit pourtant poſſeder le mieux. </s> <s xml:id="echoid-s305" xml:space="preserve">Delà vient <lb/>que bien des choſes imparfaites demeurent toujours dans le même <lb/>état, elles ſe tranſmettent d’une poſterité à l’autre avec les mêmes <lb/>défauts; </s> <s xml:id="echoid-s306" xml:space="preserve">& </s> <s xml:id="echoid-s307" xml:space="preserve">ſi par hazard quelqu’un s’aviſe de les remarquer, auſſi-<lb/>tôt tous les gens du métier ſe révoltent contre la nouveauté, l’on <lb/>a peine à ſe figurer que ceux qui n’ont point travaillé toute leur <lb/>vie à certains ouvrages, puiſſent en raiſonner juſte, & </s> <s xml:id="echoid-s308" xml:space="preserve">la verité toute <lb/>eſtimable qu’elle eſt ſe trouve ſouvent obligée de garder le ſilence, <lb/>ou de prendre des meſures & </s> <s xml:id="echoid-s309" xml:space="preserve">des ménagemens pour s’inſinuer <lb/>Cela vient ſans doute, de ce que la plûpart des hommes ne con-<lb/>ſultent point aſſés la raiſon; </s> <s xml:id="echoid-s310" xml:space="preserve">eſclaves du préjugé, c’eſt preſque toû-<lb/>jours l’uſage qui les détermine; </s> <s xml:id="echoid-s311" xml:space="preserve">& </s> <s xml:id="echoid-s312" xml:space="preserve">pour ne parler que de l’Archi-<lb/>tecture, qui eſt le ſeul objet que j’ai en vûë, n’eſt-il pas ſurpre-<lb/>nant que depuis le tems qu’on la cultive, on l’ait ſi peu perfection-<lb/>née en certains points eſſentiels qui en ſont comme la baſe; </s> <s xml:id="echoid-s313" xml:space="preserve">car ſi <lb/>l’on en excepte quelques régles de convenance & </s> <s xml:id="echoid-s314" xml:space="preserve">de goût, qui <lb/>appartiennent à la décoration, on n’a rien d’aſſés précis ni d’exact <lb/>ſur la plûpat du reſte, aucun Architecte n’a donné des principes <lb/>pour trouver le point d’équilibre entre les forces agiſſantes & </s> <s xml:id="echoid-s315" xml:space="preserve">cel-<lb/>les qui doivent reſiſter, on ne ſçait pas, par exemple, quelle épaiſ-<lb/>ſeur il faut donner aux revêtemens des Terraſſes, ou à ceux des Rem-<lb/>pars, des Quays & </s> <s xml:id="echoid-s316" xml:space="preserve">des Chauſſées, aux piés-droits des Voutes, aux <lb/>Culées des Ponts, pour être en équilibre par leur réſiſtance avec <lb/>la pouſſée que ces differens murs doivent ſoûtenir, ſans y employer <lb/>des matériaux ſuperſlus.</s> <s xml:id="echoid-s317" xml:space="preserve"/> </p> <pb o="3" file="0025" n="25" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> <p> <s xml:id="echoid-s318" xml:space="preserve">S’il manque quelque choſe à l’Architecture, c’eſt que ceux <lb/>qui en ont traité, ont voulu tirer tout du même fond, & </s> <s xml:id="echoid-s319" xml:space="preserve">ſe paſſer <lb/>des ſecours qu’ils ont crû étrangers à leur ſujet, n’ayant pas conſi-<lb/>deré que les ſciences doivent ſe donner des lumieres mutuelles, <lb/>& </s> <s xml:id="echoid-s320" xml:space="preserve">que celle-ci roulant ſur des rapports, il n’y avoit que les Ma-<lb/>thématiques qui puſſent les déterminer, ils ont pourtant bien ſenti <lb/>qu’il leur manquoit quelque choſe, mais comme la plûpart n’avoient <lb/>que très-peu ou point du tout de connoiſſance de la Mécanique ni <lb/>de l’Algebre, qui ſeules pouvoient donner ce qu’ils cherchoient, <lb/>il n’eſt pas étonnant qu’ils n’y ayent point eu recours, & </s> <s xml:id="echoid-s321" xml:space="preserve">qu’ils s’en <lb/>ſoient tenu à une certaine pratique, quià la verité leur a réüſſi dans <lb/>bien des cas, parce qu’ils n’ont point épargné les matériaux, quand <lb/>ils ont eu quelque ſujet d’aprehender queleur ouvrage ne fut point <lb/>aſſés ſolide.</s> <s xml:id="echoid-s322" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s323" xml:space="preserve">Aprés cela quand on parviendroit à trouver des régles qui don-<lb/>neroient à l’Architecture toute la perfection poſſible, il eſt à crain-<lb/>dre qu’on n’en tire pas toute l’utilité qu’on pouroit ſe promettre; <lb/></s> <s xml:id="echoid-s324" xml:space="preserve">parce que les régles que les Géometres donneront ne pourront pas <lb/>être entenduës auſſi aiſément qu’on a coûtume d’entendre les Livres <lb/>ordinaires de l’Architecture, & </s> <s xml:id="echoid-s325" xml:space="preserve">qu’il faudra abſolument employer <lb/>l’Algebre & </s> <s xml:id="echoid-s326" xml:space="preserve">la Mécanique, ces ſortes de choſes ne pouvant s’ex-<lb/>pliquer dans un autre langage. </s> <s xml:id="echoid-s327" xml:space="preserve">On aura beau dire qu’on n’y com-<lb/>prend rien, ce ne ſera point la faute de ceux qui auront fait de <lb/>leur mieux pour donner des principes nouveaux & </s> <s xml:id="echoid-s328" xml:space="preserve">plus certains <lb/>que ceux que l’on avoit. </s> <s xml:id="echoid-s329" xml:space="preserve">Mais pourquoi, dira-t’-on, vouloir aſſujet-<lb/>tir l’Architecture à tant de connoiſſances abſtraites? </s> <s xml:id="echoid-s330" xml:space="preserve">Les Architectes <lb/>juſqu’ici n’ont pas ſçû l’Algebre, & </s> <s xml:id="echoid-s331" xml:space="preserve">leurs ouvrages n’en ſont pas <lb/>moins ſolides, ni moins beaux. </s> <s xml:id="echoid-s332" xml:space="preserve">Je conviens qu’on ne ſauroit trop <lb/>les admirer, & </s> <s xml:id="echoid-s333" xml:space="preserve">qu’il eſt ſurprenant qu’ils ayent pu ſe paſſer desré-<lb/>gles dont je parle; </s> <s xml:id="echoid-s334" xml:space="preserve">cela vient apparemment du long uſage où ils <lb/>ont été de faire executer ſouvent la même choſe, qui leur a fourni <lb/>certaines pratiques dont ils ſe ſont bien trouvés; </s> <s xml:id="echoid-s335" xml:space="preserve">mais quel tems <lb/>ne leur a-t’-il pas fallu avant d’être capables de travailler hardiment? </s> <s xml:id="echoid-s336" xml:space="preserve"><lb/>A peine toute leur vie a-t-elle pû ſuffire; </s> <s xml:id="echoid-s337" xml:space="preserve">la malheureuſe condition <lb/>des hommes étant d’arriver au dernier terme de leurs jours lorſ-<lb/>qu’ils commencent ſeulement à ſavoir quelque choſe; </s> <s xml:id="echoid-s338" xml:space="preserve">il faudroit <lb/>donc pour tirer le meilleur parti qu’il eſt poſſible d’une vie ſi cour-<lb/>te apprendre avec méthode, ce qu’on a envie de ſavoir, avoir <lb/>des régles ſures & </s> <s xml:id="echoid-s339" xml:space="preserve">démontrées, afin qu’en étant une fois préve-<lb/>nu, on ne ſoit pas obligé d’attendre que l’experience ou le hazard <lb/>nous les apprenne; </s> <s xml:id="echoid-s340" xml:space="preserve">ainſi dans quelque profeſſion que l’on ſoit, il <pb o="4" file="0026" n="26" rhead="LA SCIENCE DES INGENIEURS,"/> faut entrer dans ſa carriere avec le plus de fond qu’il eſt poſſible, <lb/>enſuite mettre à profit nos réflexions, ou celles des autres, ſur les <lb/>differens cas qui ſe preſentent; </s> <s xml:id="echoid-s341" xml:space="preserve">c’eſt-à-dire, qu’il ſeroit à ſouhaiter <lb/>qu’on commençât où ceux qui nous ont précédé ont fini, parce que <lb/>ce qu’ils nous auront laiſſé, nous inſtruira preſque autant que ſi nous <lb/>l’avions pratiqué nous mêmes; </s> <s xml:id="echoid-s342" xml:space="preserve">mais quoique bien des choſes leur <lb/>ayent réüſſi, il eſt à propos de ne les imiter que dans celles où <lb/>l’on apercevra les raiſons qu’ils ont eu d’agir de telle & </s> <s xml:id="echoid-s343" xml:space="preserve">telle ma-<lb/>niere, car comme les lieux, les circonſtances, les differentes eſpe-<lb/>ces de matériaux peuvent favoriſer ou alterer l’execution d’une <lb/>même choſe, il ſeroit à craindre que ce qui a réüſſi aux uns, ne <lb/>faſſe échoüer les autres. </s> <s xml:id="echoid-s344" xml:space="preserve">Ainſi pour commencer à ſuivre la mé-<lb/>thode ſelon laquelle il m’a paru que l’Architecture devoit être <lb/>traitée, (c’eſt-à-dire, cette Architecture qui apartient princi-<lb/>palement à l’Ingenieur,) nous allons enſeigner dans ce Livre-ci <lb/>une nouvelle théorie pour régler l’épaiſſeur des revêtemens de <lb/>maçonnerie, qui, à ce que je croi, ſera bien reçûë de ceux qui ſe-<lb/>ront à portée de l’entendre, puiſqu’ils y trouveront la réſolution <lb/>d’un grand nombre de Problemes utiles, dont ils pouront tirer <lb/>beaucoup de connoiſſances: </s> <s xml:id="echoid-s345" xml:space="preserve">j’aurois bien voulu me ſervir d’une autre <lb/>voïe que celle de l’Algébre pour me faire<unsure/> entendre, mais je n’ai <lb/>pû m’en paſſer; </s> <s xml:id="echoid-s346" xml:space="preserve">ce qui me fait aprehender que ceux qui ne ſont <lb/>que trop prévenus contre cette ſcience, ne ſe previennent auſſi <lb/>contre mon Ouvrage & </s> <s xml:id="echoid-s347" xml:space="preserve">n’en tirent pas tout le fruit que j’ai eu <lb/>en vûë de leur procurer: </s> <s xml:id="echoid-s348" xml:space="preserve">je n’ai pourtant rien négligé pour me <lb/>faire entendre clairement, je me ſuis ſervi par-tout des expreſſions <lb/>les plus ſimples, terminant chaque propoſition par un calcul Arith-<lb/>metique, & </s> <s xml:id="echoid-s349" xml:space="preserve">par des aplications qui pouront être entenduës de <lb/>tout le monde, n’ayant pas voulu conſtruire mes égalités ſelon la <lb/>méthode ordinaire des Géométres, crainte de donner à mon Ou-<lb/>vrage un air ſavant qui n’auroit fait que le rendre encore plus inac-<lb/>ceſſible à ceux pour qui j’écris.</s> <s xml:id="echoid-s350" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s351" xml:space="preserve">Comme avant toutes choſes, il faut connoître les centres de gra-<lb/>vité de Figures ſur leſquelles nous ſerons obligé d’operer, je vais <lb/>enſeigner ce qu’il faut ſavoir là-deſſus dans le Chapitre ſuivant.</s> <s xml:id="echoid-s352" xml:space="preserve"/> </p> <pb o="5" file="0027" n="27" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div8" type="section" level="1" n="8"> <head xml:id="echoid-head8" xml:space="preserve">CHAPITRE PREMIER.</head> <head xml:id="echoid-head9" style="it" xml:space="preserve">Où l’on donne la maniere de trouver les centres de gravité de <lb/>pluſieurs Figures.</head> <head xml:id="echoid-head10" xml:space="preserve"><emph style="sc">De’finition</emph>.</head> <p> <s xml:id="echoid-s353" xml:space="preserve">IL y a dans tous les corps peſans, c’eſt-à-dire, dans toutes les <lb/>Figures peſantes, un point par lequel cette Figure étant ſuſpen-<lb/>duë, ou ſoutenuë comme ſur la pointe d’un pivot fort aiguë, toutes <lb/>les parties de la Figure demeurent en équilibre ou en repos, or <lb/>ce point eſt nommé le centre de gravité de la Figure.</s> <s xml:id="echoid-s354" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div9" type="section" level="1" n="9"> <head xml:id="echoid-head11" xml:space="preserve">PROPOSITION PREMIERE.</head> <head xml:id="echoid-head12" xml:space="preserve"><emph style="sc">The’oreme</emph>.</head> <p style="it"> <s xml:id="echoid-s355" xml:space="preserve">1. </s> <s xml:id="echoid-s356" xml:space="preserve">Si l’on diviſe en deux également les côtés opoſés AB, & </s> <s xml:id="echoid-s357" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0027-01a" xlink:href="note-0027-01"/> CD, d’un Paralellograme, & </s> <s xml:id="echoid-s358" xml:space="preserve">qu’on tire la ligne EF, je dis <lb/>que le centre de gravité de ce Paralellograme, eſt dans le <lb/> <anchor type="note" xlink:label="note-0027-02a" xlink:href="note-0027-02"/> milieu de cette ligne.</s> <s xml:id="echoid-s359" xml:space="preserve"/> </p> <div xml:id="echoid-div9" type="float" level="2" n="1"> <note position="right" xlink:label="note-0027-01" xlink:href="note-0027-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>1.</note> <note position="right" xlink:label="note-0027-02" xlink:href="note-0027-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 1.</note> </div> </div> <div xml:id="echoid-div11" type="section" level="1" n="10"> <head xml:id="echoid-head13" xml:space="preserve"><emph style="sc">Demonstration</emph>.</head> <p> <s xml:id="echoid-s360" xml:space="preserve">Il eſt certain que la ligne EF, paſſant par le milieu de tous les <lb/>élemens qui compoſent le Paralellograme, leur centre commun de <lb/>gravité ſera dans un des points de cette ligne; </s> <s xml:id="echoid-s361" xml:space="preserve">de même ſi par le <lb/>milieu des côtés AC, & </s> <s xml:id="echoid-s362" xml:space="preserve">BD, on tire la ligne GH, le centre de <lb/>gravité du Paralellograme ſera auſſi dans cette ligne GH, il ſera <lb/>donc au point I, où ces deux lignes ſe rencontrent. </s> <s xml:id="echoid-s363" xml:space="preserve">C. </s> <s xml:id="echoid-s364" xml:space="preserve">Q. </s> <s xml:id="echoid-s365" xml:space="preserve">F. </s> <s xml:id="echoid-s366" xml:space="preserve">D.</s> <s xml:id="echoid-s367" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div12" type="section" level="1" n="11"> <head xml:id="echoid-head14" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s368" xml:space="preserve">2. </s> <s xml:id="echoid-s369" xml:space="preserve">Quoique l’on ait coutume de conſiderer un Plan ſans nulle <lb/>épaiſſeur, quand il s’agit de la ſuperficie des corps, cela n’empêche <lb/>pas qu’on ne puiſſe attribuer une peſanteur aux Plans dont nous <lb/>parlons, ſans que pour cela il faille leur ſupoſer une épaiſſeur ſen-<lb/>ſible: </s> <s xml:id="echoid-s370" xml:space="preserve">cependant comme cette peſanteur ne peut être meſurée par <lb/>aucun poids, nous regarderons la valeur de la ſuperficie des Plans, <pb o="6" file="0028" n="28" rhead="LA SCIENCE DES INGENIEURS,"/> comme tenant lieu de la peſanteur qui entre dans la Mécanique <lb/>dont nous parlons; </s> <s xml:id="echoid-s371" xml:space="preserve">ainſi on peut imaginer que deux Plans homo-<lb/>genes ſont en équilibre aux extrêmités des bras d’un levier, quand <lb/>les ſuperficies de ces Plans ſont dans la raiſon réciproque des bras <lb/>du levier.</s> <s xml:id="echoid-s372" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div13" type="section" level="1" n="12"> <head xml:id="echoid-head15" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s373" xml:space="preserve">3. </s> <s xml:id="echoid-s374" xml:space="preserve">Puiſque l’on peut conſiderer la ſuperficie d’un Plan comme <lb/>exprimant la peſanteur qu’on lui attribuë, on pourra donc, comme <lb/>dans la Mécanique ordinaire, ſupoſer toute la peſanteur du Plan; <lb/></s> <s xml:id="echoid-s375" xml:space="preserve">c’eſt-à-dire, ſa ſuperficie réünie autour d’un point pris à volonté <lb/>dans la ligne de direction qui paſſera par le centre de gravité; </s> <s xml:id="echoid-s376" xml:space="preserve">par <lb/>exemple, nommant a, la hauteur AC, du Paralellograme; </s> <s xml:id="echoid-s377" xml:space="preserve">& </s> <s xml:id="echoid-s378" xml:space="preserve">b, <lb/> <anchor type="note" xlink:label="note-0028-01a" xlink:href="note-0028-01"/> la baſe CD; </s> <s xml:id="echoid-s379" xml:space="preserve">ſa ſuperficie ſera ab; </s> <s xml:id="echoid-s380" xml:space="preserve">or ſi on la ſupoſe réünie <lb/>dans le poids K, qui eſt dans un des points de la ligne I L, tiree <lb/>du centre de gravité I, l’on poura donc dire que la peſanteur de <lb/>ce poids eſt exprimée par ab.</s> <s xml:id="echoid-s381" xml:space="preserve"/> </p> <div xml:id="echoid-div13" type="float" level="2" n="1"> <note position="left" xlink:label="note-0028-01" xlink:href="note-0028-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 1.</note> </div> </div> <div xml:id="echoid-div15" type="section" level="1" n="13"> <head xml:id="echoid-head16" style="it" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s382" xml:space="preserve">4. </s> <s xml:id="echoid-s383" xml:space="preserve">Comme les Plans, dont il ſera queſtion, repréſenteront des <lb/>profils de Maçonnerie ou de Terraſſe, il faudra avoir égard, non-<lb/>ſeulement à leur ſuperficie quand ils tiendront lieu d’une puiſſance <lb/>ou d’un poids, mais encore à la nature des corps dont ils ſeront <lb/>la coupe, par exemple ſi on a un levier dont le point d’apui ſoit <lb/>dans le milieu, & </s> <s xml:id="echoid-s384" xml:space="preserve">qu’un Plan de ſix pieds quarrés, provenant d’une <lb/>coupe de Maçonnerie, ſoit ſuſpendu à l’extrémité d’un des bras; <lb/></s> <s xml:id="echoid-s385" xml:space="preserve">on ne peut pas dire que ce Plan puiſſe ſe mettre en équilibre avec <lb/>un autre de ſix pieds quarrés provenant d’une coupe de terre, <lb/>parce qu’un pied cube de Maçonnerie peſant davantage qu’un pied <lb/>cube de terre, il faut s’imaginer que le premier Plan péſe davan-<lb/>tage que le ſecond, dans la raiſon qu’un pied cube de Maçonnerie <lb/>péſe plus qu’un pied cube de terre; </s> <s xml:id="echoid-s386" xml:space="preserve">or comme nous avons be-<lb/>ſoin de connoître ce rapport, parce qu’il aura lieu dans cette Mé-<lb/>canique, l’on ſaura que le poids d’un certain voulume de Maçon-<lb/>nerie eſt à celui d’un pareil volume de terre, à peu-près comme <lb/>3 eſt à 2, c’eſt-à-dire, que la terre peſe moins d’un tiers que la <lb/>Maçonnerie.</s> <s xml:id="echoid-s387" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div16" type="section" level="1" n="14"> <head xml:id="echoid-head17" style="it" xml:space="preserve">Remarque quatriéme.</head> <p> <s xml:id="echoid-s388" xml:space="preserve">5. </s> <s xml:id="echoid-s389" xml:space="preserve">Si l’on avoit donc une puiſſance repréſentée par un nombre <pb o="7" file="0029" n="29" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> de pieds quarrés provenant d’un profil de terre, qu’on voulut met-<lb/>tre en équilibre avec un poids provenant d’un profil de Maçonne-<lb/>rie, il faudra prendre les deux tiers de la puiſſance, afin de la ren-<lb/>dre homogene à la Maçonnerie; </s> <s xml:id="echoid-s390" xml:space="preserve">car comme la terre péſe moins <lb/>d’un tiers que la Maçonnerie, on ne pourra jamais faire avec ces <lb/>deux matieres differentes des rapports de poids à poids, qu’on ne <lb/>faſſe une réduction dans le volume de la plus légere.</s> <s xml:id="echoid-s391" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div17" type="section" level="1" n="15"> <head xml:id="echoid-head18" xml:space="preserve">PROPOSITION SECONDE.</head> <head xml:id="echoid-head19" xml:space="preserve"><emph style="sc">The’oreme</emph>.</head> <p style="it"> <s xml:id="echoid-s392" xml:space="preserve">6. </s> <s xml:id="echoid-s393" xml:space="preserve">Si l’on a un triangle A B C, quelconque, & </s> <s xml:id="echoid-s394" xml:space="preserve">que l’on <lb/> <anchor type="note" xlink:label="note-0029-01a" xlink:href="note-0029-01"/> diviſe la baſe A C, en deux également au point D, je dis <lb/>que le centre de gravité de ce triangle ſera dans le tiers de <lb/>la ligne B D, menée de l’angle B, au milieu de la baſe A C, <lb/>qui lui eſt opoſée.</s> <s xml:id="echoid-s395" xml:space="preserve"/> </p> <div xml:id="echoid-div17" type="float" level="2" n="1"> <note position="right" xlink:label="note-0029-01" xlink:href="note-0029-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 2.</note> </div> </div> <div xml:id="echoid-div19" type="section" level="1" n="16"> <head xml:id="echoid-head20" xml:space="preserve"><emph style="sc">Demonstration</emph>.</head> <p> <s xml:id="echoid-s396" xml:space="preserve">Pour le prouver, je diviſe le côtê BC, en deux également au <lb/>point E; </s> <s xml:id="echoid-s397" xml:space="preserve">& </s> <s xml:id="echoid-s398" xml:space="preserve">de l’angle A, qui lui eſt opoſé, je tire la ligne AE, <lb/>enſuite je prolonge le côté BA, indéfiniment, & </s> <s xml:id="echoid-s399" xml:space="preserve">des points D & </s> <s xml:id="echoid-s400" xml:space="preserve"><lb/>C, je mene à la ligne AE, les paralelles DG, & </s> <s xml:id="echoid-s401" xml:space="preserve">CH, cette pre-<lb/>paration étant faite; </s> <s xml:id="echoid-s402" xml:space="preserve">conſiderés que ſi l’on ſupoſe le triangle ABC, <lb/>compoſé d’une infinité d’élemens paralelles à la baſe AC, la ligne <lb/>BD, les diviſera tous en deux également; </s> <s xml:id="echoid-s403" xml:space="preserve">& </s> <s xml:id="echoid-s404" xml:space="preserve">qu’ainſi le centre <lb/>commun de péſanteur de la ſomme de tous ces élemens ſera dans <lb/>l’un des points de la ligne BD; </s> <s xml:id="echoid-s405" xml:space="preserve">de même ſupoſant encore le trian-<lb/>gle ABC, compoſé d’une infinité d’élemens paralelles au côté <lb/>BC, la ligne AE, les partageant en deux également, le centre de <lb/>péſanteur de toute leur ſomme ſera encore dans l’un des points <lb/>de la ligne AE; </s> <s xml:id="echoid-s406" xml:space="preserve">or puiſque le centre de gravité de tous les éle-<lb/>mens du triangle de quelque ſens qu’on puiſſe les prendre, eſt <lb/>d’une part dans la ligne BD, & </s> <s xml:id="echoid-s407" xml:space="preserve">de l’autre dans la ligne AE, le <lb/>centre de gravité du triangle ſera donc au point F, où ces deux <lb/>lignes ſe coupent; </s> <s xml:id="echoid-s408" xml:space="preserve">ainſi il faut faire voir préſentement que le <lb/>point F, eſt éloigné de D, du tiers de la ligne BD.</s> <s xml:id="echoid-s409" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s410" xml:space="preserve">Pour cela remarqués en premier lieu, que dans le triangle BHC, <lb/>le côté BC, eſt diviſé en deux également au point E, & </s> <s xml:id="echoid-s411" xml:space="preserve">que la <lb/>ligne AE, étant paralelle à HC, le côté BH, ſera auſſi diviſé <pb o="8" file="0030" n="30" rhead="LA SCIENCE DES INGENIEURS,"/> également au point A; </s> <s xml:id="echoid-s412" xml:space="preserve">en ſecond lieu, que dans le triangle AHC, <lb/>le côté AC, eſt diviſé en deux également au point D; </s> <s xml:id="echoid-s413" xml:space="preserve">que DG, <lb/>etant paralelle à CH, le côté AH, ſera encore diviſé en deux éga-<lb/>lement au point G; </s> <s xml:id="echoid-s414" xml:space="preserve">or la ligne AG, étant moitié de AH, elle ſe-<lb/>ra auſſi moitié de AB, puiſque nous avons prouvé que AB, étoit <lb/>égal à AH, ainſi AG, ſera le tiers de BG, mais comme dans le <lb/>triangle BGD, AF, eſt paralelle à GD, il s’enſuit donc que la <lb/>ligne AG, étant le tiers de BG, la ligne FD, ſera le tiers de BD. <lb/></s> <s xml:id="echoid-s415" xml:space="preserve">C. </s> <s xml:id="echoid-s416" xml:space="preserve">Q. </s> <s xml:id="echoid-s417" xml:space="preserve">F. </s> <s xml:id="echoid-s418" xml:space="preserve">D.</s> <s xml:id="echoid-s419" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div20" type="section" level="1" n="17"> <head xml:id="echoid-head21" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s420" xml:space="preserve">7. </s> <s xml:id="echoid-s421" xml:space="preserve">Pour appliquer ceci au triangle rectangle, qui eſt celui dont <lb/>nous nous ſervirons le plus ordinairement dans la ſuite, remar-<lb/>qués ſelon le théoreme précédent, qu’ayant diviſé la baſe BC, <lb/> <anchor type="note" xlink:label="note-0030-01a" xlink:href="note-0030-01"/> en deux également au point D: </s> <s xml:id="echoid-s422" xml:space="preserve">(car nous prenons ici un des <lb/>petits côtés pour la baſe:) </s> <s xml:id="echoid-s423" xml:space="preserve">& </s> <s xml:id="echoid-s424" xml:space="preserve">tiré la ligne AD, le point E, qui eſt <lb/>au tiers de cette ligne, ſera le centre de gravité du triangle rectan-<lb/>gle ABC, or ſi de ce point l’on abaiſſe la perpendiculaire EF, ſur <lb/>la baſe BC, elle ſera la ligne de direction qui paſſe par le centre <lb/>de gravité; </s> <s xml:id="echoid-s425" xml:space="preserve">mais ED, étant le tiers de AD, DF, ſera le tiers de <lb/>BD, à cauſe des paralelles EF, & </s> <s xml:id="echoid-s426" xml:space="preserve">AB; </s> <s xml:id="echoid-s427" xml:space="preserve">ainſi FD, ſera la ſixiéme <lb/>partie de la baſe BC, & </s> <s xml:id="echoid-s428" xml:space="preserve">la ligne BF, étant double de FD, elle <lb/>ſera par conſequent les deux ſixiémes, ou ce qui eſt la même <lb/>choſe, le tiers de la baſe BC; </s> <s xml:id="echoid-s429" xml:space="preserve">l’on peut donc dire que dans un <lb/>triangle rectangle, la ligne de direction EG, qui paſſe par le centre <lb/>de gravité, paſſe auſſi par le tiers de la baſe BC.</s> <s xml:id="echoid-s430" xml:space="preserve"/> </p> <div xml:id="echoid-div20" type="float" level="2" n="1"> <note position="left" xlink:label="note-0030-01" xlink:href="note-0030-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> </div> <div xml:id="echoid-div22" type="section" level="1" n="18"> <head xml:id="echoid-head22" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s431" xml:space="preserve">8. </s> <s xml:id="echoid-s432" xml:space="preserve">Si l’on avoit un triangle rectangle, & </s> <s xml:id="echoid-s433" xml:space="preserve">qu’on voulut réunir toute <lb/>ſa peſanteur, c’eſt-à-dire, ſa ſuperficie dans un des points de la li-<lb/>gne de direction, il n’y auroit qu’à diviſer la baſe BC, en trois <lb/>parties égales, & </s> <s xml:id="echoid-s434" xml:space="preserve">de l’extrémité F, du tiers qui répond à l’angle <lb/>droit, abaiſſer une perpendiculaire FG, elle ſera la ligne de di-<lb/>rection que l’on demande; </s> <s xml:id="echoid-s435" xml:space="preserve">ainſi nommant a, la hauteur AB, <lb/>du triangle; </s> <s xml:id="echoid-s436" xml:space="preserve">& </s> <s xml:id="echoid-s437" xml:space="preserve">b, la baſe BC; </s> <s xml:id="echoid-s438" xml:space="preserve">l’on aura {ab/2} pour la valeur du <lb/>poids H, dans lequel on ſupoſe que l’on a réüni la péſanteur, ou <lb/>ce qui eſt la même choſe, la ſuperficie du triangle.</s> <s xml:id="echoid-s439" xml:space="preserve"/> </p> <pb o="9" file="0031" n="31" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div23" type="section" level="1" n="19"> <head xml:id="echoid-head23" xml:space="preserve">PROPOSITION TROISIE’ME.</head> <head xml:id="echoid-head24" xml:space="preserve"><emph style="sc">The’oreme</emph>.</head> <p style="it"> <s xml:id="echoid-s440" xml:space="preserve">9. </s> <s xml:id="echoid-s441" xml:space="preserve">Si l’on a un Trapezoïde ABCD, & </s> <s xml:id="echoid-s442" xml:space="preserve">que par le milieu <lb/> <anchor type="note" xlink:label="note-0031-01a" xlink:href="note-0031-01"/> O, & </s> <s xml:id="echoid-s443" xml:space="preserve">E, des côtés paralelles BC, & </s> <s xml:id="echoid-s444" xml:space="preserve">AD, l’on tire la ligne <lb/>OE, je dis que ſi l’on diviſe cette ligne en trois parties égales <lb/>par les points F & </s> <s xml:id="echoid-s445" xml:space="preserve">G, le centre de gravité du Trapezoïde ſera <lb/>dans l’un des points de la partie du milieu FG.</s> <s xml:id="echoid-s446" xml:space="preserve"/> </p> <div xml:id="echoid-div23" type="float" level="2" n="1"> <note position="right" xlink:label="note-0031-01" xlink:href="note-0031-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> </div> <div xml:id="echoid-div25" type="section" level="1" n="20"> <head xml:id="echoid-head25" xml:space="preserve"><emph style="sc">Demonstration</emph>.</head> <p> <s xml:id="echoid-s447" xml:space="preserve">Si du point E, l’on mene les lignes EB, & </s> <s xml:id="echoid-s448" xml:space="preserve">EC, la figure ſera <lb/>diviſée en trois triangles BEC, ABE, & </s> <s xml:id="echoid-s449" xml:space="preserve">ECD, or ſi par le point <lb/>G, l’on mene la ligne HI, paralelle à AD, & </s> <s xml:id="echoid-s450" xml:space="preserve">qu’on diviſe les <lb/>baſes AE, & </s> <s xml:id="echoid-s451" xml:space="preserve">ED, en deux également aux points M, & </s> <s xml:id="echoid-s452" xml:space="preserve">N, pour <lb/>tirer les lignes BM, & </s> <s xml:id="echoid-s453" xml:space="preserve">CN; </s> <s xml:id="echoid-s454" xml:space="preserve">il eſt conſtant quela paralelle HI, qui <lb/>paſſera par le tiers de la ligne BM, & </s> <s xml:id="echoid-s455" xml:space="preserve">CN, donnera les points K, <lb/>& </s> <s xml:id="echoid-s456" xml:space="preserve">L, qui ſeront les centres de gravité destriangles ABE, & </s> <s xml:id="echoid-s457" xml:space="preserve">ECD, <lb/>par l’article 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s458" xml:space="preserve">Mais ces triangles ſont égaux, puiſqu’ils ont la <lb/>même hauteur & </s> <s xml:id="echoid-s459" xml:space="preserve">des baſes égales, leur centre commun de gravité <lb/>ſera donc dans le milieu de la ligne KL, par conſequent au point <lb/>G. </s> <s xml:id="echoid-s460" xml:space="preserve">D’autre côté le centre de gravité du triangle BEC, eſt aupoint <lb/>F, puiſque la ligne OF, eſt le tiers de OE, il s’enſuit donc que le <lb/>centre commun de gravité de ce triangle & </s> <s xml:id="echoid-s461" xml:space="preserve">des deux autres ABE, <lb/>& </s> <s xml:id="echoid-s462" xml:space="preserve">ECD, joints enſemble; </s> <s xml:id="echoid-s463" xml:space="preserve">c’eſt-à-dire, du Trapezoïde; </s> <s xml:id="echoid-s464" xml:space="preserve">eſt dans <lb/>l’un des points de la ligne FG. </s> <s xml:id="echoid-s465" xml:space="preserve">C. </s> <s xml:id="echoid-s466" xml:space="preserve">Q. </s> <s xml:id="echoid-s467" xml:space="preserve">F. </s> <s xml:id="echoid-s468" xml:space="preserve">D.</s> <s xml:id="echoid-s469" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div26" type="section" level="1" n="21"> <head xml:id="echoid-head26" xml:space="preserve">PROPOSITION QUATRIE’ME.</head> <head xml:id="echoid-head27" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <head xml:id="echoid-head28" style="it" xml:space="preserve">10. Trouver le centre de gravité d’un Trapezoïde.</head> <p> <s xml:id="echoid-s470" xml:space="preserve">On vient de voir dans le Théoréme précédent que ſi la ligne <lb/> <anchor type="note" xlink:label="note-0031-02a" xlink:href="note-0031-02"/> OE, qui paſſe par le milieu des paralelles BC, & </s> <s xml:id="echoid-s471" xml:space="preserve">AD, étoit divi-<lb/>ſée en trois parties égales, que le centre de gravité de toute la Fi-<lb/>gure ſeroit dans l’un des points de la ligne FG. </s> <s xml:id="echoid-s472" xml:space="preserve">Or pour trouver ce <lb/>point, nous regarderons la ligne FG, comme un lévier aux extré-<lb/>mités duquel ſeroient ſuſpendus deux poids, dont celui de l’extré- <pb o="10" file="0032" n="32" rhead="LA SCIENCE DES INGENIEURS,"/> mité F, ſeroit équivalent au triangle BEC, & </s> <s xml:id="echoid-s473" xml:space="preserve">l’autre de l’extrémité <lb/>G, équivalent à la ſomme des deux triangles ABE, & </s> <s xml:id="echoid-s474" xml:space="preserve">ECD; <lb/></s> <s xml:id="echoid-s475" xml:space="preserve">& </s> <s xml:id="echoid-s476" xml:space="preserve">ſi l’on ſupoſe que le centre de gravité que l’on cherche ſoit au <lb/>point P, il eſt conſtant que dans l’état d’équilibre, il y aura même <lb/>raiſon du triangle ſuſpendu au point F, à la partie GP, que de la <lb/>ſomme des triangles ſuſpendus au point G, à la partie FP, mais <lb/>comme ces trois triangles ont la même hauteur, ils ſeront entr’eux <lb/>comme leurs baſes; </s> <s xml:id="echoid-s477" xml:space="preserve">c’eſt-à-dire, que le triangle BEC, ſera à la <lb/>ſomme des deux triangles ABE, ECD, comme BC, eſt à AD, <lb/>ainſi pour que le point P, ſoit le centre commun de gravité de <lb/>ces trois triangles ou du Trapezoïde, il faut donc que BC, ſoit à <lb/>AD, comme PG, eſt à PF, ce qui fait v<unsure/>oir que pour trouver le <lb/>centre de gravité d’un Trapezoïde, il faut par le milieu des para-<lb/>lelles BC, & </s> <s xml:id="echoid-s478" xml:space="preserve">AD, tirer la ligne OE, la partager en trois parties <lb/>égales, & </s> <s xml:id="echoid-s479" xml:space="preserve">celle du milieu FG, en deux parties FP, PG, qui ſoient <lb/>l’une à l’autre dans la raiſon de AD, à BC, enſorte que la plus <lb/>grande partie, comme FP, réponde au plus petit côté BC, & </s> <s xml:id="echoid-s480" xml:space="preserve">que <lb/>la plus petite, comme PG, réponde au plus grand AD, par exem-<lb/>ple, ſi BC, étoit le tiers ou la moitié de AD, il faudroit que la <lb/>partie PG, fut le tiers ou la moitié de FP.</s> <s xml:id="echoid-s481" xml:space="preserve"/> </p> <div xml:id="echoid-div26" type="float" level="2" n="1"> <note position="right" xlink:label="note-0031-02" xlink:href="note-0031-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> <p> <s xml:id="echoid-s482" xml:space="preserve">Comme il ſuffit de ſavoir trouver le centre de gravité des Fi-<lb/>gures précédentes pour ce que nous avons à enſeigner dans ce Li-<lb/>vre-ci, je ne parlerai point de ceux des autres Figures, comme <lb/>de portions de Cercles, d’Ellipſe, &</s> <s xml:id="echoid-s483" xml:space="preserve">c. </s> <s xml:id="echoid-s484" xml:space="preserve">Parce que nous ferons en-<lb/>ſorte de nous en paſſer, n’ayant pas voulu les donner, à cauſe que <lb/>les démonſtrations de ces Problémes ſont extrémement longues par <lb/>la Géométrie ordinaire, & </s> <s xml:id="echoid-s485" xml:space="preserve">que ſi j’avois eû recours aux méthodes <lb/>que ſourniſſent pour cela les nouveaux calculs, je me ſerois ex-<lb/>poſé à n’être entendu que de très-peu de perſonnes, ces calculs <lb/>n’étant connus que des Géomêtres du premier ordre.</s> <s xml:id="echoid-s486" xml:space="preserve"/> </p> <figure> <image file="0032-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0032-01"/> </figure> <pb o="11" file="0033" n="33" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div28" type="section" level="1" n="22"> <head xml:id="echoid-head29" xml:space="preserve">CHAPITRE SECOND.</head> <p style="it"> <s xml:id="echoid-s487" xml:space="preserve">Où l’on enſeigne comme on trouve l’épaiſſeur des Murs que l’on <lb/>veut mettre en équilibre par leur réſiſtance, avec les puiſ-<lb/>ſances qui agiroient pour les renverſer lorſque ces Murs <lb/>ſont élevés à plomb des deux côtés.</s> <s xml:id="echoid-s488" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div29" type="section" level="1" n="23"> <head xml:id="echoid-head30" xml:space="preserve">PROPOSITION PREMIERE.</head> <p style="it"> <s xml:id="echoid-s489" xml:space="preserve">Tirée des principes de la Mécanique, & </s> <s xml:id="echoid-s490" xml:space="preserve">qui doit ſervir <lb/>de Lemme à quelques-unes des Propoſitions qu’on rencon-<lb/>trera dans la ſuite.</s> <s xml:id="echoid-s491" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s492" xml:space="preserve">11. </s> <s xml:id="echoid-s493" xml:space="preserve">SI l’on a un lévier ou une balance AB, ſans péſanteur, dont <lb/> <anchor type="note" xlink:label="note-0033-01a" xlink:href="note-0033-01"/> le point d’apui ſoit en C, & </s> <s xml:id="echoid-s494" xml:space="preserve">qu’il y ait à l’extrêmité A, un <lb/>poids M, & </s> <s xml:id="echoid-s495" xml:space="preserve">au point B, une puiſſance P, en équilibre avec <lb/>ce poids; </s> <s xml:id="echoid-s496" xml:space="preserve">on demande de tranſpoſer cette puiſſance à l’extrémité D, <lb/>du bras de lévier CD, plus grand que CB, enſorte qu’elle ſoit en-<lb/>core en équilibre.</s> <s xml:id="echoid-s497" xml:space="preserve"/> </p> <div xml:id="echoid-div29" type="float" level="2" n="1"> <note position="right" xlink:label="note-0033-01" xlink:href="note-0033-01a" xml:space="preserve"><emph style="sc">Fif</emph>. 5.</note> </div> <p> <s xml:id="echoid-s498" xml:space="preserve">L’on ſent bien que cette puiſſance agiſſant en D, n’aura pas <lb/> <anchor type="note" xlink:label="note-0033-02a" xlink:href="note-0033-02"/> beſoin d’une ſr grande force qu’elle avoit en B, pour faire le même <lb/>effet ſur le poids M, puiſque ſon action doit diminuer à meſure <lb/>que le lévier augmente, or pour qu’elle faſſe le même effet à l’ex-<lb/>trémité D, qu’à l’extrémité B, il faut que multipliant la force <lb/>qu’elle a en B, par le bras de lévier CB, l’on ait un produit égal <lb/>à celui de la multiplication du bras de lévier CD, par l’effort qu’il <lb/>faut qu’elle faſſe en D, nommant x, ce ſecond effort; </s> <s xml:id="echoid-s499" xml:space="preserve">c, le bras <lb/>CB; </s> <s xml:id="echoid-s500" xml:space="preserve">& </s> <s xml:id="echoid-s501" xml:space="preserve">b, le bras CD; </s> <s xml:id="echoid-s502" xml:space="preserve">l’on aura cb = bx ou bien {cp/b} = x; </s> <s xml:id="echoid-s503" xml:space="preserve">c’eſt-<lb/>à-dire que pour avoir la force avec laquelle elle agira en D, il faut <lb/>multiplier celle qu’elle avoit en B, par le bras de levier CB, & </s> <s xml:id="echoid-s504" xml:space="preserve"><lb/>diviſer le produit par toute la longueur CD, & </s> <s xml:id="echoid-s505" xml:space="preserve">le quotient ſera <lb/>ce que l’on demande.</s> <s xml:id="echoid-s506" xml:space="preserve"/> </p> <div xml:id="echoid-div30" type="float" level="2" n="2"> <note position="right" xlink:label="note-0033-02" xlink:href="note-0033-02a" xml:space="preserve">Voyez le <lb/>Cours de <lb/>Mathe-<lb/>matiq. art. <lb/>195.</note> </div> <p> <s xml:id="echoid-s507" xml:space="preserve">Mais ſi le bras de lévier au lieu d’être ſur un ſeul alignement <lb/>ACB, faiſoit un angle comme font ceux du lévier recourbé ABC; <lb/></s> <s xml:id="echoid-s508" xml:space="preserve"> <anchor type="note" xlink:label="note-0033-03a" xlink:href="note-0033-03"/> il faudroit s’y prendre de la même facon pour tranſpoſer la puiſ-<lb/>ſance; </s> <s xml:id="echoid-s509" xml:space="preserve">c’eſt-à-dire, que ſi la puiſſance F, eſt apliquée à l’extrémité <lb/>E, du bras EB, où elle agit ſelon une direction perpendiculaire <pb o="12" file="0034" n="34" rhead="LA SCIENCE DES INGENIEURS,"/> EF, & </s> <s xml:id="echoid-s510" xml:space="preserve">que l’on veüille la tranſpoſer à l’extrémité A, du lévier <lb/>AB, plus grand que EB, il faudra multiplier la force de cette puiſ-<lb/>fance par le bras EB, & </s> <s xml:id="echoid-s511" xml:space="preserve">diviſer le produit par le bras AB, pour <lb/>avoir le quotient, qui ſera la force de la puiſſance G, pour qu’é-<lb/>tant apliquée en A, elle faſſe le même effet qu’en E, en ſupo-<lb/>ſant toujours qu’elle agit ſelon une direction perpendiculaire au <lb/>bras du lévier.</s> <s xml:id="echoid-s512" xml:space="preserve"/> </p> <div xml:id="echoid-div31" type="float" level="2" n="3"> <note position="right" xlink:label="note-0033-03" xlink:href="note-0033-03a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> </div> <div xml:id="echoid-div33" type="section" level="1" n="24"> <head xml:id="echoid-head31" style="it" xml:space="preserve">Avertiſſement.</head> <p> <s xml:id="echoid-s513" xml:space="preserve">Avant d’entrer en matiere, il eſt bon de faire ici trois ſupoſi-<lb/>tions, dont on conviendra aiſément dans le ſujet que je vais traiter.</s> <s xml:id="echoid-s514" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s515" xml:space="preserve">12. </s> <s xml:id="echoid-s516" xml:space="preserve">La premiere eſt que l’on doit regarder un Mur comme <lb/>étant aſſis ſur des fondemens inébranlables, & </s> <s xml:id="echoid-s517" xml:space="preserve">que ſi une puiſſance <lb/>pouſſoit ou tiroit le Mur, ſa baſe pouroit s’incliner ſur les fonde-<lb/>mens, comme feroit, par exemple, un cube ou un paralellepipede <lb/>poſé ſur une table.</s> <s xml:id="echoid-s518" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s519" xml:space="preserve">13. </s> <s xml:id="echoid-s520" xml:space="preserve">La ſeconde, eſt qu’on doit conſiderer un Mur comme <lb/>compoſé d’une ſeule pierre; </s> <s xml:id="echoid-s521" xml:space="preserve">c’eſt-à-dire, dont les parties ſoient <lb/>ſi bien liées, qu’elles ſoient comme indiſſolubles, quelque effort <lb/>que faſſe la puiſſance qui agit, elle peut bien renverſer le Mur, <lb/>mais non pas le rompre.</s> <s xml:id="echoid-s522" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s523" xml:space="preserve">14. </s> <s xml:id="echoid-s524" xml:space="preserve">La troiſiéme, c’eſt qu’on peut regarder le profil d’un Mur <lb/>comme exprimant le Mur même, car comme un Mur eſt com-<lb/>poſé d’une infinité de Plans paralelles entr’eux & </s> <s xml:id="echoid-s525" xml:space="preserve">perpendiculaires <lb/>à l’horiſon, ce qu’on dira au ſujet d’un de ces Plans, pourra ſe <lb/>dire de même de tous les autres, ainſi la longueur du Mur eſt une <lb/>choſe dont nous ferons abſtraction.</s> <s xml:id="echoid-s526" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s527" xml:space="preserve">La premiere ſupoſition n’a rien d’extraordinaire, puiſqu’on n’y <lb/>ſupoſe aucune choſe qui n’arrive fort ſouvent dans l’execution: <lb/></s> <s xml:id="echoid-s528" xml:space="preserve">les piles des Ponts & </s> <s xml:id="echoid-s529" xml:space="preserve">les Murs qui ſont bâtis ſur Pilotis ſont aſſis <lb/>ſur un plancher qui leur ſert de baſe; </s> <s xml:id="echoid-s530" xml:space="preserve">ainſi dans ce cas-là le Mur <lb/>ne doit être conſideré que depuis la retraite juſqu’au ſommet, & </s> <s xml:id="echoid-s531" xml:space="preserve"><lb/>c’eſt ſur ce pié que nous l’enviſagerons, n’ayant pas jugé à propos <lb/>d’admettre les fondemens dans les calculs que nous ſerons obligés <lb/>de faire, parce que ces fondemens n’ayant point de profondeur <lb/>déterminée, ils n’auroient pû convenir avec la préciſion que nous <lb/>avons tâché de ſuivre.</s> <s xml:id="echoid-s532" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s533" xml:space="preserve">La ſeconde ſupoſition n’a rien non plus qui répugne, puiſque <lb/>dans une Théorie comme celle-ci, il eſt à préſumer que la Ma-<lb/>connerie a été faite avec toutes les attentions poſſibles, d’ailleurs <lb/>le plus ou moins de liaiſon que peuvent cauſer les materiaux bons <pb o="13" file="0035" n="35" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> ou mauvais, n’eſt point une choſe qui apartient à ce Livre-ci. </s> <s xml:id="echoid-s534" xml:space="preserve">Je <lb/>n’expliquerai point la troiſiéme ſupoſition, parce qu’elle eſt aſſés na-<lb/>turelle.</s> <s xml:id="echoid-s535" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s536" xml:space="preserve">J’ajoûterai encore que pour éviter les répetitions inutiles, nous <lb/>ſupoſerons toûjours que les puiſſances dont nous parlerons, pouſ-<lb/>ſent ou tirent ſelon des directions perpendiculaires à la ligne ver-<lb/>ticale qui détermine la hauteur des Murs, excepté dans les occa-<lb/>ſions où on aura ſoin d’avertir du contraire; </s> <s xml:id="echoid-s537" xml:space="preserve">& </s> <s xml:id="echoid-s538" xml:space="preserve">que chacunes de <lb/>ces puiſſances ſeront nommées bf, ſans qu’on doive s’embaraſſer <lb/>au commencement pourquoi l’on prend plûtôt l’expreſſion bf, que <lb/>toute autre pour déſigner la force de la puiſſance, on en verra la <lb/>raiſon dans la ſuite.</s> <s xml:id="echoid-s539" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div34" type="section" level="1" n="25"> <head xml:id="echoid-head32" xml:space="preserve">PROPOSITION SECONDE.</head> <head xml:id="echoid-head33" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s540" xml:space="preserve">15. </s> <s xml:id="echoid-s541" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux Murs qui <lb/>ſont élevés à plomb devant & </s> <s xml:id="echoid-s542" xml:space="preserve">derriere, pour que par leur pé-<lb/>ſanteur ils ſoient en équilibre avec l’effort qu’ils ont a ſoûtenir.</s> <s xml:id="echoid-s543" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s544" xml:space="preserve">Ayant un paralellograme rectangle ABCD, qui repréſente le <lb/> <anchor type="note" xlink:label="note-0035-01a" xlink:href="note-0035-01"/> profil d’un Mur dont la hauteur AB, eſt déterminée, & </s> <s xml:id="echoid-s545" xml:space="preserve">une puiſ-<lb/>ſance P, qui pouſſe ce Mur ſelon une direction KD; </s> <s xml:id="echoid-s546" xml:space="preserve">on demande <lb/>qu’elle épaiſſeur il faudra donner à la baſe BC, pour que ce Mur <lb/>par ſon poids ſoit en équilibre avec l’effort de la puiſſance.</s> <s xml:id="echoid-s547" xml:space="preserve"/> </p> <div xml:id="echoid-div34" type="float" level="2" n="1"> <note position="right" xlink:label="note-0035-01" xlink:href="note-0035-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> <p> <s xml:id="echoid-s548" xml:space="preserve">Comme c’eſt la même choſe à la puiſſance P, de pouſſer de K, <lb/>en D, ou de tirer de A en H, pour renverſer le Mur, nous ſu-<lb/>poſerons qu’à l’extrêmité de la corde AH, qui va paſſer ſur une <lb/>poulie L, on a attaché un poids I, qui eſt équivalent par ſa pé-<lb/>ſanteur à la force de la puiſſance: </s> <s xml:id="echoid-s549" xml:space="preserve">nous ſupoſerons auſſi qu’ayant <lb/>trouvé le centre de gravité F, du paralellograme, on a réüni <lb/>toute ſa ſuperficie dans le poids G, qui eſt ſuſpendu au milieu F, <lb/>de la ligne BC.</s> <s xml:id="echoid-s550" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s551" xml:space="preserve">Cela poſé, il faut conſidérer les lignes AB, & </s> <s xml:id="echoid-s552" xml:space="preserve">BF, qui forment <lb/>l’angle droit ABF, comme le bras d’un lévier recourbé, dont le <lb/>point d’apui eſt à l’angle B, le poids G, à l’extrémité F, du plus <lb/>petit bras BF, & </s> <s xml:id="echoid-s553" xml:space="preserve">la puiſſance dans la direction de la corde AH, <lb/>qui eſt attachée à l’extrémité A, du plus grand bras AB, nous <lb/>nommerons a, le bras AB; </s> <s xml:id="echoid-s554" xml:space="preserve">& </s> <s xml:id="echoid-s555" xml:space="preserve">bf, la valeur de la puiſſance ou du <lb/>poids I; </s> <s xml:id="echoid-s556" xml:space="preserve">la ligne BC, que nous cherchons, ſera nommée y; </s> <s xml:id="echoid-s557" xml:space="preserve">pour <pb o="14" file="0036" n="36" rhead="LA SCIENCE DES INGENIEURS,"/> lors l’on aura ay, pour la ſuperficie du paralellograme, ou ce qui <lb/>eſt la même choſe, pour la valeur du poids G, or il ne s’agit <lb/>donc que de connoître y.</s> <s xml:id="echoid-s558" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s559" xml:space="preserve">Remarqués, que pour que la puiſſance & </s> <s xml:id="echoid-s560" xml:space="preserve">le poids ſoient en équi-<lb/> <anchor type="note" xlink:label="note-0036-01a" xlink:href="note-0036-01"/> libre, il faut qu’ils ſoient dans la raiſon réciproque des bras du <lb/>lévier, & </s> <s xml:id="echoid-s561" xml:space="preserve">comme on ſupoſe ici l’équilibre, l’on aura donc bf, ay:</s> <s xml:id="echoid-s562" xml:space="preserve">: <lb/>{y/2}, a, qui donne abf = {ayy/2} d’où effaçant a, de part & </s> <s xml:id="echoid-s563" xml:space="preserve">d’autre, & </s> <s xml:id="echoid-s564" xml:space="preserve"><lb/>multipliant le premier membre par 2, pour faire évanouïr la frac-<lb/>tion du ſecond, il vient 2bf = yy, qui ſe réduit à cette derniere <lb/>équation √2bf\x{0020} = y.</s> <s xml:id="echoid-s565" xml:space="preserve"/> </p> <div xml:id="echoid-div35" type="float" level="2" n="2"> <note position="left" xlink:label="note-0036-01" xlink:href="note-0036-01a" xml:space="preserve">V. le C. <lb/>art. 494.</note> </div> </div> <div xml:id="echoid-div37" type="section" level="1" n="26"> <head xml:id="echoid-head34" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s566" xml:space="preserve">Pour trouver l’épaiſſeur qu’il faut donner à un Mur qui eſt <lb/>pouſſé par le ſommet ſelon une direction perpendiculaire, il <lb/>faut doubler le nombre qui exprime la valeur de la puiſſance & </s> <s xml:id="echoid-s567" xml:space="preserve">en <lb/>extraire la racine quarrée, cette racine ſera ce que l’on demande, <lb/>par exemple ſupoſant que la puiſſance bf, ſoit équivalente à un <lb/>plan de 18 pieds quarrés, il faut doubler ce nombre pour avoir <lb/>36 pieds quarrès, dont la racine qui eſt 6, ſera l’épaiſſeur BC, <lb/>que l’on cherche.</s> <s xml:id="echoid-s568" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s569" xml:space="preserve">Si j’ai ſupoſé que la puiſſance étoit équivalente à un plan de <lb/>18 pieds quarrés, il ne faut pas que cela paroiſſe extraordinaire, <lb/>puiſque, comme on l’a déja inſinué dans le ſecond article, les forces <lb/>agiſſantes & </s> <s xml:id="echoid-s570" xml:space="preserve">réſiſtantes ne doivent être exprimées dans cette Mé-<lb/>canique qu’avec des plans, comme on en verra encore mieux la <lb/>raiſon ailleurs.</s> <s xml:id="echoid-s571" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div38" type="section" level="1" n="27"> <head xml:id="echoid-head35" xml:space="preserve"><emph style="sc">Corollaire</emph> I.</head> <p> <s xml:id="echoid-s572" xml:space="preserve">16. </s> <s xml:id="echoid-s573" xml:space="preserve">Si l’on avoit un Mur AD, pouſſé par deux puiſſances qui <lb/> <anchor type="note" xlink:label="note-0036-02a" xlink:href="note-0036-02"/> agiſſent ſelon les directions LB, & </s> <s xml:id="echoid-s574" xml:space="preserve">KM, ou qui tirent de l’autre <lb/>côté ſelon les directions AI & </s> <s xml:id="echoid-s575" xml:space="preserve">GH, & </s> <s xml:id="echoid-s576" xml:space="preserve">qu’on veut ſavoir quelle <lb/>épaiſſeur il faudroit donner à ce Mur pour être en équilibre avec <lb/>les deux puiſſances, il faut réünir la puiſſance H, avec la puiſſance <lb/>I, c’eſt-à-dire, la tranſporter à l’extrêmité A, ſelon l’article 11<emph style="sub">e</emph>. <lb/></s> <s xml:id="echoid-s577" xml:space="preserve">& </s> <s xml:id="echoid-s578" xml:space="preserve">ſupoſant que la valeur de ces deux puiſſances ſoit exprimée par <lb/>bf, l’on aura comme cy-devant √2bf\x{0020} = y.</s> <s xml:id="echoid-s579" xml:space="preserve"/> </p> <div xml:id="echoid-div38" type="float" level="2" n="1"> <note position="left" xlink:label="note-0036-02" xlink:href="note-0036-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <pb o="15" file="0037" n="37" rhead="LIVRE I: DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div40" type="section" level="1" n="28"> <head xml:id="echoid-head36" xml:space="preserve"><emph style="sc">Corollaire</emph> II.</head> <p> <s xml:id="echoid-s580" xml:space="preserve">17. </s> <s xml:id="echoid-s581" xml:space="preserve">De même ſi I’on avoit une puiſſance apliquée en E, <lb/> <anchor type="note" xlink:label="note-0037-01a" xlink:href="note-0037-01"/> qui tire de E, en H, & </s> <s xml:id="echoid-s582" xml:space="preserve">une autre aliquée en B, tirant de B, en <lb/>K, & </s> <s xml:id="echoid-s583" xml:space="preserve">qu’on voulut connoitre qu’elle doit être l’épaiſſeur AD, pour <lb/>que le Mur ſoit en équilibre par ſon poids, avec les deux puiſſan-<lb/>ces, en ſupoſant que la puiſſance K, fait beaucoup plus d’effort <lb/>au point B, que la puiſſance H, n’en fait au point E, il faut ré-<lb/>duire la puiſſance H, à l’extrémité C, par l’article 11<emph style="sub">e</emph>. </s> <s xml:id="echoid-s584" xml:space="preserve">pour avoir <lb/>la puiſſance I, qui ſera opoſée à la puiſſance K, ainſi étant ſur <lb/>un même alignement, il ſe fera une deſtruction de force; </s> <s xml:id="echoid-s585" xml:space="preserve">c’eſt-à-<lb/>dire, que la puiſſance K, que nous avons ſupoſée la plus grande <lb/>des deux, ſera diminuée de toute la puiſſance I; </s> <s xml:id="echoid-s586" xml:space="preserve">c’eſt pourquoi ſi <lb/>l’on retranche la plus petite de la plus grande, & </s> <s xml:id="echoid-s587" xml:space="preserve">que l’on nomme <lb/>la difference bf, tout le mécaniſme ſe réduira encore à cette derniere <lb/>équation √2bf\x{0020} = y.</s> <s xml:id="echoid-s588" xml:space="preserve"/> </p> <div xml:id="echoid-div40" type="float" level="2" n="1"> <note position="right" xlink:label="note-0037-01" xlink:href="note-0037-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 16.</note> </div> </div> <div xml:id="echoid-div42" type="section" level="1" n="29"> <head xml:id="echoid-head37" xml:space="preserve"><emph style="sc">Corollaire</emph> III.</head> <p> <s xml:id="echoid-s589" xml:space="preserve">18. </s> <s xml:id="echoid-s590" xml:space="preserve">Ayant un Mur AD, & </s> <s xml:id="echoid-s591" xml:space="preserve">une puiſſance K, apliquée à l’ex-<lb/> <anchor type="note" xlink:label="note-0037-02a" xlink:href="note-0037-02"/> trêmité A du lévier AC, qui tire de A en F, ſelon une direction <lb/>oblique au bras du même lévier, voulant ſavoir quelle épaiſſeur <lb/>il faut donner à la baſe CD, du Mur pour qu’il ſoit en équilibre <lb/>par ſon poids avec l’effort de la puiſſance K; </s> <s xml:id="echoid-s592" xml:space="preserve">conſiderés que le <lb/>poids I, équivalent à cette puiſſance n’aura pas tant de force en <lb/>agiſſant ſelon la direction oblique AF, que ſi c’étoit ſelon une di-<lb/>rection AN, perpendiculaire au lévier AC. </s> <s xml:id="echoid-s593" xml:space="preserve">Or ſi l’on abaiſſe du <lb/>point d’apui C, la perpendiculaire CG, ſur le prolongement FA, <lb/>de la direction de la puiſſance, on pourra au lieu du bras de lévier <lb/>CA, prendre le bras CG, & </s> <s xml:id="echoid-s594" xml:space="preserve">pour lors la propoſition ſubſiſtera toû-<lb/>jours dans ſon entier, puiſque l’on ſait que la puiſſance eſt au poids <lb/>dans la raiſon réciproque des perpendiculaires CG, & </s> <s xml:id="echoid-s595" xml:space="preserve">CL, abaiſſées <lb/> <anchor type="note" xlink:label="note-0037-03a" xlink:href="note-0037-03"/> ſur les lignes de direction de la puiſſance & </s> <s xml:id="echoid-s596" xml:space="preserve">du poids, ainſi nom-<lb/>mant la ligne CA, c; </s> <s xml:id="echoid-s597" xml:space="preserve">le lévier CG, a; </s> <s xml:id="echoid-s598" xml:space="preserve">& </s> <s xml:id="echoid-s599" xml:space="preserve">la baſe CD, y; </s> <s xml:id="echoid-s600" xml:space="preserve">l’on aura <lb/>bf, cy:</s> <s xml:id="echoid-s601" xml:space="preserve">: {y/2}, a, qui donne abf = {cyy/2} ou bien √2abf\x{0020}/c = y.</s> <s xml:id="echoid-s602" xml:space="preserve"/> </p> <div xml:id="echoid-div42" type="float" level="2" n="1"> <note position="right" xlink:label="note-0037-02" xlink:href="note-0037-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 9.</note> <note position="right" xlink:label="note-0037-03" xlink:href="note-0037-03a" xml:space="preserve">V. le C. <lb/>art. 772.</note> </div> </div> <div xml:id="echoid-div44" type="section" level="1" n="30"> <head xml:id="echoid-head38" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s603" xml:space="preserve">Pour avoir l’épaiſſeur CD, il faut multiplier la puiſſance I, par <lb/>le lévier CD, diviſer le produit par la hauteur AC, de la muraille, <lb/>doubler le quotient & </s> <s xml:id="echoid-s604" xml:space="preserve">en extraire la racine quarrée qui donnera ce <lb/>que l’on cherche.</s> <s xml:id="echoid-s605" xml:space="preserve"/> </p> <pb o="16" file="0038" n="38" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div45" type="section" level="1" n="31"> <head xml:id="echoid-head39" xml:space="preserve">CHAPITRE TROISIE’ME.</head> <p style="it"> <s xml:id="echoid-s606" xml:space="preserve">Où l’on détermine quelle épaiſſeur il faut donner au ſommet <lb/>des Murs qui ſont élevés à plomb d’un côté & </s> <s xml:id="echoid-s607" xml:space="preserve">en talud de <lb/>l’autre, pour que ces Murs puiſſent être en équilibre par <lb/>leur reſiſtance, avec la pouſſée qu’ils ont à ſoûtenir.</s> <s xml:id="echoid-s608" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s609" xml:space="preserve">IL y a aparence que dès les premiers tems que les Hommes ſe <lb/>ſont aviſé de faire des revêtemens de Maçonnerie pour ſoûtenir <lb/>des Terraſſes ou des Rempars de Fortification, ils ont ſenti la ne-<lb/>ceſſité de leur donner du talud du côté du parement; </s> <s xml:id="echoid-s610" xml:space="preserve">mais l’on <lb/>ne ſait pas bien s’ils ont eu deſſein de donner plus d’aſſiete à la <lb/>baſe du Mur, ou ſi c’étoit ſeulement pour que les matériaux ſe <lb/>ſoûtiennent mieux, à l’imitation de ce que l’on fait pour les ouvra-<lb/>ges de Terraſſe; </s> <s xml:id="echoid-s611" xml:space="preserve">car il ne paroît pas que leur vûë ait été de rendre <lb/>les revêtemens capables de réſiſter davantage à la pouſſée des terres, <lb/>du moins les Architectes tant anciens que modernes qui ont écrit <lb/>n’en font pas mention; </s> <s xml:id="echoid-s612" xml:space="preserve">& </s> <s xml:id="echoid-s613" xml:space="preserve">ce qui me feroit préſumer qu’ils n’ont <lb/>pas aperçû tout l’avantage des taluds, c’eſt qu’ils ſe ſont conten-<lb/>tés d’établir pour regle générale qu’il falloit donner aux Murs pour <lb/>talud la cinquiéme partie de leur hauteur, & </s> <s xml:id="echoid-s614" xml:space="preserve">que dans bien des <lb/>occaſions où ils auroient pû en donner beaucoup plus pour ne <lb/>point employer une quantité prodigieuſe de matériaux ſuperflus, <lb/>ils ne l’ont pas fait; </s> <s xml:id="echoid-s615" xml:space="preserve">au contraire ſouvent il leur eſt arrivé de don-<lb/>ner du talud à des Murs qui n’en devoient point avoir, & </s> <s xml:id="echoid-s616" xml:space="preserve">d’élever <lb/>à plomb des deux côtés ceux qu’un talud auroit rendu capables d’une <lb/>force beaucoup plus grande, même avec moins de maçonnerie. </s> <s xml:id="echoid-s617" xml:space="preserve">Ce-<lb/>pendant il eſt ſi naturel d’apercevoir qu un Mur qui a du talud ré-<lb/>ſiſte mieux qu’un autre qui n’en à point, que, malgré tout ce que <lb/>je pourrois dire pour confirmer ma penſée, j’aime mieux croire <lb/>qu’ils ont vû que le talud étoit néceſſaire, mais qu’ils n’ont eû là-<lb/>deſſus que des ſentimens obſcurs, ce qui ne peut arriver autrement <lb/>quand on ne conſidere pas les choſes dans leur principe; </s> <s xml:id="echoid-s618" xml:space="preserve">mais <lb/>comme rien, en fait d’Architecture, ne me paroît plus néceſſaire <lb/>d’être bien entendu que ce qui vient de faire le ſujet de cette petite <lb/>Diſſertation, je vais faire enſorte dans ce Chapitre d’en bien déve-<lb/>loper toutes les circonſtances.</s> <s xml:id="echoid-s619" xml:space="preserve"/> </p> <pb o="17" file="0039" n="39" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div46" type="section" level="1" n="32"> <head xml:id="echoid-head40" xml:space="preserve">PROPOSITION PREMIERE.</head> <head xml:id="echoid-head41" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s620" xml:space="preserve">19. </s> <s xml:id="echoid-s621" xml:space="preserve">Ayant un profil de Muraille ABC, triangulaire dont <lb/>le point d’apui eſt en C, & </s> <s xml:id="echoid-s622" xml:space="preserve">qu’une puiſſance pouſſe de K, en <lb/>B, pour la renverſer du côté opoſé, on demande quelle épaiſ-<lb/>ſeur il faudra donner à la baſe AC, pour que le poids G, <lb/>qu’on ſupoſe équivalent à la ſuperficie du triangle, ſoit en <lb/>équilibre avec la puiſſance K.</s> <s xml:id="echoid-s623" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s624" xml:space="preserve">Pour bien entendre ce Probléme, il faut conſiderer les côtés <lb/> <anchor type="note" xlink:label="note-0039-01a" xlink:href="note-0039-01"/> CB, & </s> <s xml:id="echoid-s625" xml:space="preserve">CE, de l’angle BCE, comme formant un lévier recourbé <lb/>dont le point d’apui eſt en C, que la puiſſance K, étant apliquée <lb/>à l’extrêmité B, bu bras CB, pouſſe ſelon une direction paralelle à <lb/>l’horiſon, & </s> <s xml:id="echoid-s626" xml:space="preserve">par conſequent oblique au bras de lévier, & </s> <s xml:id="echoid-s627" xml:space="preserve">que le <lb/>poids G, eſt apliqué à l’extrêmité E, de l’autre bras CE, qui eſt <lb/>terminé par la ligne de direction IL, tirée du centre de gravité I, <lb/>du triangle. </s> <s xml:id="echoid-s628" xml:space="preserve">Or comme c’eſt la même choſe que la puiſſance K, <lb/>pouſſe de K, en B, ou qu’elle tire de B, en H, ſelon une direction toû-<lb/>jours paralelle à l’horiſon, nous ſupoſerons pour plus de facilité que <lb/>le poids F, eſt équivalent à cette puiſſance, & </s> <s xml:id="echoid-s629" xml:space="preserve">abaiſſant la perpendi-<lb/>culaire CD, ſur la ligne BH, la longueur du bras de lévier oblique <lb/>CB, par raport à la puiſſance, ſera réduite à la ligne CD, par l’arti-<lb/>cle 18<emph style="sub">e</emph>, & </s> <s xml:id="echoid-s630" xml:space="preserve">par-làla puiſſance K, ou F, pourra être admiſe dans ſon <lb/>entier, en ſupoſant qu’elle eſt apliquée à l’extrêmité D, de la perpen-<lb/>diculaire CD, que nous regarderons préſentement comme un des <lb/>bras de lévier. </s> <s xml:id="echoid-s631" xml:space="preserve">Sil’on nomme ce bras de lévier, c; </s> <s xml:id="echoid-s632" xml:space="preserve">auſſi-bien que la <lb/>hauteur BA, qui lui eſt égale, y, la baſe CA; </s> <s xml:id="echoid-s633" xml:space="preserve">l’on aura {2y/3} pour l’au-<lb/>tre bras CE, (puiſque par l’article 7<emph style="sub">e</emph> la partie AE, eſt le tiers <lb/>de toute la baſe AC,) cela étant, le poids G, ſera {yc/2}, ainſi l’on <lb/>aura bf, {yc/2} :</s> <s xml:id="echoid-s634" xml:space="preserve">: {2y/3}, c, qui donne cette équation {2yyc/6} = bcf, qu’on <lb/>rendra plus ſimple en faiſant la réduction, puiſqu’on n’aura plus <lb/>que{yy/3} = bf, ou bien y = √3bf,\x{0020} qui fait voir qu’on trouvera la <lb/>baſe AC, en triplant la puiſſance K, ou F, & </s> <s xml:id="echoid-s635" xml:space="preserve">en extrayant la ra-<lb/>cine quarrée de ce produit.</s> <s xml:id="echoid-s636" xml:space="preserve"/> </p> <div xml:id="echoid-div46" type="float" level="2" n="1"> <note position="right" xlink:label="note-0039-01" xlink:href="note-0039-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 15.</note> </div> <pb o="18" file="0040" n="40" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div48" type="section" level="1" n="33"> <head xml:id="echoid-head42" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s637" xml:space="preserve">20. </s> <s xml:id="echoid-s638" xml:space="preserve">L’on doit remarquer ici que de toutes les figures que l’on <lb/>peut donner à un profil de muraille qui a quelque pouſſée à ſoûte-<lb/>nir, il n’y en a point où il faille moins de maçonnerie que dans <lb/>celle qui eſt triangulaire, parce que le lévier CE, gagne par ſa <lb/>longueur ce que le poids G, a de moins provenant d’un triangle, <lb/> <anchor type="note" xlink:label="note-0040-01a" xlink:href="note-0040-01"/> que s’il provenoit d’un paralellograme, ce que je vais démontrer.</s> <s xml:id="echoid-s639" xml:space="preserve"/> </p> <div xml:id="echoid-div48" type="float" level="2" n="1"> <note position="left" xlink:label="note-0040-01" xlink:href="note-0040-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 15.</note> </div> <p> <s xml:id="echoid-s640" xml:space="preserve">Ayant le paralellograme rectangle AD, dont la hauteur ſoit <lb/>égale à celle du triangle précédent, & </s> <s xml:id="echoid-s641" xml:space="preserve">que la puiſſance qui <lb/> <anchor type="note" xlink:label="note-0040-02a" xlink:href="note-0040-02"/> pouſſe de K, en C, ou tire de C, en G, ſelon une direction para-<lb/>lelle à l’horiſon, agiſſe avec la même force que celle du <lb/>triangle ABC, l’on ſait que pour avoir l’épaiſſeur BD, il faut <lb/>doubler la puiſſance K, & </s> <s xml:id="echoid-s642" xml:space="preserve">en extraire la racine quarrée, <anchor type="note" xlink:href="" symbol="*"/> puiſqu’a- <anchor type="note" xlink:label="note-0040-03a" xlink:href="note-0040-03"/> près avoir fait les opérations ordinaires, il vient pour derniere <lb/>équation √2bf\x{0020} = y, & </s> <s xml:id="echoid-s643" xml:space="preserve">comme nous venons d’avoir √3bf\x{0020} = y pour <lb/>la baſe du triangle, l’on peut donc dire que la ſuperficie du profil <lb/>rectangle AD, ſera à celle du profil triangulaire, comme √2bf\x{0020} eſt <lb/>à la moitié de √3bf\x{0020}, puiſque ne prenant que la moitié de la baſe <lb/>du triangle, l’on peut regarder cette moitié comme la baſe du <lb/>rectangle égal au triangle, mais la moitié de √3bf\x{0020} eſt beaucoup <lb/>moindre que √2bf\x{0020}, & </s> <s xml:id="echoid-s644" xml:space="preserve">pour en être convaincu, il n’y a qu’à faire <lb/>un triangle rectangle & </s> <s xml:id="echoid-s645" xml:space="preserve">iſocelle ABC, & </s> <s xml:id="echoid-s646" xml:space="preserve">ſupoſer que chaque quarré <lb/> <anchor type="note" xlink:label="note-0040-04a" xlink:href="note-0040-04"/> des côtés BA, & </s> <s xml:id="echoid-s647" xml:space="preserve">BC, eſt égal à bf, cela étant, l’hypotenuſe AC, <lb/>ou ce qui eſt la même choſe, √2bf\x{0020}, pourra être regardée comme <lb/>exprimant la baſe BD, du profil rectangle, & </s> <s xml:id="echoid-s648" xml:space="preserve">ſi l’on fait un autre <lb/>triangle rectangle ACD, dont le côté CD, ſoit égal à CB, l’hy-<lb/>potenuſe AD, exprimera la baſe AC, du profil triangulaire, & </s> <s xml:id="echoid-s649" xml:space="preserve">di-<lb/>viſant cette hypotenuſe en deux également au point E, ſa moitié <lb/>AE, ſera la baſe du paralellograme égal au triangle, ainſi la ſuper-<lb/>ficie du profil rectangle ſurpaſſera autant celle du profil triangulaire, <lb/>que la ligne AC, ſurpaſſe la moitié de la ligne AD, ce que l’on ne <lb/>peut pas exprimer en nombre bien exactement à cauſe des incom-<lb/>menſurables, cependant on peut dire que la maçonnerie du profil <lb/>triangulaire eſt à celle du profil rectangle, à peu-près comme 11. <lb/></s> <s xml:id="echoid-s650" xml:space="preserve">à 18. </s> <s xml:id="echoid-s651" xml:space="preserve">ce qui fait voir qu’il y a plus d’un tiers moins dans le pre-<lb/>mier que dans le ſecond.</s> <s xml:id="echoid-s652" xml:space="preserve"/> </p> <div xml:id="echoid-div49" type="float" level="2" n="2"> <note position="left" xlink:label="note-0040-02" xlink:href="note-0040-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 10.</note> <note symbol="*" position="left" xlink:label="note-0040-03" xlink:href="note-0040-03a" xml:space="preserve">Art. 15.</note> <note position="left" xlink:label="note-0040-04" xlink:href="note-0040-04a" xml:space="preserve"><emph style="sc">Fig</emph>. 14.</note> </div> <p> <s xml:id="echoid-s653" xml:space="preserve">Il ne faut pas trouver étrange qu’on ſupoſe ici un profil triangu-<lb/>laire, nous ſavons bien qu’on ne fait pas de Mur qui ſoit terminé <pb o="19" file="0041" n="41" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> en arrête comme eſt celui-ci, c’eſt pourquoi on ne doit regarder <lb/>cette propoſition que comme pouvant ſervir à l’intelligence des <lb/>autres.</s> <s xml:id="echoid-s654" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div51" type="section" level="1" n="34"> <head xml:id="echoid-head43" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s655" xml:space="preserve">21. </s> <s xml:id="echoid-s656" xml:space="preserve">Selon la Remarque précédente, l’on voit combien il eſt de <lb/>conſéquence d’avoir égard à la longueur des léviers pour régler <lb/>l’épaiſſeur des Murs qu’on veut mettre en équilibre avec l’effort <lb/>qu’ils ont à ſoûtenir, & </s> <s xml:id="echoid-s657" xml:space="preserve">que voici la ſeule voïe par laquelle on <lb/>peut connoître ce point d’équilibre. </s> <s xml:id="echoid-s658" xml:space="preserve">C’eſt à quoi Mr. </s> <s xml:id="echoid-s659" xml:space="preserve">Bullet & </s> <s xml:id="echoid-s660" xml:space="preserve">plu-<lb/>ſieurs autres n’ont fait aucune attention dans les régles qu’ils ont <lb/>crû donner ſur ce ſujet, auſſi ſont-ils tombés dans des erreurs fort <lb/>groſſieres.</s> <s xml:id="echoid-s661" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div52" type="section" level="1" n="35"> <head xml:id="echoid-head44" xml:space="preserve">PROPOSITION SECONDE. <lb/><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s662" xml:space="preserve">22. </s> <s xml:id="echoid-s663" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner au ſommet des <lb/>Murs qui ſont élevés à plomb d’un côté & </s> <s xml:id="echoid-s664" xml:space="preserve">qui ont un talud <lb/>de l’autre, pour être en équilibre par leur reſiſtance avec <lb/>la force de la puiſſance qui voudroit les renverſer.</s> <s xml:id="echoid-s665" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s666" xml:space="preserve">L’on donne, comme nous l’avons dit, pour talud aux Murs des <lb/>Rempars ou des Terraſſes, la cinquiéme partie de leur hauteur; <lb/></s> <s xml:id="echoid-s667" xml:space="preserve"> <anchor type="note" xlink:label="note-0041-01a" xlink:href="note-0041-01"/> c’eſt-à-dire, que ſupoſant BG, de 30 pieds, les lignes BI, & </s> <s xml:id="echoid-s668" xml:space="preserve">GH, <lb/>ſeront chacune de 6 pieds; </s> <s xml:id="echoid-s669" xml:space="preserve">ainſi quand on cherche quelle épaiſ-<lb/>ſeur il faut donner à ces ſortes de Murs, l’on a toûjours le trian-<lb/>gle GBH, connu, & </s> <s xml:id="echoid-s670" xml:space="preserve">le Probléme ne roule plus que ſur l’épaiſſeur <lb/>qu’il faut donner à la partie BD, ou FG, qui étant inconnuë nous <lb/>la nommerons y; </s> <s xml:id="echoid-s671" xml:space="preserve">la hauteur BG, ſera nommée c; </s> <s xml:id="echoid-s672" xml:space="preserve">& </s> <s xml:id="echoid-s673" xml:space="preserve">la ligne de <lb/>talud GH, d; </s> <s xml:id="echoid-s674" xml:space="preserve">cela étant, l’on aura yc, pour la valeur du poids N, & </s> <s xml:id="echoid-s675" xml:space="preserve"><lb/>{cd/2} pour le poids M; </s> <s xml:id="echoid-s676" xml:space="preserve">on peut donc dire que le poids N, eſt ſuſpen-<lb/>du à l’extrémité L, du bras de lévier HL, & </s> <s xml:id="echoid-s677" xml:space="preserve">le poids M, à l’ex-<lb/>trémité P, du bras HP, qui eſt égal aux deux tiers de la baſe GH, <lb/>du triangle par l’article 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s678" xml:space="preserve">Or comme on ne ſe ſervira que du bras <lb/>HL, il faut donc ſelon l’art. </s> <s xml:id="echoid-s679" xml:space="preserve">11e. </s> <s xml:id="echoid-s680" xml:space="preserve">réünir le poids M, au poids N, <lb/>de maniere qu’il ne péſe pas plus en L, qu’il fait en P, ainſi je <lb/>multiplie le poids M, ({cd/2}) par ſon bras de lévier HP, ({2d/3}) <pb o="20" file="0042" n="42" rhead="LA SCIENCE DES INGENIEURS,"/> pour avoir le produit {2cdd/6} ou bien {cdd/3} qu’il faut diviſer par le <lb/>bras HL, ({y + 2d/2}) & </s> <s xml:id="echoid-s681" xml:space="preserve">le quotient {{cdd/3}/{y + 2d/2}} ſera le poids M, apli-<lb/>qué au point L, lequel étant ajoûté avec le poids N, donnera <lb/>N + M, (cy + {{cdd/3}/{y + 2d/2}}) qu’on pourra ſi l’on veut conſiderer <lb/>comme ne faiſant que le ſeul poids O, qu’il faut ſupoſer être <lb/>en équilibre avec la puiſſance K, (bf,) ainſi le produit de la puiſ-<lb/>ſance K, par la perpendiculaire HI, (c,) qui eſt équivalente à <lb/>ſon bras du lévier par l’article 18<emph style="sub">e</emph>. </s> <s xml:id="echoid-s682" xml:space="preserve">ſera égal au produit du poids <lb/>O, par ſon bras de lévier HL, pour lors le premier produit don-<lb/>nera bcf, & </s> <s xml:id="echoid-s683" xml:space="preserve">le ſecond {cyy + 2cdy/2} + {cdd/3}, car il eſt à remarquer <lb/>qu’ayant cy + {{cdd/3}/{y + 2d/2}} à multiplier par {y + 2d/2}, il n’y a que le pre-<lb/>mier terme cy, à multiplier effectivement, puiſque pour le ſecond <lb/>{{cdd/3}/{y + 2d/2}} il ſuffit de ſuprimer tout-à-fait le diviſeur {y + 2d/2} pour que <lb/>la grandeur {cdd/3} ſoit multipliée par le bras de lévier LH, car c’eſt <lb/>multiplier une grandeur par ſon diviſeur que de ne pas la diviſer <lb/>quand elle doit l’être.</s> <s xml:id="echoid-s684" xml:space="preserve"/> </p> <div xml:id="echoid-div52" type="float" level="2" n="1"> <note position="right" xlink:label="note-0041-01" xlink:href="note-0041-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 11.</note> </div> <p> <s xml:id="echoid-s685" xml:space="preserve">Comme les deux produits précédens donnent cette équation <lb/>{cyy + 2cdy/2} + {cdd/3} = {bcf/ }, il ne s’agit plus que d’en dégager l’inconnuë <lb/>y, en faiſant paſſer {cdd/3} du premier membre dans le ſecond, & </s> <s xml:id="echoid-s686" xml:space="preserve">effa-<lb/>cer la lettre c, pour avoir yy + 2dy = 2bf - {2dd/3}, mais comme il <lb/>manque dd, au premier membre pour faire un quarré parfait, <anchor type="note" xlink:href="" symbol="*"/> je l’a- <anchor type="note" xlink:label="note-0042-01a" xlink:href="note-0042-01"/> joûte de part & </s> <s xml:id="echoid-s687" xml:space="preserve">d’autre, & </s> <s xml:id="echoid-s688" xml:space="preserve">il vient yy + 2dy + dd = 2bf - {2dd/3} + dd <lb/>ou bien yy + 2dy + dd = 2bf + {dd/3}, & </s> <s xml:id="echoid-s689" xml:space="preserve">extrayant la racine quarrée de <pb o="21" file="0043" n="43" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> chaque membre l’on a y + d = √2bf + {dd/3}\x{0020}, ou enſin y = √2bf + {dd/3}\x{0020} - d</s> </p> <div xml:id="echoid-div53" type="float" level="2" n="2"> <note symbol="*" position="left" xlink:label="note-0042-01" xlink:href="note-0042-01a" xml:space="preserve">V. le C. <lb/>art. 120.</note> </div> </div> <div xml:id="echoid-div55" type="section" level="1" n="36"> <head xml:id="echoid-head45" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s690" xml:space="preserve">Supoſant que la puiſſance K, de quelque part qu’elle puiſſe ve-<lb/>nir, ſoit exprimée par 52 pieds {1/2}, l’on aura par conſequent bf= 52 {1/2}; <lb/></s> <s xml:id="echoid-s691" xml:space="preserve">or comme la derniere équation que nous avons trouvée montre qu’il <lb/>faut pour avoir l’épaiſſeur BD, doubler la valeur de la puiſſance <lb/>qui donne 105. </s> <s xml:id="echoid-s692" xml:space="preserve">ajoûter à cette quantité lè tiers du quarré de la <lb/>ligne de talud BI, ou GH, & </s> <s xml:id="echoid-s693" xml:space="preserve">cette ligne ayant été ſupoſée 6 pieds, <lb/>ſon quarré ſera 36 dont le tiers eſt 12. </s> <s xml:id="echoid-s694" xml:space="preserve">qui étant ajoûté avec 105, <lb/>donne 117, dont il faut extraire la racine quarrée, que l’on trou-<lb/>vera de 10 pieds 9 pouces 8 lignes qui eſt l’épaiſſeur de la baſe <lb/>FH, de laquelle retranchant la valeur de d, c’eſt-à-dire, la valeur <lb/>de la ligne de talud, l’on aura 4 pieds 9 pouces 8 lignes, qui eſt <lb/>l’épaiſſeur qu’il faut donner au ſommet de la muraille pour être en <lb/>équilibre par ſon poids avec la puiſſance K.</s> <s xml:id="echoid-s695" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s696" xml:space="preserve">Cette propoſition nous ſervira dans le quatriéme Chapitre à trou-<lb/>ver l’épaiſſeur qu’il faut donner au ſommet des Murs des Rempars <lb/>pour être en équilibre avec la pouſſée des Terres.</s> <s xml:id="echoid-s697" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div56" type="section" level="1" n="37"> <head xml:id="echoid-head46" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s698" xml:space="preserve">23. </s> <s xml:id="echoid-s699" xml:space="preserve">Quand on a pluſieurs poids apliques à differens endroits d’un <lb/>bras de lévier, à mettre en équilibre avec une puiſſance, il n’eſt pas <lb/>toûjours néceſſaire de réünir les poids ou de les ſupoſer réünis en <lb/>un ſeul, puiſqu’il ſuffit de les multiplier chacun par le bras de lé-<lb/>vier qui lui répond, c’eſt-à-dire, par la diſtance qu’il y a du point <lb/>d’apui aux endroits où ces poids ſont apliqués, parce que la mul-<lb/>tiplication rétablit ce que la diviſion peut ôter: </s> <s xml:id="echoid-s700" xml:space="preserve">ainſi dans le pro-<lb/>blême précédent, au lieu de multiplier le poids M, par ſon bras <lb/>de lévier HP, & </s> <s xml:id="echoid-s701" xml:space="preserve">diviſer enſuite le produit par le bras HL, pour <lb/>en réünir le quotient au poids L, il auroit ſuffi de multiplier le <lb/>poids M, & </s> <s xml:id="echoid-s702" xml:space="preserve">N, chacun par leur bras de lévier, c’eſt-à-dire par <lb/>leur diſtance au point d’apui, puiſque d’une façon comme de l’au-<lb/>tre on aura toûjours {cyy + 2cdy/2} + {cdd/3} pour l’un des membres de <lb/>l’équation, dont l’autre ſera, comme à l’ordinaire, le produit de la <lb/>puiſſance agiſſante par le bras de levier qui lui répond; </s> <s xml:id="echoid-s703" xml:space="preserve">c’eſt pour- <pb o="22" file="0044" n="44" rhead="LA SCIENCE DES INGENIEURS,"/> quoi dans la ſuite on ſe paſſera autant qu’on le pourra de ces ſortes <lb/>de diviſions pour rendre les opérations moins compoſées.</s> <s xml:id="echoid-s704" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div57" type="section" level="1" n="38"> <head xml:id="echoid-head47" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s705" xml:space="preserve">24. </s> <s xml:id="echoid-s706" xml:space="preserve">On peut s’apercevoir ici combien le talud qu’on donne à <lb/>l’une des faces d’un mur, changeroit la réſiſtance de ce mur, ſi la <lb/>puiſſance au lieu de tirer de B, en K, tiroit de D, en A, pour <lb/>cela il faut chercher le centre commun de gravité des poids M, <lb/>& </s> <s xml:id="echoid-s707" xml:space="preserve">N, qui ſera dans un des points du lévier LP, aux extrêmités <lb/>duquel ces poids ſont ſuſpendus, que l’on apercevra en diviſant la <lb/>ligne LP, au point R, de façon que LR, ſoit à RP, comme le <lb/>poids M, eſt au poids N, mais ces deux poids ſont l’un à l’autre <lb/>comme la moitié de GH, eſt à toute la ligne GF, or conſiderant <lb/>ces deux poids M, & </s> <s xml:id="echoid-s708" xml:space="preserve">N, comme étant réünis dans le ſeul poids <lb/>Q, l’on aura le bras de lévier RH, quand il s’agira du point d’a-<lb/>pui H, & </s> <s xml:id="echoid-s709" xml:space="preserve">le bras de lévier FR, quand le point d’apui ſera ſupoſé <lb/>en F, & </s> <s xml:id="echoid-s710" xml:space="preserve">ſi l’on fait attention que le bras de lévier DF, ala même <lb/>longueur que IH, & </s> <s xml:id="echoid-s711" xml:space="preserve">que le poids Q, ne change point de ſitua-<lb/>tion, l’on verra que la puiſſance qui tire de B, en I, eſt à celle <lb/>qui tire de D, en A, comme le bras HR, eſt au bras FR.</s> <s xml:id="echoid-s712" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div58" type="section" level="1" n="39"> <head xml:id="echoid-head48" style="it" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s713" xml:space="preserve">Il y a encore une Remarque à faire, qui eſt, qu’ayant deux <lb/> <anchor type="note" xlink:label="note-0044-01a" xlink:href="note-0044-01"/> murs AD, & </s> <s xml:id="echoid-s714" xml:space="preserve">FI, de même hauteur, le premier élevé à plomb <lb/>des deux côtés, & </s> <s xml:id="echoid-s715" xml:space="preserve">le ſecond avec un talud égal de chaque côté, <lb/>ce dernier quoiqu’égal au précédent en ſolidité, reſiſtera beaucoup <lb/>plus que l’autre à l’effort d’une puiſſance qui voudroit le renverſer <lb/>à droite ou à gauche, car ſupoſant que l’épaiſſeur du ſommet FG, <lb/>ne ſoit que les deux tiers de celle du ſommet AB, mais qu’en ré-<lb/>compenſe, la baſe HI, ſoit plus grande que CD, du tiers de la <lb/>même CD, les poids M, & </s> <s xml:id="echoid-s716" xml:space="preserve">N, qui exprimeront les ſuperſicies <lb/>AD, & </s> <s xml:id="echoid-s717" xml:space="preserve">FI, ſeront égaux; </s> <s xml:id="echoid-s718" xml:space="preserve">& </s> <s xml:id="echoid-s719" xml:space="preserve">comme les bras de lévier DB, & </s> <s xml:id="echoid-s720" xml:space="preserve">IL, <lb/>ſont auſſi égaux, les puiſſances P, & </s> <s xml:id="echoid-s721" xml:space="preserve">Q, ſeront donc dans la raiſon <lb/>des bras de lévier LK, & </s> <s xml:id="echoid-s722" xml:space="preserve">DE, ainſi la puiſſance P, ne ſera que <lb/>les trois quarts de la puiſſance Q, par la même raiſon ſi l’épaiſſeur <lb/>FG, n’étoit que la moitié de AB, la puiſſance P, ne ſeroit que <lb/>les deux tiers de la puiſſance Q, ce qui prouve bien la néceſſité <lb/>de donner du talud aux murs.</s> <s xml:id="echoid-s723" xml:space="preserve"/> </p> <div xml:id="echoid-div58" type="float" level="2" n="1"> <note position="left" xlink:label="note-0044-01" xlink:href="note-0044-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 12. <lb/>& 13.</note> </div> <pb o="23" file="0045" n="45" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div60" type="section" level="1" n="40"> <head xml:id="echoid-head49" xml:space="preserve">PROPOSITION TROISIEME. <lb/><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s724" xml:space="preserve">25. </s> <s xml:id="echoid-s725" xml:space="preserve">Voulant élever un Mur dont l’épaiſſeur BC, au ſom-<lb/>met ſoit donnée, auſſi-bien que ſa hauteur BA; </s> <s xml:id="echoid-s726" xml:space="preserve">on demande <lb/>quelle doit être la ligne de talud DE, pour que ce Mur étant <lb/>pouſſé de M, en B, ou tiré de C, en K, par une puiſſance, le <lb/>Mur ABCD, ſoit en équilibre avec cette puiſſance.</s> <s xml:id="echoid-s727" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s728" xml:space="preserve">Ayant nommé BC, ou AD, a; </s> <s xml:id="echoid-s729" xml:space="preserve">la hauteur CD, c; </s> <s xml:id="echoid-s730" xml:space="preserve">la ligne de <lb/> <anchor type="note" xlink:label="note-0045-01a" xlink:href="note-0045-01"/> talud DE, y; </s> <s xml:id="echoid-s731" xml:space="preserve">la ſuperficie du rectangle ABCE, ſera ac, qu’on <lb/>pourra conſiderer comme la valeur du poids H, ſuſpendu au point <lb/>F, milieu de la ligne AD, le triangle DCE, ſera {cy/2} qu’on pour-<lb/>ra auſſi conſiderer comme exprimant la valeur du poids I, ſuſ-<lb/>pendu au point G, qui eſt au deux tiers de la ligne DE; </s> <s xml:id="echoid-s732" xml:space="preserve">or ſi l’on <lb/>multiplie chacun de ces poids par leur bras de lévier, ou par <lb/>leur diſtance au point d’apui, <anchor type="note" xlink:href="" symbol="*"/> & </s> <s xml:id="echoid-s733" xml:space="preserve">qu’on ajoûte ces deux produits <anchor type="note" xlink:label="note-0045-02a" xlink:href="note-0045-02"/> enſemble, l’on aura {aac + 2acy/2} + {cyy/3} qui eſt une quantité égale <lb/>au produit de la puiſſance bf, par ſon bras de lévier EL, ce qui <lb/>donne cette équation {aac + 2acy/2} + {cyy/3} = bcf, ou bien yy + 3ay <lb/>= 3bf - {3aa/2} or pour dégager l’inconnuë y, il faut ajoûter à <lb/>chaque membre de cette équation le quarré de la moitié du coë-<lb/>ficien du ſecond terme, c’eſt-à-dire le quarré de {3a/2} qui eſt {9aa/4} & </s> <s xml:id="echoid-s734" xml:space="preserve"><lb/>pour lors l’on aura yy + 3ay + {9aa/4} = 3bf - {3aa/2} + {9aa/4} dont le <lb/>premier membre eſt un quarré parfait, ainſi extrayant la racine <lb/>quarrée de cette équation, l’on aura y + {3a/2} = √3bf - {3aa/2} + {9aa/4}\x{0020} <lb/>ou bien y = √3bf - {3aa/2} + {9aa/4}\x{0020} - {3a/2}, mais comme on peut ré-<lb/>duire {3aa/2} + {9aa/4} en leur donnant un dénominateur commun, <lb/>l’on aura + {3aa/4}, par conſequent l’équation précedente ſera <lb/> <pb o="24" file="0046" n="46" rhead="LA SCIENCE DES INGENIEURS,"/> y = √3bf + {3aa/4}\x{0020} - {3a/2} qui donne l’expreſſion la plus ſimple qu’on <lb/>puiſſe avoir de la valeur de la ligne DE.</s> <s xml:id="echoid-s735" xml:space="preserve"/> </p> <div xml:id="echoid-div60" type="float" level="2" n="1"> <note position="right" xlink:label="note-0045-01" xlink:href="note-0045-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 17.</note> <note symbol="*" position="right" xlink:label="note-0045-02" xlink:href="note-0045-02a" xml:space="preserve">Art. 23.</note> </div> </div> <div xml:id="echoid-div62" type="section" level="1" n="41"> <head xml:id="echoid-head50" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s736" xml:space="preserve">Comme je n’ai voulu obmettre aucun des principaux cas <lb/>qui peuvent ſe rencontrer dans la conſtruction des Ouvrages de <lb/>Maçonnerie, j’ai ſupoſé ici qu’il s’agiſſoit de conſtruire un Mur <lb/>dont l’épaiſſeur au ſommet devoit être déterminée pour des rai-<lb/>ſons qui obligeroient d’en uſer ainſi, & </s> <s xml:id="echoid-s737" xml:space="preserve">que ce Mur ayant à ſoû-<lb/>tenir l’effort d’une puiſſance devoit avoir neceſſairement un certain <lb/>talud pour que la longueur du lévier qui répond à la baſe étant <lb/>augmentée, ſupléât au deffaut d’epaiſſeur qu’on auroit donnée au <lb/>ſommet, parce qu’il faut s’imaginer que ſi le Mur avoit été fait à <lb/>plomb des deux côtés, l’épaiſſeur qu’on veut lui donner ne ſuffi-<lb/>roit point pour réſiſter à l’effort de la puiſſance, par conſéquent <lb/>le Probléme ſe réduit à trouver la ligne de talud DE. </s> <s xml:id="echoid-s738" xml:space="preserve">Or comme <lb/>l’équation y = √3bf + {3aa/4}\x{0020} - {3a/2} vient de nous la donner, il ne <lb/>s’agit plus que d’avoir des nombres qui expriment les lettres du ſe-<lb/>cond membre; </s> <s xml:id="echoid-s739" xml:space="preserve">c’eſt pourquoi nous ſupoſerons que la puiſſance bf, <lb/>vaut 50 pieds quarrez, & </s> <s xml:id="echoid-s740" xml:space="preserve">que a, c’eſt-à-dire la ligne AD, ou BC, <lb/>eſt de 4 pieds, ainſi comme il n’y a que ces deux grandeurs qui ſe <lb/>trouvent dans l’équation, il nous reſte à les joindre enſemble de <lb/>la façon qu’elles y ſont, c’eſt-à-dire qu’au lieu de bf, l’on aura <lb/>150, qu’au lieu de {3aa/4} l’on aura {48/4} ou bien 12 qui eſt la même <lb/>choſe, ainſi joignant 150 avec 12, l’on aura 162 dont il faut ex-<lb/>traire la racine quarrée que l’on trouvera de 12 pieds 8 pouces <lb/>9 lignes. </s> <s xml:id="echoid-s741" xml:space="preserve">Mais l’équation nous montre que de cette racine il en <lb/>faut ſouſtraire {3a/2} ou bien 12 diviſé par 2 qui eſt 6, & </s> <s xml:id="echoid-s742" xml:space="preserve">que la <lb/>difference ſera la valeur de y, retranchant donc 6 de la racine <lb/>précédente, il reſtera 6 pieds 8 pouces 9 lignes pour la ligne de <lb/>talud DE, que l’on cherche.</s> <s xml:id="echoid-s743" xml:space="preserve"/> </p> <pb o="25" file="0047" n="47" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div63" type="section" level="1" n="42"> <head xml:id="echoid-head51" xml:space="preserve">PROPOSITION QUATRIE’ME.</head> <head xml:id="echoid-head52" xml:space="preserve"> <emph style="sc">Proble’me.</emph> </head> <p style="it"> <s xml:id="echoid-s744" xml:space="preserve">26. </s> <s xml:id="echoid-s745" xml:space="preserve">Ayant le profil ABCD, d’un Mur élevé à plomb des <lb/>deux côtés, & </s> <s xml:id="echoid-s746" xml:space="preserve">dont l’épaiſſeur BC, eſt tellement proportion-<lb/> <anchor type="note" xlink:label="note-0047-01a" xlink:href="note-0047-01"/> née à la hateur CD, que ce Mur ſoit en équilibre par ſonpoids <lb/>avec la puiſſance P, qui tire de C, en E, on demande de chan-<lb/>ger ce profil-là en un autre IGHL, qui lui ſoit égalen ſuperſi-<lb/>cie, & </s> <s xml:id="echoid-s747" xml:space="preserve">en hauteur, & </s> <s xml:id="echoid-s748" xml:space="preserve">dont le côté GI, ſoit perpendiculaire, <lb/>pour que ce ſecond ſoit en équilibre par ſa réſiſtance à une <lb/>puiſſance Q, dont la force ſeroit double de la puiſſance P.</s> <s xml:id="echoid-s749" xml:space="preserve"/> </p> <div xml:id="echoid-div63" type="float" level="2" n="1"> <note position="right" xlink:label="note-0047-01" xlink:href="note-0047-01a" xml:space="preserve">Fig. 18. <lb/>& 19.</note> </div> <p> <s xml:id="echoid-s750" xml:space="preserve">Pour cela nous nommerons BC, a; </s> <s xml:id="echoid-s751" xml:space="preserve">CD, de même que GI, <lb/>c; </s> <s xml:id="echoid-s752" xml:space="preserve">GH, ou IK, x; </s> <s xml:id="echoid-s753" xml:space="preserve">KL, y; </s> <s xml:id="echoid-s754" xml:space="preserve">la puiſſance P, ſera bf, comme à <lb/>l’ordinaire, & </s> <s xml:id="echoid-s755" xml:space="preserve">la puiſſance Q, 2bf; </s> <s xml:id="echoid-s756" xml:space="preserve">cela poſé, la ſuperſicie du rec-<lb/>tangle IGHK, ou ſi l’on veut le poids N, ſera xc, & </s> <s xml:id="echoid-s757" xml:space="preserve">celle du <lb/>triangle KHL, ou le poids S, ſera {yc/2}, & </s> <s xml:id="echoid-s758" xml:space="preserve">ces deux poids étant <lb/>multipliés par leur bras de lévier<anchor type="note" xlink:href="" symbol="*"/>, réüniſſant leur produit, on <anchor type="note" xlink:label="note-0047-02a" xlink:href="note-0047-02"/> aura une quantité égale au produit de la puiſſance par ſon bras de <lb/>lévier, c’eſt-à-dire {xxc + 2yxc/2} + {yyc/3} = 2bfc, ou diviſant tous les <lb/>termes par c, l’on aura {xx+2yx/2} + {yy/3} = 2bf; </s> <s xml:id="echoid-s759" xml:space="preserve">mais comme le <lb/>rectangle BD, (ac) eſt ſupoſé égal au Trapezoïde IGHL, il vien-<lb/>dra encore cette équation ac = cx + {cy/2}, d’où dégageant l’in-<lb/>connuë y, l’on aura y = 2a - 2x, & </s> <s xml:id="echoid-s760" xml:space="preserve">ſubſtituant la valeur de y, <lb/>dans l’équation {xx + 2xy/2} + {yy/3} = 2bf, cela donne {xx/2} + 2ax <lb/>- 2xx + {4aa - 8ax + 4xx/3} = 2bf, qui, étant réduite, donne <lb/>4aa - 2ax - {xx/2} = 6bf, ou bien {xx/2} + 2ax = 4aa - 6bf, & </s> <s xml:id="echoid-s761" xml:space="preserve">faiſant <lb/>évanoüir la fraction l’on a xx + 4ax = 8aa - 12bf, à quoiajoûtant <lb/>4aa de part & </s> <s xml:id="echoid-s762" xml:space="preserve">d’autre pour rendre le premier membre un quarré <lb/>parfait, il viendra xx + 4ax + 4aa = 12aa - 12bf, d’où l’on tire <lb/>x = √12aa - 12bf\x{0020} - 2a, après avoir extrait la racine quarrée.</s> <s xml:id="echoid-s763" xml:space="preserve"/> </p> <div xml:id="echoid-div64" type="float" level="2" n="2"> <note symbol="*" position="right" xlink:label="note-0047-02" xlink:href="note-0047-02a" xml:space="preserve">Art. 23.</note> </div> <pb o="26" file="0048" n="48" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div66" type="section" level="1" n="43"> <head xml:id="echoid-head53" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s764" xml:space="preserve">L’on ſait que la puiſſance P, étant en équilibre avec le poids <lb/>O, l’on a<anchor type="note" xlink:href="" symbol="*"/> a = √2bf\x{0020}, ainſi ſupoſant bf=72, il vient 12 = √2bf,\x{0020} par <anchor type="note" xlink:label="note-0048-01a" xlink:href="note-0048-01"/> conſéquent l’épaiſſeur BC, ſera de 12 pieds, quant à la hauteur <lb/>CD, nous la ſupoſerons de 30, quoiqu’on puiſſe s’en paſſer ici; <lb/></s> <s xml:id="echoid-s765" xml:space="preserve">préſentement pour connoître la valeur de x, j’entend l’épaiſſeur <lb/>GH, il ne faut que ſuivre ce qui eſt indiqué dans l’équation der-<lb/>niere, c’eſt-à-dire, ôter de 12aa, qui valent 1728, 12bf, qui eſt <lb/>864 & </s> <s xml:id="echoid-s766" xml:space="preserve">extraire la racine quarrée de la difference pour avoir 29 <lb/>pieds 4 pouces 8 lignes, d’où ſouſtrayant la valeur de 2a, qui eſt <lb/>24 pieds, l’on aura 5 pieds 4 pouces 8 lignes pour la valeur de x, <lb/>ou l’épaiſſeur GH, par le moyen de laquelle il ſera facile d’avoir <lb/>la ligne KL, ou y, que l’on trouvera de 13 pieds 2 pouces 8 li-<lb/>gnes, à quoi ajoûtant la valeur de x, il viendra 18 pieds 7 pouces <lb/>4 lignes pour la baſe IL, du Mur: </s> <s xml:id="echoid-s767" xml:space="preserve">or comme le rectangle AC, <lb/>ayant 12 pieds de baſe ſur 30 de hauteur vaut 360 pieds de ſuper-<lb/>ficie, & </s> <s xml:id="echoid-s768" xml:space="preserve">que celle du Trapezoïde IGHL, en vaut autant (comme <lb/>il eſt aiſé de s’en convaincre ſi l’on en fait le calcul) il s’enſuit <lb/>donc qu’on a ſatisfait exactement aux conditions du Problême.</s> <s xml:id="echoid-s769" xml:space="preserve"/> </p> <div xml:id="echoid-div66" type="float" level="2" n="1"> <note symbol="*" position="left" xlink:label="note-0048-01" xlink:href="note-0048-01a" xml:space="preserve">Art.</note> </div> </div> <div xml:id="echoid-div68" type="section" level="1" n="44"> <head xml:id="echoid-head54" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s770" xml:space="preserve">27. </s> <s xml:id="echoid-s771" xml:space="preserve">L’on pourroit encore rendre le ſecond profil capable de <lb/>ſoûtenir l’effort d’une puiſſance plus grande que 2bf, car moins le <lb/>ſommet du revêtement aura d’épaiſſeur, & </s> <s xml:id="echoid-s772" xml:space="preserve">plus la ligne de talud <lb/>augmentera la longueur du bras de lévier ML, par conſéquent <lb/>la réſiſtance du Mur, & </s> <s xml:id="echoid-s773" xml:space="preserve">cette augmentation pourra toûjours aller <lb/>en croiſſant tant que le point H, ſoit confondu avec le point G, <lb/>c’eſt-à-dire que la ligne GH, ſoit réduite à zero; </s> <s xml:id="echoid-s774" xml:space="preserve">parce qu’alors le <lb/>profil deviendra un triangle rectangle, qui eſt la figure capable de <lb/>ſoûtenir la plus grande puiſſance qu’il eſt poſſible, comme on l’a <lb/>vû dans l’article 20<emph style="sub">e</emph>, & </s> <s xml:id="echoid-s775" xml:space="preserve">je trouve ici que ſi le premier profil étoit <lb/>changé en triangle, au lieu de ſoutenir en équilibre une puiſſan-<lb/>ce de 72 pieds, il en ſoutiendroit une de 145 {1/3}.</s> <s xml:id="echoid-s776" xml:space="preserve"/> </p> <pb file="0049" n="49"/> <pb file="0049a" n="50"/> <figure> <image file="0049a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0049a-01"/> </figure> <pb file="0050" n="51"/> <pb o="27" file="0051" n="52" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div69" type="section" level="1" n="45"> <head xml:id="echoid-head55" xml:space="preserve">PROPOSITION CINQUIE’ME.</head> <head xml:id="echoid-head56" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s777" xml:space="preserve">28. </s> <s xml:id="echoid-s778" xml:space="preserve">Ayant comme dans le Probléme précédent un profil <lb/> <anchor type="note" xlink:label="note-0051-01a" xlink:href="note-0051-01"/> rectangulaire AC, en équilibre par ſon poids avec une puiſ-<lb/>ſance P, on demande un autre profil GHIK, qui ait la mê-<lb/>me hauteur, que le précédent, mais dont la ſuperficie n’en <lb/>ſoit que les trois quarts, avec cette condition que le Mur GHIK, <lb/>ſoit encore en équilibre par ſa réſiſtance à l’effort de la puiſ-<lb/>ſance P, qu’on ſupoſe agir toûjours avec la même force.</s> <s xml:id="echoid-s779" xml:space="preserve"/> </p> <div xml:id="echoid-div69" type="float" level="2" n="1"> <note position="right" xlink:label="note-0051-01" xlink:href="note-0051-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 18. <lb/>& 20.</note> </div> <p> <s xml:id="echoid-s780" xml:space="preserve">Nommant les lignes BA, ou HG, c; </s> <s xml:id="echoid-s781" xml:space="preserve">AD, a; </s> <s xml:id="echoid-s782" xml:space="preserve">HI, ou GL, <lb/>x; </s> <s xml:id="echoid-s783" xml:space="preserve">LK, y; </s> <s xml:id="echoid-s784" xml:space="preserve">l’on aura ac, pour le rectangle BD, cx, pour le rectan-<lb/>gle HL, ou ſi l’on veut pour le poids Q, & </s> <s xml:id="echoid-s785" xml:space="preserve">{cy/2} pour le trian-<lb/>gle ILK, qui eſt la même choſe que le poids P; </s> <s xml:id="echoid-s786" xml:space="preserve">or comme le <lb/>Trapeze GHIK, ne doit être que les trois quarts du rectangle <lb/>BD, l’on aura donc {3ac/4} = cx + {cy/2}, & </s> <s xml:id="echoid-s787" xml:space="preserve">ſi l’on réünit le poids Q, <lb/>avec le poids P, après les avoir multipliés par leur bras de léviers, <lb/>l’on aura une quantité égale au produit de la puiſſance P, qui eſt <lb/>toûjours bf, par le bras de lévier KR, ce qui donne cette ſeconde <lb/>équation {xxc/2} + xyc + {yyc/3} = bcf, ou en effaçant de tous les termes <lb/>la lettre c, {xx/2} + xy + {yy/3} = bf, mais ſi dans la premiere équation <lb/>{3ac/4} = cx + {yc/2} l’on dégage y, l’on aura {ba/4} - 2x = y, & </s> <s xml:id="echoid-s788" xml:space="preserve">ſupo-<lb/>ſant {6a/4} = n, pour plus de facilité, l’on aura n - 2x = y. </s> <s xml:id="echoid-s789" xml:space="preserve">Si pre-<lb/>ſentement l’on ſubſtituë la valeur de y, dans l’équation {xx/2} + yx <lb/>+ {yy/3} = bf, elle ſera changée en celle-cy{xx/2} + nx - 2xx <lb/>+ {nn - 4nx + 4xx/3} = bf, d’où faiſant évanoüir la fraction l’on a <lb/>3xx + 6nx - 12xx + 2nn - 8nx + 8xx = 6fb, qui étant réduite <lb/>donne 2nn - xx - 2nx = 6bf, ou bien 2nn - 6bf = xx + 2nx; </s> <s xml:id="echoid-s790" xml:space="preserve">or <pb o="28" file="0052" n="53" rhead="LA SCIENCE DES INGENIEURS,"/> ſi à cette équation l’on ajoûte nn de part & </s> <s xml:id="echoid-s791" xml:space="preserve">d’autre, l’on aura 3nn <lb/>- 6bf = xx + 2nx + nn, dont extrayant la racine quarrée & </s> <s xml:id="echoid-s792" xml:space="preserve">déga-<lb/>geant l’inconnuë, il vient enfin √3nn - 6bf\x{0020} - n = x, qui donne <lb/>la valeur de l’épaiſſeur HI.</s> <s xml:id="echoid-s793" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s794" xml:space="preserve">Pour avoir l’autre inconnuë y, nous ſupoſerons √3nn - 6bf\x{0020} <lb/>- n = d, pour lors l’on aura 2d = 2x, & </s> <s xml:id="echoid-s795" xml:space="preserve">mettant la valeur de 2x, <lb/>dans l’équation, n - 2x = y, l’on aura n - 2d = y.</s> <s xml:id="echoid-s796" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div71" type="section" level="1" n="46"> <head xml:id="echoid-head57" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s797" xml:space="preserve">Comme nous avons ſupoſé {6a/4} = n, & </s> <s xml:id="echoid-s798" xml:space="preserve">que a, vaut 12 pieds <lb/> <anchor type="note" xlink:label="note-0052-01a" xlink:href="note-0052-01"/> de même que dans le Probléme précédent, n, ſera donc de 18, <lb/>par conſequent 3nn, vaudront 972 pieds. </s> <s xml:id="echoid-s799" xml:space="preserve">Or comme bf, vaut en-<lb/>core 72, ſi l’on ſouſtrait 6bf, c’eſt-à-dire ſa valeur qui eſt 432 <lb/>du nombre précédent, l’on aura 405 pour la difference, dont <lb/>extrayant la racine quarrée, on la trouvera de 23 pieds 3 pouces, <lb/>de laquelle ôtant la valeur de n, qui eſt 18, l’on verra que l’é-<lb/>paiſſeur HI, doit être de 5 pieds 3 pouces, & </s> <s xml:id="echoid-s800" xml:space="preserve">que par conſéquent <lb/>la ligne de talud LK, c’eſt-à-dire, y, vaut 7 pieds 6 pouces, à <lb/>laquelle ajoutant GL, je veux dire, 5 pieds 3 pouces, l’on aura <lb/>12 pieds 9 pouces pour toute la baſe GK; </s> <s xml:id="echoid-s801" xml:space="preserve">ce qui eſt bien évident <lb/>puiſqu’un Trapezoïde qui auroit 30 pieds de hauteur, & </s> <s xml:id="echoid-s802" xml:space="preserve">pour <lb/>côtés paralelles une ligne de 5 pieds 3 pouces & </s> <s xml:id="echoid-s803" xml:space="preserve">une autre de 12 <lb/>pieds 9 pouces, vaudra 270 pieds de ſuperficie qui eſt juſtement <lb/>les trois quarts du rectangle BD, qui en doit valoir 360.</s> <s xml:id="echoid-s804" xml:space="preserve"/> </p> <div xml:id="echoid-div71" type="float" level="2" n="1"> <note position="left" xlink:label="note-0052-01" xlink:href="note-0052-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 18. <lb/>& 20.</note> </div> </div> <div xml:id="echoid-div73" type="section" level="1" n="47"> <head xml:id="echoid-head58" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s805" xml:space="preserve">29. </s> <s xml:id="echoid-s806" xml:space="preserve">L’on pourroit, ſi l’on vouloit, diminuer encore la Maçon-<lb/>nerie du Probléme précédent, en ne ſupoſant la ſuperficie du ſe-<lb/>cond proſil, que des deux tiers de celle du premier, & </s> <s xml:id="echoid-s807" xml:space="preserve">pour lors <lb/>l’on trouvera que x, ou ſi l’on veut, le ſommet du Mur, ne doit <lb/>avoir que 2 pieds d’épaiſſeur; </s> <s xml:id="echoid-s808" xml:space="preserve">mais comme il y a des cas où cette <lb/>épaiſſeur ne ſuffiroit pas pour des murs qui ont à ſoûtenir certaine <lb/>pouſſée, on ſera le maître de ne diminuer le Mur que d’un quart <lb/>ou d’un cinquiéme, plus ou moins, ſelon les occaſions; </s> <s xml:id="echoid-s809" xml:space="preserve">tout ce que <lb/>l’on doit remarquer, c’eſt que ſi la diminution qu’on voudroit <lb/>faire étoit trop grande, on s’en apercevroit en donnant aux termes <lb/>du premier membre de l’équation √3nn - 6bf\x{0020} - n = x, la valeur <lb/>en nombre des lettres qui le compoſent, car ſi l’on trouve, par <pb o="29" file="0053" n="54" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> exemple, que 3nn, ſoient moindres que 6bf, c’eſt une marque que <lb/>ce Probléme eſt impoſſible; </s> <s xml:id="echoid-s810" xml:space="preserve">que ſi l’on trouve √3nn - 6bf\x{0020} = n, <lb/>c’eſt un ſigne que x, eſt égal à zero, c’eſt-à-dire que le ſommet <lb/>du Mur ſera la pointe d’un triangle dont l’épaiſſeur ſera zero.</s> <s xml:id="echoid-s811" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div74" type="section" level="1" n="48"> <head xml:id="echoid-head59" xml:space="preserve">CHAPITRE QUATRIE’ME.</head> <p style="it"> <s xml:id="echoid-s812" xml:space="preserve">De la maniere de calculer la pouſſée des Terres que ſoû-<lb/>tiennent le revêtemens des Terraſſes & </s> <s xml:id="echoid-s813" xml:space="preserve">des Rempars, <lb/>afin de ſavoir l’épaiſſeur qu’il faut leur donner.</s> <s xml:id="echoid-s814" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div75" type="section" level="1" n="49"> <head xml:id="echoid-head60" xml:space="preserve">PRINCIPE TIRE’ DE LA ME’CANIQUE.</head> <p> <s xml:id="echoid-s815" xml:space="preserve">30. </s> <s xml:id="echoid-s816" xml:space="preserve">SI l’on a un poids H, ſur un plan incliné AC, & </s> <s xml:id="echoid-s817" xml:space="preserve">une puiſ-<lb/> <anchor type="note" xlink:label="note-0053-01a" xlink:href="note-0053-01"/> ſance K, qui ſoûtienne ce poids ſelon une direction EK, <lb/> <anchor type="note" xlink:label="note-0053-02a" xlink:href="note-0053-02"/> paralelle à l’horiſon, il eſt démontré dans la Mécanique que la <lb/>puiſſance K, eſt au poids comme la hauteur AB, du plan incliné <lb/>eſt à la longueur BC, de la baſe, or ſi l’on ſupoſe que la hauteur <lb/>AB, ſoit égale à la baſe BC, c’eſt-à-dire que la ligne AC, ſoit la <lb/>diagonale d’un quarré, la puiſſanceſera égale au poids, mais comme <lb/>c’eſt la même choſe que la puiſſance tire de E, en K, ou ſoit <lb/>apliquée au poids même, comme eſt la puiſſance P, qui pouſſe <lb/>par une direction diamêtrale EG, paralelle à l’horiſon, on peut <lb/>donc dire que la puiſſance P, a beſoin d’une force égale au poids <lb/>pour le ſoûtenir en équilibre.</s> <s xml:id="echoid-s818" xml:space="preserve"/> </p> <div xml:id="echoid-div75" type="float" level="2" n="1"> <note position="right" xlink:label="note-0053-01" xlink:href="note-0053-01a" xml:space="preserve"><emph style="sc">Planch.</emph> <lb/>2.</note> <note position="right" xlink:label="note-0053-02" xlink:href="note-0053-02a" xml:space="preserve"><emph style="sc">Fig. i</emph>. <lb/>V. le C. <lb/>art. 781. <lb/>& 786.</note> </div> </div> <div xml:id="echoid-div77" type="section" level="1" n="50"> <head xml:id="echoid-head61" xml:space="preserve">Principe d’Experience.</head> <p> <s xml:id="echoid-s819" xml:space="preserve">31. </s> <s xml:id="echoid-s820" xml:space="preserve">C’eſt une choſe démontrée par l’experience, que les Terres <lb/>ordinaires, quand elles ſont nouvellement remuées & </s> <s xml:id="echoid-s821" xml:space="preserve">miſes les <lb/>unes ſur les autres ſans être battuës ni entre-laſſées par aucun faſ-<lb/>cinage, prennent d’elles-mêmes une pente ou talud, qui fait avec <lb/>l’horiſon un angle de 45 degrés, ou qui ſuit la diagonale d’un <lb/>quarré je dis que cela arrive aux Terres ordinaires; </s> <s xml:id="echoid-s822" xml:space="preserve">car nous <lb/>n’ignorons pas que ſi elles étoient ſablonneuſes, elles ne faſſent <lb/>un angle plus aigu, & </s> <s xml:id="echoid-s823" xml:space="preserve">qu’au contraire ſi elles étoient graſſes & </s> <s xml:id="echoid-s824" xml:space="preserve"><lb/>fortes elles n’en faſſent un plus ouvert, mais pour tabler ſur quel-<lb/>que choſe de fixe, nous avons ſupoſé une terre qui tiendroit un <lb/>milieu entre ces deux-ci.</s> <s xml:id="echoid-s825" xml:space="preserve"/> </p> <pb o="30" file="0054" n="55" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s826" xml:space="preserve">Prévenus de cela, imaginons que contre une Muraille A, on <lb/> <anchor type="note" xlink:label="note-0054-01a" xlink:href="note-0054-01"/> ait ramaſſé des Terres ſoutenuës de l’autre côté par une furface <lb/>DE, qu’une puiſſance Q, qui la maintient peut ôter librement; <lb/></s> <s xml:id="echoid-s827" xml:space="preserve">ces Terres étant renfermées dans l’eſpace BCDE, comme dans une <lb/>caiſſe, dont le profil CD, ſeroit un quarré, il eſt conſtant que ſi <lb/>l’on ôtoit la ſurface DE, pour laiſſer aux Terres la liberté d’agir, <lb/>qu’il s’en ébouleroit une partie, & </s> <s xml:id="echoid-s828" xml:space="preserve">qu’il ne reſteroit que celles du <lb/>triangle CBE, & </s> <s xml:id="echoid-s829" xml:space="preserve">que par conſéquent la puiſſance Q, ſoûtient toute <lb/>la pouſſée des Terres dutriangle BDE, je veux dire l’effort qu’elles <lb/>font pour rouler le long du Plan incliné BE, il s’enſuit donc que la <lb/>puiſſance Q, auroit beſoin d’une force exprimée par le triangle <lb/>BDE, ſi effectivement les Terres s’ébouloient avec autant de faci-<lb/>lité qu’un corps Spherique roule ſur un Plan incliné bien poli, <lb/>mais comme leur tenacité fait que leurs parties ne peuvent ſe dé-<lb/>tacher pour s’ébouler, ſans rencontrer beaucoup d’obſtacles, il eſt <lb/>certain, comme l’experience le fait voir, qu’elles ne font pas ſeu-<lb/>lement la moitié de l’effort contre la ſurface DE, qu’elles feroient <lb/>ſi elles étoient ramaſſées dans un corps Spherique, ainſi on peut <lb/>donc conſiderer la puiſſance Q, comme équivalente à un Plan qui <lb/>ſeroit exprimé par la moitié du triangle BDE, pour être en équi-<lb/>libre avec la pouſſée des Terres, ce qui convient d’autant mieux <lb/>avec la pratique qu’on ne les employe jamais pour élever des <lb/>Rempars, des Terraſſes, des Chauſſées, &</s> <s xml:id="echoid-s830" xml:space="preserve">c. </s> <s xml:id="echoid-s831" xml:space="preserve">qu’elles ne ſoient <lb/>bien battuës, & </s> <s xml:id="echoid-s832" xml:space="preserve">qu’on n’en ait pour ainſi dire augmenté la tenacité.</s> <s xml:id="echoid-s833" xml:space="preserve"/> </p> <div xml:id="echoid-div77" type="float" level="2" n="1"> <note position="left" xlink:label="note-0054-01" xlink:href="note-0054-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 2.</note> </div> <p> <s xml:id="echoid-s834" xml:space="preserve">Comme c’eſt ſur ce principe que nous agirons dans la ſuite, on <lb/>remarquera que ſi l’on ſupoſe les lignes BD, & </s> <s xml:id="echoid-s835" xml:space="preserve">DE, chacune de <lb/>deux pieds, la ſuperficie du triangle ſera de deux pieds quarrés, & </s> <s xml:id="echoid-s836" xml:space="preserve"><lb/>la puiſſance Q, n’en ſoutenant que la moitié, on peut dire que <lb/>la force de cette puiſſance dans l’état d’équilibre, ſera exprimée par <lb/>un pied quarré.</s> <s xml:id="echoid-s837" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div79" type="section" level="1" n="51"> <head xml:id="echoid-head62" xml:space="preserve">PROPOSITION PREMIERE.</head> <head xml:id="echoid-head63" xml:space="preserve"> <emph style="sc">Proble’me</emph> </head> <p style="it"> <s xml:id="echoid-s838" xml:space="preserve">32. </s> <s xml:id="echoid-s839" xml:space="preserve">Qui enſeigne comme il faut calculer la pouſſée des <lb/>Terres pour proportionner l’épaiſſeur des Murs qui les doi-<lb/>vent ſoûtenir en équilibre.</s> <s xml:id="echoid-s840" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s841" xml:space="preserve">Pour ſavoir quel effort font les Terres derriere le revêtement <lb/> <anchor type="note" xlink:label="note-0054-02a" xlink:href="note-0054-02"/> BCDE, je prend la ligne AB, égale à BD, pour avoir le triangle <pb o="31" file="0055" n="56" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE"/> rectangle & </s> <s xml:id="echoid-s842" xml:space="preserve">iſocelle ABD, qui comprend toutes les Terres qui <lb/>pouſſent, puiſque par l’Article 31. </s> <s xml:id="echoid-s843" xml:space="preserve">celles qui ſont ſous la ligne <lb/>AD, ſe ſoutiennent par elles-mêmes, l’angle ADX, étant de 45 <lb/>degrés; </s> <s xml:id="echoid-s844" xml:space="preserve">mais comme ces Terres agiſſant avec plus ou moins de <lb/>force ſelon qu’elles ſont plus ou moins éloignées du ſommet B, <lb/>il faut faire enſorte de raporter toute la pouſſée au point B; </s> <s xml:id="echoid-s845" xml:space="preserve">pour <lb/>cela je diviſe la hauteur BD, en un grand nombre de parties égales, <lb/>par exemple, en autant de parties qu’elle contient de pieds, ainſi <lb/>ſupoſant qu’il ſoit queſtion d’un revêtement de 15 pieds de hau-<lb/>teur, on aura 15 parties égales, & </s> <s xml:id="echoid-s846" xml:space="preserve">ſi par chaque point de diviſion <lb/>l’on mene à la ligne DA, les paralelles HG, NM, PO, RQ, &</s> <s xml:id="echoid-s847" xml:space="preserve">c. <lb/></s> <s xml:id="echoid-s848" xml:space="preserve">l’on aura d’abord un petit tiangle HGB, enſuite une quantité de <lb/>Trapezes qui vont toûjours en augmentant, & </s> <s xml:id="echoid-s849" xml:space="preserve">qu’on doit conſide-<lb/>rer comme autant de puiſſances qui pouſſent le mur; </s> <s xml:id="echoid-s850" xml:space="preserve">or pour ſa-<lb/>voir la pouſſée de chacun, commençons par le triangle HGB, <lb/>qu’on peut regarder ſelon l’Article 31. </s> <s xml:id="echoid-s851" xml:space="preserve">comme un corps poſé ſur <lb/>le Plan incliné LGH, qui agit contre la ſurface BH, pour la <lb/>renverſer, ſi l’on nomme b, l’effort que fait le triangle contre la <lb/>ſurface, on pourra, connoiſſant la pouſſée du triangle, connoître <lb/>auſſi celle de tous les Trapezes qui ſont immédiatement après, car <lb/>comme la Trapeze GN, eſt triple du triangle HGB, ſon effort contre <lb/>la ſurface HN, ſera 3 b, & </s> <s xml:id="echoid-s852" xml:space="preserve">la pouſſée de tous les autres Trapezes <lb/>ſuivans pourra être exprimée par les differences des quarrés des ter-<lb/>mes d’une progreſſion Arithmétique, ce qui donne cette progreſſion <lb/>b. </s> <s xml:id="echoid-s853" xml:space="preserve">3 b. </s> <s xml:id="echoid-s854" xml:space="preserve">5 b. </s> <s xml:id="echoid-s855" xml:space="preserve">7 b. </s> <s xml:id="echoid-s856" xml:space="preserve">9 b. </s> <s xml:id="echoid-s857" xml:space="preserve">11 b. </s> <s xml:id="echoid-s858" xml:space="preserve">13 b. </s> <s xml:id="echoid-s859" xml:space="preserve">15 b. </s> <s xml:id="echoid-s860" xml:space="preserve">17 b. </s> <s xml:id="echoid-s861" xml:space="preserve">19 b. </s> <s xml:id="echoid-s862" xml:space="preserve">21 b. </s> <s xml:id="echoid-s863" xml:space="preserve">23 b. </s> <s xml:id="echoid-s864" xml:space="preserve">25 b. </s> <s xml:id="echoid-s865" xml:space="preserve">27 b. </s> <s xml:id="echoid-s866" xml:space="preserve">29 b. </s> <s xml:id="echoid-s867" xml:space="preserve"><lb/>Or ſi l’on ſupoſe que l’action du triangle HGB, au lieu d’agir le long <lb/>de la ſurface BH, ſoit réünie au point B, que l’action du Trapeze <lb/>GN, ſoit réünie au point H, & </s> <s xml:id="echoid-s868" xml:space="preserve">qu’il en ſoit de même pour l’action <lb/>de tousles autres Trapezes réünie aux points N, P, R, & </s> <s xml:id="echoid-s869" xml:space="preserve">on pour-<lb/>ra concevoir qu’une puiſſance exprimée par b, agit à l’extrémité B, <lb/>du bras delévier BD, qu’une autre exprimée par 3.</s> <s xml:id="echoid-s870" xml:space="preserve">b, agit à l’extrê-<lb/>mité H, du bras de levier DH, & </s> <s xml:id="echoid-s871" xml:space="preserve">qu’en étant de même pour <lb/>tous les autres Trapezes ou puiſſances, il y aura autant de léviers <lb/>que de puiſſances, & </s> <s xml:id="echoid-s872" xml:space="preserve">cesléviers ſeront dans une progreſſion Arith-<lb/>métique des nombres naturels, dont le premier terme ſera le lévier <lb/>BD, & </s> <s xml:id="echoid-s873" xml:space="preserve">le plus petit le lévier DK, de ſorte que la progreſſion des <lb/>léviers ira en diminuant tandis que celle des puiſſances ira en aug-<lb/>mentant; </s> <s xml:id="echoid-s874" xml:space="preserve">car ſi l’on range ces deux progreſſions l’une ſur l’autre de <lb/>maniere que chaque puiſſance réponde à ſon lévier, l’on aura <lb/>b. </s> <s xml:id="echoid-s875" xml:space="preserve">3 b. </s> <s xml:id="echoid-s876" xml:space="preserve">5 b. </s> <s xml:id="echoid-s877" xml:space="preserve">7 b. </s> <s xml:id="echoid-s878" xml:space="preserve">9 b. </s> <s xml:id="echoid-s879" xml:space="preserve">11 b. </s> <s xml:id="echoid-s880" xml:space="preserve">13 b. </s> <s xml:id="echoid-s881" xml:space="preserve">15 b. </s> <s xml:id="echoid-s882" xml:space="preserve">17 b. </s> <s xml:id="echoid-s883" xml:space="preserve">19 b. </s> <s xml:id="echoid-s884" xml:space="preserve">21 b. </s> <s xml:id="echoid-s885" xml:space="preserve">23 b. </s> <s xml:id="echoid-s886" xml:space="preserve">25 b. </s> <s xml:id="echoid-s887" xml:space="preserve">27 b. </s> <s xml:id="echoid-s888" xml:space="preserve">29. </s> <s xml:id="echoid-s889" xml:space="preserve">b. </s> <s xml:id="echoid-s890" xml:space="preserve"><lb/>15. </s> <s xml:id="echoid-s891" xml:space="preserve">14. </s> <s xml:id="echoid-s892" xml:space="preserve">13. </s> <s xml:id="echoid-s893" xml:space="preserve">12. </s> <s xml:id="echoid-s894" xml:space="preserve">11. </s> <s xml:id="echoid-s895" xml:space="preserve">10. </s> <s xml:id="echoid-s896" xml:space="preserve">9. </s> <s xml:id="echoid-s897" xml:space="preserve">8. </s> <s xml:id="echoid-s898" xml:space="preserve">7. </s> <s xml:id="echoid-s899" xml:space="preserve">6. </s> <s xml:id="echoid-s900" xml:space="preserve">5. </s> <s xml:id="echoid-s901" xml:space="preserve">4. </s> <s xml:id="echoid-s902" xml:space="preserve">3. </s> <s xml:id="echoid-s903" xml:space="preserve">2. </s> <s xml:id="echoid-s904" xml:space="preserve">1.</s> <s xml:id="echoid-s905" xml:space="preserve"/> </p> <div xml:id="echoid-div79" type="float" level="2" n="1"> <note position="left" xlink:label="note-0054-02" xlink:href="note-0054-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <pb o="32" file="0056" n="57" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s906" xml:space="preserve">Mais l’on ſait que les effets de pluſieurs puiſſances apliquées à <lb/>des léviers, ſont dans la raiſon compoſée de leur force & </s> <s xml:id="echoid-s907" xml:space="preserve">de la lon-<lb/>gueur de leur léviers; </s> <s xml:id="echoid-s908" xml:space="preserve">c’eſt pourquoi, afin d’avoir l’effort dont cha-<lb/>que puiſſance eſt capable, il faudra la multiplier par ſon bras de <lb/>lévier, & </s> <s xml:id="echoid-s909" xml:space="preserve">la ſomme de tous les produits ſera égale à l’effort to-<lb/>tal de toutes les puiſſances apliquées à leur bras de léviers; </s> <s xml:id="echoid-s910" xml:space="preserve">mais <lb/>comme chaque puiſſance pourra être tranſportée à l’extrêmité B, <lb/>du bras DB, (en diviſant ſelon l’Article 11. </s> <s xml:id="echoid-s911" xml:space="preserve">le produit de ſa force <lb/>& </s> <s xml:id="echoid-s912" xml:space="preserve">de ſon levier par toute la longueur BB,) on n’aura donc qu’à <lb/>diviſer les produits dont nous venons de parler, par le diviſeur <lb/>commun {1240b/15} = 826 {2/3} de ſorte que ſi l’on ſu-<lb/>poſe 82 {2/3} = f, l’on aura bf, pour l’effort de toutes les puiſſances <lb/>réünies au point B.</s> <s xml:id="echoid-s913" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s914" xml:space="preserve">Voulant ſavoir préſentement ce que bf, vaut en pieds quarrés, <lb/>il faut ſe rapeller que b, a été ſupoſé égal à la pouſſée du trian-<lb/>gle HGB, contre la ſurface BH. </s> <s xml:id="echoid-s915" xml:space="preserve">Or comme les côtés BG, & </s> <s xml:id="echoid-s916" xml:space="preserve">BH, <lb/>de ce triangle ſont chacun d’un pied, ſa ſuperficie ſera de 6 pou-<lb/>ces & </s> <s xml:id="echoid-s917" xml:space="preserve">la ſurface BH, n’en ſoutenant que la moitié par l’Article <lb/>31, à cauſe de la tenacité des Terres; </s> <s xml:id="echoid-s918" xml:space="preserve">b, ſera donc de 3 pouces <lb/>de pieds quarrés, ainſi multipliant 3 pouces par 82 pieds 8 pou-<lb/>ces, le produit ſera 20 pieds 8 pouces pour la valeur de bf.</s> <s xml:id="echoid-s919" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s920" xml:space="preserve">Il eſt bon que je m’arrête ici un moment, afin d’expliquer pour-<lb/>quoi la tenacité des terres diminuë leur pouſſée de la moitié de <lb/>l’effort qu’elles feroient derriere le revêtement, ſi, au lieu d’agir <lb/>comme elles font, elles agiſſoient comme un corps Spherique qui <lb/>ſeroit ſur le Plan incliné AD, ou comme un coin ABD, dont tou-<lb/>tes les parties ſeroient parfaitement unies.</s> <s xml:id="echoid-s921" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s922" xml:space="preserve">Remarquez que le triangle GBH, s’apuyant ſur le Trapeze <lb/>MGHN, les terres de ce Trapeze ſont plus preſſées que celles <lb/>du triangle, de même les Terres du Trapeze OMNP, ſont auſſi <lb/>plus preſſées que celles qui ſont dans celui de deſſus, les Terres <lb/>du Trapeze QOPR, plus preſſées encore que celles du précédent, <lb/>ainſi des autres Trapezes, qui ſeront toûjours plus preſſées, à me-<lb/>ſure qu’ils approcheront du Plan incliné AD: </s> <s xml:id="echoid-s923" xml:space="preserve">& </s> <s xml:id="echoid-s924" xml:space="preserve">comme tous ces <lb/>Trapezes depuis le plus petit juſqu’au plus grand ſe ſurpaſſent éga-<lb/>lement, on peut donc dire que leur preſſion ou leur tenacité aug-<lb/>mente dans la raiſon des termes d’une progreſſion Arithmétique, <lb/>& </s> <s xml:id="echoid-s925" xml:space="preserve">que latenacité qui eſtrépanduë dans tout le triangle ABD, n’eſt <lb/>que la moitié de ce qu’elle ſeroit, ſi ſe trouvant uniforme dans <pb o="33" file="0057" n="58" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> chaque Trapeze, elle étoit égale à celle du dernier. </s> <s xml:id="echoid-s926" xml:space="preserve">Or comme <lb/>la pouſſée des Trapezes derriere le revêtement CD, doit diminuer <lb/>dans la même raiſon que leur tenacité augmente, il m’a parû que <lb/>pour y avoir égard, il faloit ne prendre que la moitié de la ſuper-<lb/>ficie du petit triangle GBH, pour la valeur de la puiſſance b, ce <lb/>que j’ai fait avec d’autant plus d’aſſurance, que je me ſuis aperçû <lb/>que tous les calculs que j’ai faits pour trouver l’épaiſſeur des revê-<lb/>temens ſe rencontroient parfaitement bien avec ce que l’experience <lb/>a pû autoriſer: </s> <s xml:id="echoid-s927" xml:space="preserve">ainſi je finis cette Digreſſion, pour reprendre la ſuite <lb/>de l’Article précédent.</s> <s xml:id="echoid-s928" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s929" xml:space="preserve">Mais comme les pieds quarrés que nous venons de trouver ne <lb/>ſont point homogenes, avec ceux qui doivent exprimer la valeur <lb/>du poids r, les uns provenans du triangle de Terre ABD, & </s> <s xml:id="echoid-s930" xml:space="preserve">les <lb/>autres du profil de Maçonnerie CD, il faut donc en ſuivant ce <lb/>qui a été dit dans l’Article 5. </s> <s xml:id="echoid-s931" xml:space="preserve">faire une reduction dans les premiers, <lb/>c’eſt-à-dire prendre les deux tiers de 20 pieds 8 pouces, parce qu’un <lb/>pied cube de Terre péſe moins d’un tiers qu’un pied cube de Ma-<lb/>çonnerie, & </s> <s xml:id="echoid-s932" xml:space="preserve">pour lors bf, ou la puiſſance ne vaudra que 13 pieds <lb/>9 pouces 4 lignes.</s> <s xml:id="echoid-s933" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s934" xml:space="preserve">Preſentement que l’on eſt prévenu de la valeur de la puiſſance <lb/>il ne s’agit plus que de chercher, comme on l’a fait dans le Cha-<lb/>pitre précédent, quelle épaiſſeur il faut donner au ſommet BC, & </s> <s xml:id="echoid-s935" xml:space="preserve"><lb/>à la baſe DF, du revétement, pour qu’elle ſoit en équilibre par ſon <lb/>poids avec cette puiſſance, ou ſi l’on veut avec la pouſſée des Ter-<lb/>res; </s> <s xml:id="echoid-s936" xml:space="preserve">pour cela nous ſupoſerons que la puiſſance, au lieu de pouſſer <lb/>de M, en B, tire de B, en T, ce qui eſt la même choſe, & </s> <s xml:id="echoid-s937" xml:space="preserve"><lb/>menant du point d’apui F, la perpendiculaire FS, ſur la direction <lb/>BT, on prendra cette perpendiculaire à la place du bras de lévier <lb/>FB, & </s> <s xml:id="echoid-s938" xml:space="preserve">c’eſt par cette même raiſon que nous avons regardé ci-<lb/>devant la ligne BD, comme un bras de lévier, dans la longueur <lb/>duquel étoit apliqué un nombre de puiſſances, parce que cette li-<lb/>gne eſt égale à la perpendiculaire FS, & </s> <s xml:id="echoid-s939" xml:space="preserve">que par conſequent on <lb/>peut prendre l’un pour l’autre, nous aurons donc le lévier re-<lb/>courbé SFZ: </s> <s xml:id="echoid-s940" xml:space="preserve">ainſi nommant SF, ou CF, c; </s> <s xml:id="echoid-s941" xml:space="preserve">EF, d; </s> <s xml:id="echoid-s942" xml:space="preserve">l’épaiſſëur BC, <lb/>ou DE, y; </s> <s xml:id="echoid-s943" xml:space="preserve">le poids V, ſera. </s> <s xml:id="echoid-s944" xml:space="preserve">{cd/2} & </s> <s xml:id="echoid-s945" xml:space="preserve">le poids r, ſera cy, ſi l’on <lb/>réünit le poids V, au poids r, & </s> <s xml:id="echoid-s946" xml:space="preserve">qu’on multiplie leur ſomme par <lb/>le bras de lévier ZF, on aura un produit égal à celui de la puiſ-<lb/>ſance T, par ſon bras de lévier SF, avec lequel on formera cette <lb/>équation {cyy/2} + cdy + {cdd/3} = bcf, de laquelle dégageant l’incon- <pb o="34" file="0058" n="59" rhead="LA SCIENCE DES INGENIEURS,"/> nuë il viendra y = √2bf + {cdd/3}\x{0020} - d, qui donne ce que l’on cher-<lb/>che.</s> <s xml:id="echoid-s947" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s948" xml:space="preserve">J’ay abregé les opérations qu’il a falu faire pour trouver la valeur <lb/>de y, parce qu’elles ont été expliquées amplement dans l’Article <lb/>22: </s> <s xml:id="echoid-s949" xml:space="preserve">j’en uſerai ainſi dans la ſuite, quand il s’agira de la même for-<lb/>mule.</s> <s xml:id="echoid-s950" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div81" type="section" level="1" n="52"> <head xml:id="echoid-head64" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s951" xml:space="preserve">Il eſt bien aiſé à preſent de mettre en pratique ce quele Probléme <lb/>précédent vient de nous enſeigner, car la derniere équation nous <lb/>montrant que pour avoir la valeur de y, il faut doubler celle de la <lb/>puiſſance X, ajoûter le tiers du quarré de la ligne de talud, extraire <lb/>la racine quarrée de la ſomme de cette quantité, & </s> <s xml:id="echoid-s952" xml:space="preserve">en retrancher la <lb/>ligne de talud, ayant trouvé que bf, vaut 13 pieds 9 pouces 4 li-<lb/>gnes, 2bf, vaudront 27 pieds 6 pouces 8 lignes, & </s> <s xml:id="echoid-s953" xml:space="preserve">comme la li-<lb/>gne de talud EF, eſt de 3 pieds, qui eſt la cinquiéme partie de la <lb/>hauteur EC, ajoûtant donc à la valeur de 2bf, 3, qui eſt égal à <lb/>{dd/3} l’on aura 30 pieds 6 pouces 8 lignes, dont la racine quarrée <lb/>eſt 5 pieds 6 pouces 2 lignes, qui eſt l’épaiſſeur qu’il faut donner <lb/>à la baſe DF, du revétement; </s> <s xml:id="echoid-s954" xml:space="preserve">par conſequent ſi l’on en retranche <lb/>la valeur de la ligne de talud qui eſt 3 pieds, il reſtera 2 pieds 6 <lb/>pouces 2 lignes pour l’épaiſſeur du ſommet BC.</s> <s xml:id="echoid-s955" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s956" xml:space="preserve">En ſuivant la même régle, on trouvera qu’un revêtement de 20 <lb/>pieds de hauteur doit avoir au ſommet 3 pieds 3 pouces 5 lignes, <lb/>& </s> <s xml:id="echoid-s957" xml:space="preserve">ſur la retraite 7 pieds 3 pouces 5 lignes, qu’un autre de 30 pieds <lb/>doit avoir pour épaiſſeur au ſommet 4 pieds 9 pouces 8 lignes, <lb/>& </s> <s xml:id="echoid-s958" xml:space="preserve">ſur la retraite 10 pieds 9 pouces 8 lignes.</s> <s xml:id="echoid-s959" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div82" type="section" level="1" n="53"> <head xml:id="echoid-head65" xml:space="preserve">Remarque prémiere.</head> <p> <s xml:id="echoid-s960" xml:space="preserve">33. </s> <s xml:id="echoid-s961" xml:space="preserve">On voit que la valeur de y, eſt un tant ſoit peu plus grande qu’el-<lb/>le ne devroit être naturellement, car quand nous avons ſupoſé que <lb/>l’effort du triangle HGB, étoit réüni au point B, l’on a donné un <lb/>peu plus de force à ce triangle qu’il ne devoit en avoir, parce <lb/>qu’agiſſant le long de la ligne BH, ſon action diminuë à meſure <lb/>qu’elle aproche du point H, le bras de lévier n’étant plus ſi grand; <lb/></s> <s xml:id="echoid-s962" xml:space="preserve">c’eſt-à-dire, par exemple, que le triangle ne faiſant point autant <lb/>d’effort au point I, qu’au point B, à cauſe que le bras de lévier <lb/>ID, eſt plus petit que BD, on a augmenté la force qui agit au <pb o="35" file="0059" n="60" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> point I, en la ſupoſant en B, de la difference qu’il y a du bras ID, <lb/>au bras BD, ainſi de tous les autres points de la ligne BH, & </s> <s xml:id="echoid-s963" xml:space="preserve"><lb/>comme nous avons agi de même pour les Trapezes qui ſont après <lb/>le triangle, en ſupoſant leur effort réüni aux points HN, &</s> <s xml:id="echoid-s964" xml:space="preserve">c, l’on <lb/>voit que toutes les differences des bras de léviers jointes enſem-<lb/>ble donnent un peu plus de force à la puiſſance qu’elle ne devroit <lb/>avoir, mais ceci n’eſt pas un deffaut, car la puiſſance étant un <lb/>peu au-deſſus de ce qu’elle doit être, il faudra donner au revête-<lb/>ment un peu plus d’épaiſſeur qu’il n’en faudroit pour un parfait <lb/>équilibre, & </s> <s xml:id="echoid-s965" xml:space="preserve">c’eſt ce qu’il faut abſolument puiſque quand même <lb/>l’on auroit touvé dans la derniere juſteſſe ce point d’équilibre, <lb/>il faudroit toûjours donner plus d’avantage à la puiſſance reſiſtante <lb/>qu’à celle qui agit, ainſi le calcul précédent eſt fort bon dans la <lb/>pratique, cependant cela n’empêche pas que l’on ne puiſſe quand <lb/>on voudra trouver la valeur de y, la plus aprochante qu’il eſt poſ-<lb/>ſible, en diviſant la hauteur du Mur en un ſi grand nombre de <lb/>parties que la difference des bras de léviers ſoit fort petite; </s> <s xml:id="echoid-s966" xml:space="preserve">on en <lb/>ſera quitte pour faire un calcul beaucoup plus long que le précé-<lb/>dent, mais ce ſeroit s’arrêter à la vetille que d’y prendre garde de <lb/>ſi près. </s> <s xml:id="echoid-s967" xml:space="preserve">Ainſi on ne peut mieux faire que de donner toûjours aux <lb/>progreſſions des puiſſances & </s> <s xml:id="echoid-s968" xml:space="preserve">des léviers, autant de termes qu’il <lb/>y a de pieds dans la hauteur du Mur.</s> <s xml:id="echoid-s969" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div83" type="section" level="1" n="54"> <head xml:id="echoid-head66" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s970" xml:space="preserve">34. </s> <s xml:id="echoid-s971" xml:space="preserve">Je n’ai fait la Remarque précédente, que pour ſatisfaire la dé-<lb/>licateſſe de ceux qui aiment que tout ce qui ſe raporte aux Mathé-<lb/>matiques ſoit toûjours dans la derniere juſteſſe, mais ſi l’on fait <lb/>attention que quand il s’agit de choſes de pratique il faut quelque-<lb/>fois s’écarter d’une trop grande preciſion, crainte qu’elle ne de-<lb/>vienne nuiſible à ce que l’on veut executer, l’on verra que dans <lb/>le ſujet dont il eſt ici queſtion, on auroit tort de faire des revête-<lb/>mens qui fuſſent parfaitement en équilibre avec la pouſſée des <lb/>Terres, ſur-tout quand ils ſervent pour des Chauſſées, des Quays, <lb/>&</s> <s xml:id="echoid-s972" xml:space="preserve">c. </s> <s xml:id="echoid-s973" xml:space="preserve">puiſque dans ce cas ils doivent non-ſeulement ſoûtenir les <lb/>Terres, mais encore le poids des Voitures & </s> <s xml:id="echoid-s974" xml:space="preserve">l’ébranlement qu’el-<lb/>les peuvent cauſer; </s> <s xml:id="echoid-s975" xml:space="preserve">c’eſt pourquoi quand on n’y fera pas des con-<lb/>treforts, je voudrois qu’on leur donnàt un quart plus de force qu’il <lb/>ne leur en faudroit dans l’état d’équilibre, je veux dire que s’il <lb/>s’agiſloit, par exemple, d’un Mur de 15 pieds, la puiſſance bf, au <lb/>lieu de valoir 13 pieds 9 pouces 4 lignes, doit être de 17 pieds <pb o="36" file="0060" n="61" rhead="LA SCIENCE DES INGENIEURS,"/> 2 pouces 8 lignes, ce qui donnera 3 pieds un pouce pour l’épaiſ-<lb/>ſeur du ſommet BC, & </s> <s xml:id="echoid-s976" xml:space="preserve">6 pieds un pouce pour la baſe DF.</s> <s xml:id="echoid-s977" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div84" type="section" level="1" n="55"> <head xml:id="echoid-head67" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s978" xml:space="preserve">Ayant fait ſentir dans pluſieurs endroits de ce Livre, & </s> <s xml:id="echoid-s979" xml:space="preserve">parti-<lb/>culierement à l’Article 23. </s> <s xml:id="echoid-s980" xml:space="preserve">combien le talud qu’on donnoit au <lb/>parement d’un Mur le fortifioit contre l’effort qu’il avoit à ſoûte-<lb/>nir, j’ai crû devoir raporter ici un profil de Rempart aſſés ſingulier <lb/>imaginé depuis peu par des gens qui n’ont peut-être point fait <lb/>aſſés d’attention ſur la maniere dont ſe faiſoit la pouſſée des Terres; <lb/></s> <s xml:id="echoid-s981" xml:space="preserve">voici de quoi il eſt queſtion.</s> <s xml:id="echoid-s982" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s983" xml:space="preserve">Pour ne point trop expoſer un revêtement aux injures des Sai-<lb/>ſons, leur ſentiment eſt de faire le parement à plomb & </s> <s xml:id="echoid-s984" xml:space="preserve">lui don-<lb/>ner un talud du côté des Terres, dans la penſée que s’apuyant ſur ce <lb/>talud, il y en auroit une partie qui contre-balanceroit la pouſſée <lb/>de l’autre; </s> <s xml:id="echoid-s985" xml:space="preserve">pour en juger, il faut du point A, tirer la perpendiculaire <lb/> <anchor type="note" xlink:label="note-0060-01a" xlink:href="note-0060-01"/> AE, à la ligne HD, & </s> <s xml:id="echoid-s986" xml:space="preserve">faire EF, égalà cette perpendiculaire, afin <lb/>d’avoir le triangle AEF, qui renfermera toutes les Terres qui agiſ-<lb/>ſent contre la ligne EA, que nous regarderons pour un moment <lb/>comme une ſurface; </s> <s xml:id="echoid-s987" xml:space="preserve">dans ce cas il n’y a point de doute que ſi <lb/>la ligne EA, étoit le derriere du revêtement, la pouſſée ne ſe fit <lb/>comme à l’ordinaire: </s> <s xml:id="echoid-s988" xml:space="preserve">il s’agit donc de ſavoir ſi celles qui ſont ren-<lb/>fermées dans le triangle EAD, ſoulagent le revêtement, ou ſi au <lb/>contraire elles ſe joignent aux autres pour en augmenter la pouſſée. <lb/></s> <s xml:id="echoid-s989" xml:space="preserve">Si l’on diviſe la ligne EA, en autant de parties égales que la hau-<lb/>teur du revêtement contient de pieds, & </s> <s xml:id="echoid-s990" xml:space="preserve">que l’on faſſe les Trapezes <lb/>des puiſſances comme à l’ordinaire, il eſt conſtant qu’en prolon-<lb/>geant toutes les paralelles au-delà de la ligne EA, juſqu’à la ren-<lb/>contre de la face DA, toutes les puiſſances contenuës depuis F, <lb/>juſqu’en E, ſe trouveront augmentées par les nouveaux Trapezes <lb/>qui regnent depuis I, juſqu’en A, les unes plus, les autres moins, <lb/>il y aura cela de particulier que les puiſſances, qui auront les plus <lb/>grands bras de lévier, ſeront juſtement celles qui auront reçûës <lb/>le plus d’augmentation, or ſi dans cette augmentation generale <lb/>on y comprend encore le petit triangle EDI, qui ſera de conſé-<lb/>quence à cauſe qu’il agit vers le ſommet de la muraille, il ſaute <lb/>aux yeux que le triangle AED, bien loin d’affermir le revêtement <lb/>contre la pouſſée des Terres qui ſont derriere la ligne AE, ne fait <lb/>que le charger beaucoup plus qu’il ne le ſeroit ſi le Mur étoit à <lb/>plomb de ce côté-là. </s> <s xml:id="echoid-s991" xml:space="preserve">On pourroit même déterminer avec aſſés de <pb o="37" file="0061" n="62" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> préciſion à quoi peut aller cette nouvelle pouſſée, mais ce ſeroit <lb/>perdre du tems mal-à-propos.</s> <s xml:id="echoid-s992" xml:space="preserve"/> </p> <div xml:id="echoid-div84" type="float" level="2" n="1"> <note position="left" xlink:label="note-0060-01" xlink:href="note-0060-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 5.</note> </div> <p> <s xml:id="echoid-s993" xml:space="preserve">On remarquera ſeulement, qu’en ne donnant point de talud aux <lb/>revêtemens de Fortification, il n’y a point de doute qu’étant bat-<lb/>tus en brêche, la deſtruction ne ſe faſſe plûtôt par la facilité que <lb/>les débris auront de s’ébouler; </s> <s xml:id="echoid-s994" xml:space="preserve">d’un autre côté, dans les Pays où la <lb/>Maçonnerie n’eſt pas bien bonne, & </s> <s xml:id="echoid-s995" xml:space="preserve">où les revêtemens ſont ſujets <lb/>à ſurplomber ou à ſoufler, on s’aperçevroit bien-tôt du mauvais <lb/>effet de ce ſyſtême, qui, à ce que je crois, n’aura pas beaucoup de <lb/>Partiſans.</s> <s xml:id="echoid-s996" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div86" type="section" level="1" n="56"> <head xml:id="echoid-head68" xml:space="preserve">PROPOSITION SECONDE. <lb/><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s997" xml:space="preserve">35. </s> <s xml:id="echoid-s998" xml:space="preserve">Trouver quelle épaiſſeur il faut donner aux revêtemens <lb/>des Rempars de Fortificatïon qui ſont accompagnés d’un <lb/>Parapet.</s> <s xml:id="echoid-s999" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1000" xml:space="preserve">Nous n’avons parlé juſqu’ici que de l’épaiſſeur des Murs qui ſoû-<lb/>tenoient des Terraſſes, & </s> <s xml:id="echoid-s1001" xml:space="preserve">non pas de ceux qui ſervent de revête-<lb/>mens aux Rempars des Fortifications: </s> <s xml:id="echoid-s1002" xml:space="preserve">il y a des gens qui croyent <lb/>que c’eſt à peu-prês la même choſe, mais il y a bien de la diffe-<lb/>rence; </s> <s xml:id="echoid-s1003" xml:space="preserve">car comme on éleve toûjours ſur ces ſortes de Rempars un <lb/>Parapet de Terre qui fortifie la pouſſée de celles qui ſont déja der-<lb/>riere le revêtement, l’on ſent bien que ces revêtemens-ci doivent <lb/>avoir plus d’épaiſſeur que ceux de Terraſſes: </s> <s xml:id="echoid-s1004" xml:space="preserve">il eſt vrai qu’il y a un <lb/>peu de difficulté à trouver de combien le Parapet augmente cette <lb/>pouſſée, mais l’on va voir qu’on en peut rendre le calcul auſſi aiſé <lb/>que le précédent.</s> <s xml:id="echoid-s1005" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1006" xml:space="preserve">Ayant pris KD, égal à DB, conſiderés la premiere ligne comme <lb/> <anchor type="note" xlink:label="note-0061-01a" xlink:href="note-0061-01"/> marquant le niveau du Rempart, deſſus lequel l’on a élevé la Ban-<lb/>quette & </s> <s xml:id="echoid-s1007" xml:space="preserve">le Parapet IGEQ, ſoûtenu par un petit revêtement EC, <lb/>auquel l’on donne ordinairement 4 pieds de hauteur ſur 3 d’épaiſ-<lb/>ſeur; </s> <s xml:id="echoid-s1008" xml:space="preserve">ſi l’on diviſe la ligne BD, en autant de parties égales qu’il <lb/>y a de pieds dans la hauteur du revêtement, & </s> <s xml:id="echoid-s1009" xml:space="preserve">que l’on tire toutes <lb/>les lignes comme ST, VX &</s> <s xml:id="echoid-s1010" xml:space="preserve">c. </s> <s xml:id="echoid-s1011" xml:space="preserve">paralelles à KB, elles formeront <lb/>des Trapezes comme dans la figure précédente, & </s> <s xml:id="echoid-s1012" xml:space="preserve">ſi l’on prolonge <lb/>toutes ces paralelles juſqu’à la rencontre des lignes qui renferment <lb/>le Parapet & </s> <s xml:id="echoid-s1013" xml:space="preserve">la Banquette, l’on aura un grand nombre de nouveaux <lb/>Trapezes, dont chacun pourra être regardé comme la quantité <lb/>dont la puiſſance qui lui répond eſt augmentée. </s> <s xml:id="echoid-s1014" xml:space="preserve">Cela poſé, il faut <pb o="38" file="0062" n="63" rhead="LA SCIENCE DES INGENIEURS,"/> conſiderer d’abord qu’il y a le long de la ligne EQ, trois Trapezes <lb/>& </s> <s xml:id="echoid-s1015" xml:space="preserve">un triangle dont l’action doit être ſupoſée réünie aux points E, M, <lb/>O, N, extrêmités des bras de léviers AE, AM, AO, AN, & </s> <s xml:id="echoid-s1016" xml:space="preserve">com-<lb/>me l’effort de chacun de ces Trapezes doit être reduit à l’extrêmité <lb/>D, du bras de lévier BD, il faut multiplier l’expreſſion de la force <lb/>dont chacun eſt capable par ſon bras de lévier, & </s> <s xml:id="echoid-s1017" xml:space="preserve">pour trouver <lb/>cette expreſſion il n’y a qu’à voir le rapport du petit triangle DST, <lb/>à chaque Trapeze, ainſi ſupoſant que le Trapeze LM, ſoit qua-<lb/>druple du petit triangle, la pouſſée de ce petit triangle étant nom-<lb/>mée b, comme ci-devant, celle du Trapeze LM, ſera 46, & </s> <s xml:id="echoid-s1018" xml:space="preserve">l’on <lb/>trouvera de même la pouſſée des trois autres Trapezes ſuivans; <lb/></s> <s xml:id="echoid-s1019" xml:space="preserve">après cela il faut multiplier chacune de ces puiſſances par le bras de <lb/>lévier qui lui répond & </s> <s xml:id="echoid-s1020" xml:space="preserve">écrire les quatre produits à part pour les a-<lb/>joûter quand il ſera tems, avec les autres que nous allons trouver. </s> <s xml:id="echoid-s1021" xml:space="preserve"><lb/>Il faut encore chercher le raport du petit triangle DST, avec tous <lb/>les autres Trapezes PQ, RD, rS, &</s> <s xml:id="echoid-s1022" xml:space="preserve">c. </s> <s xml:id="echoid-s1023" xml:space="preserve">qui regnent depuis Q, juſ-<lb/>qu’en I, au-deſſus de la ligne DK, afin de voir combien chacun <lb/>contient de fois la puiſſance b, enſuite écrire la progreſſion de <lb/>toutes les puiſſances qui ſont au-deſſous de la ligne DK, comme <lb/>on a fait dans l’Article 32. </s> <s xml:id="echoid-s1024" xml:space="preserve">l’on aura b, 3b. </s> <s xml:id="echoid-s1025" xml:space="preserve">5b. </s> <s xml:id="echoid-s1026" xml:space="preserve">7b. </s> <s xml:id="echoid-s1027" xml:space="preserve">9b. </s> <s xml:id="echoid-s1028" xml:space="preserve">11b. </s> <s xml:id="echoid-s1029" xml:space="preserve">&</s> <s xml:id="echoid-s1030" xml:space="preserve">c. </s> <s xml:id="echoid-s1031" xml:space="preserve"><lb/>& </s> <s xml:id="echoid-s1032" xml:space="preserve">voir combien chaque terme doit être augmenté, par exemple, <lb/>comme le petit triangle DST, eſt augmenté de tout le Trapeze <lb/>RD, on doit regarder le Trapeze PT, comme la puiſſance qui <lb/>agit au point D, & </s> <s xml:id="echoid-s1033" xml:space="preserve">le Trapeze PQ, agiſſant auſſi autour du point <lb/>D, le premier terme de la progreſſion doit être augmenté d’au-<lb/>tant d’unités que la puiſſance b, eſt contenue de fois dans les deux <lb/>Trapezes PT, & </s> <s xml:id="echoid-s1034" xml:space="preserve">PQ, de même le ſecond terme exprimant le <lb/>Trapeze SX, doit être augmenté d’autant d’unités que la puiſſan-<lb/>ce b, eſt contenue de fois dans RV, ainſi des autres qui doivent <lb/>augmenter ſelon que les Trapezes qui leur répondent dans la fi-<lb/>gure contiennent plus ou moins la puiſſance b, juſqu’à ce que l’on <lb/>ſoit parvenu au point I, parce que pour lors ſi le triangle KDB, <lb/>contient encore quelques puiſſances qui ne ſoient point augmentées <lb/>dans la figure, elles ne doivent pas l’être non plus dans la pro-<lb/>greſſion, & </s> <s xml:id="echoid-s1035" xml:space="preserve">par conſequent les termes qui leur répondent doivent <lb/>être écrits comme à l’ordinaire.</s> <s xml:id="echoid-s1036" xml:space="preserve"/> </p> <div xml:id="echoid-div86" type="float" level="2" n="1"> <note position="right" xlink:label="note-0061-01" xlink:href="note-0061-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> <p> <s xml:id="echoid-s1037" xml:space="preserve">Après qu’on aura écrit de ſuite toutes les puiſſances qui agiſ-<lb/>ſent le long de la ligne DB, & </s> <s xml:id="echoid-s1038" xml:space="preserve">qui exprimeront par conſequent la <lb/>pouſſée des Terres du Rempart & </s> <s xml:id="echoid-s1039" xml:space="preserve">du Parapet à l’exception de celles <lb/>qui agiſſent derriere la ligne EQ, il faudra les multiplier par leur <lb/>bras de léviers comme à l’ordinaire, & </s> <s xml:id="echoid-s1040" xml:space="preserve">ajoûter à la ſomme de tous <pb o="39" file="0063" n="64" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> les produits, les quatre que nous avons trouvé d’abord au ſujet du <lb/>petit revêtement EC, aprés cela l’on aura l’effet total de toutes <lb/>les puiſſances qui agiſſent derriere le revêtement EQDB, qui étant <lb/>diviſé par la hauteur DB, le quotient donnera la pouſſée des Ter-<lb/>res, ou ſi l’on veut toutes les puiſſances réünies à l’extrêmité D, <lb/>du bras de lévier BD; </s> <s xml:id="echoid-s1041" xml:space="preserve">de ſorte que s’il s’agit d’un revêtement dont <lb/>la hauteur BD, ſoit de 25 pieds, l’on trouvera que la ſomme de <lb/>toutes les puiſſances réünies au point D, ſera de 342b{2/3}, & </s> <s xml:id="echoid-s1042" xml:space="preserve">ſu-<lb/>poſant 342 {2/3} = f, on aura donc la valeur de bf, qui eſt la puiſ-<lb/>ſance avec laquelle il faut que le revêtement ſoit en équilibre.</s> <s xml:id="echoid-s1043" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1044" xml:space="preserve">Preſentement voulant trouver l’épaiſſeur DC, ou BZ, nous la <lb/>nommerons y; </s> <s xml:id="echoid-s1045" xml:space="preserve">QC, a; </s> <s xml:id="echoid-s1046" xml:space="preserve">FC, g; </s> <s xml:id="echoid-s1047" xml:space="preserve">la hauteur CZ, c; </s> <s xml:id="echoid-s1048" xml:space="preserve">& </s> <s xml:id="echoid-s1049" xml:space="preserve">la ligne de <lb/>talud ZH, d; </s> <s xml:id="echoid-s1050" xml:space="preserve">cela poſé, il faut réduire la figure QEFC, que nous <lb/>conſidererons comme un rectangle, à n’avoir qu’une même épaiſ-<lb/>ſeur BC, avec le rectangle BDCZ; </s> <s xml:id="echoid-s1051" xml:space="preserve">pour cela il faut diviſer ſa <lb/>ſuperficie qui eſt ag, par la ligne DC, (y) & </s> <s xml:id="echoid-s1052" xml:space="preserve">on aura {ag/y} pour <lb/>la hauteur dont le rectangle DZ, doit être augmenté pour que le <lb/>petit revêtement EC, ſoit uni avec le rectangle DZ; </s> <s xml:id="echoid-s1053" xml:space="preserve">ainſi multi-<lb/>pliant y par {ag/y} + c, l’on aura ag + cy, égal à toute la ſuper-<lb/>ficie BDQEFZ, que nous ſupoſerons réünie au poids qui eſt ſuſ-<lb/>pendu dans le milieu de la ligne BZ, auquel joignant comme à <lb/>l’ordinaire le poids 3 & </s> <s xml:id="echoid-s1054" xml:space="preserve">multipliant leur ſomme par le bras de lé-<lb/>vier H 4, il viendra un produit égal à celui de la puiſſance bf, par <lb/>ſon bras de lévier BD, ou H 5, d’où l’on tire cette équation <lb/>{yyc/2} + {agy/2} + cdy + agd + {cdd/3} = bfc, qui eſt un peu compoſé, mais <lb/>qui n’eſt pourtant pas difficile à réduire, car ſi l’on change {ag/2} <lb/>+ cd, en un rectangle qui ait pour une de ſes dimenſions la gran-<lb/>deur c, & </s> <s xml:id="echoid-s1055" xml:space="preserve">que l’autre dimenſion ait été trouvée égale à n, l’on <lb/>aura {ag/2} + cd = cn, par conſequent {agy/2} + cdy = cny, or met-<lb/>tant dans l’équation précédente cny, à la place de ſa valeur, l’on <lb/>aura {cyy/2} + cny + agd + {cdd/3} = bfc, de laquelle faiſant évanoüir <lb/>la fraction du premier terme, & </s> <s xml:id="echoid-s1056" xml:space="preserve">diviſant le tout par c, l’on aura yy <lb/>+ 2ny + {2agd/c} + {2dd/3} = 2bf, ou bien yy + 2ny = 2bf - {2agd/c} <pb o="40" file="0064" n="65" rhead="LA SCIENCE DES INGENIEURS,"/> - {2dd/3} à quoi ajoûtant nn, de part & </s> <s xml:id="echoid-s1057" xml:space="preserve">d’autre, pour rendre le pre-<lb/>mier membre un quarré parfait, il viendra yy + 2ny + nn = 2bf <lb/>- {2agd/c} - {2dd/3} + nn, dont extrayant la racine quarrée, l’on aura <lb/>enfin y = √2bf - {2agd/c} - {2dd/3} + nn\x{0020} - n, qui donne 5 pieds 8 pou-<lb/>ces & </s> <s xml:id="echoid-s1058" xml:space="preserve">environ 8 lignes pour la valeur de y.</s> <s xml:id="echoid-s1059" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1060" xml:space="preserve">Comme cette opération eſt un peu longue, ſur-tout pour con-<lb/>noître la valeur de y, il vaut beaucoup mieux dans la pratique <lb/>faire abſtraction du petit revêtement EC, & </s> <s xml:id="echoid-s1061" xml:space="preserve">ne le pas admettre <lb/>dans le calcul Algebrique, & </s> <s xml:id="echoid-s1062" xml:space="preserve">pour lors l’on aura comme à l’or-<lb/>dinaire l’équation y = √2bf + {dd/3}\x{0020} - d, qui eſt beaucoup plus <lb/>ſimple. </s> <s xml:id="echoid-s1063" xml:space="preserve">Il eſt vrai que le poids qui exprime la péſanteur de tout <lb/>le revêtement ſera plus léger qu’il ne devroit être de la partie <lb/>EC, mais ce n’eſt point un mal: </s> <s xml:id="echoid-s1064" xml:space="preserve">au contraire, puiſque l’épaiſſeur <lb/>DC, en ſera un tant ſoit peu plus grande qu’il ne faudroit pour <lb/>un parfait équilibre, il ſemble même qu’on pourroit me reprocher <lb/>de donner dans une trop grande préciſion pour un ſujet qui de <lb/>lui-même demande d’être traité plus cavalierement, car l’épaiſſeur <lb/>qu’on trouvera de plus, en omettant le petit revêtement, ne paſſe <lb/>pas 8 ou 9 lignes, comme on le va voir.</s> <s xml:id="echoid-s1065" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div88" type="section" level="1" n="57"> <head xml:id="echoid-head69" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s1066" xml:space="preserve">Ne faiſant point mention, comme je viens de le dire, du petit <lb/>revêtement EC, il ne s’agit plus pour avoir l’épaiſſeur DC, en nom-<lb/>bres, que de calculer l’équation y = √2bf + {dd/3}\x{0020} - d, pour ce-<lb/>la il faut ſe rapeller que l’on a trouvé que f, valoit 342 {2/3}, qu’il <lb/>faut multiplier par la valeur de b, qui eſt 3 pouces, parce que <lb/>le petit triangle DST, vaut 6 pouces, & </s> <s xml:id="echoid-s1067" xml:space="preserve">qu’il n’y en a que la moi-<lb/>tié qui agit contre la ſurface DT, ou comme on l’a ſupoſé, contre <lb/>le point D, & </s> <s xml:id="echoid-s1068" xml:space="preserve">l’on aura 85 pieds 8 pouces pour la valeur de bf, <lb/>mais comme bf, doit être diminué d’un tiers à cauſe que cette <lb/>grandeur exprime la valeur d’une ſuperficie de Terre par l’Article <lb/>5, il faut donc prendre les deux tiers de 85 pieds 8 pouces, pour <lb/>avoir 57 pieds un pouce 4 lignes pour la valeur de bf, réduite, <lb/>c’eſt-à-dire pour qu’elle puiſſe entrer dans le calcul de la Maçonne- <pb o="41" file="0065" n="66" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> rie. </s> <s xml:id="echoid-s1069" xml:space="preserve">Or comme dans la formule, bf, eſt multiplié par 2, il faut auſſi <lb/>doubler 57 pieds un pouce 4 lignes pour avoir 114 pieds 2 pouces <lb/>8 lignes, à quoi ajoûtant le tiers du quarré de la ligne de talud, <lb/>qui eſt 8 pieds 4 pouces, l’on aura 122 pieds 6 pouces 8 lignes, <lb/>dont la racine quarrée eſt 11 pieds 10 pouces pour l’épaiſſeur BH, <lb/>ſur la retraite, d’où retranchant la ligne de talud qui eſt 5 pieds, <lb/>l’on trouvera 6 pieds 10 lignes pour l’épaiſſeur DC, que le Mur doit <lb/>avoir au ſommet; </s> <s xml:id="echoid-s1070" xml:space="preserve">& </s> <s xml:id="echoid-s1071" xml:space="preserve">comme l’on n’a trouvé que 6 pieds 2 lignes, <lb/>il s’enſuit, comme je l’ai inſinué, que la difference eſt 8 lignes.</s> <s xml:id="echoid-s1072" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div89" type="section" level="1" n="58"> <head xml:id="echoid-head70" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s1073" xml:space="preserve">36. </s> <s xml:id="echoid-s1074" xml:space="preserve">L’on voit qu’en ſuivant ce que je viens d’enſeigner, on peut <lb/>trouver avec aſſés de préciſion la pouſſée des terres, qui compoſent <lb/>le Rempart & </s> <s xml:id="echoid-s1075" xml:space="preserve">le Parapet: </s> <s xml:id="echoid-s1076" xml:space="preserve">On pourroit ſeulement ſe plaindre que <lb/>c’eſt un travail un peu long de calculer la valeur de tous les Tra-<lb/>pezes qui ſont au-deſſus de la ligne DK, à cauſe qu’ils ſont irrégu-<lb/>liers, c’eſt pourquoi j’ai cherché une voye plus abregée, & </s> <s xml:id="echoid-s1077" xml:space="preserve">j’en <lb/>ai trouvé une qui rend les opérations tout auſſi aiſées, que s’il n’y <lb/>avoit point de Parapet; </s> <s xml:id="echoid-s1078" xml:space="preserve">la voici.</s> <s xml:id="echoid-s1079" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1080" xml:space="preserve">Il faut commencer par faire abſtraction de tout ce qui eſt au-<lb/>deſſus de la ligne KC, c’eſt-à-dire qu’il ne faut conſiderer que le <lb/>triangle de terre KDB, & </s> <s xml:id="echoid-s1081" xml:space="preserve">le profil de la maçonnerie BDCH, comme <lb/> <anchor type="note" xlink:label="note-0065-01a" xlink:href="note-0065-01"/> s’il s’agiſſoit d’un revêtement de Terraſſe, ainſi que dans l’Art. </s> <s xml:id="echoid-s1082" xml:space="preserve">32. <lb/></s> <s xml:id="echoid-s1083" xml:space="preserve">enſuite écrire la progreſſion des puiſſances en lui donnant autant <lb/>de termes que la hauteur DB, contient de pieds, & </s> <s xml:id="echoid-s1084" xml:space="preserve">ſupoſant qu’elle <lb/>en contienne 25, j’écris 1b. </s> <s xml:id="echoid-s1085" xml:space="preserve">3b. </s> <s xml:id="echoid-s1086" xml:space="preserve">5b. </s> <s xml:id="echoid-s1087" xml:space="preserve">7b. </s> <s xml:id="echoid-s1088" xml:space="preserve">9b. </s> <s xml:id="echoid-s1089" xml:space="preserve">11b. </s> <s xml:id="echoid-s1090" xml:space="preserve">13b. </s> <s xml:id="echoid-s1091" xml:space="preserve">15b. </s> <s xml:id="echoid-s1092" xml:space="preserve">17b. </s> <s xml:id="echoid-s1093" xml:space="preserve">19b. </s> <s xml:id="echoid-s1094" xml:space="preserve"><lb/>21b. </s> <s xml:id="echoid-s1095" xml:space="preserve">23b. </s> <s xml:id="echoid-s1096" xml:space="preserve">25b. </s> <s xml:id="echoid-s1097" xml:space="preserve">27b. </s> <s xml:id="echoid-s1098" xml:space="preserve">29b. </s> <s xml:id="echoid-s1099" xml:space="preserve">31b. </s> <s xml:id="echoid-s1100" xml:space="preserve">33b. </s> <s xml:id="echoid-s1101" xml:space="preserve">35b. </s> <s xml:id="echoid-s1102" xml:space="preserve">37b. </s> <s xml:id="echoid-s1103" xml:space="preserve">39b. </s> <s xml:id="echoid-s1104" xml:space="preserve">41b. </s> <s xml:id="echoid-s1105" xml:space="preserve">43b. </s> <s xml:id="echoid-s1106" xml:space="preserve">45. </s> <s xml:id="echoid-s1107" xml:space="preserve">b. </s> <s xml:id="echoid-s1108" xml:space="preserve"><lb/>47b. </s> <s xml:id="echoid-s1109" xml:space="preserve">49b. </s> <s xml:id="echoid-s1110" xml:space="preserve">J’ajoûte dix unités à chacun des vingts premiers termes <lb/>de cette progreſſion pour avoir 11b. </s> <s xml:id="echoid-s1111" xml:space="preserve">13b. </s> <s xml:id="echoid-s1112" xml:space="preserve">15b. </s> <s xml:id="echoid-s1113" xml:space="preserve">17b. </s> <s xml:id="echoid-s1114" xml:space="preserve">19b. </s> <s xml:id="echoid-s1115" xml:space="preserve">21b. </s> <s xml:id="echoid-s1116" xml:space="preserve">23b. </s> <s xml:id="echoid-s1117" xml:space="preserve"><lb/>25b. </s> <s xml:id="echoid-s1118" xml:space="preserve">27b. </s> <s xml:id="echoid-s1119" xml:space="preserve">29b. </s> <s xml:id="echoid-s1120" xml:space="preserve">31b. </s> <s xml:id="echoid-s1121" xml:space="preserve">33b. </s> <s xml:id="echoid-s1122" xml:space="preserve">35b. </s> <s xml:id="echoid-s1123" xml:space="preserve">37b. </s> <s xml:id="echoid-s1124" xml:space="preserve">39b. </s> <s xml:id="echoid-s1125" xml:space="preserve">41b. </s> <s xml:id="echoid-s1126" xml:space="preserve">43b. </s> <s xml:id="echoid-s1127" xml:space="preserve">45b. </s> <s xml:id="echoid-s1128" xml:space="preserve">47b. </s> <s xml:id="echoid-s1129" xml:space="preserve">49b. </s> <s xml:id="echoid-s1130" xml:space="preserve"><lb/>dont les cinq derniers termes ſont les mêmes que dans la progreſſion <lb/>précédente, parce qu’ils n’ont pas été augmentés; </s> <s xml:id="echoid-s1131" xml:space="preserve">car, comme je <lb/>l’ai dit, il n’y a qu’aux vingt premiers termes qu’il faut ajoûter 10, <lb/>ſoit que le revêtement ait 30, 40, ou 50 pieds de hauteur, les au-<lb/>tres termes qui ſuivent les vingt premiers devant toûjours reſter <lb/>comme ſi on n’avoit fait aucun changement à la progreſſion; </s> <s xml:id="echoid-s1132" xml:space="preserve">je <lb/>multiplie préſentement chaque terme par ſon bras de lévier, com-<lb/>me à l’ordinaire, j’entens que le premier terme 11 b ſera multi-<lb/>plié par 25, le ſecond 13 b par 24, le troiſiéme 15 b par 23, & </s> <s xml:id="echoid-s1133" xml:space="preserve"><lb/>ainſi des autres; </s> <s xml:id="echoid-s1134" xml:space="preserve">car je ne fais aucun changement dans la progreſſion <pb o="42" file="0066" n="67" rhead="LA SCIENCE DES INGENIEURS,"/> des nombres naturels qui expriment la longueur des léviers, toutes <lb/>les multiplications étant faites, la ſomme des produits ſera 8625 b. <lb/></s> <s xml:id="echoid-s1135" xml:space="preserve">qui étant diviſé par 25, le quotient donnera 345 b. </s> <s xml:id="echoid-s1136" xml:space="preserve">ainſi f, qui dans <lb/>l’Art. </s> <s xml:id="echoid-s1137" xml:space="preserve">25, étoit de 342 {2/3} ſera ici de 345, ce qui fait environ <lb/>2 unités de plus, par conſéquent dans l’équation y = √2bf + {dd/3}\x{0020} <lb/>- d, bf, au lieu de valoir 57 pieds un pouce 4 lignes, vaudra 57 <lb/>pieds 6 pouces, qui donne environ 5 pouces de plus, & </s> <s xml:id="echoid-s1138" xml:space="preserve">continuant <lb/>le reſte de l’opération, je trouve que y, vaut 6 pieds un pouce 2 li-<lb/>gnes, au lieu qu’elle n’a été trouvée dans l’Article précédent que <lb/>de 6 pieds 10 lignes, ce qui fait une difference de 4 lignes.</s> <s xml:id="echoid-s1139" xml:space="preserve"/> </p> <div xml:id="echoid-div89" type="float" level="2" n="1"> <note position="right" xlink:label="note-0065-01" xlink:href="note-0065-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> <p> <s xml:id="echoid-s1140" xml:space="preserve">J’ai cherché, ſelon ces deux methodes, l’épaiſſeur qu’il falloit <lb/>donner au ſommet de pluſieurs revêtemens, les prenant à des hau-<lb/>teurs arbitraires, j’ai trouvé que mes opérations donnoient la mê-<lb/>me choſe pour la valeur de y, à trois ou quatre lignes près, qui <lb/>eſt une difference de ſi peu de conſequence, qu’il m’a paru qu’il <lb/>valoit beaucoup mieux ſuivre cette méthode-ci que l’autre.</s> <s xml:id="echoid-s1141" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1142" xml:space="preserve">On demandera peut-être la raiſon qui m’a fait ajoûter dix unités aux <lb/>20 premiers termes de la progreſſion, mais je n’en ai d’autres à don-<lb/>ner, ſinon que je me ſuis aperçû, après avoir beaucoup cherché, <lb/>que ces dix unités, ajoûtées de ſuite, faiſoient une compenſation <lb/>pour les puiſſances & </s> <s xml:id="echoid-s1143" xml:space="preserve">les léviers, qui donnoient la même choſe <lb/>que les Trapezes qui ſont au-deſſus de la ligne KC, qui compo-<lb/>ſent le Parapet, quoique ces Trapezes allaſſent tantôt en augmen-<lb/>tant, tantôt en diminuant: </s> <s xml:id="echoid-s1144" xml:space="preserve">auſſi ne faut-il regarder cet abregé que <lb/>comme un moyen qui n’eſt bon que dans la pratique, & </s> <s xml:id="echoid-s1145" xml:space="preserve">dont on <lb/>peut ſe ſervir auſſi utilement que de la méthode que j’ai expliquée <lb/>dans l’Art. </s> <s xml:id="echoid-s1146" xml:space="preserve">35. </s> <s xml:id="echoid-s1147" xml:space="preserve">ſans laquelle je n’aurois pas trouvé celle-ci.</s> <s xml:id="echoid-s1148" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div91" type="section" level="1" n="59"> <head xml:id="echoid-head71" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s1149" xml:space="preserve">On ne pratique plus guére des revêtemens de Maçonnerie au-<lb/>deſſus du cordon, pour ſoûtenir les terres du Parapet, parce qu’on <lb/>s’eſt aperçû que les éclats, que cauſoit cette Maçonnerie quand elle <lb/> <anchor type="note" xlink:label="note-0066-01a" xlink:href="note-0066-01"/> étoit battuë du Canon, devenoient nuiſibles à ceux qui étoient <lb/>derriere le Parapet; </s> <s xml:id="echoid-s1150" xml:space="preserve">d’ailleurs, qu’il falloit plus de tems & </s> <s xml:id="echoid-s1151" xml:space="preserve">de diffi-<lb/>culté pour percer les embraſures en tems de ſiége, que ſi ce Pa-<lb/>rapet n’étoit revêtu que de gazons ou de placage ſur les deux tiers <lb/>de talud, qui eſt le parti que l’on prend ajourd’hui: </s> <s xml:id="echoid-s1152" xml:space="preserve">pour cela l’on <lb/>éloigne un peu le pied du Parapet du ſommet de la muraille, afin <pb o="43" file="0067" n="68" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> qu’il ſe ſoûtienne mieux, comme on le voit dans la 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s1153" xml:space="preserve">Figure; <lb/></s> <s xml:id="echoid-s1154" xml:space="preserve">mais, que le Parapet ſoit revêtu ou non, la méthode que je viens de <lb/>donner, pour calculer la pouſſée des Terres, ſera toûjours la même <lb/>auſſi-bien que pour les demi revêtements.</s> <s xml:id="echoid-s1155" xml:space="preserve"/> </p> <div xml:id="echoid-div91" type="float" level="2" n="1"> <note position="left" xlink:label="note-0066-01" xlink:href="note-0066-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> </div> <div xml:id="echoid-div93" type="section" level="1" n="60"> <head xml:id="echoid-head72" xml:space="preserve">USAGE D’UNE TABLE</head> <head xml:id="echoid-head73" style="it" xml:space="preserve">Pour trouver l’épaiſſeur qu’il faut donner aux Revêtemens de <lb/>Terraſſes & à ceux des Rempars de Fortification.</head> <p> <s xml:id="echoid-s1156" xml:space="preserve">37. </s> <s xml:id="echoid-s1157" xml:space="preserve">Comme il y a des gens qui pourroient ſe trouver embaraſſés <lb/>de ſe ſervir des Régles que j’ai enſeignées au ſujet des revêtemens <lb/>des Terraſſes & </s> <s xml:id="echoid-s1158" xml:space="preserve">des Rempars, faute de bien entendre les raiſons <lb/>ſur leſquelles elles ſont établies, j’ai crû qu’il étoit à propos de <lb/>donner une Table qui les diſpenſât de faire de longs & </s> <s xml:id="echoid-s1159" xml:space="preserve">pénibles <lb/>calculs, dans leſquels il eſt toûjours dangereux de ſe tromper, à <lb/>moins qu’on n’y aporte une grande attention; </s> <s xml:id="echoid-s1160" xml:space="preserve">& </s> <s xml:id="echoid-s1161" xml:space="preserve">afin d’éviter les <lb/>moindres fautes, j’ai fait faire ceux, qui ont ſervi à compoſer cette <lb/>Table, par trois perſonnes fort intelligentes, qui chacune en par-<lb/>ticulier faiſant les mêmes opérations, je n’euſſe plus qu’à voir ſi <lb/>elles ſe raportoient, de ſorte que quand elles differeroient en quel-<lb/>que choſe, je puſſe voir de quelle part l’erreur pouvoit provenir: <lb/></s> <s xml:id="echoid-s1162" xml:space="preserve">ainſi l’on peut s’aſſurer que ces calculs ont été faits avec toute la <lb/>préciſion poſſible.</s> <s xml:id="echoid-s1163" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1164" xml:space="preserve">La premiere Colomne comprend toutes les hauteurs des Murs <lb/>depuis 10 juſqu’à 100, allant en progreſſion Arithmetique dont la <lb/>difference eſt 5, c’eſt-à-dire que le premier nombre apartient à un <lb/>Mur qui auroit 10 pieds de hauteur, le ſecond à celui qui en au-<lb/>roit 15, le troiſiéme à celui qui en auroit 20, & </s> <s xml:id="echoid-s1165" xml:space="preserve">ainſi de ſuite juſ-<lb/>qu’à 100, faiſant attention que cette hauteur ne doit être compriſe <lb/>que depuis la retraite juſqu’au cordon, aux revêtemens quiſoûtien-<lb/>nent un Parapet; </s> <s xml:id="echoid-s1166" xml:space="preserve">parce que l’on fait abſtraction du petit revêtement <lb/>EC, & </s> <s xml:id="echoid-s1167" xml:space="preserve">que tous ces revêtemens ſont ſupoſés avoir pour talud <lb/>du côté du parement, la cinquiéme partie de leur hauteur, l’autre <lb/>côté étant élevé à plomb.</s> <s xml:id="echoid-s1168" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1169" xml:space="preserve">J’ai été fàché, après avoir calculé cette Table, d’avoir donné <lb/>aux Murs un talud ſi conſiderable, parce que la pratique de la plû-<lb/>part des Ingenieurs d’aujourd’hui eſt de ne donner que le 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s1170" xml:space="preserve">de la <lb/>hauteur pour talud, leur raiſon étant qu’un plus grand talud expoſe <lb/>trop le parement aux injures de l’air, ce qui cauſe des écorche-<lb/>mens au bout de quelques années, au lieu que cela n’arrive pas <pb o="44" file="0068" n="69" rhead="LA SCIENCE DES INGENIEURS,"/> quand on leur en donne moins: </s> <s xml:id="echoid-s1171" xml:space="preserve">cependant, comme cela oblige à <lb/>augmenter beaucoup l’épaiſſeur du ſommet, je doute qu’on aban-<lb/>donne abſolument l’ancienne méthode, c’eſt-à-dire celle de Mr. </s> <s xml:id="echoid-s1172" xml:space="preserve">de <lb/>Vauban qui dans ſon profil général donne pour talud la cinquiéme <lb/>partie de la hauteur; </s> <s xml:id="echoid-s1173" xml:space="preserve">& </s> <s xml:id="echoid-s1174" xml:space="preserve">c’eſt à ſon exemple que j’ai pris le même <lb/>parti, ne pouvant avoir un meilleur garent.</s> <s xml:id="echoid-s1175" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1176" xml:space="preserve">La ſeconde Colomne comprend les puiſſances équivalentes à la <lb/>pouſſée des Terres que doit ſoûtenir un revétement de Terraſſes, <lb/>de Quays, de Chauſſées, &</s> <s xml:id="echoid-s1177" xml:space="preserve">c. </s> <s xml:id="echoid-s1178" xml:space="preserve">afin que dans les occaſions où l’on <lb/>auroit beſoin de connoître cette pouſſée, on la trouve ici tout <lb/>d’un coup, ſans faire aucun calcul: </s> <s xml:id="echoid-s1179" xml:space="preserve">ainſi ſi l’on vouloit ſavoir, par <lb/>exemple, quel effort font les Terres raportées derriere un revête-<lb/>ment de 30 pieds de hauteur, ou, ce qui revient au même, quelle <lb/>ſeroit la force de la puiſſance qui agiroit au ſommet du revêtement <lb/>& </s> <s xml:id="echoid-s1180" xml:space="preserve">qui ſeroit équivalente à la pouſſée de toutes les Terres qui agiſ-<lb/>ſent derriere le revêtement depuis le haut juſqu’en bas, on cher-<lb/>chera dans la premiere Colomne le nombre 30, & </s> <s xml:id="echoid-s1181" xml:space="preserve">l’on prendra <lb/>dans la ſeconde celui qui lui répond, que l’on trouvera de 52 pieds <lb/>6 pouces 4 lignes, qu’on doit regarder comme équivalant à des <lb/>pieds provenans d’une coupe de Maçonnerie, parce qu’on a fait la <lb/>réduction de ceux de Terre, afin de pouvoir les comparer avec <lb/>les profils de Maçonnerie, ou les poids qui les expriment, comme <lb/>je l’ai aſſés expliqué dans l’article 5.</s> <s xml:id="echoid-s1182" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1183" xml:space="preserve">La troiſiéme Colomne contient, comme la ſeconde, un nom-<lb/>bre de pieds, pouces, &</s> <s xml:id="echoid-s1184" xml:space="preserve">c. </s> <s xml:id="echoid-s1185" xml:space="preserve">quarrés, qui expriment auſſi la pouſſée <lb/>des Terres, mais differemment, parce qu’on y a compris celles <lb/>du Parapet & </s> <s xml:id="echoid-s1186" xml:space="preserve">du Rempart, comme on en a fait mention dans les <lb/>Articles 35 & </s> <s xml:id="echoid-s1187" xml:space="preserve">36.</s> <s xml:id="echoid-s1188" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1189" xml:space="preserve">La quatriéme Colomne donne l’épaiſſeur que chaque revêtement <lb/>doit avoir au ſommet par raport à ſa hauteur, pour être en équili-<lb/>bre par ſon poids avec la pouſſée des Terres: </s> <s xml:id="echoid-s1190" xml:space="preserve">ainſi voulant ſavoir <lb/>l’épaiſſeur qu’il faut donner au ſommet d’un revêtement qui auroit <lb/>30 pieds de hauteur, il n’y a qu’à chercher dans la premiere Co-<lb/>lomne le nombre 30, & </s> <s xml:id="echoid-s1191" xml:space="preserve">l’on regardera dans la quatriéme le nom-<lb/>bre qui lui répond; </s> <s xml:id="echoid-s1192" xml:space="preserve">on trouvera 4 pieds 9 pouces 8 lignes pour <lb/>ce que l’on demande, ainſi des autres.</s> <s xml:id="echoid-s1193" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1194" xml:space="preserve">La cinquiéme Colomne comprend l’épaiſſeur des mêmes revê-<lb/>temens, avec cette difference qu’au lieu d’être en équilibre avec <lb/>la pouſſée des Terres, comme dans la quatriéme, les épaiſſeurs <lb/>qu’on y donne apartiennent à des revêtemens, dont la réſiſtance <lb/>ſeroit au-deſſus de l’équilibre, d’un quart de la force de la pouſſée <pb o="45" file="0069" n="70" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> des Terres: </s> <s xml:id="echoid-s1195" xml:space="preserve">c’eſt-à-dire par exemple, que ſiun Mur de 30 pieds de <lb/>hauteur eſt en équilibre avec 200 toiſes cubes de Terre en ne lui <lb/>donnant que 4 pieds 9 pouces 8 lignes au ſommet, comme dans <lb/>la quatriéme Colomne, il pourroit en ſoutenir 250 ſi on lui donnoit <lb/>l’épaiſſeur qui ſe trouve dans la cinquiéme, qui eſt de 5 pieds 11 <lb/>pouces une ligne: </s> <s xml:id="echoid-s1196" xml:space="preserve">ceci répond à ce qui a été dit dans l’Article 34. <lb/></s> <s xml:id="echoid-s1197" xml:space="preserve">on l’a calculé exprès pour ſervir à déterminer l’épaiſſeur des revê-<lb/>temens des Terraſſes, des Quays, des Chauſſées, &</s> <s xml:id="echoid-s1198" xml:space="preserve">c. </s> <s xml:id="echoid-s1199" xml:space="preserve">auſquels ne <lb/>voulant point faire des contreforts, on eſt bien aiſe de mettre leur <lb/>réſiſtance au-deſſus de la pouſſée des Terres afin d’agir en toute <lb/>ſureté; </s> <s xml:id="echoid-s1200" xml:space="preserve">au lieu que ſi l’on s’étoit attaché préciſement à l’équilibre, <lb/>il eût été à craindre que les ébranlemens cauſés par les Voitures <lb/>ne produiſiſſent des ſecouſſes qui auroient pû mettre par accident <lb/>la pouſſée des Terres au-deſſus de la réſiſtance du revêtement: </s> <s xml:id="echoid-s1201" xml:space="preserve"><lb/>malgré cette précaution, je conviens que les quatre ou cinq pre-<lb/>miers termes de cette Colomne ne donnent point aſſés d’épaiſſeur <lb/>aux Murs qui leur répondent, pour pouvoir s’en ſervir ſans con-<lb/>treforts, parce que dans la pratique on ne doit point abſolument <lb/>conſiderer la Maçonnerie comme indiſſoluble, ſur-tout quand elle <lb/>eſt nouvellement faite; </s> <s xml:id="echoid-s1202" xml:space="preserve">mais à l’exception de ces trois ou quatre <lb/>termes-là, auſquels il eſt à propos d’avoir égard, on pourra ſe ſer-<lb/>vir des autres ſans crainte.</s> <s xml:id="echoid-s1203" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1204" xml:space="preserve">Il ſemblera peut-être, ſelon ce que je viens de dire, que la qua-<lb/>triéme Colomne eſt aſſés inutile, puiſqu’on lui préferera toûjours la <lb/>cinquiéme; </s> <s xml:id="echoid-s1205" xml:space="preserve">mais, comme c’eſt elle qui donne le point d’équilibre, <lb/>pour augmenter la puiſſance d’un quart, & </s> <s xml:id="echoid-s1206" xml:space="preserve">que d’ailleurs elle nous <lb/>ſervira dans la ſuite quand nous parlerons des contreſorts, il étoit <lb/>néceſſaire de ne pas l’obmettre.</s> <s xml:id="echoid-s1207" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1208" xml:space="preserve">Quant à la ſixiéme Colomne, elle donne l’épaiſſeur du ſommet <lb/>des revêtemens des Rempars à la hauteur du cordon, dans le cas <lb/>où ces Rempars ſoûtiendroient un Parapet, & </s> <s xml:id="echoid-s1209" xml:space="preserve">ſeroient en équili-<lb/>bre par leur réſiſtance à la pouſſée des Terres qui compoſent le <lb/>Rempart & </s> <s xml:id="echoid-s1210" xml:space="preserve">le Parapet: </s> <s xml:id="echoid-s1211" xml:space="preserve">on ne parle point de combien il faudroit <lb/>augmenter l’épaiſſeur de ces revêtemens pour mettre leur réſiſtance <lb/>au-deſſus de la pouſſée des Terres, parce que cela auroit été inutile, <lb/>à cauſe qu’il convient mieux d’y ajoûter des contreforts pour les <lb/>raiſons qu’on verra dans le cinquiéme Chapitre.</s> <s xml:id="echoid-s1212" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1213" xml:space="preserve">Les termes de la quatriéme, cinquiéme, & </s> <s xml:id="echoid-s1214" xml:space="preserve">ſixiéme Colomne <lb/>ſervant à donner l’épaiſſeur du ſommet des revêtemens, on n’a pas <lb/>parlé de celles que doivent avoir leurs baſes, parce que, pour la <lb/>trouver, on n’a qu’à ajoûter à celle du ſommet la cinquiéme par- <pb o="46" file="0070" n="71" rhead="LA SCIENCE DES INGENIEURS,"/> tie de la hauteur du revêtement qu’on veut élever; </s> <s xml:id="echoid-s1215" xml:space="preserve">par exemple, <lb/>ſi l’on ajoûte 6 pieds à 4 pieds 9 pouces 8 lignes, l’on aura 8 <lb/>pieds 9 pouces 8 lignes pour l’épaiſſeur que doit avoir ſur la re-<lb/>traite un revêtement qui auroit 30 pieds de hauteur, & </s> <s xml:id="echoid-s1216" xml:space="preserve">qui ſelon <lb/>la quatriéme Colomne ſeroit en équilibre avec la pouſſée des Ter-<lb/>res: </s> <s xml:id="echoid-s1217" xml:space="preserve">il en ſera de même pour tous les autres revêtemens de la cin-<lb/>quiéme & </s> <s xml:id="echoid-s1218" xml:space="preserve">ſixiéme Colomne.</s> <s xml:id="echoid-s1219" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1220" xml:space="preserve">Comme les hauteurs des revêtemens qui ſont dans la premiere <lb/>Colomne vont en augmentant de cinq pieds, n’ayant pas voulu <lb/>ſuivre la progreſſion des nombres naturels, à cauſe que la Table <lb/>eût été d’un trop grand travail, il eſt bon de dire quelque choſe <lb/>ſur ce qu’il convient de faire quand on voudra chercher l’épaiſſeur <lb/>d’un revêtement dont la hauteur ne ſe raporteroit pas préciſement <lb/>avec quelques-uns des termes de la premiere Colomne. </s> <s xml:id="echoid-s1221" xml:space="preserve">Par exem-<lb/>ple, s’il s’agiſſoit d’un revêtement de 28 ou 29 pieds de hauteur, <lb/>on pourra prendre l’épaiſſeur qui répond à 30, quoiqu’elle ſoit un <lb/>peu plus forte qu’il ne faut. </s> <s xml:id="echoid-s1222" xml:space="preserve">Mais, ſi la hauteur étoit de 26 ou 27 <lb/>pieds, il faudra, dans le cas d’équilibre, ajoûter l’épaiſſeur qui ré-<lb/>pond à 30 pieds, avec celle qui répond à 25, & </s> <s xml:id="echoid-s1223" xml:space="preserve">prendre la moitié <lb/>de la ſomme; </s> <s xml:id="echoid-s1224" xml:space="preserve">c’eſt-à-dire 4 pieds 9 pouces 8 lignes, avec 4 pieds <lb/>7 lignes, pour avoir 8 pieds 10 pouces 3 lignes, dont la moitié <lb/>eſt 4 pieds 5 pouces 1 ligne, qui eſt ce que l’on demande: </s> <s xml:id="echoid-s1225" xml:space="preserve">on <lb/>pratiquera la même choſe pour la cinquiéme & </s> <s xml:id="echoid-s1226" xml:space="preserve">la ſixiéme Colomne.</s> <s xml:id="echoid-s1227" xml:space="preserve"/> </p> <figure> <image file="0070-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0070-01"/> </figure> <pb file="0071" n="72"/> <pb file="0071a" n="73"/> <figure> <image file="0071a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0071a-01"/> </figure> <pb file="0072" n="74"/> <pb o="47" file="0073" n="75" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div94" type="section" level="1" n="61"> <head xml:id="echoid-head74" xml:space="preserve">TABLE</head> <head xml:id="echoid-head75" style="it" xml:space="preserve">Pour régler l’Epaiſſeur qu’il faut donner aux Revêtemens de <lb/>Maçonnerie qui ſoûtiennent des Terraſſes ou Rempars.</head> <note position="right" xml:space="preserve">Hauteur \\ des re- \\ vête- \\ mens. ### Valeur des puiſ- \\ ſances qui ſont \\ équivalentes à la \\ pouſſée des Ter- \\ res qui n’ont \\ point de Para- \\ pet. ### Valeur des puiſ- \\ ſanees qui ſont \\ équivalentes à la \\ pouſſee des Ter- \\ res du Rémpart \\ & du Parapet des \\ Ouvrages de For- \\ tification. ### Epaiſſeur du ſom- \\ met des revête- \\ mens qui ſont \\ en équilibre avec \\ la pouſſée des \\ Terres lorſqu’il \\ n’y a pas de Pa- \\ rapet. ### Epaiſleur du ſom- \\ met des revête- \\ mens dont la ré- \\ ſiſtance eſt au- \\ deſſus de l’équi- \\ libre d’un quart \\ de la pouſſée. ### Epaiſſeur des re- \\ vêtemens qui \\ ſont en équili- \\ bre par leur ré- \\ ſiſtance avec des \\ Rempars qui \\ ſoûtiennent un \\ Parapet. <lb/>pieds. # pieds. # pou. # lig. # pieds. # pou. # lig. # pieds. # pou. # lig. # pieds. # pou. # lig. # pieds. # pou. # lig. <lb/>10. # 6. # 5. # 0. # 15. # 7. # 0. # 1. # 9. # 1. # 1. # 11. # 6. # 3. # 8. # 4. <lb/>15. # 13. # 9. # 4. # 27. # 1. # 4. # 2. # 6. # 2. # 2. # 9. # 11. # 4. # 6. # 8. <lb/>20. # 23. # 11. # 0. # 41. # 5. # 0. # 3. # 3. # 5. # 3. # 8. # 3. # 5. # 4. # 6. <lb/>25. # 36. # 6. # 0. # 57. # 6. # 0. # 4. # 0. # 7. # 4. # 6. # 7. # 6. # 1. # 2. <lb/>30. # 52. # 6. # 4. # 74. # 4. # 0. # 4. # 9. # 8. # 5. # 4. # 9. # 6. # 9. # 0. <lb/>35. # 71. # 0. # 0. # 95. # 3. # 4. # 5. # 6. # 11. # 6. # 3. # 1. # 7. # 4. # 8. <lb/>40. # 92. # 3. # 0. # 117. # 8. # 0. # 6. # 3. # 10. # 7. # 1. # 6. # 8. # 1. # 2. <lb/>45. # 116. # 3. # 0. # 142. # 7. # 0. # 7. # 1. # 3. # 7. # 11. # 10. # 8. # 7. # 11. <lb/>50. # 143. # 1. # 0. # 170. # 1. # 0. # 7. # 10. # 5. # 8. # 10. # 0. # 9. # 3. # 00. <lb/>55. # 172. # 8. # 0. # 200. # 3. # 0. # 8. # 7. # 6. # 9. # 8. # 4. # 9. # 11. # 10. <lb/>60. # 205. # 0. # 4. # 233. # 1. # 0. # 9. # 4. # 9. # 10. # 6. # 8. # 10. # 9. # 1. <lb/>65. # 240. # 2. # 0. # 271. # 10. # 0. # 10. # 2. # 0. # 11. # 5. # 1. # 11. # 4. # 3. <lb/>70. # 278. # 1. # 0. # 306. # 9. # 0. # 10. # 11. # 0. # 12. # 3. # 4. # 12. # 0. # 8. <lb/>75. # 318. # 9. # 0. # 347. # 10. # 0. # 11. # 8. # 3. # 13. # 1. # 8. # 12. # 9. # 1. <lb/>80. # 362. # 3. # 0. # 391. # 7. # 6. # 12. # 5. # 4. # 14. # 0. # 0. # 13. # 5. # 6. <lb/>85. # 408. # 6. # 0. # 438. # 6. # 0. # 13. # 2. # 7. # 14. # 10. # 3. # 14. # 2. # 1. <lb/>90. # 457. # 6. # 0. # 487. # 3. # 8. # 13. # 11. # 9. # 15. # 8. # 6. # 14. # 10. # 9. <lb/>95. # 526. # 10. # 6. # 556. # 10. # 6. # 14. # 8. # 10. # 16. # 6. # 11. # 15. # 7. # 5. <lb/>100. # 563. # 11. # 0. # 594. # 10. # 0. # 15. # 6. # 1. # 17. # 5. # 3. # 16. # 4. # 2. <lb/></note> <pb o="48" file="0074" n="76" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div95" type="section" level="1" n="62"> <head xml:id="echoid-head76" xml:space="preserve">PROPOSITION TROISIE’ME.</head> <head xml:id="echoid-head77" xml:space="preserve"> <emph style="sc">Proble’me</emph> </head> <p style="it"> <s xml:id="echoid-s1228" xml:space="preserve">38. </s> <s xml:id="echoid-s1229" xml:space="preserve">Voulant augmenter l’épaiſſeur d’un revêtement qui <lb/>ſeroit en équilibre avec la pouſſée des Terres, on demande de <lb/>combien la réſiſtance de ce revêtement deviendra plus forte <lb/>qu’elle n’étoit par rapport à l’augmentation qu’on veut faire.</s> <s xml:id="echoid-s1230" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1231" xml:space="preserve">Pour réſoudre ce Probléme, nous ſupoſerons que a, exprime l’é-<lb/>paiſſeur au ſommet d’un revêtement quelconque, quand la réſiſtance <lb/>du Mur eſt égale à la pouſſée des Terres, & </s> <s xml:id="echoid-s1232" xml:space="preserve">que m, exprime la nouvel-<lb/>le épaiſſeur compoſée de la premiere & </s> <s xml:id="echoid-s1233" xml:space="preserve">de l’augmentation propo-<lb/>ſée; </s> <s xml:id="echoid-s1234" xml:space="preserve">cela poſé, ſi dans le premier membre de l’équation yy + 2dy <lb/>+ {2dd/3} = 2bf, (où nous avons vû Art. </s> <s xml:id="echoid-s1235" xml:space="preserve">22. </s> <s xml:id="echoid-s1236" xml:space="preserve">que le poids étoit en <lb/>équilibre avec la puiſſance) l’on met a, au lieu de y, l’on aura <lb/>aa + 2da + {2dd/3} pour la réſiſtance dont le revêtement eſt capable <lb/>étant en équilibre avec la pouſſée des Terres; </s> <s xml:id="echoid-s1237" xml:space="preserve">& </s> <s xml:id="echoid-s1238" xml:space="preserve">mettant encore <lb/>m, à la place de y, dans la même équation, l’on aura mm + 2dm <lb/>+ {2dd/3} pour la réſiſtance du revêtement après avoir augmenté <lb/>ſon épaiſſeur, par conſéquent le rapport que nous cherchons ſera <lb/>égal à {aa + 2da + {2dd/3}/mm + 2dm + {2dd/3}} qu’on connoîtra en mettant des nombres <lb/>à la place des Lettres.</s> <s xml:id="echoid-s1239" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div96" type="section" level="1" n="63"> <head xml:id="echoid-head78" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s1240" xml:space="preserve">Remarqués que le numerateur de la fraction précedente n’eſt au-<lb/>tre choſe que le quarré de a + d, c’eſt-à-dire le quarré de l’épaiſ-<lb/>ſeur de la baſe, du revêtement moins le tiers du quarré de la ligne <lb/>de talud, & </s> <s xml:id="echoid-s1241" xml:space="preserve">que le dénominateur eſt auſſi égal au quarré de la <lb/>baſe du revêtement, dont on a augmenté l’épaiſſeur, moins le tiers <lb/>du quarré de la même ligne de talud. </s> <s xml:id="echoid-s1242" xml:space="preserve">Or s’il s’agit d’un revêtement <lb/>de 30 pieds de hauteur, qui ſoûtienne un Rampart avec un Parapet, <lb/>ſelon la ſixiéme Colomne de la Table, l’épaiſſeur de ce revêtement <pb o="49" file="0075" n="77" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> au ſommet dans l’état d’équilibre, ſera 6 pieds 9 pouces, à quoi <lb/>ajoûtant la ligne de talud qui eſt 6 pieds, l’épaiſſeur de la baſe ſera <lb/>12 pieds 9 pouces, dont le quarré eſt 162 pieds 6 pouces 9 lignes <lb/>duquel retranchant 12 qui eſt le tiers du quarré de la ligne de ta-<lb/>lud, il reſtera 150 pieds pour la valeur de aa + 2da + {2dd/3} en né-<lb/>gligeant les 6 pouces 9 lignes qui ne feroient qu’embarraſſer. </s> <s xml:id="echoid-s1243" xml:space="preserve">Mais <lb/>ſi l’on veut augmenter de 15 pouces l’épaiſſeur en queſtion, la <lb/>baſe ſera de 14 pieds, dont le quarré eſt 196, d’où retranchant en-<lb/>core 12, il reſtera 184 pour mm + 2dm + {2dd/3}, ainſi l’on aura <lb/>{150/184} qui étant réduit donne à peu-près {5/6} ce qui fait voir que <lb/>les 15 pouces dont on a augmenté l’épaiſſeur du revêtement le <lb/>rendent plus fort de la cinquiéme partie de la force qu’il lui auroit <lb/>fallu pour être en équilibre avec la pouſſée des Terres.</s> <s xml:id="echoid-s1244" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div97" type="section" level="1" n="64"> <head xml:id="echoid-head79" xml:space="preserve">PROPOSITION QUATRIE’ME.</head> <head xml:id="echoid-head80" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s1245" xml:space="preserve">39. </s> <s xml:id="echoid-s1246" xml:space="preserve">Connoiſſant la hauteur & </s> <s xml:id="echoid-s1247" xml:space="preserve">les épaiſſeurs du ſommet & </s> <s xml:id="echoid-s1248" xml:space="preserve"><lb/>de la baſe d’un Mur qui ne ſoûtient aucune pouſſée, trouver <lb/>quelle eſt la puiſſance avec laquelle il pourroit être en <lb/>équilibre.</s> <s xml:id="echoid-s1249" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1250" xml:space="preserve">Si un Mur AD, eſt élevé à plomb des deux côtés; </s> <s xml:id="echoid-s1251" xml:space="preserve">qu’on nom-<lb/> <anchor type="note" xlink:label="note-0075-01a" xlink:href="note-0075-01"/> me c, ſa hauteur AC; </s> <s xml:id="echoid-s1252" xml:space="preserve">a, l’épaiſſeur AB, ou CD; </s> <s xml:id="echoid-s1253" xml:space="preserve">& </s> <s xml:id="echoid-s1254" xml:space="preserve">x, une puiſ-<lb/> <anchor type="note" xlink:label="note-0075-02a" xlink:href="note-0075-02"/> ſance P, qui tireroit de A, en F, le poids M, ſera ac; </s> <s xml:id="echoid-s1255" xml:space="preserve">il eſt conſ-<lb/>tant que le point d’apui étant en C, l’on aura x, ac, : </s> <s xml:id="echoid-s1256" xml:space="preserve">: </s> <s xml:id="echoid-s1257" xml:space="preserve">{a/2}c, dont <lb/>le produit des extrêmes & </s> <s xml:id="echoid-s1258" xml:space="preserve">celui des moyens donnent, après la ré-<lb/>duction, {aa/2} = x.</s> <s xml:id="echoid-s1259" xml:space="preserve"/> </p> <div xml:id="echoid-div97" type="float" level="2" n="1"> <note position="right" xlink:label="note-0075-01" xlink:href="note-0075-01a" xml:space="preserve"><emph style="sc">Planch</emph>, <lb/>3.</note> <note position="right" xlink:label="note-0075-02" xlink:href="note-0075-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 1.</note> </div> <p> <s xml:id="echoid-s1260" xml:space="preserve">Mais, ſi le Mur étoit comme le Profil CA, c’eſt-à-dire qu’il fût <lb/> <anchor type="note" xlink:label="note-0075-03a" xlink:href="note-0075-03"/> élevé à plomb d’un côté & </s> <s xml:id="echoid-s1261" xml:space="preserve">qu’il eût un talud de l’autre, il eſt cer-<lb/>tain que la puiſſance que l’on cherche tirant de E, en Q, feroit un <lb/>effet tout different que dans la figure précédente; </s> <s xml:id="echoid-s1262" xml:space="preserve">or pour trouver <lb/>la valeur de cette puiſſance, nous nommerons DF, a; </s> <s xml:id="echoid-s1263" xml:space="preserve">FA, d; </s> <s xml:id="echoid-s1264" xml:space="preserve">la <lb/>hauteur EF, c; </s> <s xml:id="echoid-s1265" xml:space="preserve">& </s> <s xml:id="echoid-s1266" xml:space="preserve">la puiſſance Q, y; </s> <s xml:id="echoid-s1267" xml:space="preserve">cela poſé, ayant réüni le <lb/>poids O, au poids N, & </s> <s xml:id="echoid-s1268" xml:space="preserve">multiplié leur ſomme par le bras G A, <lb/>l’on aura un produit égal à celui de la puiſſance Q, (y) par la per- <pb o="50" file="0076" n="78" rhead="LA SCIENCE DES INGENIEURS,"/> pendiculaire AB, & </s> <s xml:id="echoid-s1269" xml:space="preserve">ſi de chacun de ces produits l’on efface <lb/>la lettre c, il viendra {aa/2} + ad + {dd/3} = y, qui fait voir que <lb/>la puiſſance Q, eſt égale à la moitié du quarré de l’épaiſſeur CE, <lb/>ou DF, plus autiers du quarré de la ligne de talud FA, plus enfin <lb/>à un rectangle compris ſous DF, & </s> <s xml:id="echoid-s1270" xml:space="preserve">FA.</s> <s xml:id="echoid-s1271" xml:space="preserve"/> </p> <div xml:id="echoid-div98" type="float" level="2" n="2"> <note position="right" xlink:label="note-0075-03" xlink:href="note-0075-03a" xml:space="preserve"><emph style="sc">Fig</emph>. 2</note> </div> </div> <div xml:id="echoid-div100" type="section" level="1" n="65"> <head xml:id="echoid-head81" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s1272" xml:space="preserve">On peut faire uſage de cette Propoſition, pour voir ſi des Murs, <lb/>qui ne ſoûtiennent rien, peuvent ſervir de revêtement à des Rem-<lb/>pars qu’on voudroit élever derriere, puiſque cherchant dans la <lb/>Table à quoi peut aller la pouſſée des Terres, on s’appercevra ſi <lb/>ces Murs ont aſſés de force, car ſi le mur qui eſt élevé à plomb des <lb/>deux côtés a par exemple ſix pieds d’épaiſſeur, la moitié de ſon <lb/>quarré ſera 18, ainſi il ne pourra tout au plus ſoûtenir qu’une puiſ-<lb/>ſance équivalante à 18 pieds quarrés.</s> <s xml:id="echoid-s1273" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1274" xml:space="preserve">De même, dans le ſecond Profil, ſupoſant l’épaiſſeur D F, de 4 <lb/>pieds, la ligne de talud F A, de 5, ſuivant ce qu’enſeigne l’équa-<lb/>tion {aa/2} + ad + {dd/3} = y, l’on trouvera que la puiſſance Q, eſt <lb/>de 36 pieds 4 pouces, & </s> <s xml:id="echoid-s1275" xml:space="preserve">que par conſéquent la pouſſée des Terres <lb/>qu’on voudroit lui faire ſoûtenir ne doit point paſſer cette quan-<lb/>tité.</s> <s xml:id="echoid-s1276" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div101" type="section" level="1" n="66"> <head xml:id="echoid-head82" xml:space="preserve">CHAPITRE CINQUIE’ME.</head> <head xml:id="echoid-head83" style="it" xml:space="preserve">De la conſidération des Murs qui ont des Contreforts.</head> <p> <s xml:id="echoid-s1277" xml:space="preserve">TOut le monde ſait que les contreforts qu’on éleve avec les <lb/>murs contribuent beaucoup à les fortifier contre la pouſſée des <lb/>Terres ou des Voûtes quand ils en ſoûtiennent, mais il ne paroît <lb/>pas qu’on ſe ſoit apliqué à éxaminer de combien ils pouvoient ren-<lb/>dre ces murs capables d’une plus ou moins grande réſiſtance, ſe-<lb/>lon la longueur, l’épaiſſeur, la diſtance, & </s> <s xml:id="echoid-s1278" xml:space="preserve">même la figure qu’on <lb/>donneroit aux contreforts. </s> <s xml:id="echoid-s1279" xml:space="preserve">Ce ſujet eſt pourtant digne d’attention, <lb/>ſur-tout quand il s’agit de certains Ouvrages qui doivent plûtôt ti-<lb/>rer leur ſolidité des régles de l’art, que de l’abondance des maté-<lb/>riaux, puiſque ſi l’on connoiſſoit bien le mécaniſme qui apartient à <pb o="51" file="0077" n="79" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> ce ſujet, on éleveroit des Edifices qui ſeroient encore plus hardis <lb/>que la plûpart de ceux qui font tant d’honneur aux ſiécles paſſés; <lb/></s> <s xml:id="echoid-s1280" xml:space="preserve">on travailleroit avec ſûreté, & </s> <s xml:id="echoid-s1281" xml:space="preserve">l’on n’apercevroit pas une certaine <lb/>timidité qui eſtaſſés ordinaire aux Ouvrages des Modernes: </s> <s xml:id="echoid-s1282" xml:space="preserve">les an-<lb/>ciens Architectes paroiſſent en ceci plus éclairés; </s> <s xml:id="echoid-s1283" xml:space="preserve">s’ils n’avoient <lb/>pas des régles certaines & </s> <s xml:id="echoid-s1284" xml:space="preserve">démontrées comme celles qu’on deman-<lb/>de, ils agiſſoient au moins avec unjugement qui en aprochoit beau-<lb/>coup: </s> <s xml:id="echoid-s1285" xml:space="preserve">les beaux monumens qu’ils nous ont laiſſés en font foi, leurs <lb/>Egliſes ſont d’une légereté admirable, il ſemble qu’ils ont uſé de <lb/>quelques moyens extraordinaires, qu’on a perdu avec eux; </s> <s xml:id="echoid-s1286" xml:space="preserve">cepen-<lb/>dant, ſi l’on y prend garde de près, l’on verra que tout ce qui en <lb/>fait le merveilleux, n’eſt autre choſe que la bonne liaiſon des ma-<lb/>teriaux, la ſituation & </s> <s xml:id="echoid-s1287" xml:space="preserve">l’étenduë des contreforts dont ils ſe ſont <lb/>toûjours ſervi heureuſement, & </s> <s xml:id="echoid-s1288" xml:space="preserve">comme peu de gens s’arrêtent à <lb/>cette derniere particularité faute d’en connoître tout le mérite, <lb/>ils ſont ravis d’un étonnement qu’ils ne ſavent à quoi attribuer: </s> <s xml:id="echoid-s1289" xml:space="preserve">les <lb/>Egliſes que l’on a bâti dans ces derniers tems, & </s> <s xml:id="echoid-s1290" xml:space="preserve">entr’autres quel-<lb/>ques-unes de Paris, ſont bien éloignées d’intriguer perſonne: </s> <s xml:id="echoid-s1291" xml:space="preserve">ſi el-<lb/>les cauſent quelque ſurpriſe, c’eſt de les voir ſi materielles, qu’elles <lb/>ſemblent avoir épuiſé toutes les Carrieres du Pays. </s> <s xml:id="echoid-s1292" xml:space="preserve">Eſt-il poſſi-<lb/>ble que l’intervalle de quelques ſiécles rende les hommes ſi opoſés <lb/>ſur une même choſe? </s> <s xml:id="echoid-s1293" xml:space="preserve">Ne conviendra-t’-on jamais, que dans tout <lb/>ce que l’on fait qui eſt ſuſceptible de plus & </s> <s xml:id="echoid-s1294" xml:space="preserve">de moins, il y a un <lb/>certain point d’où dépend la conſtruction la plus parfaite qu’il eſt <lb/>poſſible d’atteindre, & </s> <s xml:id="echoid-s1295" xml:space="preserve">que c’eſt à ce point-là qu’il faut uniquement <lb/>s’apliquer, afin d’y demeurer fixe quand on l’aura une fois trouvé? </s> <s xml:id="echoid-s1296" xml:space="preserve"><lb/>De pareilles recherches ſeroient d’un grand avantage pour la per-<lb/>fection de l’Architecture; </s> <s xml:id="echoid-s1297" xml:space="preserve">on ne peut trop engager ceux qui la <lb/>cultivent d’y travailler, & </s> <s xml:id="echoid-s1298" xml:space="preserve">comme les contreforts y doivent avoir <lb/>beaucoup de part, nous allons faire enſorte dans ce Chapitre d’en <lb/>bien déveloper toute la Théorie; </s> <s xml:id="echoid-s1299" xml:space="preserve">mais, avant cela, il eſt à propos <lb/>que j’avertiſſe qu’il faut ſupoſer que les contreforts, dont nous par-<lb/>lerons, ont été conſtruits dans le même tems que les murs qu’ils <lb/>ſoûtiennent, & </s> <s xml:id="echoid-s1300" xml:space="preserve">que la liaiſon eſt ſi parfaite, que de part & </s> <s xml:id="echoid-s1301" xml:space="preserve">d’autre <lb/>elle ne fait plus qu’un ſeul corps.</s> <s xml:id="echoid-s1302" xml:space="preserve"/> </p> <pb o="52" file="0078" n="80" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div102" type="section" level="1" n="67"> <head xml:id="echoid-head84" xml:space="preserve">PROPOSITION PREMIERE. <lb/><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s1303" xml:space="preserve">40. </s> <s xml:id="echoid-s1304" xml:space="preserve">Ayant le Profil ABCD, d’un mur élevé à plomb des <lb/>deux côtés & </s> <s xml:id="echoid-s1305" xml:space="preserve">ſoutenu par des contreforts repréſentés par le rec-<lb/>tangle AEFC, on demande ſi une puiſſance Q, agiſſoit de A, <lb/>en B, pour renverſer ce mur du côté du parement, ou une autre <lb/>P, de A, en E, pour le renverſer du côté des contreforts, quel <lb/>eſt le raport de la réſiſtance du mur dans ces deux cas, ou ce qui <lb/>eſt la même choſe, le raport de la puiſſance Q, à la puiſſance P, <lb/>ſupoſant qu’elles agiſſent chacune en particulier.</s> <s xml:id="echoid-s1306" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1307" xml:space="preserve">Conſiderés la Figure 5. </s> <s xml:id="echoid-s1308" xml:space="preserve">qui repréſente le Plan de la Maçonne-<lb/> <anchor type="note" xlink:label="note-0078-01a" xlink:href="note-0078-01"/> rie du Profil qui eſt au-deſſus, dont les contreforts ſont rectan-<lb/>gles & </s> <s xml:id="echoid-s1309" xml:space="preserve">égaux dans ce Plan, l’on ſupoſe que l’épaiſſeur LI, des <lb/>contreforts eſt égale à l’épaiſſeur C D, de la muraille; </s> <s xml:id="echoid-s1310" xml:space="preserve">que leur lon-<lb/>gueur FC, eſt double de leur épaiſſeur, & </s> <s xml:id="echoid-s1311" xml:space="preserve">que leur diſtance CL, <lb/>ou IK, eſt double de la longueur FC, ainſi nommant l’épaiſſeur <lb/>CD, ou LI, a; </s> <s xml:id="echoid-s1312" xml:space="preserve">FC, ſera 2a, & </s> <s xml:id="echoid-s1313" xml:space="preserve">CL, ou IK, ſera 4a; </s> <s xml:id="echoid-s1314" xml:space="preserve">quant à la <lb/>hauteur AC, de la muraille & </s> <s xml:id="echoid-s1315" xml:space="preserve">des contreforts, nous la nomme-<lb/>rons b, cela poſé, ab, ſera la valeur du rectangle AD, ramaſſé <lb/>dans le poids N, qui eſt ſuſpendu dans le milieu de la ligne CD, <lb/>& </s> <s xml:id="echoid-s1316" xml:space="preserve">2ab, ſera la valeur du rectangle EC: </s> <s xml:id="echoid-s1317" xml:space="preserve">or comme cette muraille <lb/>n’a point de longueur déterminée, nous n’y aurons point égard; <lb/></s> <s xml:id="echoid-s1318" xml:space="preserve">cependant les contreforts étant à une certaine diſtance, & </s> <s xml:id="echoid-s1319" xml:space="preserve">ne for-<lb/>mant point de maſſif continu, comme la muraille fait dans ſa lon-<lb/>gueur, on ne peut pas dire que 2ab, expriment la valeur des contre-<lb/>forts, puiſque pour cela il faudroit qu’il n’y eût point d’intervalle <lb/>entr’eux; </s> <s xml:id="echoid-s1320" xml:space="preserve">il faut donc réduire la valeur des contreforts, de façon <lb/>qu’on puiſſe la conſiderer comme ſi elle régnoit ſur toute la lon-<lb/>gueur du mur: </s> <s xml:id="echoid-s1321" xml:space="preserve">pour cela l’on n’a qu’à diviſer 2ab, par 5, & </s> <s xml:id="echoid-s1322" xml:space="preserve">l’on aura <lb/>{2ab/5} égal à l’expreſſion du poids M, qu’on doit regarder comme <lb/>équivalant à tous les contreforts réünis enſemble dans un des points <lb/>de la ligne G M, tirée du centre de gravité.</s> <s xml:id="echoid-s1323" xml:space="preserve"/> </p> <div xml:id="echoid-div102" type="float" level="2" n="1"> <note position="left" xlink:label="note-0078-01" xlink:href="note-0078-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4. <lb/>& 5.</note> </div> <p> <s xml:id="echoid-s1324" xml:space="preserve">Preſentement, il faut réünir le poids M, au poids N, enſorte <lb/>qu’il péſe autant en H, qu’il péſe en G, par raport au point d’apui <pb o="53" file="0079" n="81" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> D, ainſi je multiplie la valeur du poids M, par ſon bras de lévier <lb/>GD, (2a) pour avoir {4aab/5}, que je diviſe par le bras HD, <lb/>({a/2}) le quotient eſt {8ab/5}, qui étant ajoûté avec le poids N, <lb/>(ab) donne {13ab/5} pour la ſomme des poids M, & </s> <s xml:id="echoid-s1325" xml:space="preserve">N, réünis ſi <lb/>l’on veut dans le ſeul poids O: </s> <s xml:id="echoid-s1326" xml:space="preserve">maintenant ſi l’on nomme x, la puiſ-<lb/>ſance Q, & </s> <s xml:id="echoid-s1327" xml:space="preserve">qu’on conſidere les lignes HD, & </s> <s xml:id="echoid-s1328" xml:space="preserve">BD, comme fai-<lb/>ſant un lévier recourbé dont le point d’apui eſt en D, l’on aura <lb/>BD, (b) HD, ({a/2}) : </s> <s xml:id="echoid-s1329" xml:space="preserve">: </s> <s xml:id="echoid-s1330" xml:space="preserve">O, ({13ab/5}) x, qui donne cette équa-<lb/>tion bx = {13aab/10}, ou bien x = {13aa/10} qui fait voir que la puiſſance <lb/>Q, eſt {13aa/10}.</s> <s xml:id="echoid-s1331" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1332" xml:space="preserve">Si au lieu de ſupoſer le point d’apui en D, on le ſupoſe en F, <lb/>l’on aura le lévier recourbé EFH, à l’extrêmité d’un des bras du-<lb/>quel eſt encore le poids O, qui exprime toûjours la muraille & </s> <s xml:id="echoid-s1333" xml:space="preserve">les <lb/>contreforts, & </s> <s xml:id="echoid-s1334" xml:space="preserve">la puiſſance P, à l’autre bras, laquelle étant nom-<lb/>mée y, donnera dans l’état d’équilibre EF, (b) FH, ({5a/2}) :</s> <s xml:id="echoid-s1335" xml:space="preserve">: <lb/>{29ab/25}, y. </s> <s xml:id="echoid-s1336" xml:space="preserve">D’où l’on tire y = {29aa/10}, par conſéquent Q, (x) P, <lb/>(y;) </s> <s xml:id="echoid-s1337" xml:space="preserve">{13aa/10}, {29aa/10} ou comme treize eſt à vingt-neuf.</s> <s xml:id="echoid-s1338" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div104" type="section" level="1" n="68"> <head xml:id="echoid-head85" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s1339" xml:space="preserve">41. </s> <s xml:id="echoid-s1340" xml:space="preserve">Cette propoſition montre clairement qu’un mur qui a des <lb/>contreforts réſiſte beaucoup plus à l’effort d’une puiſſance quand <lb/>elle agit dans un ſens opoſé aux contreforts, que lorſqu’elle pouſſe <lb/>du côté des contreforts mêmes, à cauſe de la difference des bras <lb/>de léviers qui répondent à la baſe.</s> <s xml:id="echoid-s1341" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div105" type="section" level="1" n="69"> <head xml:id="echoid-head86" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s1342" xml:space="preserve">42. </s> <s xml:id="echoid-s1343" xml:space="preserve">L’on remarquera encore, que ſi dans les revêtemens de For-<lb/>tifications & </s> <s xml:id="echoid-s1344" xml:space="preserve">de Terraſſes, l’on n’avoit égard qu’à la pouſſée des Ter-<lb/>res, il vaudroit beaucoup mieux faire les contreforts en dehors <lb/>qu’en dedans: </s> <s xml:id="echoid-s1345" xml:space="preserve">cependant cela ne ſe pratique point ainſi, pour ne pas <lb/>choquer la vüë, & </s> <s xml:id="echoid-s1346" xml:space="preserve">pour d’autres raiſons qui ſe font aſſés ſentir; </s> <s xml:id="echoid-s1347" xml:space="preserve">mais <pb o="54" file="0080" n="82" rhead="LA SCIENCE DES INGENIEURS,"/> quand il s’agit de ſoûtenir les piés-droits d’une Voûte, c’eſt alors <lb/>qu’il faut abſolument les placer en dehors, afin qu’ils ſoient direc-<lb/>tement opoſés à la pouſſée.</s> <s xml:id="echoid-s1348" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div106" type="section" level="1" n="70"> <head xml:id="echoid-head87" style="it" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s1349" xml:space="preserve">43. </s> <s xml:id="echoid-s1350" xml:space="preserve">Pour faire voir à quel point un mur, qui ſoûtient quelque <lb/>pouſſée, eſt capable de réſiſter davantage lorſqu’il y a des contre-<lb/>forts que quand il n’y en a point, quoique la même quantité de <lb/>Maçonnerie ſubſiſte de part & </s> <s xml:id="echoid-s1351" xml:space="preserve">d’autre, augmentons par plaiſir l’é-<lb/>paiſſeur CD, de la muraille de toute la maçonnerie qui eſt employée <lb/> <anchor type="note" xlink:label="note-0080-01a" xlink:href="note-0080-01"/> dans les contreforts: </s> <s xml:id="echoid-s1352" xml:space="preserve">pour cela je diviſe la longueur FC, (2a) par <lb/>5, pour avoir {2a/5} qui ſera l’épaiſſeur RC, réduite, qui étant ajoû-<lb/>tée avec CD, donnera {7a/5} pour toute l’épaiſſeur RD, ou PX, du <lb/> <anchor type="note" xlink:label="note-0080-02a" xlink:href="note-0080-02"/> nouveau Profil rX, qui étant multipliée par la hauteur rP, (b) <lb/>donne {7ab/5} pour la valeur du rectangle rX, réüni au poids T, qui <lb/>eſt ſuſpendu dans le milieu V, de la ligne PX: </s> <s xml:id="echoid-s1353" xml:space="preserve">or ſupoſant le point <lb/>d’apui en X, & </s> <s xml:id="echoid-s1354" xml:space="preserve">une puiſſance S, qui tire de R, en S, nommant <lb/>cette puiſſance z, l’on aura dans le cas d’équilibre RX, (b) XV, <lb/>({7a/10}):</s> <s xml:id="echoid-s1355" xml:space="preserve">:T, ({7ab/5}) z, qui donne {49aa/50} = z, & </s> <s xml:id="echoid-s1356" xml:space="preserve">comme 49 ne <lb/>differe de 50 que d’une unité, nous ſupoſerons aa = z.</s> <s xml:id="echoid-s1357" xml:space="preserve"/> </p> <div xml:id="echoid-div106" type="float" level="2" n="1"> <note position="left" xlink:label="note-0080-01" xlink:href="note-0080-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4. <lb/>& 5.</note> <note position="left" xlink:label="note-0080-02" xlink:href="note-0080-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s1358" xml:space="preserve">Preſentement, pour comparer la puiſſance Q, ({13aa/10}) à la puiſ-<lb/>ſance S, on donnera à la ſeconde le même dénominateur qu’à la <lb/>prémiere, & </s> <s xml:id="echoid-s1359" xml:space="preserve">pour lors l’on aura Q, S, :</s> <s xml:id="echoid-s1360" xml:space="preserve">: {13aa/10}, {10aa/10}, qui é-<lb/>tant réduite, donne Q, S, :</s> <s xml:id="echoid-s1361" xml:space="preserve">: 13, 10. </s> <s xml:id="echoid-s1362" xml:space="preserve">L’on peut donc conclure <lb/>de tout ceci, que plus les contreforts ſeront longs, & </s> <s xml:id="echoid-s1363" xml:space="preserve">plus le bras <lb/>de lévier ſera à l’avantage de la puiſſance réſiſtante, c’eſt pour-<lb/>quoi dans les occaſions où l’on peut ſe diſpenſer de donner une <lb/>grande épaiſſeur aux contreforts, il vaut mieux étendre ſur leur <lb/>longueur, que ſur leur épaiſſeur, la maçonnerie qu’on leur deſtine, <lb/>afin que l’ouvrage en ſoit encore plus inébranlable.</s> <s xml:id="echoid-s1364" xml:space="preserve"/> </p> <pb o="55" file="0081" n="83" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div108" type="section" level="1" n="71"> <head xml:id="echoid-head88" xml:space="preserve">PROPOSITION SECONDE. <lb/><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s1365" xml:space="preserve"><emph style="bf">44.</emph> Ayant un revêtement de Terraſſe ABCD, & </s> <s xml:id="echoid-s1366" xml:space="preserve">une puiſ-<lb/> <anchor type="note" xlink:label="note-0081-01a" xlink:href="note-0081-01"/> ſance P, dont la force eſt ſupoſée beaucoup au-de ſſus de la ré-<lb/>ſiſtance, dont le revêtement eſt capable par ſon poids, on deman-<lb/>de de quelle longueur il faudra faire les contreforts qu’on <lb/>voudroit y ajoûter afin que le tout ſoit en équilibre avec cet-<lb/>te puiſſance.</s> <s xml:id="echoid-s1367" xml:space="preserve"/> </p> <div xml:id="echoid-div108" type="float" level="2" n="1"> <note position="right" xlink:label="note-0081-01" xlink:href="note-0081-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 6. <lb/>& 7.</note> </div> <p> <s xml:id="echoid-s1368" xml:space="preserve">Pour bien entendre ce Probleme il faut être prévenu que la <lb/>hauteur CE, du revêtement eſt ſupoſée de 30 pieds, & </s> <s xml:id="echoid-s1369" xml:space="preserve">qu’ainſi <lb/>ſelon la regle générale, la ligne de talud ED, doit être de 6 pieds. <lb/></s> <s xml:id="echoid-s1370" xml:space="preserve">Or ſi ce revêtement avoit des Terres à ſoûtenir, on verra dans la <lb/>Table que la puiſſance équivalente à leur pouſſée, c’eſt-à-dire la <lb/>puiſſance P, eſt de 52 pieds 6. </s> <s xml:id="echoid-s1371" xml:space="preserve">pouces 4 lignes, & </s> <s xml:id="echoid-s1372" xml:space="preserve">que pour met-<lb/>tre le revêtement en équilibre avec cette puiſſance, il faudroit <lb/>donner 4 pieds 9 pouces 8 lignes à l’épaiſſeur BC, du ſommet, <lb/>par conſéquent ſi l’on diminuoit cette épaiſſeur de quelque choſe; </s> <s xml:id="echoid-s1373" xml:space="preserve"><lb/>c’eſt-à-dire, par exemple, que ſi au lieu de lui donner 4 pieds 9 <lb/>pouces 8 lignes, on ne lui donnoit que 3 pieds, la puiſſance étant <lb/>toûjours ſupoſée la même, il eſt certain que le revêtement ne ſeroit <lb/>plus en équilibre, parce que le bras de lévier ID, ſera racourci, <lb/>& </s> <s xml:id="echoid-s1374" xml:space="preserve">le poids M, diminué, ce qui mettroit la puiſſance beacoup au-<lb/>deſſus de la réſiſtance du revêtement: </s> <s xml:id="echoid-s1375" xml:space="preserve">cependant comme on veut <lb/>maintenir l’un & </s> <s xml:id="echoid-s1376" xml:space="preserve">l’autre en équilibre, on prend le parti de faire des <lb/>contreforts, & </s> <s xml:id="echoid-s1377" xml:space="preserve">la queſtion ſe réduit à ſavoir quelle longueur il <lb/>faudra leur donner par raport à leur épaiſſeur, & </s> <s xml:id="echoid-s1378" xml:space="preserve">à la diſtance où <lb/>ils ſeront poſés, afin qu’ils ſupléent à l’épaiſleur qu’on a donnée <lb/>de moins qu’il ne falloit au ſommet BC.</s> <s xml:id="echoid-s1379" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1380" xml:space="preserve">Pour cela nous nommerons BC, ou AE, a; </s> <s xml:id="echoid-s1381" xml:space="preserve">CE, c; </s> <s xml:id="echoid-s1382" xml:space="preserve">ED, d; </s> <s xml:id="echoid-s1383" xml:space="preserve">GA, y; </s> <s xml:id="echoid-s1384" xml:space="preserve">& </s> <s xml:id="echoid-s1385" xml:space="preserve"><lb/>nous ſupoſerons que n, marque toute l’épaiſſeur AD, de la baſe, afin <lb/>d’avoir n = a + d, & </s> <s xml:id="echoid-s1386" xml:space="preserve">que la puiſſance P, eſt toûjours exprimée par bf: <lb/></s> <s xml:id="echoid-s1387" xml:space="preserve">cela étant le poids Mſera ac, & </s> <s xml:id="echoid-s1388" xml:space="preserve">le poids N, ſera {dc/2}; </s> <s xml:id="echoid-s1389" xml:space="preserve">à l’égard du poids <lb/>L, il ſeroit exprimé par cy, ſi le rectangle F A, étoit le proſil d’un <lb/>mur qui regnât ſur toute la longueur du revêtement; </s> <s xml:id="echoid-s1390" xml:space="preserve">mais n’étant <lb/>que celui des contreforts, il faut comme nous l’avons dit dans l’art.</s> <s xml:id="echoid-s1391" xml:space="preserve"> <pb o="56" file="0082" n="84" rhead="LA SCIENCE DES INGENIEURS,"/> 40 avoir égard à leur diſtance & </s> <s xml:id="echoid-s1392" xml:space="preserve">à leur épaiſſeur. </s> <s xml:id="echoid-s1393" xml:space="preserve">Or ſi l’on ſupoſe que <lb/>de l’eſpace LMON, qui régne derriere le revêtement, il n’y en ait <lb/>qu’un quart qui ſoit occupé par les contreforts; </s> <s xml:id="echoid-s1394" xml:space="preserve">c’eſt-à-dire, que <lb/>donnant, par exemple, 4 pieds à l’épaiſſeur BC, ou EF, de chaque <lb/>contrefort, on en laiſſe 12 d’intervalle de C, en D, tous les con-<lb/>treforts pourront être exprimés par {cy/4}, de même que tout le revéte-<lb/>ment ABCD, par ac + {cd/2}, il ne s’agit donc plus que de réünir les poids <lb/>L, & </s> <s xml:id="echoid-s1395" xml:space="preserve">N, avec le poids M, pour ne faire enſemble qu’un ſeul poids <lb/>O, qui faſſe le même effet étant ſuſpendu au point I, par raport <lb/>au point d’apui, D, qu’ils font étant ſuſpendus en H, & </s> <s xml:id="echoid-s1396" xml:space="preserve">en K, pour <lb/>cela l’on ſait qu’il faut multiplier le poids N, ({cd/2}) par ſon bras <lb/>de levier KD, ({cd/3}) de même que le poids L, ({cy/4}) par ſon <lb/>bras de lévier HD, (n + {y/2}) & </s> <s xml:id="echoid-s1397" xml:space="preserve">diviſer chaque produit par le <lb/>bras ID, & </s> <s xml:id="echoid-s1398" xml:space="preserve">qu’alors l’on aura {{cyy + 2cny/8} + {cdd/3}/{a + 2d/2}} + ac, pour la va-<lb/>leur du poids O, or multipliant ce poids par ſon bras de lévier <lb/>ID, l’on aura un produit égal à celui de la puiſſance P, (bf,) <lb/>par ſon bras de lévier DQ, (c,) par conſéquent cette équation <lb/>{cyy + 2cny/8} + {cdd/3} + {caa + 2cad/2} = bcf, d’où effaçant c, & </s> <s xml:id="echoid-s1399" xml:space="preserve">faiſant paſſer <lb/>du premier membre dans le ſecond, les termes où l’inconnuë ne ſe <lb/>trouve point, l’on aura {yy + 2ny/8} = bf - {aa - 2ad/2} - {dd/3}; </s> <s xml:id="echoid-s1400" xml:space="preserve">ſi de cette <lb/>équation l’on fait évanoüir la fraction du premier membre & </s> <s xml:id="echoid-s1401" xml:space="preserve">qu’on <lb/>ajoûte nn, de part & </s> <s xml:id="echoid-s1402" xml:space="preserve">d’autre pour rendre le premier membre un <lb/>quarré parfait, l’on aura yy + 2ny + nn = 8bf - 4aa - 8ad - {8dd/3} <lb/>+ nn, d’où extrayant la racine quarrée & </s> <s xml:id="echoid-s1403" xml:space="preserve">dégageant l’inconnuë, <lb/>il viendra pour derniere équation y = √8bf - 4aa - 8ad - {8dd/3}\x{0020} <lb/>+ nn - n, qui donne ce que l’on cherchoit.</s> <s xml:id="echoid-s1404" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div110" type="section" level="1" n="72"> <head xml:id="echoid-head89" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s1405" xml:space="preserve">Pour ſavoir en nombre quelle doit être la longueur des contre- <pb o="57" file="0083" n="85" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> forts, il faut ſe rappeller que l’on a ſupoſé que la puiſſance bf, va-<lb/>loit 52 pieds 6 pouces 4 lignes, que a, valoit 3 pieds, d, 6. </s> <s xml:id="echoid-s1406" xml:space="preserve">& </s> <s xml:id="echoid-s1407" xml:space="preserve">a <lb/>+ d, ou n, vaudra donc 9 pieds; </s> <s xml:id="echoid-s1408" xml:space="preserve">ainſi en ſuivant ce qui eſt en-<lb/>ſeigné dans la derniere équation, l’on aura 8bf = 420 pieds 2 pou-<lb/>ces 8 lignes. </s> <s xml:id="echoid-s1409" xml:space="preserve">4aa = 36, 8ad = 144, {8dd/3} = 96, & </s> <s xml:id="echoid-s1410" xml:space="preserve">nn = 81. </s> <s xml:id="echoid-s1411" xml:space="preserve">Mais <lb/>cette équation montre auſſi qu’il faut ajoûter 8bf, avec nn; </s> <s xml:id="echoid-s1412" xml:space="preserve">c’eſt-<lb/>à-dire, 420 pieds 2 pouces 8 lignes, avec 81 pour avoir 501 <lb/>pieds 2 pouces 8 lignes, & </s> <s xml:id="echoid-s1413" xml:space="preserve">qu’il en faut ſouſtraire 4aa. </s> <s xml:id="echoid-s1414" xml:space="preserve">8ad & </s> <s xml:id="echoid-s1415" xml:space="preserve"><lb/>{8dd/3} ou leur valeur 36, 144, 96, qui font 276, & </s> <s xml:id="echoid-s1416" xml:space="preserve">de la difference <lb/>qui eſt 225 pieds 2 pouces 8 lignes, en extraire la racine quarrée, <lb/>qu’on trouvera d’environ 15 pieds, de laquelle ſouſtrayant n, qui <lb/>vaut 9 pieds, la difference ſera 6 pieds pour la valeur de y, ou, <lb/>ſi l’on veut, pour la longueur qu’il faudra donner aux contreforts.</s> <s xml:id="echoid-s1417" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div111" type="section" level="1" n="73"> <head xml:id="echoid-head90" style="it" xml:space="preserve"> <emph style="bf">Remarque prémiere.</emph> </head> <p> <s xml:id="echoid-s1418" xml:space="preserve">45. </s> <s xml:id="echoid-s1419" xml:space="preserve">Si l’on vouloit que les contreforts & </s> <s xml:id="echoid-s1420" xml:space="preserve">le revêtement au lieu <lb/>d’être en équilibre par leur réſiſtance avec la puiſſance P, fuſſent <lb/>capables de ſoûtenir l’effort d’une autre puiſſance qui ſeroit plus <lb/>forte d’un quart que celle-ci, il faudroit au lieu de ſupoſer bf, égal à <lb/>52 pieds 6 pouces 4 lignes, le ſupoſer de 65 pieds 8 pouces; </s> <s xml:id="echoid-s1421" xml:space="preserve">pour <lb/>lors les contreforts auront 9 pieds 6 pouces 4 lignes de longueur & </s> <s xml:id="echoid-s1422" xml:space="preserve"><lb/>non pas 6 pieds.</s> <s xml:id="echoid-s1423" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div112" type="section" level="1" n="74"> <head xml:id="echoid-head91" style="it" xml:space="preserve"> <emph style="bf">Remarque ſeconde.</emph> </head> <p> <s xml:id="echoid-s1424" xml:space="preserve">46. </s> <s xml:id="echoid-s1425" xml:space="preserve">Nous venons de ſupoſer que l’eſpace LMNO, qui regne der-<lb/> <anchor type="note" xlink:label="note-0083-01a" xlink:href="note-0083-01"/> riere le revêtement étoit rempli par un quart de maçonnerie & </s> <s xml:id="echoid-s1426" xml:space="preserve">par <lb/>trois quarts de terre, parce que l’intervalle AB, d’un contrefort <lb/>à l’autre, eſt triple de l’épaiſſeur BC, de chaque contrefort, & </s> <s xml:id="echoid-s1427" xml:space="preserve">c’eſt <lb/>pour cela que nous avons diviſé la longueur EB, par 4, parce qu’en <lb/>effet la ligne AC, qui vaut quatre parties égales peut-être regardée <lb/>comme le dénominateur d’une fraction, dont le numerateur eſt <lb/>égal à la partie BC, qui eſt un quart de toute la ligne AC; </s> <s xml:id="echoid-s1428" xml:space="preserve">mais ſi <lb/>l’on vouloit que les contreforts fuſſent plus près les uns des autres; <lb/></s> <s xml:id="echoid-s1429" xml:space="preserve">enſorte qu’ils ne fuſſent éloignés, par exemple, que du double de <lb/>leur épaiſſeur, pour lors l’étenduë qu’occuperont tous les contre-<lb/>forts ſera à celui qui regne entre les deux paralelles LM, & </s> <s xml:id="echoid-s1430" xml:space="preserve">NO, <lb/>comme un eſt à trois, ce qui fait voir qu’au lieu de diviſer la lon-<lb/>gueur inconnuë des contreforts; </s> <s xml:id="echoid-s1431" xml:space="preserve">c’eſt-à-dire, y par 4, il ne fau- <pb o="58" file="0084" n="86" rhead="LA SCIENCE DES INGENIEURS,"/> droit la diviſer que par 3, ou par 2, ſi l’on vouloit que les contre-<lb/>forts ne fuſſent diſtans les uns des autres que d’un intervalle égal à <lb/>leur épaiſſeur: </s> <s xml:id="echoid-s1432" xml:space="preserve">enfin ſi l’on vouloit que l’étenduë occupée par les <lb/>contreforts ſoit à tout l’eſpace renfermé par les paralelles comme <lb/>2 eſt à 5, il faudroit multiplier y par 2 & </s> <s xml:id="echoid-s1433" xml:space="preserve">le diviſer enſuite par 5, <lb/>parce qu’alors l’on aura {2y/5} qui exprimera la réduction des contre-<lb/>forts; </s> <s xml:id="echoid-s1434" xml:space="preserve">or comme 5 marque tout l’eſpace renfermé entre les para-<lb/>lelles, & </s> <s xml:id="echoid-s1435" xml:space="preserve">2 celui qui eſt occupé par les contreforts, ſi l’on retran-<lb/>che donc 2 de 5, il reſtera 3, & </s> <s xml:id="echoid-s1436" xml:space="preserve">les nombres deux & </s> <s xml:id="echoid-s1437" xml:space="preserve">trois marque-<lb/>ront le rapport de l’épaiſſeur des contreforts à leur diſtance: </s> <s xml:id="echoid-s1438" xml:space="preserve">il eſt <lb/>bon de faire attention à ceci, quoique ce ne ſoit qu’une bagatelle, <lb/>parce que dans le Probléme ſuivant où nous chercherons quel doit <lb/>être le raport de l’épaiſſeur des contreforts à leur diſtance, cela <lb/>pourra nous ſervir.</s> <s xml:id="echoid-s1439" xml:space="preserve"/> </p> <div xml:id="echoid-div112" type="float" level="2" n="1"> <note position="right" xlink:label="note-0083-01" xlink:href="note-0083-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> </div> <div xml:id="echoid-div114" type="section" level="1" n="75"> <head xml:id="echoid-head92" xml:space="preserve">PROPOSITION TROISIE’ME.</head> <head xml:id="echoid-head93" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s1440" xml:space="preserve"><emph style="bf">47.</emph> Ayant déterminé la longueur AG, des contreforts, <lb/> <anchor type="note" xlink:label="note-0084-01a" xlink:href="note-0084-01"/> l’épaiſſeur BC, du revêtement, & </s> <s xml:id="echoid-s1441" xml:space="preserve">ſa ligne de talud ED, on <lb/>demande quelle épaiſſeur ilfaudra donner aux contreforts par <lb/>rapport à la diſtance où il faudra les éloigner les uns des au-<lb/>tres pour que toute la Maçonnerie ſoit en équilibre avec la <lb/>puiſſance P, qui tireroit de C, en Q.</s> <s xml:id="echoid-s1442" xml:space="preserve"/> </p> <div xml:id="echoid-div114" type="float" level="2" n="1"> <note position="left" xlink:label="note-0084-01" xlink:href="note-0084-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> <p> <s xml:id="echoid-s1443" xml:space="preserve">On ſupoſe encore ici, comme on l’a fait ailleurs, que la puif-<lb/>ſance P, eſt beaucoup au-deſſus de la réſiſtance dont le revête-<lb/>ment ABCD, eſt capable par ſon poids, & </s> <s xml:id="echoid-s1444" xml:space="preserve">qu’ainſi il faut faire <lb/>des contreforts pour donner au revêtement la force qui lui man-<lb/>que: </s> <s xml:id="echoid-s1445" xml:space="preserve">or comme dans le Probléme précédent, nous avons cherché <lb/>quelle longueur il faloit donner à ces contreforts pour rencontrer <lb/>le point d’équilibre, ici l’on ſupoſe que cette longueur a été déter-<lb/>minée, & </s> <s xml:id="echoid-s1446" xml:space="preserve">qu’il s’agit ſeulement de ſavoir quel raport il doit y avoir <lb/>de l’épaiſſeur des contreforts à leur diſtance, afin qu’ils compoſent <lb/>enſemble un maſſif ſuffiſant pour rendre le revêtement capable de <lb/>ſoûtenir l’effort de la puiſſance.</s> <s xml:id="echoid-s1447" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1448" xml:space="preserve">Ayant nommé GA, h; </s> <s xml:id="echoid-s1449" xml:space="preserve">BA, c; </s> <s xml:id="echoid-s1450" xml:space="preserve">AE, a; </s> <s xml:id="echoid-s1451" xml:space="preserve">ED, d; </s> <s xml:id="echoid-s1452" xml:space="preserve">AD, n; </s> <s xml:id="echoid-s1453" xml:space="preserve">c’eſt- <pb o="59" file="0085" n="87" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> à-dire n = a + d, & </s> <s xml:id="echoid-s1454" xml:space="preserve">la puiſſance P, bf; </s> <s xml:id="echoid-s1455" xml:space="preserve">comme à l’ordinaire, l’on <lb/>aura {cd/2} pour le poids N, & </s> <s xml:id="echoid-s1456" xml:space="preserve">ac, pour le poids M; </s> <s xml:id="echoid-s1457" xml:space="preserve">quant au poids L, <lb/>comme il ne doit exprimer qu’une partie du rectangle GFBA, on <lb/>ne peut pas dire que ch, ſoit la valeur de ce poids, parce que ch, <lb/>doit être diviſé par une certaine grandeur qui determine le raport <lb/>de l’épaiſſeur des contreforts avec leur intervalle; </s> <s xml:id="echoid-s1458" xml:space="preserve">or comme on <lb/>ne connoît pas cette grandeur, nous la nommerons x, & </s> <s xml:id="echoid-s1459" xml:space="preserve">pour lors <lb/>le poids L, ſera {ch/x}. </s> <s xml:id="echoid-s1460" xml:space="preserve">Preſentement, ſi l’on réünit les trois poids L, <lb/>M, N, en un ſeul O, & </s> <s xml:id="echoid-s1461" xml:space="preserve">qu’on le multiplie par le bras de lévier ID, <lb/>l’on aura un produit égal à celui de la puiſſance P, par ſon bras de <lb/>lévier DQ, qui donnera cette équation {chh + 2cnb/2x} + {aac + 2adc/2} <lb/>+ {cdd/3} = bfc, dont je n’explique point les opérations qui l’ont for-<lb/>mée, parce qu’elles ſont les mêmes que celles de la propoſition <lb/>précédente, il ſuffira ſeulement de dire que pour avoir la valeur <lb/>de l’inconnuë x, il faut d’abord effacer c, de toute part, & </s> <s xml:id="echoid-s1462" xml:space="preserve">faire <lb/>paſſer {aa + 2da/2} + {dd/2} du premier membre dans le ſecond, afin d’avoir <lb/>{hb + 2nh/2x} = bf - {aa - 2da/2} - {dd/3} d’où faiſant évanoüir la fraction <lb/>du premier membre, il viendra hh + 2nh = 2xbf - xaa - 2xad <lb/>- {2xdd/3} or ſi l’on diviſe cette équation par 2bf - aa - 2ad <lb/>- {2dd/3} elle ſera changée en celle-ci 2bf-aa-2ad-{2dd/3} = x, <lb/>qui donne la valeur de x.</s> <s xml:id="echoid-s1463" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div116" type="section" level="1" n="76"> <head xml:id="echoid-head94" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s1464" xml:space="preserve">Supoſant que la puiſſance P, ſoit de 66 pieds, que GA, ou h, <lb/>ſoit de 7 pieds, ED, ou d, de 6, AE, ou a, de 3, l’on aura 9 <lb/>pour la valeur de n: </s> <s xml:id="echoid-s1465" xml:space="preserve">cela poſé, le dividende de l’équation précé-<lb/>dente ſera 175, & </s> <s xml:id="echoid-s1466" xml:space="preserve">le diviſeur ſera 63, ainſi faiſant la diviſion, l’on <lb/>aura pour quotient 2 + {7/9} ou ce qui eſt la même choſe {25/9} = x, <lb/>c’eſt-à-dire, qu’il faut diviſer ch, par {25/9} mais comme {ch/{25/9}} eſt la <pb o="60" file="0086" n="88" rhead="LA SCIENCE DES INGENIEURS,"/> même choſe que {9ch/25}, l’on voit que ſuprimant ch, qui eſt inutile, & </s> <s xml:id="echoid-s1467" xml:space="preserve"><lb/>retranchant le numerateur du dénominateur, il vient {9/16} qui mar-<lb/>que le raport de l’épaiſſeur qu’il faut donner aux contreforts avec <lb/>l’intervalle dont ils doivent être éloignés les uns des autres; </s> <s xml:id="echoid-s1468" xml:space="preserve">c’eſt-<lb/>à-dire, par exemple, que ſi l’on donnoit 4 pieds {1/2} d’épaiſſeur <lb/>aux contreforts, il faudroit les conſtruire a 8 pieds les uns des <lb/>autres.</s> <s xml:id="echoid-s1469" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div117" type="section" level="1" n="77"> <head xml:id="echoid-head95" xml:space="preserve">PROPOSITION QUATRIE’ME. <lb/><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s1470" xml:space="preserve"><emph style="bf">48.</emph> Ayant déterminé la longueur GA, des contreforts, <lb/> <anchor type="note" xlink:label="note-0086-01a" xlink:href="note-0086-01"/> leur épaiſſeur & </s> <s xml:id="echoid-s1471" xml:space="preserve">leur diſtance, de même que la ligne de <lb/>ED, & </s> <s xml:id="echoid-s1472" xml:space="preserve">la hauteur CE, l’on demande qu’elle épaiſſeur il <lb/>faudra donner au ſommet BC, du revêtement pour qu’il <lb/>ſoit en équilibre par ſon poids avec une puiſſance qui tire-<lb/>roit de C, en Q.</s> <s xml:id="echoid-s1473" xml:space="preserve"/> </p> <div xml:id="echoid-div117" type="float" level="2" n="1"> <note position="left" xlink:label="note-0086-01" xlink:href="note-0086-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> <p> <s xml:id="echoid-s1474" xml:space="preserve">Nous nommerons GA, h; </s> <s xml:id="echoid-s1475" xml:space="preserve">ED, d; </s> <s xml:id="echoid-s1476" xml:space="preserve">la hauteur CE, c; </s> <s xml:id="echoid-s1477" xml:space="preserve">l’épaiſſeur <lb/>BC, ou AE, x; </s> <s xml:id="echoid-s1478" xml:space="preserve">& </s> <s xml:id="echoid-s1479" xml:space="preserve">la puiſſance bf, comme à l’ordinaire; </s> <s xml:id="echoid-s1480" xml:space="preserve">or com-<lb/>me l’on ſupoſe que l’eſpace occupé par les contreforts eſt à toute <lb/>l’étenduë LMNO, comme 2 eſt à 5, la reduction des contreforts, <lb/>ou ſi l’on veut, la valeur du poids L, ſera donc {2hc/5}, le poids M, <lb/>ſera xc, & </s> <s xml:id="echoid-s1481" xml:space="preserve">le poids N, {cd/2}; </s> <s xml:id="echoid-s1482" xml:space="preserve">ſi préſentement l’on réünit ces trois <lb/>poids dans un ſeul O, & </s> <s xml:id="echoid-s1483" xml:space="preserve">qu’on multiplie enſuite ce poids par le bras <lb/>ID, l’on aura comme ci-devant un produit égal à celui de la puiſ-<lb/>ſance P, par ſon bras de lévier DQ. </s> <s xml:id="echoid-s1484" xml:space="preserve">par conſéquent cette équation <lb/>{xxc/2} + xcd + {2xhc/5} + {hhc/5} + {2hdc/5} + {ddc/3} = bfc, d’où faiſant paſſer du pre-<lb/>mier membre dans le ſecond les termes où l’inconnuë ne ſe trouve <lb/>point, & </s> <s xml:id="echoid-s1485" xml:space="preserve">diviſant le tout par c, l’on aura {xx/2} + xd + {2xh/5} = bf - {hh/5} <lb/>- {2hd/5} - {dd/3}, mais ſi l’on ſupoſe n = d + {2h/5} l’on aura nx, <lb/>= dx + {2hx/5} & </s> <s xml:id="echoid-s1486" xml:space="preserve">mettant nx, à la place de ſa valeur dans l’équation <pb o="61" file="0087" n="89" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> précédente, & </s> <s xml:id="echoid-s1487" xml:space="preserve">multipliant le tout par 2 pour faire évanoüir la frac-<lb/>tion {xx/2} elle ſera changée en celle-ci, xx + 2nx = 2bf - {2hh/5} <lb/>- {4dh/5} - {2dd/3} à laquelle ajoûtant nn, de part & </s> <s xml:id="echoid-s1488" xml:space="preserve">d’autre, il viendra <lb/>xx + 2nx + nn = 2bf + nn - {2bh/4} - {4dh/5} - {2dd/3}; </s> <s xml:id="echoid-s1489" xml:space="preserve">or ſi de cette <lb/>équation l’on en extrait la racine quarrée, & </s> <s xml:id="echoid-s1490" xml:space="preserve">qu’on dégage en-<lb/>ſuite l’inconnuë, on aura cette derniere équation, <lb/>x = √2bf + nn - {2hh/4} - {4dh/5} - {2dd/3}\x{0020} - n, qui donne ce que <lb/>l’on cherche.</s> <s xml:id="echoid-s1491" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div119" type="section" level="1" n="78"> <head xml:id="echoid-head96" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s1492" xml:space="preserve">Si l’on ſupoſe que la puiſſance bf, ſoit de 55 pieds & </s> <s xml:id="echoid-s1493" xml:space="preserve">que GA, <lb/>(h) ſoit de 5, & </s> <s xml:id="echoid-s1494" xml:space="preserve">la ligne de talud ED, de 4, l’on n’aura qu’à faire <lb/>les mêmes opérations par les nombres que celles qui ſont indiquées <lb/>dans la derniere équation, & </s> <s xml:id="echoid-s1495" xml:space="preserve">l’on trouvera que l’épaiſſeur BC, ou <lb/>AE, doit être de 4 pieds 5 pouces 4 lignes, pour que le revête-<lb/>ment joint aux contreforts ſoit en équilibre avec la puiſſance.</s> <s xml:id="echoid-s1496" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div120" type="section" level="1" n="79"> <head xml:id="echoid-head97" style="it" xml:space="preserve"> <emph style="bf">Remarque.</emph> </head> <p> <s xml:id="echoid-s1497" xml:space="preserve">49. </s> <s xml:id="echoid-s1498" xml:space="preserve">Après qu’on aura trouvé le point d’équilibre au ſujet de quel-<lb/>qu’un des Problémes précédens, on pourra mettre le revêtement <lb/>& </s> <s xml:id="echoid-s1499" xml:space="preserve">les contreforts au-deſſus de la pouſſée des terres, ſoit en donnant <lb/>un peu plus d’épaiſſeur au ſommet, ou en augmentant la ligne de <lb/>talud ou la longueur des contreforts, je n’en donne point d’exemple, <lb/>parce que ceci peut ſe faire ſans aucune difficulté.</s> <s xml:id="echoid-s1500" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div121" type="section" level="1" n="80"> <head xml:id="echoid-head98" style="it" xml:space="preserve"> <emph style="bf">Examen des differentes Figures qu’on peut donner à la baſe des <lb/>contreforts.</emph> </head> <p> <s xml:id="echoid-s1501" xml:space="preserve">50. </s> <s xml:id="echoid-s1502" xml:space="preserve">On a inſinué au commencement de ce Chapitre, qu’il fal-<lb/>loit avoir égard à la figure qu’il convenoit de donner à la baſe des <lb/>contreforts, ſelon les differens uſages des murs auſquels ils ſeroient <lb/>apliqués; </s> <s xml:id="echoid-s1503" xml:space="preserve">comme c’eſt ici l’endroit d’en examiner toutes les cir-<lb/>conſtances, voici ce qui m’a parû qu’on pouvoit dire ſur ce ſu-<lb/>jet.</s> <s xml:id="echoid-s1504" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1505" xml:space="preserve">Quand il s’agit des murs qui ne ſoûtiennent aucune pouſſée com-<lb/>me ſont ceux de clôture, & </s> <s xml:id="echoid-s1506" xml:space="preserve">qu’on juge à propos d’y faire des con- <pb o="62" file="0088" n="90" rhead="LA SCIENCE DES INGENIEURS,"/> treforts, il ſemble qu’il eſt aſſés indifferent de donner à leur baſe <lb/>telle figure que l’on voudra, parce que dans ce cas, les contre-<lb/>forts ne ſervent guere qu’à donner plus d’aſſiette aux murs, & </s> <s xml:id="echoid-s1507" xml:space="preserve">com-<lb/>me on a coûtume de faire leur baſe rectangulaire, il ne ſera pas <lb/>mal de ſuivre l’uſage, c’eſt pourquoi nous ne nous y arrêterons <lb/>point.</s> <s xml:id="echoid-s1508" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1509" xml:space="preserve">Mais quand les contreforts ſont apliqués derriere des revêtemens, <lb/>qui doivent ſoûtenir des terres & </s> <s xml:id="echoid-s1510" xml:space="preserve">autres poids conſidérables, la baſe <lb/>qui convient le mieux eſt de la faire comme ECDF; </s> <s xml:id="echoid-s1511" xml:space="preserve">c’eſt-à-dire, <lb/> <anchor type="note" xlink:label="note-0088-01a" xlink:href="note-0088-01"/> lui donner plus de largeur à la queuë CD, qu’à la racine EF, par-<lb/>ce que le centre de gravité au lieu d’être dans le milieu de ſa lon-<lb/>gueur, comme au rectangle AB, ſera plus éloigné du point d’apui, <lb/>par conſéquent le bras de lévier, qui répond au poids, devenant plus <lb/>long, le revêtement ſera capable d’une plus grande réſiſtance qu’au-<lb/>paravant avec la même quantité de maçonnerie; </s> <s xml:id="echoid-s1512" xml:space="preserve">& </s> <s xml:id="echoid-s1513" xml:space="preserve">ſi j’ai ſupoſé <lb/>rectangulaire la baſe des contreforts qui ont eu lieu dans les pro-<lb/>poſitions précédentes, ce n’eſt pas que j’aie voulu montrer qu’il <lb/>falloit la faire ainſi, ç’a été ſeulement pour agir avec plus de ſim-<lb/>plicité.</s> <s xml:id="echoid-s1514" xml:space="preserve"/> </p> <div xml:id="echoid-div121" type="float" level="2" n="1"> <note position="left" xlink:label="note-0088-01" xlink:href="note-0088-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 9.</note> </div> <p> <s xml:id="echoid-s1515" xml:space="preserve">Si les contreforts ſont en dehors, c’eſt-à-dire, opoſés à la pouſ-<lb/>ſée de la puiſſance qui agit, comme aux piés-droits des Voûtes, il <lb/>faut au contraire faire leurs baſes plus larges à la racine qu’à la queuë <lb/>comme IHGK, parce que le centre de gravité ſera plus éloigné <lb/> <anchor type="note" xlink:label="note-0088-02a" xlink:href="note-0088-02"/> du point d’apui, & </s> <s xml:id="echoid-s1516" xml:space="preserve">que le bras de lévier qui répond au poids ſe <lb/>trouvera encore allongé comme dans le cas précédent, mais dans <lb/>un ſens contraire, ce qui donnera beaucoupplus de force aux piés-<lb/>droits & </s> <s xml:id="echoid-s1517" xml:space="preserve">aux contreforts. </s> <s xml:id="echoid-s1518" xml:space="preserve">Je ne parle pas de pluſieurs autres figures <lb/>qu’on pourroit donner à la baſe des contreforts pour fortifier en-<lb/>core davantage les revêtemens, parce que ces figures dépendroient <lb/>de certaines courbes qu’il ſeroit bien difficile de faire entendre, non-<lb/>ſeulement aux maçons, mais même à ceux qui les dirigent, j’ai de <lb/>la répugnance auſſi-bien qu’eux pour tout ce qui n’eſt pas d’une <lb/>utilité eſſentielle, ſur-tout dans les choſes qui demandent d’être <lb/>executées par des voyes ſimples.</s> <s xml:id="echoid-s1519" xml:space="preserve"/> </p> <div xml:id="echoid-div122" type="float" level="2" n="2"> <note position="left" xlink:label="note-0088-02" xlink:href="note-0088-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 9.</note> </div> <p> <s xml:id="echoid-s1520" xml:space="preserve">Mais pour juger exactement de la réſiſtance dont les revêtemens <lb/>peuvent être capables par raport à la figure qu’on donnera à leurs <lb/>contreforts, nous ſupoſerons que le profil Lr, apartient à trois re-<lb/>vêtemens differens, dont le premier auroit tous ſes contreforts <lb/>comme AB, le ſecond comme CF, & </s> <s xml:id="echoid-s1521" xml:space="preserve">le troiſiéme comme HK; <lb/></s> <s xml:id="echoid-s1522" xml:space="preserve"> <anchor type="note" xlink:label="note-0088-03a" xlink:href="note-0088-03"/> que ces contreforts ſont égaux enſuperficie, & </s> <s xml:id="echoid-s1523" xml:space="preserve">que par conſéquent <lb/>la quantité de maçonnerie eſt égale pour chacun des revêtemens.</s> <s xml:id="echoid-s1524" xml:space="preserve"> <pb o="63" file="0089" n="91" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> Cela poſé, remarqués que dans le rectangle AB, le centre de gra-<lb/>vité eſt au point O, milieu de la longueur LR (par l’art. </s> <s xml:id="echoid-s1525" xml:space="preserve">I.) </s> <s xml:id="echoid-s1526" xml:space="preserve">qui ré-<lb/>pond auſſi au profil: </s> <s xml:id="echoid-s1527" xml:space="preserve">mais qu’il n’en eſt pas de même de l’autre plan <lb/>CF, puiſque pour avoir ſon centre de gravité, ſelon l’art. </s> <s xml:id="echoid-s1528" xml:space="preserve">10. </s> <s xml:id="echoid-s1529" xml:space="preserve">il <lb/>faut diviſer la ligne LR, en trois également, enſuite couper la par-<lb/>tie du milieu MQ, au point N, de maniere que NM, ſoit à NQ, <lb/>comme EF, eſt à CD; </s> <s xml:id="echoid-s1530" xml:space="preserve">or ayant fait CD, double de EF, NQ, ſera <lb/>double de NM, par conſequent le point N, ſera le centre de gra-<lb/>vité; </s> <s xml:id="echoid-s1531" xml:space="preserve">mais dans le profil, le poids qui exprimera le contrefort pé-<lb/>ſera plus en N, qu’en O, dans la raiſon de NZ, à OZ, qu’on doit <lb/>regarder comme des bras de léviers dont le point d’apui eſt en Z, <lb/>par conſéquent le contrefort CF, réſiſtera plus que AB, dans la rai-<lb/>ſon des lignes NZ, & </s> <s xml:id="echoid-s1532" xml:space="preserve">OZ.</s> <s xml:id="echoid-s1533" xml:space="preserve"/> </p> <div xml:id="echoid-div123" type="float" level="2" n="3"> <note position="left" xlink:label="note-0088-03" xlink:href="note-0088-03a" xml:space="preserve"><emph style="sc">Fig</emph>. 8. <lb/>& 9.</note> </div> <p> <s xml:id="echoid-s1534" xml:space="preserve">Cependant le contrefort CF, réſiſtera encore bien davantage que <lb/>HK, ſi la ligne GK, eſt double de HI, car pour lors MP, ſera <lb/>double de PQ, parce que le centre de gravité ſera au point P, & </s> <s xml:id="echoid-s1535" xml:space="preserve"><lb/>le poids qui y ſera ſuſpendu ne péſera pas tant que s’il étoit en O, <lb/>& </s> <s xml:id="echoid-s1536" xml:space="preserve">encore moins que s’il étoit en N, dans la raiſon que PZ, ſera <lb/>plus petit que NZ.</s> <s xml:id="echoid-s1537" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1538" xml:space="preserve">Il ſuit de ce que l’on vient de dire, que plus les lignes égales <lb/>CD, & </s> <s xml:id="echoid-s1539" xml:space="preserve">GK, ſeront plus grandes que EF, & </s> <s xml:id="echoid-s1540" xml:space="preserve">HI, plus le contre-<lb/>fort CF, aura ſa réſiſtance au-deſſus de HK, quand les baſes de <lb/>ces deux contreforts ſeront égales en ſuperficie.</s> <s xml:id="echoid-s1541" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1542" xml:space="preserve">Voulant exprimer d’une maniere generale, la reſiſtance dont cha-<lb/>cun des trois revêtemens eſt capable, nous nommerons RV, a; <lb/></s> <s xml:id="echoid-s1543" xml:space="preserve">VZ, d; </s> <s xml:id="echoid-s1544" xml:space="preserve">Vr, c; </s> <s xml:id="echoid-s1545" xml:space="preserve">RZ, q; </s> <s xml:id="echoid-s1546" xml:space="preserve">LR, h; </s> <s xml:id="echoid-s1547" xml:space="preserve">& </s> <s xml:id="echoid-s1548" xml:space="preserve">le tiers de la même ligne LR, n; </s> <s xml:id="echoid-s1549" xml:space="preserve"><lb/>l’on aura {aac + 2acd/2} + {cdd/3} pour le rectangle Rr, & </s> <s xml:id="echoid-s1550" xml:space="preserve">le triangle <lb/>de talud réüni autour du point T, multiplié par le bras de lévier <lb/>TZ; </s> <s xml:id="echoid-s1551" xml:space="preserve">d’autre côté ch, exprimera la valeur du rectangle des contre-<lb/>forts, & </s> <s xml:id="echoid-s1552" xml:space="preserve">ſi l’on ſupoſe que ſelon l’Article 46, la maçonnerie de ces <lb/>contreforts occupe un tiers de l’eſpace qui eſt entre la queuë & </s> <s xml:id="echoid-s1553" xml:space="preserve">la <lb/>racine, l’on aura {ch/3} pour la valeur des contreforts réduite, qu’il <lb/>faut multiplier par les bras des léviers OZ ({2q + 3n/2}) NZ ({3q + 5n/3}) <lb/>PZ ({3q + 4n/3}) dont les produits ſeront {2cbq + 3chn/6}, {3chq + 5hcn/9}, <lb/>{3chq + 4chn/9} qu’il faudroit diviſer par TZ, pour réünir chaque poids <lb/>au point T; </s> <s xml:id="echoid-s1554" xml:space="preserve">mais comme ces grandeurs doivent-être enſuite mul- <pb o="64" file="0090" n="92" rhead="LA SCIENCE DES INGENIEURS,"/> tipliées par la même ligne TZ, quand on voudra former les équa-<lb/>tions des poids & </s> <s xml:id="echoid-s1555" xml:space="preserve">des puiſſances par leur bras de léviers, on ſe con-<lb/>tentera d’ajouter chacun de ſes produits avec {aac + 2acd/2} + {ddc/3} <lb/>ainſi nommant x, la puiſſance qui ſera en équilibre avec le premier <lb/>revêtement des contreforts AB, l’on aura {aa + 2ad/2} + {dd/3} + {2hq + 3hn/6} <lb/>= x, nommant y, celle du revêtement dont les contreforts ſeront <lb/>comme CF, l’on aura {aa + 2ad/2} + {dd/3} + {3hq + 5hn/9} = y, enfin nom-<lb/>mant z, la puiſſance qui eſt en équilibre avec la réſiſtance du <lb/>revêtement, dont les contreforts ſont comme HK, l’on aura <lb/>{aa + 2ad/2} + {3hq/3} + {3hq + 4hn/9} = z, par conſéquent ſi on donne des <lb/>valeurs en nombre aux lignes qui ſont exprimées par les lettres qui <lb/>compoſent les premiers membres des équations précédentes, il ſera <lb/>aiſé de connoître le raport des trois puiſſances, x, y, z, qui fera <lb/>voir de combien ces revêtemens ont plus de force les uns que les <lb/>autres.</s> <s xml:id="echoid-s1556" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1557" xml:space="preserve">Il ſuit de tout ce que l’on vient de voir, que ſi l’on veut faire <lb/>des revêtemens qui ayent la même hauteur, & </s> <s xml:id="echoid-s1558" xml:space="preserve">des pouſſées égales <lb/>à ſoûtenir, que pour les mettre en équilibre, on ſera contraint de <lb/>donner plus d’épaiſſeur au ſommet de ceux qui auront leurs con-<lb/>treforts comme HK, que s’ils les avoient comme CF.</s> <s xml:id="echoid-s1559" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1560" xml:space="preserve">Je ne ſais par quelle raiſon on fait ordinairement les contreforts <lb/>des revêtemens de fortification plûtôt comme HK, que comme <lb/>CF, ſi ce n’eſt pour les lier davantage à la muraille, puiſque ſi l’on <lb/>en excepte ce motif qui eſt de conſéquence, ſur-tout quand on n’a <lb/>pas de bons matériaux, on ne peut pas douter qu’il ne faille beau-<lb/>coup plus de maçonnerie, ſelon la premiere maniere, queſelon la ſe-<lb/>conde, pour faire le même effet: </s> <s xml:id="echoid-s1561" xml:space="preserve">il y en a qui veulent que ce ſoit <lb/>pour diminuer la pouſſée des Terres; </s> <s xml:id="echoid-s1562" xml:space="preserve">mais c’eſt une erreur, puiſ-<lb/>qu’elles agiront de même, de quelque façon que les contreforts <lb/>ſoient, comme il eſt aiſé de le prouver. </s> <s xml:id="echoid-s1563" xml:space="preserve">D’autres prétendent que <lb/>c’eſt afin qu’ils ſoûtiennent plus long-tems la violence du Canon <lb/>quand on bat en brêche, & </s> <s xml:id="echoid-s1564" xml:space="preserve">qu’ils empêchent que la chemiſe d’un <lb/>Ouvrage ne ſoit pas ſi-tôt ruinée: </s> <s xml:id="echoid-s1565" xml:space="preserve">cette raiſon n’eſt pas meilleure que <lb/>la précédente, comme on le va voir.</s> <s xml:id="echoid-s1566" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1567" xml:space="preserve">Supoſant que la muraille ait été ruinée juſqu’à la racine des con-<lb/>treforts, on ſait bien que quand les batteries des aſſiégeans en ſont <lb/>là, les contreforts ne ſont pas un petit obſtacle à l’avancement de <pb o="65" file="0091" n="93" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> la brêche, puiſqu’ayant moins de priſe que le reſte, ce n’eſt pas <lb/>ſans difficulté que l’ennemi parvient à les raſer, au point de ren-<lb/>dre la brêche praticable. </s> <s xml:id="echoid-s1568" xml:space="preserve">Or, la queſtion ſe réduit à ſavoir lequel <lb/>des deux contreforts CF, ou HK, ſoûtiendra plus long-tems le choc <lb/>des boulets; </s> <s xml:id="echoid-s1569" xml:space="preserve">pour en juger, nous les examinerons comme s’ils <lb/>étoient détachés du revêtement.</s> <s xml:id="echoid-s1570" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1571" xml:space="preserve">On ne peut pas diſconvenir que la face FH, étant celle qui ſe <lb/> <anchor type="note" xlink:label="note-0091-01a" xlink:href="note-0091-01"/> préſente à l’ennemi, ne ſoit plûtôt détruite que l’autre BC, parce <lb/>que les angles aigus F, & </s> <s xml:id="echoid-s1572" xml:space="preserve">H, ont peu de ſolidité; </s> <s xml:id="echoid-s1573" xml:space="preserve">& </s> <s xml:id="echoid-s1574" xml:space="preserve">comme ce <lb/>qui reſtera du contrefort va toûjours en diminuant vers la queuë, <lb/>l’ébranlement augmentant à meſure que les premieres parties ſeront <lb/>détachées, la deſtruction totale ſera bien-tôt achevée.</s> <s xml:id="echoid-s1575" xml:space="preserve"/> </p> <div xml:id="echoid-div124" type="float" level="2" n="4"> <note position="right" xlink:label="note-0091-01" xlink:href="note-0091-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 10. <lb/>& 11.</note> </div> <p> <s xml:id="echoid-s1576" xml:space="preserve">Il n’en eſt pas de même ſelon l’autre figure; </s> <s xml:id="echoid-s1577" xml:space="preserve">car comme la face <lb/>BC, préſente un plus petit front, elle ſera moins en priſe, les an-<lb/>gles obtus B & </s> <s xml:id="echoid-s1578" xml:space="preserve">C ſe ſoûtiendront davantage que les autres F & </s> <s xml:id="echoid-s1579" xml:space="preserve"><lb/>H. </s> <s xml:id="echoid-s1580" xml:space="preserve">D’ailleurs les faces AB, & </s> <s xml:id="echoid-s1581" xml:space="preserve">BC, ne ſe préſentant que de biais, le <lb/>boulet ne les choquera point avec la force abſoluë, ainſi la deſ-<lb/>truction ne pourra ſe faire que ſucceſſivement, à meſure que les par-<lb/>ties qui ſont immédiatement derriere la ligne BC, ſeront détruites; <lb/></s> <s xml:id="echoid-s1582" xml:space="preserve">& </s> <s xml:id="echoid-s1583" xml:space="preserve">je ne doute nullement que s’il faut 40 coups de Canon pour <lb/>raſer le contrefort FH, il n’en faille plus de 60 pour le contrefort <lb/>AC; </s> <s xml:id="echoid-s1584" xml:space="preserve">& </s> <s xml:id="echoid-s1585" xml:space="preserve">comme il arrivera la même choſe à tous les autres qui ac-<lb/>compagneront ce dernier dans l’étenduë de la brêche, on ne peut <lb/>pas conteſter qu’un revêtement dont les contreforts ſont plus épais <lb/>à la queuë qu’à la racine, ne ſe ſoûtiennent bien plus long-tems que <lb/>s’ils étoient faits comme on les pratique ordinairement. </s> <s xml:id="echoid-s1586" xml:space="preserve">Au reſte <lb/>je ne veux rien décider abſolument là-deſſus, j’expoſe mes refle-<lb/>xions, on en fera l’uſage qu’on jugera à propos; </s> <s xml:id="echoid-s1587" xml:space="preserve">ce que je pourrois <lb/>dire pour juſtifier ce que j’avance quelquefois, qui n’eſt pas con-<lb/>forme à l’uſage, c’eſt que je ne rapporte rien qui ne ſoit établi ſur <lb/>des démonſtrations.</s> <s xml:id="echoid-s1588" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1589" xml:space="preserve">Pour lier cette diſſertation avec les propoſitions de ce Chapitre, <lb/>il eſt à propos de faire remarquer, que ſoit qu’on ſe ſerve des con-<lb/> <anchor type="note" xlink:label="note-0091-02a" xlink:href="note-0091-02"/> treforts comme CF, ou comme HK, on réſoudra tous les Problé-<lb/>mes précédens de la même façon que ſi ces contreforts étoient <lb/>comme AB, puiſqu’il n’y aura d’autre difference que dans la ſitua-<lb/>tion du centre de gravité; </s> <s xml:id="echoid-s1590" xml:space="preserve">c’eſt pourquoi quand ils ſeront comme <lb/>CF, il faudra multiplier la ſuperficie des contreforts par la ligne <lb/>NZ, & </s> <s xml:id="echoid-s1591" xml:space="preserve">quand on les fera comme HK, il faudra la multiplier par <lb/>PZ, & </s> <s xml:id="echoid-s1592" xml:space="preserve">non pas par OZ, à cauſe que le bras de lévier eſt augmenté <lb/>dans le premier cas, & </s> <s xml:id="echoid-s1593" xml:space="preserve">diminué dans le ſecond: </s> <s xml:id="echoid-s1594" xml:space="preserve">à cela près, tout <pb o="66" file="0092" n="94" rhead="LA SCIENCE DES INGENIEURS,"/> le reſte ſe fera comme il a été enſeigné.</s> <s xml:id="echoid-s1595" xml:space="preserve"/> </p> <div xml:id="echoid-div125" type="float" level="2" n="5"> <note position="right" xlink:label="note-0091-02" xlink:href="note-0091-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 9.</note> </div> <p> <s xml:id="echoid-s1596" xml:space="preserve">Mr. </s> <s xml:id="echoid-s1597" xml:space="preserve">Delormes, me voyant travailler à cet Ouvrage, me dit qu’ayant <lb/>démoli dans la derniere Guerre pluſieurs Places du Duc de <lb/>Savoye, entr’autres Pignerol, Verceilles, Hivrée, & </s> <s xml:id="echoid-s1598" xml:space="preserve">Veruë, il avoit re-<lb/>marqué que tous les contreforts des revêtemens de ces Places <lb/>étoient liés enſemble par une Arcade, qui alloit ſe terminer à la hau-<lb/>teur du. </s> <s xml:id="echoid-s1599" xml:space="preserve">cordon, & </s> <s xml:id="echoid-s1600" xml:space="preserve">qu’au-deſſus des Arcades & </s> <s xml:id="echoid-s1601" xml:space="preserve">des contreforts, <lb/>il regnoit une eſpece de banquette ſur laquelle repoſoit la plus <lb/>grande partie des Terres du Parapet: </s> <s xml:id="echoid-s1602" xml:space="preserve">cela lui a fait penſer, que pour <lb/>fortifier les revêtemens contre la pouſſée des Terres, l’effet du <lb/>Canon, & </s> <s xml:id="echoid-s1603" xml:space="preserve">empêcher que la brêche ne ſe fit ſi-tôt, on pourroit dans <lb/>l’entre-deux des contreforts faire une Arcade, qui, régnant ſur toute <lb/>leur longueur, contribuëroit beaucoup à rendre le revêtement plus <lb/>ſolide, ſans être obligé de lui donner tant d’épaiſſeur au ſommet, <lb/>ſur-tout quand il s’agiroit d’une hauteur de Rempart conſidérable; <lb/></s> <s xml:id="echoid-s1604" xml:space="preserve">& </s> <s xml:id="echoid-s1605" xml:space="preserve">ſon deſſein ſeroit, que faiſant ces Arcades en plein ceintre, la <lb/>hauteur ſous la clef fut environ les deux tiers de toute la hauteur <lb/>du revêtement ou des contreforts depuis la retraite juſqu’au cor-<lb/>don. </s> <s xml:id="echoid-s1606" xml:space="preserve">L’avantage de cette conſtruction eſt que l’ennemi, après avoir <lb/>ruïné la chemiſe, ſeroit encore, non-ſeulement dans la néceſſité de <lb/>battre les contreforts, mais auſſi de détruire les Arcades qui ſe-<lb/>roient d’un grand obſtacle à l’éboulement des Terres & </s> <s xml:id="echoid-s1607" xml:space="preserve">à l’avan-<lb/>cement de la brêche; </s> <s xml:id="echoid-s1608" xml:space="preserve">deſorte qu’à le bien prendre, il auroit deux <lb/>revêtemens pour un à ruiner.</s> <s xml:id="echoid-s1609" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1610" xml:space="preserve">Je viens d’aprendre que Mr. </s> <s xml:id="echoid-s1611" xml:space="preserve">du Vivier, Ingénieur en Chef de <lb/>Charlemont, a propoſé depuis peu un nouveau ſiſtême de revête-<lb/>ment, dans lequel il employe quatre Arcades l’une ſur l’autre pour <lb/>lier les contreforts; </s> <s xml:id="echoid-s1612" xml:space="preserve">& </s> <s xml:id="echoid-s1613" xml:space="preserve">par-là le revêtement devient ſi ſolide, qu’il <lb/>lui ſuffit de donner trois pieds d’épaiſſeur ſur la retraite comme au <lb/>ſommet, parce qu’il eſt fait à plomb devant & </s> <s xml:id="echoid-s1614" xml:space="preserve">derriere, ſans doute <lb/>pour ne point expoſer le parement aux injures de l’air, qui eſt une <lb/>précaution que j’aprouverai toûjours, malgré tout ce que j’ai pû <lb/>dire en faveur des taluds; </s> <s xml:id="echoid-s1615" xml:space="preserve">mais comme ce n’a été que dans l’eſprit <lb/>d’une Théorie qui ne doit rien laiſſer échaper de tout ce qui mé-<lb/>rite quelque attention, j’ai toûjours entendu, que quand il ſeroit <lb/>queſtion d’élever des murs, on ne doit point ſe ſervir de mes re-<lb/>marques au préjudice des attentions qu’on doit avoir dans la pra-<lb/>tique par raport à la qualité des materiaux qu’on employe & </s> <s xml:id="echoid-s1616" xml:space="preserve">aux <lb/>autres circonſtances inſéparables de l’objet que l’on a en vûë: </s> <s xml:id="echoid-s1617" xml:space="preserve">pour <lb/>tout dire en un mot, quand on aura occaſion de donner beaucoup <lb/>de talud à un mur ſans qu’il devienne contraire à ſa durée, on ne <pb o="67" file="0093" n="95" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> doit point y manquer, parce qu’il faudra moins de Maçonnerie; <lb/></s> <s xml:id="echoid-s1618" xml:space="preserve">mais ſi l’on s’aperçoit qu’il puiſſe devenir nuiſible dans la ſuite, il <lb/>vaut mieux lui en donner moins & </s> <s xml:id="echoid-s1619" xml:space="preserve">ne point s’embaraſſer ſi l’on em-<lb/>ploye plus de matériaux, il arrivera toûjours que ſi l’on perd d’un <lb/>côté l’on gagnera de l’autre.</s> <s xml:id="echoid-s1620" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1621" xml:space="preserve">Je prévois que bien des gens, qui ne jugent des choſes que ſu-<lb/>perficielement, & </s> <s xml:id="echoid-s1622" xml:space="preserve">même ſouvent ſansles entendre, diront peut-être <lb/>après avoir lû ce que je viens d’écrire, que j’aurois pû me diſpen-<lb/>ſer de prendre tant de peine pour développer un ſujet ſur lequel on <lb/>ſait à quoi s’en tenir depuis long-tems, puiſque je ne dois point <lb/>ignorer que Mr. </s> <s xml:id="echoid-s1623" xml:space="preserve">de Vauban a donné un Profil qui convient à toute <lb/>ſorte de Rempars. </s> <s xml:id="echoid-s1624" xml:space="preserve">Je ne diſconviens pas que ce Profil ne ſoit <lb/>bien imaginé: </s> <s xml:id="echoid-s1625" xml:space="preserve">mais, qu’il me ſoit permis de demander ſi l’on a quel-<lb/>que certitude de la juſteſſe de ſes dimenſions; </s> <s xml:id="echoid-s1626" xml:space="preserve">car, comme il n’eſt <lb/>établi ſur aucun principe démontré, il pouroit bien n’être pas ſi <lb/>juſte qu’on ſe l’eſt imaginé: </s> <s xml:id="echoid-s1627" xml:space="preserve">ce n’eſt pas au reſte que je veüille en <lb/>diminuër le mérite, je fais trop de cas de tout ce qui vient de ſon il-<lb/>luſtre Auteur, pour m’emanciper dans une cenſure, qui me ſiéroit <lb/>mal; </s> <s xml:id="echoid-s1628" xml:space="preserve">mais, comme le reſpect qu’on doit à la memoire des grands-hom-<lb/>mes ne nous oblige point à recevoir aveuglement tout ce qui vient <lb/>d’eux, je vais faire un Paralelle du Profil général avec les Régles <lb/>que je viens d’établir.</s> <s xml:id="echoid-s1629" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div127" type="section" level="1" n="81"> <head xml:id="echoid-head99" style="it" xml:space="preserve"> <emph style="bf">51. Paralelle du Profil general de Mr. de Vauban avec <lb/>les Régles des Chapitres précédens.</emph> </head> <p> <s xml:id="echoid-s1630" xml:space="preserve">Mr. </s> <s xml:id="echoid-s1631" xml:space="preserve">de Vauban s’étant aperçû que les anciens Ingenieurs n’é-<lb/>toient point d’accord ſur les dimenſions qu’il falloit donner aux <lb/>revêtemens de Maçonnerie, les uns les faiſant d’une épaiſſeur ex-<lb/>traordinaire, & </s> <s xml:id="echoid-s1632" xml:space="preserve">les autres leur donnant à peine celle qu’il falloit <lb/>pour ſoûtenir le poids des Terres, a établi un Profil general ac-<lb/>commodé à toutes ſortes de hauteurs de Rempars depuis dix pieds <lb/>juſqu’à quatre-vingts; </s> <s xml:id="echoid-s1633" xml:space="preserve">& </s> <s xml:id="echoid-s1634" xml:space="preserve">quoiqu’il ſoit aſſés connu de ceux qui s’a-<lb/>pliquent aux Fortifications, il m’a parû que je ne ferois pas mal <lb/>d’en donner l’Explication telle qu’on la tient de Mr. </s> <s xml:id="echoid-s1635" xml:space="preserve">de Vauban lui-<lb/> <anchor type="note" xlink:label="note-0093-01a" xlink:href="note-0093-01"/> même, avant d’entrer dans aucun détail, afin qu’on puiſſe verifier <lb/>mes Obſervations, ſans être obligé d’aller chercher ce Profil ailleurs.</s> <s xml:id="echoid-s1636" xml:space="preserve"/> </p> <div xml:id="echoid-div127" type="float" level="2" n="1"> <note position="right" xlink:label="note-0093-01" xlink:href="note-0093-01a" xml:space="preserve">Explica-<lb/>tion qui <lb/>eſt relati-<lb/>ve au <lb/>Profil de <lb/>Mr. de <lb/>Vauban.</note> </div> <p> <s xml:id="echoid-s1637" xml:space="preserve">1<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1638" xml:space="preserve">Dans le Pays où la Maçonnerie eſt fort bonne, on peut fixer <lb/>l’épaiſſeur au ſommet à quatre pieds & </s> <s xml:id="echoid-s1639" xml:space="preserve">demi; </s> <s xml:id="echoid-s1640" xml:space="preserve">mais dans les lieux <lb/>où elle ne le ſera pas, il faudra l’augmenter juſqu’à cinq pieds ſix <lb/>pouces, & </s> <s xml:id="echoid-s1641" xml:space="preserve">même plus, ſi elle eſt fort mauvaiſe.</s> <s xml:id="echoid-s1642" xml:space="preserve"/> </p> <pb o="68" file="0094" n="96" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s1643" xml:space="preserve">2<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1644" xml:space="preserve">Que les contreforts aux angles ſaillans doivent être redou-<lb/>blés & </s> <s xml:id="echoid-s1645" xml:space="preserve">braſés de part & </s> <s xml:id="echoid-s1646" xml:space="preserve">d’autre par raport aux lignes droites qui for-<lb/> <anchor type="note" xlink:label="note-0094-01a" xlink:href="note-0094-01"/> ment ces angles.</s> <s xml:id="echoid-s1647" xml:space="preserve"/> </p> <div xml:id="echoid-div128" type="float" level="2" n="2"> <note position="left" xlink:label="note-0094-01" xlink:href="note-0094-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 12.</note> </div> <p> <s xml:id="echoid-s1648" xml:space="preserve">3<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1649" xml:space="preserve">Qu’ils ſeront toûjours élevés à plomb à l’extrémité & </s> <s xml:id="echoid-s1650" xml:space="preserve">par <lb/>les côtés, & </s> <s xml:id="echoid-s1651" xml:space="preserve">bien liés au corps de la muraille.</s> <s xml:id="echoid-s1652" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1653" xml:space="preserve">4<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1654" xml:space="preserve">Que les contreforts ſeront élevés auſſi haut que le cordon; <lb/></s> <s xml:id="echoid-s1655" xml:space="preserve">ils ſeroient encore meilleurs, ſi on leur donnoit deux pieds de plus <lb/>pour le ſoûtien du Parapet.</s> <s xml:id="echoid-s1656" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1657" xml:space="preserve">5<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1658" xml:space="preserve">Que dans les Ouvrages où le revêtement n’eſt élevé qu’à <lb/>moitié ou aux trois quarts du Rempart, & </s> <s xml:id="echoid-s1659" xml:space="preserve">le ſurplus en gaſons en <lb/>placage, il faudra régler ſon épaiſſeur comme s’il devoit être élevé <lb/>en Maçonnerie juſqu’au ſommet du rempart: </s> <s xml:id="echoid-s1660" xml:space="preserve">par exemple, ſi on <lb/>élevoit quinze pieds en gaſon au-deſſus du revêtement, il faudroit <lb/>augmenter l’épaiſſeur au ſommet de trois pieds, avec cinq qu’elle <lb/>auroit déja, pour en avoir huit à la naiſſance du gaſon.</s> <s xml:id="echoid-s1661" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1662" xml:space="preserve">6<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1663" xml:space="preserve">Qu’il faut augmenter la grandeur & </s> <s xml:id="echoid-s1664" xml:space="preserve">la ſolidité des contre-<lb/>forts à proportion de l’élevation du revêtement: </s> <s xml:id="echoid-s1665" xml:space="preserve">par exemple, ſi <lb/>le revêtement a 35 pieds de haut, ſavoir 20 en revêtement & </s> <s xml:id="echoid-s1666" xml:space="preserve">15 <lb/>en gaſon, il faudra y faire les contreforts qui ont été reglés par <lb/>le Profil de 35 pieds de haut, & </s> <s xml:id="echoid-s1667" xml:space="preserve">que le revêtement ait la même <lb/>épaiſſeur à 20 pieds de haut comme s’il en avoit 35.</s> <s xml:id="echoid-s1668" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1669" xml:space="preserve">7<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1670" xml:space="preserve">Que dans les endroits où on fera des Cavaliers comme à <lb/>Maubeuge, il faudra augmenter le ſommet du Profil d’un demi <lb/>pied d’épais pour chaque cinq pieds que le Cavalier ſera élevé au-<lb/>deſſus du revêtement, & </s> <s xml:id="echoid-s1671" xml:space="preserve">la ſolidité des contreforts à proportion: <lb/></s> <s xml:id="echoid-s1672" xml:space="preserve">ce qui doit s’entendre des gros revêtemens de la place, & </s> <s xml:id="echoid-s1673" xml:space="preserve">non pas <lb/>de ceux que l’on fait quelque fois aux Cavaliers, & </s> <s xml:id="echoid-s1674" xml:space="preserve">ſeulement quand <lb/>le pied du Cavalier aproche de trois à quatre toiſes du Parapet.</s> <s xml:id="echoid-s1675" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1676" xml:space="preserve">8<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1677" xml:space="preserve">Que les deux dernieres Colomnes de la Table portent en <lb/>toiſes, pieds, & </s> <s xml:id="echoid-s1678" xml:space="preserve">pouces cubes, ce que chaque toiſe courante de <lb/>tous ces differens Profils en contient, réduction faite des contreforts.</s> <s xml:id="echoid-s1679" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1680" xml:space="preserve">9<emph style="sub">0</emph>. </s> <s xml:id="echoid-s1681" xml:space="preserve">Que ces Profils ne ſont propoſés que pour la Maçonnerie <lb/>qui doit ſoûtenir de grands poids de Terre nouvellement remuée, <lb/>& </s> <s xml:id="echoid-s1682" xml:space="preserve">non pas celle qu’on endoſſe contre la terre vierge, qui ne l’a pas <lb/>encore été comme ſont la plûpart des revêtemens de Foſſés.</s> <s xml:id="echoid-s1683" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1684" xml:space="preserve">Mr. </s> <s xml:id="echoid-s1685" xml:space="preserve">de Vauban raporte, à la ſuite de cette Explication, une Table <lb/>compoſée de pluſieurs Colomnes, où les Dimenſions de chaque <lb/>Profil particulier qu’on voit contenuës dans la figure, ſont rapor-<lb/>tées & </s> <s xml:id="echoid-s1686" xml:space="preserve">proportionnées à ce qu’il dit, au poids des Terres qu’ils au-<lb/>ront à ſoûtenir; </s> <s xml:id="echoid-s1687" xml:space="preserve">&</s> <s xml:id="echoid-s1688" xml:space="preserve">, pour en marquer la bonté, il ajoûte qu’on l’a ex-<lb/>perimentée ſur plus de 500000 toiſes cubes de Maçonnerie baties <lb/>à 150 Places fortifiées par les ordres de Loüis le Grand.</s> <s xml:id="echoid-s1689" xml:space="preserve"/> </p> <pb o="69" file="0095" n="97" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> </div> <div xml:id="echoid-div130" type="section" level="1" n="82"> <head xml:id="echoid-head100" xml:space="preserve">TABLE</head> <head xml:id="echoid-head101" style="it" xml:space="preserve"> <emph style="bf">Pour expliquer les Dimenſious contenuës au Profil général <lb/>de Mr. de Vauban.</emph> </head> <note position="right" xml:space="preserve">Hauteur \\ des pro- \\ fils ou \\ revête- \\ mens. # Epaiſſeur \\ des re- \\ vêtemens \\ au ſom- \\ met. # Epaiſſeur \\ des re- \\ vêtemens \\ ſurla re- \\ traite. # Diſtance \\ du milieu \\ d’un con- \\ trefort à \\ l’autre. # Diſtance \\ du milieu \\ d’un con- \\ trefort à \\ l’autre. # Longueur \\ des con- \\ treforts. # Epaiſſeur \\ des con- \\ treforts à \\ la racine. # # Epaiſſeur \\ des con- \\ treforts à \\ la queuë. # # # # Solidité de la Ma- \\ çonnerie par toiſes \\ courantes, les con- \\ tréforts étant de \\ 18 pieds en 18 \\ pieds. # # # # Solidité de la Ma- \\ çonnerie par \\ toiſes courantes \\ les contreforts \\ étant de 15 \\ pieds en 15 \\ pieds. <lb/>pieds. # pieds. # pieds. # pieds. # pieds. # pieds. # pieds. # pi. # po. # pie. # pou. # lig. # poi. # pie. # pou. # lig. # poi. <lb/>10 # 5 # 7 # 18 # 15 # 4 # 3 # 2. # 0 # 2. # 0. # 11. # 1 # 2. # 1. # 1. # 4 <lb/>20 # 5 # 9 # 18 # 15 # 6 # 4 # 2. # 8 # 4. # 5. # 0. # 5 # 4. # 5. # 9. # 4 <lb/>30 # 5 # 11 # 18 # 15 # 8 # 5 # 3. # 4 # 8. # 3. # 3. # 1 # 8. # 5. # 1. # 4 <lb/>40 # 5 # 13 # 18 # 15 # 10 # 6 # 4. # 0 # 13. # 2. # 6. # 2 # 14. # 0. # 2. # 8 <lb/>50 # 5 # 15 # 18 # 15 # 12 # 7 # 4. # 8 # 19. # 3. # 8. # 10 # 20. # 4. # 2. # 8 <lb/>60 # 5 # 17 # 18 # 15 # 14 # 8 # 5. # 4 # 27. # 1. # 10. # 2 # 29. # 6. # 2. # 8 <lb/>70 # 5 # 19 # 18 # 15 # 16 # 9 # 6. # 0 # 36. # 3. # 9. # 4 # 39. # 3. # 4. # 0 <lb/>80 # 5 # 21 # 18 # 15 # 18 # 10 # 6. # 8 # 47. # 4. # 5. # 4 # 51. # 2. # 8. # 0 <lb/></note> <p> <s xml:id="echoid-s1690" xml:space="preserve">Tous les revêtemens depuis 10 pieds juſqu’à 80 ſont ſupoſés avoir <lb/>pour talud la cinquiéme partie de la hauteur, comme on en peut juger <lb/>par la figure générale: </s> <s xml:id="echoid-s1691" xml:space="preserve">quoique la plûpart des Ingenieurs trouvent ce <lb/>talud trop grand, Mr. </s> <s xml:id="echoid-s1692" xml:space="preserve">de Vauban l’a pourtant ſuivi dans toutes les <lb/>Places qu’il a fait bâtir; </s> <s xml:id="echoid-s1693" xml:space="preserve">& </s> <s xml:id="echoid-s1694" xml:space="preserve">comme il y a aparence qu’il n’ignoroit pas <lb/>les raiſons que l’on a aujourd’hui d’en donner moins, il faut croire <lb/>qu’il ne les a pas jugé aſſés fortes pour y avoir égard.</s> <s xml:id="echoid-s1695" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1696" xml:space="preserve">Pour ne pas ſe meprendre dans l’uſage de cette Table, j’ajoûte-<lb/>rai au ſujet des contreforts, que Mr. </s> <s xml:id="echoid-s1697" xml:space="preserve">de Vauban propoſe de les faire <lb/>de 18 pieds en 18 pieds, comme on le voit dans la quatriéme co-<lb/>lomne, ou bien de 15 pieds en 15 pieds, comme il eſt marqué dans <lb/>la cinquiéme; </s> <s xml:id="echoid-s1698" xml:space="preserve">c’eſt-à-dire, que ſi l’on eſtimoit que le revêtement <lb/>d’un des Profils, dont on voudroit ſe ſervir, ne fût point aſſés ſolide <lb/>pour ſoûtenir le poids des Terres, au lieu de donner 18 pieds du <lb/>milieu d’un contrefort à l’autre, on n’en donneroit que 15: </s> <s xml:id="echoid-s1699" xml:space="preserve">aparam-<lb/>ment que ſon deſſein a été qu’on en uſàt ainſi, lorſque le revêtement <pb o="70" file="0096" n="98" rhead="LA SCIENCE DES INGENIEURS,"/> auroit à ſoùtenir quelque choſe de plus que le ſempart ordinaire, <lb/>comme ſeroit, par exemple, un Cavalier ou quelque retranchement, <lb/>puiſque dans les Fortifications de Landau, du neuf-Briſac, de Béfort, <lb/>&</s> <s xml:id="echoid-s1700" xml:space="preserve">c. </s> <s xml:id="echoid-s1701" xml:space="preserve">il les a mis à la diſtance de 18 pieds: </s> <s xml:id="echoid-s1702" xml:space="preserve">mais, d’une façon comme <lb/>de l’autre, il donne toûjours les mêmes Dimenſions aux contreforts; <lb/></s> <s xml:id="echoid-s1703" xml:space="preserve">c’eſt-à-dire, que ſoit qu’on les faſſe de 15 piedsen 15 pieds, ou de <lb/>18 en 18, ils ont la même longueur & </s> <s xml:id="echoid-s1704" xml:space="preserve">la même épaiſſeur à la racine <lb/>qu’à la queuë, comme on le voit dans la Table.</s> <s xml:id="echoid-s1705" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1706" xml:space="preserve">Comme il entre plus de maçonnerie dans les revêtemens, dont <lb/>les contreforts ſont de 15 pieds en 15 pieds, que dans ceux où ils <lb/>ſont de 18 en 18, il a donné les deux dernieres colomnes de la Ta-<lb/>ble: </s> <s xml:id="echoid-s1707" xml:space="preserve">dans la penultiéme on y trouve en toiſes, pieds, & </s> <s xml:id="echoid-s1708" xml:space="preserve">pouces cu-<lb/>bes (comme il l’a dit dans le huitiéme article de ſon Explication) <lb/>la valeur d’une toiſe courante des revêtemens, y compris les con-<lb/>treforts réduits, lorſqu’ils ſont de 18 pieds en 18 pieds; </s> <s xml:id="echoid-s1709" xml:space="preserve">& </s> <s xml:id="echoid-s1710" xml:space="preserve">la derniere <lb/>eſt auſſi la valeur d’une toiſe courante des mêmes revêtemens lorſ-<lb/>qu’ils ne ſont que de 15 p. </s> <s xml:id="echoid-s1711" xml:space="preserve">en 15 p. </s> <s xml:id="echoid-s1712" xml:space="preserve">Mais on remarquera que cette <lb/>valeur de la toiſe courante, dans l’une & </s> <s xml:id="echoid-s1713" xml:space="preserve">l’autre colomne, ne doit <lb/>être comptée que pour la maçonnerie des révêtemens au-deſſus de <lb/>la retraite, parce qu’il n’y eſt pas queſtion des fondemens, à cauſe <lb/>que la difference du terrain peut les rendre plus profonds dans un <lb/>endroit que dans l’autre.</s> <s xml:id="echoid-s1714" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1715" xml:space="preserve">On remarquera encore, que ſelon ce qui eſt raporté dans la ſep-<lb/>tiéme & </s> <s xml:id="echoid-s1716" xml:space="preserve">huitiéme colomne, auſſi-bien qu’au Profil général, tous les <lb/>contreforts ſont plus épais à la racine qu’à la queuë, & </s> <s xml:id="echoid-s1717" xml:space="preserve">que cette <lb/>épaiſſeur de la queuë eſt les deux tiers de celle de la racine, la-<lb/>quelle va toûjours en augmentant d’un pied à meſure que la hau-<lb/>teur des revêtemens augmente de 10, & </s> <s xml:id="echoid-s1718" xml:space="preserve">que la longueur des mê-<lb/>mes contreforts augmente de deux pieds en ſuivant encore la pro-<lb/>portion des hauteurs.</s> <s xml:id="echoid-s1719" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1720" xml:space="preserve">Aux contreforts dont j’ai parlé dans l’art. </s> <s xml:id="echoid-s1721" xml:space="preserve">50. </s> <s xml:id="echoid-s1722" xml:space="preserve">j’ai ſupoſé que la <lb/>racine GK, étoit double de la queuë HI, parce que voulant les diſ-<lb/>poſer dans un ſens contraire, comme au contrefort CF, pour les <lb/> <anchor type="note" xlink:label="note-0096-01a" xlink:href="note-0096-01"/> raiſons que j’en ai donné, il ma parû qu’il valoit mieux faire la li-<lb/>gne EF, moitié de CD, que ſi elle en étoit les deux tiers, à cauſe <lb/>que ſelon l’art. </s> <s xml:id="echoid-s1723" xml:space="preserve">50. </s> <s xml:id="echoid-s1724" xml:space="preserve">plus la queuë des contreforts ſera au-deſſus de <lb/>la racine, plus le revêtement aura de force; </s> <s xml:id="echoid-s1725" xml:space="preserve">c’eſt pourquoi je n’ai <lb/>point ſuivi la pratique de Mr. </s> <s xml:id="echoid-s1726" xml:space="preserve">de Vauban.</s> <s xml:id="echoid-s1727" xml:space="preserve"/> </p> <div xml:id="echoid-div130" type="float" level="2" n="1"> <note position="left" xlink:label="note-0096-01" xlink:href="note-0096-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 9.</note> </div> <p> <s xml:id="echoid-s1728" xml:space="preserve">Si l’on prend garde à la ſeconde colomne de la Table, l’on verra <lb/>que les revêtemens, à quelque hauteur qu’on veüille les faire, doi-<lb/>vent toûjours avoir cinq pieds au ſommet, ainſi ils ne ſont aug- <pb o="71" file="0097" n="99" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> mentés en épaiſſeur que ſur la retraite, de la quantité dont la ligne <lb/>de talud devient plus grande à meſure que l’élevation eſt plus con-<lb/>ſiderable, ce qui ne rendroit pas ces revêtemeus proportionnés à <lb/>la pouſſée qu’ils ont à ſoûtenir, ſi ce défaut n’étoit reparé en par-<lb/>tie par l’augmentation qu’on doit faire aux contreforts, ſelon ce <lb/>qui eſt dit dans le ſixiéme article de l’explication. </s> <s xml:id="echoid-s1729" xml:space="preserve">Mais, voilà <lb/>le Profil général ſuffiſamment détaillé, paſſons au Paralelle que je <lb/>me ſuis propoſé.</s> <s xml:id="echoid-s1730" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1731" xml:space="preserve">Quand on eſt accoûtumé d’agir ſelon les principes des Mathé-<lb/>matiques, on ſe fait aiſément des difficultés: </s> <s xml:id="echoid-s1732" xml:space="preserve">à moins que l’éviden-<lb/>ce ne régne dans tout ce que l’on nous donne pour juſte, l’eſprit <lb/>n’eſt point ſatisfait; </s> <s xml:id="echoid-s1733" xml:space="preserve">& </s> <s xml:id="echoid-s1734" xml:space="preserve">ce qui paroît indubitable aux yeux de tout <lb/>le monde, donne ſouvent de grands ſujets d’inquiétude aux Géo-<lb/>mêtres. </s> <s xml:id="echoid-s1735" xml:space="preserve">J’ai été long-tems dans cette diſpoſition à l’occaſion du Pro-<lb/>fil général de Mr. </s> <s xml:id="echoid-s1736" xml:space="preserve">de Vauban: </s> <s xml:id="echoid-s1737" xml:space="preserve">ce Profil, me ſuis-je dit pluſieurs fois, <lb/>doit être bon, puiſque l’on s’en eſt toûjours ſervi avec ſuccès. <lb/></s> <s xml:id="echoid-s1738" xml:space="preserve">Cela vient-il de ce que les revêtemens qu’on y propoſe ſont en équi-<lb/>libre avec la pouſſée des Terres? </s> <s xml:id="echoid-s1739" xml:space="preserve">Ou ſeroit-ce à cauſe qu’ils ſont <lb/>tellement au-deſſus de cette pouſſée, qu’il ne peut jamais leur arri-<lb/>ver d’être renverſés? </s> <s xml:id="echoid-s1740" xml:space="preserve">Si ç’en eſt-là la raiſon, on employe peut-être <lb/>ſans le ſavoir une grande quantité de maçonnerie ſuperfluë: </s> <s xml:id="echoid-s1741" xml:space="preserve">ſi au <lb/>contraire ils n’ont que les dimenſions qui leur conviennent pour <lb/>être un peu au-deſſus de la pouſſée des Terres, on ne peut pas <lb/>s’hazarder à élever ſur un Rempart, comme on le fait quelquefois, <lb/>des Cavaliers, des retranchemens, ou quelque autre Ouvrage, pour <lb/>ſe couvrir contre les commandemens, parce que le revêtement, ſe <lb/>trouvant trop foible pour ſoûtenir cette nouvelle charge, pourroit <lb/>culbuter dans le Foſſé, comme cela n’eſt pas ſans exemple. </s> <s xml:id="echoid-s1742" xml:space="preserve">Ces <lb/>réfléxions me faiſoient ſentir qu’il falloit ſavoir calculer la pouſſée <lb/>des Terres pour y proportionner les revêtemens quand on vouloit <lb/>les conſtruire, ou bien pour ſavoir de quelle force ils étoient capa-<lb/>bles après qu’étant une fois conſtruits, on vouloit augmenter la <lb/>charge. </s> <s xml:id="echoid-s1743" xml:space="preserve">Or, comme c’eſt-là ce que nous nous propoſons d’exami-<lb/>ner ici, nous nous atacherons aux ſix premiers revêtements du Pro-<lb/>fil général, parce qu’il y a aparence qu’il en ſera des autres qui les <lb/>ſuivent comme de ceux-ci, & </s> <s xml:id="echoid-s1744" xml:space="preserve">nous commencerons par chercher <lb/>quelle eſt la puiſſance avec laquelle chacun d’eux doit être en équi-<lb/>libre, en leur ſupoſant les mêmes dimenſions qui leur répondent <lb/>dans la Table.</s> <s xml:id="echoid-s1745" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1746" xml:space="preserve">Faiſant abſtraction de la petite muraille CN, à laquelle nous <lb/> <anchor type="note" xlink:label="note-0097-01a" xlink:href="note-0097-01"/> n’aurons point égard, parce qu’elle eſt toûjours la même dans cha- <pb o="72" file="0098" n="100" rhead="LA SCIENCE DES INGENIEURS,"/> que Profil, & </s> <s xml:id="echoid-s1747" xml:space="preserve">que d’ailleurs elle n’eſt plus guére d’uſage, nous <lb/>nommerons l’épaiſſeur AC, ou BD, a; </s> <s xml:id="echoid-s1748" xml:space="preserve">la hauteur CD, c; </s> <s xml:id="echoid-s1749" xml:space="preserve">la ligne <lb/>de talud DE, d; </s> <s xml:id="echoid-s1750" xml:space="preserve">la longueur GB des contreforts h; </s> <s xml:id="echoid-s1751" xml:space="preserve">la diſtance <lb/>KE, du centre de gravité des contreforts au point d’apui, n; </s> <s xml:id="echoid-s1752" xml:space="preserve">& </s> <s xml:id="echoid-s1753" xml:space="preserve">le <lb/>raport de l’eſpace qu’occupe chaque contrefort à l’intervalle où <lb/>ils ſont du milieu de l’un au milieu de l’autre, ſera exprimé <lb/>par {p/q}.</s> <s xml:id="echoid-s1754" xml:space="preserve"/> </p> <div xml:id="echoid-div131" type="float" level="2" n="2"> <note position="right" xlink:label="note-0097-01" xlink:href="note-0097-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 13.</note> </div> <p> <s xml:id="echoid-s1755" xml:space="preserve">Cela poſé, ſi l’on multiplie ch par {p/q} l’on aura {pch/q} pour la <lb/>valeur des contreforts réduite, laquelle étant multipliée par le bras <lb/>de lévier EK, (n) il viendra {pchn/q}; </s> <s xml:id="echoid-s1756" xml:space="preserve">multipliant de mêmele poids <lb/>R, ({dc/2}) par ſon bras de lévier ME, ({2d/3}) & </s> <s xml:id="echoid-s1757" xml:space="preserve">le poids Q, (ac) <lb/>par le ſien LE; </s> <s xml:id="echoid-s1758" xml:space="preserve">ajoûtant ces trois produits enſemble, l’on aura <lb/>{pchn/q} + {2acd + aac/2} + {cdd/3}, pour la valeur des poids P, Q, R, réünis <lb/>au point L, & </s> <s xml:id="echoid-s1759" xml:space="preserve">multipliée par le bras de lévier LE, ſelon l’art. </s> <s xml:id="echoid-s1760" xml:space="preserve">22. <lb/></s> <s xml:id="echoid-s1761" xml:space="preserve">égale au produit du bras de lévier AB, ou ES, par la puiſſance <lb/>que l’on cherche, laquelle étant nommée x, donne, en effaçant c, <lb/>{phn/q} + {2ad + aa/2} + {dd/3} = x, qui eſt une équation générale qui <lb/>conviendra à tel Profil de revêtement que l’on voudra, puiſqu’il <lb/>ne faudra avoir égard qu’à la valeur des lettres.</s> <s xml:id="echoid-s1762" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1763" xml:space="preserve">Voulant apliquer cette équation à un revêtement de 20 pieds <lb/>de hauteur, on aura recours à la Table de Mr. </s> <s xml:id="echoid-s1764" xml:space="preserve">de Vauban, pour <lb/>voir les meſures qui lui apartiennent, & </s> <s xml:id="echoid-s1765" xml:space="preserve">l’on trouvera que d=4, <lb/>a=5, h=6, n=11 pieds, 9 pouces, 6 lignes, comme l’épaiſ-<lb/>ſeur des contreforts eſt les deux tiers de celle de la racine, & </s> <s xml:id="echoid-s1766" xml:space="preserve">que <lb/>par conſéquent ces contreforts ont leur baſes trapezoïdes: </s> <s xml:id="echoid-s1767" xml:space="preserve">remar-<lb/>qués que prenant le Profil GC, pour celui ſur lequel nous opérons <lb/>preſentement, la ligne BG, ſelon l’art. </s> <s xml:id="echoid-s1768" xml:space="preserve">10. </s> <s xml:id="echoid-s1769" xml:space="preserve">doit être diviſée entrois <lb/>parties égales, & </s> <s xml:id="echoid-s1770" xml:space="preserve">celle du milieu HI, coupée de façon au point K, <lb/>pour avoir le centre de gravité, que KI, ſoit à KH: </s> <s xml:id="echoid-s1771" xml:space="preserve">dans la rai-<lb/>ſon de l’épaiſſeur de la queuë à celle de la racine, j’entends comme <lb/>2 eſt à 3, ainſi KI, ſera les {2/5} de HI, ou IB, mais comme la <lb/>toute GB, vaut 6, HI, ou IB, ne vaudra que 2, à quoi ajoûtant les <lb/>{2/5} du même IB, l’on aura 2 pieds, 9 pouces, 6 lignes pour la <lb/>valeur de KB, qui étant jointe à BE, (a + d) l’on aura 11 pieds, <pb o="73" file="0099" n="101" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> 9 pouces 6 lignes pour la valeur de n; </s> <s xml:id="echoid-s1772" xml:space="preserve">pour ſavoir auſſi ce que <lb/>doit valoir {p/q}, conſiderés que p, doit marquer l’épaiſſeur de cha-<lb/>que contrefort, & </s> <s xml:id="echoid-s1773" xml:space="preserve">q, l’intervalle de leur milieu: </s> <s xml:id="echoid-s1774" xml:space="preserve">ajoûtant donc les <lb/>dimenſions de la racine avec celles de la queuë, telles qu’on les <lb/>trouve dans la Table, je veux dire 4 pieds, avec 2 pieds 8 pouces, <lb/>l’on aura 6 pieds 8 pouces, dont la moitié qui eſt 3 pieds 4 pou-<lb/>ces, ſera l’épaiſſeur moyenne des contreforts, par conſéquent la <lb/>valeur de p; </s> <s xml:id="echoid-s1775" xml:space="preserve">quant à celle de q, elle ſera toûjours 18, parce que <lb/>c’eſt la diſtance du milieu d’un contrefort à l’autre, ainſi {p/q} ſera <lb/>la même choſe que {40/216} ou bien {5/27;</s> <s xml:id="echoid-s1776" xml:space="preserve">} multipliant cette quantité par <lb/>la valeur de nh, l’on trouvera 12 pieds 5 pouces pour {phn/q}, l’on <lb/>trouvera auſſi que {2ad + aa/2} vaut 32 pieds 6 pouces, & </s> <s xml:id="echoid-s1777" xml:space="preserve">{dd/3}5 pi. <lb/></s> <s xml:id="echoid-s1778" xml:space="preserve">4 pouces.</s> <s xml:id="echoid-s1779" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1780" xml:space="preserve">Joignant donc tous ces nombres enſemble, il viendra 50 pieds <lb/>4 pouces 10 lignes pour la valeur de x; </s> <s xml:id="echoid-s1781" xml:space="preserve">c’eſt-à-dire, pour la puiſ-<lb/>ſance avec laquelle le revêtement de 20 pieds du Profil général <lb/>peut être en équilibre; </s> <s xml:id="echoid-s1782" xml:space="preserve">c’eſt en faiſant les mêmes calculs avec toute <lb/>la préciſion imaginable, que j’ai trouvé que le revêtement de 10 <lb/>pieds de hauteur étoit en équilibre avec une puiſſance de 28 pieds <lb/>10 pouces; </s> <s xml:id="echoid-s1783" xml:space="preserve">celui de 20, avec 50 pieds 4 pouces 10 lignes; </s> <s xml:id="echoid-s1784" xml:space="preserve">ce-<lb/>lui de 30, avec 81 pieds un pouce; </s> <s xml:id="echoid-s1785" xml:space="preserve">celui de 40, avec 123 pieds <lb/>10 pouces; </s> <s xml:id="echoid-s1786" xml:space="preserve">celui de 50, avec 175 pieds 10 pouces; </s> <s xml:id="echoid-s1787" xml:space="preserve">enfin celui <lb/>de 60, avec 237 pieds, 7 pouces.</s> <s xml:id="echoid-s1788" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1789" xml:space="preserve">Pour ſavoir préſentement le raport de la réſiſtance de chacun de <lb/>ces revêtemens avec les puiſſances qui exprimeroient la pouſſée <lb/>des Terres qu’ils ont à ſoûtenir, il faut chercher la valeur de ces <lb/>puiſſances pour 10, 20, 30, 40, 50, & </s> <s xml:id="echoid-s1790" xml:space="preserve">60 pieds de hauteur dans <lb/>la troiſiéme colomne de la Table que nous avons donnée art. </s> <s xml:id="echoid-s1791" xml:space="preserve">37. <lb/></s> <s xml:id="echoid-s1792" xml:space="preserve">& </s> <s xml:id="echoid-s1793" xml:space="preserve">l’on trouvera qu’elles ſont équivalentes à 15 pieds 7 pouces; </s> <s xml:id="echoid-s1794" xml:space="preserve"><lb/>41 pieds 5 pouces; </s> <s xml:id="echoid-s1795" xml:space="preserve">75 pieds 4 pouces; </s> <s xml:id="echoid-s1796" xml:space="preserve">117 pieds 8 pouces; </s> <s xml:id="echoid-s1797" xml:space="preserve"><lb/>170 pieds un pouce & </s> <s xml:id="echoid-s1798" xml:space="preserve">à 233, qui étant comparés avec la réſiſtan-<lb/>ce des revêtemens, l’on aura {15/28}, {41/51}, {75/82}, {117/124}, {170/176}, {233/237}, ou à <lb/>peu-près {1/2}, {1/4}, {1/8}, {1/19}, {1/29}, {1/58}, ce qui fait voir que le revê-<lb/>tement de 10 pieds ſelon le Profil général eſt en état de ſoutenir une <lb/>pouſſée double de celle qu’il ſoûtient naturellement; </s> <s xml:id="echoid-s1799" xml:space="preserve">que celui de <pb o="74" file="0100" n="102" rhead="LA SCIENCE DES INGENIEURS,"/> 20, eſt au-deſſus de l’équilibre d’un quart de la réſiſtance qu’il lui <lb/>faut; </s> <s xml:id="echoid-s1800" xml:space="preserve">celui de 30, n’eſt au-deſſus de l’équilibre que d’un huitiéme; <lb/></s> <s xml:id="echoid-s1801" xml:space="preserve">celui de 40, d’un dix-neuviéme; </s> <s xml:id="echoid-s1802" xml:space="preserve">celui de 50, d’un vingt-uniéme; </s> <s xml:id="echoid-s1803" xml:space="preserve"><lb/>& </s> <s xml:id="echoid-s1804" xml:space="preserve">celui de 60, d’un cinquante-huitiéme.</s> <s xml:id="echoid-s1805" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1806" xml:space="preserve">Comme les raports précédens ont été trouvés par des régles <lb/>inconteſtables, on ne peut donc douter que, dans le Profil géné-<lb/>ral, la réſiſtance des revêtemens ne diminuë à proportion qu’ils <lb/>ont plus d’élevation, puiſque tandis que celui de 10 pieds eſt au-<lb/>deſſus del’équilibre de toute la pouſſée qu’il devroit ſoûtenir natu-<lb/>rellement, celui de ſoixante n’a ſa réſiſtance que d’un cinquante-<lb/>huitiéme au-deſſus de l’équilibre, qui étant une difference fort pe-<lb/>tite, on peut regarder ce revêtement comme en équilibre avec la <lb/>pouſſée des Terres; </s> <s xml:id="echoid-s1807" xml:space="preserve">ainſi dans ceux qui ſont plus élevés, il eſt à <lb/>préſumer que ſuivant les proportions du Profil général, la pouſſée <lb/>deviendra au-deſſus de la réſiſtance: </s> <s xml:id="echoid-s1808" xml:space="preserve">au lieu qu’il faudroit que le <lb/>revêtement fût toûjours capable de réſiſter avec une force plus <lb/>grande que la pouſſée, afin de n’avoir rien à craindre des accidens <lb/>qui peuvent arriver, ſoit de la part des grandes pluyes, qui au bout <lb/>d’un certain tems peuvent augmenter conſidérablement le poids <lb/>des terres, ſoit par les ébranlemens qui arrivent quelquefois par le <lb/>bruit du Tonnerre, ou du Canon qu’on tire ſur les Rempars, qui <lb/>pourroient produire des ſecouſſes capables de cauſer le renverſe-<lb/>ment de quelque face d’ouvrages. </s> <s xml:id="echoid-s1809" xml:space="preserve">D’ailleurs, quand mêmetous ces <lb/>mouvemens ne ſurviendroient point, il y a encore une raiſon pour <lb/>mettre les revêtemens beaucoup au-deſſus de la pouſſée; </s> <s xml:id="echoid-s1810" xml:space="preserve">c’eſt qu’en <lb/>tems de ſiége, quand un ouvrage eſt battu en bréche, la violence <lb/>du Canon ne peut manquer de cauſer un grand mouvement dans <lb/>les parties de la maçonnerie & </s> <s xml:id="echoid-s1811" xml:space="preserve">dans les terres, qui pourroit préci-<lb/>piter l’avancement de la brêche, parce que le revêtement ſe trou-<lb/>vant au-deſſous de la pouſſée, comme je le ſupoſe, il auroit plus <lb/>de penchant à culbuter: </s> <s xml:id="echoid-s1812" xml:space="preserve">on me dira peut-être, que c’eſt vouloir <lb/>examiner les choſes trop phyſiquement; </s> <s xml:id="echoid-s1813" xml:space="preserve">mais, dansun ſujet comme <lb/>celui-ci, il faut avoir égard à tout.</s> <s xml:id="echoid-s1814" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1815" xml:space="preserve">On fera encore attention que ſi au lieu de donner cinq pieds <lb/>d’épaiſſeur au ſommet, on n’en donnoit que quatre & </s> <s xml:id="echoid-s1816" xml:space="preserve">demi dans <lb/>les endroits où la maçonnerie ſeroit fort bonne, comme il eſt dit <lb/>dans le premier article del’Explication de Mr. </s> <s xml:id="echoid-s1817" xml:space="preserve">de Vauban, ceſeroit <lb/>alors qu’on auroit tout à craindre du peu de réſiſtance des revê-<lb/>temens de 40, 50, 60, & </s> <s xml:id="echoid-s1818" xml:space="preserve">70 pieds de hauteur, puiſqu’elle ſe trou-<lb/>veroit au-deſſous de la pouſſée des terres: </s> <s xml:id="echoid-s1819" xml:space="preserve">car, comme je l’ai dit, <lb/>article 13, la liaiſon doit être ſupoſée ici la meilleure qu’il eſt poſ- <pb o="75" file="0101" n="103" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> ſible, & </s> <s xml:id="echoid-s1820" xml:space="preserve">on ne doit avoir égard qu’au poids & </s> <s xml:id="echoid-s1821" xml:space="preserve">à la longueur du bras <lb/>de lévier qui répond à la baſe du mur; </s> <s xml:id="echoid-s1822" xml:space="preserve">ce qui feroit croire que Mr. <lb/></s> <s xml:id="echoid-s1823" xml:space="preserve">de Vauban n’a pas eû cette conſideration.</s> <s xml:id="echoid-s1824" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1825" xml:space="preserve">Malgré ce que je viens de dire, je ne regarde pas le Proſil gé-<lb/>néral aſſés défectueux pour ne pouvoir pas s’en ſervir; </s> <s xml:id="echoid-s1826" xml:space="preserve">l’expe-<lb/>rience, qui prouve le contraire, ne ſeroit pas de mon côté: </s> <s xml:id="echoid-s1827" xml:space="preserve">je vou-<lb/>drois ſeulement qu’on ne donnât pas tant d’épaiſſeur au ſommet <lb/>des petits revêtemens, & </s> <s xml:id="echoid-s1828" xml:space="preserve">que pour plus de ſûreté on en donnât <lb/>davantage à celui des plus élevés; </s> <s xml:id="echoid-s1829" xml:space="preserve">car, je ne vois pas la néceſſité <lb/>de donner cinq pieds au ſommet de celui qui n’en auroit que dix <lb/>en hauteur, comme s’il en avoit quatre-vingt, puiſque, ſi l’on y fait <lb/>attention, c’eſt juſtement de-là que vient le défaut du Profil géné-<lb/>ral; </s> <s xml:id="echoid-s1830" xml:space="preserve">car comme il faut que les proportions de toutes les parties <lb/>de chaque revêtement augmentent ou diminuent dans la même <lb/>raiſon, ſelon que l’élevation eſt plus grande ou plus petite, afin <lb/>que la réſiſtance ſoit toûjours proportionnée à la pouſſée, il n’y a <lb/>point de doute que ſi une des dimenſions du Profil demeure conſ-<lb/> <anchor type="note" xlink:label="note-0101-01a" xlink:href="note-0101-01"/> tante comme eſt ici celle du ſommet, la pouſſée des terres ne ſoit <lb/>au-deſſous de la réſiſtance des petits revêtemens, & </s> <s xml:id="echoid-s1831" xml:space="preserve">ne devienne au-<lb/>deſſus de celle des plus grands: </s> <s xml:id="echoid-s1832" xml:space="preserve">il faut donc que le bras de lévier <lb/> <anchor type="note" xlink:label="note-0101-02a" xlink:href="note-0101-02"/> LE, augmente dans la raiſon de la hauteur AB, pour que la pro-<lb/>portion ne ſoit point interrompuë, au lieu qu’elle ne peut man-<lb/>quer de l’être, tant que les lignes BD, AC, demeureront toûjours <lb/>de cinq pieds, & </s> <s xml:id="echoid-s1833" xml:space="preserve">que les trois autres AB, BG, DE, augmente-<lb/>ront ou diminuëront.</s> <s xml:id="echoid-s1834" xml:space="preserve"/> </p> <div xml:id="echoid-div132" type="float" level="2" n="3"> <note position="right" xlink:label="note-0101-01" xlink:href="note-0101-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 12.</note> <note position="right" xlink:label="note-0101-02" xlink:href="note-0101-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 18.</note> </div> <p> <s xml:id="echoid-s1835" xml:space="preserve">Or pour ſavoir de combien il faudroit augmenter l’épaiſſeur du <lb/>ſommet des grands revêtemens, & </s> <s xml:id="echoid-s1836" xml:space="preserve">diminuer celle des petits pour <lb/>les bien proportionner à la pouſſée des terres & </s> <s xml:id="echoid-s1837" xml:space="preserve">rendre régulier le <lb/>Profil général, nous prendrons pour exemple celui de la figure 13. <lb/></s> <s xml:id="echoid-s1838" xml:space="preserve">& </s> <s xml:id="echoid-s1839" xml:space="preserve">nous nommerons GB, h; </s> <s xml:id="echoid-s1840" xml:space="preserve">KB, g; </s> <s xml:id="echoid-s1841" xml:space="preserve">BD, y; </s> <s xml:id="echoid-s1842" xml:space="preserve">l’on aura g + y + d, <lb/>& </s> <s xml:id="echoid-s1843" xml:space="preserve">{pch/q} ſera la valeur des contreforts réünie autour du centre <lb/>de gravité CK, qui étant multipliée par le bras de lévier KE, don-<lb/>nera {pchg + pchy + pchd/q} pour le produit. </s> <s xml:id="echoid-s1844" xml:space="preserve">De même, ſi l’on multiplie <lb/>le poids Q (yc) par LE, ({y/2} + d) & </s> <s xml:id="echoid-s1845" xml:space="preserve">le poids R ({dc/2}) par ME <lb/>({2d/3}), joignant ces trois produits enſemble, la ſomme ſera égale <lb/>au produit de la puiſſance hf, par ſon bras de lévier; </s> <s xml:id="echoid-s1846" xml:space="preserve">ce qui donne, <lb/>en effaçant c de part & </s> <s xml:id="echoid-s1847" xml:space="preserve">d’autre, {phg + phy + phd/q} + {yy/2} + yd + {dd/3} <pb o="76" file="0102" n="104" rhead="LA SCIENCE DES INGENIEURS,"/> = bf. </s> <s xml:id="echoid-s1848" xml:space="preserve">Or ſi l’on ſupoſe ny = {phy/q} + dy, & </s> <s xml:id="echoid-s1849" xml:space="preserve"><lb/>mettant ny, à la place de ſa valeur dans l’équation précédente, l’on <lb/>aura {phg + phd/q} + {dd/3} +{yy/2} + ny=bf, d’où faiſant paſſer du pre-<lb/>mier membre dans le ſecond les termes, où y ne ſe trouve point, <lb/>& </s> <s xml:id="echoid-s1850" xml:space="preserve">multipliant le tout par 2, il vient yy + 2ny = 2bf - {2dd/3} <lb/>- {2phg - 2phd/q}, ou yy + 2ny + nn = 2bf - {2dd/3} - {2phg - 2phd/q} <lb/>+ nn, en ajoûtant nn de part & </s> <s xml:id="echoid-s1851" xml:space="preserve">d’autre qui donne <lb/>y = √2bf - {2dd/3} - {2phg - 2phd/q} + nn\x{0020} - n, qui eſt une équa-<lb/>tion qui conviendra à tel revêtement que l’on voudra du Profil <lb/>general, puiſqu’il n’y aura que la valeur des lettres qui en fera la <lb/>différence.</s> <s xml:id="echoid-s1852" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1853" xml:space="preserve">Nous ſervant de cette équation pour ſavoir quelle épaiſſeur il <lb/>faut donner au ſommet d’un revêtement de 40 pieds de hauteur, <lb/>tiré du Profil general, afin que ce revêtement ſoit au-deſſus de la <lb/>pouſſée des terres, de telle quantité que l’on voudra, par exemple <lb/>d’un ſixiéme de la même pouſſée, qui doit ſuffire comme j’en ferai <lb/>voir la raiſon dans la ſuite; </s> <s xml:id="echoid-s1854" xml:space="preserve">il faut chercher dans la troiſiéme co-<lb/>lomne des puiſſances, quelle eſt la valeur de celle qui exprime la <lb/>pouſſée des terres du Parapet & </s> <s xml:id="echoid-s1855" xml:space="preserve">du Rempart de 40 pieds, l’on trou-<lb/>vera qu’elle eſt de 117 pieds 8 pouces, dont il faut prendre le ſixié-<lb/>me qui eſt 19 pieds 7 pouces 4 lignes, qui étant ajoûtés avec la <lb/>valeur de la puiſſance même, l’on aura 137 pieds 3 pouces 4 lignes <lb/>pour la valeur de bf, qui étant multipliée par 2, afin de ſuivre ce <lb/>qui eſt marqué dans l’équation, il vient 274 pieds 6 pouces 8 lignes <lb/>pour 2bf; </s> <s xml:id="echoid-s1856" xml:space="preserve">& </s> <s xml:id="echoid-s1857" xml:space="preserve">pour avoir de ſuite la valeur des quantités poſitives, <lb/>remarqués que les contreforts pour 40 pieds dans la Table du Profil <lb/>general, ont ſix pieds de racine & </s> <s xml:id="echoid-s1858" xml:space="preserve">quatre de queuë, & </s> <s xml:id="echoid-s1859" xml:space="preserve">que par con-<lb/>ſéquent l’épaiſſeur moyenne eſt cinq, qui eſt la valeur P, com-<lb/>me la diſtance du milieu d’un contrefort à l’autre eſt toûjours 18 <lb/>pieds; </s> <s xml:id="echoid-s1860" xml:space="preserve">l’on aura donc dans ce cas-là {p/q} = {5/18}: </s> <s xml:id="echoid-s1861" xml:space="preserve">& </s> <s xml:id="echoid-s1862" xml:space="preserve">comme nous <lb/>avons n = {ph/q} + d, n, vaudra donc 10 pieds 9 pouces 4 lignes, dont <lb/>le quarré eſt 116 pieds un pouce 11 lignes, qui étant ajoûtés avec <lb/>la valeur de 2bf, donnent 390 pieds 8 pouces 7 lignes pour les <lb/>deux grandeurs poſitives 2bf + nn; </s> <s xml:id="echoid-s1863" xml:space="preserve">& </s> <s xml:id="echoid-s1864" xml:space="preserve">cherchant la valeur des né- <pb file="0103" n="105"/> <pb file="0103a" n="106"/> <anchor type="figure" xlink:label="fig-0103a-01a" xlink:href="fig-0103a-01"/> <pb file="0104" n="107"/> <pb o="77" file="0105" n="108" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> gatives - {2dd/3} - {2phg - 2phg/q}, on trouvera que leur ſomme eſt <lb/>113 pieds 4 lignes, qui étant retranchée du nombre précédent, la <lb/>différence eſt 277 pieds 8 pouces 3 lignes, dont la racine quarrée <lb/>eſt 16 pieds 8 pouces 9 lignes, d’où il faut retrancher la valeur <lb/>de n, c’eſt-à-dire, 10 pieds 9 pouces 4 lignes, il reſtera 5 pieds <lb/>11 pouces 5 lignes, qui eſt l’épaiſſeur qu’il faut donner au ſommet <lb/>du revêtement de 40 pieds du Profil general, pour que ſa réſiſtance <lb/>ſoit au-deſſus de la pouſſee des terres de la ſixiéme partie de la for-<lb/>ce de cette pouſſée.</s> <s xml:id="echoid-s1865" xml:space="preserve"/> </p> <div xml:id="echoid-div133" type="float" level="2" n="4"> <figure xlink:label="fig-0103a-01" xlink:href="fig-0103a-01a"> <image file="0103a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0103a-01"/> </figure> </div> <p> <s xml:id="echoid-s1866" xml:space="preserve">C’eſt en faiſant les mêmes opérations rélativement à la valeur des <lb/>termes de la formule générale, qu’on trouvera que l’épaiſſeur au <lb/>ſommet pour le revêtement de dix pieds, doit être de 3 pieds 5 <lb/>pouces 4 lignes; </s> <s xml:id="echoid-s1867" xml:space="preserve">pour celui de 20, de 4 pieds 8 pouces 9 lignes; <lb/></s> <s xml:id="echoid-s1868" xml:space="preserve">pour celui de 30, de 5 pieds 5 pouces 9 lignes; </s> <s xml:id="echoid-s1869" xml:space="preserve">pour celui de <lb/>50, de 6 pieds 2 pouces 10 lignes; </s> <s xml:id="echoid-s1870" xml:space="preserve">& </s> <s xml:id="echoid-s1871" xml:space="preserve">pour celui de 60, de 6 <lb/>pieds 8 pouces 10 lignes.</s> <s xml:id="echoid-s1872" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1873" xml:space="preserve">Convaincu, comme je viens de le prouver, que la plûpart des <lb/>revêtemens du Profil géneral n’étoient pas capables de toute la <lb/>réſiſtance qui paroît leur être neceſſaire pour ſoûtenir la pouſſée <lb/>des terres & </s> <s xml:id="echoid-s1874" xml:space="preserve">tous les ébranlemens qui peuvent ſurvenir, on ſera ſans <lb/>doute ſurpris que tous ceux que l’on a conſtruits ſe ſoûtiennent en <lb/>bon état depuis long-tems, ſans qu’il leur ſoit arrivé aucun acci-<lb/>dent: </s> <s xml:id="echoid-s1875" xml:space="preserve">ce qui ſemble détruire mes raiſonnemens, tout démontrés <lb/>qu’ils ſoient. </s> <s xml:id="echoid-s1876" xml:space="preserve">Cependant l’on verra que cela ne peut guéres arriver <lb/>autrement, ſi l’on fait attention que trois raiſons en ſont la cauſe; <lb/></s> <s xml:id="echoid-s1877" xml:space="preserve">la premiere, c’eſt que les revêtemens que l’on fait d’ordinaire aux <lb/>Fortifications paſſent rarement 35 à 40 pieds, & </s> <s xml:id="echoid-s1878" xml:space="preserve">qu’à cette hauteur <lb/>la réſiſtance ne laiſſe pas d’être encore beaucoup au-deſſus de la <lb/>pouſſée, comme nous le venons de voir; </s> <s xml:id="echoid-s1879" xml:space="preserve">la ſeconde, que les terres <lb/>n’ont jamais toute la pouſſée dont elles ſont capables, parce que <lb/>quand on éleve les Rempars, on les entretient avec des lits de faſ-<lb/>cinage, qui font qu’elles ſe ſoûtiennent preſque d’elles-mêmes; </s> <s xml:id="echoid-s1880" xml:space="preserve">la <lb/>troiſiéme, c’eſt que le pied du revêtement eſt bien lié avec les fon-<lb/>demens, leſquels étant enterrés ne peuvent pas facilement incliner <lb/>du côté du Foſſé, quand même la réſiſtance du revêtement ſeroit <lb/>au-deſſous de l’équilibre: </s> <s xml:id="echoid-s1881" xml:space="preserve">joignons à cela, que le ſommet des contre-<lb/>forts étant couvert par cinq ou ſix pieds de terres qui compoſent le <lb/>Parapet, ces terres font l’effet d’une puiſſance qui contre-balance <lb/>en partie l’effort de pluſieurs autres puiſſances qui agiroient pour <lb/>renverſer le revêtement; </s> <s xml:id="echoid-s1882" xml:space="preserve">c’eſt pourquoi j’ai dit ci-devant, qu’il ſuf- <pb o="78" file="0106" n="109" rhead="LA SCIENCE DES INGENIEURS,"/> firoit de rendre les revêtemens capables de ſoûtenir une pouſſée <lb/>qui ne fut que de la ſixiéme partie audeſſus de celle que cauſent <lb/>naturellement les terres qui ſont élevées derriere; </s> <s xml:id="echoid-s1883" xml:space="preserve">car enfin les ter-<lb/>res du Parapet agiront d’autant plus puiſſamment ſur les contreforts <lb/>pour les retenir, que ces contreforts ſeront plus longs: </s> <s xml:id="echoid-s1884" xml:space="preserve">ainſi plus les <lb/>revêtemens ſeront élevés, & </s> <s xml:id="echoid-s1885" xml:space="preserve">plus dans ce ſens ils trouveront d’obſ-<lb/>tacles à incliner; </s> <s xml:id="echoid-s1886" xml:space="preserve">il n’y a que dans le cas où les terres du Parapet <lb/>ſeroient éboulées quand on bat en brêche, où il y auroit quelque <lb/>choſe à craindre, parce que le deſſus des contreforts n’étant plus <lb/>retenu, le revêtement pourroit culbuter ſi la réſiſtance étoit au-<lb/>deſſous de l’équilibre: </s> <s xml:id="echoid-s1887" xml:space="preserve">quand je dis que cela pourroit arriver ici, <lb/>ſi les terres du Parapet ceſſoient d’apuyer ſur les contreforts, je <lb/>veux parler des revêtemens qui ſont fort enterrés & </s> <s xml:id="echoid-s1888" xml:space="preserve">dont l’aſſié-<lb/>geant eſt un tems à ne battre que le ſommet des ouvrages, ſans <lb/>pouvoir découvrir le reſte, ainſi on aura toûjours ſujet de rendre <lb/>les revêtemens plus forts que foibles.</s> <s xml:id="echoid-s1889" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1890" xml:space="preserve">Comme on s’eſt toûjours bien trouvé des revêtemens de 30 à <lb/>35 pieds de hauteur, en ne leur donnant que cinq pieds d’épaiſ-<lb/>ſeur au ſommet, il ſemble que ce que l’on peut faire de mieux <lb/>pour ſe ſervir en toute ſûreté du Profil general, ſans être obligé <lb/>de faire tous les calculs que je viens de raporter, c’eſt de donner <lb/>quatre pieds d’épaiſſeur au ſommet du revêtement de dix pieds, <lb/>quatre & </s> <s xml:id="echoid-s1891" xml:space="preserve">demi à celui de vingt, cinq à celui de trente, cinq & </s> <s xml:id="echoid-s1892" xml:space="preserve"><lb/>demi à celui de quarante, & </s> <s xml:id="echoid-s1893" xml:space="preserve">ainſi des autres dont on augmentera <lb/>toûjours l’épaiſſeur de ſix pouces, à meſure que la hauteur aug-<lb/>mentera de dix pieds; </s> <s xml:id="echoid-s1894" xml:space="preserve">& </s> <s xml:id="echoid-s1895" xml:space="preserve">à l’égard des autres dimenſions on les <lb/>déterminera comme elles ſont marquées dans la Table du Profil <lb/>general; </s> <s xml:id="echoid-s1896" xml:space="preserve">pour lors tout ſera bien proportionné, & </s> <s xml:id="echoid-s1897" xml:space="preserve">preſque d’accord <lb/>avec ce que peuvent fournir les régles les plus exactes: </s> <s xml:id="echoid-s1898" xml:space="preserve">il eſt vrai <lb/>que l’épaiſſeur du ſommet du revêtement de dix pieds ſera un peu <lb/>plus grande qu’ellene devroit être; </s> <s xml:id="echoid-s1899" xml:space="preserve">mais ce revêtement en ſoûtien-<lb/>dra plus long-tems l’effet du Canon.</s> <s xml:id="echoid-s1900" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1901" xml:space="preserve">Tout ce que je viens de dire ſert, non-ſeulement à faire voir ce <lb/>que l’on peut penſer pour & </s> <s xml:id="echoid-s1902" xml:space="preserve">contre le Profil general, mais encore <lb/>à mettre les gens du métier en état d’examiner les choſes avec pré-<lb/>ciſion, & </s> <s xml:id="echoid-s1903" xml:space="preserve">par des voyes qui menent à la verité, & </s> <s xml:id="echoid-s1904" xml:space="preserve">dont les prin-<lb/>cipes peuvent ſervir à quantité d’autres ſujets qui auroient raport <lb/>à celui-ci: </s> <s xml:id="echoid-s1905" xml:space="preserve">ainſi quand même on reſteroit dansl’opinion de ſe ſervir <lb/>du Profil general tel qu’il eſt ſans y faire aucun changement, cette <lb/>diſſertation n’en ſeroit pas moins utile; </s> <s xml:id="echoid-s1906" xml:space="preserve">c’eſt pourquoi il n’y a point <lb/>d’aparence qu’on ſoit en droit de me reprocher d’écrire des cho- <pb o="79" file="0107" n="110" rhead="LIVRE I. DE LA THEORIE DE LA MAÇONNERIE."/> ſes ſuperfluës, puiſque les Mathématiques ont toûjours cela d’heu-<lb/>reux, que s’il leur arrive quelquefois d’être apliquées à des ſujets qui <lb/>paroiſſent de petite conſéquence, elles s’y rendent au moins néceſ-<lb/>ſaires par le tour qu’on leur a fait prendre, & </s> <s xml:id="echoid-s1907" xml:space="preserve">c’eſt cette eſpece de <lb/>ſagacité que je cherche ſur toutes choſes à inſinuer à ceux qui veu-<lb/>lent s’inſtruire ſérieuſement, & </s> <s xml:id="echoid-s1908" xml:space="preserve">ſe mettre en état de juger avec <lb/>des vûës claires & </s> <s xml:id="echoid-s1909" xml:space="preserve">diſtinctes de tout ce qui ſe préſente.</s> <s xml:id="echoid-s1910" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1911" xml:space="preserve">J’ay penſé pluſieurs fois en écrivant ce premier Livre, que des <lb/>perſonnes, qui n’ont qu’une médiocre connnoiſſance de l’Algebre, <lb/>ſeroient peut-être embarraſſées de ſçavoir pourquoi après avoir fait <lb/>paſſer tous les termes où ſe trouve l’inconnu, dans le même membre, <lb/>il falloit ajouter de part & </s> <s xml:id="echoid-s1912" xml:space="preserve">d’autre le quarré de la moitié du coëfficient <lb/>du ſecond terme, pour faire de ce membre un quarré parfait; </s> <s xml:id="echoid-s1913" xml:space="preserve">& </s> <s xml:id="echoid-s1914" xml:space="preserve"><lb/>qu’un petit éclairciſſement ſur ce ſujet pouvant leur faire plaiſir, la <lb/>remarque ſuivante ne ſeroit point inutile pour l’Intelligence des <lb/>articles 22, 25, 26, &</s> <s xml:id="echoid-s1915" xml:space="preserve">c.</s> <s xml:id="echoid-s1916" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div135" type="section" level="1" n="83"> <head xml:id="echoid-head102" style="it" xml:space="preserve">52. Remarque ſur la réſolution des Problêmes du <lb/>deuxiéme dégré.</head> <p> <s xml:id="echoid-s1917" xml:space="preserve">Si l’on a deux grandeurs liées enſemble par le ſigne + ou - comme <lb/>y ± a, je dis que le quarré de ces deux grandeurs ſera égal au quarré <lb/>de la premiere, plus au quarré de la ſeconde, plus ou moins le pro-<lb/>duit de la premiere par le double de la ſeconde; </s> <s xml:id="echoid-s1918" xml:space="preserve">ce qui eſt bien <lb/>évident, puiſqu’il vient yy ± 2ay + aa, qui renferme les quarrés de <lb/>y & </s> <s xml:id="echoid-s1919" xml:space="preserve">de a, & </s> <s xml:id="echoid-s1920" xml:space="preserve">le produit de y & </s> <s xml:id="echoid-s1921" xml:space="preserve">de 2a.</s> <s xml:id="echoid-s1922" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1923" xml:space="preserve">De même, ſi la ſeconde des deux grandeurs étoit multipliée ou <lb/>diviſée comme dans cet exemple, y + 2a, y + {3a/2}, y + {5a/2}, y <lb/>- {ab/c}, le quarré donnera toûjours yy + 4ay + 4aa, yy + 3ay <lb/>+ {9aa/4}, yy + 5ay + {25aa/4}, yy - {2aby/c}, + {aabb/cc}, où l’on trouve en-<lb/>core le quarré de la premiere & </s> <s xml:id="echoid-s1924" xml:space="preserve">de la ſeconde grandeur, & </s> <s xml:id="echoid-s1925" xml:space="preserve">le pro-<lb/>duit de la premiere par le double de la ſeconde; </s> <s xml:id="echoid-s1926" xml:space="preserve">car multipliant 2a, <lb/>{3a/2}, {5a/2}, {ab/c}, par deux, il vient 4a, 3a, 5a, {2ab/c}, dont le produit <lb/>par la premiere grandeur y, donne 4ay, 3ay, 5ay, {2ab/c}.</s> <s xml:id="echoid-s1927" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1928" xml:space="preserve">Puiſque les coëfficiens ſont doubles des racines du ſecond quarré, <lb/>on peut conclure que toutes les fois que l’on aura le quarré d’un <lb/>inconnu plus ou moins, cet inconnu multiplié par un coëfficient <pb o="80" file="0108" n="111" rhead="LA SCIENCE DES INGENIEURS."/> quelconque, on pourra regarder ce coëfficient comme le double <lb/>de la racine du quarré, qui manque, pour que l’inconnu ſe trouve <lb/>compris dans un quarré parfait, & </s> <s xml:id="echoid-s1929" xml:space="preserve">qu’ainſi on aur a toûjours la racine <lb/>de ce quarré, en prenant la moitié du coëfficient du ſecond terme.</s> <s xml:id="echoid-s1930" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1931" xml:space="preserve">Quand il arrive que le coëfficient ſe trouve compoſé de pluſieurs <lb/>termes, il faut les ſupoſer n’en valoir tous enſemble qu’un ſeul; <lb/></s> <s xml:id="echoid-s1932" xml:space="preserve">par exemple, ſi l’on avoit yy + {2ay/3} - {3bdy/5c} + 2dy + {bby/d}, on <lb/>ſupoſera {2a/3} - {bd/5c} + 2d + {bb/d} = n; </s> <s xml:id="echoid-s1933" xml:space="preserve">& </s> <s xml:id="echoid-s1934" xml:space="preserve">comme en multipliant <lb/>cette équation par y, l’on a {2ay/3} - {3bdy/5c} + 2dy + {bby/d} = ny, <lb/>on pourra mettre ny, à la place de ſa valeur; </s> <s xml:id="echoid-s1935" xml:space="preserve">& </s> <s xml:id="echoid-s1936" xml:space="preserve">au lieu de ce qui <lb/>précéde on aura yy + ny, qu’on pourra changer en quarré, en y ajoû-<lb/>tantle quarré de la moitié du coëfficient, c’eſt-à-dire le quarré de {n/2}, <lb/>afin d’avoir yy + ny + {nn/4}; </s> <s xml:id="echoid-s1937" xml:space="preserve">& </s> <s xml:id="echoid-s1938" xml:space="preserve">pour éviter les fractions, on peut encore <lb/>ſupoſer le coëfficient complexe égal à 2n, plûtôt qu’à n ſeul, par-<lb/>ce qu’alors ayant 2ny, au lieu de ny, le quarré ſera yy + 2ny + nn.</s> <s xml:id="echoid-s1939" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s1940" xml:space="preserve">Fin du premier Livre.</s> <s xml:id="echoid-s1941" xml:space="preserve"/> </p> <figure> <image file="0108-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0108-01"/> </figure> <pb file="0109" n="112"/> <figure> <image file="0109-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0109-01"/> </figure> </div> <div xml:id="echoid-div136" type="section" level="1" n="84"> <head xml:id="echoid-head103" xml:space="preserve">LA SCIENCE <lb/>DES INGENIEURS <lb/>DANS LA CONDUITE DES TRAVAUX <lb/>DE FORTIFICATION.</head> <head xml:id="echoid-head104" xml:space="preserve">LIVRE SECOND.</head> <head xml:id="echoid-head105" style="it" xml:space="preserve">Qui tr aite de la Mécanique des Voûtes, pour montrer la ma-<lb/>niere de déterminer l’épaiſſeur de leurs Piés-droits.</head> <p> <s xml:id="echoid-s1942" xml:space="preserve">SI l’on a bien conçû ce que je viens d’enſeigner dans <lb/>le Livre précédent, l’on conviendra ſans doute qu’il <lb/>y a une méthode de conſiderer les Sujets qui ſe ra-<lb/>portent à l’Architecture, par laquelle on eſt ſûr de <lb/>ne pas donner dans le faux, dès qu’on ſaura ſe ſer-<lb/>vir heureuſement des connoiſſances acquiſes par l’étude des Ma-<lb/>thématiques; </s> <s xml:id="echoid-s1943" xml:space="preserve">les principes qu’elles nous preſentent ſont d’une <lb/>ſi grande fécondité, qu’il n’y a rien à quoi ils ne ſoient aplicables, <lb/>principalement ceux de la Mécanique. </s> <s xml:id="echoid-s1944" xml:space="preserve">C’eſt vainement qu’on vou-<lb/>dra nous perſuader que la pratique, abandonnée à elle-même, peut <lb/>arriver au point de perfection; </s> <s xml:id="echoid-s1945" xml:space="preserve">l’experience prouve ſouvent <pb o="2" file="0110" n="113" rhead="LA SCIENCE DES INGENIEURS,"/> le contraire, & </s> <s xml:id="echoid-s1946" xml:space="preserve">j’en vais faire voir un exemple au ſujet des Voûtes, <lb/>qui viendra fort à propos, pour faire ſentir combien il eſt de conſe-<lb/>quence de ne pas ſuivre ſans examen les principes qui ne ſont auto-<lb/>riſés que par l’uſage; </s> <s xml:id="echoid-s1947" xml:space="preserve">mais, avant cela, il faut que j’inſinuë de quelle <lb/>maniere ſe fait la pouſſée des Voûtes, afin d’examiner ſile ſentiment <lb/>qu’on en doit avoir peut s’accorder avec les productions de la pra-<lb/>tique.</s> <s xml:id="echoid-s1948" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s1949" xml:space="preserve">Comme je ſerai obligé d’employer encore l’Algebre en parlant <lb/>des Voûtes, bien des gens qui ne l’entendent point ſe mettront <lb/>peut-être de mauvaiſe humeur de ce que, non content d’en avoir <lb/>rempli tout le premier Livre, je m’en ſers encore dans le ſecond; <lb/></s> <s xml:id="echoid-s1950" xml:space="preserve">mais je les prie de m’excuſer & </s> <s xml:id="echoid-s1951" xml:space="preserve">de lire celui-ci tout de ſuite, <lb/>afin de profiter des endroits qui ſont faciles à entendre, tels que les <lb/>Aplications & </s> <s xml:id="echoid-s1952" xml:space="preserve">la plus grande partie des Remarques: </s> <s xml:id="echoid-s1953" xml:space="preserve">en recompenſe, <lb/>dans le deſſein de leur faire ma cour, ils trouveront dans le quatrié-<lb/>me Chapitre des Méthodes générales pour avoir l’épaiſſeur des Piés-<lb/>droits de toute ſorte de Voûtes par le ſeul calcul des nombres, ſans <lb/>le melange d’aucun Caractere Algebrique; </s> <s xml:id="echoid-s1954" xml:space="preserve">moyennant cette con-<lb/>dition, j’eſpere que nous vivrons bien enſemble.</s> <s xml:id="echoid-s1955" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div137" type="section" level="1" n="85"> <head xml:id="echoid-head106" xml:space="preserve">CHAPITRE PREMIER.</head> <head xml:id="echoid-head107" style="it" xml:space="preserve">Où l’on enſeigne comme ſe fait la pouſſée des Voûtes.</head> <p> <s xml:id="echoid-s1956" xml:space="preserve">SI l’on conſidere la Voûte rAZ, formée par une quantité de <lb/> <anchor type="note" xlink:label="note-0110-01a" xlink:href="note-0110-01"/> Vouſſoirs égaux, l’on ſait que ces Vouſſoirs, quand il s’agit d’une <lb/>Voûte en plain-ceintre, ont été taillés de maniere que leurs joints <lb/>prolongés viennent ſe rencontrer au centre du demi cercle; </s> <s xml:id="echoid-s1957" xml:space="preserve">ainſi <lb/>ces Vouſſoirs étant plus larges à la tête qu’en bas, doivent être re-<lb/>gardés comme des coins qui s’apuyent & </s> <s xml:id="echoid-s1958" xml:space="preserve">ſe ſoutiennent les uns les <lb/>autres, & </s> <s xml:id="echoid-s1959" xml:space="preserve">réſiſtent mutuellement à l’effort de leur péſanteur qui <lb/>les porte à tomber: </s> <s xml:id="echoid-s1960" xml:space="preserve">car nous ſupoſons ici (pour mieux apercevoir <lb/>l’effet des Vouſſoirs) qu’ils ne ſont entretenus par aucun ciment, <lb/>& </s> <s xml:id="echoid-s1961" xml:space="preserve">ont la liberté de gliſſer comme ſi leurs faces étoient polies, nous <lb/>ſupoſerons encore que les points O, A, D, F, &</s> <s xml:id="echoid-s1962" xml:space="preserve">c. </s> <s xml:id="echoid-s1963" xml:space="preserve">marquent les <lb/>centres de gravité des Vouſſoirs, & </s> <s xml:id="echoid-s1964" xml:space="preserve">qu’en commençant par la <lb/>clef, on a tiré par les points A, & </s> <s xml:id="echoid-s1965" xml:space="preserve">O, une ligne AV perpendicu-<lb/>laire ſur la face C; </s> <s xml:id="echoid-s1966" xml:space="preserve">que par les points A & </s> <s xml:id="echoid-s1967" xml:space="preserve">D, on en a tiré une <lb/>autre AP, ſur la face B; </s> <s xml:id="echoid-s1968" xml:space="preserve">par les points D & </s> <s xml:id="echoid-s1969" xml:space="preserve">F, on en a tiré une <lb/>autre DQ, ſur la face E; </s> <s xml:id="echoid-s1970" xml:space="preserve">& </s> <s xml:id="echoid-s1971" xml:space="preserve">qu’on a continué de même, afin d’en <pb o="3" file="0111" n="114" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> avoir autant que de Vouſſoirs: </s> <s xml:id="echoid-s1972" xml:space="preserve">cela poſé, conſiderez que la clefétant <lb/>ſoutenuë par les deux Vouſſoirs voiſins, comme par des plans in-<lb/>clinés, elle fait le même effet qu’un coin, qui, étant chaſſé dans un <lb/>corps, tend à le partager en deux par un effort qui ſe fait ſelon <lb/>des directions AB, & </s> <s xml:id="echoid-s1973" xml:space="preserve">AC, perpendiculaires aux deux plans in-<lb/>clinés BI, & </s> <s xml:id="echoid-s1974" xml:space="preserve">CI; </s> <s xml:id="echoid-s1975" xml:space="preserve">car l’on peut prendre ici la péſanteur du coin pour <lb/>la puiſſance qui le chaſſe <anchor type="note" xlink:href="" symbol="*"/>; </s> <s xml:id="echoid-s1976" xml:space="preserve">ainſi les deux puiſſances qui ſoûtien- <anchor type="note" xlink:label="note-0111-01a" xlink:href="note-0111-01"/> dront les faces BI & </s> <s xml:id="echoid-s1977" xml:space="preserve">CI, en équilibre contre la force du coin, agi-<lb/>ront ſuivant des lignes de direction AP, & </s> <s xml:id="echoid-s1978" xml:space="preserve">AV, perpendiculaires <lb/>aux mêmes faces, & </s> <s xml:id="echoid-s1979" xml:space="preserve">comme ces directions viennent ſe rencontrer <lb/>au centre de gravité A, où l’on peut ſupoſer que la péſanteur du <lb/>coin eſt réünie, on peut donc dire que ces puiſſances auront beſoin <lb/>d’autant plus de force que les angles P AI, & </s> <s xml:id="echoid-s1980" xml:space="preserve">V AI, ſeront plus ou-<lb/>verts, ou ce qui revient au même, que les faces BI, & </s> <s xml:id="echoid-s1981" xml:space="preserve">CI, ſeront <lb/>moins inclinées par raport à la verticale AI; </s> <s xml:id="echoid-s1982" xml:space="preserve">car ſi elle l’étoit infi-<lb/>niment peu, c’eſt-à-dire, preſque perpendiculaire à l’horiſon, les <lb/>directions des puiſſances P & </s> <s xml:id="echoid-s1983" xml:space="preserve">V, ſe trouvant directement opoſées, <lb/>il leur faudroit une force extrême pour pouvoir ſoûtenir le point <lb/>péſant A, équivalent au Vouſſoir, au lieu que plus les angles qu’elles <lb/>formeront avec la verticale AI, ſeront aigus, & </s> <s xml:id="echoid-s1984" xml:space="preserve">moins elles au-<lb/>ront beſoin de force; </s> <s xml:id="echoid-s1985" xml:space="preserve">puiſqu’alors leurs directions n’étant plus ſi <lb/>opoſées entr’elles, elles le ſeront davantage à la péſanteur du poids.</s> <s xml:id="echoid-s1986" xml:space="preserve"/> </p> <div xml:id="echoid-div137" type="float" level="2" n="1"> <note position="left" xlink:label="note-0110-01" xlink:href="note-0110-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>4. <lb/><emph style="sc">Fig</emph>. 1.</note> <note symbol="*" position="right" xlink:label="note-0111-01" xlink:href="note-0111-01a" xml:space="preserve">V. le C. <lb/>Art. 810.</note> </div> <p> <s xml:id="echoid-s1987" xml:space="preserve">Ce que nous venons de voir au ſujet de la clef, pourra auſſi ſe <lb/>dire des Vouſſoirs D & </s> <s xml:id="echoid-s1988" xml:space="preserve">O; </s> <s xml:id="echoid-s1989" xml:space="preserve">car le Vouſſoir D, par exemple, ayant <lb/>auſſi la figure d’un coin, il agira pour écarter les deux faces voiſi-<lb/>nes; </s> <s xml:id="echoid-s1990" xml:space="preserve">mais non pas ſi puiſſamment ſur la face E, que la clef A, fait ſur <lb/>la face B, à cauſe que le plan EI, étant plus incliné que le Plan <lb/>BI, par raport à la verticale AI, l’angle QDK, formé par la ligne <lb/>de direction DK, & </s> <s xml:id="echoid-s1991" xml:space="preserve">la ligne de direction DQ, de la puiſſance qui <lb/>ſeroit en équilibre avec l’effort que fait le Vouſſoir D, ſur la face <lb/>E, eſt plus aigu que l’angle P AI; </s> <s xml:id="echoid-s1992" xml:space="preserve">de même le Vouſſoir F, fera <lb/>encore moins d’effort contre la face G, que le précédent n’en fait <lb/>contre la face E, parce que l’angle RFL, eſt encore plus aigu que <lb/>l’angle QDK. </s> <s xml:id="echoid-s1993" xml:space="preserve">Or comme toutes les puiſſances qui ſoûtiendroient <lb/>les Vouſſoirs depuis la clef juſqu’aux piés-droits agiront toûjours <lb/>ſelon des directions qui feront des angles plus aigus avec les <lb/>lignes tirées du centre de gravité des Vouſſoirs, leur force ira donc <lb/>toûjours en diminuant; </s> <s xml:id="echoid-s1994" xml:space="preserve">& </s> <s xml:id="echoid-s1995" xml:space="preserve">comme ces puiſſances ont été ſupoſées <lb/>équivalentes aux efforts que font les Vouſſoirs, il s’enſuit que ceux-<lb/>ci pouſſent avec une force qui va toûjours en diminuant depuis la <lb/>clef juſqu’aux piés-droits.</s> <s xml:id="echoid-s1996" xml:space="preserve"/> </p> <pb o="4" file="0112" n="115" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s1997" xml:space="preserve">Cependant, comme le Vouſſoir D, agit en même tems ſur les <lb/>deux faces E, & </s> <s xml:id="echoid-s1998" xml:space="preserve">B, on voit qu’il ne peut s’apuyer contre la face <lb/>B, ſans s’opoſer en partie à l’effort que fait la clef contre cette <lb/>même face, & </s> <s xml:id="echoid-s1999" xml:space="preserve">que par conſéquent il doit arriver une deſtruction <lb/>de forces entre la clef & </s> <s xml:id="echoid-s2000" xml:space="preserve">le vouſſoir D: </s> <s xml:id="echoid-s2001" xml:space="preserve">de même les deux vouſ-<lb/>ſoirs F & </s> <s xml:id="echoid-s2002" xml:space="preserve">D, agiſſants auſſi dans un ſens opoſé eu égard à la face <lb/>E, il y aura encore une deſtruction de forces entre ces deux vouſ-<lb/>foirs, ainſi des autres ſuivans pris d’eux deux. </s> <s xml:id="echoid-s2003" xml:space="preserve">Il eſt bien vrai que <lb/>comme la clef pouſſe avec plus de force contre la face B, que le <lb/>vouſſoir D, n’en a pour la repouſſer, la deſtruction de forces ne <lb/>ſera point entiere, il en reſtera toûjours à la clef une certaine quan-<lb/>tité, mais qui ne ſera pas ſi grande qu’elle eût été ſi le vouſſoir D, <lb/>ne faiſoit aucun effet ſur la face B: </s> <s xml:id="echoid-s2004" xml:space="preserve">de même quoique le vouſſoir <lb/>D, ſoit repouſſé par l’autre F, il reſtera encore à ce premier une <lb/>certaine quantité de force; </s> <s xml:id="echoid-s2005" xml:space="preserve">ainſi en général on peut dire qu’un vouſ-<lb/>ſoir qui eſt au-deſſus d’un autre, a plus de force pour pouſſer l’in-<lb/>ferieur, que celui-ci n’en a pour le repouſſer, & </s> <s xml:id="echoid-s2006" xml:space="preserve">comme les vouſ-<lb/>ſoirs depuis la clef ju’qu’à la naiſſance de la voûte, vont toûjours <lb/>en exerceant une moindre partie de leur péſanteur, ſur ceux qui <lb/>ſont immediatement deſſous l’effort que chaque vouſſoir fait pour <lb/>repouſſer; </s> <s xml:id="echoid-s2007" xml:space="preserve">celui qui eſt ſuperieur va toûjours en diminuant à me-<lb/>ſure que les plans EI, & </s> <s xml:id="echoid-s2008" xml:space="preserve">GI, ſont moins inclinés à l’horiſon, par-<lb/>ce qu’alors ces Plans portent une plus grande partie du poids, par <lb/>conſequent celle qui tend à gliſſer fait moins d’effet contre la puiſ-<lb/>ſance qui voudroit lui réſiſter, tellement qu’on peut dire que l’ef-<lb/>fort que tous les vouſſoirs font de bas en haut, va toûjours en di-<lb/>minuant en venant de la clef vers les piés-droits dans la même rai-<lb/>ſon que l’effort qui ſe fait du haut en bas.</s> <s xml:id="echoid-s2009" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2010" xml:space="preserve">Comme le réſultat de l’effort que les vouſſoirs font à droit & </s> <s xml:id="echoid-s2011" xml:space="preserve">à <lb/>gauche de la clef tendra à écarter ce qui leur peut réſiſter, c’eſt-à-<lb/>dire les piés-droits, c’eſt l’effort total de tous ces vouſſoirs qu’on <lb/>apelle pouſſée, qui n’agit pourtant pas tout-à-fait comme je viens de <lb/>l’inſinuer, puiſqu’il ne paroit pas poſſible que tous les vouſſoirs qui <lb/>compoſent une V oûte puiſſent ſe ſoûtenir d’eux-mêmes ſans être en-<lb/>tretenus par du Ciment ou Mortier; </s> <s xml:id="echoid-s2012" xml:space="preserve">carles vouſſoirs ſuperieurs ayant <lb/>plus de force pour pouſſer les inferieurs, que ceux-ci n’en ont pour <lb/>les repouſſer, il eſt conſtant que ceux qui auront moins de force <lb/>ſeront contrains de s’élever: </s> <s xml:id="echoid-s2013" xml:space="preserve">ce qui laiſſant la liberté de tomber à <lb/>ceux qui ſont au-deſſus, tout l’arrangement des vouſſoirs ſe dé-<lb/>truiroit, & </s> <s xml:id="echoid-s2014" xml:space="preserve">par conſéquent la Voûte même; </s> <s xml:id="echoid-s2015" xml:space="preserve">& </s> <s xml:id="echoid-s2016" xml:space="preserve">ce n’eſt que dans le <lb/>cas où tous les vouſſoirs auroient une pouſſée égale qu’ils ſe main- <pb o="5" file="0113" n="116" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> tiendroient en équilibre ſans le ſecours d’aucune matiere qui les <lb/>entretiennent; </s> <s xml:id="echoid-s2017" xml:space="preserve">mais pour cela il faudroit augmenter leur péſanteur, <lb/>en venant de la clef vers les piés-droits, afin que chacun puiſſe par <lb/>ſon poids réſiſter d’autant plus, que le Plan, ſur lequel il eſt apuyé, <lb/>eſt moins incliné par raport à celui qui eſt au-deſſus: </s> <s xml:id="echoid-s2018" xml:space="preserve">or puiſqu’une <lb/>Voûte telle que celle qui eſt repreſentée dans la figure ne pourroit <lb/>ſe ſoutenir ſans ciment, ce n’eſt donc pas les efforts effectifs des <lb/>vouſſoirs qu’il faut conſidérer, mais ſeulement la tendance qu’ils <lb/>ont à agir.</s> <s xml:id="echoid-s2019" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2020" xml:space="preserve">Comme il doit y avoir ſur la baſe de chaque pié-droit un point <lb/>où vient aboutir l’effort qui ſe fait à droit & </s> <s xml:id="echoid-s2021" xml:space="preserve">à gauche, on remar-<lb/>quera que ces points répondent neceſſairement aux angles S & </s> <s xml:id="echoid-s2022" xml:space="preserve">X, <lb/>qu’on doit regarder comme des points d’apuy qui apartiennent à des <lb/>léviers, qui à la vérité ne ſont point ſenſibles aux yeux, mais qui <lb/>pour cela n’en ont pas moins de réalité, comme on en va juger.</s> <s xml:id="echoid-s2023" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2024" xml:space="preserve">Si la pouſſée d’une Voûte n’étoit point partagée le long de cha-<lb/>que quart de cercle AR & </s> <s xml:id="echoid-s2025" xml:space="preserve">AZ, mais qu’elle fut toute réünie à deux <lb/>points, comme R & </s> <s xml:id="echoid-s2026" xml:space="preserve">Z; </s> <s xml:id="echoid-s2027" xml:space="preserve">il eſt conſtant qu’on auroit de chaque côté <lb/>un lévier recourbé RSH, & </s> <s xml:id="echoid-s2028" xml:space="preserve">ZXM, dont les puiſſances ſeroient apliquées <lb/>aux extrêmités R & </s> <s xml:id="echoid-s2029" xml:space="preserve">Z, des bras SR & </s> <s xml:id="echoid-s2030" xml:space="preserve">ZX, & </s> <s xml:id="echoid-s2031" xml:space="preserve">les poids qui ſont <lb/>équivalens à la réſiſtance des piés-droits aux extrêmités H & </s> <s xml:id="echoid-s2032" xml:space="preserve">M, <lb/>des bras SH & </s> <s xml:id="echoid-s2033" xml:space="preserve">XM; </s> <s xml:id="echoid-s2034" xml:space="preserve">mais comme il y a autant de puiſſances que <lb/>de vouſſoirs, ſi l’on en excepte les deux R & </s> <s xml:id="echoid-s2035" xml:space="preserve">Z, qui n’ont point de <lb/>pouſſée, il faut donc que chaque puiſſance ait ſon lévier particulier, <lb/>ou que ce lévier ſoit exprimé par une ligne qui puiſſe être admiſe <lb/>en ſa place. </s> <s xml:id="echoid-s2036" xml:space="preserve">Or comme ces lignes ne peuvent être que les perpen-<lb/>diculaires SP, SQ, SR &</s> <s xml:id="echoid-s2037" xml:space="preserve">c. </s> <s xml:id="echoid-s2038" xml:space="preserve">tirées du point d’apui S, ſur les directions <lb/>des puiſſances qui ſoutiendroient les vouſſoirs, l’on voit clairement <lb/>à quoi doit ſe réduire tout le mécaniſme qui régne ici; </s> <s xml:id="echoid-s2039" xml:space="preserve">deſorte que <lb/>pour proportionner l’épaiſſeur des piés-droits, à la pouſſée d’une <lb/>Voûte, il faut ſavoir trouver l’effort que fait chaque vouſſoir par <lb/>raport à ſa péſanteur abſoluë & </s> <s xml:id="echoid-s2040" xml:space="preserve">les perpendiculaires SP, SQ, SR &</s> <s xml:id="echoid-s2041" xml:space="preserve">c.</s> <s xml:id="echoid-s2042" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2043" xml:space="preserve">On peut tirer pluſieurs conſéquences de ce que nous venons de <lb/>dire: </s> <s xml:id="echoid-s2044" xml:space="preserve">la premiere, que dans une Voûte où l’on ſupoſeroit (comme <lb/>on l’a fait ici,) que les vouſſoirs ne ſont entretenus par aucun ci-<lb/>ment, plus leur tête ſera petite, & </s> <s xml:id="echoid-s2045" xml:space="preserve">plus la Voûte aura de pouſſée; <lb/></s> <s xml:id="echoid-s2046" xml:space="preserve">car ces vouſſoirs étant régardés comme des coins, ils auront d’au-<lb/>tant plus de force, que leur face prolongée feront un angle plus <lb/>aigu: </s> <s xml:id="echoid-s2047" xml:space="preserve">d’ailleurs les perpendiculaires SP, SQ, SR &</s> <s xml:id="echoid-s2048" xml:space="preserve">c. </s> <s xml:id="echoid-s2049" xml:space="preserve">qui répondent <lb/>aux puiſſances qui ſoutiennent les premiers vouſſoirs, devenant plus <lb/>grandes à meſure que les faces de ces vouſſoirs ſeront moins incli- <pb o="6" file="0114" n="117" rhead="LA SCIENCE DES INGENIEURS,"/> nées à la verticale AI, la longueur des bras des léviers ſe trouvera <lb/>augmentée: </s> <s xml:id="echoid-s2050" xml:space="preserve">ce qui donnera plus d’avantage à la pouſſée des vouſ-<lb/>ſoirs.</s> <s xml:id="echoid-s2051" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2052" xml:space="preserve">La ſeconde, c’eſt que plus la Voûte aura d’épaiſſeur, & </s> <s xml:id="echoid-s2053" xml:space="preserve">plus la <lb/>pouſſée ſera grande, puiſque les vouſſoirs devenant plus longs & </s> <s xml:id="echoid-s2054" xml:space="preserve"><lb/>par conſéquent plus péſans, ils agiront plus puiſſamment.</s> <s xml:id="echoid-s2055" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2056" xml:space="preserve">La troiſiéme, que plus les piés-droits qui ſoutiennent une Voû-<lb/>te ſeront élevés, & </s> <s xml:id="echoid-s2057" xml:space="preserve">plus il leur faudra d’épaiſſeur pour ſoutenir la <lb/>pouſſée; </s> <s xml:id="echoid-s2058" xml:space="preserve">car comme on ne peut augmenter la hauteur des piés-droits <lb/>ſans que les perpendiculaires SP, SQ &</s> <s xml:id="echoid-s2059" xml:space="preserve">c. </s> <s xml:id="echoid-s2060" xml:space="preserve">ne deviennent auſſi plus <lb/>grandes, il s’enſuit que les bras des léviers qui répondent aux puiſ-<lb/>ſances, ou ſi l’on veut à l’effort de chaque vouſſoir, ſe trouvant <lb/>augmentés, ils auront tous enſemble plus de force pour renverſer <lb/>les piés-droits.</s> <s xml:id="echoid-s2061" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2062" xml:space="preserve">Quoique ce que je viens de dire ſoit bien naturel, c’eſt pourtant <lb/>à quoi les Architectes qui ont parlé des Voûtes n’ont fait aucune at-<lb/>tention; </s> <s xml:id="echoid-s2063" xml:space="preserve">&</s> <s xml:id="echoid-s2064" xml:space="preserve">, afin qu’on puiſſe en juger, voici comme parle Mr. <lb/></s> <s xml:id="echoid-s2065" xml:space="preserve">Blondel dans ſon Cours d’Architecture, qui eſt le premier qui m’eſt <lb/>tombé ſous la main. </s> <s xml:id="echoid-s2066" xml:space="preserve">Il faut (dit-il) „donner des épaiſſeurs aux pies-<lb/>„droits qui ſoutiennent des Voûtes ſelon la difference des pouſſées, <lb/>„& </s> <s xml:id="echoid-s2067" xml:space="preserve">c’eſt ce qui ſe fait par une régle de pratique en cette maniere.</s> <s xml:id="echoid-s2068" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2069" xml:space="preserve">Partagez l’arc en trois parties égales, & </s> <s xml:id="echoid-s2070" xml:space="preserve">menant une des cor-<lb/> <anchor type="note" xlink:label="note-0114-01a" xlink:href="note-0114-01"/> des par le point de l’impoſte, prenez en dehors ſur la même, <lb/>continuez une ligne qui lui ſoit égale, la droite, menée à plomb <lb/>par l’extrêmité de cette ligne, déterminera l’épaiſſeur du pié-<lb/>droit; </s> <s xml:id="echoid-s2071" xml:space="preserve">comme ſi diviſant l’arc ACBD, en trois parties égales aux <lb/>points CD, je mene la corde DB, paſſant par le point de l’im-<lb/>poſte en B, je n’ai qu’à prendre en dehors ſur la même droite <lb/>continuée, la partie BE, égale à BD, & </s> <s xml:id="echoid-s2072" xml:space="preserve">menant les deux perpen-<lb/>diculaires EG & </s> <s xml:id="echoid-s2073" xml:space="preserve">BF, elles détermineront l’épaiſſeur du pié-droit <lb/>BGEF, qui ſera proportionnée à la pouſſée de l’arc ACDB.</s> </p> <p> <s xml:id="echoid-s2074" xml:space="preserve">L’on voit que dans cette régle il n’eſt fait aucune mention de <lb/>l’épaiſſeur de la Voûte, ni de la hauteur des piés-droits, qui ſont <lb/>pourtant deux circonſtances auſquelles il faut avoir égard abſolu-<lb/>ment pour les raiſons que j’en ai données plus haut.</s> </p> <div xml:id="echoid-div138" type="float" level="2" n="2"> <note position="left" xlink:label="note-0114-01" xlink:href="note-0114-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 5. <lb/>6. & 9.</note> </div> <div xml:id="echoid-div139" type="section" level="2" n="1"> <head xml:id="echoid-head108" xml:space="preserve">PRINCIPE TIRE’ DE LA MECANIQUE.</head> <p> <s xml:id="echoid-s2075" xml:space="preserve">2. </s> <s xml:id="echoid-s2076" xml:space="preserve">Il eſt démontré dans la Mécanique que trois puiſſances P, Q, R, <lb/> <anchor type="note" xlink:label="note-0114-02a" xlink:href="note-0114-02"/> qui tirent ou pouſſent au tour d’un point A, ſelon des directions <lb/>AP, AQ, AR, ſeront en équilibres entr’elles, ſi après avoir fait <pb o="7" file="0115" n="118" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> le paralellograme ABCD, la puiſſance P, eſt exprimée par le côté <lb/>AB, la puiſſance Q, par le côté AD, & </s> <s xml:id="echoid-s2077" xml:space="preserve">la puiſſance R, par la <lb/>diagonale CA: </s> <s xml:id="echoid-s2078" xml:space="preserve">ou, ce qui revient au même, ſi chaque puiſſance eſt <lb/>exprimée par un des côtés du triangle ABC, parce qu’à la place de <lb/>AD, l’on pourra prendre BC, qui lui eſt égal <anchor type="note" xlink:href="" symbol="*"/>; </s> <s xml:id="echoid-s2079" xml:space="preserve">ſupoſant donc <anchor type="note" xlink:label="note-0115-01a" xlink:href="note-0115-01"/> qu’on ſoit bien prevenu de cette verité, voici une propoſition <lb/>fondamentale qu’on en peut tirer.</s> <s xml:id="echoid-s2080" xml:space="preserve"/> </p> <div xml:id="echoid-div139" type="float" level="3" n="1"> <note position="left" xlink:label="note-0114-02" xlink:href="note-0114-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 2.</note> <note symbol="*" position="right" xlink:label="note-0115-01" xlink:href="note-0115-01a" xml:space="preserve">V. le C. <lb/>Art. 767.</note> </div> <p> <s xml:id="echoid-s2081" xml:space="preserve">Ayant trois puiſſances P, Q, R, qui tirent ou pouſſent toutes <lb/>trois enſemble au tour du point A, je dis qu’elles ſeront en équi-<lb/>libres, ſi la force avec laquelle chacune agit eſt exprimée par un <lb/>des côtés du triangle EFG, qui couperoit en angles droits la ligne <lb/>de direction de chaque puiſſance.</s> <s xml:id="echoid-s2082" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2083" xml:space="preserve">Pour le prouver, remarquez que ſi la ligne AO, eſt perpendicu-<lb/>laire ſur le côté EF; </s> <s xml:id="echoid-s2084" xml:space="preserve">& </s> <s xml:id="echoid-s2085" xml:space="preserve">la ligne CT, ſur le côté EG (comme nous <lb/>le ſupoſons) l’on aura les deux triangles AOF & </s> <s xml:id="echoid-s2086" xml:space="preserve">FTE, ſemblables, <lb/>puiſqu’ils ont chacun un angle droit, & </s> <s xml:id="echoid-s2087" xml:space="preserve">l’angle OFT, qui leur eſt <lb/>commun; </s> <s xml:id="echoid-s2088" xml:space="preserve">ainſi l’angle E, ſera égal à l’angle O A E. </s> <s xml:id="echoid-s2089" xml:space="preserve">Par un ſembla-<lb/>ble raiſonnement on verra auſſi que le triangle FAS eſt ſemblable <lb/>au triangle FTG, & </s> <s xml:id="echoid-s2090" xml:space="preserve">que de même l’angle G, ſera égal à l’angle <lb/>FAS; </s> <s xml:id="echoid-s2091" xml:space="preserve">mais comme ce dernier l’eſt encore à l’angle alterne BCA, il <lb/>s’enſuit donc que le triangle ABC eſt ſemblable au triangle EFG: <lb/></s> <s xml:id="echoid-s2092" xml:space="preserve">ainſi les trois côtés du grand triangle pourront donc être pris à la <lb/>place de ceux du petit, & </s> <s xml:id="echoid-s2093" xml:space="preserve">par conſequent exprimer le raport de <lb/>chaque puiſſance dont ils coupent la ligne de direction en angles <lb/>droits; </s> <s xml:id="echoid-s2094" xml:space="preserve">mais comme nous avons vû que ces trois puiſſances étoient <lb/>en équilibre, lorſque leur raport étoit exprimé par les côtés du petit <lb/>triangle ABC, l’on peut donc dire qu’elles ſeront encore en équilibre <lb/>quand leur raport ſera exprimé par les côtés du triangle EFG. </s> <s xml:id="echoid-s2095" xml:space="preserve">C. </s> <s xml:id="echoid-s2096" xml:space="preserve"><lb/>Q. </s> <s xml:id="echoid-s2097" xml:space="preserve">F. </s> <s xml:id="echoid-s2098" xml:space="preserve">D.</s> <s xml:id="echoid-s2099" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div141" type="section" level="2" n="2"> <head xml:id="echoid-head109" xml:space="preserve"><emph style="sc">Corollaire</emph> <emph style="sc">Premier</emph>.</head> <p> <s xml:id="echoid-s2100" xml:space="preserve">3. </s> <s xml:id="echoid-s2101" xml:space="preserve">Il ſuit que quand on aura trois puiſſances P, Q, R, qui tirent <lb/> <anchor type="note" xlink:label="note-0115-02a" xlink:href="note-0115-02"/> ou pouſſent au tour du point H, ſi elles ſont en équilibre, on con-<lb/>noîtra toûjours le raport que ces puiſſances ont entr’elles, puiſqu’on <lb/>n’aura qu’à couper chaque ligne de direction en angles droits par <lb/>une ligne tirée à telle diſtance que l’on voudra du point H; </s> <s xml:id="echoid-s2102" xml:space="preserve">car ces <lb/>trois lignes venant à ſe rencontrer, donneront les côtés du trian-<lb/>gle IKL, qui exprimeront le raport des puiſſances; </s> <s xml:id="echoid-s2103" xml:space="preserve">c’eſt-à-dire, <lb/>que ſil’on ſupoſe que la puiſſance P, ſoit exprimée par IK, la puiſ-<lb/>ſance Q, le ſera par KL, & </s> <s xml:id="echoid-s2104" xml:space="preserve">la puiſſance R, par IL.</s> <s xml:id="echoid-s2105" xml:space="preserve"/> </p> <div xml:id="echoid-div141" type="float" level="3" n="1"> <note position="right" xlink:label="note-0115-02" xlink:href="note-0115-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <pb o="8" file="0116" n="119" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div143" type="section" level="2" n="3"> <head xml:id="echoid-head110" xml:space="preserve"><emph style="sc">Corollaire</emph> <emph style="sc">Second</emph>.</head> <p> <s xml:id="echoid-s2106" xml:space="preserve">4. </s> <s xml:id="echoid-s2107" xml:space="preserve">Il ſuit encore que connoiſſant les trois côtés du triangle IKL, <lb/> <anchor type="note" xlink:label="note-0116-01a" xlink:href="note-0116-01"/> avec une des trois puiſſances, on pourra connoître les deux autres <lb/>puiſſances; </s> <s xml:id="echoid-s2108" xml:space="preserve">car ſi (par exemple) l’on a la puiſſance P, & </s> <s xml:id="echoid-s2109" xml:space="preserve">qu’on <lb/>veüille connoître la ſeconde Q, on n’aura qu’à dire comme le côté <lb/>KI, eſt au côté KL, ainſi la puiſſance P, eſt à la puiſſance Q, que <lb/>l’on trouvera par la régle de proportion auſſi-bien que la troiſiéme <lb/>puiſſance R.</s> <s xml:id="echoid-s2110" xml:space="preserve"/> </p> <div xml:id="echoid-div143" type="float" level="3" n="1"> <note position="left" xlink:label="note-0116-01" xlink:href="note-0116-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> </div> <div xml:id="echoid-div145" type="section" level="2" n="4"> <head xml:id="echoid-head111" xml:space="preserve"><emph style="sc">Corollaire</emph> <emph style="sc">Troisie’me</emph>.</head> <p> <s xml:id="echoid-s2111" xml:space="preserve">5. </s> <s xml:id="echoid-s2112" xml:space="preserve">Dans les triangles les ſinus des angles étant dans la même rai-<lb/>ſon que leurs côtés opoſés, on peut ajoûter encore que ſi l’on avoit <lb/>un triangle IKL, dont les trois côtés fuſſent en mêmé raiſon que <lb/>les puiſſances PQR, ſi on ne connoiſſoit pas ces côtés, il ſuffiroit <lb/>de connoître la valeur des angles qui leur ſont opoſés, parce que <lb/>les ſinus de ces angles pouvant être pris pour les côtés mêmes, ils <lb/>exprimeront plus exactement le raport en nombre, & </s> <s xml:id="echoid-s2113" xml:space="preserve">par conſé-<lb/>quent les puiſſances, deſorte que ſi on connoiſſoit la valeur de la <lb/>puiſſance Q, & </s> <s xml:id="echoid-s2114" xml:space="preserve">les trois angles I, K, L, on trouvera les deux au-<lb/>tres puiſſances P & </s> <s xml:id="echoid-s2115" xml:space="preserve">R, en ſe ſervant des Tables de Sinus.</s> <s xml:id="echoid-s2116" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div146" type="section" level="2" n="5"> <head xml:id="echoid-head112" xml:space="preserve"><emph style="sc">Corollaire</emph> <emph style="sc">Quatrie’me</emph>.</head> <p> <s xml:id="echoid-s2117" xml:space="preserve">6. </s> <s xml:id="echoid-s2118" xml:space="preserve">Il ſuit enfin que ſi on a trois puiſſances, dont deux priſes <lb/>enſemble ſoient plus grandes que la troiſiéme, connoiſſant le <lb/>raport de ces trois puiſſances, on pourra déterminer ſelon quelle <lb/>direction chaque puiſſance doit tirer ou pouſſer, pour qu’agiſſant <lb/>toutes enſemble autour d’un point, elles ſoient en équilibre, puiſ-<lb/>que pour cela il ne faut que ſe donner trois lignes qui ayent entre <lb/>elles le même raport que les trois puiſſances en queſtion, enſuite <lb/>faire un triangle de ces trois lignes; </s> <s xml:id="echoid-s2119" xml:space="preserve">après quoi ſi d’un point quel-<lb/>conque pris dans la ſuperficie du triangle, l’on abbaiſſe des perpen-<lb/>diculaires ſur les côtés, elles détermineront les directions, ou, ce qui <lb/>eſt la même choſe, les angles que les puiſſances doivent former <lb/>entr’elles.</s> <s xml:id="echoid-s2120" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div147" type="section" level="2" n="6"> <head xml:id="echoid-head113" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s2121" xml:space="preserve">7. </s> <s xml:id="echoid-s2122" xml:space="preserve">Il n’eſt pas neceſſaire que les trois puiſſances P, Q, R, ti-<lb/>rent ou pouſſent toutes trois enſemble le point H, pour être en <pb o="9" file="0117" n="120" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> équilibre, il peut y en avoir deux qui tirent, & </s> <s xml:id="echoid-s2123" xml:space="preserve">une autre qui le <lb/>pouſſe en ſens contraire.</s> <s xml:id="echoid-s2124" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div148" type="section" level="2" n="7"> <head xml:id="echoid-head114" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s2125" xml:space="preserve">8. </s> <s xml:id="echoid-s2126" xml:space="preserve">On prendra garde auſſi que ce n’eſt pas une neceſſité que les <lb/>trois côtés du triangle, qui déterminent le raport des puiſſances, <lb/>ſoient coupés par les lignes de directions de ces puiſſances, ni que le <lb/>point où ces puiſſances concourent ſoit renfermé dans ce triangle, <lb/>puiſqu’il ſuffit que les côtés prolongés du triangle ſoient coupés en <lb/>angles droits; </s> <s xml:id="echoid-s2127" xml:space="preserve">par exemple, ſi les côtés du triangle MKN, ſont diſ-<lb/>poſés de façon que quelqu’un d’eux, comme KM & </s> <s xml:id="echoid-s2128" xml:space="preserve">KN, étant pro-<lb/>longés vers I & </s> <s xml:id="echoid-s2129" xml:space="preserve">vers L, coupent les directions HP & </s> <s xml:id="echoid-s2130" xml:space="preserve">HQ, a an-<lb/>gles droits & </s> <s xml:id="echoid-s2131" xml:space="preserve">que la direction HR, prolongée vers O, aille couperle <lb/>côté MN, auſſi à angles droits, je dis que les côtés du triangle MKN, <lb/>détermineront encore le rapport des puiſſances, quoique le point <lb/>H ne ſoit point dans ce triangle; </s> <s xml:id="echoid-s2132" xml:space="preserve">car les choſes étant telles que nous <lb/>le ſupoſons, les lignes MN & </s> <s xml:id="echoid-s2133" xml:space="preserve">IL ſeront paralelles, puiſqu’elles ſont <lb/>toutes deux coupées à angles droits par la ligne OR: </s> <s xml:id="echoid-s2134" xml:space="preserve">par conſe-<lb/>quent le triangle MKN ſera ſemblable à IKL; </s> <s xml:id="echoid-s2135" xml:space="preserve">or ſi les côtés de ce <lb/>dernier expriment le raport des trois puiſſances PQR, comme nous <lb/>l’avons fait voir ci-devant, ceux de l’autre MKN, exprimeront <lb/>auſſi le même raport; </s> <s xml:id="echoid-s2136" xml:space="preserve">ainſi le petit triangle pourra tenir lieu du <lb/>grand.</s> <s xml:id="echoid-s2137" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div149" type="section" level="2" n="8"> <head xml:id="echoid-head115" style="it" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s2138" xml:space="preserve">9. </s> <s xml:id="echoid-s2139" xml:space="preserve">Si l’on avoit un corps F, poſé ſur un Plan incliné BC, il eſt <lb/> <anchor type="note" xlink:label="note-0117-01a" xlink:href="note-0117-01"/> conſtant que (telle que ſoit la figure de ce corps) il ne ſe main-<lb/>tiendra point en repos à moins qu’une puiſſance Q, ne le ſoûtien-<lb/>ne; </s> <s xml:id="echoid-s2140" xml:space="preserve">or ſi l’on vouloit ſavoir quel eſt le raport de la puiſſance au <lb/>poids dans la ſituation où ſe trouve cette puiſſance, il faut conſi-<lb/>derer d’abord qu’au lieu d’une puiſſance, nous en pouvons conce-<lb/>voir trois. </s> <s xml:id="echoid-s2141" xml:space="preserve">La premiere ſera la péſanteur abſoluë du corps, qui tend <lb/>au centre de la Terre ſelon une direction FG, qui, paſſant dans ſon <lb/>centre de gravité, eſt perpendiculaire à l’horiſon. </s> <s xml:id="echoid-s2142" xml:space="preserve">La ſeconde ſera <lb/>l’effort que ce corps fait ſur le Plan ſi l’on prolonge la ligne FD <lb/>juſqu’en R, on peut concevoir la ligne DR comme la direction <lb/>d’une puiſſance qui pouſſe de P en D, pour faire équilibre à l’ef-<lb/>fort que ſoûtient le Plan incliné. </s> <s xml:id="echoid-s2143" xml:space="preserve">La troiſiéme ſera la puiſſance Q, <lb/>qui empêche le corps de tomber. </s> <s xml:id="echoid-s2144" xml:space="preserve">Cela poſé, ſi l’on prolonge la li-<lb/>gne de direction GF du poids juſqu’en O, & </s> <s xml:id="echoid-s2145" xml:space="preserve">qu’on la coupe à <pb o="10" file="0118" n="121" rhead="LA SCIENCE DES INGENIEURS,"/> angles droits par ligne HI; </s> <s xml:id="echoid-s2146" xml:space="preserve">& </s> <s xml:id="echoid-s2147" xml:space="preserve">de même la direction EQ, par la <lb/>ligne IK, on aura le triangle HIK, dont le côté HK éxprimera la <lb/>puiſſance P, puiſqu’il coupe à angles droits la ligne de direction <lb/>RF; </s> <s xml:id="echoid-s2148" xml:space="preserve">le côté HI exprimera la péſanteur abſolue du poids F; </s> <s xml:id="echoid-s2149" xml:space="preserve">& </s> <s xml:id="echoid-s2150" xml:space="preserve">le <lb/>côté IK, la puiſſance Q, dans le cas où le tout ſeroit en équilibre; <lb/></s> <s xml:id="echoid-s2151" xml:space="preserve">par conſéquent on peut dire que la péſanteur abſolue du poids F, eſt <lb/>à la puiſſance Q, comme le côté HI, eſt au côté IK: </s> <s xml:id="echoid-s2152" xml:space="preserve">d’autre part la <lb/>péſanteur abſolue du poids eſt à la puiſſance Q, & </s> <s xml:id="echoid-s2153" xml:space="preserve">à l’effort que ſoû-<lb/>tient le plan incliné, ou la puiſſance P, comme HI eſt à HK; </s> <s xml:id="echoid-s2154" xml:space="preserve">ainſi <lb/>quand on connoîtra la péſanteur du poids F, & </s> <s xml:id="echoid-s2155" xml:space="preserve">le ſinus des angles <lb/>du triangle HIK, on pourra donc connoître l’effort que font les <lb/>deux puiſſances P & </s> <s xml:id="echoid-s2156" xml:space="preserve">Q.</s> <s xml:id="echoid-s2157" xml:space="preserve"/> </p> <div xml:id="echoid-div149" type="float" level="3" n="1"> <note position="right" xlink:label="note-0117-01" xlink:href="note-0117-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> <p> <s xml:id="echoid-s2158" xml:space="preserve">Il faut s’apliquer à bien entendre cette derniere Remarque rélati-<lb/>vement à ce qui a été dit dans les articles qui précédent, parce qu’elle <lb/>contribuëra beaucoup à faciliter l’intelligence de ce que nous avons <lb/>à enſeigner par la ſuite; </s> <s xml:id="echoid-s2159" xml:space="preserve">c’eſt ainſi que l’eſprit préparé à ce qu’on a <lb/>deſſein de lui inſinuer, les choſes qui lui paroiſſoient les plus com-<lb/>pliquées, lui deviennent ſenſibles dès qu’il apperçoit quelque jour <lb/>où il peut ſe reconnoître.</s> <s xml:id="echoid-s2160" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div151" type="section" level="2" n="9"> <head xml:id="echoid-head116" xml:space="preserve">CHAPITRE SECOND.</head> <head xml:id="echoid-head117" style="it" xml:space="preserve">De la maniere de calculer l’épaiſſeur de piés-droits des Voûtes <lb/>en plain ceintre, pour être en équilibre par leur réſiſtance <lb/>avec la pouſſée qu’ils ont à ſoûtenir.</head> <p> <s xml:id="echoid-s2161" xml:space="preserve">10. </s> <s xml:id="echoid-s2162" xml:space="preserve">LA neceſſité de ſe ſervir de mortier dans la conſtruction de <lb/>la maçonnerie, & </s> <s xml:id="echoid-s2163" xml:space="preserve">principalement dans celle des Voûtes, <lb/>pour lier les Pierres, fait qu’on peut ſe diſpenſer de calculer la <lb/>pouſſée de tous les vouſſoirs, chacun en particulier; </s> <s xml:id="echoid-s2164" xml:space="preserve">il ſuffit d’en <lb/>conſiderer une certaine quantité, comme ne faiſant enſemble qu’un <lb/>ſeul vouſſoir, afin d’éviter l’extrême longueur des calculs qu’on ſeroit <lb/>obligé de faire, ſi l’on en uſoit autrement; </s> <s xml:id="echoid-s2165" xml:space="preserve">car les ſujets qui ſe ra-<lb/>portent à la pratique doivent être conſiderés relativement à ce qu’ils <lb/>ſont dans l’execution, & </s> <s xml:id="echoid-s2166" xml:space="preserve">non pas tout-à-fait comme l’imagination <lb/>nous les repreſente: </s> <s xml:id="echoid-s2167" xml:space="preserve">par exemple, l’on remarque que quand les piés-<lb/>droits d’une Voûte ſont trop foibles pour en ſoûtenir la pouſſée, <lb/>la Voûte ſe fend vers le milieu des reins; </s> <s xml:id="echoid-s2168" xml:space="preserve">c’eſt-à-dire entre l’impoſte <pb o="11" file="0119" n="122" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> & </s> <s xml:id="echoid-s2169" xml:space="preserve">la clef; </s> <s xml:id="echoid-s2170" xml:space="preserve">ainſi ayant une Voûte en plain ceintre BDI, dont cha-<lb/>que quart de cercle BD & </s> <s xml:id="echoid-s2171" xml:space="preserve">DI, ſoit diviſé en deux également au point <lb/> <anchor type="note" xlink:label="note-0119-01a" xlink:href="note-0119-01"/> C & </s> <s xml:id="echoid-s2172" xml:space="preserve">H, l’experience montre que c’eſt toûjours aux endroits FC & </s> <s xml:id="echoid-s2173" xml:space="preserve"><lb/>H &</s> <s xml:id="echoid-s2174" xml:space="preserve">c. </s> <s xml:id="echoid-s2175" xml:space="preserve">que la Voûte ſe deſunit quand ſa pouſſée eſt au-deſſus de la <lb/>réſiſtance des piés-droits. </s> <s xml:id="echoid-s2176" xml:space="preserve">Or, puiſque le plus foible d’une Voûte eſt <lb/>vers le milieu des reins, il eſt donc naturel de ſupoſer que c’eſt-là <lb/>où ſe fait toute l’action de la pouſſée, & </s> <s xml:id="echoid-s2177" xml:space="preserve">de conſiderer les deux par-<lb/>ties de la Voûte CG & </s> <s xml:id="echoid-s2178" xml:space="preserve">CE, (que nous nommerons vouſſoirs) comme <lb/>ne compoſant qu’une ſeule pierre, chacune en particulier, dont l’une <lb/>CE eſt parfaitement liée avec ſon pié-droit BP, & </s> <s xml:id="echoid-s2179" xml:space="preserve">l’autre CG agit <lb/>comme un coin qui ſeroit introduit entre les deux plans FA & </s> <s xml:id="echoid-s2180" xml:space="preserve">GA <lb/>pour les ſéparer; </s> <s xml:id="echoid-s2181" xml:space="preserve">ou bien l’on pourra prendre toute la partie ſupe-<lb/>rieure CGH de la Voûte, qui tend à ſéparer comme un coin les deux <lb/>Plans AF & </s> <s xml:id="echoid-s2182" xml:space="preserve">A &</s> <s xml:id="echoid-s2183" xml:space="preserve">c. </s> <s xml:id="echoid-s2184" xml:space="preserve">& </s> <s xml:id="echoid-s2185" xml:space="preserve">dans ce ſens, ce ſera cette partie qui cauſera <lb/>toute la pouſſée; </s> <s xml:id="echoid-s2186" xml:space="preserve">la moitié CG agira pour écarter le corps P FCS, <lb/>(compoſé du pié-droit PB & </s> <s xml:id="echoid-s2187" xml:space="preserve">du vouſſoir EC, comme je l’ai inſi-<lb/>nué d’abord) & </s> <s xml:id="echoid-s2188" xml:space="preserve">alors il ſuffira pour calculer cette pouſſée de n’a-<lb/>voir égard qu’à la moitié de la Voûte depuis le point d’apui P, juſ-<lb/>qu’au ſommet DG, puiſque l’on concevra la même choſe pour l’au-<lb/>tre moitié.</s> <s xml:id="echoid-s2189" xml:space="preserve"/> </p> <div xml:id="echoid-div151" type="float" level="3" n="1"> <note position="right" xlink:label="note-0119-01" xlink:href="note-0119-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <p> <s xml:id="echoid-s2190" xml:space="preserve">Conſidérant le vouſſoir ſupérieur FD, comme n’ayant aucune <lb/>liaiſon avec le reſte de la maçonnerie, la pouſſée qui ſe fera à l’é-<lb/>gard du point d’apui P, ſera la plus grande qu’il eſt poſſible; </s> <s xml:id="echoid-s2191" xml:space="preserve">puiſ-<lb/>que dans une Voûte il n’arrive jamais que les vouſſoirs agiſſent <lb/>auſſi puiſſamment qu’ils feroient ſi leurs joints étoient extrêmement <lb/>polis, ſans trouver d’obſtacle de la part du mortier ni du frotement: <lb/></s> <s xml:id="echoid-s2192" xml:space="preserve">par conſéquent ſi l’on cherche à proportionner la réſiſtance du pié-<lb/>droit P B à cette plus grande pouſſée, on donnera à la puiſſance <lb/>réſiſtante une force un peu au-deſſus de celle qu’il lui faudroit effec-<lb/>tivement pour ſoûtenir l’effort du vouſſoir FD, dans le cas où il <lb/>ſeroit lié avec le reſte de la Voûte; </s> <s xml:id="echoid-s2193" xml:space="preserve">ainſi cette ſupoſition ne pou-<lb/>vant que contribuer à la fermeté des piés-droits, il s’enſuit que <lb/>conſidérer ici les choſes dans la rigueur de la Théorie, c’eſt leur <lb/>donner tout l’avantage qu’on peut déſirer dans la pratique.</s> <s xml:id="echoid-s2194" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2195" xml:space="preserve">Cela poſé, ſi l’on éleve une perpendiculaire LO ſur le milieu du <lb/>joint FC, cette perpendiculaire exprimera la direction de la puiſ-<lb/>ſance qui ſoûtiendroit l’effort que fait le vouſſoir FD, ſur le plan <lb/>incliné F A <anchor type="note" xlink:href="" symbol="*"/>; </s> <s xml:id="echoid-s2196" xml:space="preserve">de même ſi ſur le milieu du joint GD on éleve une <anchor type="note" xlink:label="note-0119-02a" xlink:href="note-0119-02"/> autre perpendiculaire HW, elle exprimera auſſi la direction de la <lb/>puiſſance qui ſoûtiendroit l’effort que feroit le vouſſoir contre le <lb/>Plan vertical G A: </s> <s xml:id="echoid-s2197" xml:space="preserve">enfin ſi du point X, (que je ſupoſe le centre <pb o="12" file="0120" n="123" rhead="LA SCIENCE DES INGENIEURS,"/> de gravité du vouſſoir) on abaiſſe une perpendiculaire XR à l’ho-<lb/>riſon, elle exprimera la direction, ſuivant laquelle ce vouſſoir tend <lb/>au centre de la Terre <anchor type="note" xlink:href="" symbol="*"/>, par conſéquent nous avons ici trois puiſ- <anchor type="note" xlink:label="note-0120-01a" xlink:href="note-0120-01"/> ſances, qui dans l’état d’équilibre ſeront exprimées par les trois <lb/>côtés du triangle rectangle ALK <anchor type="note" xlink:href="" symbol="*"/>, car le côté LK, étant perpen- <anchor type="note" xlink:label="note-0120-02a" xlink:href="note-0120-02"/> diculaire ſur la direction XR exprimera la péſanteur abſoluë du <lb/>vouſſoir FD; </s> <s xml:id="echoid-s2198" xml:space="preserve">de même le côté LA étant perpendiculaire ſur la di-<lb/>rection LO de la puiſſance O, il exprimera la force de cette puiſ-<lb/>ſance pour ſoûtenir la pouſſée qui ſe fait ſur le joint FC; </s> <s xml:id="echoid-s2199" xml:space="preserve">enfin la <lb/>direction HW de la puiſſance W, étant perpendiculaire ſur la ligne <lb/>GA, le côté KA exprimera l’effort de cette puiſſance; </s> <s xml:id="echoid-s2200" xml:space="preserve">mais com-<lb/>me elle n’entre point ici dans le calcul, nous en ferons abſtraction <lb/>à l’avenir, pour ne conſidérer que la ſeule puiſſance O, dont le bras <lb/>de lévier ſera exprimé par la perpendiculaire PO, tirée du point d’a-<lb/>pui P ſur la direction LO: </s> <s xml:id="echoid-s2201" xml:space="preserve">prévenu de tout ceci, je ne crois pas <lb/>qu’on rencontre aucune difficulté à bien entendre les propoſitions <lb/>qui vont faire l’objet de ce Chapitre.</s> <s xml:id="echoid-s2202" xml:space="preserve"/> </p> <div xml:id="echoid-div152" type="float" level="3" n="2"> <note symbol="*" position="right" xlink:label="note-0119-02" xlink:href="note-0119-02a" xml:space="preserve">Art. 1.</note> <note symbol="*" position="left" xlink:label="note-0120-01" xlink:href="note-0120-01a" xml:space="preserve">Art. 9.</note> <note symbol="*" position="left" xlink:label="note-0120-02" xlink:href="note-0120-02a" xml:space="preserve">Art. 2. <lb/>& 3.</note> </div> </div> <div xml:id="echoid-div154" type="section" level="2" n="10"> <head xml:id="echoid-head118" xml:space="preserve">PROPOSITION PREMIERE.</head> <head xml:id="echoid-head119" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <head xml:id="echoid-head120" style="it" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux piés-droits des <lb/>Voûtes en plain ceintre, pour être en équilibre par leur réſiſ-<lb/>tance avec la pouſſée qu’ils ont à ſoûtenir.</head> <p> <s xml:id="echoid-s2203" xml:space="preserve">11. </s> <s xml:id="echoid-s2204" xml:space="preserve">Ayant mené par le point L milieu de FC, la ligne MK pa-<lb/>ralelle à ZA, & </s> <s xml:id="echoid-s2205" xml:space="preserve">prolongé PZ juſqu’en M, & </s> <s xml:id="echoid-s2206" xml:space="preserve">abaiſſé la perpendi-<lb/> <anchor type="note" xlink:label="note-0120-03a" xlink:href="note-0120-03"/> culaire LV ſur AB, nous nommerons LK, ou KA, a, LA, b; </s> <s xml:id="echoid-s2207" xml:space="preserve">BV, <lb/>c; </s> <s xml:id="echoid-s2208" xml:space="preserve">ZP, d; </s> <s xml:id="echoid-s2209" xml:space="preserve">ZB ou P S, y; </s> <s xml:id="echoid-s2210" xml:space="preserve">ainſi ML ou MN, ſera y + c, & </s> <s xml:id="echoid-s2211" xml:space="preserve">MP ſera <lb/>a + d, par conſéquent NP ſera a + d - c - y; </s> <s xml:id="echoid-s2212" xml:space="preserve">& </s> <s xml:id="echoid-s2213" xml:space="preserve">ſi l’on ſupoſe <lb/>a + d - c = f, l’on aura f - y, pour la valeur de NP: </s> <s xml:id="echoid-s2214" xml:space="preserve">la ſuperficie <lb/>de chaque vouſſoir CG & </s> <s xml:id="echoid-s2215" xml:space="preserve">CE, ſera nommée nn; </s> <s xml:id="echoid-s2216" xml:space="preserve">enfin ſi du centre <lb/>de gravité Q, du vouſſoir CE, l’on abaiſſe la perpendiculaire QR, <lb/>ſur la baſe PS, RS ſera nommé g; </s> <s xml:id="echoid-s2217" xml:space="preserve">par conſequent P R ſera y - g.</s> <s xml:id="echoid-s2218" xml:space="preserve"/> </p> <div xml:id="echoid-div154" type="float" level="3" n="1"> <note position="left" xlink:label="note-0120-03" xlink:href="note-0120-03a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <p> <s xml:id="echoid-s2219" xml:space="preserve">Cela poſé, la premiere choſe qu’il faut chercher eſt l’expreſſion <lb/>du bras de lévier PO; </s> <s xml:id="echoid-s2220" xml:space="preserve">pour cela conſiderés que les triangles LKA <lb/>& </s> <s xml:id="echoid-s2221" xml:space="preserve">NOP, ſont ſemblables, puiſqu’ils ſont rectangles & </s> <s xml:id="echoid-s2222" xml:space="preserve">izocelles, & </s> <s xml:id="echoid-s2223" xml:space="preserve"><lb/>que par conſéquent LA (b). </s> <s xml:id="echoid-s2224" xml:space="preserve">LK (a):</s> <s xml:id="echoid-s2225" xml:space="preserve">: NP (f - y.) </s> <s xml:id="echoid-s2226" xml:space="preserve">PO {(af - ay)/b}. <lb/></s> <s xml:id="echoid-s2227" xml:space="preserve">D’un autre côté remarquez que la péſanteur abſolue du vouſſoir ED <pb o="13" file="0121" n="124" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> eſt à l’effort que ſoûtient le joint FC, ou la puiſſance O, comme <lb/>LK eſt à -3.</s> <s xml:id="echoid-s2228" xml:space="preserve">0<anchor type="note" xlink:href="" symbol="*"/>, ou bien, ab : </s> <s xml:id="echoid-s2229" xml:space="preserve">: </s> <s xml:id="echoid-s2230" xml:space="preserve">nn. </s> <s xml:id="echoid-s2231" xml:space="preserve">{bnn/a}: </s> <s xml:id="echoid-s2232" xml:space="preserve">ainſi multipliant {bnn/a} (qui eſt <anchor type="note" xlink:label="note-0121-01a" xlink:href="note-0121-01"/> l’expreſſion de la puiſſance O) par ſon bras de lévier PO, l’on aura <lb/>nnf-nny pour la pouſſée de la Voûte par raport au point d’apui P; <lb/></s> <s xml:id="echoid-s2233" xml:space="preserve">& </s> <s xml:id="echoid-s2234" xml:space="preserve">comme nous voulons mettre cette pouſſée en équilibre avec la <lb/>réſiſtance du pié-droit joint au vouſſoir EC, il faut multiplier la ſu-<lb/>perficie du rectangle PB qui eſt d y, par le bras de lévier PT({y/2}) <lb/>moitié de PS pour avoir {dyy/2}; </s> <s xml:id="echoid-s2235" xml:space="preserve">& </s> <s xml:id="echoid-s2236" xml:space="preserve">comme nous avons encore le <lb/>vouſſoir EC, dont la ligne de direction QR, tirée du centre de gra-<lb/>vité perpendiculaire ſur PS marque que PR (y-g) eſt le bras de <lb/>lévier qui répond à l’action de ce vouſſoir, il faut donc multiplier <lb/>nn par y-g pour avoir nny-nng, qui étant ajoûté avec {dyy/2}, donnera <lb/>une expreſſion égale à la puiſſance réſiſtante; </s> <s xml:id="echoid-s2237" xml:space="preserve">par conſéquent l’on <lb/>a cette équation nnf-nny={dyy/2}+nny-nng, d’où faiſant paſſer <lb/>du premier membre dans le ſecond, le terme où ſe trouvera l’in-<lb/>connu, & </s> <s xml:id="echoid-s2238" xml:space="preserve">du ſecond dans le premier, le terme où l’inconnu ne <lb/>ſe trouve point, l’on aura après avoir multiplié par 2 & </s> <s xml:id="echoid-s2239" xml:space="preserve">diviſé par d, <lb/>{2nnf+2nng/d}=yy+{4nny/d}, qui eſt une équation dont il ſera aiſé d’a-<lb/>voir la valeur de l’inconnu, en ajoûtant à chaque membre le quarré <lb/>de la moitié du coëficient du ſecond terme, afin de rendre le ſecond <lb/>membre un quarré parfait; </s> <s xml:id="echoid-s2240" xml:space="preserve">& </s> <s xml:id="echoid-s2241" xml:space="preserve">alors il viendra {2nnf+2nng/d}+{4n4/dd} <lb/>=yy+{4nny/d}+{4n4/dd}, dont extrayant la racine quarrée & </s> <s xml:id="echoid-s2242" xml:space="preserve">déga-<lb/>geant l’inconnu, il vient √2nnf+2nng/d+4n4/dd\x{0020}-{2nn/d}=y.</s> <s xml:id="echoid-s2243" xml:space="preserve"/> </p> <div xml:id="echoid-div155" type="float" level="3" n="2"> <note symbol="*" position="foot" xlink:label="note-0121-01" xlink:href="note-0121-01a" xml:space="preserve">Art. 4</note> </div> </div> <div xml:id="echoid-div157" type="section" level="2" n="11"> <head xml:id="echoid-head121" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s2244" xml:space="preserve">Quand on eſt une fois parvenu à trouver une expreſſion qui don-<lb/>ne la valeur de l’inconnu, il n’y a plus qu’à faire par les nombres <lb/>ce que la derniere équation nous a indiqué; </s> <s xml:id="echoid-s2245" xml:space="preserve">cependant comme les <lb/>calculs, tout aiſés qu’ils ſont, pourroient embarraſſer ceux quin’en <lb/>ont point l’habitude, je vais, comme dans le Livre précédent, en <lb/>détailler les opérations.</s> <s xml:id="echoid-s2246" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2247" xml:space="preserve">Nous ſupoſerons que le rayon AB eſt de 12 pieds; </s> <s xml:id="echoid-s2248" xml:space="preserve">que le rayon <pb o="14" file="0122" n="125" rhead="LA SCIENCE DES INGENIEURS,"/> AE eſt de 15; </s> <s xml:id="echoid-s2249" xml:space="preserve">par conſéquent la Voûte en aura 3 d’épaiſſeur: <lb/></s> <s xml:id="echoid-s2250" xml:space="preserve">ainſi AL (b) ſera de 13 pieds 6 pouces, LK ou KA (a) de 9 pieds <lb/>10 pouces, & </s> <s xml:id="echoid-s2251" xml:space="preserve">BV (c) ſera de 2 pieds 2 pouces; </s> <s xml:id="echoid-s2252" xml:space="preserve">nous ſupo-<lb/>ſerons auſſi que ZP (d) ou la hauteur des piés-droits eſt de 15 <lb/>pieds, & </s> <s xml:id="echoid-s2253" xml:space="preserve">que RS (g) eſt d’un pied; </s> <s xml:id="echoid-s2254" xml:space="preserve">& </s> <s xml:id="echoid-s2255" xml:space="preserve">ſelon toutes ces ſupoſitions <lb/>a+d-c=f ſera de 22 pieds 2 pouces: </s> <s xml:id="echoid-s2256" xml:space="preserve">de ſorte que f+g ſera <lb/>23 pieds 2 pouces; </s> <s xml:id="echoid-s2257" xml:space="preserve">or comme il ne nous reſte plus que de con-<lb/>noître nn, il n’y a qu’à chercher la ſuperficie des deux cercles qui <lb/>auroient pour rayons AC & </s> <s xml:id="echoid-s2258" xml:space="preserve">AF; </s> <s xml:id="echoid-s2259" xml:space="preserve">c’eſt-à-dire, 12 & </s> <s xml:id="echoid-s2260" xml:space="preserve">15 pieds, ôter la <lb/>plus petite de la plus grande, & </s> <s xml:id="echoid-s2261" xml:space="preserve">prendre la huitiéme partie de la <lb/>différence qu’on trouvera d’environ 32 pieds, qui ſera la valeur de <lb/>nn; </s> <s xml:id="echoid-s2262" xml:space="preserve">c’eſt-à-dire, de chaque vouſſoir CG ou CE. </s> <s xml:id="echoid-s2263" xml:space="preserve">Preſentement que <lb/>l’on connoît la valeur de toutes les lettres, il ne s’agit plus que de <lb/>faire les mêmes opérations que celles qui ſont indiquées dans l’é-<lb/>quation √2nnf+2nng/d+4nn4/dd\x{0020}-{2nn/d}=y, dans laquelle je re-<lb/>marque que f+g eſt multiplié par 2nn. </s> <s xml:id="echoid-s2264" xml:space="preserve">Or comme f+g vaut 23 <lb/>pieds 2 pouces, & </s> <s xml:id="echoid-s2265" xml:space="preserve">nn, 23 pieds dont le double eſt 64, je multi-<lb/>plie donc 64 par 23 pieds 2 pouces, & </s> <s xml:id="echoid-s2266" xml:space="preserve">je diviſe le produit par la <lb/>valeur de d, qui eſt 15, & </s> <s xml:id="echoid-s2267" xml:space="preserve">le quotient donne 98 pieds 10 pouces: </s> <s xml:id="echoid-s2268" xml:space="preserve"><lb/>enſuite je remarque que le troiſiéme terme de mon équation eſt le <lb/>quarré de {2nn/d}; </s> <s xml:id="echoid-s2269" xml:space="preserve">c’eſt-à-dire, de 64 diviſé par 15, qui donne 18, <lb/>qui étant ajoûté avec 98 pieds 10 pouces, l’on aura 116 pieds 10 <lb/>pouces, dont il faut extraire la racine quarrée que l’on trouvera <lb/>de 10 pieds 9 pouces 7 lignes; </s> <s xml:id="echoid-s2270" xml:space="preserve">mais comme l’on voit dans l’équa-<lb/>tion qu’il faut ôter de cette racine {2nn/d}, il faudra donc ſouſtraire ſa <lb/>valeur, c’eſt-à-dire, 4 pieds 3 pouces de 10 pieds 9 pouces 7 li-<lb/>gnes, & </s> <s xml:id="echoid-s2271" xml:space="preserve">la différence qui eſt 6 pieds 6 pouces 7 lignes, ſera la va-<lb/>leur de y; </s> <s xml:id="echoid-s2272" xml:space="preserve">c’eſt-à-dire, l’épaiſſeur PS qu’il faudra donner aux piés-<lb/>droits de la Voûte dont il s’agit pour être en équilibre avec la <lb/>pouſſée.</s> <s xml:id="echoid-s2273" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2274" xml:space="preserve">On prendra garde que l’épaiſſeur que l’on vient de trouver n’eſt <lb/>pas celle que je prétend qu’il faut donner au pié-droit d’une Voûte <lb/>qui auroit les mêmes dimenſions que celle qu’on a ſupoſée ici, puiſ-<lb/>qu’après avoir trouvé le point d’équilibre, il faut, comme on l’a dit <lb/>pluſieurs fois dans le Livre précédent, mettre toûjours la puiſſance <lb/>réſiſtante au-deſſus de la pouſſée, afin d’agir en toute ſeureté, ce <lb/>qui ſe fera en donnant au pié-droit 5 ou 6 pouces d’épaiſſeur de <lb/>plus que n’en demande le calcul, ou bien en ajoûtant des contreforts <lb/>comme nous en ferons mention ailleurs.</s> <s xml:id="echoid-s2275" xml:space="preserve"/> </p> <pb o="15" file="0123" n="126" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div158" type="section" level="2" n="12"> <head xml:id="echoid-head122" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s2276" xml:space="preserve">12. </s> <s xml:id="echoid-s2277" xml:space="preserve">Quand on a trouvé une expreſſion Algebrique qui marque <lb/>la pouſſée d’une Voûte, il eſt facile de réſoudre pluſieurs cas qu’on <lb/> <anchor type="note" xlink:label="note-0123-01a" xlink:href="note-0123-01"/> peut propoſer au ſujet des Bâtimens dans leſquels on doit faire des <lb/>Voûtes: </s> <s xml:id="echoid-s2278" xml:space="preserve">en voici un autre qui ſe rencontre fort ſouvent.</s> <s xml:id="echoid-s2279" xml:space="preserve"/> </p> <div xml:id="echoid-div158" type="float" level="3" n="1"> <note position="right" xlink:label="note-0123-01" xlink:href="note-0123-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> <p> <s xml:id="echoid-s2280" xml:space="preserve">On a deſſein de faire une Voùte ELM élévée ſur despiés-droits <lb/>EA & </s> <s xml:id="echoid-s2281" xml:space="preserve">MN, & </s> <s xml:id="echoid-s2282" xml:space="preserve">l’on veut faire au-deſſus de la Voûte un Bâtiment, <lb/>ſoit pour la couvrir contre les injures du tems, ou pour y pratiquer <lb/>quelque logement, ainſi qu’on le fait au-deſſus du paſſage des Portes <lb/>des Villes; </s> <s xml:id="echoid-s2283" xml:space="preserve">pour cela on ſera obligé d’élever à droit & </s> <s xml:id="echoid-s2284" xml:space="preserve">à gauche deux <lb/>pignons IG & </s> <s xml:id="echoid-s2285" xml:space="preserve">OP ſur les piés-droits, qui, étant chargés de ces deux <lb/>nouveaux corps de Maçonnerie, n’auront pas beſoin de tant d’é-<lb/>paiſſeur que s’ils n’avoient que leur hauteur naturelle; </s> <s xml:id="echoid-s2286" xml:space="preserve">on demande <lb/>donc (étant prévenu de la hauteur IF & </s> <s xml:id="echoid-s2287" xml:space="preserve">de l’épaiſſeur IK, que doi-<lb/>vent avoir les murs qu’on veut élever en même tems que les piés-<lb/>droits) qu’elle doit être l’épaiſſeur AB, pour que le tout ſoit en <lb/>équilibre?</s> <s xml:id="echoid-s2288" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2289" xml:space="preserve">Nous ſupoſerons pour plus de facilité, que le mur IG fera élevé <lb/>ſur le milieu du pié-droit; </s> <s xml:id="echoid-s2290" xml:space="preserve">enſorte que les centres de gravité H & </s> <s xml:id="echoid-s2291" xml:space="preserve"><lb/>Q des deux murs IG & </s> <s xml:id="echoid-s2292" xml:space="preserve">DB ſoient dans la même ligne HC qui tombe <lb/>ſur le mileu de AB, & </s> <s xml:id="echoid-s2293" xml:space="preserve">que la Voûte dont il eſt queſtion a les <lb/>mêmes dimenſions que cy-devant, & </s> <s xml:id="echoid-s2294" xml:space="preserve">nommées par les mêmes Let-<lb/>tres: </s> <s xml:id="echoid-s2295" xml:space="preserve">cela poſé, il eſt certain que ſi on ne faiſoit pas mention comme <lb/>dans la figure précédente du mur IG, la réſiſtance du pié-droit <lb/>ſeroit exprimée par {dyy/2}+nny-nng; </s> <s xml:id="echoid-s2296" xml:space="preserve">mais comme il faut y ajoû-<lb/>ter le poids de ce mur, multiplié par le bras de lévier AC, ſi on nom-<lb/>me IF, h; </s> <s xml:id="echoid-s2297" xml:space="preserve">& </s> <s xml:id="echoid-s2298" xml:space="preserve">IK, r; </s> <s xml:id="echoid-s2299" xml:space="preserve">l’on aura donc {dyy/2}+nny+{bry/2}-nng pour <lb/>la réſiſtance d’un pié-droit de la Voûte qui devant être en équilibre <lb/>avec la pouſſée, par conſéquent cette équation {ddy/2}+nny+{bry/2} <lb/>-nng=nnf-nny, qui ne differe de celle que nous avons vûe ci-<lb/>devant que de ſeul terme {bry/2}; </s> <s xml:id="echoid-s2300" xml:space="preserve">c’eſt pourquoi faiſant les mêmes <lb/>choſes qu’on a déja faites pour dégager l’inconnu, & </s> <s xml:id="echoid-s2301" xml:space="preserve">pour en avoir <lb/>la valeur en nombre, l’on trouvera en déterminant les dimenſions <lb/>h&</s> <s xml:id="echoid-s2302" xml:space="preserve">r; </s> <s xml:id="echoid-s2303" xml:space="preserve">combien il faudra donner de moins à l’épaiſſeur des piés-droits <lb/>que dans le cas précédent.</s> <s xml:id="echoid-s2304" xml:space="preserve"/> </p> <pb o="16" file="0124" n="127" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div160" type="section" level="2" n="13"> <head xml:id="echoid-head123" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s2305" xml:space="preserve">13. </s> <s xml:id="echoid-s2306" xml:space="preserve">Nous venons de ſupoſer que l’extradoſe de la Voûte, ſur la-<lb/>quelle nous avons operé, étoit circulaire, parce qu’il s’en rencontre <lb/>qui ont cette figure; </s> <s xml:id="echoid-s2307" xml:space="preserve">mais comme dans les Places de Guerre les <lb/>Voûtes des ſouterrains & </s> <s xml:id="echoid-s2308" xml:space="preserve">celles des Magaſins à poudre ont toûjours <lb/>leurs extradoſes terminés en dos d’âne, pour l’écoulement des eaux de <lb/> <anchor type="note" xlink:label="note-0124-01a" xlink:href="note-0124-01"/> pluye, & </s> <s xml:id="echoid-s2309" xml:space="preserve">pour qu’elles réſiſtent mieux en tems de Siége au choc <lb/>des bombes, il eſt bon de nous arrêter ici un moment pour faire <lb/>voir qu’on trouvera l’épaiſſeur des piés-droits de ces ſortes de Voûtes <lb/>de la même maniere que dans le Probléme précédent.</s> <s xml:id="echoid-s2310" xml:space="preserve"/> </p> <div xml:id="echoid-div160" type="float" level="3" n="1"> <note position="left" xlink:label="note-0124-01" xlink:href="note-0124-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 10.</note> </div> <p> <s xml:id="echoid-s2311" xml:space="preserve">Prenant pour exemple le Profil d’un Magaſin à Poudre, il faut <lb/>être prévenu que pour mettre ces ſortes d’édifices à l’épreuve de <lb/>la Bombe, on donne ordinairement à la Voûte 3 pieds d’épaiſſeur <lb/>au milieu des reins; </s> <s xml:id="echoid-s2312" xml:space="preserve">c’eſt-à-dire, qu’ayant diviſé le quart de cercle <lb/>BD, en deux également au point C, on prolonge le rayon AC, juſ-<lb/>qu’en F, enſorte que CF, ſoit de 3 pieds: </s> <s xml:id="echoid-s2313" xml:space="preserve">& </s> <s xml:id="echoid-s2314" xml:space="preserve">afin de bien diriger <lb/>les pantes GH, & </s> <s xml:id="echoid-s2315" xml:space="preserve">GI, on les fait perpendiculaires ſur le rayon AF, <lb/>& </s> <s xml:id="echoid-s2316" xml:space="preserve">alors elles forment un angle droit HGI, au ſommet, qui eſt l’an-<lb/>gle qui convient le mieux pour ne point rendre le Magaſin trop <lb/>élevé ni trop écraſé.</s> <s xml:id="echoid-s2317" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2318" xml:space="preserve">Cela poſé, ſi l’on ſupoſe le rayon AB, de 12 pieds; </s> <s xml:id="echoid-s2319" xml:space="preserve">la ligne AF, <lb/>de 15; </s> <s xml:id="echoid-s2320" xml:space="preserve">& </s> <s xml:id="echoid-s2321" xml:space="preserve">la hauteur du pié-droit ZP auſſi de 15, nous aurons les <lb/>mêmes lignes que ci-devant, & </s> <s xml:id="echoid-s2322" xml:space="preserve">chacune ſera exprimée par les mê-<lb/>mes lettres & </s> <s xml:id="echoid-s2323" xml:space="preserve">les mêmes nombres, & </s> <s xml:id="echoid-s2324" xml:space="preserve">il n’y aura que les deux parties <lb/>égales CFGD & </s> <s xml:id="echoid-s2325" xml:space="preserve">CFHB de la Voûte qui ſeront differentes, étant <lb/>beaucoup plus conſidérables: </s> <s xml:id="echoid-s2326" xml:space="preserve">ce qui changera la valeur de nn.</s> <s xml:id="echoid-s2327" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2328" xml:space="preserve">Les triangles LKA & </s> <s xml:id="echoid-s2329" xml:space="preserve">NOP, étant enſemble, l’on aura LA (b) <lb/>LK (a) : </s> <s xml:id="echoid-s2330" xml:space="preserve">: </s> <s xml:id="echoid-s2331" xml:space="preserve">NP (f-y). </s> <s xml:id="echoid-s2332" xml:space="preserve">PO ({af-ay/b)} & </s> <s xml:id="echoid-s2333" xml:space="preserve">comme la partie CFGD <lb/>de la Voûte agit toûjours ſur le joint FC ou ſur la puiſſance O, dont <lb/>la direction OL eſt perpendiculaire ſur le milieu du joint FC, l’ex-<lb/>preſſion de cette puiſſance ſera encore {nnb/a}, laquelle étant multi-<lb/>pliée par ſon bras de lévier PO, il vient nnf-nny pour la pouſſée <lb/>de la Voûte par raport au point d’apui P.</s> <s xml:id="echoid-s2334" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2335" xml:space="preserve">D’un autre côté la réſiſtance du pié-droit ſera le produit de ſa ſu-<lb/>perficie par la moitié de la baſe PS, qui donne {dyy/2}, à quoi ajoûtant <lb/>le produit de la ſuperficie de la partie CFHB par ſon bras de lévier <lb/>PR (y-g) l’on aura {dyy/2}+nny-nng pour l’expreſſion de la <pb o="17" file="0125" n="128" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> puiſſance réſiſtante; </s> <s xml:id="echoid-s2336" xml:space="preserve">par conſéquent cette équation nnf-nny <lb/>={dyy/2}+nny-nng, qui étant la même que celle qu’on a trouvée <lb/>dans la propoſition précédente, ſe réduira à √2nnf+2nng/d+{4n+/dd}\x{0020} <lb/>-{2nn/d}=y, qui donnera la valeur de l’inconnu en ſuivant ce qui <lb/>a été enſeigné dans l’aplication.</s> <s xml:id="echoid-s2337" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2338" xml:space="preserve">On remarquera, comme je l’ai déja dit, qu’il faudra chercher une <lb/>nouvelle valeur de nn, ce qui eſt bien aiſé; </s> <s xml:id="echoid-s2339" xml:space="preserve">car comme l’on con-<lb/>noît les côtés AF & </s> <s xml:id="echoid-s2340" xml:space="preserve">FG, du triangle rectangle FGA, auſſi-bien que <lb/>le rayon AC, on n’aura qu’à retrancher le ſecteur ACD, du trian-<lb/>gle, la difference ſera la valeur de la partie CFGD, ou de nn, que <lb/>l’on trouvera de 56 pieds.</s> <s xml:id="echoid-s2341" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2342" xml:space="preserve">On prendra garde auſſi que la partie FHBC, de la Voûte qui eſt <lb/>une avec le pié-droit étant d’une figure différente que dans le Pro-<lb/>bléme précédent, le centre de gravité Q, ne ſera point dans la mê-<lb/>me poſition par raport à la baſe PS, puiſque la ligne RS, ſera né-<lb/>ceſſairement plus grande que dans la figure 7. </s> <s xml:id="echoid-s2343" xml:space="preserve">ce qui fait que la va-<lb/>leur de g, ne peut être d’un pied comme nous l’avons ſupoſé ci-<lb/>devant; </s> <s xml:id="echoid-s2344" xml:space="preserve">auſſi l’ai-je eſtimé de 18 pouces: </s> <s xml:id="echoid-s2345" xml:space="preserve">or ſi l’on a égard à tout <lb/>ce que je viens de dire, on trouvera en faiſant le calcul numeri-<lb/>que que l’épaiſſeur PS, des piés-droits doit être de 7 pied 8 pou-<lb/>ces 6 lignes dans l’état d’équilibre.</s> <s xml:id="echoid-s2346" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div162" type="section" level="2" n="14"> <head xml:id="echoid-head124" style="it" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s2347" xml:space="preserve">14. </s> <s xml:id="echoid-s2348" xml:space="preserve">Mais ſi l’on avoit une Voûte BDH, dont le deſſus fut ter-<lb/>miné par un Plan horizontal QX, il eſt conſtant que prolongeant <lb/> <anchor type="note" xlink:label="note-0125-01a" xlink:href="note-0125-01"/> les rayons AC & </s> <s xml:id="echoid-s2349" xml:space="preserve">Ar, (qui diviſent les quarts de cercles DB & </s> <s xml:id="echoid-s2350" xml:space="preserve"><lb/>DH, en deux également juſqu’à la rencontre de la ligne QX) la <lb/>partie ſuperieure CWIrD, de la Voûte exercera toute la pouſſée <lb/>que doivent ſoûtenir les piés-droits: </s> <s xml:id="echoid-s2351" xml:space="preserve">or voulant ſavoir l’épaiſſeur <lb/>qu’il faut leur donner, je prolonge SB juſqu’en R, & </s> <s xml:id="echoid-s2352" xml:space="preserve">conſidere le <lb/>rectangle PQRS, comme le pié-droit qui répond au vouſſoir OWGD; <lb/></s> <s xml:id="echoid-s2353" xml:space="preserve">mais, dira-t’on, ce vouſſoir anticipe ſur le pié-droit de tout le trian-<lb/>gle FWR, par conſéquent le pié-droit a plus de ſuperficie qu’il ne <lb/>devroit avoir: </s> <s xml:id="echoid-s2354" xml:space="preserve">cela eſt vrai; </s> <s xml:id="echoid-s2355" xml:space="preserve">mais auſſi je compte de faire abſtrac-<lb/>tion du triangle mixte BFC, qui apartient naturellement au pié-<lb/>droit, afin d’éviter les petites circonſtances qui pourroient rendre le <lb/>Probléme embarraſſant: </s> <s xml:id="echoid-s2356" xml:space="preserve">ainſi pour le ramener à la propoſition pré- <pb o="18" file="0126" n="129" rhead="LA SCIENCE DES INGENIEURS,"/> cédente, je prends la partie CF égale à DG, & </s> <s xml:id="echoid-s2357" xml:space="preserve">j’éléve ſur ſon mi-<lb/>lieu L la perpendiculaire LO, pour marquer la direction de la puiſ-<lb/>ſance O, & </s> <s xml:id="echoid-s2358" xml:space="preserve">je tire les lignes MK & </s> <s xml:id="echoid-s2359" xml:space="preserve">LV comme ci-devant, & </s> <s xml:id="echoid-s2360" xml:space="preserve">les <lb/>nomme auſſi-bien que les autres par les mêmes lettres dont on s’eſt <lb/>déja ſervi, excepté MP que nous nommerons f: </s> <s xml:id="echoid-s2361" xml:space="preserve">cela poſé, remar-<lb/>quez que les triangles ſemblables LKA & </s> <s xml:id="echoid-s2362" xml:space="preserve">PON donne LA (b). <lb/></s> <s xml:id="echoid-s2363" xml:space="preserve">LK (a) :</s> <s xml:id="echoid-s2364" xml:space="preserve">: PN (f - c - y). </s> <s xml:id="echoid-s2365" xml:space="preserve">PO ({af - ac - ay/b}), & </s> <s xml:id="echoid-s2366" xml:space="preserve">que la pé-<lb/>ſanteur abſoluë du vouſſoir CWGD (nn) eſt encore à la pouſſée, <lb/>ou ſi l’on veut à l’effort de la puiſſance O, comme LK (a) eſt à <lb/>LA (b); </s> <s xml:id="echoid-s2367" xml:space="preserve">ce qui donne toûjours{nnb/a} pour l’expreſſion de cette <lb/>puiſſance, qui étant multipliée par ſon bras de lévier PO, l’on aura <lb/>fnn - cnn - ynn, pour le produit qui doit être égal dans l’état d’é-<lb/>quilibre à la péſanteur du pié-droit PQRS, multiplié par ſon bras de <lb/>lévier PT; </s> <s xml:id="echoid-s2368" xml:space="preserve">ainſi ayant nommé QP, d; </s> <s xml:id="echoid-s2369" xml:space="preserve">& </s> <s xml:id="echoid-s2370" xml:space="preserve">PS, y; </s> <s xml:id="echoid-s2371" xml:space="preserve">l’on aura {dyy/2} <lb/>pour la réſiſtance du pié-droit, par conſéquent cette équation <lb/>fnn - cnn - ynn = {dyy/2}, qui étant multiplié par 2, & </s> <s xml:id="echoid-s2372" xml:space="preserve">diviſé par d, <lb/>donne 2fnn - 2cnn = yy + {2nny/d}, de laquelle dégageant l’inconnu, <lb/>il vient {√2fnn - 2cnn\x{0020}/d} + {√n4\x{0020}/dd} - {nn/d} = y.</s> <s xml:id="echoid-s2373" xml:space="preserve"/> </p> <div xml:id="echoid-div162" type="float" level="3" n="1"> <note position="right" xlink:label="note-0125-01" xlink:href="note-0125-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 11.</note> </div> <p> <s xml:id="echoid-s2374" xml:space="preserve">Si l’on ſupoſe préſentement le rayon AB de 12 pieds; </s> <s xml:id="echoid-s2375" xml:space="preserve">GD, de <lb/>3; </s> <s xml:id="echoid-s2376" xml:space="preserve">BS, de 15; </s> <s xml:id="echoid-s2377" xml:space="preserve">QP (d) ſera de 30; </s> <s xml:id="echoid-s2378" xml:space="preserve">LK ou LV (a) ſera de 9 pieds <lb/>10 pouces; </s> <s xml:id="echoid-s2379" xml:space="preserve">MP (f) de 24 pieds 10 pouces; </s> <s xml:id="echoid-s2380" xml:space="preserve">BV (c) de 2 pieds 2 <lb/>pouces; </s> <s xml:id="echoid-s2381" xml:space="preserve">& </s> <s xml:id="echoid-s2382" xml:space="preserve">nn ſera de 56 piéds: </s> <s xml:id="echoid-s2383" xml:space="preserve">or ſi l’on fait toutes les opérations <lb/>qui ſont indiquées dans la derniere équation, l’on trouvera que l’é-<lb/>paiſſeur P S dupié-droit, c’eſt-à-dire y, doit être de 7 pieds 6 pouces, <lb/>pour être en équilibre avec la pouſſée de la Voûte.</s> <s xml:id="echoid-s2384" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2385" xml:space="preserve">15. </s> <s xml:id="echoid-s2386" xml:space="preserve">Je ſuis bien-aiſe de faire obſerver ici en paſſant, que toutes <lb/>les fois que nous avons multiplié l’expreſſion de la puiſſance O, <lb/>c’eſt-à-dire {nnb/a} par ſon bras de lévier PO ({af) - ac - ay/b}) les <lb/>lettres a & </s> <s xml:id="echoid-s2387" xml:space="preserve">b, ſe ſont évanouïes, n’étant reſté pour le produit que <lb/>fnn - cnn - ynn, qui n’eſt autre choſe que celui de f - c - y par <lb/>nn; </s> <s xml:id="echoid-s2388" xml:space="preserve">or comme f - c - y, eſt l’expreſſion de l’hipotenuſe NP du <lb/>triangle rectangle PON, & </s> <s xml:id="echoid-s2389" xml:space="preserve">nn la ſuperficie du vouſſoir CWGD, l’on <lb/>peut donc tirer cette conſéquence qui eſt que „toutes les fois que <lb/>„le triangle LKO ſera ſemblable au triangle PON, on n’aura qu’à <lb/>„multiplier l’expreſſion de la péſanteur abſoluë du vouſſoir par celle <pb o="19" file="0127" n="130" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> „de l’hipotenuſe NP; </s> <s xml:id="echoid-s2390" xml:space="preserve">pour avoir la pouſſée de la Voûte par raport <lb/>„au point d’apui P, ſans être obligé de faire aucune analogie; </s> <s xml:id="echoid-s2391" xml:space="preserve">c’eſt ce <lb/>que nous ſuivrons à l’avenir pour abreger les opérations; </s> <s xml:id="echoid-s2392" xml:space="preserve">mais „l’on <lb/>„fera attention que ceci n’a lieu que quand il eſt queſtion d’une <lb/>„Voûte en plein ceintre.</s> <s xml:id="echoid-s2393" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div164" type="section" level="2" n="15"> <head xml:id="echoid-head125" xml:space="preserve">Remarque quatriéme.</head> <p> <s xml:id="echoid-s2394" xml:space="preserve">16. </s> <s xml:id="echoid-s2395" xml:space="preserve">L’on remarquera encore, que (ſi l’on vouloit conſtruire un <lb/> <anchor type="note" xlink:label="note-0127-01a" xlink:href="note-0127-01"/> édifice où l’on ſeroit obligé de faire pluſieurs Voûtes les unes ſur <lb/>les autres ſoûtenuës par les mêmes piés-droits) il n’y auroit pas plus <lb/>de difficulté à trouver l’epaiſſeur de ſes piés-droits, que l’on n’en <lb/>a eu dans les cas précédens; </s> <s xml:id="echoid-s2396" xml:space="preserve">il arrivera ſeulement que les calculs <lb/>ſeront un peu plus compoſés, comme on en va juger.</s> <s xml:id="echoid-s2397" xml:space="preserve"/> </p> <div xml:id="echoid-div164" type="float" level="3" n="1"> <note position="right" xlink:label="note-0127-01" xlink:href="note-0127-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>3. <lb/><emph style="sc">Fig</emph>. 2.</note> </div> <p> <s xml:id="echoid-s2398" xml:space="preserve">Si l’on conſidere le profil repréſenté par la Figure 2. </s> <s xml:id="echoid-s2399" xml:space="preserve">l’on verra <lb/>qu’on y ſupoſe deux étages: </s> <s xml:id="echoid-s2400" xml:space="preserve">le premier, qui eſt couvert par deux <lb/>Voûtes de même grandeur, pourra être pris ſi l’on veut pour un <lb/>ſoûterain, au-deſſus duquel eſt un magaſin qui compoſe le ſecond <lb/>étage; </s> <s xml:id="echoid-s2401" xml:space="preserve">& </s> <s xml:id="echoid-s2402" xml:space="preserve">comme ce magaſin eſt couvert par une Voûte qui eſt ſoûte-<lb/>nuë par les mêmes piés-droits que celle du ſoûterrain, la pouſſée des <lb/>deux Voûtes répondra au même point d’apui P; </s> <s xml:id="echoid-s2403" xml:space="preserve">par conſéquent ſi <lb/>on diviſe les quarts de cercles BD & </s> <s xml:id="echoid-s2404" xml:space="preserve">WQ en deux également, & </s> <s xml:id="echoid-s2405" xml:space="preserve"><lb/>qu’on éleve aux points L & </s> <s xml:id="echoid-s2406" xml:space="preserve">X, les perpendiculaires LO & </s> <s xml:id="echoid-s2407" xml:space="preserve">XE, elles <lb/>répréſenteront comme à l’ordinaire la direction des puiſſances qui <lb/>ſoûtiendroient en équilibre la pouſſée des vouſſoirs LG & </s> <s xml:id="echoid-s2408" xml:space="preserve">XQ; </s> <s xml:id="echoid-s2409" xml:space="preserve">par <lb/>conſéquent, ſi du point d’apui P l’on abaiſſe ſur ces directions les <lb/>perpendiculaires PO & </s> <s xml:id="echoid-s2410" xml:space="preserve">PE, l’on aura d’une part le triangle LKA ſem-<lb/>blable à PON, & </s> <s xml:id="echoid-s2411" xml:space="preserve">de l’autre le triangle XIS ſemblable à PEH; </s> <s xml:id="echoid-s2412" xml:space="preserve">or <lb/>pour avoir la pouſſée des deux vouſſoirs LG & </s> <s xml:id="echoid-s2413" xml:space="preserve">XQ, on n’aura qu’à <lb/>multiplier la ſuperficie du premier LG par l’hipotenuſe NP du trian-<lb/>gle rectangle PON, & </s> <s xml:id="echoid-s2414" xml:space="preserve">celle du ſecond XQ par l’hipotenuſe PH <lb/>du triangle PEH, & </s> <s xml:id="echoid-s2415" xml:space="preserve">ajoûter ces deux produits enſemble; </s> <s xml:id="echoid-s2416" xml:space="preserve">ainſinom-<lb/>mant LV ou MZ, a; </s> <s xml:id="echoid-s2417" xml:space="preserve">BV, c; </s> <s xml:id="echoid-s2418" xml:space="preserve">ZP, d; </s> <s xml:id="echoid-s2419" xml:space="preserve">MP ſera a + d; </s> <s xml:id="echoid-s2420" xml:space="preserve">& </s> <s xml:id="echoid-s2421" xml:space="preserve">ZB étant <lb/>toûjours y, ML <anchor type="note" xlink:href="" symbol="*"/> ou MN ſera y + c; </s> <s xml:id="echoid-s2422" xml:space="preserve">par conſéquent NP ſera a + d <anchor type="note" xlink:label="note-0127-02a" xlink:href="note-0127-02"/> - c - y; </s> <s xml:id="echoid-s2423" xml:space="preserve">& </s> <s xml:id="echoid-s2424" xml:space="preserve">ſi l’on ſupoſe pour abreger a + d - c = f, NP ſera <lb/>f - y qui étant multiplié par nn ſuperficie du vouſſoir LG, l’on aura <lb/>nnf - nny pour le premier produit (c’eſt-à-dire) pour l’expreſſion <lb/>de la pouſſée de la Voûte ſuperieure, de même ſi on nomme Wr <lb/>b; </s> <s xml:id="echoid-s2425" xml:space="preserve">& </s> <s xml:id="echoid-s2426" xml:space="preserve">RP: </s> <s xml:id="echoid-s2427" xml:space="preserve">h; </s> <s xml:id="echoid-s2428" xml:space="preserve">RX ou RH ſera y + b, par conſéquent HP ſera h - b <lb/>- y, Et ſupoſant encore pour abreger h - b = p HP ſera p - y <lb/>qui étant multiplié par la ſuperficie du vouſſoir XQ que nous nom-<lb/>merons qq, l’on aura pqq - qqy pour le ſecond produit, ou ſi l’on <pb o="20" file="0128" n="131" rhead="LA SCIENCE DES INGENIEURS,"/> veut pour la pouſſée de la Voûte inferieure, qui étant ajoûtée avec <lb/>celle de la ſuperieure, il viendra nnf - nny + pqq - qqy pour la <lb/>pouſſée que ſoûtient le pié-droit P B: </s> <s xml:id="echoid-s2429" xml:space="preserve">& </s> <s xml:id="echoid-s2430" xml:space="preserve">comme la réſiſtance du <lb/>pié-droit jointe au vouſſoir ZLB, eſt exprimée comme ci-devant par <lb/>{ddy/2} - nny - nng (car nous faiſons abſtraction de la partie XW de <lb/>la Voûte du ſouterrain, parce que cette partie ſe trouve preſque en-<lb/>tierement enclavée dans le pié-droit) l’on aura donc cette équa-<lb/>tion nnf - nny + pqq - qqy = {dyy/2} + nny - nng; </s> <s xml:id="echoid-s2431" xml:space="preserve">d’où faiſant paſſer <lb/>dans le ſecond membre les termes où ſe trouvent l’inconnu, & </s> <s xml:id="echoid-s2432" xml:space="preserve">du <lb/>ſecond dans le premier ceux où l’inconnu ne ſe trouve point, l’on <lb/>aura nnf + {nng + pqq/d} = {yy/2} + {2nny + qqy/d} après avoir diviſé par <lb/>d; </s> <s xml:id="echoid-s2433" xml:space="preserve">& </s> <s xml:id="echoid-s2434" xml:space="preserve">ſi l’on ſupoſe {2nn + qq/d} = r, mettant r à la place de ſa valeur <lb/>multipliant toute l’équation par 2, & </s> <s xml:id="echoid-s2435" xml:space="preserve">faiſant du ſecond membre un <lb/>quarré parfait, l’on aura 2nng + 2nnf + 2pqq + rr = yy + 2ry + rr, <lb/>d’où dégageant l’inconnu il vient enfin 2nng + 2nnf + 2pqq + rr - r <lb/>= y, qui donne en terme connu la valeur de y; </s> <s xml:id="echoid-s2436" xml:space="preserve">ainſi l’on n’aura <lb/>qu’à déterminer ſi l’on veut les dimenſions de la figure pour avoir <lb/>la valeur des lettres, & </s> <s xml:id="echoid-s2437" xml:space="preserve">enſuite faire avec les nombres les mêmes <lb/>opérations que celles qui ſont indiquées dans l’équation, & </s> <s xml:id="echoid-s2438" xml:space="preserve">l’on <lb/>trouvera l’épaiſſeur qu’il faut donner aux piés-droits pour être en <lb/>équilibre avec la pouſſée des deux Voûtes.</s> <s xml:id="echoid-s2439" xml:space="preserve"/> </p> <div xml:id="echoid-div165" type="float" level="3" n="2"> <note symbol="*" position="right" xlink:label="note-0127-02" xlink:href="note-0127-02a" xml:space="preserve">Art. 15.</note> </div> <p> <s xml:id="echoid-s2440" xml:space="preserve">Quand les Voûtes ſont couvertes par une ſurface horiſontale <lb/>ſervant de rez-de-Chauſſée à l’étage qui eſt au-deſſus, il n’eſt pas <lb/>néceſſaire d’avoir égard aux poids des terres ou des autres maté-<lb/>riaux qu’on met au-deſſus des reins pour remplir les vuides; </s> <s xml:id="echoid-s2441" xml:space="preserve">car <lb/>comme ces matériaux agiſſent dans un ſens perpendiculaire, ils <lb/>font un effort qui diminuë en quelque façon la pouſſée puiſqu’ils <lb/>aident les piés-droits à y réſiſter: </s> <s xml:id="echoid-s2442" xml:space="preserve">ainſi il ſuffira de conſidérer la Voû-<lb/>te pour en avoir les piés-droits, comme s’il n’étoit pas queſtion de <lb/>cette nouvelle charge, c’eſt pourquoi je n’en ai pas fait mention <lb/>dans les calculs précédens.</s> <s xml:id="echoid-s2443" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div167" type="section" level="2" n="16"> <head xml:id="echoid-head126" style="it" xml:space="preserve">Remarque cinquiéme.</head> <p> <s xml:id="echoid-s2444" xml:space="preserve">Il ſe fait quelquefois des Voûtes dont l’impoſte ſaille au-delà du <lb/> <anchor type="note" xlink:label="note-0128-01a" xlink:href="note-0128-01"/> mur, & </s> <s xml:id="echoid-s2445" xml:space="preserve">alors cette Voûte eſt nommée encorbeillement, parce qu’elle <lb/>eſt portée par des corbeaux de Pierre: </s> <s xml:id="echoid-s2446" xml:space="preserve">telle eſt la Voûte en plain <pb o="21" file="0129" n="132" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> ceintre BDH, quirepoſe ſur les corbeaux BE & </s> <s xml:id="echoid-s2447" xml:space="preserve">HX, dont la ſaillie <lb/>EB & </s> <s xml:id="echoid-s2448" xml:space="preserve">HX eſt à peu-près égale à l’épaiſſeur de la Voûte: </s> <s xml:id="echoid-s2449" xml:space="preserve">comme <lb/>cette conſtruction n’eſt guére ſolide, je me garderai bien de la pro-<lb/>poſer pour modele, principalement dans les ouvrages de Fortifica-<lb/>tions, où il faut que les Voûtes ſoient d’une certaine épaiſſeur & </s> <s xml:id="echoid-s2450" xml:space="preserve">ſo-<lb/>lidement établis: </s> <s xml:id="echoid-s2451" xml:space="preserve">mon deſſein eſt ſeulement de montrer qu’elle <lb/>a beaucoup moins de pouſſée, que ſi elle repoſoit directement ſur <lb/>les piés-droits comme à l’ordinaire, & </s> <s xml:id="echoid-s2452" xml:space="preserve">qu’on peut la mettre en uſage <lb/>dans les bâtimens civils, quand on veut voûter quelqu’endroit dont <lb/>les murs qui doivent ſervir de piés-droits ſe trouvent tous faits, mais <lb/>trop foibles, parce qu’ils peuvent avoir été bâtis anciennement ſans <lb/>qu’on ait eu en vuë de leur faire porter une Voûte.</s> <s xml:id="echoid-s2453" xml:space="preserve"/> </p> <div xml:id="echoid-div167" type="float" level="3" n="1"> <note position="left" xlink:label="note-0128-01" xlink:href="note-0128-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>5. <lb/><emph style="sc">Fig</emph>. 1.</note> </div> <p> <s xml:id="echoid-s2454" xml:space="preserve">Or, pour juger de combien cet encorbeillement ſoulage les piés-<lb/>droits, nous tirerons les lignes comme à l’ordinaire, & </s> <s xml:id="echoid-s2455" xml:space="preserve">nous nom-<lb/>merons CV, c; </s> <s xml:id="echoid-s2456" xml:space="preserve">ZC ou PS, y; </s> <s xml:id="echoid-s2457" xml:space="preserve">ZP, d; </s> <s xml:id="echoid-s2458" xml:space="preserve">MP, f; </s> <s xml:id="echoid-s2459" xml:space="preserve">SR, g; </s> <s xml:id="echoid-s2460" xml:space="preserve">ainſi ML <lb/>ou MN ſera y + c; </s> <s xml:id="echoid-s2461" xml:space="preserve">& </s> <s xml:id="echoid-s2462" xml:space="preserve">par conſéquent NP ſera f - c - y, & </s> <s xml:id="echoid-s2463" xml:space="preserve">comme <lb/>nous ſupoſons, que la ſuperficie de chaque vouſſoir LGD ou LCB <lb/>eſt toûjours exprimée par nn il s’enſuit par l’article 15. </s> <s xml:id="echoid-s2464" xml:space="preserve">que multi-<lb/>pliant nn par NP (f - c - y) on aura fnn - cnn - nny, pour la <lb/>pouſſée de la Voûte; </s> <s xml:id="echoid-s2465" xml:space="preserve">d’un autre côté la réſiſtance des piés-droits <lb/>ſera toûjours {dyy/2}, à quoi ajoûtant celle du vouſſoir CLB <lb/>qui eſt le produit de nn par le bras de lévier P R (y + g) l’on au-<lb/>ra cette équation fnn - cnn - nny = {dyy/2} + ynn + gnn, ou bien <lb/>{2fnn - 2cnn - 2gnn/d} = yy + {4nny/d} après avoir fait la réduction, <lb/>multiplié par 2 & </s> <s xml:id="echoid-s2466" xml:space="preserve">diviſé par d, or ſi l’on change le ſecond mem-<lb/>bre en un quarré parfait & </s> <s xml:id="echoid-s2467" xml:space="preserve">qu’on dégage enſuite l’inconnu il viendra <lb/>{√2fnn - 2cnn - 2gnn\x{0020}/d} + {√4n<emph style="sub">4</emph>\x{0020}/dd} - {2nn/d} = y.</s> <s xml:id="echoid-s2468" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2469" xml:space="preserve">Pour connoître la valeur de l’inconnu, nous ſupoſerons que le <lb/>rayon AB eſt de 12 pieds, que la Voûte en a trois d’épaiſſeur, que <lb/>les piés-droits ont 15 pieds de hauteur, & </s> <s xml:id="echoid-s2470" xml:space="preserve">que la ligne SR (g) eſt <lb/>de 2 pieds, ainſi on trouvera que MP (f) vaut 24 pieds 10 pouces <lb/>& </s> <s xml:id="echoid-s2471" xml:space="preserve">que EV (c) vaut 5 pieds 2 pouces; </s> <s xml:id="echoid-s2472" xml:space="preserve">or puiſqu’on a la valeur de <lb/>toutes les lettres quiſe trouvent dans le premier membre de l’équa-<lb/>tion précédente, on trouvera en faiſant les opérations qui y ſont <lb/>indiquées, que l’épaiſſeur des piés-droits doit être de 5 pieds 5 pou-<lb/>ces; </s> <s xml:id="echoid-s2473" xml:space="preserve">& </s> <s xml:id="echoid-s2474" xml:space="preserve">comme nous avons vû dans l’art. </s> <s xml:id="echoid-s2475" xml:space="preserve">11. </s> <s xml:id="echoid-s2476" xml:space="preserve">que les piés-droits d’une <lb/>Voûte qui auroit les mêmes dimenſions que celle-ci ſans être ſou- <pb o="22" file="0130" n="133" rhead="LA SCIENCE DES INGENIEURS,"/> tenuë par des corbeaux, devoit avoir 6 pieds 6 pouces 7 lignes <lb/>d’épaiſſeur, il s’enſuit que l’encorbeillement donnera 1 pied 1 pou-<lb/>ce 7 lignes pour la différence de l’épaiſſeur des piés-droits.</s> <s xml:id="echoid-s2477" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2478" xml:space="preserve">On fera attention (quand on fait des Voûtes par encorbeillement) <lb/>de charger les piés-droits d’une bonne maçonnerie IR pour mainte-<lb/>nir ſolidement la queuë des pierres qui compoſent les corbeaux, <lb/>afin d’avoir un contre-poids qui faſſe équilibre à celui de la Voûte.</s> <s xml:id="echoid-s2479" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div169" type="section" level="2" n="17"> <head xml:id="echoid-head127" xml:space="preserve">PROPOSITION SECONDE.</head> <head xml:id="echoid-head128" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s2480" xml:space="preserve">Trouver quelle épaiſſeur il faut donner aux piés-droits d’u-<lb/>ne Voûte lorſque ces piés-droits auront un talud déterminé.</s> <s xml:id="echoid-s2481" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2482" xml:space="preserve">17. </s> <s xml:id="echoid-s2483" xml:space="preserve">Nous avons ſupoſé juſqu’ici que les piés-droits des Voûtes <lb/>étoient élevés à plomb des deux côtés, parce qu’il n’arrive guére <lb/>qu’on les faſſe autrement: </s> <s xml:id="echoid-s2484" xml:space="preserve">cependant, ſi on ſe rapelle ce qui a été <lb/>dit dans le premier Livre, l’on verra que leur donnant un peu de <lb/>talud du côté opoſé à la pouſſée, on pourra avec moins de Ma-<lb/>çonnerie les mettre en état de ſoutenir la pouſſée de la Voûte; </s> <s xml:id="echoid-s2485" xml:space="preserve">& </s> <s xml:id="echoid-s2486" xml:space="preserve"><lb/>c’eſt ce que l’on ſe propoſe d’expliquer ici, afin de ne rien négliger <lb/>de tout ce qui peut interreſſer le ſujet que je traite.</s> <s xml:id="echoid-s2487" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2488" xml:space="preserve">Pour trouver l’épaiſſeur ZB ou PS du pié-droit PB auquel on ſe <lb/>propoſe de donner un talud exprimé par FZ ou PX, je tire toutes <lb/>les lignes qu’on a tirées dans les Figures précédentes, & </s> <s xml:id="echoid-s2489" xml:space="preserve">je nomme <lb/>KA ou MF, a; </s> <s xml:id="echoid-s2490" xml:space="preserve">FZ ou PX, b; </s> <s xml:id="echoid-s2491" xml:space="preserve">BV, c; </s> <s xml:id="echoid-s2492" xml:space="preserve">ZX ou FP, d; </s> <s xml:id="echoid-s2493" xml:space="preserve">ZB, y; </s> <s xml:id="echoid-s2494" xml:space="preserve">ainſi FV <lb/> <anchor type="note" xlink:label="note-0130-01a" xlink:href="note-0130-01"/> ou ML ou MN ſera b + c + y; </s> <s xml:id="echoid-s2495" xml:space="preserve">& </s> <s xml:id="echoid-s2496" xml:space="preserve">MP a + d, par conſéquent NP <lb/>ſera a + d - b - c - y; </s> <s xml:id="echoid-s2497" xml:space="preserve">& </s> <s xml:id="echoid-s2498" xml:space="preserve">ſupoſant a + d - b - c = f, NP ſera <lb/>f - y; </s> <s xml:id="echoid-s2499" xml:space="preserve">or, comme les triangles LKA & </s> <s xml:id="echoid-s2500" xml:space="preserve">PON ſont ſemblables, mul-<lb/>tipliant f - y par nn; </s> <s xml:id="echoid-s2501" xml:space="preserve">c’eſt-à-dire par la ſuperficie du vouſſoir LGD, <lb/>on aura nnf - nny pour l’expreſſion de la pouſſée de la Voûte par <lb/>raport au point d’apui P.</s> <s xml:id="echoid-s2502" xml:space="preserve"/> </p> <div xml:id="echoid-div169" type="float" level="3" n="1"> <note position="left" xlink:label="note-0130-01" xlink:href="note-0130-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s2503" xml:space="preserve">Preſentement, pour avoir celle de la réſiſtance du pié-droit, je <lb/>conſidére que la ſuperficie du triangle rectangle PZX eſt {bd/2} & </s> <s xml:id="echoid-s2504" xml:space="preserve">que <lb/>ſi la ligne PR eſt les deux tiers de PX, le point R ſera celui où on <lb/>pourra réünir la ſuperficie du triangle; </s> <s xml:id="echoid-s2505" xml:space="preserve">ainſi multipliant {bd/a} par {2b/3}, <lb/>l’on aura après la réduction {bbd/3} pour le produit de la ſuperficie du <pb o="23" file="0131" n="134" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> triangle par le bras de lévier Pr, je multiplie de même la ſuperfi-<lb/>cie du rectangle XZBS (dy) par le bras delévier PT (b + {y/2}) pour <lb/>avoir bdy + {dyy/2}: </s> <s xml:id="echoid-s2506" xml:space="preserve">enfin comme le centre de gravité Q du vouſſoir <lb/>ELB répond au point R, je multiplie ſaſuperficie nn par le bras de lé-<lb/>vier PR; </s> <s xml:id="echoid-s2507" xml:space="preserve">c’eſt-à-dire par b + y - g (car je ſupoſe toûjours RS = g) & </s> <s xml:id="echoid-s2508" xml:space="preserve"><lb/>le produit donne bnn + ynn - gnn; </s> <s xml:id="echoid-s2509" xml:space="preserve">or ajoûtant enſemble ces trois <lb/>produits, l’on aura la réſiſtance du pié-droit, par conſéquent cette <lb/>équation fnn - nny = {bbd/3} + bdy + {dyy/2} + bnn + nny - gnn, ou <lb/>bien {fnn - bnn + gnn/d} + {bb/3} = {yy/2} + {2nny/d} + by, (après avoir diviſé <lb/>par d, & </s> <s xml:id="echoid-s2510" xml:space="preserve">fait paſſer dans les mêmes membres les termes où ſetrou-<lb/>vent l’inconnu.) </s> <s xml:id="echoid-s2511" xml:space="preserve">Or ſi l’on ſupoſe {2nn/d} + b = p, & </s> <s xml:id="echoid-s2512" xml:space="preserve">qu’on met-<lb/>te p à la place de ſa valeur, on pourra du ſecond membre en faire <lb/>un quarré parfait & </s> <s xml:id="echoid-s2513" xml:space="preserve">dégager l’inconnu comme à l’ordinaire pour avoir <lb/>cette derniere équation √{2fnn + 2gnn - 2bnn/d} - {2bb/3} + pp - p\x{0020} = y.</s> <s xml:id="echoid-s2514" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div171" type="section" level="2" n="18"> <head xml:id="echoid-head129" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s2515" xml:space="preserve">Supoſant la hauteur du pié-droit FP, (d) de 15 pieds, & </s> <s xml:id="echoid-s2516" xml:space="preserve">ſon <lb/>talud que EZ (b) de 3, KA (a) ſera de 9 pieds 10 pouces, BV (c) <lb/>de 2 pieds 2 pouces, ainſi a + d - b - c, c’eſt-à-dire f ſera de <lb/>19 pieds 8 pouces, & </s> <s xml:id="echoid-s2517" xml:space="preserve">la ſuperficie du vouſſoir LGD de 32 pieds; <lb/></s> <s xml:id="echoid-s2518" xml:space="preserve">or pour avoir la valeur de p qui eſt la ſeule lettre qui nous reſte à <lb/>connoître, je me rapelle qu’on a ſupoſé {2nnd/d} + b = p, & </s> <s xml:id="echoid-s2519" xml:space="preserve">comme <lb/>{2nn/d} vaut 4 pieds 3 pouces, & </s> <s xml:id="echoid-s2520" xml:space="preserve">b 3 pieds; </s> <s xml:id="echoid-s2521" xml:space="preserve">p vaudra donc 7 pieds <lb/>3 pouces; </s> <s xml:id="echoid-s2522" xml:space="preserve">ainſi ayant la valeur de toutes les lettres, je fais avec <lb/>les nombres les mêmes opérations quiſont indiquées dans l’équation <lb/>√{2fnn + 2gnn - 2bnn/d} - {2bb/3} + pp - p\x{0020} = y; </s> <s xml:id="echoid-s2523" xml:space="preserve">& </s> <s xml:id="echoid-s2524" xml:space="preserve">je trouve que y ou <lb/>ſi l’on veut l’épaiſſeur de ZB eſt de 3 pieds 9 pouces 3 lignes; </s> <s xml:id="echoid-s2525" xml:space="preserve">c’eſt-<lb/>à-dire que ſi l’on donne 3 pieds de talud au pié-droit & </s> <s xml:id="echoid-s2526" xml:space="preserve">3 pieds 9 <lb/>pouces 3 lignes d’épaiſſeur au ſommet, ils ſeront en équibre par <lb/>leur réſiſtance avec la pouſſée de la Voûte.</s> <s xml:id="echoid-s2527" xml:space="preserve"/> </p> <pb o="24" file="0132" n="135" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div172" type="section" level="2" n="19"> <head xml:id="echoid-head130" style="it" xml:space="preserve">Remarque prémiere.</head> <p> <s xml:id="echoid-s2528" xml:space="preserve">18. </s> <s xml:id="echoid-s2529" xml:space="preserve">Pour juger combien il faudroit moins de Maçonnerie pour <lb/>les piés-droits de la Voûte que nous venons de calculer, que pour <lb/>ceux du premier Problême, il n’y a qu’à comparer l’épaiſſeur du <lb/>Profil de l’un, avec celle du Profil de l’autre, puiſqu’ils ontla même <lb/>hauteur: </s> <s xml:id="echoid-s2530" xml:space="preserve">pour cela j’ajoûte les lignes ZB & </s> <s xml:id="echoid-s2531" xml:space="preserve">PS enſemble; </s> <s xml:id="echoid-s2532" xml:space="preserve">c’eſt-à-<lb/>dire 3 pieds 9 pouces 3 lignes, & </s> <s xml:id="echoid-s2533" xml:space="preserve">6 pieds 9 pouces 3 lignes, & </s> <s xml:id="echoid-s2534" xml:space="preserve"><lb/>prens la moitié de la ſomme qui eſt de 5 pieds 3 pouces 3 lignes <lb/>pour l’épaiſſeur réduite, qui étant comparée avec 6 pieds 6 pouces <lb/>7 lignes, épaiſſeur des piés-droits du premier Probléme, la diffé-<lb/>rence ſera d’un pied trois pouces 4 lignes: </s> <s xml:id="echoid-s2535" xml:space="preserve">ce qui fait voir qu’en don-<lb/>nant au pié-droit un talud tel que nous l’avons ſupoſé, on employera <lb/>environ un cinquiéme moins de Maçonnerie, que ſi l’on avoit fait <lb/>ces pié-droits à plomb des deux côtés.</s> <s xml:id="echoid-s2536" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div173" type="section" level="2" n="20"> <head xml:id="echoid-head131" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s2537" xml:space="preserve">19. </s> <s xml:id="echoid-s2538" xml:space="preserve">Quand on a trouvé, comme dans le premier Probléme, l’é-<lb/>paiſſeur qu’il faut donner aux piés-droits d’une Voûte, pour être en <lb/>équilibre avec la pouſſée, on peut ſans augmenter la depenſe mettre <lb/>la réſiſtance des piés-droits beaucoup au-deſſus de la pouſſée afin d’ê-<lb/>tre ſûr que quelque choſe qui arrive les piés-droits demeurerontiné-<lb/>branlables: </s> <s xml:id="echoid-s2539" xml:space="preserve">pour cela il ne faut que diminuer un peu l’épaiſſeur des <lb/>piés-droits au ſommet, & </s> <s xml:id="echoid-s2540" xml:space="preserve">augmenter celle de la baſe de la même quan-<lb/>tité; </s> <s xml:id="echoid-s2541" xml:space="preserve">par exemple, ſi l’on a trouvé qu’il falloit 7 pieds d’épaiſſeur aux <lb/>piés-droits, on en donnera 6 au ſommet & </s> <s xml:id="echoid-s2542" xml:space="preserve">8 à la baſe.</s> <s xml:id="echoid-s2543" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2544" xml:space="preserve">Les murs, qui ſont expoſés à l’injure de l’air, & </s> <s xml:id="echoid-s2545" xml:space="preserve">qui ont un talud, <lb/>étant plus ſujets à être dégradés que ceux qui n’en ont point, on <lb/>ne manquera pas de dire que dans la pratique on fera peu d’atten-<lb/>tion à l’avantage que je prétend en tirer: </s> <s xml:id="echoid-s2546" xml:space="preserve">l’on prendra là-deſſus le <lb/>parti qu’on jugera à propos, ce que l’on vient d’enſeigner n’en ſera <lb/>pas moins vrai.</s> <s xml:id="echoid-s2547" xml:space="preserve"/> </p> <pb o="25" file="0133" n="136" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div174" type="section" level="2" n="21"> <head xml:id="echoid-head132" xml:space="preserve">PROPOSITION TROISIE’ME.</head> <head xml:id="echoid-head133" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s2548" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux piés-droits des <lb/>Voûtes lorſque ces piés-droits ſont accompagnés de contreforts.</s> <s xml:id="echoid-s2549" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2550" xml:space="preserve">Je ſupoſe qu’il eſt queſtion de conſtruire une Voûte dont les piés-<lb/>droits doivent être ſoûtenus par des contreforts; </s> <s xml:id="echoid-s2551" xml:space="preserve">que l’on eſt con-<lb/>venu de la longueur & </s> <s xml:id="echoid-s2552" xml:space="preserve">de l’épaiſſeur de ces contreforts, auſſi-bien <lb/>que de la diſtance des uns aux autres; </s> <s xml:id="echoid-s2553" xml:space="preserve">& </s> <s xml:id="echoid-s2554" xml:space="preserve">qu’il n’eſt plus queſtion que <lb/>de ſavoir l’épaiſſeur qu’il faudra donner aux piés-droits, afin qu’é-<lb/>tant aidés des contreforts, le tout ſoit en équilibre avec la pouſſée.</s> <s xml:id="echoid-s2555" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2556" xml:space="preserve">Si l’on conſidére la Figure cinquiéme, l’on verra que le point <lb/>d’apui qui ſoûtient tous les efforts de la pouſſée de la Voûte n’eſt plus <lb/>comme ci-devant à l’endroit r de la baſe des piés-droits, mais bien <lb/>à l’extrêmité P de la queuë des contreforts rPQC; </s> <s xml:id="echoid-s2557" xml:space="preserve">ce qui montre <lb/>que la perpendiculaire PO, abaiſſée ſur la direction LO de la puiſ-<lb/>ſance, exprime le bras de lévier qui répond à cette puiſſance: <lb/></s> <s xml:id="echoid-s2558" xml:space="preserve">cela poſé, ayant tiré les autres lignes comme à l’ordinaire, nous <lb/>nommerons KA ou MZ, a; </s> <s xml:id="echoid-s2559" xml:space="preserve">ZC ou Pr, b; </s> <s xml:id="echoid-s2560" xml:space="preserve">BV, c; </s> <s xml:id="echoid-s2561" xml:space="preserve">Cr, d; </s> <s xml:id="echoid-s2562" xml:space="preserve">CB ou <lb/> <anchor type="note" xlink:label="note-0133-01a" xlink:href="note-0133-01"/> rS, y; </s> <s xml:id="echoid-s2563" xml:space="preserve">ainſi ML ou MN, ſera b + c + y; </s> <s xml:id="echoid-s2564" xml:space="preserve">& </s> <s xml:id="echoid-s2565" xml:space="preserve">MP, a + d; </s> <s xml:id="echoid-s2566" xml:space="preserve">par conſé-<lb/>quent NP, a + d - b - c - y, ou bien f - y en ſupoſant a + d <lb/>- b - c = f.</s> <s xml:id="echoid-s2567" xml:space="preserve"/> </p> <div xml:id="echoid-div174" type="float" level="3" n="1"> <note position="right" xlink:label="note-0133-01" xlink:href="note-0133-01a" xml:space="preserve"><emph style="sc">Fig</emph> 4. <lb/>& 5.</note> </div> <p> <s xml:id="echoid-s2568" xml:space="preserve">Comme le triangle PON eſt ſemblable à LKA, il s’enſuit que mul-<lb/>tipliant la ſuperficie du vouſſoir LGD (nn) par NP (f - y) on <lb/>aura fnn - ynn pour l’expreſſion de la pouſſée de la Voûte: </s> <s xml:id="echoid-s2569" xml:space="preserve"><anchor type="note" xlink:href="" symbol="*"/> pre- <anchor type="note" xlink:label="note-0133-02a" xlink:href="note-0133-02"/> ſentement pour avoir celle de réſiſtance des piés-droits & </s> <s xml:id="echoid-s2570" xml:space="preserve">des con-<lb/>treforts, je conſidére que les contreforts, tels que ceux dont on ſe <lb/>ſert pour ſoûtenir les Voûtes, ont toûjours leur ſommet QC, termi-<lb/>né en pante, pour faciliter l’écoulement des eaux de pluye; </s> <s xml:id="echoid-s2571" xml:space="preserve">c’eſt <lb/>pourquoi j’abaiſſe la perpendiculaire QH ſur Cr, & </s> <s xml:id="echoid-s2572" xml:space="preserve">diviſe CH en <lb/>deux également au point I, afin d’avoir la ligne Ir, que nous nom-<lb/>merons h; </s> <s xml:id="echoid-s2573" xml:space="preserve">qui étant multiplié par Pr (b), l’on aura bd pour la ſu-<lb/>perficie de la coupe du contrefort PQCr, que nous ſupoſerons réü-<lb/>ni au point T milieu de Pr (comme ſi cette coupe étoit un rec-<lb/>tangle) afin d’éviter les petits détails auſquels on ſeroit aſſujeti, ſi <lb/>l’on vouloit examiner les choſes dans toute leur préciſion; </s> <s xml:id="echoid-s2574" xml:space="preserve">ainſi <lb/>multipliant bh par PT({b/2}) on aura {bbb/2} pour le produit du poids 4 <lb/>par ſon bras de lévier.</s> <s xml:id="echoid-s2575" xml:space="preserve"/> </p> <div xml:id="echoid-div175" type="float" level="3" n="2"> <note symbol="*" position="right" xlink:label="note-0133-02" xlink:href="note-0133-02a" xml:space="preserve">Art. 15.</note> </div> <pb o="26" file="0134" n="137" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s2576" xml:space="preserve">Car nous ſupoſons que la baſe des contreforts eſt rectangulaire; <lb/></s> <s xml:id="echoid-s2577" xml:space="preserve">mais comme il faut avoir égard au raport de l’épaiſſeur des contre-<lb/>forts à leur diſtance, nous ſupoſerons que ce raport eſt comme 1 à <lb/>2; </s> <s xml:id="echoid-s2578" xml:space="preserve">c’eſt-à-dire par exemple, que ſi les contreforts ont trois pieds <lb/>d’épaiſſeur, ils ſeront à 6 de diſtance; </s> <s xml:id="echoid-s2579" xml:space="preserve">ainſi comme ils occupent un <lb/>tiers de l’eſpace qui regne derriere les piés-droits, il faudra donc <lb/>diviſer {bbb/2} par trois, afin d’avoir {bbb/6} pour la réſiſtance des con-<lb/>treforts, comme on l’a expliqué dans l’article 46 du premier Livre.</s> <s xml:id="echoid-s2580" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2581" xml:space="preserve">Delà je paſſe aux piés-droits rB, dont la ſuperficie, ou ſi l’on veut <lb/>le poids 5, eſt dy, qui étant multiplié par ſon bras de lévier PX <lb/>(b + {y/2}) l’on aura bdy + {dyy/2};</s> <s xml:id="echoid-s2582" xml:space="preserve">; enfin je multiplie la ſuperficie du <lb/>vouſſoir CFB (nn), c’eſt-à-dire, le poids 6, par ſon bras de lévier PR <lb/>(b + y - g) & </s> <s xml:id="echoid-s2583" xml:space="preserve">le produit donne nnb + nny - nng, qui étant ajoûté <lb/>avecles deux précédens, on aura l’expreſſion de la puiſſance réſiſtan-<lb/>te, qui étant comparée avec celle qui agit, donne cette équation dans <lb/>l’état d’équilibre: </s> <s xml:id="echoid-s2584" xml:space="preserve">nnf - nny = {bbb/6} + bdy + {dyy/2} + nnb + nny - nng, <lb/>laquelle étant réduite, il vient {nnf + nng - nnb/d} - {bbb/6d} = {yy/2} + {2nny/d} <lb/>+ by; </s> <s xml:id="echoid-s2585" xml:space="preserve">& </s> <s xml:id="echoid-s2586" xml:space="preserve">ſupoſant {2nn/d} + b = p; </s> <s xml:id="echoid-s2587" xml:space="preserve">on mettra p à la place de ſa <lb/>valeur pour changer le ſecond membre en un quarré parfait, <lb/>& </s> <s xml:id="echoid-s2588" xml:space="preserve">dégager l’inconnu, afin d’avoir cette derniere équation <lb/>√{2nnf + 2nng - 2nnh/d} - {bbb/3d} + pp - p\x{0020} = y, qui donne ce que l’on <lb/>demande.</s> <s xml:id="echoid-s2589" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div177" type="section" level="2" n="22"> <head xml:id="echoid-head134" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s2590" xml:space="preserve">Supoſant le rayon AB de 12 pieds; </s> <s xml:id="echoid-s2591" xml:space="preserve">AF de 15; </s> <s xml:id="echoid-s2592" xml:space="preserve">KA (a) ſera toû-<lb/>jours de 9 pieds 10 pouces, BV (c) de 2 pieds 2 pouces, & </s> <s xml:id="echoid-s2593" xml:space="preserve">le <lb/>vouſſoir LGD (nn) de 56 pieds quarrés; </s> <s xml:id="echoid-s2594" xml:space="preserve">d’un autre côté nous ſu-<lb/>poſerons que la longueur Pr (b) des contreforts eſt de 5 pieds; <lb/></s> <s xml:id="echoid-s2595" xml:space="preserve">que la hauteur ZP (d) des piés-droits eſt encore de 15 pieds; </s> <s xml:id="echoid-s2596" xml:space="preserve">& </s> <s xml:id="echoid-s2597" xml:space="preserve"><lb/>que CH eſt égal à HQ: </s> <s xml:id="echoid-s2598" xml:space="preserve">par conſéquent Ir ſera de 12 pieds 6 pou-<lb/>ces. </s> <s xml:id="echoid-s2599" xml:space="preserve">On trouvera auſſi que f eſt de 17 pieds 8 pouces, & </s> <s xml:id="echoid-s2600" xml:space="preserve">p de 12 <lb/>pieds 6 pouces: </s> <s xml:id="echoid-s2601" xml:space="preserve">cela poſé, ſi l’on fait avec la valeur des let-<lb/>tres les opérations qui ſont marquées dans l’équation <lb/>√{2nnf - 2nng - 2nnb/d} - {bbb/3d} + pp - p\x{0020} = y, l’on trouvera que <lb/>l’épaiſſeur rS des piés-droits doit être de 3 pieds 1 pouce 5 lignes, <pb o="27" file="0135" n="138" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> pour qu’aidés des contreforts ils ſoient en équilibre avec la pouſſée <lb/>de la Voûte.</s> <s xml:id="echoid-s2602" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div178" type="section" level="2" n="23"> <head xml:id="echoid-head135" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s2603" xml:space="preserve">21. </s> <s xml:id="echoid-s2604" xml:space="preserve">Pour connoître l’épargne qu’on peut faire ſur la Maçonnerie, <lb/>quand on employe des contreforts, il faut ſe reſſouvenir que dans <lb/>l’Article 13. </s> <s xml:id="echoid-s2605" xml:space="preserve">nous avons trouvé qu’il falloit donner 7 pieds 8 pou-<lb/>ces 6 lignes d’épaiſſeur aux piés-droits d’une Voûte ſemblable à celle-<lb/>ci pour être en équilibre avec la pouſſée; </s> <s xml:id="echoid-s2606" xml:space="preserve">ainſi cette dimenſion étant <lb/>multipliée par la hauteur 15 des piés-droits, le produit ſera 115 <lb/>pieds 7 pouces 6 lignes pour l’eſtimation des mêmes piés-droits: <lb/></s> <s xml:id="echoid-s2607" xml:space="preserve">preſentement ſi on multiplie auſſi l’épaiſſeur que nous venons de <lb/>trouver; </s> <s xml:id="echoid-s2608" xml:space="preserve">c’eſt-à-dire, 3 pieds 1 pouce 5 lignes, par 15, l’on trouvera <lb/>environ 47 pieds 6 pouces pour l’eſtimation des piés-droits rB; </s> <s xml:id="echoid-s2609" xml:space="preserve"><lb/>mais comme il faut auſſi faire celle des contreforts, je multiplie leur <lb/>hauteur réduite Ir, qui eſt 12 pieds 6 pouces, par la longueur Pr, de <lb/>5 pieds, & </s> <s xml:id="echoid-s2610" xml:space="preserve">je prens le tiers du produit à cauſe que les contreforts <lb/>n’occupent qu’un tiers de l’eſpace qui regne derriere les piés-droits, <lb/>& </s> <s xml:id="echoid-s2611" xml:space="preserve">il vient 20 pieds 10 pouces, que j’ajoûte avec 47 pieds 6 pou-<lb/>ces, pour avoir 68 pieds 4 pouces, qui étant comparés avec 115 <lb/>pieds 7 pouces 6 lignes, la différence eſt 47 pieds 3 pouces 6 lignes: </s> <s xml:id="echoid-s2612" xml:space="preserve"><lb/>ce qui fait voir qu’on employera environ deux cinquiémes moins de <lb/>Maçonnerie, en ajoûtant des contreforts tels que nous venons de <lb/>les ſupoſer, qu’il n’en auroit fallu en n’en faiſant point: </s> <s xml:id="echoid-s2613" xml:space="preserve">par conſé-<lb/>quent, ſi au lieu de donner 5 pieds de longueur aux contreforts, on <lb/>leur en donnoit 5 pieds & </s> <s xml:id="echoid-s2614" xml:space="preserve">demi, la réſiſtance des piés-droits ſeroit <lb/>beaucoup au-deſſus de la pouſſée de la Voûte, & </s> <s xml:id="echoid-s2615" xml:space="preserve">on épargneroit en-<lb/>core bien de la Maçonnerie; </s> <s xml:id="echoid-s2616" xml:space="preserve">ou ſi l’on veut on pourroit laiſſer les <lb/>contreforts comme ils ſont, & </s> <s xml:id="echoid-s2617" xml:space="preserve">donner 3 pieds & </s> <s xml:id="echoid-s2618" xml:space="preserve">demi dépaiſſeur aux <lb/>piés-droits: </s> <s xml:id="echoid-s2619" xml:space="preserve">ce qui reviendra à peu-près au même.</s> <s xml:id="echoid-s2620" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div179" type="section" level="2" n="24"> <head xml:id="echoid-head136" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s2621" xml:space="preserve">22. </s> <s xml:id="echoid-s2622" xml:space="preserve">On obſervera en paſſant qu’en reglant la diſtance des con-<lb/>treforts, on ne doit pas troples éloigner nileur donner trop de lon-<lb/>gueur, crainte d’affoiblir l’épaiſſeur des piés-droits, ſi l’on vouloit <lb/>conſidérer le tout dans l’état d’équilibre; </s> <s xml:id="echoid-s2623" xml:space="preserve">puiſqu’il faut avoir égard <lb/>à la liaiſon des matériaux qui ne doivent point dans la pratique être <lb/>regardés comme abſolument indiſſolubles: </s> <s xml:id="echoid-s2624" xml:space="preserve">je veux dire (par exem-<lb/>ple) que ſi l’on s’apercevoit que pour avoir donné trop de longueur <lb/>aux contreforts, la valeur de y ne fût point ſuffiſante pour rendre <pb o="28" file="0136" n="139" rhead="LA SCIENCE DES INGENIEURS,"/> les piés-droits d’une épaiſſeur raiſonnable, deſorte qu’on pourroit <lb/>craindre que la pouſſée de la Voûte fit ſouffler la Maçonnerie entre-<lb/>deux contreforts, il vaudroit mieux diminuer la longueur des con-<lb/>treforts afin que les piés-droits en devinſſent plus épais; </s> <s xml:id="echoid-s2625" xml:space="preserve">par la même <lb/>raiſon il eſt plus à propos de partager la Maçonnerie qu’on deſtine <lb/>à ſoûtenir les piés-droits en multipliant les contreforts, que d’en met-<lb/>tre une moindre quantité, & </s> <s xml:id="echoid-s2626" xml:space="preserve">les faire plus épais; </s> <s xml:id="echoid-s2627" xml:space="preserve">je veux dire par <lb/>exemple que ſi l’on vouloit ſoûtenir une Voûte par des contreforts, <lb/>dont la Maçonnerie occupât un tiers de l’eſpace qui regne entreles <lb/>piés-droits & </s> <s xml:id="echoid-s2628" xml:space="preserve">la queuë des contreforts, au lieu de faire les contreforts <lb/>de 6 pieds d’épaiſſeur & </s> <s xml:id="echoid-s2629" xml:space="preserve">de 12 pieds de diſtance de l’un à l’autre, <lb/>il vaudroit beaucoup mieux ne leur donner que 3 pieds d’épaiſſeur, <lb/>& </s> <s xml:id="echoid-s2630" xml:space="preserve">les mettre à ſix pieds de diſtance; </s> <s xml:id="echoid-s2631" xml:space="preserve">parce que plus les piés-droits <lb/>auront de points d’apui, & </s> <s xml:id="echoid-s2632" xml:space="preserve">plus l’ouvrage ſera ſolide: </s> <s xml:id="echoid-s2633" xml:space="preserve">l’on ſent bien <lb/>que je veux parler des contreforts qui ſont apliqués aux ouvrages <lb/>de Fortiſications; </s> <s xml:id="echoid-s2634" xml:space="preserve">car je n’ignore pas que quand il s’agit de quel-<lb/>qu’autre édifice, où il faut que la décoration & </s> <s xml:id="echoid-s2635" xml:space="preserve">la ſolidité ſoient de <lb/>concert (comme par exemple aux Egliſes) il n’eſt pas toûjours libre <lb/>de déterminer la diſtance des contreforts, puiſqu’il faut avoir égard <lb/>à la largeur des croiſées qui ſont pratiquées entre-deux, & </s> <s xml:id="echoid-s2636" xml:space="preserve">aux en-<lb/>droits de la Voûte qui doivent être arboutés préférablement à d’au-<lb/>tres, parce que dans ces ſortes d’édifices les Voûtes n’agiſſent point <lb/>par-tout également, leur pouſſée ſe réüniſſant à certains points, qui <lb/>indiquent d’eux-même la poſition des contreforts.</s> <s xml:id="echoid-s2637" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div180" type="section" level="2" n="25"> <head xml:id="echoid-head137" style="it" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s2638" xml:space="preserve">23. </s> <s xml:id="echoid-s2639" xml:space="preserve">On peut encore remarquer, que la pouſſée d’une Voûte <lb/>augmente ou diminuë ſelon que le point d’apui P, eſt éloigné du <lb/>point S, extrêmité de la perpendiculaire BS; </s> <s xml:id="echoid-s2640" xml:space="preserve">car ſil’on ſe rapelle que <lb/>cette pouſſée dépend du produit de la péſanteur rélative du vouſ-<lb/>ſoir LGD par la perpendiculaire PO, l’on verra que plus le point <lb/>d’apui P ſera éloigné de S, plus la perpendiculaire PO ſera racour-<lb/>cie; </s> <s xml:id="echoid-s2641" xml:space="preserve">ainſi plus la baſe des piés-droits aura de largeur & </s> <s xml:id="echoid-s2642" xml:space="preserve">moins il fau-<lb/>dra de réſiſtance pour ſoûtenir la pouſſée: </s> <s xml:id="echoid-s2643" xml:space="preserve">que s’il arrivoit que le <lb/>point d’apui P fut tellement éloigné de S que la ligne de direction <lb/>LO paſſat pour le point P, c’eſt-à-dire, que les points O & </s> <s xml:id="echoid-s2644" xml:space="preserve">P fuſ-<lb/>ſent confondus, alors l’action du vouſſoir LGD ne feroit aucun <lb/>effet ſur le pié-droit: </s> <s xml:id="echoid-s2645" xml:space="preserve">car la ligne MP deviendroit zéro, & </s> <s xml:id="echoid-s2646" xml:space="preserve">zéro <lb/>multiplié par nn, ne peut donner que zéro.</s> <s xml:id="echoid-s2647" xml:space="preserve"/> </p> <pb o="29" file="0137" n="140" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div181" type="section" level="2" n="26"> <head xml:id="echoid-head138" style="it" xml:space="preserve">Remarque quatrième.</head> <p> <s xml:id="echoid-s2648" xml:space="preserve">24. </s> <s xml:id="echoid-s2649" xml:space="preserve">Puiſque tous les points d’apui qui ſoûtiennent la pouſſée d’une <lb/>Voûte ſe rencontrent poſitivement ſous la queuë des contreforts, <lb/>on voit qu’en conſtruiſant les fondemens on ne ſauroit les faire trop <lb/>ſolides en ces endroits-là; </s> <s xml:id="echoid-s2650" xml:space="preserve">c’eſt pourquoi je voudrois qu’ils fuſſent <lb/>compoſés des plus gros quartiers de pierres poſées ſur deux rangs <lb/>de madriers, quand même le terrain ſur lequel ou voudroit aſſeoir <lb/>la Fondation paroîtroit ferme; </s> <s xml:id="echoid-s2651" xml:space="preserve">puiſqu’il n’y a point à douter que la <lb/>Voûte, ſi elle eſt maſſive, ne cauſe par ſa pouſſée quelque af-<lb/>faiſſement à l’extrêmité des contreforts: </s> <s xml:id="echoid-s2652" xml:space="preserve">il paroît même que pour <lb/>plus de ſûreté on ne feroit pas mal de faire les fondemens des con-<lb/>treforts d’un pied & </s> <s xml:id="echoid-s2653" xml:space="preserve">demi ou deux pieds plus longs que les contre-<lb/>forts mêmes, donnant auſſi beaucoup de retraite ſur les côtés, afin <lb/>d’avoir de grands ampâtemens, qui allongent le bras de lévier & </s> <s xml:id="echoid-s2654" xml:space="preserve"><lb/>fortifient le point d’apui. </s> <s xml:id="echoid-s2655" xml:space="preserve">J’ai vû un Magaſin à poudre dont la Voûte <lb/>s’eſt fenduë des deux côtés au milieu des reins depuis un pignon <lb/>juſqu’à l’autre, peu de tems après avoir été bâti, quoique les dimen-<lb/>ſions des piés-droits & </s> <s xml:id="echoid-s2656" xml:space="preserve">des contreforts fuſſent beaucoup au-deſſus <lb/>de celles qu’il auroit falu pour en ſoutenir la pouſſée, & </s> <s xml:id="echoid-s2657" xml:space="preserve">que la Ma-<lb/>çonnerie fut fort bonne; </s> <s xml:id="echoid-s2658" xml:space="preserve">ayant examiné de quelle part cela pouvoit <lb/>provenir, je me ſuis aperçû que le terrain au-deſſus des fondemens <lb/>de la queuë des contreforts avoit flêchi, au lieu que cela ne ſeroit <lb/>pas arrivé ſi l’on avoit mis deux ou trois bons madriers l’un ſur l’au-<lb/>tre pour aſſurer le point d’apui.</s> <s xml:id="echoid-s2659" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2660" xml:space="preserve">Les Ingenieurs qui ont beaucoup d’experience ſentiront mieux <lb/>que perſonne la conſéquence de cette remarque, non-ſeulement au <lb/>ſujet des contreforts; </s> <s xml:id="echoid-s2661" xml:space="preserve">mais encore pour tous les autres fondemens <lb/>qui doivent ſervir de point d’apui: </s> <s xml:id="echoid-s2662" xml:space="preserve">auſſi voit-on que M. </s> <s xml:id="echoid-s2663" xml:space="preserve">de Vauban <lb/>en fortifiant le neuf Briſack a aſſuré le bord des fondemens de tous <lb/>les revêtemens de Maçonnerie par un rang de madriers qui regne le <lb/>long du pourtour de chaque ouvrage.</s> <s xml:id="echoid-s2664" xml:space="preserve"/> </p> <pb o="30" file="0138" n="141" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div182" type="section" level="2" n="27"> <head xml:id="echoid-head139" xml:space="preserve">CHAPITRE TROISIE’ME.</head> <head xml:id="echoid-head140" style="it" xml:space="preserve">Dela maniere detrouver l’épaiſſeur des pié-droits des Voûtes <lb/>ſurbaiſſées en tiers-points, en plate-Bande, & celles des cu-<lb/>lées des Ponts de Maçonnerie.</head> <p> <s xml:id="echoid-s2665" xml:space="preserve">JE crois avoir ſuffiſamment expliqué les Voûtes en plein ceintre <lb/>dans le Chapitre précédent pour n’en plus faire mention; </s> <s xml:id="echoid-s2666" xml:space="preserve">c’eſt <lb/>pourquoi je vais examiner dans celui-ci celles que l’on nomme <lb/>ſurbaiſſées ou Elliptiques, les autres qu’on apelle Gothiques, ou en <lb/>tiers-points, enfin celles que l’on nomme plate-bande, parce qu’elles <lb/>ne font aucune courbure ſenſible, étant plates comme un plat-fond. <lb/></s> <s xml:id="echoid-s2667" xml:space="preserve">Cependant, comme les Voûtes ſurbaiſſées dont nous allons parler ſe-<lb/>ront ſupoſées parfaitement Elliptiques, & </s> <s xml:id="echoid-s2668" xml:space="preserve">non point tracées par des <lb/>portions de cercle comme font la plûpart des Ouvriers, il eſt bon <lb/>avant toutes choſes de prévenir le lecteur de quelque propriété des <lb/>Sections Coniques, auſquelles nous ſerons obligé d’avoir recours, <lb/>afin de ne rien ſupoſer dont on n’aperçoive ſur le champ les raiſons; </s> <s xml:id="echoid-s2669" xml:space="preserve"><lb/>ainſi on fera bien de s’apliquer à ce qui ſuit.</s> <s xml:id="echoid-s2670" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div183" type="section" level="2" n="28"> <head xml:id="echoid-head141" style="it" xml:space="preserve">Principes tirés des Sections Coniques.</head> <p> <s xml:id="echoid-s2671" xml:space="preserve">25. </s> <s xml:id="echoid-s2672" xml:space="preserve">Il eſt démontré dans les Sections Coniques, que ſi l’on méne <lb/> <anchor type="note" xlink:label="note-0138-01a" xlink:href="note-0138-01"/> une ordonnée GH au grand axe AB d’une Ellipſe, le rectangle com-<lb/>pris ſous AG & </s> <s xml:id="echoid-s2673" xml:space="preserve">GB eſt au quarré de GH, comme le quarré de AF <lb/>eſt au quarré de FD: </s> <s xml:id="echoid-s2674" xml:space="preserve">ainſi nommant AF, a; </s> <s xml:id="echoid-s2675" xml:space="preserve">FD, b; </s> <s xml:id="echoid-s2676" xml:space="preserve">GF, x; </s> <s xml:id="echoid-s2677" xml:space="preserve">GH, y; <lb/></s> <s xml:id="echoid-s2678" xml:space="preserve">on aura aa - xx. </s> <s xml:id="echoid-s2679" xml:space="preserve">yy : </s> <s xml:id="echoid-s2680" xml:space="preserve">: </s> <s xml:id="echoid-s2681" xml:space="preserve">aa. </s> <s xml:id="echoid-s2682" xml:space="preserve">bb.</s> <s xml:id="echoid-s2683" xml:space="preserve"/> </p> <div xml:id="echoid-div183" type="float" level="3" n="1"> <note position="left" xlink:label="note-0138-01" xlink:href="note-0138-01a" xml:space="preserve"><emph style="sc">Plan</emph>. 5. <lb/><emph style="sc">Fig</emph>. 7.</note> </div> </div> <div xml:id="echoid-div185" type="section" level="2" n="29"> <head xml:id="echoid-head142" style="it" xml:space="preserve">Second Principe.</head> <p> <s xml:id="echoid-s2684" xml:space="preserve">26. </s> <s xml:id="echoid-s2685" xml:space="preserve">Il eſt auſſi démontré, que ſi l’on fait FI troiſiéme proportion-<lb/> <anchor type="note" xlink:label="note-0138-02a" xlink:href="note-0138-02"/> nelle à FG & </s> <s xml:id="echoid-s2686" xml:space="preserve">à FA, tirant la ligne HI, elle ſera tengente au point <lb/>H, ce qui donne FI={aa/x}, d’où l’on tire IG={aa-xx/x}.</s> <s xml:id="echoid-s2687" xml:space="preserve"/> </p> <div xml:id="echoid-div185" type="float" level="3" n="1"> <note position="left" xlink:label="note-0138-02" xlink:href="note-0138-02a" xml:space="preserve">V. le C. <lb/>Art. 436.</note> </div> <pb o="31" file="0139" n="142" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div187" type="section" level="2" n="30"> <head xml:id="echoid-head143" style="it" xml:space="preserve">Troiſiéme Principe.</head> <p> <s xml:id="echoid-s2688" xml:space="preserve">27. </s> <s xml:id="echoid-s2689" xml:space="preserve">Si au point H, où une tengente HI, touche l’Ellipſe on éle-<lb/>ve une pérpendiculaire HK qui aille rencontrer l’axe AB au point <lb/>K, je dis que FG eſt à GK comme le quarré de AF eſtau quarré de <lb/>FD, ou, ce qui revient au même, comme le rectangle de AG par <lb/>GB eſt au quarré GH.</s> <s xml:id="echoid-s2690" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2691" xml:space="preserve">Pour le prouver, conſiderés que les triangles IGH & </s> <s xml:id="echoid-s2692" xml:space="preserve">GHK, ſont <lb/>ſemblables, par conſéquent IG ({aa-xx/x}), GH (yy) : </s> <s xml:id="echoid-s2693" xml:space="preserve">: </s> <s xml:id="echoid-s2694" xml:space="preserve">GH <lb/>(y); </s> <s xml:id="echoid-s2695" xml:space="preserve">GK{(yy)/aa-xx;</s> <s xml:id="echoid-s2696" xml:space="preserve">/x} ou ce qui eſt la même choſe {yyx/aa-xx}; </s> <s xml:id="echoid-s2697" xml:space="preserve">comme <lb/>nous avons l’expreſſion de KG, il n’eſt donc queſtion que de prouver <lb/>que GF (x) eſt à GK ({yyx/aa-xx}) commele rectangle de AG par GB <lb/>(aa-xx) eſt au quarré de GH (yy), ce qui eſt bien évident, puiſ-<lb/>que le produit des extrémes & </s> <s xml:id="echoid-s2698" xml:space="preserve">celui des moyens donnent l’un & </s> <s xml:id="echoid-s2699" xml:space="preserve"><lb/>l’autre yyx; </s> <s xml:id="echoid-s2700" xml:space="preserve">car on remarquera que c’eſt multiplier le ſecond terme <lb/>yyx par aa-xx que de ne le pas diviſer par la même quantité.</s> <s xml:id="echoid-s2701" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2702" xml:space="preserve">Comme les propriétés de l’Ellipſe ſont toujours les mêmes, ſoit <lb/>que la tengente aille rencontrer le grand axe AB prolongé, ou le <lb/>petit axe DE auſſi prolongé, l’on verra par une démonſtration ſem-<lb/>blable à la précédente, que ſi la perpendiculaire élevée ſur la tengen-<lb/>te IO alloit rencontrer le petit axe ED au point L, l’on auroit encore <lb/>le quarré de EF eſt au quarré de AF comme la coupée MF eſt à la <lb/>ligne ML.</s> <s xml:id="echoid-s2703" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div188" type="section" level="2" n="31"> <head xml:id="echoid-head144" xml:space="preserve"><emph style="sc">Corollaire</emph> <emph style="sc">Premier</emph>.</head> <p> <s xml:id="echoid-s2704" xml:space="preserve">28. </s> <s xml:id="echoid-s2705" xml:space="preserve">Il ſuit du premier principe, que quand on connoîtra les deux <lb/>diamêtres AB & </s> <s xml:id="echoid-s2706" xml:space="preserve">ED d’une Ellipſe, & </s> <s xml:id="echoid-s2707" xml:space="preserve">la diſtance du centre F au point <lb/>G où on aura mené une ordonnée GH, qu’on connoîtra toujours <lb/>la valeur de cette ordonnée en nombre, en diſant ſi le quarré du <lb/>demi diamêtre AF donne tant pour le quarré du diamêtre FD, que <lb/>donnera la difference du quarré de AF au quarré FG, pour le quarré <lb/>GH que l’on cherche? </s> <s xml:id="echoid-s2708" xml:space="preserve">lequel étant trouvé, on n’aura qu’à en ex-<lb/>traire la racine quarrée, qui ſera la perpendiculaire GH.</s> <s xml:id="echoid-s2709" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div189" type="section" level="2" n="32"> <head xml:id="echoid-head145" xml:space="preserve"><emph style="sc">Corollaire</emph> <emph style="sc">Second</emph>.</head> <p> <s xml:id="echoid-s2710" xml:space="preserve">29. </s> <s xml:id="echoid-s2711" xml:space="preserve">Il ſuit auſſi du troiſiéme principe, que ſi on avoit beſoin de <pb o="32" file="0140" n="143" rhead="LA SCIENCE DES INGENIEURS,"/> connoître la valeur de la partie ML, compriſe entre l’ordonnée HM <lb/>& </s> <s xml:id="echoid-s2712" xml:space="preserve">la perpendiculaire HL élevée à l’extremité de la tengente IH, <lb/>on n’aura qu’à dire ſi le quarré EF donne le quarré FB, que don-<lb/>nera la ligne FM pour la valeur de la ligne ML; </s> <s xml:id="echoid-s2713" xml:space="preserve">ce qu’on trouvera <lb/>en faiſant la régle.</s> <s xml:id="echoid-s2714" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div190" type="section" level="2" n="33"> <head xml:id="echoid-head146" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s2715" xml:space="preserve">30. </s> <s xml:id="echoid-s2716" xml:space="preserve">Comme l’on ne parvient avec le ſecours de l’Algebre à la <lb/> <anchor type="note" xlink:label="note-0140-01a" xlink:href="note-0140-01"/> connoiſſance des grandeurs que l’on cherche, que par le moyen <lb/>de celles que l’on connoît déja, il faut néceſſairement, pour déter-<lb/>miner l’épaiſſeur des piés-droits qui ſoûtiennent les Voûtes Ellipti-<lb/>ques, connoître certaines lignes qu’on ne peut avoir que mécani-<lb/>quement (c’eſt-à-dire) en traçant une demi Ellipſe ſemblable à celle <lb/>dont on veut faire la Voûte; </s> <s xml:id="echoid-s2717" xml:space="preserve">& </s> <s xml:id="echoid-s2718" xml:space="preserve">comme les Ellipſes en pareil cas ne <lb/>ſauroient être trop grandes, afin d’avoir ce que l’on demande avec <lb/>plus de préciſion; </s> <s xml:id="echoid-s2719" xml:space="preserve">voici comme on s’y prendra.</s> <s xml:id="echoid-s2720" xml:space="preserve"/> </p> <div xml:id="echoid-div190" type="float" level="3" n="1"> <note position="left" xlink:label="note-0140-01" xlink:href="note-0140-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> <p> <s xml:id="echoid-s2721" xml:space="preserve">Ayant tracé ſur le parquet d’une Chambre ou ſur une grande <lb/>Table uneligne AB de 5 à 6 pieds de longueur, pour ſervir de grand <lb/>axe, on la diviſera en deux également au point D, & </s> <s xml:id="echoid-s2722" xml:space="preserve">à ce point <lb/>on élevera la perpendiculaire DC dont la longueur doit avoir le <lb/>même raport avec la ligne AB, que la hauteur de la Voûte dans œu-<lb/>vre qu’on ſe propoſe de faire, aura avec ſa largeur: </s> <s xml:id="echoid-s2723" xml:space="preserve">enſuite il faut <lb/>tirer les lignes CE & </s> <s xml:id="echoid-s2724" xml:space="preserve">EF, enſorte qu’elles ſoient chacune égales à la <lb/>moitié du grand axe AB, afin d’avoir les points E & </s> <s xml:id="echoid-s2725" xml:space="preserve">F, qui ſeront <lb/>les foyers de l’Ellipſe: </s> <s xml:id="echoid-s2726" xml:space="preserve">après cela, l’on aura de la ficelle bien fine <lb/>& </s> <s xml:id="echoid-s2727" xml:space="preserve">bien unie ou un cordon de ſoye, & </s> <s xml:id="echoid-s2728" xml:space="preserve">on prendra dans cette ficelle <lb/>une longueur qui ſoit parfaitement égale à l’axe AB, on attachera <lb/>les deux extrêmités de cette longueur aux points E & </s> <s xml:id="echoid-s2729" xml:space="preserve">F, & </s> <s xml:id="echoid-s2730" xml:space="preserve">on ſe <lb/>ſervira d’un poinçon pour tenir la ficelle tenduë, avec lequel on <lb/>tracera en même tems la courbe AGHB en allant du point A au <lb/>point C, & </s> <s xml:id="echoid-s2731" xml:space="preserve">du point C au point B; </s> <s xml:id="echoid-s2732" xml:space="preserve">car l’on entend bien que cette <lb/>ficelle doit gliſſer autour du poinçon G, & </s> <s xml:id="echoid-s2733" xml:space="preserve">qu’elle doit être toûjours <lb/>également tenduë: </s> <s xml:id="echoid-s2734" xml:space="preserve">cette maniere de tracer l’Ellipſe eſt la plus com-<lb/>mode que je ſache; </s> <s xml:id="echoid-s2735" xml:space="preserve">j’ay jugé à propos de la raporter ici, quoiqu’elle <lb/>ſoit aſſés connue; </s> <s xml:id="echoid-s2736" xml:space="preserve">mais ce n’eſt point un mal de rendre les choſes <lb/>préſentes, quand on rencontre les occaſions d’en faire uſage.</s> <s xml:id="echoid-s2737" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2738" xml:space="preserve">L’Ellipſe étant tracée, il faut faire une échelle & </s> <s xml:id="echoid-s2739" xml:space="preserve">avoir égard à la <lb/> <anchor type="note" xlink:label="note-0140-02a" xlink:href="note-0140-02"/> quantité des pieds qu’on veut donner de largeur à la Voûte; </s> <s xml:id="echoid-s2740" xml:space="preserve">ſic’eſt <lb/>par exemple 24 pieds, je diviſe la ligne AB en quatre parties égales <lb/>& </s> <s xml:id="echoid-s2741" xml:space="preserve">une de ces parties étant diviſée en pieds, pouces, & </s> <s xml:id="echoid-s2742" xml:space="preserve">lignes, on <lb/>connoîtra la valeur des lignes qu’on ſera obligé de tracer dans <pb o="33" file="0141" n="144" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> l’Ellipſe. </s> <s xml:id="echoid-s2743" xml:space="preserve">Par exemple, ſi on avoit quelque raiſon pour abaiſſer du <lb/>point H, pris ſur la courbe la perpendiculaire HI, à l’axe AB, <lb/>on pourra avec l’échelle trouver la valeur de la coupée DI, & </s> <s xml:id="echoid-s2744" xml:space="preserve">de <lb/>l’ordonnée IH, en pieds pouces & </s> <s xml:id="echoid-s2745" xml:space="preserve">lignes auſſi exactement qu’on <lb/>peut le déſirer dans la Pratique. </s> <s xml:id="echoid-s2746" xml:space="preserve">Nous allons faire uſage de tout <lb/>ceci.</s> <s xml:id="echoid-s2747" xml:space="preserve"/> </p> <div xml:id="echoid-div191" type="float" level="3" n="2"> <note position="left" xlink:label="note-0140-02" xlink:href="note-0140-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> </div> <div xml:id="echoid-div193" type="section" level="2" n="34"> <head xml:id="echoid-head147" xml:space="preserve">PROPOSITION PREMIERE.</head> <head xml:id="echoid-head148" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <head xml:id="echoid-head149" style="it" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux piés-droits d’une <lb/>voûte Elliptique.</head> <p> <s xml:id="echoid-s2748" xml:space="preserve">31. </s> <s xml:id="echoid-s2749" xml:space="preserve">Comme la pouſſée d’une Voûte ſe fait toujours ſelon les di-<lb/> <anchor type="note" xlink:label="note-0141-01a" xlink:href="note-0141-01"/> rections des tangentes menées à la courbe qu’elle forme, il faut com-<lb/>mencer par diviſer le quart d’Ellipſe BD, en deux également au <lb/>point L, pour mener à ce point la tangente LO, & </s> <s xml:id="echoid-s2750" xml:space="preserve">ſur l’extrêmité <lb/>L, lá perpendiculaire LA, qui étant prolongée juſqu’en F, parta-<lb/>gera comme à l’ordinaire la demi Voûte en deux parties à peu-près <lb/>égales; </s> <s xml:id="echoid-s2751" xml:space="preserve">alors la ligne FA, pourra être regardée comme le plan in-<lb/>cliné ſur lequel agit le vouſſoir FGDL, & </s> <s xml:id="echoid-s2752" xml:space="preserve">la ligne OL, comme la <lb/>direction de la puiſſance qui ſeroit en équilibre avec l’action du <lb/>même vouſſoir: </s> <s xml:id="echoid-s2753" xml:space="preserve">on ſera peut-être ſurpris que cette direction ne ſoit <lb/>pas perpendiculaire ſur le milieu du joint FL, comme dans lespro-<lb/>blémes précédents; </s> <s xml:id="echoid-s2754" xml:space="preserve">mais comme il falloit neceſſairement qu’elleré-<lb/>pondit au point L, pour avoir les lignes LK, LV, KA, nous avons <lb/>été obligé d’en uſer ainſi afin d’agir avec plus de préciſion, mais <lb/>nous y aurons égard dans l’application; </s> <s xml:id="echoid-s2755" xml:space="preserve">ainſi ſupoſant les autres li-<lb/>gnes tirées comme ci-devant, nous nommerons LK, a; </s> <s xml:id="echoid-s2756" xml:space="preserve">KA, b; <lb/></s> <s xml:id="echoid-s2757" xml:space="preserve">LA, c; </s> <s xml:id="echoid-s2758" xml:space="preserve">BV, d; </s> <s xml:id="echoid-s2759" xml:space="preserve">BS, f; </s> <s xml:id="echoid-s2760" xml:space="preserve">MP, g; </s> <s xml:id="echoid-s2761" xml:space="preserve">ZB, y; </s> <s xml:id="echoid-s2762" xml:space="preserve">& </s> <s xml:id="echoid-s2763" xml:space="preserve">le vouſſoir CG, ou CE, <lb/>nn.</s> <s xml:id="echoid-s2764" xml:space="preserve"/> </p> <div xml:id="echoid-div193" type="float" level="3" n="1"> <note position="right" xlink:label="note-0141-01" xlink:href="note-0141-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> <p> <s xml:id="echoid-s2765" xml:space="preserve">Cela poſé, je conſidere que les triangles LKA & </s> <s xml:id="echoid-s2766" xml:space="preserve">LMN, étant <lb/>ſemblables donnent AK (b), LK (a):</s> <s xml:id="echoid-s2767" xml:space="preserve">: LM (y+d), MN({ay+ad/b}) <lb/>par conſequent NP ſera {gb-ad-ay/b}, & </s> <s xml:id="echoid-s2768" xml:space="preserve">commelestriangles LKA <lb/>& </s> <s xml:id="echoid-s2769" xml:space="preserve">NOP, ſont encore ſemblables on aura auſſi LA(c), AK (b):</s> <s xml:id="echoid-s2770" xml:space="preserve">: NP <lb/>({gb-ad-ay/b}), PO ({gb-ad-ay/c}) qui donne l’expreſſion du <pb o="34" file="0142" n="145" rhead="LA SCIENCE DES INGENIEURS,"/> bras de lévier PO, preſentement pour avoir l’expreſſion de la puiſ-<lb/>ſance O, je conſidere que la peſanteur abſoluë du vouſſoir LGD, <lb/>eſt à ſon effort ſur le joint FL, comme LK (a) eſt à LA (c), & </s> <s xml:id="echoid-s2771" xml:space="preserve"><lb/>qu’ainſi il faudra multiplier {cnn/a} par le bras de lévier PO, qui donne <lb/>{gbnn/a}-nnd-nny pour l’expreſſion de la pouſſée de la Voûte par <lb/>raport au point d’apui P, d’un autre côté pour avoir celle de la ré-<lb/>ſiſtance du pié-droit PB, jointe au vouſſoir FB, je multiplie le <lb/>rectangle PB (fy) par PT ({y/2}) & </s> <s xml:id="echoid-s2772" xml:space="preserve">la ſuperficie du vouſſoir FB (nn) <lb/>par le bras de lévier PS (y); </s> <s xml:id="echoid-s2773" xml:space="preserve">(car je ſupoſe que la ligne de direc-<lb/>tion tirée du centre de gravité Q, tombe à peu-près au point S, ce <lb/>vouſſoir étant beaucoup plus incliné que dans la Voûte en plein <lb/>ceintre) ainſi ajoûtant ces deux produits enſemble pour les com-<lb/>parer avec la pouſſée de la Voûte, il vient cette équation {gbnn/a} <lb/>-dnn-nny={fyy/2}+nny, laquelle étant réduite, diviſée par f, <lb/>& </s> <s xml:id="echoid-s2774" xml:space="preserve">multipliée par 2, il vient {2gbnn/af}-{2dnn/f}=yy-{4nny/f}: </s> <s xml:id="echoid-s2775" xml:space="preserve">or chan-<lb/>geant le ſecond membre en un quarré parfait, & </s> <s xml:id="echoid-s2776" xml:space="preserve">dégageant l’in-<lb/>connu, on aura {2gbnn/af}-{2dnn/f}+{4n+/ff}-{2nn/f}=y, qui donne ce <lb/>que l’on cherche.</s> <s xml:id="echoid-s2777" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div195" type="section" level="2" n="35"> <head xml:id="echoid-head150" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s2778" xml:space="preserve">Pour raporter le Probleme précédent à la pratique, il faut com-<lb/>mencer par tracer une grande Ellipſe comme on l’a enſeigné dans <lb/>l’Article 36. </s> <s xml:id="echoid-s2779" xml:space="preserve">Enſorte que les deux demi axes ſoient dans la raiſon <lb/>des lignes HB & </s> <s xml:id="echoid-s2780" xml:space="preserve">HD; </s> <s xml:id="echoid-s2781" xml:space="preserve">par exemple ſi la largeur de la Voûte dans <lb/>œuvre étoit de 24 pieds, & </s> <s xml:id="echoid-s2782" xml:space="preserve">que la hauteur DH, fut les deux tiers <lb/> <anchor type="note" xlink:label="note-0142-01a" xlink:href="note-0142-01"/> de cette même largeur, BH ſeroit de 12 pieds, & </s> <s xml:id="echoid-s2783" xml:space="preserve">DH de huit; </s> <s xml:id="echoid-s2784" xml:space="preserve">or <lb/>diviſant un quart de cette Ellipſe en deux également, on abbaiſſera <lb/>du point de diviſion une perpendiculaire comme LV, dont il ſera <lb/>aiſé de connoître la valeur par le moyen de l’échelle auſſi-bien que <lb/>de la ligne VH ou LK, ayant donc fait moi-même ce que je viens <lb/>de dire, j’ai trouvé que LV ou KH, étoit de 6 pieds 3 pouces, <lb/>& </s> <s xml:id="echoid-s2785" xml:space="preserve">que LK ou VH, étoit de 7 pieds 6 pouces; </s> <s xml:id="echoid-s2786" xml:space="preserve">& </s> <s xml:id="echoid-s2787" xml:space="preserve">comme il faloit <lb/>auſſi connoître KA, j’ai dit ſelon l’Article 29. </s> <s xml:id="echoid-s2788" xml:space="preserve">comme le quarré de <lb/>DA eſt au quarré de HB, de même la ligne KH eſt à la ligne KA, <lb/>que j’ai trouvée de 14 pieds 9 lignes.</s> <s xml:id="echoid-s2789" xml:space="preserve"/> </p> <div xml:id="echoid-div195" type="float" level="3" n="1"> <note position="left" xlink:label="note-0142-01" xlink:href="note-0142-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> <pb o="35" file="0143" n="146" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> <p> <s xml:id="echoid-s2790" xml:space="preserve">La Voûte étant ſupoſée de 3 pieds d’épaiſſeur, pour avoir la ſu-<lb/>perficie des voſſoirs FD ou FB, j’ai cherché celle de la grande <lb/>& </s> <s xml:id="echoid-s2791" xml:space="preserve">la petite Ellipſe <anchor type="note" xlink:href="" symbol="*"/>, & </s> <s xml:id="echoid-s2792" xml:space="preserve">ayant retranché l’une de l’autre, j’ai pris la <anchor type="note" xlink:label="note-0143-01a" xlink:href="note-0143-01"/> huitiéme partie de la difference qui m’a donné 27 pieds; </s> <s xml:id="echoid-s2793" xml:space="preserve">ainſi ſu-<lb/>poſant la hauteur du pié-droit de 15 pieds, on aura la valeur de <lb/>toutes les lettres qui ſe trouvent dans l’équation précédente, puiſ-<lb/>que LK (a) ſera de 7 pieds 6 pouces, KA(b) de 14 pieds 9 lignes, <lb/>BV (d) de 4 pieds 6 pouces, ZP (f) de 15 pieds, MP (g) de <lb/>21 pieds 3 pouces; </s> <s xml:id="echoid-s2794" xml:space="preserve">à quoi il faut ajoûter la moitié de l’épaiſſeur de <lb/>la Voûte pour avoir 22 pieds 9 pouces, & </s> <s xml:id="echoid-s2795" xml:space="preserve">CG (nn) de 27 pieds: <lb/></s> <s xml:id="echoid-s2796" xml:space="preserve">ainſi ayant fait les mêmes opérations avec les nombres que celles <lb/>qui ſont indiquées dans la derniere équation, j’ai trouvé que y, c’eſt-<lb/>à-dire l’épaiſſeur des piés-droits, devoit être de 8 pieds 8 pouces.</s> <s xml:id="echoid-s2797" xml:space="preserve"/> </p> <div xml:id="echoid-div196" type="float" level="3" n="2"> <note symbol="*" position="right" xlink:label="note-0143-01" xlink:href="note-0143-01a" xml:space="preserve">V. le C. <lb/>Art. 574.</note> </div> <p style="it"> <s xml:id="echoid-s2798" xml:space="preserve">La tengente LO donnant un bras de lévier OP plus court que ſi la <lb/>ligne de direction de la puiſſance étoit perpendiculaire ſur le milieu du <lb/>joint FL, comme eſt par exemple CX, j’ai augmenté la valeur de la <lb/>ligne MP, de la moitié de l’épaiſſeur de la Voûte, afin que le bras de <lb/>lévier PO, ſe trouvant allongé de la ligne XO égal à CL, cette ſolu-<lb/>tion répondit à peu près aux autres précédentes.</s> <s xml:id="echoid-s2799" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div198" type="section" level="2" n="36"> <head xml:id="echoid-head151" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s2800" xml:space="preserve">32. </s> <s xml:id="echoid-s2801" xml:space="preserve">On voit que les Voûtes ſurbaiſſées ont plus de pouſſée que <lb/> <anchor type="note" xlink:label="note-0143-02a" xlink:href="note-0143-02"/> celles qui ſont en plain ceintre; </s> <s xml:id="echoid-s2802" xml:space="preserve">car comme l’angle OLV formé par <lb/>la ligne de direction OL & </s> <s xml:id="echoid-s2803" xml:space="preserve">la perpendiculaire LV, eſt plus grand <lb/>que dans les profils précédents, il arrive que le bras de lévier PO, <lb/>ſe trouve alongé, ce qui doit augmenter la force de la puiſſance <lb/>agiſſante: </s> <s xml:id="echoid-s2804" xml:space="preserve">or comme plus le demi axe DH, ſera petit eû égard à <lb/>l’autre HB, plus le bras de lévier PO augmentera, il s’enſuit que <lb/>plus une Voûte eſt ſurbaiſſée & </s> <s xml:id="echoid-s2805" xml:space="preserve">plus elle a de pouſſée.</s> <s xml:id="echoid-s2806" xml:space="preserve"/> </p> <div xml:id="echoid-div198" type="float" level="3" n="1"> <note position="right" xlink:label="note-0143-02" xlink:href="note-0143-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>5. <lb/><emph style="sc">Fig</emph>. 8.</note> </div> </div> <div xml:id="echoid-div200" type="section" level="2" n="37"> <head xml:id="echoid-head152" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s2807" xml:space="preserve">33. </s> <s xml:id="echoid-s2808" xml:space="preserve">Il eſt bon d’obſerver auſſi que les vouſſoirs qui compoſent <lb/>une Voûte ſurbaiſſée devant avoir neceſſairement pluſieurs centres, <lb/>cette Voûte n’eſt pas à beaucoup près ſi forte que celle en plein <lb/>ceintre, parce que, dans cette derniere, l’effort de tous les vouſ-<lb/>ſoirs ſe réüniſſant à un ſeul point, ils ſe fortifient mutuellement, <lb/>& </s> <s xml:id="echoid-s2809" xml:space="preserve">ſont capables de mieux ſoûtenir l’action de quelque grand far-<lb/>deau ou de quelque choc violent, comme ſeroit celui des bom-<lb/>bes; </s> <s xml:id="echoid-s2810" xml:space="preserve">ainſi quand il eſt queſtion des ſoûterains qu’on veut mettre à <pb o="36" file="0144" n="147" rhead="LA SCIENCE DES INGENIEURS,"/> l’épreuve, il n’y a point de Voûte qui convienne mieux que celle <lb/>en plein ceintre.</s> <s xml:id="echoid-s2811" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div201" type="section" level="2" n="38"> <head xml:id="echoid-head153" xml:space="preserve">PROPOSITION SECONDE.</head> <head xml:id="echoid-head154" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s2812" xml:space="preserve">Trouver quelle épaiſſeur il faut donner aux piés-droits <lb/>des Voûtes en tiers-points pour être en équilibre avec la pouſ-<lb/>ſée des mêmes Voûtes.</s> <s xml:id="echoid-s2813" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2814" xml:space="preserve">34. </s> <s xml:id="echoid-s2815" xml:space="preserve">L’on ſait que la Voûte en tiers-point ou Gothique, étant for-<lb/> <anchor type="note" xlink:label="note-0144-01a" xlink:href="note-0144-01"/> mée par deux arcs de cercle égaux, cette Voûte doit avoir neceſ-<lb/>ſairement deux centres dont la poſition dépend de l’élevation qu’on <lb/>veut lui donner: </s> <s xml:id="echoid-s2816" xml:space="preserve">par exemple, ſi la ligne BI, détermine la largeur <lb/>de la Voûte, les centres peuvent être aux points B & </s> <s xml:id="echoid-s2817" xml:space="preserve">I, ou à quel-<lb/>qu’autres points G & </s> <s xml:id="echoid-s2818" xml:space="preserve">H, également éloignés du milieu A: </s> <s xml:id="echoid-s2819" xml:space="preserve">quand <lb/>on prend les points B & </s> <s xml:id="echoid-s2820" xml:space="preserve">I pour centre, la largeur BI, devient le <lb/>raïon avec lequel on décrit les deux arcs, & </s> <s xml:id="echoid-s2821" xml:space="preserve">alors la Voûte eſt auſſi <lb/>élevée qu’on a coûtume de la faire quand il s’agit d’une Egliſe ou <lb/>de quelque bâtiment civil; </s> <s xml:id="echoid-s2822" xml:space="preserve">mais, s’il eſt queſtion d’un Magaſin qu’on <lb/>veut mettre à l’épreuve de la bombe, on ſe garde bien de lui <lb/>donner tant d’élevation, parce qu’elle ſeroit trop foible. </s> <s xml:id="echoid-s2823" xml:space="preserve">La ma-<lb/>niere la plus convenable eſt de diviſer les lignes AI & </s> <s xml:id="echoid-s2824" xml:space="preserve">AB, en deux <lb/>parties égales aux points H & </s> <s xml:id="echoid-s2825" xml:space="preserve">G pour avoir les centres ſervant à <lb/>décrire les arcs BD & </s> <s xml:id="echoid-s2826" xml:space="preserve">DI avec les raïons HB & </s> <s xml:id="echoid-s2827" xml:space="preserve">GI; </s> <s xml:id="echoid-s2828" xml:space="preserve">ainſi ſupoſant <lb/>que la Voûte, ſur laquelle nous allons opérer, ait été tracée de <lb/>cette maniere, on diviſera l’arc BCD en deux également au point <lb/>C, enſuite on tirera les raïons HF, HT, la corde BD, & </s> <s xml:id="echoid-s2829" xml:space="preserve">les autres <lb/>lignes comme à l’ordinaire.</s> <s xml:id="echoid-s2830" xml:space="preserve"/> </p> <div xml:id="echoid-div201" type="float" level="3" n="1"> <note position="left" xlink:label="note-0144-01" xlink:href="note-0144-01a" xml:space="preserve"><emph style="sc">Plan</emph>. 6. <lb/><emph style="sc">Fig</emph>. 1.</note> </div> <p> <s xml:id="echoid-s2831" xml:space="preserve">Ayant nommé LK a; </s> <s xml:id="echoid-s2832" xml:space="preserve">KQ b; </s> <s xml:id="echoid-s2833" xml:space="preserve">LQ c; </s> <s xml:id="echoid-s2834" xml:space="preserve">BV d; </s> <s xml:id="echoid-s2835" xml:space="preserve">ZP f; </s> <s xml:id="echoid-s2836" xml:space="preserve">MP g; </s> <s xml:id="echoid-s2837" xml:space="preserve">ZB y; <lb/></s> <s xml:id="echoid-s2838" xml:space="preserve">ML ſeray + d; </s> <s xml:id="echoid-s2839" xml:space="preserve">cela poſé, remarquez queles triangles LK Q & </s> <s xml:id="echoid-s2840" xml:space="preserve">LMN <lb/>étant ſemblables, l’on aura KQ (b), KL (a):</s> <s xml:id="echoid-s2841" xml:space="preserve">: LM (d + y) <lb/>MN ({ad + ay/b}), ainſi la ligne NP ſera {bg-ad-ay/b}: </s> <s xml:id="echoid-s2842" xml:space="preserve">& </s> <s xml:id="echoid-s2843" xml:space="preserve">com-<lb/>me le triangle LKQ eſt auſſi ſemblable à NOP, on aura encore <lb/>LQ (c), KQ (b):</s> <s xml:id="echoid-s2844" xml:space="preserve">: NP ({bg-ad-ay/b}), PO ({bg-ad-ay/c}).</s> <s xml:id="echoid-s2845" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2846" xml:space="preserve">Préſentement, faites attention que dans le triangle rectangle <lb/>LKQ le côté LK, peut exprimer la peſanteur abſoluë du vouſſoir <pb o="37" file="0145" n="148" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> LDT, puiſque la ligne de direction tirée de ſon centre de gravité <lb/>eſt coupée en angle droit par ce côté de même la ligne de direction <lb/>OL de la puiſſance O, étant perpendiculaire ſur le côté LQ, il ex-<lb/>primera le fort du vouſſoir ſur le joint FC: </s> <s xml:id="echoid-s2847" xml:space="preserve">ainſi nommant nn, la <lb/>ſuperficie de ce vouſſoir, ſon effort ſera encore {cnn/a}, qui étant mul-<lb/>tiplié par le bras de lévier PO, l’on aura {bgnn/a} - dnn - nny, pour <lb/>la pouſſée de la Voûte par raport au point d’apui P: </s> <s xml:id="echoid-s2848" xml:space="preserve">d’un autre côté <lb/>ſi l’on ſupoſe que la ligne de direction tirée du centre de gravite du <lb/>vouſſoir LFB vient tomber au point S, afin de rendre le calcul plus <lb/>ſimple, la réſiſtance du pié-droit joint au vouſſoir qui lui répond, <lb/>ſera exprimée comme ci-devant par{fyy/2} + nny, qui étant comparé <lb/>avec la pouſſée de la Voûte l’on aura dans l’état d’équilibre {bgnn/a} <lb/>- dnn - nny = {fyy/2} + nny, d’où on tirera comme à l’ordinaire <lb/>√{2bgnn/af}-{2dnn/f}+{4n<emph style="sub">4</emph>/ff}\x{0020}-{2nn/f} = y.</s> <s xml:id="echoid-s2849" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div203" type="section" level="2" n="39"> <head xml:id="echoid-head155" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s2850" xml:space="preserve">Pour raporter ce Probléme à la pratique, nous ſupoſerons que <lb/>la ligne BI eſt de 24 pieds: </s> <s xml:id="echoid-s2851" xml:space="preserve">cela étant HB ou HD ſera de 18 pieds, <lb/>& </s> <s xml:id="echoid-s2852" xml:space="preserve">AH de 6, ainſi dans le triangle rectangle ADH dont on connoît <lb/>deux côtés, il ſera aiſé de connoître l’angle AHD, qu’on trouvera <lb/>de 70 degrés 30 minutes, dont la moitié ſera pour l’angle LHV du <lb/>triangle rectangle LVH duquell’on connoît le côté LH, carla Voûte <lb/>aïant trois pieds d’épaiſſeur, ce côté ſera de 19 pieds & </s> <s xml:id="echoid-s2853" xml:space="preserve">demi; </s> <s xml:id="echoid-s2854" xml:space="preserve">ainſi <lb/>comme nous avons un triangle rectangle dans lequel on connoît <lb/>deux angles & </s> <s xml:id="echoid-s2855" xml:space="preserve">un côté, on trouvera par le calcul ordinaire que LV <lb/>eſt de 11 pieds 3 pouces, & </s> <s xml:id="echoid-s2856" xml:space="preserve">VH d’environ 16 pieds, d’où retran-<lb/>chant AH de ſix, il en reſtera 10 pour VA, ou LK: </s> <s xml:id="echoid-s2857" xml:space="preserve">ainſi connoiſ-<lb/>ſant un des côtés du triangle rectangle LKQ avec l’angle aigu LQK <lb/>(puiſqu’il eſt complement de l’angle AHQ) on trouvera que le <lb/>côté KQ eſt à peu-près de 7 pieds, deſorte que ſi l’on ſupoſe que <lb/>la hauteur du pié-droit eſt encore de 15 pieds, on aura la valeur <lb/>de toutes les lettres excepté nn; </s> <s xml:id="echoid-s2858" xml:space="preserve">car LA (a) ſera de 10 pieds, KQ <lb/>(b) de 7, BV (d) de 2, ZP (f) de 15, à quoi ajoûtant LV ou <lb/>MZ, qu’on a trouvé de 11 pieds 3 pouces, on aura 16 pieds 3 pou-<lb/>ces pour MP (g).</s> <s xml:id="echoid-s2859" xml:space="preserve"/> </p> <pb o="38" file="0146" n="149" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s2860" xml:space="preserve">Comme il nous reſte à trouver la valeur de nn, je cherche la <lb/>ſuperficie des cercles qui auroient pour raïon HB & </s> <s xml:id="echoid-s2861" xml:space="preserve">HE; </s> <s xml:id="echoid-s2862" xml:space="preserve">c’eſt-à-<lb/>dire 18 & </s> <s xml:id="echoid-s2863" xml:space="preserve">21 pieds, & </s> <s xml:id="echoid-s2864" xml:space="preserve">après les avoir trouvé j’en prend la diffe-<lb/>rence qui eſt de 368 pieds quarrés qui eſt la valeur de la couronne, <lb/>dont la ſuperficie du vouſſoir LDT fait partie. </s> <s xml:id="echoid-s2865" xml:space="preserve">Or pour avoir cette <lb/>partie, je dis, comme 360 degrés valeur de la circonférence du <lb/>cercle eſt à 35 dégrés 15 minutes, valeur de l’arc FT; </s> <s xml:id="echoid-s2866" xml:space="preserve">ainſi 368 pieds <lb/>difference de deux cercles, eſt à la ſuperficie CFTD, qu’on trou-<lb/>vera de 35 pieds 9 pouces 4 lignes, faiſant les opérations indiquées <lb/>dans l’équation {2bgnn/af} - {2dnn/f} + {4n+/ff} - {2nn/f} = y. </s> <s xml:id="echoid-s2867" xml:space="preserve">On trouvera que <lb/>la valeur de y, c’eſt-à-dire l’épaiſſeur des piés-droits, doit être de <lb/>5 pieds 3 pouces.</s> <s xml:id="echoid-s2868" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2869" xml:space="preserve">Quoique la perpendiculaire AX & </s> <s xml:id="echoid-s2870" xml:space="preserve">le raïon HT ſe coupent au <lb/>point D & </s> <s xml:id="echoid-s2871" xml:space="preserve">forme l’angle TDX, qui comprend un petit eſpace <lb/>qui rend le vouſſoir ſuperieur LX plus grand que l’inferieur LEB, <lb/>je n’ai pas laiſſé que deles conſidérer égaux, parce que la difference <lb/>eſt trop peu de choſe pour y avoir égard dans la pratique.</s> <s xml:id="echoid-s2872" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div204" type="section" level="2" n="40"> <head xml:id="echoid-head156" style="it" xml:space="preserve">Remarque prémiere.</head> <p> <s xml:id="echoid-s2873" xml:space="preserve">35. </s> <s xml:id="echoid-s2874" xml:space="preserve">On remarquera que les Voûtes en tiers-points ont beaucoup <lb/>moins de pouſſée que celles qui ſont en plein ceintre, parce que <lb/>la ligne de direction OL de la puiſſance qui ſoûtiendroit le vouſſoir <lb/>LTD, faiſant un plus petit angle avec la verticale LV, que dans la <lb/>Voûte en plein ceintre il faut neceſſairement que le bras de lévier <lb/>PO, ſoit plus court que ſi la Voûte étoit moins élevée, tellement <lb/>qu’on peut dire que plus le raïon HB de l’arc BD ſera grand & </s> <s xml:id="echoid-s2875" xml:space="preserve"><lb/>moins il faudra donner d’épaiſſeur aux piés-droits.</s> <s xml:id="echoid-s2876" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div205" type="section" level="2" n="41"> <head xml:id="echoid-head157" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s2877" xml:space="preserve">36. </s> <s xml:id="echoid-s2878" xml:space="preserve">Si les Voûtes en tiers-points ou les ſurbaiſſées avoient leurs <lb/>extradoſes dirigées en pente, on trouvera toûjours l’épaiſſeur de <lb/>leurs piés-droits comme on a fait dans l’Article 13. </s> <s xml:id="echoid-s2879" xml:space="preserve">puiſque les opé-<lb/>rations ne differeront en rien de celles qu’on vient de voir dans les <lb/>deux propoſitions précédentes, il n’y aura ſeulement que la ſeule <lb/>expreſſion nn du vouſſoir qui pourra valoir un plus grand nombre <lb/>de pieds quarrès.</s> <s xml:id="echoid-s2880" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2881" xml:space="preserve">De même, ſi on vouloit que les pieds-droits de ces deux eſpeces <lb/>de Voûtes fuſſent accompagnés de contreforts, on ſuivra ce qui <pb o="39" file="0147" n="150" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> a été enſeigné dans l’Article 20, n’ayant pas jugé à propos de répeter <lb/>ce qui a été dit à ce ſujet, pour ne point ennuïer.</s> <s xml:id="echoid-s2882" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div206" type="section" level="2" n="42"> <head xml:id="echoid-head158" xml:space="preserve">PROPOSITION TROISIE’ME.</head> <head xml:id="echoid-head159" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s2883" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux-piés-droits qui <lb/>ſoûtiendroient une Plate-Bande.</s> <s xml:id="echoid-s2884" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2885" xml:space="preserve">37. </s> <s xml:id="echoid-s2886" xml:space="preserve">La premiere choſe, dont il faut être prévenu, eſt que pour <lb/> <anchor type="note" xlink:label="note-0147-01a" xlink:href="note-0147-01"/> avoir la coupe des clavaux qui doivent compoſer une Plate-Bande, <lb/>on trace un triangle équilateral ALF ſur la ligne LF qui exprime <lb/>la largeur de la Plate-Bande, enſuite on diviſe cette largeur en au-<lb/>tant de parties égales, qu’on voit à peu-près qu’elle doit contenir <lb/>de clavaux, & </s> <s xml:id="echoid-s2887" xml:space="preserve">du point A comme centre on tire des lignes qui <lb/>paſſant par chaque point de diviſion, leſquelles allant rencontrer <lb/>GI, marquent la figure & </s> <s xml:id="echoid-s2888" xml:space="preserve">la grandeur des clavaux: </s> <s xml:id="echoid-s2889" xml:space="preserve">ainſi ſupoſant <lb/>que la platte-bande DEFL ait été conſtruite de la façon que je viens <lb/>de dire, nous en prendrons la moitié DCKL, pour être conſiderée <lb/>comme une ſeule pierre qui faiſant l’effet d’un coin dont les faces <lb/>ſeroient DA & </s> <s xml:id="echoid-s2890" xml:space="preserve">CA, agit contre le point L, pour renverſer le pié-<lb/>droit MS; </s> <s xml:id="echoid-s2891" xml:space="preserve">c’eſt pourquoi il faut abbaiſſer au point L la perpendicu-<lb/>laire LO ſur DA, pour avoir la ligne de direction de la puiſſance <lb/>qui ſoûtiendroit l’effort de la demi platte-bande DK, & </s> <s xml:id="echoid-s2892" xml:space="preserve">alors la per-<lb/>pendiculaire PO ſera comme à l’ordinaire le bras de lévier de cette <lb/>puiſſance; </s> <s xml:id="echoid-s2893" xml:space="preserve">pour en avoir l’expreſſion nous nommerons LK a; </s> <s xml:id="echoid-s2894" xml:space="preserve">par <lb/>conſequent LA ſera 2a, puiſqu’à cauſe du triangle équilateral LA eſt <lb/>double de LK, d’un autre côté KA ſera nommé b; </s> <s xml:id="echoid-s2895" xml:space="preserve">LM y; </s> <s xml:id="echoid-s2896" xml:space="preserve">MP f; <lb/></s> <s xml:id="echoid-s2897" xml:space="preserve">& </s> <s xml:id="echoid-s2898" xml:space="preserve">la ſuperficie LDCK nn; </s> <s xml:id="echoid-s2899" xml:space="preserve">cela poſé, remarquez qu’à cauſe de l’angle <lb/>droit OLA, les trois triangles AKL, LMN, NOP, ſont ſemblables: </s> <s xml:id="echoid-s2900" xml:space="preserve"><lb/>ainſi KA (b) KL (a): </s> <s xml:id="echoid-s2901" xml:space="preserve">: </s> <s xml:id="echoid-s2902" xml:space="preserve">LM (y) MN ({ay/b}) par conſequent NP <lb/>ſera {fb - ya/b} d’où l’on tire AL (2a) AK (b) : </s> <s xml:id="echoid-s2903" xml:space="preserve">: </s> <s xml:id="echoid-s2904" xml:space="preserve">PN ({fb - ay/b}). </s> <s xml:id="echoid-s2905" xml:space="preserve">PO <lb/>({fb - ay/2a}).</s> <s xml:id="echoid-s2906" xml:space="preserve"/> </p> <div xml:id="echoid-div206" type="float" level="3" n="1"> <note position="right" xlink:label="note-0147-01" xlink:href="note-0147-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>6. <lb/><emph style="sc">Fig</emph>. 2.</note> </div> <p> <s xml:id="echoid-s2907" xml:space="preserve">Si l’on fait attention que la peſanteur abſoluë de la demi plate-<lb/>bande LDCK, eſt à l’effort qu’elle fait contre le pié-droit comme <lb/>LK eſt à LA, l’on verra que LA étant double de LK, l’effort que <lb/>foûtient la puiſſance O doit être exprimée par 2nn: </s> <s xml:id="echoid-s2908" xml:space="preserve">c’eſt pourquoi <pb o="40" file="0148" n="151" rhead="LA SCIENCE DES INGENIERS,"/> multipliant cette quantité par le bras de lévier PO, l’on aura (après <lb/>la réduction) {bfnn/a} - nny, pour l’expreſſion de la pouſſée de la <lb/>plate-bande par raport au point d’apui P, qui étant comparé à la <lb/>réſiſtance des piés-droits, c’eſt-à-dire à {fyy/2}, l’on aura {bfnn/a} - nny <lb/>= {fyy/2} dans l’état d’équilibre; </s> <s xml:id="echoid-s2909" xml:space="preserve">ou bien {2bnn/a} = yy + {2nny/f} après a-<lb/>voir multiplié par 2, & </s> <s xml:id="echoid-s2910" xml:space="preserve">diviſé par f: </s> <s xml:id="echoid-s2911" xml:space="preserve">or ſi l’on change le ſecond <lb/>membre en un quarré parfait, & </s> <s xml:id="echoid-s2912" xml:space="preserve">qu’on dégage enſuite l’inconnu, il <lb/>viendra {√2bnn/a} + {n+/ff}\x{0020} - {nn/f} = y.</s> <s xml:id="echoid-s2913" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div208" type="section" level="2" n="43"> <head xml:id="echoid-head160" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s2914" xml:space="preserve">Supoſant que la hauteur LS (f) des piés-droits ſoit de 15 pieds, <lb/>que la largeur LF de la Voûte ſoit de 24, & </s> <s xml:id="echoid-s2915" xml:space="preserve">ſon épaiſſeur CK de 3, <lb/>on verra que LK (a) eſt de 12 pieds, KA (b) de 20 pieds 9 pou-<lb/>ces 4 lignes, & </s> <s xml:id="echoid-s2916" xml:space="preserve">la ſuperficie LDCK (nn) de 38 pieds 3 pouces <lb/>quarrés: </s> <s xml:id="echoid-s2917" xml:space="preserve">ainſi, faiſant les opérations qui ſont indiquées dans la der-<lb/>niere équation, elles donneront 9 pieds 2 pouces pour la valeur de <lb/>y, c’eſt-à-dire pour l’épaiſſeur des piés-droits.</s> <s xml:id="echoid-s2918" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div209" type="section" level="2" n="44"> <head xml:id="echoid-head161" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s2919" xml:space="preserve">38. </s> <s xml:id="echoid-s2920" xml:space="preserve">La plate-bande eſt de toutes les Voûtes celle qui a le plus <lb/>de pouſſée, & </s> <s xml:id="echoid-s2921" xml:space="preserve">qui a le moins de force; </s> <s xml:id="echoid-s2922" xml:space="preserve">c’eſt pourquoi elle n’eſt pas <lb/>d’uſage pour les Fortifications, ne s’employant guére que dans les <lb/>grands édifices, & </s> <s xml:id="echoid-s2923" xml:space="preserve">avec des dépenſes conſiderables, à cauſe des bar-<lb/>res de fer dont on ſe ſert pour ſoulager les piés-droits, & </s> <s xml:id="echoid-s2924" xml:space="preserve">pour lier <lb/>les clavaux enſemble.</s> <s xml:id="echoid-s2925" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2926" xml:space="preserve">S’il s’agiſſoit de quelque Porte-Cochere, il faut pour emp êcher <lb/>que la plate-bande ne porte tout le poids du mur qui ſeroit élevé <lb/>deſſus, faire un arc de décharge qui ſoit appuyé ſur les piés-droits.</s> <s xml:id="echoid-s2927" xml:space="preserve"/> </p> <pb o="41" file="0149" n="152" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div210" type="section" level="2" n="45"> <head xml:id="echoid-head162" xml:space="preserve">PROPOSITION QUATRIE’ME.</head> <head xml:id="echoid-head163" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s2928" xml:space="preserve">La péſanteur de la clef d’une Voûte en plain ceintre étant <lb/>déterminée, on demande de combien il faut augmenter celle <lb/>de chaque Vouſſoir pour qu’ils ſoûtiennent tous d’eux-mê-<lb/>me en équilibre.</s> <s xml:id="echoid-s2929" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2930" xml:space="preserve">39. </s> <s xml:id="echoid-s2931" xml:space="preserve">Nous avons fait voir dans l’article 1. </s> <s xml:id="echoid-s2932" xml:space="preserve">que tous les vouſſoirs qui <lb/> <anchor type="note" xlink:label="note-0149-01a" xlink:href="note-0149-01"/> compoſent une Voûte avoient plus ou moins de pouſſée ſelon qu’ils <lb/>étoient plus près ou plus éloignés de la clef, & </s> <s xml:id="echoid-s2933" xml:space="preserve">que cette pouſſée <lb/>allant toujours en diminuant à meſure que les plans ſur leſquels ces <lb/>vouſſoirs agiſſoient, étoient moins inclinés à l’horiſon, les vouſſoirs <lb/>ſuperieurs ne manqueroient pas d’écarter ceux qui ſont immédia-<lb/>tement au-deſſous, s’ils n’étoient entretenus par du mortier: </s> <s xml:id="echoid-s2934" xml:space="preserve">ce-<lb/>pendant comme ce ſeroit un avantage pour la ſolidité des édifices <lb/>que tous les vouſſoirs qui compoſent une Voûte ne fiſſent pas plus <lb/>d’effort les uns que les autres, juſqu’à pouvoir ſe ſoutenir d’eux-<lb/>même par leur propre poids, ſans le ſecours d’aucune matiere étran-<lb/>gere, Mr. </s> <s xml:id="echoid-s2935" xml:space="preserve">de la Hire a cherché de combien il faloit augmenter <lb/>leur peſanteur au-deſſus de celle de la clef, pour gagner par leurs <lb/>propres poids la force qu’ils avoient de moins par leur ſituation; <lb/></s> <s xml:id="echoid-s2936" xml:space="preserve">& </s> <s xml:id="echoid-s2937" xml:space="preserve">comme ce Probléme eſt aſſés curieux, j’ai crû qu’on ſeroit bien <lb/>aiſe que je le raportaſſe ici.</s> <s xml:id="echoid-s2938" xml:space="preserve"/> </p> <div xml:id="echoid-div210" type="float" level="3" n="1"> <note position="right" xlink:label="note-0149-01" xlink:href="note-0149-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 3. <lb/>& 4.</note> </div> <p> <s xml:id="echoid-s2939" xml:space="preserve">Ayant une Voûte en plain ceintre ABC, compoſée de pluſieurs <lb/>vouſſoirs égaux, ſi par le ſommet B de la clef, on tire la ligne BO <lb/>perpendiculaire au rayon GB, qu’on prolonge juſqu’à la rencontre <lb/>de BO, tousles rayons qui répondent aux lits des vouſſoirs P, Q, R, S, <lb/>&</s> <s xml:id="echoid-s2940" xml:space="preserve">c. </s> <s xml:id="echoid-s2941" xml:space="preserve">Je dis que tous ces vouſſoirs ſeront en équilibre, ſi leur péſan-<lb/>teur abſolue eſt exprimée par les lignes HK, KL, LM, MN, &</s> <s xml:id="echoid-s2942" xml:space="preserve">c.</s> <s xml:id="echoid-s2943" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2944" xml:space="preserve">Pour le prouver, remarquez que les trois puiſſances, qui appar-<lb/> <anchor type="note" xlink:label="note-0149-02a" xlink:href="note-0149-02"/> tiennent au vouſſoir P, ſont exprimées par les côtés du triangle <lb/>GHK, que celles qui apartiennent au vouſſoir Q, le ſont par ceux <lb/>du triangle GKL; </s> <s xml:id="echoid-s2945" xml:space="preserve">ainſi des autres vouſſoirs R & </s> <s xml:id="echoid-s2946" xml:space="preserve">S, dont les puiſſan-<lb/>ces ſeront toûjours repreſentées par les côtés des triangles où ils <lb/>ſont renfermés, puiſque les directions de ces puiſſances ſeront per-<lb/>pendiculaires aux côtés des triangles ou à leurs parties prolongées: <lb/></s> <s xml:id="echoid-s2947" xml:space="preserve">or ſi la peſanteur du vouſſoir P eſt exprimée par la ligne HK, & </s> <s xml:id="echoid-s2948" xml:space="preserve"><lb/>celle du vouſſoir Q par la ligne KL, il eſt certain qu’ils ſeront en <lb/>équilibre, puiſque la ligne KG qui eſt un côté commun aux trian- <pb o="42" file="0150" n="153" rhead="LA SCIENCE DES INGENIEURS,"/> gles qui apartiennent aux vouſſoirs P & </s> <s xml:id="echoid-s2949" xml:space="preserve">Q, exprime en même tems <lb/>la force avec laquelle le vouſſoir P pouſſe le vouſſoir Q, & </s> <s xml:id="echoid-s2950" xml:space="preserve">celle <lb/>avec laquelle le premier eſt repouſſé par le ſecond; </s> <s xml:id="echoid-s2951" xml:space="preserve">de même ſi la <lb/>péſanteur du vouſſoir R eſt exprimée par LM, il ſera auſſi en équi-<lb/>libre avec le vouſſoir Q, le ſuperieur pouſſant l’inferieur avec la <lb/>même force dont il eſt repouſſé, puiſque cette force eſt exprimée <lb/>de part & </s> <s xml:id="echoid-s2952" xml:space="preserve">d’autre par la ligne GL qui eſt auſſi un côté commun aux <lb/>triangles qui apartiennent aux vouſſoirs Q & </s> <s xml:id="echoid-s2953" xml:space="preserve">R. </s> <s xml:id="echoid-s2954" xml:space="preserve">Enfin ſi la péſan-<lb/>teur du vouſſoir S eſt exprimée par MN, l’on verra par un ſembla-<lb/>ble raiſonnement qu’il ſera en équilibre avec le vouſſoir P, puiſ-<lb/>que ces deux vouſſoirs agiront l’un ſur l’autre avec la même force <lb/>GM: </s> <s xml:id="echoid-s2955" xml:space="preserve">à légard du vouſſoir T qui répond au pié-droit, ſa péſanteur <lb/>ne peut pas être déterminée, les lignes BO & </s> <s xml:id="echoid-s2956" xml:space="preserve">GC étant paralelles ne <lb/>ſe rencontreront jamais, ce qui montre que ce vouſſoir doit être <lb/>d’une péſanteur infinie pour réſiſter à l’effort de tous les autres dans <lb/>le cas où il pourroit gliſſer ſur un plan infiniment poli; </s> <s xml:id="echoid-s2957" xml:space="preserve">mais com-<lb/>me dans la pratique il n’eſt pas queſtion de ces ſortes de plans & </s> <s xml:id="echoid-s2958" xml:space="preserve"><lb/>qu’au contraire il ſe rencontre toûjours beaucoup de frotement, <lb/>il ſuffit de donner à ce vouſſoir le plus de péſanteur qu’il eſt poſ-<lb/>ſible.</s> <s xml:id="echoid-s2959" xml:space="preserve"/> </p> <div xml:id="echoid-div211" type="float" level="3" n="2"> <note position="right" xlink:label="note-0149-02" xlink:href="note-0149-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>6. <lb/><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s2960" xml:space="preserve">L’on remarquera que les differentes péſanteurs des vouſſoirs <lb/>peuvent être exprimées par la difference des tangentes des angles <lb/>que font les joints en commençant au milieu de la clef, puiſque <lb/>les lignes KL, LM, MN, qui expriment la péſanteur des vouſſoirs <lb/>P, Q, R, S, marquent la difference des tangentes des angles BGK, <lb/>BGL, BGM, & </s> <s xml:id="echoid-s2961" xml:space="preserve">BGN. </s> <s xml:id="echoid-s2962" xml:space="preserve">Or comme on a la valeur de tous ces angles, <lb/>par la diviſion qu’on a faite du demi cercle, il s’enſuit qu’ayant leur <lb/>tangentes dans les Tables des Sinus, ſi l’on en prend les differences, <lb/>l’on aura des nombres qui exprimeront les raports de la péſanteur <lb/>des vouſſoirs; </s> <s xml:id="echoid-s2963" xml:space="preserve">ainſi connoiſſant la péſanteur de la clef, on pourra <lb/>(par la regle de proportion) connoître celle de chaque vouſſoir, <lb/>afin de voir combien il faudra les faire plus longs les uns que les <lb/>autres; </s> <s xml:id="echoid-s2964" xml:space="preserve">c’eſt-à-dire, combien il faudra leur donner plus de queuë <lb/>pour qu’ils faſſent à peu-près le même effort. </s> <s xml:id="echoid-s2965" xml:space="preserve">Je dis à peu-près; </s> <s xml:id="echoid-s2966" xml:space="preserve">car <lb/>comme on employe ordinairement du mortier pour les entretenir, <lb/>il n’eſt pas neceſſaire d’obſerver une proportion bien exacte dans le <lb/>raport de leur péſanteur, il ſuffit ſeulement d’y avoir égard quand <lb/>on veut faire des édifices ſolides.</s> <s xml:id="echoid-s2967" xml:space="preserve"/> </p> <pb o="43" file="0151" n="154" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div213" type="section" level="2" n="46"> <head xml:id="echoid-head164" xml:space="preserve">PROPOSITION CINQUIE’ME</head> <head xml:id="echoid-head165" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s2968" xml:space="preserve">Trouver quelle eſt la courbe qu’il conviendroit de donner <lb/>à une Voûte, pour que tous les vouſſoirs, étant égaux en pé-<lb/>ſanteur, ſoient en équilibre.</s> <s xml:id="echoid-s2969" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2970" xml:space="preserve">40. </s> <s xml:id="echoid-s2971" xml:space="preserve">Si l’on tire ſur un plan vertical une ligne AB paralelle à l’hori-<lb/> <anchor type="note" xlink:label="note-0151-01a" xlink:href="note-0151-01"/> ſon, & </s> <s xml:id="echoid-s2972" xml:space="preserve">qu’à deux points C & </s> <s xml:id="echoid-s2973" xml:space="preserve">D, pris dans cette ligne, l’on attache <lb/>les extrêmités d’une chaine compoſée de petits couplets & </s> <s xml:id="echoid-s2974" xml:space="preserve">qu’on <lb/>leur laiſſe la liberté de prendre la ſituation qui leur convient, je dis <lb/>qu’ils compoſeront tous enſemble une courbe CFD, dont la figure <lb/>repreſente celle qu’il faudroit donner à une Voûte, pour que tous <lb/>les vouſſoirs ſoient en équilibre quoiqu’égaux en péſanteur.</s> <s xml:id="echoid-s2975" xml:space="preserve"/> </p> <div xml:id="echoid-div213" type="float" level="3" n="1"> <note position="right" xlink:label="note-0151-01" xlink:href="note-0151-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <p> <s xml:id="echoid-s2976" xml:space="preserve">Si l’on diviſe la ligne CD en deux parties égales au point E, & </s> <s xml:id="echoid-s2977" xml:space="preserve"><lb/>qu’on abaiſſe la perpendiculaire EF, il eſt conſtant qu’elle ira ren-<lb/>contrer le point F qui ſera le plus bas de la courbe; </s> <s xml:id="echoid-s2978" xml:space="preserve">car, à cauſe <lb/>de la flexibilité de la chaine & </s> <s xml:id="echoid-s2979" xml:space="preserve">l’uniformité qu’on ſupoſe dans les <lb/>couplets, la partie CF ſera égale à la partie DF, elles auront tou-<lb/>tes deux la même figure, & </s> <s xml:id="echoid-s2980" xml:space="preserve">tous les points pris dans la longueur <lb/>CF & </s> <s xml:id="echoid-s2981" xml:space="preserve">DF, à une égale diſtance des extremités C & </s> <s xml:id="echoid-s2982" xml:space="preserve">D, ſe trouveront <lb/>également ſitués par raport à la perpendiculaire EF, par conſéquent <lb/>cette chaine forme une courbe réguliere, qui a pour axe EF. </s> <s xml:id="echoid-s2983" xml:space="preserve">Or <lb/>tous les couplets qui compoſent cette chaine étant ſupoſés égaux <lb/>en grandeur & </s> <s xml:id="echoid-s2984" xml:space="preserve">en péſanteur, ſe maintiendront en équilibre entr’eux, <lb/>& </s> <s xml:id="echoid-s2985" xml:space="preserve">tendront chacun en particulier au centre de la terre par des lignes <lb/>deldirections, qui étant tirées de leur centre de gravité peuvent être <lb/>regardées comme perpendiculaires à l’horiſon: </s> <s xml:id="echoid-s2986" xml:space="preserve">& </s> <s xml:id="echoid-s2987" xml:space="preserve">ſi l’on attribuë à <lb/>chacun de ces couplets une péſanteur égale, mais incomparablement <lb/>au-deſſus de celle qu’ils ont naturellement, ils ſe ſoûtiendront toû-<lb/>jours dans le même état où ils étoient auparavant, n’y ayant point <lb/>de raiſon pour quel’un détourne lautre de la direction vers laquelle <lb/>ſa péſanteur le faiſoit tendre; </s> <s xml:id="echoid-s2988" xml:space="preserve">mais ſil’on faiſoit enſorte que les cou-<lb/>plets ſe trouvaſſent tellement unis les uns aux autres qu’ils ne com-<lb/>poſaſſent qu’un ſeul corps incapable d’aucune flexibilité, il ne leur <lb/>arriveroit rien de particulier, ſinon d’être obligé de garder la ſitua-<lb/>tion où ils étoient les uns par raport aux autres, de quelque ſens <lb/>qu’on veuille mettre la chaine, & </s> <s xml:id="echoid-s2989" xml:space="preserve">tant qu’elle ſera attachée aux <pb o="44" file="0152" n="155" rhead="LA SCIENCE DES INGENIEURS,"/> points C & </s> <s xml:id="echoid-s2990" xml:space="preserve">D, il lui ſera indifferent que tous les couplets ſoient <lb/>unis ou non, qu’on augmente leur péſanteur, ou qu’on la laiſſe <lb/>comme elle étoit en premier lieu: </s> <s xml:id="echoid-s2991" xml:space="preserve">on pourroit même ſuſpendre des <lb/>poids égaux au bas de chacun, ſans que cela cauſât aucun change-<lb/>ment à la courbe CFD.</s> <s xml:id="echoid-s2992" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s2993" xml:space="preserve">Prevenu de cela, on ſçait qu’on ne dérange rien dans l’équilibre <lb/>des puiſſances en changeant ſeulement leur direction en ſens con-<lb/>traire: </s> <s xml:id="echoid-s2994" xml:space="preserve">ainſi dans la ſupoſition que tous les couplets ſont unis à ne <lb/>pouvoir ſe déranger de la figure curviligne qu’ils compoſent tous <lb/>enſemble, ſi l’on fait tourner la chaine CFD ſur la ligne CD comme <lb/> <anchor type="note" xlink:label="note-0152-01a" xlink:href="note-0152-01"/> ſur un axe pour prendre la ſituation opoſée, mais toûjours verti-<lb/>cale CFD, tous les couplets, gardant entr’euxla même ſituation qu’ils <lb/>avoient auparavant, tendront au centre de la terre ſelon les mêmes <lb/>lignes de direction; </s> <s xml:id="echoid-s2995" xml:space="preserve">& </s> <s xml:id="echoid-s2996" xml:space="preserve">ſoit qu’on augmente leur péſanteur ou non, <lb/>pourvû que cette augmentation ſoit la même, ils ſe maintiendront <lb/>toûjours en équilibre, & </s> <s xml:id="echoid-s2997" xml:space="preserve">ils ne feront pas plus d’effort pour tomber <lb/>que s’ils n’étoient point entretenus par quelque cauſe qui les em-<lb/>pêche de ſe déranger.</s> <s xml:id="echoid-s2998" xml:space="preserve"/> </p> <div xml:id="echoid-div214" type="float" level="3" n="2"> <note position="left" xlink:label="note-0152-01" xlink:href="note-0152-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> <p> <s xml:id="echoid-s2999" xml:space="preserve">Supoſant preſentement que la courbe CFD repreſente l’intradoſe <lb/>d’une Voûte ABC, qui ſoit par-tout d’une égale épaiſſeur, & </s> <s xml:id="echoid-s3000" xml:space="preserve">qu’à <lb/>la place des couplets on imagine des Vouſſoirs fort petits qui ayent <lb/>la même péſanteur & </s> <s xml:id="echoid-s3001" xml:space="preserve">dont les lignes de directions tirées de leur <lb/>centre de gravité ſeront les mêmes que celles des couplets, ces <lb/> <anchor type="note" xlink:label="note-0152-02a" xlink:href="note-0152-02"/> vouſſoirs demeureront en équilibre ainſique l’étoient ces couplets, <lb/>deſorte que s’ils ſont bien unis les uns contre les autres par un ci-<lb/>ment qui les réduiſe tous à ne faire qu’un ſeul corps, ils compo-<lb/>ſeront enſemble la Voûte ABC, dont toutes les parties ſeront en <lb/>équilibre.</s> <s xml:id="echoid-s3002" xml:space="preserve"/> </p> <div xml:id="echoid-div215" type="float" level="3" n="3"> <note position="left" xlink:label="note-0152-02" xlink:href="note-0152-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 5.</note> </div> <p> <s xml:id="echoid-s3003" xml:space="preserve">Si l’on vouloit faire uſage de cette courbe, je crois qu’on ſeroit <lb/>obligé de raprocher ſes deux entrêmités G & </s> <s xml:id="echoid-s3004" xml:space="preserve">H, afin qu’elles ſoient <lb/>diſpoſées comme EA & </s> <s xml:id="echoid-s3005" xml:space="preserve">FC, & </s> <s xml:id="echoid-s3006" xml:space="preserve">non pas comme EG & </s> <s xml:id="echoid-s3007" xml:space="preserve">FH, qui ne <lb/>conviendroit pas dans l’execution, à cauſe que la naiſſance de la <lb/>Voûte feroit un Farret avec le pié-droit, ce qui choqueroit la vûë, <lb/>il eſt bon de profiter de ce que la théorie peut enſeigner; </s> <s xml:id="echoid-s3008" xml:space="preserve">mais <lb/>quand il s’agit de la pratique, on peut ſans ſcrupule ne le pas <lb/>ſuivre exactement pour raporter les choſes à l’uſage. </s> <s xml:id="echoid-s3009" xml:space="preserve">On trouvera <lb/>dans le ſecond tome de l’Analiſe du R. </s> <s xml:id="echoid-s3010" xml:space="preserve">P. </s> <s xml:id="echoid-s3011" xml:space="preserve">Reyneau l’équation de <lb/>la chainette & </s> <s xml:id="echoid-s3012" xml:space="preserve">la maniere de la tracer, c’eſt pourquoi je n’en parle <lb/>point ici.</s> <s xml:id="echoid-s3013" xml:space="preserve"/> </p> <pb o="45" file="0153" n="156" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div217" type="section" level="2" n="47"> <head xml:id="echoid-head166" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s3014" xml:space="preserve">Si l’on vouloit conſtruire une Voûte naturelle dont la largeur & </s> <s xml:id="echoid-s3015" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0153-01a" xlink:href="note-0153-01"/> la hauteur fuſſent données, il faut ſur une ſurface verticale tracer <lb/>une ligne CD égale à la largeur de la Voûte, abaiſſer du milieu de <lb/>cette ligne une perpendiculaire EF, égale à la hauteur qu’on veut <lb/>lui donner, enſuite attacher l’extrêmité d’une chaine au point C, <lb/>& </s> <s xml:id="echoid-s3016" xml:space="preserve">porter l’autre extrêmité vers D, de maniere qu’en augmentant <lb/>ou diminuant la chaine ſon propre poids la faſſe paſſer par le point <lb/>F, lorſqu’elle ſera arrêtée aux endroits C & </s> <s xml:id="echoid-s3017" xml:space="preserve">D; </s> <s xml:id="echoid-s3018" xml:space="preserve">après cela on pourra <lb/>avec un crayon que l’on conduira tout du long de la chaine (ſans <lb/>pourtant la faire vaciller) tracer une courbe, & </s> <s xml:id="echoid-s3019" xml:space="preserve">là-deſſus on pourra <lb/>établir la figure du faux ceintre de la Voûte, la coupe des vouſſoirs, <lb/>& </s> <s xml:id="echoid-s3020" xml:space="preserve">le reſte.</s> <s xml:id="echoid-s3021" xml:space="preserve"/> </p> <div xml:id="echoid-div217" type="float" level="3" n="1"> <note position="right" xlink:label="note-0153-01" xlink:href="note-0153-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <p> <s xml:id="echoid-s3022" xml:space="preserve">Je crois que ceux qui ſont dans l’uſage de faire conſtruire des <lb/>Voûtes, ſans y prendre garde de ſi près, ne feront pas grand cas des <lb/>deux propoſitions précédentes, auſſi ne les ai-je raportées que pour <lb/>les curieux qui voyent toujours avec plaiſir ce qui peut avoir ra-<lb/>port à leur métier; </s> <s xml:id="echoid-s3023" xml:space="preserve">cen’eſt pas qu’on n’en puiſſe faire uſage, puiſque <lb/>la premiere nous aprend que pour rendre des Voûtes ſolides, il eſt <lb/>bon d’en fortifier les reins le plus qu’il ſera poſſible, & </s> <s xml:id="echoid-s3024" xml:space="preserve">particuliere-<lb/>ment vers les piés-droits, afin de donner, pour ainſi dire, un contre-<lb/>poids à la pouſſée des vouſſoirs ſuperieurs.</s> <s xml:id="echoid-s3025" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div219" type="section" level="2" n="48"> <head xml:id="echoid-head167" xml:space="preserve">PROPOSITION SIXIE’ME.</head> <head xml:id="echoid-head168" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s3026" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux Culées des <lb/>Ponts de Maçonnerie.</s> <s xml:id="echoid-s3027" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3028" xml:space="preserve">41. </s> <s xml:id="echoid-s3029" xml:space="preserve">La maniere de régler l’épaiſſeur des Culées des Ponts eſt <lb/>un Probléme qui apartient à ce Livre-ci; </s> <s xml:id="echoid-s3030" xml:space="preserve">car les Ponts ſont com-<lb/>poſés d’Arches, & </s> <s xml:id="echoid-s3031" xml:space="preserve">les Arches ne ſont autre choſe que des Voûtes: <lb/></s> <s xml:id="echoid-s3032" xml:space="preserve">auſſi ſa ſolution dépent-elle des régles que nous venons d’en-<lb/>ſeigner, ou pour mieux dire elle n’en eſt qu’une répétition accom-<lb/>pagnée de quelque circonſtance particuliere aux Ponts de Maçon-<lb/>nerie.</s> <s xml:id="echoid-s3033" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3034" xml:space="preserve">On ſupoſe qu’il eſt queſtion d’un Pont compoſé d’une ſeule Arche <lb/>en plain ceintre comme dans la figure 6. </s> <s xml:id="echoid-s3035" xml:space="preserve">dont l’épaiſſeur GD eſt <pb o="46" file="0154" n="157" rhead="LA SCIENCE DES INGENIEURS,"/> déterminée de même que le diamêtre BI & </s> <s xml:id="echoid-s3036" xml:space="preserve">la hauteur BS depuis <lb/>la derniere retraite des fondemens juſqu’à la naiſſance de l’Arche, <lb/>& </s> <s xml:id="echoid-s3037" xml:space="preserve">qu’il s’agit de ſçavoir l’epaiſſeur PS ou MQ, qu’il faut donner <lb/>à la Culée MS pour qu’elle ſoit en équilibre avec la pouſſée qu’elle <lb/>doit ſoutenir. </s> <s xml:id="echoid-s3038" xml:space="preserve">Cela poſé, on ſaura queles Culées d’un Pont peuvent <lb/>être conſtruites de deux manieres: </s> <s xml:id="echoid-s3039" xml:space="preserve">la premiere eſt de faire un corps <lb/>de Maçonnerie comme SZ dans la 9. </s> <s xml:id="echoid-s3040" xml:space="preserve">figure, dont la hauteur ZP ou <lb/>BS ne ſurpaſſe point la naiſſance de l’Arche: </s> <s xml:id="echoid-s3041" xml:space="preserve">la ſeconde eſt d’élever <lb/> <anchor type="note" xlink:label="note-0154-01a" xlink:href="note-0154-01"/> la Culée juſques vers le milieu des reins del’Arche, afin de les ren-<lb/>dre capables de mieux ſoûtenir l’effort de la partie ſuperieure, <lb/>comme dans la figure 6. </s> <s xml:id="echoid-s3042" xml:space="preserve">à laquelle nous nous attacherons unique-<lb/>ment comme la plus conforme à l’uſage.</s> <s xml:id="echoid-s3043" xml:space="preserve"/> </p> <div xml:id="echoid-div219" type="float" level="3" n="1"> <note position="left" xlink:label="note-0154-01" xlink:href="note-0154-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 6. <lb/>& 9.</note> </div> <p> <s xml:id="echoid-s3044" xml:space="preserve">Ayant diviſé le quart de cercle BD en deux également au point C, <lb/>on tirera le rayon AF: </s> <s xml:id="echoid-s3045" xml:space="preserve">on diviſera auſſi la ligne FC en deux égale-<lb/>ment au point L par lequel on menera MK paralelle au diamêtre <lb/>BI qui determinera la hauteur de la Culée, on prolongera la ligne <lb/>SB juſqu’au point Q de la circonférence, & </s> <s xml:id="echoid-s3046" xml:space="preserve">on tirera le rayon AQ, <lb/>& </s> <s xml:id="echoid-s3047" xml:space="preserve">les autres lignes LO, LV, & </s> <s xml:id="echoid-s3048" xml:space="preserve">OP, comme à l’ordinaire.</s> <s xml:id="echoid-s3049" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3050" xml:space="preserve">Pour réduire en équation la pouſſée de l’Arche & </s> <s xml:id="echoid-s3051" xml:space="preserve">la réſiſtance <lb/>des Culées, nous nommerons LK ou KA, a; </s> <s xml:id="echoid-s3052" xml:space="preserve">BV, c; </s> <s xml:id="echoid-s3053" xml:space="preserve">MP, d; </s> <s xml:id="echoid-s3054" xml:space="preserve">Sr, <lb/>g; </s> <s xml:id="echoid-s3055" xml:space="preserve">PS, y; </s> <s xml:id="echoid-s3056" xml:space="preserve">la ſuperficie CFGD, nn; </s> <s xml:id="echoid-s3057" xml:space="preserve">& </s> <s xml:id="echoid-s3058" xml:space="preserve">la partie BQFC, hh: </s> <s xml:id="echoid-s3059" xml:space="preserve">ainſi <lb/>MN ou ML ſera c + y; </s> <s xml:id="echoid-s3060" xml:space="preserve">& </s> <s xml:id="echoid-s3061" xml:space="preserve">NP ſera d - c - y; </s> <s xml:id="echoid-s3062" xml:space="preserve">& </s> <s xml:id="echoid-s3063" xml:space="preserve">ſi l’on ſupoſe <lb/>d - c = f, NP ſera f - y.</s> <s xml:id="echoid-s3064" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3065" xml:space="preserve">L’on ſait par l’Article 14. </s> <s xml:id="echoid-s3066" xml:space="preserve">que multipliant la ſuperficie CFGD <lb/>(nn) par l’hipotenuſe NP (f - y) du triangle rectangle NOP, lorſ-<lb/>qu’il s’agit d’une Voûte ou d’une Arche en plein ceintre, que le pro-<lb/>duit donne une expreſſion égale à la puiſſance qui ſoutiendroit la <lb/>pouſſée de la partie CFGD, ainſi cette pouſſée ſera nnf - nny, <lb/>qu’il faut mettre en équilibre avec la réſiſtance du pié-droit PMQS, <lb/>joint à la partie BQFS; </s> <s xml:id="echoid-s3067" xml:space="preserve">c’eſt-à-dire avec dy & </s> <s xml:id="echoid-s3068" xml:space="preserve">hh, multipliés par le <lb/>bras de lévier PT ({y/2}) & </s> <s xml:id="echoid-s3069" xml:space="preserve">Pr (y + g) dont les extrêmités T & </s> <s xml:id="echoid-s3070" xml:space="preserve">r <lb/>répondent aux lignes de directions tirées de leur centre de gravité; <lb/></s> <s xml:id="echoid-s3071" xml:space="preserve">c’eſt-à-dire, avec {dyy/2} & </s> <s xml:id="echoid-s3072" xml:space="preserve">hhy + hhg, qui donnent cette équation <lb/>fnn - nny = {dyy/2} + hhy + hhg, d’où faiſant paſſer dans le même <lb/>membre les termes où ſe trouvent l’inconnu, & </s> <s xml:id="echoid-s3073" xml:space="preserve">dans l’autre ceux <lb/>où l’inconnu ne ſe trouve point, l’on aura après avoir diviſé par d, <lb/>{fnn + ghh/d} = {yy/2} + {nny + hhy/d}, & </s> <s xml:id="echoid-s3074" xml:space="preserve">ſi l’on ſupoſe {nn + hh/d} = p, &</s> <s xml:id="echoid-s3075" xml:space="preserve"> <pb o="47" file="0155" n="158" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> qu’on mette p à la place de ſa valeur multipliant toute l’équation <lb/>par 2, on pourra du ſecond membre en faire un quarré parfait en <lb/>ajoûtant pp de part & </s> <s xml:id="echoid-s3076" xml:space="preserve">d’autre afin d’avoir {2fnn + 2ghh/d} + pp = yy <lb/>+ 2py + pp, dont extrayant la racine & </s> <s xml:id="echoid-s3077" xml:space="preserve">dégageant l’inconnu, l’on <lb/>aura enfin √2fnn - 2ghh + pp\x{0020} - p = y, qui donne ce que l’on <lb/>cherche.</s> <s xml:id="echoid-s3078" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div221" type="section" level="2" n="49"> <head xml:id="echoid-head169" xml:space="preserve">APLICATION.</head> <p> <s xml:id="echoid-s3079" xml:space="preserve">Pour avoir la valeur de l’inconnu, nous ſupoſerons le diamêtre <lb/>BI de 72 pieds, l’épaiſſeur DG de 6, & </s> <s xml:id="echoid-s3080" xml:space="preserve">la hauteur BS de 12, ainſi <lb/>la ligne AL ſera de 15, & </s> <s xml:id="echoid-s3081" xml:space="preserve">l’on trouvera que BV (c) eſt de 8 pieds <lb/>5 pouces, & </s> <s xml:id="echoid-s3082" xml:space="preserve">LV de 27 pieds 7 pouces, par conſéquent MP (d) ſera <lb/>de 29 pieds 7 pouces: </s> <s xml:id="echoid-s3083" xml:space="preserve">& </s> <s xml:id="echoid-s3084" xml:space="preserve">comme nous avons ſupoſé d - c = f, <lb/>f ſera donc de 31 pieds 2 pouces; </s> <s xml:id="echoid-s3085" xml:space="preserve">on trouvera auſſi que la partie <lb/>CFGD (nn) eſt de 184 pieds quarrés.</s> <s xml:id="echoid-s3086" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3087" xml:space="preserve">Comme nous avons auſſi beſoin de la figure BQFC, remarquez <lb/>que la ligne BQ eſt moyenne proportionnelle entre les parties EB <lb/>& </s> <s xml:id="echoid-s3088" xml:space="preserve">BH, du diamêtre EH; </s> <s xml:id="echoid-s3089" xml:space="preserve">ainſi multipliantleur valeur, c’eſt-à-dire, <lb/>6 pieds par 78, on trouvera en extrayant la racine quarrée du pro-<lb/>duit 21 pieds 6 pouces 6 lignes, pour la perpendiculaire BQ, par <lb/>le moyen de laquelle on aura la ſuperficie du triangle ABQ, qui <lb/>eſt de 389 pieds 3 pouces; </s> <s xml:id="echoid-s3090" xml:space="preserve">or cherchant auſſi la valeur du ſecteur <lb/>EAQ qui eſt de 477 pieds 3 pouces, on en retranchera celle du <lb/>triangle ABQ, la difference ſera 88 pieds, pour le ſecment EBQ, <lb/>qui étant auſſi retranché de 184 pieds, valeur de EFCB, la differen-<lb/>ce ſera 96 pieds pour la partie BQFC, par conſéquent la valeur de hh. <lb/></s> <s xml:id="echoid-s3091" xml:space="preserve">D’un autre côté le centre de gravité de cette partie étant au point X, <lb/>l’on verra que la perpendiculaire Xr, vient tomber environ à 2 <lb/>pieds 9 pouces du point S, enfin comme nous avons ſupoſé {nn + hh/d} <lb/>= p, l’on trouvera que p vaut à peu-près 7 pieds 1 pouce, ainſi <lb/>comme toutes les lettres du premier membre de l’équation <lb/>√{2fnn/d} - {2ghh/d} + pp\x{0020} - p = y, viennent d’être déterminées en <lb/>nombre, ſi l’on fait les mêmes opérations qui s’y trouvent indiquées, <lb/>l’on trouvera que y, ou ſi l’on veut l’épaiſſeur PS de la Culée, doit <lb/>être de 11 pieds pour ſoûtenir en équilibre la pouſſée de la partie de <lb/>l’Arche qui lui répond.</s> <s xml:id="echoid-s3092" xml:space="preserve"/> </p> <pb o="48" file="0156" n="159" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div222" type="section" level="2" n="50"> <head xml:id="echoid-head170" style="it" xml:space="preserve">Remarque premiere.</head> <p> <s xml:id="echoid-s3093" xml:space="preserve">42. </s> <s xml:id="echoid-s3094" xml:space="preserve">On pourra ſe diſpenſer dans la pratique d’avoir égard à la <lb/>partie BQF, qui rend ce Probléme aſſés compoſé, & </s> <s xml:id="echoid-s3095" xml:space="preserve">n’avoir atten-<lb/>tion qu’au vouſſoir CFGD & </s> <s xml:id="echoid-s3096" xml:space="preserve">à la Culée MS, alors l’équation ſera <lb/>beaucoup plus ſimple, puiſque, dans l’état d’équilibre, on aura fnn <lb/>- nny = {dyy/2}, qui étant réduit donne après avoir dégagé l’inconnu <lb/>√{2fnn/d} + {n+/dd}\x{0020} - {nn/d} = y, dont le calcul numerique n’eſt pas long, <lb/>puiſque, pour avoir la valeur de toutes les lettres, on n’aura ſeule-<lb/>ment qu’à chercher celle des lignes LV, VB, & </s> <s xml:id="echoid-s3097" xml:space="preserve">la ſuperficie de la <lb/>partie CFGD; </s> <s xml:id="echoid-s3098" xml:space="preserve">il eſt vrai que l’épaiſſeur de la Culée ſera un peu plus <lb/>forte qu’elle ne devroit être pour un parfait équilibre, puiſqu’ayant <lb/>calculé cette derniere équation, j’ai trouvé qu’elle donnoit 13 pieds <lb/>2 pouces 8 lignes, au lieu de 11 pieds, pour la valeur de y; </s> <s xml:id="echoid-s3099" xml:space="preserve">mais <lb/>comme ce n’eſt pas l’équilibre que l’on cherche, puiſqu’il faut toû-<lb/>jours mettre la puiſſance réſiſtante au-deſſus de l’agiſſante, il vaut <lb/>beaucoup mieux, comme je l’ai déja dit, faire abſtraction de la <lb/>partie BQFC, pour trouver plus facilement l’épaiſſeur quel’on de-<lb/>mande & </s> <s xml:id="echoid-s3100" xml:space="preserve">être plus aſſuré de la ſolidité de l’ouvrage.</s> <s xml:id="echoid-s3101" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div223" type="section" level="2" n="51"> <head xml:id="echoid-head171" style="it" xml:space="preserve">Remarque ſeconde.</head> <p> <s xml:id="echoid-s3102" xml:space="preserve">43. </s> <s xml:id="echoid-s3103" xml:space="preserve">En cherchant l’épaiſſeur qu’il falloit donner aux Culées, <lb/>nous n’avons point eu égard au poids dont l’Arche pouvoit être <lb/>chargée au-delà du ſien propre, de la part des materiaux qui doi-<lb/>vent compoſer la Chauſſée & </s> <s xml:id="echoid-s3104" xml:space="preserve">des Voitures qui paſſeront deſſus, <lb/>parce que je laiſſe à la diſcretion de ceux qui ſont chargés de l’exe-<lb/>cution de ces ſortes d’ouvrages, d’en augmenter l’épaiſſeur autant <lb/>qu’ils le jugeront à propos: </s> <s xml:id="echoid-s3105" xml:space="preserve">je crois que ſi on l’augmentoit d’un <lb/>ſixiéme de ce que donne le calcul, que c’eſt la plus grande aug-<lb/>mentation qu’on puiſſe faire; </s> <s xml:id="echoid-s3106" xml:space="preserve">c’eſt-à-dire, qu’au lieu de 13 pieds 2 <lb/>pouces 8 lignes, il faudroit lui donner environ 15 pieds & </s> <s xml:id="echoid-s3107" xml:space="preserve">demi.</s> <s xml:id="echoid-s3108" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div224" type="section" level="2" n="52"> <head xml:id="echoid-head172" style="it" xml:space="preserve">Remarque troiſiéme.</head> <p> <s xml:id="echoid-s3109" xml:space="preserve">44. </s> <s xml:id="echoid-s3110" xml:space="preserve">Nous avons ſupoſé un Pont d’une ſeule Arche, parce que <lb/>quand il y en auroit davantage, ce ne ſeroit jamais que la pouſſée <lb/>de la premiere & </s> <s xml:id="echoid-s3111" xml:space="preserve">de la derniere que l’on conſidéreroit pour leur <pb o="49" file="0157" n="160" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> opoſer des Culées, puiſque les autres qui ſont compriſes entre cel-<lb/>les-ci ſe ſoutiennent mutuellement en équilibre ſur les piles qui les <lb/>portent, à moins que ces Arches ne ſoient beaucoup plus grandes <lb/>que celles des extrêmités du Pont; </s> <s xml:id="echoid-s3112" xml:space="preserve">car alors il pourroit arriver que <lb/>la pouſſée des petites Arches ſeroit augmentée par celle des autres <lb/>plus grande.</s> <s xml:id="echoid-s3113" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div225" type="section" level="2" n="53"> <head xml:id="echoid-head173" style="it" xml:space="preserve">Remarque quatriéme.</head> <p> <s xml:id="echoid-s3114" xml:space="preserve">45. </s> <s xml:id="echoid-s3115" xml:space="preserve">Quand on fait des Arches d’une grandeur extraordinaire, <lb/>& </s> <s xml:id="echoid-s3116" xml:space="preserve">qu’on eſt obligé de donner une épaiſſeur conſiderable aux Culées, <lb/>on peut, pour diminuer une trop grande quantité de Maçonnerie, <lb/>donner beaucoup de talud aux extrêmités de la Culée, comme un <lb/>tiers on un quart de la hauteur, ou y faire des contreforts comme <lb/>on l’a enſeigné dans les Articles 17. </s> <s xml:id="echoid-s3117" xml:space="preserve">& </s> <s xml:id="echoid-s3118" xml:space="preserve">20.</s> <s xml:id="echoid-s3119" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div226" type="section" level="2" n="54"> <head xml:id="echoid-head174" style="it" xml:space="preserve">Remarque cinquiéme.</head> <p> <s xml:id="echoid-s3120" xml:space="preserve">46. </s> <s xml:id="echoid-s3121" xml:space="preserve">Si au lieu d’une Arche en plain ceintre on en avoit une ſurbaiſ-<lb/>ſée, on trouvera l’épaiſſeur qu’il faut donner aux Culées en ſuivant <lb/>ce qui a été enſeigné dans les Articles 30. </s> <s xml:id="echoid-s3122" xml:space="preserve">& </s> <s xml:id="echoid-s3123" xml:space="preserve">31. </s> <s xml:id="echoid-s3124" xml:space="preserve">puiſque ſi l’on en <lb/>excepte quelque particularité qu’il y a ici, & </s> <s xml:id="echoid-s3125" xml:space="preserve">qui ne ſe trouve pas <lb/>dans les Voûtes, tout le reſte eſt la même choſe.</s> <s xml:id="echoid-s3126" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div227" type="section" level="2" n="55"> <head xml:id="echoid-head175" xml:space="preserve">PROPOSITION SEPTIE’ME.</head> <head xml:id="echoid-head176" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s3127" xml:space="preserve">Trouver quelle eſt la portée des Vouſſoirs, depuis leur in-<lb/>trados, juſqu’à leur extrados, & </s> <s xml:id="echoid-s3128" xml:space="preserve">quelle doit être la largeur <lb/>des piles pour toute ſorte de grandeur d’Arche.</s> <s xml:id="echoid-s3129" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3130" xml:space="preserve">47. </s> <s xml:id="echoid-s3131" xml:space="preserve">Danstous les Edifices où il eſt queſtion de Voûte, il doit regner <lb/>une certaine proportion dans les dimenſions de leur parties, d’où dé-<lb/>pend toute la ſolidité; </s> <s xml:id="echoid-s3132" xml:space="preserve">par exemple, nous venons de voir au ſujet des <lb/>Ponts, qu’il falloit qu’il y eût un raport d’égalité entre la réſiſtance des <lb/>Culées & </s> <s xml:id="echoid-s3133" xml:space="preserve">la pouſſée des Arches; </s> <s xml:id="echoid-s3134" xml:space="preserve">mais comme ces Arches peuvent être <lb/>de differente grandeur, il faut abſolument que leur épaiſſeur ſoit pro-<lb/>portionnée à leur ouverture, afin que celle qui auroit 12 ou 15 <lb/>toiſes réſiſte auſſi-bien au poids des materiaux & </s> <s xml:id="echoid-s3135" xml:space="preserve">des voitures dont <lb/>elle pourra être chargée, qu’une autre qui n’auroit que 12 ou 15 <pb o="50" file="0158" n="161" rhead="LA SCIENCE DES INGENIEURS,"/> pieds; </s> <s xml:id="echoid-s3136" xml:space="preserve">mais la ſolution de ce Probléme dépend plûtôt de l’intelligen-<lb/>ce de ceux qui font travailler, que de la Géometrie: </s> <s xml:id="echoid-s3137" xml:space="preserve">c’eſt pourquoi <lb/>il ſemble que le meilleur parti eſt de s’en raporter à l’experience; <lb/></s> <s xml:id="echoid-s3138" xml:space="preserve">c’eſt-à-dire d’examiner avec attention les anciens monumens de cette <lb/>eſpece, afin qu’ayant reconnu la qualité des pierres qu’on y a em-<lb/>ployé, la longueur des vouſſoirs à pluſieurs grandeurs d’Arches dif-<lb/>férentes, on ſoit en état de calculer une table qui puiſſe ſervir dans <lb/>tous les cas qu’on peut rencontrer. </s> <s xml:id="echoid-s3139" xml:space="preserve">C’eſt ce que Mr. </s> <s xml:id="echoid-s3140" xml:space="preserve">Gautier a fait: </s> <s xml:id="echoid-s3141" xml:space="preserve"><lb/>nul n’étoit plus capable que lui de remplir un pareil deſſein; </s> <s xml:id="echoid-s3142" xml:space="preserve">il a <lb/>vû & </s> <s xml:id="echoid-s3143" xml:space="preserve">fait la deſcription des plus beaux Ponts qui ont été bâtis en <lb/>France, tant par les anciens que par les modernes: </s> <s xml:id="echoid-s3144" xml:space="preserve">ainſi, il me <lb/>ſuffira de raporter la Table qu’il a calculée pour la portée des vouſ-<lb/>ſoirs; </s> <s xml:id="echoid-s3145" xml:space="preserve">on verra qu’il a eû égard aux pierres dures & </s> <s xml:id="echoid-s3146" xml:space="preserve">à celles qui ne <lb/>le ſeroient pas, afin qu’on ait recours à la colomne dont la pierre <lb/>auroit quelque raport avec celle qu’on veut employer. </s> <s xml:id="echoid-s3147" xml:space="preserve">Ceux, qui <lb/>n’ont pas une grande connoiſſance des travaux, ſeront peut-être <lb/>ſurpris de voir dans la colomne où l’on ſupoſe la pierre tendre des <lb/>vouſſoirs de 8 & </s> <s xml:id="echoid-s3148" xml:space="preserve">même de 9 pieds de longueur, par la difficulté <lb/>qu’il y auroit d’avoir des pierres d’un ſi grand apareil; </s> <s xml:id="echoid-s3149" xml:space="preserve">auſſi ne pré-<lb/>tend-on pas que ces vouſſoirs ſoient abſolument compoſés d’une <lb/>ſeule pierre, puiſque quand on n’en a pas d’aſſés grandes on les al-<lb/>longe pour faire ce qu’on apelle des vouſſoirs ſans fin. </s> <s xml:id="echoid-s3150" xml:space="preserve">C’eſt ainſi qu’on <lb/>en a uſé pour conſtruire le Pont Royal des Thuilleries à Paris.</s> <s xml:id="echoid-s3151" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3152" xml:space="preserve">La largeur, que l’on doit donner aux Piles des Ponts par raport à <lb/>l’ouverture des Arches, eſt encore une difficulté ſur laquelle les Ar-<lb/>chitectes ne s’accordent point, & </s> <s xml:id="echoid-s3153" xml:space="preserve">que la Geometrie paroît ne pouvoir <lb/>entreprendre, puiſqu’elle dépend abſolument de la conſiſtance de la <lb/>pierre: </s> <s xml:id="echoid-s3154" xml:space="preserve">car comme il s’agit de rendre les Piles aſſés fortes pour <lb/>ſoutenir le poids des Arches, & </s> <s xml:id="echoid-s3155" xml:space="preserve">tout ce qu’elles peuvent porter, il <lb/>n’y a pas de doute que la pile qui n’auroit qu’une mediocre largeur, <lb/>& </s> <s xml:id="echoid-s3156" xml:space="preserve">qui ſeroit conſtruite de bonne & </s> <s xml:id="echoid-s3157" xml:space="preserve">grande Pierre de Taille, ne ſou-<lb/>tienne plûtôt une Arche de 15 toiſes d’ouverture, qu’une autre <lb/>Pile qui auroit deux fois plus de largeur, mais qui n’auroit que le <lb/>parement de Pierre dure, & </s> <s xml:id="echoid-s3158" xml:space="preserve">le dedans rempli de mauvais moîlon, <lb/>n’en ſoûtiendroit une de huit toiſes. </s> <s xml:id="echoid-s3159" xml:space="preserve">Cependant, il eſt de conſéquen-<lb/>ce de ſe ſervir de bonne Pierre, pour n’être pas contraint de donner <lb/>une trop grande largeur aux Piles, parce que ſi le lit de la Rivierre <lb/>ſur laquelle on veut faire un Pont eſt reſſerré, il eſt à craindre que le <lb/>courant de l’eau, ſe trouvant gêné, ne renverſe le Pont dans le tems <lb/>des grandes inondations, comme cela arrive aſſés ſouvent. </s> <s xml:id="echoid-s3160" xml:space="preserve">Un autre <lb/>inconvenient encore des Piles trop larges; </s> <s xml:id="echoid-s3161" xml:space="preserve">c’eſt que leurs avant-becs <pb o="51" file="0159" n="162" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> preſentent de grandes faces qui donnent beaucoup de priſes aux <lb/>glaces quand la Riviere charie; </s> <s xml:id="echoid-s3162" xml:space="preserve">& </s> <s xml:id="echoid-s3163" xml:space="preserve">les chocs violens qui ſurviennent <lb/>alors peuvent mettre le Pont en danger, comme cela eſt arrivé au <lb/>Pont Marie à Paris. </s> <s xml:id="echoid-s3164" xml:space="preserve">Mais pour ſuivre une regle qui détermine la lar-<lb/>geur des Piles, je crois que celle qui convient mieux eſt de leur <lb/>donner la cinquiéme partie de la largeur des Arches; </s> <s xml:id="echoid-s3165" xml:space="preserve">c’eſt-à-dire, <lb/>par exemple, que ſi l’on a un Pont compoſé de cinq Arches, & </s> <s xml:id="echoid-s3166" xml:space="preserve">que <lb/>celle du milieu ait 60 pieds d’ouverture, les Piles qui la ſoutien-<lb/>dront doivent en avoir 12 de largeur; </s> <s xml:id="echoid-s3167" xml:space="preserve">que ſi les Arches collateral-<lb/>les ont chacune à droit & </s> <s xml:id="echoid-s3168" xml:space="preserve">à gauche 50 pieds d’ouverture, les Piles <lb/>qui leur répondront en auront 10. </s> <s xml:id="echoid-s3169" xml:space="preserve">Il ne faut pourtant pas ſuivre ſi <lb/>conſtamment cette proportion, qu’on ne s’en écarte quand il ſe <lb/>rencontrera quelque circonſtance qui pourroit obliger de donner <lb/>aux Piles plus ou moins de largeur, ſelon que la bonne ou mau-<lb/>vaiſe qualité des materiaux l’exigeroit.</s> <s xml:id="echoid-s3170" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3171" xml:space="preserve">Je crois qu’il eſt à propos de dire que les Arches des Ponts doi-<lb/>vent toûjours être en nombre impair, afin qu’il s’en trouve une <lb/>grande au milieu qui laiſſe un paſſage libre au courant de l’eau, & </s> <s xml:id="echoid-s3172" xml:space="preserve"><lb/>que cette Arche étant plus élevée facilite le paſſage des Bateaux <lb/>chargés.</s> <s xml:id="echoid-s3173" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3174" xml:space="preserve">Voilà ce que je m’étois propoſé de dire ici ſur les Ponts, pour <lb/>faire mention ſeulement de quelques régles generales qui avoient <lb/>raport aux Voûtes; </s> <s xml:id="echoid-s3175" xml:space="preserve">car, comme leur conſtruction demande des <lb/>connoiſſances bien au-delà de celles qu’il faut pour les Edifices or-<lb/>dinaires, nous reprendrons ce ſujet dans l’Architecture Ydrolique <lb/>afin de ſatisfaire ceux qui ont un interêt particulier de s’en inſtruire.</s> <s xml:id="echoid-s3176" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3177" xml:space="preserve">Voici la Table dont je viens de parler, où l’on obſervera que la <lb/>premiere & </s> <s xml:id="echoid-s3178" xml:space="preserve">la quatriéme colomne comprennent l’ouverture des <lb/>Arches, qui vont toûjours en augmentant ſelon la ſuite des nombres <lb/>naturels.</s> <s xml:id="echoid-s3179" xml:space="preserve"/> </p> <figure> <image file="0159-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0159-01"/> </figure> <pb o="52" file="0160" n="163" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div228" type="section" level="2" n="56"> <head xml:id="echoid-head177" xml:space="preserve">TABLE</head> <head xml:id="echoid-head178" style="it" xml:space="preserve">POVR CONNOISTRE LA PORTE’E DES VOVSSOIRS <lb/>depuis leur intrados à leur extrados pour toute ſorte de grandeur <lb/>d’Arche.</head> <note position="right" xml:space="preserve">Ou- \\ vertu \\ re des \\ Arches. ### Vouſſoirs de \\ Pierres dures. ### Vouſſoirs de \\ Pierres tendres. # Ouver- \\ ture des \\ Arches. ### Vouſſoirs de \\ Pierres dures. ### Vouſſoirs de \\ Pierres tendres. <lb/>pieds. # pieds. # pou. # lig. # pieds. # pou. # lig. # pieds. # pieds. # pou. # lig. # pieds. # pou. # lig. <lb/>1 # 1 # 0 # 6 # 1 # 6 # 0 # 28 # 2 # 2 # 0 # 2 # 11 # 6 <lb/>2 # 1 # 1 # 0 # 1 # 7 # 2 # 29 # 2 # 2 # 6 # 2 # 11 # 9 <lb/>3 # 1 # 1 # 6 # 1 # 8 # 4 # 30 # 2 # 3 # 0 # 3 # 0 # 0 <lb/>4 # 1 # 2 # 0 # 1 # 9 # 6 # 31 # 2 # 3 # 6 # 3 # 0 # 10 <lb/>5 # 1 # 2 # 6 # 1 # 10 # 8 # 32 # 2 # 4 # 0 # 3 # 1 # 8 <lb/>6 # 1 # 3 # 0 # 2 # 0 # 0 # 33 # 2 # 4 # 6 # 3 # 2 # 6 <lb/>7 # 1 # 3 # 6 # 2 # 0 # 8 # 34 # 2 # 5 # 0 # 3 # 3 # 0 <lb/>8 # 1 # 4 # 0 # 2 # 1 # 6 # 35 # 2 # 5 # 6 # 3 # 3 # 10 <lb/>9 # 1 # 4 # 6 # 2 # 2 # 3 # 36 # 2 # 6 # 0 # 3 # 4 # 0 <lb/>10 # 1 # 5 # 0 # 2 # 3 # 0 # 37 # 2 # 6 # 6 # 3 # 4 # 6 <lb/>11 # 1 # 5 # 6 # 2 # 4 # 0 # 38 # 2 # 7 # 0 # 3 # 5 # 0 <lb/>12 # 1 # 6 # 0 # 2 # 4 # 6 # 39 # 2 # 7 # 6 # 3 # 5 # 6 <lb/>13 # 1 # 6 # 6 # 2 # 5 # 0 # 40 # 2 # 8 # 0 # 3 # 8 # 0 <lb/>14 # 1 # 7 # 0 # 2 # 6 # 0 # 41 # 2 # 8 # 10 # 3 # 8 # 10 <lb/>15 # 1 # 7 # 6 # 2 # 6 # 9 # 42 # 2 # 9 # 8 # 3 # 9 # 8 <lb/>16 # 1 # 8 # 0 # 2 # 7 # 0 # 43 # 2 # 10 # 6 # 3 # 10 # 6 <lb/>17 # 1 # 8 # 6 # 2 # 8 # 0 # 44 # 2 # 11 # 4 # 3 # 11 # 4 <lb/>18 # 1 # 9 # 0 # 2 # 9 # 0 # 45 # 3 # 0 # 0 # 4 # 0 # 0 <lb/>19 # 1 # 9 # 6 # 2 # 9 # 3 # 46 # 3 # 0 # 10 # 4 # 0 # 10 <lb/>20 # 1 # 10 # 0 # 2 # 9 # 6 # 47 # 3 # 1 # 8 # 4 # 1 # 8 <lb/>21 # 1 # 10 # 6 # 2 # 9 # 9 # 48 # 3 # 2 # 6 # 4 # 2 # 6 <lb/>22 # 1 # 11 # 0 # 2 # 10 # 0 # 49 # 3 # 3 # 4 # 4 # 3 # 0 <lb/>23 # 1 # 11 # 6 # 2 # 10 # 3 # 50 # 3 # 4 # 0 # 4 # 3 # 10 <lb/>24 # 2 # 0 # 0 # 2 # 10 # 6 # 51 # 3 # 4 # 10 # 4 # 4 # 8 <lb/>25 # 2 # 0 # 6 # 2 # 10 # 9 # 52 # 3 # 5 # 8 # 4 # 5 # 6 <lb/>26 # 2 # 1 # 0 # 2 # 11 # 0 # 53 # 3 # 6 # 6 # 4 # 6 # 4 <lb/>27 # 2 # 1 # 6 # 2 # 11 # 3 # 54 # 3 # 7 # 4 # 4 # 7 # 2 <lb/></note> <pb o="53" file="0161" n="164" rhead="LIIVRE II. DE LA MECANIQUE DES VOUTES."/> </div> <div xml:id="echoid-div229" type="section" level="2" n="57"> <head xml:id="echoid-head179" style="it" xml:space="preserve">SVITE DE LA TABLE.</head> <note position="right" xml:space="preserve">Ou- \\ vertu- \\ re des \\ Arches. ### Vouſſoirs de \\ Pierres dures. ### Vouſſoirs de \\ Pierres tendres. # Ouver- \\ ture des \\ Arches. ### Vouſſoirs de \\ Pierres dures. ### Vouſſoirs de \\ Pierres tendres. <lb/>pieds. # pieds. # pou. # lig. # pieds. # pou. # lig. # pieds. # pieds. # pou. # lig. # pieds. # pou. # lig. <lb/>55 # 3 # 8 # 0 # 4 # 8 # 0 # 88 # 5 # 10 # 6 # 6 # 10 # 3 <lb/>56 # 3 # 8 # 10 # 4 # 8 # 10 # 89 # 5 # 11 # 4 # 6 # 11 # 2 <lb/>57 # 3 # 9 # 8 # 4 # 9 # 7 # 90 # 6 # 0 # 0 # 7 # 0 # 0 <lb/>58 # 3 # 10 # 6 # 4 # 10 # 3 # 91 # 6 # 0 # 10 # 7 # 0 # 10 <lb/>59 # 3 # 11 # 4 # 4 # 11 # 2 # 92 # 6 # 1 # 8 # 7 # 1 # 8 <lb/>60 # 4 # 0 # 0 # 5 # 0 # 0 # 93 # 6 # 2 # 6 # 7 # 2 # 6 <lb/>61 # 4 # 0 # 10 # 5 # 0 # 10 # 94 # 6 # 3 # 4 # 7 # 3 # 0 <lb/>62 # 4 # 1 # 8 # 5 # 1 # 8 # 95 # 6 # 4 # 0 # 7 # 3 # 10 <lb/>63 # 4 # 2 # 6 # 5 # 2 # 6 # 96 # 6 # 4 # 10 # 7 # 4 # 8 <lb/>64 # 4 # 3 # 4 # 5 # 3 # 0 # 97 # 6 # 5 # 8 # 7 # 5 # 6 <lb/>65 # 4 # 4 # 0 # 5 # 3 # 10 # 98 # 6 # 6 # 6 # 7 # 6 # 4 <lb/>66 # 4 # 4 # 10 # 5 # 4 # 8 # 99 # 6 # 7 # 4 # 7 # 7 # 2 <lb/>67 # 4 # 5 # 8 # 5 # 5 # 6 # 100 # 6 # 8 # 0 # 7 # 8 # 0 <lb/>68 # 4 # 6 # 6 # 5 # 6 # 4 # 101 # 6 # 8 # 10 # 7 # 8 # 10 <lb/>69 # 4 # 7 # 0 # 5 # 7 # 2 # 102 # 6 # 9 # 8 # 7 # 9 # 7 <lb/>70 # 4 # 7 # 6 # 5 # 8 # 0 # 103 # 6 # 10 # 6 # 7 # 10 # 3 <lb/>71 # 4 # 8 # 10 # 5 # 8 # 10 # 104 # 6 # 11 # 4 # 7 # 11 # 2 <lb/>72 # 4 # 9 # 8 # 5 # 9 # 7 # 105 # 7 # 0 # 0 # 8 # 0 # 0 <lb/>73 # 4 # 10 # 6 # 5 # 10 # 3 # 106 # 7 # 0 # 10 # 8 # 0 # 10 <lb/>74 # 4 # 11 # 4 # 5 # 11 # 2 # 107 # 7 # 1 # 8 # 8 # 1 # 8 <lb/>75 # 5 # 0 # 0 # 6 # 0 # 0 # 108 # 7 # 2 # 6 # 8 # 2 # 6 <lb/>76 # 5 # 0 # 10 # 6 # 0 # 10 # 102 # 7 # 3 # 4 # 8 # 3 # 0 <lb/>77 # 5 # 1 # 8 # 6 # 1 # 8 # 110 # 7 # 4 # 0 # 8 # 3 # 10 <lb/>78 # 5 # 2 # 6 # 6 # 2 # 6 # 111 # 7 # 4 # 10 # 8 # 4 # 8 <lb/>79 # 5 # 3 # 4 # 6 # 3 # 0 # 112 # 7 # 5 # 8 # 8 # 5 # 6 <lb/>80 # 5 # 4 # 0 # 6 # 3 # 10 # 113 # 7 # 6 # 6 # 8 # 6 # 4 <lb/>81 # 5 # 4 # 10 # 6 # 4 # 8 # 114 # 7 # 7 # 4 # 8 # 7 # 2 <lb/>82 # 5 # 5 # 8 # 6 # 5 # 6 # 115 # 7 # 8 # 0 # 8 # 8 # 0 <lb/>83 # 5 # 6 # 6 # 6 # 6 # 4 # 116 # 7 # 8 # 10 # 8 # 8 # 10 <lb/>84 # 5 # 7 # 4 # 6 # 7 # 2 # 117 # 7 # 9 # 8 # 8 # 9 # 7 <lb/>85 # 5 # 8 # 0 # 6 # 8 # 0 # 118 # 7 # 10 # 6 # 8 # 10 # 3 <lb/>86 # 5 # 8 # 10 # 6 # 8 # 10 # 119 # 7 # 11 # 4 # 8 # 11 # 2 <lb/>87 # 5 # 9 # 8 # 6 # 9 # 7 # 120 # 8 # 0 # 0 # 9 # 0 # 0 <lb/></note> <pb o="54" file="0162" n="165" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div230" type="section" level="2" n="58"> <head xml:id="echoid-head180" xml:space="preserve">CHAPITRE QUATRIE’ME.</head> <p style="it"> <s xml:id="echoid-s3180" xml:space="preserve">Qui comprend des Regles pour trouver l’épaiſſeur des piés-<lb/>droits des Voûtes de toute ſorte d’eſpece, par le ſeul cal-<lb/>cul des nombres, pour l’intelligence de ceux qui ne ſavent <lb/>pas l’Algebre.</s> <s xml:id="echoid-s3181" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3182" xml:space="preserve">48. </s> <s xml:id="echoid-s3183" xml:space="preserve">JE me ſuis engagé, au commencement de ce ſecond Livre, de <lb/>donner des Régles pour trouver l’épaiſſeur des piés-droits des <lb/>Voûtes, afin de ſe paſſer du calcul Algebrique & </s> <s xml:id="echoid-s3184" xml:space="preserve">contribuer à <lb/>la ſatisfaction des perſonnes, qui, quoiqne très-habiles d’ailleurs dans <lb/>l’Architecture Militaire ou Civile, ne s’y ſont point apliquées. <lb/></s> <s xml:id="echoid-s3185" xml:space="preserve">Quand on écrit pour le public, & </s> <s xml:id="echoid-s3186" xml:space="preserve">qu’il s’agit d’un Ouvrage comme <lb/>celui-ci, il faut autant qu’il eſt poſſible faire enſorte d’être enten-<lb/>du de tout le monde, principalement de ceux qui ſe contentent <lb/>de ſavoir la pratique des choſes, & </s> <s xml:id="echoid-s3187" xml:space="preserve">qui veulent bien s’en raporter <lb/>à la bonne foy d’un Auteur; </s> <s xml:id="echoid-s3188" xml:space="preserve">ſoûmiſſion qu’il faut avoir neceſſai-<lb/>rement, quand on ne peut en juger par ſoi-même: </s> <s xml:id="echoid-s3189" xml:space="preserve">car, comme il <lb/>eſt une infinité de ſujets qu’on ne peut comprendre ſans des con-<lb/>noiſſances préliminaires, il ne dépend pas toujours de lui de ſe <lb/>rendre intelligible à ceux qui ignorent le langage dont il eſt obligé <lb/>de ſe ſervir; </s> <s xml:id="echoid-s3190" xml:space="preserve">ce qui fait, qu’avec les expreſſions les plus claires, il <lb/>n’en paroît pas moins obſcur. </s> <s xml:id="echoid-s3191" xml:space="preserve">Mais j’eſpere qu’il viendra un tems <lb/>ou les Geomêtres, les Phiſiciens, les Ingenieurs, & </s> <s xml:id="echoid-s3192" xml:space="preserve">les Architectes <lb/>penſeront à peu-près de même. </s> <s xml:id="echoid-s3193" xml:space="preserve">Il y a 80 ans, qu’on ſavoit à peine <lb/>ce que c’étoit que l’Algebre: </s> <s xml:id="echoid-s3194" xml:space="preserve">aujourd’hui, il y a peu de perſonnes <lb/>qui ſe mêlent de ſcience, qui n’en ſachent aſſés pour s’en ſervir utile-<lb/>ment; </s> <s xml:id="echoid-s3195" xml:space="preserve">& </s> <s xml:id="echoid-s3196" xml:space="preserve">je ne doute point qu’à l’avenir on ne l’aprenne auſſi com-<lb/>munément que l’Arithmetique.</s> <s xml:id="echoid-s3197" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3198" xml:space="preserve">Pour remplir parfaitement le deſſein que je me ſuis propoſé <lb/>dans ce Chapitre, je n’y ſupoſerai rien de ce qui a été dit dans les <lb/>précédens. </s> <s xml:id="echoid-s3199" xml:space="preserve">Je ferai comme ſi je commençois ſeulement à parler <lb/>des Voûtes, ce qui m’obligera à des répétitions indiſpenſables. <lb/></s> <s xml:id="echoid-s3200" xml:space="preserve">Mais comme je ne parle pas à ceux qui pourront ſe paſſer de ce <lb/>que je vais dire, ils auroient mauvaiſe grace de s’en plaindre, d’au-<lb/>tant plus qu’ils ne ſeront peut-être pas fachés de faire uſage des pra-<lb/>tiques dont il va être queſtion, pour ſe diſpenſer d’un calcul plus <lb/>compoſé; </s> <s xml:id="echoid-s3201" xml:space="preserve">car il eſt à propos que l’on ſache que les opérations, que <pb o="55" file="0163" n="166" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> l’on va faire, m’ont été fournies par les formules Algebriques, que <lb/>l’on a vûes à la fin de chaque Propoſition du 2 & </s> <s xml:id="echoid-s3202" xml:space="preserve">3 Chapitre, & </s> <s xml:id="echoid-s3203" xml:space="preserve">que <lb/>je n’aurois pû imaginer ſans leur ſecours: </s> <s xml:id="echoid-s3204" xml:space="preserve">cependant, les calculs en <lb/>ſont plus courts que ceux que l’on a vûs dans les Aplications des <lb/>mêmes Chapitres, parce que j’en ai ſuprimé quelque circonſtance <lb/>dont on pouvoit ſe paſſer; </s> <s xml:id="echoid-s3205" xml:space="preserve">& </s> <s xml:id="echoid-s3206" xml:space="preserve">en cela je me ſuis un peu relàché de <lb/>cette grande préciſion que l’on exige en matierre de Géométrie, <lb/>mais toûjours en faveur de la pratique, c’eſt-à-dire, en faveur de <lb/>la ſolidité de l’édifice que l’on voudroit conſtruire, puiſque les épaiſ-<lb/>ſeurs des piés-droits que nous allons trouver auront deux ou trois <lb/>pouces de plus que n’auroient donné les régles les plus exactes.</s> <s xml:id="echoid-s3207" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div231" type="section" level="2" n="59"> <head xml:id="echoid-head181" xml:space="preserve">PROPOSITION PREMIERE.</head> <head xml:id="echoid-head182" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s3208" xml:space="preserve">Trouver l’épaiſſeur des piés-droits d’une Voûte en plain-<lb/>ceintre, pour être en équilibre avec la pouſſée qu’ils <lb/>ont à ſoutenir.</s> <s xml:id="echoid-s3209" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3210" xml:space="preserve">49. </s> <s xml:id="echoid-s3211" xml:space="preserve">Quand on veut connoître l’épaiſſeur qu’il faut donner aux <lb/>piés-droits d’une Voûte de telle figure qu’elle puiſſe être, ſoit en <lb/>plain Ceintre, Elliptique, en tiers-point, &</s> <s xml:id="echoid-s3212" xml:space="preserve">c. </s> <s xml:id="echoid-s3213" xml:space="preserve">il faut d’abord être <lb/>prévenu de quatre choſes eſſentielles; </s> <s xml:id="echoid-s3214" xml:space="preserve">la premiere, la largeur & </s> <s xml:id="echoid-s3215" xml:space="preserve">la <lb/>hauteur de la Voûte dans œuvre; </s> <s xml:id="echoid-s3216" xml:space="preserve">la ſeconde, l’épaiſſeur de cette <lb/>Voûte à l’endroit des reins; </s> <s xml:id="echoid-s3217" xml:space="preserve">la troiſiéme, ſa figure exterieure; </s> <s xml:id="echoid-s3218" xml:space="preserve">& </s> <s xml:id="echoid-s3219" xml:space="preserve">la <lb/>quatriéme, la hauteur des piés-droits: </s> <s xml:id="echoid-s3220" xml:space="preserve">enſuite il ſuffit de ſavoir un <lb/>peu de Géométrie pratique, & </s> <s xml:id="echoid-s3221" xml:space="preserve">la racine quarrée, pour trouver le reſte <lb/>comme on le va voir dans les exemples ſuivans.</s> <s xml:id="echoid-s3222" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div232" type="section" level="2" n="60"> <head xml:id="echoid-head183" style="it" xml:space="preserve">Premier Exemple.</head> <p> <s xml:id="echoid-s3223" xml:space="preserve">50. </s> <s xml:id="echoid-s3224" xml:space="preserve">On propoſe une Voûte en plain ceintre, dont l’extrados ſeroit <lb/> <anchor type="note" xlink:label="note-0163-01a" xlink:href="note-0163-01"/> circulaire comme dans la figure 7. </s> <s xml:id="echoid-s3225" xml:space="preserve">qu’il faut conſiderer ſans ſe mettre <lb/> <anchor type="note" xlink:label="note-0163-02a" xlink:href="note-0163-02"/> en peine de la ſignificatiou des lignes dont nous ne ferons pas men-<lb/>tion; </s> <s xml:id="echoid-s3226" xml:space="preserve">on ſupoſe que la hauteur BS des piés-droits eſt de 15 pieds, le <lb/>raïon AB de 12, & </s> <s xml:id="echoid-s3227" xml:space="preserve">l’épaiſſeur de la Voûte de 3 pieds, par conſéquent <lb/>le raïon AE ou AF ſera de 15. </s> <s xml:id="echoid-s3228" xml:space="preserve">Cela poſé, pour trouver l’épaiſſeur PS <lb/>des piés-droits, il faut ſe propoſer quatre opérations.</s> <s xml:id="echoid-s3229" xml:space="preserve"/> </p> <div xml:id="echoid-div232" type="float" level="3" n="1"> <note position="right" xlink:label="note-0163-01" xlink:href="note-0163-01a" xml:space="preserve"><emph style="sc">Plan</emph>. 4.</note> <note position="right" xlink:label="note-0163-02" xlink:href="note-0163-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <p> <s xml:id="echoid-s3230" xml:space="preserve">Pour la premiere, il faut chercher la ſuperficie des deux cercles <lb/>qui auroient pour raïon AB & </s> <s xml:id="echoid-s3231" xml:space="preserve">AE; </s> <s xml:id="echoid-s3232" xml:space="preserve">(c’eſt-à-dire 12 & </s> <s xml:id="echoid-s3233" xml:space="preserve">15 pieds) <pb o="56" file="0164" n="167" rhead="LA SCIENCE DES INGENIEURS."/> prendre le quart de leur difference, (& </s> <s xml:id="echoid-s3234" xml:space="preserve">l’on aura 64 pieds quarrés) <lb/>qu’il faut diviſer par la hauteur du pié-droit; </s> <s xml:id="echoid-s3235" xml:space="preserve">(c’eſt-à-dire par 15) & </s> <s xml:id="echoid-s3236" xml:space="preserve"><lb/>le quotient donnera 4 pieds 3 pouces 4 lignes, que nous nomme-<lb/>rons premier terme.</s> <s xml:id="echoid-s3237" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3238" xml:space="preserve">Pour la ſeconde, il faut ajoûter au raïon AC la moitié de l’épaiſ-<lb/>ſeur de la Voûte, pour avoir la ligne AL de (13 pieds & </s> <s xml:id="echoid-s3239" xml:space="preserve">demi) <lb/>qu’il faut quarrer & </s> <s xml:id="echoid-s3240" xml:space="preserve">prendre la moitié du produit (c’eſt-à-dire 91 <lb/>pieds 1 pouce 6 lignes) & </s> <s xml:id="echoid-s3241" xml:space="preserve">en extraire la racine quarrée (qu’on trou-<lb/>vera de 9 pieds 10 pouces) qu’on ajoûtera à la hauteur du pié-droit, <lb/>& </s> <s xml:id="echoid-s3242" xml:space="preserve">l’on aura 24 pieds 10 pouces que nous nommerons deuxiéme <lb/>terme.</s> <s xml:id="echoid-s3243" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3244" xml:space="preserve">Pour la troiſiéme, il faut ajoûter enſemble le premier & </s> <s xml:id="echoid-s3245" xml:space="preserve">le ſecond <lb/>termes, (c’eſt-à-dire 4 pieds 3 pouces 4 lignes, & </s> <s xml:id="echoid-s3246" xml:space="preserve">24 pieds 10 pouces, <lb/>pour avoir 29 pieds 1 pouce 4 lignes,) qu’on multipliera par le <lb/>premier (4 pieds 3 pouces 4 lignes) & </s> <s xml:id="echoid-s3247" xml:space="preserve">le produit donnera 124 <lb/>pieds 6 pouces 4 lignes, pour la valeur du troiſiéme terme.</s> <s xml:id="echoid-s3248" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3249" xml:space="preserve">Enfin, pour la quatriéme opération, il faut extraire la racine quar-<lb/>rée du 3 terme, (j’entends de 124 pieds 6 pouces 4 lignes) qui <lb/>eſt à peu-près 11 pieds 1 pouce 8 lignes) & </s> <s xml:id="echoid-s3250" xml:space="preserve">en ſouſtraire la valeur <lb/>du premier, (c’eſt-à-dire 4 pieds 3 pouces 4 lignes,) la difference, <lb/>qui eſt 6 pieds 10 pouces 4 lignes, ſera l’épaiſſeur qu’il faut donner <lb/>aux piés-droits.</s> <s xml:id="echoid-s3251" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div234" type="section" level="2" n="61"> <head xml:id="echoid-head184" style="it" xml:space="preserve">Second Exemple.</head> <p> <s xml:id="echoid-s3252" xml:space="preserve">51. </s> <s xml:id="echoid-s3253" xml:space="preserve">Si l’on avoit une Voûte en plain ceintre, dont l’extrados, <lb/> <anchor type="note" xlink:label="note-0164-01a" xlink:href="note-0164-01"/> au lieu d’être circulaire, fut terminée par deux plans GH & </s> <s xml:id="echoid-s3254" xml:space="preserve">GI, <lb/> <anchor type="note" xlink:label="note-0164-02a" xlink:href="note-0164-02"/> comme dans la figure 10. </s> <s xml:id="echoid-s3255" xml:space="preserve">l’on trouvera l’épaiſſeur de ſes piés-droits <lb/>en faiſant encore quatre opérations ſemblables aux précédentes, <lb/>puiſqu’il n’y aura que la premiere qui ſera un peu differente à cauſe <lb/>que la Voûte n’eſt pas la même que cy-devant.</s> <s xml:id="echoid-s3256" xml:space="preserve"/> </p> <div xml:id="echoid-div234" type="float" level="3" n="1"> <note position="left" xlink:label="note-0164-01" xlink:href="note-0164-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>4.</note> <note position="left" xlink:label="note-0164-02" xlink:href="note-0164-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 10.</note> </div> <p> <s xml:id="echoid-s3257" xml:space="preserve">Supoſant le raïon AB de 12 pieds, la hauteur BS des piés-droits <lb/>de 15, l’épaiſſeur FC de 3 dans le milieu des reins, & </s> <s xml:id="echoid-s3258" xml:space="preserve">que l’angle <lb/>HGI ſoit droit, on aura le quarré AFGW, dont le côté AF ſera de <lb/>de 15 pieds.</s> <s xml:id="echoid-s3259" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3260" xml:space="preserve">Cela poſé, pour la premiere opération il faut chercher la ſuper-<lb/>ſicie du quarré GF AW, & </s> <s xml:id="echoid-s3261" xml:space="preserve">en retrancher le quart de cercle CA, <lb/>&</s> <s xml:id="echoid-s3262" xml:space="preserve">c. </s> <s xml:id="echoid-s3263" xml:space="preserve">diviſer la difference (qui ſera 112 pieds) par la hauteur BS des <lb/>piés-droits, (c’eſt-à-dire par 15 pieds) & </s> <s xml:id="echoid-s3264" xml:space="preserve">le quotient donnera 7 <lb/>pieds 5 pouces 7 lignes, pour la valeur du premier terme.</s> <s xml:id="echoid-s3265" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3266" xml:space="preserve">La ſeconde opération ſe fera en ajoûtant la moitié de l’épaiſ-<lb/>ſeur de la Voûte FC au raïon AB pour avoir la ligne LA (de 13 <pb o="57" file="0165" n="168" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> pieds & </s> <s xml:id="echoid-s3267" xml:space="preserve">demi) qu’il faudra quarrer, prendre la moitié du produit, <lb/>dont on extraira la racine (qui ſera de 9 pieds 10 pouces) qu’on <lb/>ajoutera à la hauteur du pié-droit, pour avoir 24 pieds 10 pouces, <lb/>valeur du ſecond terme.</s> <s xml:id="echoid-s3268" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3269" xml:space="preserve">Pour la troiſiéme opération, il faut ajoûter le premier terme <lb/>(7 pieds 5 pouces 7 lignes) au ſecond (24 pieds 10 pouces) mul-<lb/>tiplier leur ſomme (qui eſt 32 pieds 3 pouces 7 lignes,) par le <lb/>premier (7 pieds 5 pouces 7 lignes,) & </s> <s xml:id="echoid-s3270" xml:space="preserve">le produit ſera 241 pieds <lb/>1 pouce 3 lignes, pour le troiſième terme.</s> <s xml:id="echoid-s3271" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3272" xml:space="preserve">Enfin, pour la quatriéme opération, on extraira la racine quarrée <lb/>du troiſiéme terme (241 pieds 1 pouce 3 lignes, & </s> <s xml:id="echoid-s3273" xml:space="preserve">on trouvera <lb/>qu’elle eſt de 15 pieds 6 pouces 2 lignes,) d’où il faut ſouſtraire <lb/>la valeur du premier terme, (7 pieds 5 pouces 7 lignes,) la diffe-<lb/>rence ſera 8 pieds 7 lignes pour l’épaiſſeur qu’il faut donner aux <lb/>piés-droits.</s> <s xml:id="echoid-s3274" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div236" type="section" level="2" n="62"> <head xml:id="echoid-head185" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s3275" xml:space="preserve">52. </s> <s xml:id="echoid-s3276" xml:space="preserve">Je viens de ſupoſer que l’angle HGI étoit droit; </s> <s xml:id="echoid-s3277" xml:space="preserve">mais s’il <lb/>étoit obtus ou aigu, il faudroit encore chercher la ſuperficie du <lb/>quadrilataire AFGW, & </s> <s xml:id="echoid-s3278" xml:space="preserve">en retrancher toujours le quart de cercle <lb/>CA, &</s> <s xml:id="echoid-s3279" xml:space="preserve">c. </s> <s xml:id="echoid-s3280" xml:space="preserve">car tel que puiſſe être ce quadrilataire, on aura ſans doute <lb/>l’épaiſſeur GB au ſommet de la Voûte, par conſéquent la ligne GA, <lb/>& </s> <s xml:id="echoid-s3281" xml:space="preserve">l’autre AF, auſſi-bien que l’angle FAG, qui ſuffiront pour con-<lb/>noître le reſte.</s> <s xml:id="echoid-s3282" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div237" type="section" level="2" n="63"> <head xml:id="echoid-head186" style="it" xml:space="preserve">Troiſiéme Exemple.</head> <p> <s xml:id="echoid-s3283" xml:space="preserve">53. </s> <s xml:id="echoid-s3284" xml:space="preserve">Si le deſſus de la Voûte étoit terminé par une plate-forme, <lb/> <anchor type="note" xlink:label="note-0165-01a" xlink:href="note-0165-01"/> comme dans la figure 11. </s> <s xml:id="echoid-s3285" xml:space="preserve">il ſuffira de connoître l’épaiſſeur GD de <lb/> <anchor type="note" xlink:label="note-0165-02a" xlink:href="note-0165-02"/> cette Voûte à l’endroit de la clef, le raïon AB, & </s> <s xml:id="echoid-s3286" xml:space="preserve">la hauteur BS <lb/>des piés-droits, pour avoir l’épaiſſeur PS, en faiſant encore quatre <lb/>opérations.</s> <s xml:id="echoid-s3287" xml:space="preserve"/> </p> <div xml:id="echoid-div237" type="float" level="3" n="1"> <note position="right" xlink:label="note-0165-01" xlink:href="note-0165-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>4.</note> <note position="right" xlink:label="note-0165-02" xlink:href="note-0165-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 11.</note> </div> <p> <s xml:id="echoid-s3288" xml:space="preserve">Pour la premiere, il faut quarrer la ligne G A compoſée du raïon <lb/>& </s> <s xml:id="echoid-s3289" xml:space="preserve">de l’épaiſſeur de la Voûte, du produit en ſouſtraire le quart de <lb/>cercle CAr, & </s> <s xml:id="echoid-s3290" xml:space="preserve">diviſer la difference par la hauteur des piés-droits, <lb/>afin d’avoir le premier terme; </s> <s xml:id="echoid-s3291" xml:space="preserve">à l’égard des trois autres opérations <lb/>comme elles ſont toutes ſemblables à celles des deux exemples pré-<lb/>cedens, il eſt inutile de les répéter.</s> <s xml:id="echoid-s3292" xml:space="preserve"/> </p> <pb o="58" file="0166" n="169" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div239" type="section" level="2" n="64"> <head xml:id="echoid-head187" xml:space="preserve">PROPOSITION SECONDE</head> <head xml:id="echoid-head188" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s3293" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux piés-droits des <lb/>Voûtes Elliptiques ou ſurbaiſſées.</s> <s xml:id="echoid-s3294" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3295" xml:space="preserve">54. </s> <s xml:id="echoid-s3296" xml:space="preserve">Pouravoirune parfaite intelligence de ce Probléme, je con-<lb/>ſeille à ceux qui ne ſe ſont point apliqués au Chapitre précédent, <lb/>de lire avec attention l’Article 30. </s> <s xml:id="echoid-s3297" xml:space="preserve">où il eſt parlé de la maniere de <lb/>tracer une Ellipſe, ce qui leur ſuffira pour me ſuivre.</s> <s xml:id="echoid-s3298" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3299" xml:space="preserve">Ayant une Voûte Elliptique comme dans la figure 8. </s> <s xml:id="echoid-s3300" xml:space="preserve">dont on <lb/>connoît les demi axes BH & </s> <s xml:id="echoid-s3301" xml:space="preserve">HD, on commencera par diviſer le <lb/> <anchor type="note" xlink:label="note-0166-01a" xlink:href="note-0166-01"/> quart d’Ellipſe BD en deux également au point L, duquel on abaiſ-<lb/> <anchor type="note" xlink:label="note-0166-02a" xlink:href="note-0166-02"/> ſera ſur DH & </s> <s xml:id="echoid-s3302" xml:space="preserve">HB les perpendiculaires LK & </s> <s xml:id="echoid-s3303" xml:space="preserve">LV, dont on cher-<lb/>chera la valeur avec le ſecours de l’échelle; </s> <s xml:id="echoid-s3304" xml:space="preserve">& </s> <s xml:id="echoid-s3305" xml:space="preserve">ſupoſant que BH <lb/>ſoit de 12 pieds, & </s> <s xml:id="echoid-s3306" xml:space="preserve">HD de 8, on trouvera que LK ou VH eſt de 7 <lb/>pieds 6 pouces, & </s> <s xml:id="echoid-s3307" xml:space="preserve">LV ou KH de 6 pieds 3 pouces; </s> <s xml:id="echoid-s3308" xml:space="preserve">& </s> <s xml:id="echoid-s3309" xml:space="preserve">faiſant la <lb/>hauteur BS du pié-droit de 15 pieds, comme à l’ordinaire, il faut <lb/>pour en avoir l’épaiſſeur ſe propoſer cinq opérations.</s> <s xml:id="echoid-s3310" xml:space="preserve"/> </p> <div xml:id="echoid-div239" type="float" level="3" n="1"> <note position="left" xlink:label="note-0166-01" xlink:href="note-0166-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>5.</note> <note position="left" xlink:label="note-0166-02" xlink:href="note-0166-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> <p> <s xml:id="echoid-s3311" xml:space="preserve">Pour la premiere, il faut dire, comme le quarré de DH (de 64 <lb/>pieds) eſt au quarré de BH (de 144,) ainſi la ligne KH (de 6 pieds <lb/>3 pouces) eſt à la ligne KA, qu’on trouvera de 14 pieds 9 lignes, <lb/>qui eſt le premier terme dont nous avons beſoin.</s> <s xml:id="echoid-s3312" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3313" xml:space="preserve">Pour la ſeconde opération, il faut chercher la ſuperficie des <lb/>deux Ellipſes, dont la premiere auroit pour demi axe BH & </s> <s xml:id="echoid-s3314" xml:space="preserve">HD, <lb/>(de 12 pieds & </s> <s xml:id="echoid-s3315" xml:space="preserve">de 8,) & </s> <s xml:id="echoid-s3316" xml:space="preserve">la ſeconde pour demi axe HE & </s> <s xml:id="echoid-s3317" xml:space="preserve">HG, <lb/>(de 15 & </s> <s xml:id="echoid-s3318" xml:space="preserve">de 4, parce qu’on ſupoſe que la Voûte a encore 3 pieds <lb/>d’épaiſſeur,) on retranchera la petite Ellipſe de la grande, & </s> <s xml:id="echoid-s3319" xml:space="preserve">on <lb/>prendra le quart de la difference (que l’on trouvera de 54 pieds) <lb/>qu’il faut diviſer par la hauteur du pié-droit, le quotient ſera 3 pieds <lb/>2 pouces 4 lignes, pour le ſecond terme.</s> <s xml:id="echoid-s3320" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3321" xml:space="preserve">Pour la troiſiéme opération, il faut ajoûter la ligne LV (qu’on <lb/>a trouvée de 6 pieds 3 pouces) à la hauteur du pié-droit, (pour <lb/>avoir 21 pieds 3 pouces) qu’il faut multiplier par le premier terme <lb/>(14 pieds 9 pouces) & </s> <s xml:id="echoid-s3322" xml:space="preserve">diviſer le produit par la valeur de LK) qui <lb/>eſt de 7 pieds 6 pouces,) le quotient ſera d’environ 41 pieds 10 <lb/>pouces pour le troiſiéme terme.</s> <s xml:id="echoid-s3323" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3324" xml:space="preserve">A l’égard de la quatriéme, il faut ajoûter le ſecond terme au <pb o="59" file="0167" n="170" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> troiſiéme (pour avoir 41 pieds 10 pouces,) qu’on multipliera par <lb/>la valeur du ſecond, (c’eſt-à-dire par 3 pieds 2 pouces,) & </s> <s xml:id="echoid-s3325" xml:space="preserve">le pro-<lb/>duit ſera à peu-près 144, pour le quatriéme terme.</s> <s xml:id="echoid-s3326" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3327" xml:space="preserve">Enfin, la cinquiéme opération ſe fera en extrayant la racine quar-<lb/>rée du quatriéme terme, (ce qui ſera de 12 pieds) de laquelle il <lb/>faut ſouſtraire le ſecond, (3 pieds 2 pouces 4 lignes,) & </s> <s xml:id="echoid-s3328" xml:space="preserve">la diffe-<lb/>rence donnera 8 pieds 9 pouces 8 lignes, pour l’épaiſſeur des piés-<lb/>droits.</s> <s xml:id="echoid-s3329" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div241" type="section" level="2" n="65"> <head xml:id="echoid-head189" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s3330" xml:space="preserve">55. </s> <s xml:id="echoid-s3331" xml:space="preserve">Si l’extrados de la Voûte, au lieu d’être Elliptique, étoit ter-<lb/> <anchor type="note" xlink:label="note-0167-01a" xlink:href="note-0167-01"/> miné par deux plans 5. </s> <s xml:id="echoid-s3332" xml:space="preserve">6. </s> <s xml:id="echoid-s3333" xml:space="preserve">& </s> <s xml:id="echoid-s3334" xml:space="preserve">5. </s> <s xml:id="echoid-s3335" xml:space="preserve">4. </s> <s xml:id="echoid-s3336" xml:space="preserve">comme on le pratique aux Ma-<lb/>gaſins à Poudre & </s> <s xml:id="echoid-s3337" xml:space="preserve">aux Souterains, il faudroit, au lieu de ſuivre ce <lb/>qui eſt dit dans la ſeconde opération, chercher la ſuperſicie du qua-<lb/>drilataire AF 5. </s> <s xml:id="echoid-s3338" xml:space="preserve">3. </s> <s xml:id="echoid-s3339" xml:space="preserve">(formé par l’angle F 5. </s> <s xml:id="echoid-s3340" xml:space="preserve">3. </s> <s xml:id="echoid-s3341" xml:space="preserve">& </s> <s xml:id="echoid-s3342" xml:space="preserve">les deux lignes AF <lb/>& </s> <s xml:id="echoid-s3343" xml:space="preserve">A 3. </s> <s xml:id="echoid-s3344" xml:space="preserve">qui ont été tirées des points L & </s> <s xml:id="echoid-s3345" xml:space="preserve">2 milieux des quarts d’El-<lb/>lipſes DB & </s> <s xml:id="echoid-s3346" xml:space="preserve">D 7. </s> <s xml:id="echoid-s3347" xml:space="preserve">au point A que l’on a trouvé par la premiere <lb/>opération,) en ſouſtraire la figure mixtiligne ALD 2. </s> <s xml:id="echoid-s3348" xml:space="preserve">& </s> <s xml:id="echoid-s3349" xml:space="preserve">diviſer le <lb/>reſtant par la hauteur du pié-droit aſin d’avoir un quotient qui don-<lb/>nera le ſecond terme: </s> <s xml:id="echoid-s3350" xml:space="preserve">quant aux autres opérations, elles ſont les mê-<lb/>mes que celles dont nous venons de parler.</s> <s xml:id="echoid-s3351" xml:space="preserve"/> </p> <div xml:id="echoid-div241" type="float" level="3" n="1"> <note position="right" xlink:label="note-0167-01" xlink:href="note-0167-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> </div> <div xml:id="echoid-div243" type="section" level="2" n="66"> <head xml:id="echoid-head190" xml:space="preserve">PROPOSITION TROISIE’ME.</head> <head xml:id="echoid-head191" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s3352" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux piés-droits des <lb/>Voûtes en tiers-points.</s> <s xml:id="echoid-s3353" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3354" xml:space="preserve">56. </s> <s xml:id="echoid-s3355" xml:space="preserve">Ayant une Voûte en tiers-point dont on veut connoître l’é-<lb/> <anchor type="note" xlink:label="note-0167-02a" xlink:href="note-0167-02"/> paiſſeur des piés-droits, il faut ſavoir d’abord à quelle diſtance les <lb/> <anchor type="note" xlink:label="note-0167-03a" xlink:href="note-0167-03"/> centres G & </s> <s xml:id="echoid-s3356" xml:space="preserve">H, qui ont ſervi à décrire les deux arcs de la. </s> <s xml:id="echoid-s3357" xml:space="preserve">Voûte, <lb/>ſont du point A milieu de BI, leur poſition étant arbitraire dépen-<lb/>dant du plus ou moins d’élevation qu’on veut donner à la Voûte, <lb/>il faut ſavoir comme onles a déterminés & </s> <s xml:id="echoid-s3358" xml:space="preserve">toûjours dans la ligne BI; <lb/></s> <s xml:id="echoid-s3359" xml:space="preserve">car s’ils étoient au-deſſus ou au-deſſous commeje l’ai vû dans quel-<lb/>que ouvrage aſſés mal conçû, la Voûte ſeroit très-deffectueuſe, parce <lb/>que ſon impoſte feroit un jarret avec le pié-droit, & </s> <s xml:id="echoid-s3360" xml:space="preserve">auroit beau-<lb/>coup moins de force pour réſiſter au choc des Bombes, ſi on la <lb/>conſtruiſoit pour couvrir un Magaſin à Poudre ou quelqu’autre Edi- <pb o="60" file="0168" n="171" rhead="LA SCIENCE DES INGENIEURS,"/> fice Militaire. </s> <s xml:id="echoid-s3361" xml:space="preserve">Nous ſupoſerons donc qu’ils ſont dans le milieu des <lb/>lignes BA & </s> <s xml:id="echoid-s3362" xml:space="preserve">AI, qui étant chacune de 12 pieds HB ou HD ſera <lb/>de 18, & </s> <s xml:id="echoid-s3363" xml:space="preserve">HA de 6. </s> <s xml:id="echoid-s3364" xml:space="preserve">de l’autre côté faiſant la Voûte de 3 pieds d’épaiſ-<lb/>ſeur, & </s> <s xml:id="echoid-s3365" xml:space="preserve">donnant encore 15 pieds à la hauteur BS des piés-droits, on <lb/>trouvera le reſte en ſuivant les cinq opérations que voici.</s> <s xml:id="echoid-s3366" xml:space="preserve"/> </p> <div xml:id="echoid-div243" type="float" level="3" n="1"> <note position="right" xlink:label="note-0167-02" xlink:href="note-0167-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>6.</note> <note position="right" xlink:label="note-0167-03" xlink:href="note-0167-03a" xml:space="preserve"><emph style="sc">Fig</emph>. 1.</note> </div> <p> <s xml:id="echoid-s3367" xml:space="preserve">Pour la premiere opération, il faut chercher par la trigonome-<lb/>trie l’angle AHD du triangle rectangle DAH, duquel on connoît <lb/>les deux côtés DH & </s> <s xml:id="echoid-s3368" xml:space="preserve">HA, (& </s> <s xml:id="echoid-s3369" xml:space="preserve">on trouvera qu’il eſt de 70 degrès <lb/>30 minutes.</s> <s xml:id="echoid-s3370" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3371" xml:space="preserve">Pour la ſeconde, il faut chercher la ſuperficie des deux cercles <lb/>qui auroient pour raïon HB & </s> <s xml:id="echoid-s3372" xml:space="preserve">HE (de 18 & </s> <s xml:id="echoid-s3373" xml:space="preserve">de 21 pieds,) en pren-<lb/>dre la difference (qu’on trouvera de 368 pieds quarrés,) enſuite <lb/>dire, comme 360 degrés eſt à la valeur de l’angle DHB (de 70 de-<lb/>grés 30 minutes, que l’on a trouvé dans l’opération précédente,) <lb/>ainſi la difference des deux cercles (368) eſt à un quatriéme terme <lb/>(qu’on trouvera de 71 pieds 6 pouces 8 lignes) qu’il faut diviſer <lb/>par la hauteur (15) des piés-droits, & </s> <s xml:id="echoid-s3374" xml:space="preserve">le quotient ſera 4 pieds 9 <lb/>pouces 3 lignes, pour le premier terme.</s> <s xml:id="echoid-s3375" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3376" xml:space="preserve">Pour la troiſiéme, on tirera la ligne HF par le milieu C de l’arc <lb/>BD (qui donnera 35 degrés 15 minutes pour l’angle LHV, par <lb/>la premiere opération) & </s> <s xml:id="echoid-s3377" xml:space="preserve">du point L milieu de FC, on abaiſſera <lb/>la perpendiculaire LV, on aura le triangle rectangle LVH, duquel <lb/>on connoît les angles & </s> <s xml:id="echoid-s3378" xml:space="preserve">le côté HL (de 19 pieds & </s> <s xml:id="echoid-s3379" xml:space="preserve">demi,) ainſi <lb/>par les calculs ordinaires on trouvera 11 pieds 3 pouces pour le <lb/>côté LV, & </s> <s xml:id="echoid-s3380" xml:space="preserve">16 pieds pour l’autre VH; </s> <s xml:id="echoid-s3381" xml:space="preserve">& </s> <s xml:id="echoid-s3382" xml:space="preserve">pour ne pas confondre <lb/>ces deux grandeurs dans les calculs ſuivans, nous nommerons 11 <lb/>pieds 3 pouces, ſecond terme, & </s> <s xml:id="echoid-s3383" xml:space="preserve">16 pieds, troiſiéme terme.</s> <s xml:id="echoid-s3384" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3385" xml:space="preserve">Pour la quatriéme opération, il faut ajoûter le ſecond terme (11 <lb/>pieds 3 pouces) à la hauteur du pié-droit (& </s> <s xml:id="echoid-s3386" xml:space="preserve">l’on aura 29 pieds 3 <lb/>pouces,) qu’on multipliera par le ſecond terme même; </s> <s xml:id="echoid-s3387" xml:space="preserve">c’eſt-à-<lb/>dire par 11 pieds 3 pouces,) diviſer le produit (295 pieds 4 pou-<lb/>ces,) par le troiſiéme (j’entends par 16 pieds, ajoûter le quotient <lb/>(18 pieds 5 pouces 6 lignes) au premier terme, (4 pieds 9 pou-<lb/>ces 3 lignes) & </s> <s xml:id="echoid-s3388" xml:space="preserve">multiplier la ſomme (qui eſt 23 pieds 2 pouces <lb/>2 lignes) par le premier terme (4 pieds 9 pouces 3 lignes,) le pro-<lb/>duit ſera environ (110 pieds 9 pouces 9 lignes) pour le quatriéme <lb/>terme.</s> <s xml:id="echoid-s3389" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3390" xml:space="preserve">Enfin, pour la cinquiéme opération, on extraira la racine quarrée <lb/>du quatriéme terme; </s> <s xml:id="echoid-s3391" xml:space="preserve">(c’eſt-à-dire de 110 pieds 9 pouces 9 lignes, <lb/>qu’on trouvera d’environ 10 pieds 6 pouces 2 lignes) d’où il faut <lb/>ſouſtraire le premier terme, (4 pieds 9 pouces 3 lignes,) la diffe- <pb o="61" file="0169" n="172" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> rence ſera 5 pieds 8 pouces 11 lignes, qui eſt l’épaiſſeur qu’il faut <lb/>donner aux piés-droits.</s> <s xml:id="echoid-s3392" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div245" type="section" level="2" n="67"> <head xml:id="echoid-head192" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s3393" xml:space="preserve">57. </s> <s xml:id="echoid-s3394" xml:space="preserve">Si l’extrados de la Voûte, au lieu d’être curviligne comme <lb/>nous le venons de ſupoſer, étoit terminé par deux plans 5. </s> <s xml:id="echoid-s3395" xml:space="preserve">4. </s> <s xml:id="echoid-s3396" xml:space="preserve">& </s> <s xml:id="echoid-s3397" xml:space="preserve">5. </s> <s xml:id="echoid-s3398" xml:space="preserve">6. <lb/></s> <s xml:id="echoid-s3399" xml:space="preserve">il faudroit dans la ſeconde opération chercher la valeur du qua-<lb/>drilataire QF 5. </s> <s xml:id="echoid-s3400" xml:space="preserve">3. </s> <s xml:id="echoid-s3401" xml:space="preserve">(formé par l’angle F 5. </s> <s xml:id="echoid-s3402" xml:space="preserve">3. </s> <s xml:id="echoid-s3403" xml:space="preserve">& </s> <s xml:id="echoid-s3404" xml:space="preserve">les deux lignes QF <lb/>& </s> <s xml:id="echoid-s3405" xml:space="preserve">Q 3, qui ont été tirées des centres G & </s> <s xml:id="echoid-s3406" xml:space="preserve">H, pour diviſer les arcs <lb/>DB & </s> <s xml:id="echoid-s3407" xml:space="preserve">DI en deux également) en retrancher la figure mixtiligne <lb/>QCD2, & </s> <s xml:id="echoid-s3408" xml:space="preserve">diviſer le reſtant par la hauteur du pié-droit, le quotient <lb/>ſera le premier terme. </s> <s xml:id="echoid-s3409" xml:space="preserve">A l’égard des autres opérations, elles doivent <lb/>être de même que les précédentes.</s> <s xml:id="echoid-s3410" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div246" type="section" level="2" n="68"> <head xml:id="echoid-head193" xml:space="preserve">PROPOSITION QUATRIE’ME.</head> <head xml:id="echoid-head194" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s3411" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux piés-droits qui <lb/>ſoûtiendroient une Plate-Bande.</s> <s xml:id="echoid-s3412" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3413" xml:space="preserve">58. </s> <s xml:id="echoid-s3414" xml:space="preserve">La Plate-Bande eſt une eſpece de Voûte qui a la figure d’un <lb/> <anchor type="note" xlink:label="note-0169-01a" xlink:href="note-0169-01"/> Plat-Fond; </s> <s xml:id="echoid-s3415" xml:space="preserve">ſon uſage le plus ordinaire eſt d’être employée dans les <lb/> <anchor type="note" xlink:label="note-0169-02a" xlink:href="note-0169-02"/> grands édifices, où il y a des periſtiles, comme au vieux Louvre à <lb/>Paris, ou bien on s’en ſert aux Portes-Cocheres; </s> <s xml:id="echoid-s3416" xml:space="preserve">& </s> <s xml:id="echoid-s3417" xml:space="preserve">alors comme <lb/>cette Voûte a beaucoup de pouſſée, on peut, pour la ſoulager du <lb/>poids qu’elle auroit à porter, faire un arc de décharge comme je <lb/>l’ai dit ailleurs. </s> <s xml:id="echoid-s3418" xml:space="preserve">Mr. </s> <s xml:id="echoid-s3419" xml:space="preserve">Abeille, Ingenieur du Canal de Picardie, a ima-<lb/>giné une conſtruction de plate-bande fort ingenieuſe; </s> <s xml:id="echoid-s3420" xml:space="preserve">la coupe des <lb/>Clavaux en eſt ſinguliere, & </s> <s xml:id="echoid-s3421" xml:space="preserve">contribuë beaucoup à diminuer la pouſ-<lb/>ſée queles piés-droits auroient à ſoûtenir: </s> <s xml:id="echoid-s3422" xml:space="preserve">j’en aurois volontiers fait <lb/>la deſcription, ſi elle étoit venuë à ma connoiſſance avant que les <lb/>Planches de ce ſecond Livre fuſſent gravées.</s> <s xml:id="echoid-s3423" xml:space="preserve"/> </p> <div xml:id="echoid-div246" type="float" level="3" n="1"> <note position="right" xlink:label="note-0169-01" xlink:href="note-0169-01a" xml:space="preserve"><emph style="sc">Planch</emph> <lb/>6.</note> <note position="right" xlink:label="note-0169-02" xlink:href="note-0169-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 2.</note> </div> <p> <s xml:id="echoid-s3424" xml:space="preserve">Quand on veut conſtruire une plate-bande LDEF, on décrit ſur <lb/>la ligne LF qui en doit déterminer l’étenduë, un triangle équilateral <lb/>LAF, dont le point A ſert de centre pour trouver la coupe des Cla-<lb/>vaux, ainſi les lignes LD & </s> <s xml:id="echoid-s3425" xml:space="preserve">EF, (qui ne ſont autre choſe que les <lb/>côtés du triangle prolongé,) marquent les joints des deux derniers <lb/>Clavaux qui s’apuyent ſur les couſſinets, deſorte que c’eſt le Trapeze <lb/>LDEF, qui cauſe la pouſſée que les piés-droits ont à ſoûtenir: </s> <s xml:id="echoid-s3426" xml:space="preserve">or ſi <lb/>l’on ſupoſe la ligne LF de 24 pieds, l’épaiſſeur CK de 3, & </s> <s xml:id="echoid-s3427" xml:space="preserve">la hau- <pb o="62" file="0170" n="173" rhead="LA SCIENCE DES INGENIEURS,"/> teur LS des piés-droits de 15, il faut pour en trouver l’épaiſſeur ſe <lb/>propoſer quatre opérations.</s> <s xml:id="echoid-s3428" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3429" xml:space="preserve">La premiere eſt de chercher la valeur de la perpendiculaire AK <lb/>par le moyen du triangle LAK, dont le côté LA étant double de <lb/>LK, l’un ſera de 12, & </s> <s xml:id="echoid-s3430" xml:space="preserve">l’autre de 24, qui donneront 20 pieds 9 pou-<lb/>ces 4 lignes pour KA, que nous nommerons premier terme.</s> <s xml:id="echoid-s3431" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3432" xml:space="preserve">La deuxiéme, eſt de chercher la ſuperficie du Trapeze LDCK, <lb/>(que l’on trouvera d’environ 38 pieds 3 pouces,) qu’il faut diviſer <lb/>par la hauteur du pié-droit (qui eſt de 15) & </s> <s xml:id="echoid-s3433" xml:space="preserve">l’on aura 2 pieds 6 pou-<lb/>ces 7 lignes, pour le ſecond terme.</s> <s xml:id="echoid-s3434" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3435" xml:space="preserve">Pour la troiſiéme il faut diviſer la valeur de la ligne AK, (c’eſt-<lb/>à-dire 20 pieds 9 pouces 4 lignes,) par le quart de la largeur LF <lb/>de la plate-bande (qui eſt 6) multiplier le quotient (3 pieds 5 pou-<lb/>ces 6 lignes,) par la ſuperficie du Trapeze LDCK (que l’on a trou-<lb/>vé dans la ſeconde opération de 38 pieds 3 pouces) & </s> <s xml:id="echoid-s3436" xml:space="preserve">le produit ſera <lb/>2 pieds 3 pouces 4 lignes, pour le troiſiéme terme.</s> <s xml:id="echoid-s3437" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3438" xml:space="preserve">Enfin, pour la quatrieme opération, il faut quarrer le 2<emph style="sub">e</emph> terme <lb/>(2 pieds 6 pouces 7 lignes) & </s> <s xml:id="echoid-s3439" xml:space="preserve">ajoûter le produit (6 pieds 5 pouces <lb/>9 lignes) au troiſiéme, (2 pieds 3 pouces 4 lignes) de la ſomme (qui <lb/>eſt 138 pieds 9 pouces 1 ligne) extraire la racine quarrée (qui ſera <lb/>de 11 pieds 9 pouces 4 lignes,) de laquelle retranchant la valeur du <lb/>ſecond terme, (j’entends 2 pieds 6 pouces 7 lignes) la difference <lb/>9 pieds 2 pouces 9 lignes, ſera l’épaiſſeur qu’il faut donner aux piés-<lb/>droits pour ſoûtenir la pouſſée de la plate-bande dans l’état d’équili-<lb/>bre.</s> <s xml:id="echoid-s3440" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div248" type="section" level="2" n="69"> <head xml:id="echoid-head195" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s3441" xml:space="preserve">58. </s> <s xml:id="echoid-s3442" xml:space="preserve">Quoique les Regles, que nous venons d’enſeigner dans les qua-<lb/>tre Problémes précédens, ayent donné un peu plus d’épaiſſeur <lb/>qu’il ne faloit aux piés-droits pour être en équilibre avec la pouſſée <lb/>qu’ils avoient à ſoûtenir, on prendra garde que cette petite augmen-<lb/>tation ne ſuffit pas dans la pratique où il faut que la puiſſance ré-<lb/>ſiſtante ſoit toûjours beaucoup au-deſſus de celle qui agit, afin que <lb/>l’ouvrage en ſoit plus ſolide; </s> <s xml:id="echoid-s3443" xml:space="preserve">c’eſt pourquoi il eſt à propos d’en aug-<lb/>menter l’épaiſſeur d’un ſixiéme de ce qu’on aura trouvé par le cal-<lb/>cul; </s> <s xml:id="echoid-s3444" xml:space="preserve">ou bien, ſi on l’aime mieux, on pourra ſans y faire aucune aug-<lb/>mentation fortifier les piés-droits par des contreſorts, qui eſt le par-<lb/>ti le plus convenable & </s> <s xml:id="echoid-s3445" xml:space="preserve">le plus conſorme à l’uſage, du moins quand <lb/>il s’agit des ouvrages qui ont raport à la Fortification, étant les ſeuls <lb/>que j’ai enviſagé. </s> <s xml:id="echoid-s3446" xml:space="preserve">Car j’aurois pû dans les Chapitres précédens, auſſi-<lb/>bien que dans celui-ci, parler de la conſtruction des Voûtes des Egliſes <pb o="63" file="0171" n="174" rhead="LIVRE II. DE LA MECANIQUE DES VOUTES."/> & </s> <s xml:id="echoid-s3447" xml:space="preserve">de celles des autres Edifices qui demandent de la légereté & </s> <s xml:id="echoid-s3448" xml:space="preserve">une <lb/>certaine hardieſſe; </s> <s xml:id="echoid-s3449" xml:space="preserve">peut-être même que les idées que j’ai là-deſſus <lb/>pourroient meriter l’attention des Curieux, principalement des Ar-<lb/>chitectes; </s> <s xml:id="echoid-s3450" xml:space="preserve">mais, je n’ai pas voulu m’écarter de mon ſujet, ni trop <lb/>m’étendre ſur ce qui auroit pû me diſtraire des autres parties qui <lb/>doivent compoſer la ſuite de mon ouvrage.</s> <s xml:id="echoid-s3451" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3452" xml:space="preserve">Je ne dirai rien non plus de la maniere de déterminer la longueur <lb/>des contreforts par raport a leur épaiſſeur & </s> <s xml:id="echoid-s3453" xml:space="preserve">leur diſtance, parce <lb/>que je n’aurois pû le faire que par des opérations très compoſées; <lb/></s> <s xml:id="echoid-s3454" xml:space="preserve">mais comme on peut s’en paſſer, puiſque les perſonnes qui ſont dans <lb/>l’uſage de faire travailler ont ordinairement aſſés de connoiſſance <lb/>pour prendre d’eux-mêmes de juſtes meſures, les quatre propoſitions <lb/>précédentes leur ſuffiront.</s> <s xml:id="echoid-s3455" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div249" type="section" level="2" n="70"> <head xml:id="echoid-head196" xml:space="preserve">PROPOSITION CINQUIE’ME.</head> <head xml:id="echoid-head197" xml:space="preserve"><emph style="sc">Proble’me</emph>.</head> <p style="it"> <s xml:id="echoid-s3456" xml:space="preserve">Trouver l’épaiſſeur qu’il faut donner aux Culées des Ponts <lb/>de Maçonnerie pour ſoûtenir en équilibre la pouſſée des Arches.</s> <s xml:id="echoid-s3457" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3458" xml:space="preserve">59. </s> <s xml:id="echoid-s3459" xml:space="preserve">Voulant faire un Pont compoſé d’une Arche en plain-ceintre <lb/> <anchor type="note" xlink:label="note-0171-01a" xlink:href="note-0171-01"/> BDI, il faut élever ſur le ceintre A la perpendiculaire AG & </s> <s xml:id="echoid-s3460" xml:space="preserve">diviſer <lb/> <anchor type="note" xlink:label="note-0171-02a" xlink:href="note-0171-02"/> le quart de cercle BD en deux également par le raïon AF; </s> <s xml:id="echoid-s3461" xml:space="preserve">enſuite <lb/>mener la ligne MK paralelle à EA, enſorte qu’elle paſſe par le point <lb/>L milieu de l’épaiſſeur FC de l’Arche, & </s> <s xml:id="echoid-s3462" xml:space="preserve">alors elle déterminera la <lb/>hauteur la plus convenable qu’il faut donner à la Culée MPSQ. </s> <s xml:id="echoid-s3463" xml:space="preserve">Or <lb/>ſupoſant le raïon AB de 36 pieds, l’epaiſſeur FC ou GD de 6, & </s> <s xml:id="echoid-s3464" xml:space="preserve">la <lb/>hauteur BS de 12, on trouvera l’épaiſſeur PS de la Culée en faiſant <lb/>les quatre opérations ſuivantes.</s> <s xml:id="echoid-s3465" xml:space="preserve"/> </p> <div xml:id="echoid-div249" type="float" level="3" n="1"> <note position="right" xlink:label="note-0171-01" xlink:href="note-0171-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>6.</note> <note position="right" xlink:label="note-0171-02" xlink:href="note-0171-02a" xml:space="preserve"><emph style="sc">Fig</emph>. .6</note> </div> <p> <s xml:id="echoid-s3466" xml:space="preserve">Pour la premiere, il faut quarrer la ligne AL (de 39 pieds) pren-<lb/>dre la moitié du produit & </s> <s xml:id="echoid-s3467" xml:space="preserve">en extraire la racine (qu’on trouvera <lb/>de 27 pieds 7 pouces) pour avoir la valeur de chaque côté LV ou <lb/>VA du triangle rectangle LAV, & </s> <s xml:id="echoid-s3468" xml:space="preserve">l’on aura en même tems la <lb/>partie BV (de 8 pieds 5 pouces qu’il faut écrire à part, parce qu’on <lb/>en aura beſoin dans la troiſiéme opération,) enſuite ajoûter enſem-<lb/>ble les lignes LV & </s> <s xml:id="echoid-s3469" xml:space="preserve">BS, pour avoir la hauteur MP de la Culée de <lb/>39 pieds 7 pouces, qui ſera le premier terme.</s> <s xml:id="echoid-s3470" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3471" xml:space="preserve">Pour la ſeconde, il faut chercher la valeur des deux cercles des <lb/>raïons AD & </s> <s xml:id="echoid-s3472" xml:space="preserve">AG, (c’eſt-à-dire, de 36 & </s> <s xml:id="echoid-s3473" xml:space="preserve">de 42 pieds,) en prendre <lb/>la difference, & </s> <s xml:id="echoid-s3474" xml:space="preserve">la huitiéme partie de cette difference (qu’on trou- <pb o="64" file="0172" n="175" rhead="LA SCIENCE DES INGENIEURS."/> vera de 184 pieds quarrés,) qu’il faut diviſer par le premier terme <lb/>(j’entends par 39 pieds 7 pouces) & </s> <s xml:id="echoid-s3475" xml:space="preserve">le quotient donnera 4 pieds <lb/>7 pouces 9 lignes, pour le ſecond terme.</s> <s xml:id="echoid-s3476" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3477" xml:space="preserve">Pour la troiſiéme, il faut ſouſtraire la partie BV (de 8 pieds 5 <lb/>pouces qu’on a trouvé dans la premiere opération) du premier ter-<lb/>me (39 pieds 7 pouces,) la difference (31 pieds 2 pouces) <lb/>doubler & </s> <s xml:id="echoid-s3478" xml:space="preserve">l’on aura 62 pieds 4 pouces, pour le troiſiéme terme.</s> <s xml:id="echoid-s3479" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3480" xml:space="preserve">Enfin, pour la quatriéme, il faut ajoûter le ſecond terme (4 pieds <lb/>7 pouces 9 lignes,) au troiſiéme (62 pieds 4 pouces, pour avoir <lb/>66 pieds 11 pouces 9 lignes) qu’on multipliera par le ſecond terme, <lb/>& </s> <s xml:id="echoid-s3481" xml:space="preserve">extraire la racine quarrée du produit (311 pieds qu’on trouvera de <lb/>17 pieds 7 pouces 9 lignes,) de laquelle retranchant le ſecond <lb/>(4 pieds 7 pouces 9 lignes) la difference ſera 13 pieds, pour l’épaiſ-<lb/>ſeur de la Culée, & </s> <s xml:id="echoid-s3482" xml:space="preserve">ſi on l’augmente d’une ſixiéme, ſuivant la Remar-<lb/>que précédente, il faudra lui douner 15 pieds 2 pouces pour mieux <lb/>ſoûtenir le poids de la Chauſſée du Pont & </s> <s xml:id="echoid-s3483" xml:space="preserve">les Voitures qui paſſe-<lb/>ront deſſus.</s> <s xml:id="echoid-s3484" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div251" type="section" level="2" n="71"> <head xml:id="echoid-head198" style="it" xml:space="preserve">Remarque.</head> <p> <s xml:id="echoid-s3485" xml:space="preserve">Quoique les calculs précédens ſoient bien aiſés, j’en aurois vo-<lb/>lontiers diſpenſé ceux qui n’en ont pas l’habitude, ſi j’avois pû donner <lb/>des Tables pour trouver l’épaiſſeur des piés-droits des Voûtes dans <lb/>toute ſorte de cas; </s> <s xml:id="echoid-s3486" xml:space="preserve">mais, c’eſt ce qui ne m’a pas parû poſſible, à cauſe <lb/>que les Edifices où on les employe ſont ſujets à une infinité de cir-<lb/>conſtances differentes, ſoit de la part de leur figure, ou de leur <lb/>ſolidité, ſelon les uſages auxquels on les deſtine: </s> <s xml:id="echoid-s3487" xml:space="preserve">& </s> <s xml:id="echoid-s3488" xml:space="preserve">ſi l’on ſavoit ce <lb/>qu’il m’en a coûté pour reduire la Théorie aux Pratiques que je viens <lb/>d’enſeigner, l’on conviendroit que tout bien conſideré on n’a pas lieu <lb/>d’être mécontent de moi, puiſque j’ai fait tout ce qui étoit en mon <lb/>pouvoir pour m’accommoder aux differens genies de mes Lecteurs, <lb/>comme on s’en apercevra encore mieux dans la ſuite.</s> <s xml:id="echoid-s3489" xml:space="preserve"/> </p> <figure> <image file="0172-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0172-01"/> </figure> <pb file="0173" n="176"/> <pb file="0173a" n="177"/> <figure> <image file="0173a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0173a-01"/> </figure> <pb file="0174" n="178"/> <pb file="0175" n="179"/> <pb file="0175a" n="180"/> <figure> <image file="0175a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0175a-01"/> </figure> <pb file="0176" n="181"/> <pb file="0177" n="182"/> <pb file="0177a" n="183"/> <figure> <image file="0177a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0177a-01"/> </figure> <pb file="0178" n="184"/> <pb file="0179" n="185"/> </div> <div xml:id="echoid-div252" type="section" level="2" n="72"> <head xml:id="echoid-head199" xml:space="preserve">LA SCIENCE <lb/>DES INGENIEURS <lb/>DANS LA CONDUITE DES TRAVAUX <lb/>DE FORTIFICATION.</head> <head xml:id="echoid-head200" xml:space="preserve">LIVRE TROISIE’ME.</head> <p style="it"> <s xml:id="echoid-s3490" xml:space="preserve">Qui comprend la connoiſſance des Materiaux, leur propriété, <lb/>leur détail, & </s> <s xml:id="echoid-s3491" xml:space="preserve">la maniere de les mettre en œuvre.</s> <s xml:id="echoid-s3492" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3493" xml:space="preserve"><emph style="sc">AVant</emph> de parler de la Conſtruction des Ouvrages <lb/>de Fortification, qui vont faire le principal objet <lb/>de ce Livre, il eſt à propos de donner la connoiſ-<lb/>ſance des matériaux néceſſaires à leur execution, <lb/>afin qu’on en ſache diſtinguer les bonnes & </s> <s xml:id="echoid-s3494" xml:space="preserve">mau-<lb/>vaiſes qualitez. </s> <s xml:id="echoid-s3495" xml:space="preserve">Il y a un enchaînement de détails <lb/>qui font la principale partie de l’Art de bâtir, & </s> <s xml:id="echoid-s3496" xml:space="preserve">qu’on ſe pro-<lb/>poſe de bien déveloper ici: </s> <s xml:id="echoid-s3497" xml:space="preserve">ils paroîtront peut-être groſſiers & </s> <s xml:id="echoid-s3498" xml:space="preserve">peu <lb/>importans à ceux qui n’ont jamais fait travailler; </s> <s xml:id="echoid-s3499" xml:space="preserve">cependant, ſi l’on <lb/>fait réflexion que pour executer un projet, il faut dreſſer des Devis <pb o="2" file="0180" n="186" rhead="LA SCIENCE DES INGENIEURS,"/> qui expliquent les qualitez des matériaux dont il faudra ſe ſervir, <lb/>& </s> <s xml:id="echoid-s3500" xml:space="preserve">la maniere de les employer, l’on verra la neceſſité d’être bien <lb/>inſtruit des ſujets qui font l’objet des Chapitres ſuivans.</s> <s xml:id="echoid-s3501" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div253" type="section" level="2" n="73"> <head xml:id="echoid-head201" xml:space="preserve">CHAPITRE PREMIER.</head> <head xml:id="echoid-head202" style="it" xml:space="preserve">Où l’on fait voir les proprietez des differentes ſortes de Pier-<lb/>res dont on ſe ſert pour bâtir.</head> <p> <s xml:id="echoid-s3502" xml:space="preserve">LA Pierre tenant le premier rang parmi les matériaux que nous <lb/>nous propoſons de décrire, il convient de commencer par en <lb/>expliquer la nature, on en diſtingue de deux qualitez differentes, <lb/>l’une dure & </s> <s xml:id="echoid-s3503" xml:space="preserve">l’autre tendre, celle qui eſt dure eſt ſans difficulté la <lb/>meilleure, il s’en rencontre pourtant quelquefois de tendre qui ré-<lb/>ſiſte mieux à la gelée que l’autre; </s> <s xml:id="echoid-s3504" xml:space="preserve">mais comme cela n’eſt pas ordi-<lb/>naire, on ne doit pasy compter; </s> <s xml:id="echoid-s3505" xml:space="preserve">car comme les parties de la Pierre du-<lb/>re ont leur pores plus condenſez que celles de la tendre, elles doivent <lb/>être capables d’une plus grande réſiſtance, ſoit aux injures du tems, <lb/>ou au courant des Eaux dans les Edifices aquatiques: </s> <s xml:id="echoid-s3506" xml:space="preserve">mais, pour <lb/>bien connoître la nature de la Pierre, il eſt à propos de rendre rai-<lb/>ſon pourquoi celle qui eſt dure, auſſi-bien que la tendre, eſt ſujette <lb/>à la gelée qui la fend & </s> <s xml:id="echoid-s3507" xml:space="preserve">la fait tomber par éclat.</s> <s xml:id="echoid-s3508" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3509" xml:space="preserve">Dans l’aſſemblage des parties qui compoſent la Pierre, il y a des <lb/>pores imperceptibles remplis d’eau & </s> <s xml:id="echoid-s3510" xml:space="preserve">d’humidité, qui, venant à <lb/>s’enfler dans le tems des gelées, fait effort dans ces pores pour <lb/>occuper un plus grand eſpace que celui où elle eſt reſſerrée, & </s> <s xml:id="echoid-s3511" xml:space="preserve">la <lb/>Pierre ne pouvant reſiſter à cet effort, ſe fend & </s> <s xml:id="echoid-s3512" xml:space="preserve">tombe en deſ-<lb/>truction; </s> <s xml:id="echoid-s3513" xml:space="preserve">ainſi plus la Pierre eſt compoſée de parties argilleuſes <lb/>& </s> <s xml:id="echoid-s3514" xml:space="preserve">graſſes, & </s> <s xml:id="echoid-s3515" xml:space="preserve">plus elle doit participer de l’humidité, & </s> <s xml:id="echoid-s3516" xml:space="preserve">par conſé-<lb/>quent être ſujette à la gelée.</s> <s xml:id="echoid-s3517" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3518" xml:space="preserve">Ce n’eſt pas ſeulement la gelée qui détruit la Pierre, on croît <lb/>que la Lune l’altere, ce qui peut arriver pour les Pierres d’une <lb/>certaine eſpece, dont les rayons de la Lune peuvent diſſoudre les <lb/>parties les moins compactes: </s> <s xml:id="echoid-s3519" xml:space="preserve">en ce cas, on pourroit croire que ces <lb/>rayons ſont humides, & </s> <s xml:id="echoid-s3520" xml:space="preserve">que venant à s’introduire dansles pores de la <lb/>Pierre, ils ſont cauſe de la ſéparation de ces parties, qui tombant <lb/>inſenſiblement en parcelles, la fait paroître moulinée: </s> <s xml:id="echoid-s3521" xml:space="preserve">il en ſera au <lb/>reſte tout ce que l’on voudra; </s> <s xml:id="echoid-s3522" xml:space="preserve">mais, ce qui me réjoüit, c’eſt que <lb/>ſi la Lune mange ou mouline les Pierres, la Terre qui doit être une <pb o="3" file="0181" n="187" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> bien plus grande Lune, a bien ſa revanche, & </s> <s xml:id="echoid-s3523" xml:space="preserve">les Pierres de la haut <lb/>ſans doute n’ont pas beau jeu.</s> <s xml:id="echoid-s3524" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3525" xml:space="preserve">Dans les endroits où l’on ſe propoſe de bâtir, on pourra juger <lb/>de la qualité de la Pierre des Carrieres des environs, par l’examen <lb/>de celle dont on aura conſtruit quelques anciens édifices; </s> <s xml:id="echoid-s3526" xml:space="preserve">mais ſi <lb/>l’on vouloit en employer d’une nouvelle Carriere, dont on n’eût <lb/>pas encore fait uſage, il faudroit en prendre quelques quartiers, tirez <lb/>de differens endroits de la Carriere, qu’on expoſera ſur une terre <lb/>humide, pour lui laiſſer eſſuyer la gelée d’une partie de l’hyver, & </s> <s xml:id="echoid-s3527" xml:space="preserve"><lb/>s’ils réſiſtent dans cette ſituation, on pourra s’aſſurer qu’elle eſt <lb/>bonne; </s> <s xml:id="echoid-s3528" xml:space="preserve">on peut encore avoir recours à diverſes obſervations, pour <lb/>connoître ſi elle eſt d’un bon uſage, par exemple on ſe méfiera de <lb/>celles qui ſont de couleur d’un jaune foncé, parce que ſouvent <lb/>cette couleur ne vient qu’à cauſe que la Pierre eſt graſſe, ou n’a <lb/>pas encore jetté ſon eau de Carriere; </s> <s xml:id="echoid-s3529" xml:space="preserve">de celles où l’on apercevra <lb/>des veines brunes ou rouges, & </s> <s xml:id="echoid-s3530" xml:space="preserve">qui ont une groſſeur conſidérable <lb/>de bouzin ou dont les parties ne ſont pas aſſez ſerrées pour réſiſter <lb/>aux empreintes qu’on voudroit faire deſſus en les frapant avec une <lb/>baguette, de celles qui ſont ſi graſſes qu’elles paroiſſent mouliner & </s> <s xml:id="echoid-s3531" xml:space="preserve"><lb/>qui s’écaillent trop facilement & </s> <s xml:id="echoid-s3532" xml:space="preserve">ſe réduiſent en feüille, dès qu’on <lb/>les frape avec le marteau; </s> <s xml:id="echoid-s3533" xml:space="preserve">de celles enfin qui ſont trop fraiſche-<lb/>ment tirées des Carrieres & </s> <s xml:id="echoid-s3534" xml:space="preserve">qu’on ne peut gueres employer ſeu-<lb/>rement quand même elles n’auroient pas les deffauts que nous ve-<lb/>nons de remarquer, qu’après les avoir expoſées un hyver à la ge-<lb/>lée. </s> <s xml:id="echoid-s3535" xml:space="preserve">Mais ſi l’on eſt preſſé il faudra au moins les mettre en œuvre <lb/>à la fin du Printems, afin que les chaleurs de l’Eté faſſent évaporer <lb/>l’humidité qu’elles renferment pour être enſuite à l’épreuve des <lb/>plus rudes ſaiſons.</s> <s xml:id="echoid-s3536" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3537" xml:space="preserve">On jugera de la bonté de la Pierre, ſi elle eſt bien pleine, d’une <lb/>couleur égale, ſans veine, d’un grain fin & </s> <s xml:id="echoid-s3538" xml:space="preserve">uni, ſi les éclats s’y <lb/>coupent net & </s> <s xml:id="echoid-s3539" xml:space="preserve">rendent quelque ſon.</s> <s xml:id="echoid-s3540" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3541" xml:space="preserve">Quand on employe la Pierre, il faut faire enſorte de la poſer ſur <lb/>ſon lit, je veux dire de la même façon qu’elle étoit placée dans la <lb/>Carriere, parce que ſelon cette ſituation elle eſt capable de reſiſ-<lb/>ter autant qu’il lui eſt poſſible au poids des gros fardeaux dont elle <lb/>ſera chargée, au lieu que poſée d’un autre ſens elle s’éclate & </s> <s xml:id="echoid-s3542" xml:space="preserve"><lb/>n’a pas à beaucoup près autant de force; </s> <s xml:id="echoid-s3543" xml:space="preserve">la plupart des bons Ou-<lb/>vriers connoiſſent d’un coup d’œil le lit de la Pierre; </s> <s xml:id="echoid-s3544" xml:space="preserve">mais, à moins <lb/>qu’on n’y prenne garde, ils ne s’aſujettiſſent pas toûjours à la poſer <lb/>comme il faut.</s> <s xml:id="echoid-s3545" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3546" xml:space="preserve">Quand on conſtruit quelque Edifice, où on eſt obligé de ſe ſer- <pb o="4" file="0182" n="188" rhead="LA SCIENCE DES INGENIEURS,"/> vir de Pierres de differente qualité, il faut prendre garde d’em-<lb/>ployer la meilleure, la plus dure, & </s> <s xml:id="echoid-s3547" xml:space="preserve">celle qui reſiſte le mieux à la <lb/>gelée, aux endroits qui ſont expoſez à l’air, reſervant celle qu’on <lb/>ſoupçonnera n’être pas ſi bonne, pour les placer dans les fondemens <lb/>& </s> <s xml:id="echoid-s3548" xml:space="preserve">aux endroits couverts.</s> <s xml:id="echoid-s3549" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3550" xml:space="preserve">Dans les Carrieres la Pierre s’y trouve ordinairement diſpoſée par <lb/>bancs, dont l’épaiſſeur change ſelon les lieux & </s> <s xml:id="echoid-s3551" xml:space="preserve">la nature de la Pierre; <lb/></s> <s xml:id="echoid-s3552" xml:space="preserve">par exemple, celle d’Arcuëil proche Paris porte depuis douze juſ-<lb/>qu’à quinze pouces de banc. </s> <s xml:id="echoid-s3553" xml:space="preserve">Il y a d’autres Carrieres aux environs <lb/>de la même Ville, dont les bancs ont juſqu’à deux pieds & </s> <s xml:id="echoid-s3554" xml:space="preserve">demi, <lb/>& </s> <s xml:id="echoid-s3555" xml:space="preserve">trois pieds; </s> <s xml:id="echoid-s3556" xml:space="preserve">mais ſans nous arreſter davantage là-deſſus, il ſuffit de <lb/>dire que quand on fait bâtir dans un Pays, où l’on n’a point une <lb/>parfaite connoiſſance de toutes ces particularitez, il faudra s’en inſ-<lb/>truire ſur les lieux, afin de pouvoir circonſtancier, dans le Devis, <lb/>de quelle Carriere les Pierres devront être tirées, afin qu’elles <lb/>conviennent à l’Ouvrage que l’on a deſſein d’executer.</s> <s xml:id="echoid-s3557" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3558" xml:space="preserve">Quand la Pierre, que l’on veut mettre en œuvre, eſt compoſée <lb/>d’aſſez gros quartiers, pour être taillée de telle figure que l’on veut, <lb/>on la nomme Pierre de taille: </s> <s xml:id="echoid-s3559" xml:space="preserve">à l’égard de celle dont on ne fait qu’ô-<lb/>ter le bouſin, & </s> <s xml:id="echoid-s3560" xml:space="preserve">qu’on équarit groſſierement pour être employée <lb/>au rempliſſage des gros murs, & </s> <s xml:id="echoid-s3561" xml:space="preserve">dans les fondemens, on l’appelle <lb/>moîlon, que l’on tire des Carrieres, dont les bancs n’ont pas aſſez <lb/>de hauteur pour pouvoir être taillées & </s> <s xml:id="echoid-s3562" xml:space="preserve">employées au parement.</s> <s xml:id="echoid-s3563" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3564" xml:space="preserve">Il s’employe aux environs de Paris un moîlon qu’on nomme Pierre <lb/>de Meuliere, qui eſt fort dure & </s> <s xml:id="echoid-s3565" xml:space="preserve">fort poreuſe, & </s> <s xml:id="echoid-s3566" xml:space="preserve">qui fait une Maçon-<lb/>nerie excellente, parce que le mortier s’y attache mieux qu’à toute <lb/>autre ſorte de Pierres; </s> <s xml:id="echoid-s3567" xml:space="preserve">& </s> <s xml:id="echoid-s3568" xml:space="preserve">c’eſt par cette raiſon que la Brique, quand <lb/>elle eſt bonne, vaut mieux pour l’union de la Maçonnerie, que la <lb/>plûpart des Pierres dures, parce que le mortier s’inſinuë dans ſes <lb/>pores & </s> <s xml:id="echoid-s3569" xml:space="preserve">s’y attache fortement.</s> <s xml:id="echoid-s3570" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3571" xml:space="preserve">On ſe ſert encore pour les fondemens d’une autre eſpece de Pierre <lb/>plus dure que le moîlon, qu’on nomme libage: </s> <s xml:id="echoid-s3572" xml:space="preserve">elle ſe tire du ciel <lb/>des Carrieres; </s> <s xml:id="echoid-s3573" xml:space="preserve">on l’employe brute, ne pouvant être taillée propre-<lb/>ment, à cauſe quelle eſt toûjours d’une forme irréguliere.</s> <s xml:id="echoid-s3574" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3575" xml:space="preserve">Le Grès, qui eſt un eſpece de Roche, ſe trouve preſque toûjours <lb/>à découvert, & </s> <s xml:id="echoid-s3576" xml:space="preserve">c’eſt ce qui contribuë à ſa dureté; </s> <s xml:id="echoid-s3577" xml:space="preserve">car en general <lb/>toutes les Pierres qu’on trouve ſans creuſer beaucoup en terre <lb/>ſont plus ſolides que celles que l’on tire du fond des Carrieres; <lb/></s> <s xml:id="echoid-s3578" xml:space="preserve">& </s> <s xml:id="echoid-s3579" xml:space="preserve">c’eſt à quoi les Anciens s’attachoient beaucoup, puiſque, pour <lb/>rendre leurs Edifices d’une plus longue durée, ils ſe ſervoient de <lb/>Pierres provenant des entamures des Carrieres qu’on découvroit;</s> <s xml:id="echoid-s3580" xml:space="preserve"> <pb o="5" file="0183" n="189" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> on diſtingue de deux ſortes de Grès, le dur & </s> <s xml:id="echoid-s3581" xml:space="preserve">le tendre; </s> <s xml:id="echoid-s3582" xml:space="preserve">le dur <lb/>n’eſt bon que pour paver les ruës & </s> <s xml:id="echoid-s3583" xml:space="preserve">les grands chemins, le tendre <lb/>ſe coupe & </s> <s xml:id="echoid-s3584" xml:space="preserve">ſe débite comme les Pierres ordinaires, on l’employe <lb/>au ſoubaſſement des gros murs, principalement pour ceux qui ſont <lb/>baignez des eaux, ſon deffaut eſt de ne pas faire une bonne liaiſon <lb/>c’eſt pourquoi on fait des hachures dans les joints pour que le mor-<lb/>tier s’y acroche mieux, ces joints ſe rempliſſent en dehors avec <lb/>du ciment, parce qu’il s’attache mieux à la Pierre dure que le mor-<lb/>tier ordinaire.</s> <s xml:id="echoid-s3585" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div254" type="section" level="2" n="74"> <head xml:id="echoid-head203" xml:space="preserve">CHAPITRE DEUXIE’ME.</head> <head xml:id="echoid-head204" style="it" xml:space="preserve">Où l’on conſidere les qualitez de la Brique & la maniere <lb/>de la fabriquer.</head> <p> <s xml:id="echoid-s3586" xml:space="preserve">LA Brique étant une eſpece de Pierre artificielle, dont l’uſage <lb/>eſt trés fréquent dans les Conſtructions des Edifices, particu-<lb/>lierement pour les Fortifications, nous en allons faire le détail, <lb/>qui, quoique groſſier en apparence, ne laiſſe pas d’être utile à ſavoir, <lb/>à ceux qui ont la conduite des travaux, pour qui les moindres cho-<lb/>ſes ne doivent pas être indifferentes, quand elles peuvent contri-<lb/>buer à la perfection de leur métier.</s> <s xml:id="echoid-s3587" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3588" xml:space="preserve">Pour bien choiſir une terre propre à faire de la Brique, il faut <lb/>qu’elle ſoit graſſe & </s> <s xml:id="echoid-s3589" xml:space="preserve">forte, de couleur blanchâtre, ou grisâtre, <lb/>ſans qu’il s’y rencontre de petits cailloux ni gravier; </s> <s xml:id="echoid-s3590" xml:space="preserve">il y en a auſſi <lb/>de la rouge qui peut ſervir au même uſage; </s> <s xml:id="echoid-s3591" xml:space="preserve">mais elle n’eſt pas des <lb/>meilleures, parce que les Briques ſont ſujettes à ſe feüilleter & </s> <s xml:id="echoid-s3592" xml:space="preserve">à <lb/>ſe réduire en poudre à la gelée; </s> <s xml:id="echoid-s3593" xml:space="preserve">mais ſans prendre garde ſcrupuleu-<lb/>ſement à la couleur, on jugera qu’une terre eſt bonne pour faire <lb/>de la Brique, ſi, après une petite pluye, on s’aperçoit qu’en mar-<lb/>chant deſſus elle s’attache aux ſouliers, & </s> <s xml:id="echoid-s3594" xml:space="preserve">s’y amaſſe en groſſe quan-<lb/>tité, ſans qu’elle s’en détache aiſément; </s> <s xml:id="echoid-s3595" xml:space="preserve">ou ſi, en ayant pétri dans <lb/>les mains, on ne peut la diviſer qu’avec peine.</s> <s xml:id="echoid-s3596" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3597" xml:space="preserve">Après avoir choiſi un eſpace de terre convenable, on la fait <lb/>foüiller avec la houë, & </s> <s xml:id="echoid-s3598" xml:space="preserve">ayant reconnu qu’elle eſt également bonne <lb/>par-tout, on attend le tems de la pluye, parce qu’en étant bien <lb/>imbibée, on la corroye enſuite avec la houë & </s> <s xml:id="echoid-s3599" xml:space="preserve">le rabot, après <lb/>quoi on la laiſſe repoſer pendant quelque tems, au bout duquel <lb/>on recommence la même choſe, ce que l’on fait quatre ou cinq <pb o="6" file="0184" n="190" rhead="LA SCIENCE DES INGENIEURS,"/> fois à diverſes repriſes: </s> <s xml:id="echoid-s3600" xml:space="preserve">on commence ordinairement la prépara-<lb/>tion des terres dans le mois de Mars; </s> <s xml:id="echoid-s3601" xml:space="preserve">mais il vaudroit mieux la <lb/>faire dans l’hyver, parce que les petites gelées ſont excellentes <lb/>pour les bien corroyer: </s> <s xml:id="echoid-s3602" xml:space="preserve">le veritable tems pour faire la Brique eſt <lb/>pendant les mois de May & </s> <s xml:id="echoid-s3603" xml:space="preserve">de Juin, parce que dans cette ſaiſon <lb/>elle a tout le tems de ſeicher, pour être enſuite plus propre à met-<lb/>tre au Four; </s> <s xml:id="echoid-s3604" xml:space="preserve">car il faut autant qu’il ſe peut éviter la ſaiſon trop <lb/>avancée, les Briques faites alors n’étant pas ſi bonnes à beaucoup <lb/>près que celles qui ſont faites en Eté.</s> <s xml:id="echoid-s3605" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3606" xml:space="preserve">Ce n’eſt pas aſſez d’avoir inſinué ce qui peut contribuer à faire <lb/>de bonnes Briques, il faut encore diſcerner les bonnes & </s> <s xml:id="echoid-s3607" xml:space="preserve">mau-<lb/>vaiſes qualitez de celles qui ſe trouvent en Magaſin, puiſque c’eſt <lb/>de-là que dépend la durée de l’ouvrage qu’on veut éxécuter. </s> <s xml:id="echoid-s3608" xml:space="preserve">Vitruve <lb/>raporte que de ſon tems, dans la fameuſe Ville d’Utique, le Ma-<lb/>giſtrat, pour empêcher toute male-façon, ne permettoit pas qu’on <lb/>en employât pour aucun Edifice, qu’il ne les eût viſitées aupara-<lb/>vant & </s> <s xml:id="echoid-s3609" xml:space="preserve">donné ſon approbation: </s> <s xml:id="echoid-s3610" xml:space="preserve">on s’aperçoit bien que cette ſage <lb/>police n’eſt plus d’uſage parmi nous, puiſqu’à la confuſion de la <lb/>plûpart des Entrepreneurs, l’on voit tous les jours des Bàtimens <lb/>menacer ruine, avant pour ainſi dire d’être achevez.</s> <s xml:id="echoid-s3611" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3612" xml:space="preserve">La Brique, qui eſt d’une couleur jaune, aprochant un peu d’un <lb/>rouge pâle, eſt bonne, parce qu’ordinairement elle a été faite d’une <lb/>terre graſſe, comme eſt celle dont nous venons de parler. </s> <s xml:id="echoid-s3613" xml:space="preserve">On con-<lb/>noîtra encore la bonne Brique au ſon, car celle dont il ſera le plus <lb/>net ſera préférable aux autres dont le ſon eſt ſourd. </s> <s xml:id="echoid-s3614" xml:space="preserve">Il arrive aſſez <lb/>ſouvent que des Briques faites d’une bonne terre, & </s> <s xml:id="echoid-s3615" xml:space="preserve">préparées <lb/>également, ſont de differentes couleurs, & </s> <s xml:id="echoid-s3616" xml:space="preserve">par conſéquent de dif-<lb/>ferentes qualitez, & </s> <s xml:id="echoid-s3617" xml:space="preserve">cela ſe diſtingue ſur-tout quand on en voit qui <lb/>ſont plus rouges les unes que les autres, qui n’en ſont pas pour cela <lb/>meilleures, mais au contraire, puiſqu’elles ſont d’une très-mauvaiſe <lb/>qualité, parce qu’elles ont été placées dans le Four à des endroits <lb/>où le feu n’a pas eû aſſez de force pour les cuire, ce qui fait qu’elles <lb/>ne réſiſtent pas à la gelée ni au poids dont elles ſont chargées, ſe <lb/>caſſant & </s> <s xml:id="echoid-s3618" xml:space="preserve">ſe réduiſant en poudre facilement.</s> <s xml:id="echoid-s3619" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3620" xml:space="preserve">Enfin, la preuve la plus ſûre pour connoître la bonté de la Bri-<lb/>que, quand il s’agit de quelque Ouvrage d’importance, dont on peut <lb/>differer l’execution d’une année, c’eſt de coucher celles que l’on <lb/>veut employer, ſur la terre pendant l’hyver, pour y eſſuyer la gelée, <lb/>parce qu’alors celles qui y auront réſiſté ſans ſe feüilleter, & </s> <s xml:id="echoid-s3621" xml:space="preserve">auſ-<lb/>quelles il ne ſera arrivé aucune alteration conſiderable, pourront <lb/>être miſes en œuvre en toute ſureté.</s> <s xml:id="echoid-s3622" xml:space="preserve"/> </p> <pb o="7" file="0185" n="191" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> <p> <s xml:id="echoid-s3623" xml:space="preserve">La grandeur ordinaire des Briques eſt 8 ou 9 pouces de lon-<lb/>gueur ſur 4 ou 5 & </s> <s xml:id="echoid-s3624" xml:space="preserve">demi de largeur & </s> <s xml:id="echoid-s3625" xml:space="preserve">2 d’épaiſſeur; </s> <s xml:id="echoid-s3626" xml:space="preserve">ces dimen-<lb/>ſions ſont le plus en uſage, parce qu’elles rendent les Briques fort <lb/>commodes pour être miſes en œuvre.</s> <s xml:id="echoid-s3627" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3628" xml:space="preserve">Quand les Murs n’ont qu’une médiocre épaiſſeur, on les déter-<lb/>mine par le nombre des Briques qu’il faut pour en marquer l’é-<lb/>tendue, tels ſont ceux de deux Briques, d’une Brique & </s> <s xml:id="echoid-s3629" xml:space="preserve">demi, & </s> <s xml:id="echoid-s3630" xml:space="preserve"><lb/>d’une Brique, dont on ſe ſert pour les Murs mitoyens, ou pour <lb/>ceux de clôture.</s> <s xml:id="echoid-s3631" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div255" type="section" level="2" n="75"> <head xml:id="echoid-head205" xml:space="preserve">CHAPITRE TROISIE’ME.</head> <head xml:id="echoid-head206" style="it" xml:space="preserve">Où l’on fait voir les qualitez de la Chaux & la maniere <lb/>de l’éteindre.</head> <p> <s xml:id="echoid-s3632" xml:space="preserve">LA Chaux pouvant être regardée comme l’Ame de la Maçonne-<lb/>rie, il eſt de la derniere conſéquence d’être bien inſtruit de <lb/>tout ce qui lui apartient, afin que dans l’uſage que l’on en fera, <lb/>on parvienne à cette fin principale que l’on doit ſe propoſer en <lb/>conſtruiſant les Bâtimens, qui eſt de faire enſorte que les maté-<lb/>riaux ſoient ſi bien unis qu’ils ne paroiſſent plus compoſer qu’une <lb/>ſeule Pierre.</s> <s xml:id="echoid-s3633" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3634" xml:space="preserve">La Chaux eſt une Pierre calcinée, qui ſe détrempe avec de l’eau <lb/>& </s> <s xml:id="echoid-s3635" xml:space="preserve">du ſable, pour en compoſer le mortier: </s> <s xml:id="echoid-s3636" xml:space="preserve">pour faire de la bonne <lb/>Chaux, il faut ſe ſervir de pierres très-dures, peſantes, & </s> <s xml:id="echoid-s3637" xml:space="preserve">blanches; <lb/></s> <s xml:id="echoid-s3638" xml:space="preserve">& </s> <s xml:id="echoid-s3639" xml:space="preserve">de toutes celles qu’on peut employer, il n’y en a point qui en <lb/>faſſe de meilleure que le marbre, quand on eſt à portée d’en avoir <lb/>comme dans le Pays où il eſt commun: </s> <s xml:id="echoid-s3640" xml:space="preserve">la Pierre tirée de frais ou <lb/>nouvellement eſt meilleure à faire la Chaux, que la ramaſſée; </s> <s xml:id="echoid-s3641" xml:space="preserve">& </s> <s xml:id="echoid-s3642" xml:space="preserve">par-<lb/>ticulierement celle des Carrieres humides & </s> <s xml:id="echoid-s3643" xml:space="preserve">à l’ombre, que celles <lb/>qui ſont plus ſeiches: </s> <s xml:id="echoid-s3644" xml:space="preserve">les Cailloux qui ſe rencontrent ſur les Mon-<lb/>tagnes, ou dans les Rivieres & </s> <s xml:id="echoid-s3645" xml:space="preserve">les Torrens, auſſi-bien que certai-<lb/>nes Pierres ſpongieuſes & </s> <s xml:id="echoid-s3646" xml:space="preserve">dures qui ſe trouvent quelques fois dans <lb/>les Campagnes, font une très-bonne Chaux, & </s> <s xml:id="echoid-s3647" xml:space="preserve">l’ouvrage en eſt fort <lb/>blanc & </s> <s xml:id="echoid-s3648" xml:space="preserve">poli; </s> <s xml:id="echoid-s3649" xml:space="preserve">ce qui fait qu’on s’en ſert ordinairement au crépiſ-<lb/>ſage des Murs: </s> <s xml:id="echoid-s3650" xml:space="preserve">il y a une Pierre jaunâtre, qui ſe tire aux environs <lb/>de Boulogne en France, qui fait auſſi une Chaux excellente, & </s> <s xml:id="echoid-s3651" xml:space="preserve">qui <lb/>eſt la plus eſtimée de toutes celles qu’on peut employer en Picardie <lb/>& </s> <s xml:id="echoid-s3652" xml:space="preserve">en Artois, où communement elle n’eſt pas trop bonne, parce <lb/>qu’on la fait avec du moîlon tendre & </s> <s xml:id="echoid-s3653" xml:space="preserve">blanc, qui ne differe gueres <pb o="8" file="0186" n="192" rhead="LA SCIENCE DES INGENIEURS,"/> de la craye, qui eſt la plus mauvaiſe qualité qu’une Pierre puiſſe <lb/>avoir pour faire de la Chaux.</s> <s xml:id="echoid-s3654" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3655" xml:space="preserve">Le Charbon de terre vaut beaucoup mieux pour cuire la Chaux <lb/>que le bois; </s> <s xml:id="echoid-s3656" xml:space="preserve">car, non-ſeulement la cuiſſon en eſt plus prompte, <lb/>mais c’eſt qu’il rend la Chaux plus graſſe & </s> <s xml:id="echoid-s3657" xml:space="preserve">plus onctueuſe.</s> <s xml:id="echoid-s3658" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3659" xml:space="preserve">Quand la Chaux eſt tirée du Fourneau, il faut pour la bien <lb/>éteindre prendre garde que les Ouvriers y mettent la quantité <lb/>d’eau néceſſaire, car le trop peu la brûle, & </s> <s xml:id="echoid-s3660" xml:space="preserve">la trop grande quan-<lb/>tité la noye, le mieux eſt de la jetter à diverſes repriſes.</s> <s xml:id="echoid-s3661" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3662" xml:space="preserve">L’on connoît, ſelon Philbert de Lorme, quela Chaux eſt bonne, <lb/>lorſqu’elle eſt bien cuite, blanche, & </s> <s xml:id="echoid-s3663" xml:space="preserve">graſſe, qu’elle n’eſt pas éventée <lb/>& </s> <s xml:id="echoid-s3664" xml:space="preserve">ſonne comme un pot de terre quand on la frape, qu’étant <lb/>moüillée ſa fumée paroît épaiſſe, & </s> <s xml:id="echoid-s3665" xml:space="preserve">lorſqu’en la détrempant elle ſe <lb/>lie au rabot.</s> <s xml:id="echoid-s3666" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3667" xml:space="preserve">Selon ce même Architecte, la maniere de la bien détremper <lb/>pour faire d’excellent mortier, eſt d’en amaſſer dans une Foſſe telle <lb/>quantité qu’on en aura beſoin, puis la couvrir également par-tout <lb/>de bon ſable environ un pied ou deux d’épaiſſeur, enſuite jetter <lb/>de l’eau par deſſus ſuffiſamment pour faire que le ſable en ſoit bien <lb/>abreuvé, afin que la Chaux qui eſt deſſous ſe puiſſe fuſer & </s> <s xml:id="echoid-s3668" xml:space="preserve">diſſou-<lb/>dre ſans ſe brûler, ce qui arriveroit ſi on ne lui donnoit pas d’eau <lb/>ſuffiſamment; </s> <s xml:id="echoid-s3669" xml:space="preserve">ſi l’on s’aperçoit que le ſable ſe fende en quelqu’en-<lb/>droit, & </s> <s xml:id="echoid-s3670" xml:space="preserve">faſſe paſſage à la fumée, il faut auſſi-tôt recouvrir les <lb/>crevaſſes, & </s> <s xml:id="echoid-s3671" xml:space="preserve">moyennant cette préparation, elle ſe convertira en <lb/>une maſſe de graiſſe, laquelle étant entamée au bout de deux ou <lb/>trois ans reſſemblera à un fromage de crême; </s> <s xml:id="echoid-s3672" xml:space="preserve">cette matiere ſera <lb/>ſi graſſe & </s> <s xml:id="echoid-s3673" xml:space="preserve">ſi glutineuſe, qu’on n’en pourra tirer le rabot qu’avec <lb/>peine, & </s> <s xml:id="echoid-s3674" xml:space="preserve">fera un mortier d’un excellent uſage pour les enduits <lb/>des murailles & </s> <s xml:id="echoid-s3675" xml:space="preserve">les Ouvrages de Stuc.</s> <s xml:id="echoid-s3676" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3677" xml:space="preserve">Vitruve remarque, qu’il eſt néceſſaire que les Pierres de Chaux <lb/>foient éteintes depuis long-tems, afin que s’il y a quelques mor-<lb/>ceaux qui ayent été moins cuits que les autres, ils puiſſent étant <lb/>éteints à loiſir ſe détremper auſſi aiſément que les autres; </s> <s xml:id="echoid-s3678" xml:space="preserve">car dans <lb/>la Chaux qui eſt employéeen ſortant du Fourneau, & </s> <s xml:id="echoid-s3679" xml:space="preserve">devant qu’elle <lb/>ſoit parfaitement éteinte, il reſte quantité de petites Pierres moins <lb/>cuites qui font ſur l’ouvrage comme des puſtules; </s> <s xml:id="echoid-s3680" xml:space="preserve">parce que ve-<lb/>nant à s’éteindre plus tard que le reſte de la Chaux, elles rompent <lb/>l’enduit & </s> <s xml:id="echoid-s3681" xml:space="preserve">le gâtent; </s> <s xml:id="echoid-s3682" xml:space="preserve">il ajoûte auſſi que pour ſavoir ſi la Chaux eſt <lb/>bien éteinte & </s> <s xml:id="echoid-s3683" xml:space="preserve">ſuffiſamment détrempée, il faut y enfoncer un coû-<lb/>teau: </s> <s xml:id="echoid-s3684" xml:space="preserve">s’il rencontre de petites pierres, c’eſt une marque qu’elle <lb/>n’eſt pas encore bien éteinte; </s> <s xml:id="echoid-s3685" xml:space="preserve">de même, ſi on le retire net, cela <pb o="9" file="0187" n="193" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> ſignifiera qu’elle n’eſt pas bien abreuvée, au lieu que ſi la Chaux <lb/>s’y attache, on jugera qu’elle eſt graſſe, gluante, & </s> <s xml:id="echoid-s3686" xml:space="preserve">bien détrempée.</s> <s xml:id="echoid-s3687" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3688" xml:space="preserve">Il y a cependant une excellente qualité de Chaux qui ne ſe fuſe <lb/>point: </s> <s xml:id="echoid-s3689" xml:space="preserve">telle eſt celle de Metz & </s> <s xml:id="echoid-s3690" xml:space="preserve">des environs, où il eſt arrivé que <lb/>des gens, qui n’en connoiſſoient pas la qualité, en avoient fuſé dans <lb/>destrous bien couverts de ſable, & </s> <s xml:id="echoid-s3691" xml:space="preserve">l’année ſuivante elle s’eſt trouvée <lb/>auſſi dure que de la Pierre; </s> <s xml:id="echoid-s3692" xml:space="preserve">il a falu la caſſer avec des coins de fer, <lb/>& </s> <s xml:id="echoid-s3693" xml:space="preserve">l’employer comme du moîlon. </s> <s xml:id="echoid-s3694" xml:space="preserve">Pour éteindre cette Chaux, on <lb/>la couvre de tout le ſable qui doit entrer dans le mortier; </s> <s xml:id="echoid-s3695" xml:space="preserve">& </s> <s xml:id="echoid-s3696" xml:space="preserve">l’on <lb/>jette avec la main de l’eau deſſus, en arroſant, & </s> <s xml:id="echoid-s3697" xml:space="preserve">cela à pluſieurs <lb/>repriſes. </s> <s xml:id="echoid-s3698" xml:space="preserve">Cette Chaux s’éteint ſans qu’il ſorte de fumée au-dehors: <lb/></s> <s xml:id="echoid-s3699" xml:space="preserve">elle fait un ſi bon mortier, qu’à Metz preſque toutes les Caves en <lb/>ſont faites ſans autre mélange que de gros gravier de Riviere, il <lb/>n’y entre ni Pierre ni Brique, & </s> <s xml:id="echoid-s3700" xml:space="preserve">cela fait un maſtic ſi dur, que les <lb/>picques les mieux acerées n’y peuvent mordre, lorſque ce mortier <lb/>a fait corps.</s> <s xml:id="echoid-s3701" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3702" xml:space="preserve">Dans toutes les obſervations qu’on a faites ſur la Chaux, on a <lb/>connu que plus elle eſt vive, plus elle foiſonne quand on l’éteint, <lb/>porte davantage de ſable, fait ſon mortier gras & </s> <s xml:id="echoid-s3703" xml:space="preserve">bon; </s> <s xml:id="echoid-s3704" xml:space="preserve">qu’étant <lb/>gardée long-tems après avoir été éteinte, pourvû qu’elle ſoit dans <lb/>des foſſes bien couvertes de ſable, meilleure elle eſt: </s> <s xml:id="echoid-s3705" xml:space="preserve">c’eſt pour-<lb/>quoi les Romains ne vouloient pas qu’on en employât pour leurs <lb/>Edifices, qu’elle ne fût éteinte depuis deux ou trois ans. </s> <s xml:id="echoid-s3706" xml:space="preserve">On a re-<lb/>marqué encore que la Chaux en pouſſiere ne valoit rien, parce que <lb/>ſon ſel ayant changé de nature & </s> <s xml:id="echoid-s3707" xml:space="preserve">de vertu, elle n’avoit plus celle <lb/>de faire corps dans la maçonnerie.</s> <s xml:id="echoid-s3708" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div256" type="section" level="2" n="76"> <head xml:id="echoid-head207" xml:space="preserve">CHAPITRE QUATRIE’ME.</head> <head xml:id="echoid-head208" style="it" xml:space="preserve">Où l’on explique les qualitez du Sable, de la Pozzolane, & <lb/>du Plâtre.</head> <p> <s xml:id="echoid-s3709" xml:space="preserve">APrès avoir montré, dans le Chapitre précédent, les qualitez <lb/>de la Chaux, nous en allons faire de même pour le Sable, <lb/>afin qu’étant prévenus de tout ce qui regarde ces deux matieres, <lb/>on ſache par leur mélange compoſer un bon mortier: </s> <s xml:id="echoid-s3710" xml:space="preserve">il faut pou-<lb/>voir être Maçon, avant de devenir Architecte; </s> <s xml:id="echoid-s3711" xml:space="preserve">&</s> <s xml:id="echoid-s3712" xml:space="preserve">, puiſqu’il faut né-<lb/>ceſſairement paſſer par-là, je prie ceux qui verront les premiers <lb/>Chapitres de ce Livre de ne point s’ennuyer de la ſterilité des ſu- <pb o="10" file="0188" n="194" rhead="LA SCIENCE DES INGENIEURS,"/> jets qu’on y traite: </s> <s xml:id="echoid-s3713" xml:space="preserve">ils doivent s’eſtimer fort heureux, d’en être <lb/>quittes pour la lecture.</s> <s xml:id="echoid-s3714" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3715" xml:space="preserve">L’on diſtingue principalement deux ſortes de Sable, dont on peut <lb/>ſe ſervir pour faire le mortier; </s> <s xml:id="echoid-s3716" xml:space="preserve">l’un eſt le Sable de Cave, que l’on <lb/>nomme ainſi pour faire entendre qu’on le trouve en foüillant dans <lb/>la terre; </s> <s xml:id="echoid-s3717" xml:space="preserve">l’autre s’apelle Sable de Riviere, parce qu’effectivement <lb/>on le prend dans les lits des Rivieres & </s> <s xml:id="echoid-s3718" xml:space="preserve">des Fleuves. </s> <s xml:id="echoid-s3719" xml:space="preserve">Le Sable de <lb/>Cave ſe rencontre aſſez ſouvent ſans aprofondir beaucoup dans <lb/>la Terre, où il forme preſque toûjours des bancs, dont l’éten-<lb/>duë & </s> <s xml:id="echoid-s3720" xml:space="preserve">l’épaiſſeur changent ſelon la différence des lieux, qui lui <lb/>donnent auſſi une couleur différente; </s> <s xml:id="echoid-s3721" xml:space="preserve">mais comme la couleur ne <lb/>décide rien ſur ſa bonne & </s> <s xml:id="echoid-s3722" xml:space="preserve">mauvaiſe qualité, & </s> <s xml:id="echoid-s3723" xml:space="preserve">qu’il eſt ſeulement <lb/>queſtion du grain, il faut, pour être d’un bon uſage, qu’il ne ſoit <lb/>point gras ni terreux; </s> <s xml:id="echoid-s3724" xml:space="preserve">c’eſt-à-dire, qu’il ne ſoit point mêlé avec de <lb/>la terre; </s> <s xml:id="echoid-s3725" xml:space="preserve">mais au contraire net; </s> <s xml:id="echoid-s3726" xml:space="preserve">enſorte qu’en le frottant entre les <lb/>doigts il raiſonne: </s> <s xml:id="echoid-s3727" xml:space="preserve">celui qui eſt blanc eſt ordinairement le moins char-<lb/>gé deterre, & </s> <s xml:id="echoid-s3728" xml:space="preserve">peut s’employer ſûrement, ayant attention que le grain <lb/>en ſoit d’une certaine groſſeur, car quand il eſt par trop fin & </s> <s xml:id="echoid-s3729" xml:space="preserve">preſ-<lb/>que imperceptible, il ne fait point de corps avec la Chaux, & </s> <s xml:id="echoid-s3730" xml:space="preserve">le <lb/>mortier qui en eſt compoſé ſe réduit par la ſuite en pouſſiere.</s> <s xml:id="echoid-s3731" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3732" xml:space="preserve">Le Sable de Riviere eſt à préférer à celui de Cave, parce qu’il <lb/>eſt moins gras & </s> <s xml:id="echoid-s3733" xml:space="preserve">beaucoup meilleur pour les enduits; </s> <s xml:id="echoid-s3734" xml:space="preserve">ainſi, quand <lb/>on eſt à portée d’en avoir, il faut autant qu’il eſt poſſible ne pas <lb/>le négliger. </s> <s xml:id="echoid-s3735" xml:space="preserve">Il eſt vray qu’il arrive aſſez ſouvent qu’en foüillant pour <lb/>creuſer les fondemens, on en rencontre de Cave, qu’on auroit tort de <lb/>ne point employer, quand il eſt bon; </s> <s xml:id="echoid-s3736" xml:space="preserve">parce que ſe trouvant tout <lb/>porté ſur l’atelier, on évite la dépenſe de l’aller chercher ailleurs, <lb/>& </s> <s xml:id="echoid-s3737" xml:space="preserve">le tranſport de la vuidange des terres qu’il faudroit faire ſans <lb/>cela; </s> <s xml:id="echoid-s3738" xml:space="preserve">mais ce motif, quoique puiſſant pour ceux qui aiment l’œco-<lb/>nomie, ne doit point prévaloir ſur le tort que l’on auroit d’em-<lb/>ployer dans le mortier (comme on fait aſſez ſouvent) une terre <lb/>jaune au lieu de Sable, parce que cette terre aura parû dure & </s> <s xml:id="echoid-s3739" xml:space="preserve"><lb/>ſabloneuſe.</s> <s xml:id="echoid-s3740" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3741" xml:space="preserve">Le Sable de Riviere ſe tire de leurs lits avec des Dragues faites <lb/>à cet uſage: </s> <s xml:id="echoid-s3742" xml:space="preserve">celui qui eſt ſur le rivage n’eſt pas tout-à-fait ſi bon, <lb/>étant ſujet à être mêlé & </s> <s xml:id="echoid-s3743" xml:space="preserve">couvert de vazes, qui eſt une eſpece de <lb/>terre graſſe qui s’y attache dans le tems des grandes eaux & </s> <s xml:id="echoid-s3744" xml:space="preserve">des dé-<lb/>bordemens; </s> <s xml:id="echoid-s3745" xml:space="preserve">cependant, quand il s’en rencontre qui ne participe pas <lb/>de ce mêlange, on peut s’éviter la peine de le pécher, ou bien ſi <lb/>la ſuperficie du rivage eſt chargée de vazes, on en ſera quitte pour <lb/>enlever une eſpece de croute qui s’y rencontre ordinairement, &</s> <s xml:id="echoid-s3746" xml:space="preserve"> <pb o="11" file="0189" n="195" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> prendre le bon ſable qui eſt deſſous, afin de l’avoir pur. </s> <s xml:id="echoid-s3747" xml:space="preserve">Il ſe trouve <lb/>encore un eſpece de Sable apellé gravier, qui étant purgé de tout <lb/>ce qui peut le rendre défectueux eſt auſſi d’un bon uſage; </s> <s xml:id="echoid-s3748" xml:space="preserve">mais, il <lb/>eſt moins eſtimé que le Sable, parce qu’il n’eſt pas ſi menu, étant <lb/>mêlé de petits cailloux qui ne s’incorporent pas bien avec la Chaux, <lb/>& </s> <s xml:id="echoid-s3749" xml:space="preserve">par conſéquent ne peut faire qu’un mortier peu propre à la <lb/>liaiſon des Pierres, à cauſe de l’épaiſſeur & </s> <s xml:id="echoid-s3750" xml:space="preserve">inégalité des joints: <lb/></s> <s xml:id="echoid-s3751" xml:space="preserve">on peut pourtant s’en ſervir dans la conſtruction des fondemens <lb/>& </s> <s xml:id="echoid-s3752" xml:space="preserve">autres gros Ouvrages. </s> <s xml:id="echoid-s3753" xml:space="preserve">Il ſe trouve ſur le bord de la Mer, & </s> <s xml:id="echoid-s3754" xml:space="preserve">dans <lb/>les Terres, un Sable fort menu qu’on apelle ſablon, dont on ſe ſert <lb/>quelques fois comme du Sable ordinaire, mais il n’eſt pas ſi bon; </s> <s xml:id="echoid-s3755" xml:space="preserve"><lb/>cependant, il s’en rencontre d’excellent dans les marais, quand on <lb/>voit qu’en marchant deſſus il en ſort del’eau, ce quilui a fait donner <lb/>le nom de ſable bouillant.</s> <s xml:id="echoid-s3756" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3757" xml:space="preserve">Pour juger du ſable dont on eſt incertain, il faut en jetter dans <lb/>un vaſe plein d’eau claire, & </s> <s xml:id="echoid-s3758" xml:space="preserve">le broüiller enſuite avec la main: </s> <s xml:id="echoid-s3759" xml:space="preserve">ſi <lb/>l’on voit que l’eau devienne noire & </s> <s xml:id="echoid-s3760" xml:space="preserve">bourbeuſe, c’eſt une marque <lb/>qu’il eſt gras & </s> <s xml:id="echoid-s3761" xml:space="preserve">terreux; </s> <s xml:id="echoid-s3762" xml:space="preserve">ſi au contraire l’eau eſt preſque auſſi claire <lb/>qu’auparavant, ou n’eſt devenuë qu’un peu trouble, on ſera con-<lb/>vaincu que le ſable eſt pur & </s> <s xml:id="echoid-s3763" xml:space="preserve">net.</s> <s xml:id="echoid-s3764" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3765" xml:space="preserve">Il ſe fait encore un mortier de deux eſpeces de poudre. </s> <s xml:id="echoid-s3766" xml:space="preserve">La pre-<lb/>miere eſt la Pozzolane, dont la couleur eſt rougeatre: </s> <s xml:id="echoid-s3767" xml:space="preserve">elle ſe trouve <lb/>en Italie, & </s> <s xml:id="echoid-s3768" xml:space="preserve">au Pays de Bayes. </s> <s xml:id="echoid-s3769" xml:space="preserve">Cette poudre eſt très-bonne pour les <lb/>Bàtimens; </s> <s xml:id="echoid-s3770" xml:space="preserve">& </s> <s xml:id="echoid-s3771" xml:space="preserve">rien au monde ne lie mieux les Pierres que le mor-<lb/>tier qui en eſt fait, non ſeulement pour la maçonnerie des Edifices <lb/>qui s’élevent dansles lieuxſecs, mais particulierement pour ceux qui <lb/>ſe fabriquent au fond de la Mer & </s> <s xml:id="echoid-s3772" xml:space="preserve">dans les Eaux, faiſant corps <lb/>peu après avoir été employé, parce qu’elle ſe durcit dans l’eau, <lb/>comme nous l’expliquerons plus amplement ailleurs. </s> <s xml:id="echoid-s3773" xml:space="preserve">Je crois que <lb/>cette poudre n’eſt autre choſe que la terre & </s> <s xml:id="echoid-s3774" xml:space="preserve">le tuf qui ſont brûlez <lb/>par les feux ſoûterains qui ſortent des montagnes, aux environs <lb/>deſquels on la tire; </s> <s xml:id="echoid-s3775" xml:space="preserve">& </s> <s xml:id="echoid-s3776" xml:space="preserve">voici ce me ſemble la raiſon de ſon admi-<lb/>rable propriété.</s> <s xml:id="echoid-s3777" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3778" xml:space="preserve">Comme la Thuille, qui eſt une compoſition de terre, n’a point <lb/>de vertu avant la cuiſſon pour agir avec la Chaux, & </s> <s xml:id="echoid-s3779" xml:space="preserve">qu’après être <lb/>cuite & </s> <s xml:id="echoid-s3780" xml:space="preserve">réduite en poudre, elle fait un mortier excellent, de même <lb/>la terre bitumineuſe qui ſe trouve au Royaume de Naples, étant <lb/>brûlée par les feux ſouterains, les petites parties qui en réſultent, <lb/>& </s> <s xml:id="echoid-s3781" xml:space="preserve">qu’on peut regarder comme une cendre, compoſent la poudre <lb/>de Pozzolane qui doit par conſéquent participer des proprietez du <lb/>ciment: </s> <s xml:id="echoid-s3782" xml:space="preserve">d’ailleurs, la nature du terrain peut y avoir auſſi beaucoup <pb o="12" file="0190" n="196" rhead="LA SCIENCE DES INGENIEURS,"/> de part, auſſi-bien que l’effet que produit le feu. </s> <s xml:id="echoid-s3783" xml:space="preserve">Il y a aparence <lb/>que l’on nomme cette poudre Pozzolane, parce qu’elle ſe trouve <lb/>dans le territoire de la Ville de Pozzol, ſi fameuſe par ſes grotes, <lb/>& </s> <s xml:id="echoid-s3784" xml:space="preserve">ſes eaux minérales.</s> <s xml:id="echoid-s3785" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3786" xml:space="preserve">L’autre eſpece de poudre eſt faite d’une terre qui ſe trouve aſſez <lb/>près du bas Rhin en Allemagne & </s> <s xml:id="echoid-s3787" xml:space="preserve">aux environs de Cologne, on <lb/>la cuit commele Plâtre, enſuite on l’écraſe avec des meules à Mou-<lb/>lin pour la réduire en poudre, elle eſt ſi commune aux Pays-Bas, <lb/>qu’elle en a retenu le nom, la nommant Terraſſe de Hollande, elle <lb/>eſt de couleur griſe, & </s> <s xml:id="echoid-s3788" xml:space="preserve">lorſqu’elle eſt pure & </s> <s xml:id="echoid-s3789" xml:space="preserve">qu’elle n’eſt point fal-<lb/>ſifiée, ce qui eſt aſſez rare, elle eſt excellente dans les Ouvrages <lb/>qui ſont baignez des eaux, & </s> <s xml:id="echoid-s3790" xml:space="preserve">réſiſte également à l’injure des ſaiſons <lb/>différentes, l’humidité & </s> <s xml:id="echoid-s3791" xml:space="preserve">la ſéchereſſe ne pouvant l’alterer, elle re-<lb/>tient les Pierres & </s> <s xml:id="echoid-s3792" xml:space="preserve">les autres matériaux enſemble avec une force & </s> <s xml:id="echoid-s3793" xml:space="preserve"><lb/>une fermeté inébranlable, ce qui fait qu’on l’employe en France & </s> <s xml:id="echoid-s3794" xml:space="preserve"><lb/>aux Pays-Bas dans la conſtruction des Ouvrages aquatiques, par la <lb/>difficulté d’avoir de la Pozzolane à juſte prix: </s> <s xml:id="echoid-s3795" xml:space="preserve">la Cendrée de Tournay <lb/>eſt auſſi merveilleuſe, comme nousle ferons voir au Chap. </s> <s xml:id="echoid-s3796" xml:space="preserve">ſuivant.</s> <s xml:id="echoid-s3797" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3798" xml:space="preserve">On ſe ſert encore, au lieu de ſable, de certaine poudre artificielle <lb/>d’un très-bon uſagepour les Bâtimens, on fait piler des fragemens de <lb/>pots & </s> <s xml:id="echoid-s3799" xml:space="preserve">autres vaſes de Grais & </s> <s xml:id="echoid-s3800" xml:space="preserve">des morceaux de mache-fer, prove-<lb/>nans du Carbon de Terre brûlé dans les Forges, leſquels étant <lb/>réduits en poudre, on y mêle une pareille quantité de Ciment de <lb/>Pierre de meule de Moulin & </s> <s xml:id="echoid-s3801" xml:space="preserve">de Chaux, dont on compoſe un <lb/>mortier excellent qui réſiſte parfaitement à l’eau ſi les Ouvrages où <lb/>on l’employe en ſont baignez, comme ſont les Ecluſes, Ponts, <lb/>Citernes, Réſervoirs, &</s> <s xml:id="echoid-s3802" xml:space="preserve">c. </s> <s xml:id="echoid-s3803" xml:space="preserve">On fait auſſi un amas de Cailloux qui ſe <lb/>trouvent dans les Campagnes, ou de galets qu’on prend ſur le bord <lb/>des fleuves, qu’on met au Fourneau, & </s> <s xml:id="echoid-s3804" xml:space="preserve">après les avoir fait rougir, <lb/>on les retire, puis on les fait piler & </s> <s xml:id="echoid-s3805" xml:space="preserve">réduire en poudre, ce qui en <lb/>fait une d’un auſſi bon uſage que la Terraſſe de Hollande.</s> <s xml:id="echoid-s3806" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3807" xml:space="preserve">Il nous reſte encore à parler du Plâtre, qui eſt une matiere qui <lb/>demanderoit elle ſeule une grande Diſſertation, ſi l’on vouloit en-<lb/>trer dans les cauſes phyſiques de ſes proprietez; </s> <s xml:id="echoid-s3808" xml:space="preserve">mais, je me trouve <lb/>malgré moi dans la neceſſité de paſſer ſous ſilence bien des Remar-<lb/>ques curieuſes qui groſſiroient cet Ouvrage aſſez inutilement: </s> <s xml:id="echoid-s3809" xml:space="preserve">j’ai <lb/>tant de ſujets différens à traiter, que j’aprehende en voulant m’ar-<lb/>rêter ſur certains objets abondans, qu’il ne m’échape d’ailleurs d’au-<lb/>tres vûës plus utiles à la perfection du deſſein que je veux remplir.</s> <s xml:id="echoid-s3810" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3811" xml:space="preserve">Le Plâtre ſe fait d’une Pierre de couleur griſàtre qui ne ſe <lb/>trouve que dans certains Pays, particulierement aux environs de <pb o="13" file="0191" n="197" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> Paris, on la fait cuire au feu comme la Chaux; </s> <s xml:id="echoid-s3812" xml:space="preserve">mais elle en eſt bien <lb/>differente, car la Chaux ne peut être employée ſans le mélange de <lb/>quelque autre matiere qui la ſoutienne & </s> <s xml:id="echoid-s3813" xml:space="preserve">lui donne plus de corps <lb/>qu’elle n’en a naturellement, au lieu que le Plâtre s’employe tout <lb/>pur, il fuffit de l’abreuver avec de l’eau, & </s> <s xml:id="echoid-s3814" xml:space="preserve">auſſi-tôt on le met en <lb/>œuvre, car il a cela de particulier, que s’il n’eſt pas employé ſur <lb/>le champ après l’avoir abreuvé, il ſe ſéche & </s> <s xml:id="echoid-s3815" xml:space="preserve">ne peut plus s’apliquer <lb/>contre d’autres corps, ni recevoir les differentes impreſſions qu’on <lb/>veut lui donner pour faire des ornemens d’Architecture, comme <lb/>ſa principale qualité eſt de faire corps dans le moment qu’on le met <lb/>en œuvre, il n’y a point de matiere dont on puiſſe ſe ſervir plus <lb/>utilement dans la conſtruction des Bâtimens & </s> <s xml:id="echoid-s3816" xml:space="preserve">ſur laquelle on ſoit <lb/>plus ſujet à être trompé par ceux qui la débitent, tantôt le Plâtre <lb/>ſera mauvais pour être éventé, tantôt parce que la cuiſſon en aura <lb/>été mal faite, ce qui arrive le plus ſouvent; </s> <s xml:id="echoid-s3817" xml:space="preserve">car comme celui, qui <lb/>étoit aux extrêmitez du Four, n’a pas eû un dégré de chaleur ſuf-<lb/>fiſant pour être calciné juſqu’à un certain point, il n’y a gueres que <lb/>celui du milieu, qui l’a été comme il faut, cependant quand la cuiſ-<lb/>ſon eſt faite, les Chau-fouriers le mélent tout enſemble, & </s> <s xml:id="echoid-s3818" xml:space="preserve">quand <lb/>il eſt en poudre, celui des extrêmitez du Four eſt confondu avec <lb/>celui du milieu, ce dernier qui eût été excellent s’il avoit été em-<lb/>ployé à part, eſt alteré par le mélange qu’on en a fait, & </s> <s xml:id="echoid-s3819" xml:space="preserve">ne vaut <lb/>pas à beaucoup près ce qu’il étoit auparavant; </s> <s xml:id="echoid-s3820" xml:space="preserve">c’eſt pourquoi dans <lb/>les Ouvrages de conſéquence qui ſe font avec le Plâtre, il faudroit <lb/>ne ſe ſervir que de celui qui a été dans le milieu du Four, & </s> <s xml:id="echoid-s3821" xml:space="preserve">avoir <lb/>pour cela des gens ſur le lieu qui le choiſiſſent, on en ſera quitte <lb/>s’il le faut à le payer davantage que celui qu’on vend dans les ſacs; <lb/></s> <s xml:id="echoid-s3822" xml:space="preserve">je voudrois même plus, c’eſt que ne pouvant pas compter ſur les <lb/>Chau-fouriers on ſuivit la cuiſſon depuis le commencement juſ-<lb/>qu’à la fin, pour avoir attention que les Pierres ſoyent bien ran-<lb/>gées dans le Four; </s> <s xml:id="echoid-s3823" xml:space="preserve">enſorte que les unes ne ſoient pas abſolument <lb/>embraſées, comme ſont celles qui ſont près le foyer, tandis que <lb/>les autres qui ſont plus loin ne reſſentent qu’à peine l’action du feu, <lb/>qui faute de jour n’aura pû s’introduire à la ronde, d’ailleurs la <lb/>bonne cuiſſon conſiſte auſſi à ménager un dégré de chaleur qui peu à <lb/>peu déſeichant l’humidité de la pierre faſſe évaporer le ſouffre qu’elle <lb/>renferme & </s> <s xml:id="echoid-s3824" xml:space="preserve">la purge des parties de terre dont elle peut être mêlée, <lb/>prenant garde que la violence de la flame ne cauſe un déſeiche-<lb/>ment abſolu; </s> <s xml:id="echoid-s3825" xml:space="preserve">car comme il y a aparence que la vertu du Plâtre <lb/>eſt cauſée par un ſel, qui fait que ſes parties s’accrochent les unes <lb/>aux autres, dès que ce ſel eſt trop déſeiché, il n’y a plus de liaiſon, <pb o="14" file="0192" n="198" rhead="LA SCIENCE DES INGENIEURS,"/> & </s> <s xml:id="echoid-s3826" xml:space="preserve">c’eſt ce que j’ai vû pluſieurs fois remarquer à des Plâtriers, qui <lb/>étoient étonnez de voir qu’ils ne pouvoient pas mettre en œuvre <lb/>du Plâtre nouveau, dont ils croyoient être ſurs, parce qu’ils étoient <lb/>convaincus qu’il n’y avoit aucun mélange.</s> <s xml:id="echoid-s3827" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3828" xml:space="preserve">Quand la cuiſſon a été bien faite, il eſt facile de le connoître, par-<lb/>ce que pour lors le Plâtre a une certaine onctuoſité & </s> <s xml:id="echoid-s3829" xml:space="preserve">une graiſſe <lb/>qui cole aux doitgs quand on le manie, au contraire ſi elle a été mal <lb/>faite, le Plâtre a de la rudeſſe & </s> <s xml:id="echoid-s3830" xml:space="preserve">ne s’attache point comme l’autre, <lb/>après cela toute bonne que puiſſe être cette cuiſſon, elle devient <lb/>pour ainſi dire nulle, quand on veut employer du Plâtre qui a été <lb/>gardé long-tems; </s> <s xml:id="echoid-s3831" xml:space="preserve">car cette matiere reſſemble aux liqueurs exquiſes <lb/>qui n’ont de ſaveur qu’autant qu’on a eû ſoin de ne pas laiſſer éva-<lb/>porer les eſprits qui en font toute la bonté; </s> <s xml:id="echoid-s3832" xml:space="preserve">ſi le Plâtre n’eſt pas <lb/>bien renfermé dans des tonneaux, placez dans des lieux ſecs, <lb/>il s’évente; </s> <s xml:id="echoid-s3833" xml:space="preserve">c’eſt-à-dire, que le ſel qui en fait toute la vertu s’éva-<lb/>pore, & </s> <s xml:id="echoid-s3834" xml:space="preserve">il ne reſte qu’une eſpece de cendre qui étant employée ne <lb/>fait plus corps, ainſi l’état le plus convenable où l’on doit prendre <lb/>le Plâtre, c’eſt de l’employer au ſortir du Four quand on eſt à portée <lb/>d’en uſer de la ſorte: </s> <s xml:id="echoid-s3835" xml:space="preserve">l’on remarquera encore que toutes les ſaiſons <lb/>ne ſont pas propres pour le mettre en œuvre, ſi l’on s’en ſert en <lb/>Hyver, ou à la fin de l’Automne, les Ouvrages qui en ſont faits <lb/>ſont de peu de durée, & </s> <s xml:id="echoid-s3836" xml:space="preserve">ſujets à tomber par éclats, parce qu’alors <lb/>le froid ſaiſit tout d’un coup le Plâtre, il glace l’humidité de l’eau <lb/>avec laquelle il a été gâché, & </s> <s xml:id="echoid-s3837" xml:space="preserve">l’eſprit du Plâtre étant amorti il <lb/>ne peut plus y avoir d’union, enfin quand on n’eſt point à portée <lb/>de prendre toutes les meſures dont je viens de parler pour s’aſſu-<lb/>rer de la bonté du Plâtre, on pourra au moins choiſir le meilleur <lb/>de celui qui ſe trouve en magaſin, puiſque pour le connoître il ne <lb/>faut qu’en détremper un peu dans la main; </s> <s xml:id="echoid-s3838" xml:space="preserve">celui qui ſe prendra le <lb/>plus promptement ſera à préférer à d’autre qui ne fera qu’une eſ-<lb/>pece de Mortier ſans conſiſtance.</s> <s xml:id="echoid-s3839" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div257" type="section" level="2" n="77"> <head xml:id="echoid-head209" xml:space="preserve">CHAPITRE CINQUIE’ME.</head> <head xml:id="echoid-head210" style="it" xml:space="preserve">De la Compoſition du Mortier.</head> <p> <s xml:id="echoid-s3840" xml:space="preserve">NOus avons dit en parlant de la Chaux dans le troiſiéme Cha-<lb/>pitre, qu’après l’avoir éteinte dans des baſſins creuſés en ter-<lb/>re, il étoit à propos de la laiſſer repoſer long-tems avant de la mêler <pb o="15" file="0193" n="199" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> avec le ſable pour faire le mortier, parce qu’en effet rien ne la rend <lb/>meilleure que cette ſage précaution; </s> <s xml:id="echoid-s3841" xml:space="preserve">mais comme il n’eſt guere <lb/>poſſible d’en uſer ainſi, à cauſe de l’impatience où l’on eſt d’executer <lb/>un ouvrage auſſi-tôt qu’il eſt projeté, je vais décrire la façon la plus <lb/>ordinaire dont on prépare la Chaux afin de pouvoir faire du mor-<lb/>tier incontinent après.</s> <s xml:id="echoid-s3842" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3843" xml:space="preserve">L’on fait un petit baſſin en terre, auprès duquel on en creuſe un <lb/>autre plus grand & </s> <s xml:id="echoid-s3844" xml:space="preserve">plus profond, on met dans le petit une certaine <lb/>quantité de Chaux ſur laquelle on jette de l’eau pour la broyer <lb/>avec le rabot, & </s> <s xml:id="echoid-s3845" xml:space="preserve">après qu’elle eſt devenuë liquide, on la fait cou-<lb/>ler dans le grand baſſin où elle ſe prend enſuite comme un fromage <lb/>blanc, c’eſt delà qu’on la tire pour la mêler avec le ſable. </s> <s xml:id="echoid-s3846" xml:space="preserve">Ce mê-<lb/>lange ſe fait ordinairement de deux tiers de ſable ſur un tiers de <lb/>Chaux meſurée vive, ou de trois cinquiémes de ſable, ſur deux cin-<lb/>quiémes de Chaux, ſelon qu’elle foiſonne plus ou moins; </s> <s xml:id="echoid-s3847" xml:space="preserve">car quand <lb/>elle eſt graſſe & </s> <s xml:id="echoid-s3848" xml:space="preserve">faite de bons Cailloux, on peut mettre juſqu’à <lb/>trois quarts de ſable ſur un quart de Chaux: </s> <s xml:id="echoid-s3849" xml:space="preserve">ce qui n’eſt pourtant pas <lb/>ordinaire, parce qu’il eſt rare d’avoir de la Chaux aſſez graſſe pour <lb/>porter tant de ſable: </s> <s xml:id="echoid-s3850" xml:space="preserve">on ne doit tirer le ſable qu’à meſure qu’on <lb/>l’employe, ſans en faire de proviſion long-tems auparavant, l’ex-<lb/>perience faiſant voir que le Soleil l’altere, le déſeiche, & </s> <s xml:id="echoid-s3851" xml:space="preserve">lui ôte <lb/>une certaine graiſſe qui en fait toute la bonté; </s> <s xml:id="echoid-s3852" xml:space="preserve">d’un autre côté la <lb/>pluye en diſſoud les ſels volatils, & </s> <s xml:id="echoid-s3853" xml:space="preserve">par la ſuite il ſe change en une <lb/>eſpece de terre qui étant mêlée avec la Chaux ne fait plus corps <lb/>ni liaiſon dans la maçonnerie. </s> <s xml:id="echoid-s3854" xml:space="preserve">Cependant, il eſt à remarquer que <lb/>s’il eſt queſtion de faire des enduits, il n’y a point de mal que le <lb/>ſable ne ſoit pas ſi gras, parce qu’autrement il ſe ſeiche fort promp-<lb/>tement, fait gerſer le mortier, & </s> <s xml:id="echoid-s3855" xml:space="preserve">par conſéquent empêche que <lb/>l’enduit ne reſte poli.</s> <s xml:id="echoid-s3856" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3857" xml:space="preserve">Le ciment ſe mêle auſſi avec la Chaux en plus petite ou plus <lb/>grande quantité ſelon qu’elle faiſonne plus ou moins, les doſes <lb/>ſont les mêmes dont nous venons de parler: </s> <s xml:id="echoid-s3858" xml:space="preserve">cependant, l’on fait <lb/>aſſez ſouvent du mortier compoſé de moitié ſable & </s> <s xml:id="echoid-s3859" xml:space="preserve">moitié ciment, <lb/>dont l’uſage eſt très-bon pour des Ouvrages qui ne ſont point de <lb/>la derniere conſéquence, mais qui méritent pourtant quelqu’at-<lb/>tention.</s> <s xml:id="echoid-s3860" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3861" xml:space="preserve">Le mortier de Pozzolane ſe fait à peu-près comme celui de ſa-<lb/>ble; </s> <s xml:id="echoid-s3862" xml:space="preserve">il ſert comme nous avons dit ailleurs pour la conſtruction des <lb/>Ouvrages que l’on fabrique dans l’eau.</s> <s xml:id="echoid-s3863" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3864" xml:space="preserve">Pour faire le mortier de Terraſſe on choiſit la meilleure Chaux <lb/>non éteinte, & </s> <s xml:id="echoid-s3865" xml:space="preserve">on en prend autant qu’on en veut employer pen- <pb o="16" file="0194" n="200" rhead="LA SCIENCE DES INGENIEURS,"/> dant une ſemaine, on en étend environ un pied de hauteur ſur une <lb/>aire ou batterie, on l’arroſe pour l’éteindre, & </s> <s xml:id="echoid-s3866" xml:space="preserve">enſuite on couvre <lb/>ce lit de Chaux, d’un autre de Terraſſe d’environ un pied d’épaiſſeur, <lb/>on laiſſe repoſer cette préparation pendant deux ou trois jours, afin <lb/>de donner le tems à la Chaux de s’éteindre; </s> <s xml:id="echoid-s3867" xml:space="preserve">après quoi les Manœu-<lb/>vres viennent avec des houës broüiller & </s> <s xml:id="echoid-s3868" xml:space="preserve">mêler enſemble la Ter-<lb/>raſſe & </s> <s xml:id="echoid-s3869" xml:space="preserve">la Chaux dont ils font un gros tas qu’on laiſſe repoſer envi-<lb/>ron deux jours, au bout deſquels on broüille de rechef une partie <lb/>de cette préparation, la moüillant de tems en tems juſqu’à ce qu’on <lb/>s’aperçoive que le mortier eſt de bonne conſiſtance: </s> <s xml:id="echoid-s3870" xml:space="preserve">& </s> <s xml:id="echoid-s3871" xml:space="preserve">quand on <lb/>en eſt là, on l’employe auſſi-tôt aux Ouvrages pour leſquels il eſt <lb/>deſtiné; </s> <s xml:id="echoid-s3872" xml:space="preserve">mais on prendra garde de ne donner cette derniere façon au <lb/>mortier que la veille du jour qu’on ſe propoſe de l’employer; </s> <s xml:id="echoid-s3873" xml:space="preserve">c’eſt-<lb/>à-dire de n’en broüiller qu’autant qu’on aura beſoin ce jour-là, ob-<lb/>ſervant la même choſe pour les jours ſuivans tant qu’il y aura de <lb/>cette compoſition dans le tas. </s> <s xml:id="echoid-s3874" xml:space="preserve">Dans pluſieurs Provinces on prépare <lb/>le mortier ordinaire de la même façon qu’on vient de voir pour la <lb/>Terraſſe; </s> <s xml:id="echoid-s3875" xml:space="preserve">cette pratique n’eſt pas mauvaiſe, & </s> <s xml:id="echoid-s3876" xml:space="preserve">on ne peut que s’en <lb/>bien trouver.</s> <s xml:id="echoid-s3877" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3878" xml:space="preserve">Outre la Terraſſe de Hollande, on ſe ſert encore en Flandres <lb/>d’une poudre qu’on nomme communément Cendrée de Tournay, <lb/>qui s’employe fort utilement pour la compoſition du mortier des <lb/>Ouvrages qui ſe font dans l’eau: </s> <s xml:id="echoid-s3879" xml:space="preserve">comme perſonne (à ce que je <lb/>croi) n’en a bien expliqué les propriétés, & </s> <s xml:id="echoid-s3880" xml:space="preserve">la maniere de l’em-<lb/>ployer, je vais raporter en peu de mots ce que j’en ſçai.</s> <s xml:id="echoid-s3881" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3882" xml:space="preserve">Les environs de Tournay fourniſſent une Pierre bleuë très-dure, <lb/>& </s> <s xml:id="echoid-s3883" xml:space="preserve">qui fait une Chaux excellente; </s> <s xml:id="echoid-s3884" xml:space="preserve">quand cette Pierre eſt dans le <lb/>Four, il s’en détache des petites parcelles qui tombent ſous la <lb/>grille du Fourneau où elles ſe mêlent avec la cendre du Charbon <lb/>de terre, & </s> <s xml:id="echoid-s3885" xml:space="preserve">comme cette cendre n’eſt autre choſe que des petites <lb/>parties de la hoüille calcinée, c’eſt le mêlange qui s’en fait qui com-<lb/>poſe la Cendrée de Tournay qui ſe débite par les Marchands telle <lb/>qu’on la tire des Fourneaux.</s> <s xml:id="echoid-s3886" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3887" xml:space="preserve">L’experience faiſant voir que la Pierre dure fait toûjours de <lb/>bonne Chaux & </s> <s xml:id="echoid-s3888" xml:space="preserve">un mortier excellent pour les Ouvrages aquatiques, <lb/>quand elle eſt mêlée avec de la poudre provenante du Charbon ou <lb/>mâche-fer qu’on tire des Forges, comme je l’ay expliqué dans le <lb/>quatriéme Chapitre: </s> <s xml:id="echoid-s3889" xml:space="preserve">il n’eſt pas étonnant que la Cendrée de Tour-<lb/>nay ſoit merveilleuſe pour le même uſage, puiſqu’elle participe <lb/>à la fois des qualités de ces deux matieres; </s> <s xml:id="echoid-s3890" xml:space="preserve">car je ne doute pas que <lb/>les petites parties de Charbon qui ſe trouvent mêlées avec la Cen- <pb o="17" file="0195" n="201" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> drée ne contribuent beaucoup à lui donner la propriété de ſe durcir <lb/>dans l’eau comme on le verra plus bas; </s> <s xml:id="echoid-s3891" xml:space="preserve">ainſi, ſans m’arrêter à des <lb/>Diſſertations Phiſiques, je paſſe à la maniere de s’en ſervir.</s> <s xml:id="echoid-s3892" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3893" xml:space="preserve">La premiere attention, que l’on doit avoir avant de la préparer, eſt <lb/>de bien balayer le terrain ſur lequel on la doit jetter, on l’éteint <lb/>enſuite dans une eſpece de baſſin avec une quantité d’eau ſuffiſante <lb/>ſeulement pour la bien fondre & </s> <s xml:id="echoid-s3894" xml:space="preserve">démêler, après quoi on la paſſe <lb/>avec une claye faite de fil d’archal qu’on met au-deſſus d’une bat-<lb/>terie faite exprès, pavée de pierres plates & </s> <s xml:id="echoid-s3895" xml:space="preserve">unies, & </s> <s xml:id="echoid-s3896" xml:space="preserve">conſtruite de <lb/>même par les côtés: </s> <s xml:id="echoid-s3897" xml:space="preserve">tout ce qui ne paſſe pas au travers de la claye <lb/>eſt rebuté; </s> <s xml:id="echoid-s3898" xml:space="preserve">on bat ce qui eſt dans cette batterie à pluſieurs repriſes <lb/>pendant dix ou douze jours conſecutifs avec une dame du poids <lb/>de 30 livres ferrée par le deſſous, juſqu’à ce qu’enfin elle compoſe <lb/>une pâte bien graſſe & </s> <s xml:id="echoid-s3899" xml:space="preserve">bien fine, on l’employe ſur le champ, ſinon <lb/>elle peut ſe conſerver pluſieurs mois de ſuite ſans rien perdre de ſa <lb/>qualité, pourvû que l’on aye ſoin de la couvrir; </s> <s xml:id="echoid-s3900" xml:space="preserve">car le ſoleil, la <lb/>pouſſiere, & </s> <s xml:id="echoid-s3901" xml:space="preserve">la pluye la gâtent; </s> <s xml:id="echoid-s3902" xml:space="preserve">il faut avoir attention, quand on la <lb/>rebat pour s’en ſervir, de n’y mêler que très-peu d’eau & </s> <s xml:id="echoid-s3903" xml:space="preserve">même point <lb/>du tout s’il ſe peut; </s> <s xml:id="echoid-s3904" xml:space="preserve">car à force de bras elle devient graſſe & </s> <s xml:id="echoid-s3905" xml:space="preserve">liquide <lb/>ſans qu’on ſoit obligé de l’humecter de nouveau: </s> <s xml:id="echoid-s3906" xml:space="preserve">ainſi c’eſt ordinai-<lb/>rement la pareſſe des ouvriers, & </s> <s xml:id="echoid-s3907" xml:space="preserve">non pas la neceſſité, qui les enga-<lb/>gent à y mettre beaucoup d’eau pour la rebattre, ce qui la dégraiſ-<lb/>ſeroit peu à peu & </s> <s xml:id="echoid-s3908" xml:space="preserve">diminueroit ſa bonté ſi on n’y prenoit garde.</s> <s xml:id="echoid-s3909" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3910" xml:space="preserve">Il y en a qui pour la préparer ſe ſervent de deux baſſins, l’un plus <lb/>elevé que l’autre, tous deux bien pavés & </s> <s xml:id="echoid-s3911" xml:space="preserve">diſpoſés; </s> <s xml:id="echoid-s3912" xml:space="preserve">enſorte que ce <lb/>qui eſt dans l’un puiſſe couler dans l’autre par une petite grille que <lb/>l’on a ſoin de maſquer quand on éteint & </s> <s xml:id="echoid-s3913" xml:space="preserve">démêle la cendrée, dès <lb/>qu’on juge qu’elle l’eſt ſuffiſamment, on débouche la grille, tout ce <lb/>qui ne peut pas paſſer au travers eſt rebuté, & </s> <s xml:id="echoid-s3914" xml:space="preserve">ce qui coule dans <lb/>l’autre baſſin eſt deſtiné à être rebatu comme on vient de le dire.</s> <s xml:id="echoid-s3915" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3916" xml:space="preserve">On ſe ſert de cette cendrée pour la Maçonnerie des Ecluſes, Ponts, <lb/>Acqueducs, Battard’eaux, &</s> <s xml:id="echoid-s3917" xml:space="preserve">c. </s> <s xml:id="echoid-s3918" xml:space="preserve">& </s> <s xml:id="echoid-s3919" xml:space="preserve">generalement dans les Maçonne-<lb/>ries ordinaires pour aſſéoir les Grais & </s> <s xml:id="echoid-s3920" xml:space="preserve">les rejointoyer; </s> <s xml:id="echoid-s3921" xml:space="preserve">ce qui ſe doit <lb/>faire depuis le mois d’Avril juſqu’à la fin de Juillet, parce qu’em-<lb/>ployé dans ce tems-là il n’éclate jamais, ce qui eſt une propriété <lb/>remarquable de la Cendrée; </s> <s xml:id="echoid-s3922" xml:space="preserve">car la plûpart des cimens ſont ſujets à <lb/>gerſer; </s> <s xml:id="echoid-s3923" xml:space="preserve">la Chaux de Boulogne par exemple, qui eſt excellente quand <lb/>elle eſt employée dans l’eau ne vaut rien à ſec.</s> <s xml:id="echoid-s3924" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3925" xml:space="preserve">On la mêle quelquefois pour plus de précaution avec un ſixié-<lb/>me de Thuilleau paſſé au tamis, & </s> <s xml:id="echoid-s3926" xml:space="preserve">je crois que ſi on la mêloit avec <lb/>de la Terraſſe de Hollande, on pourroit s’en ſervir avec un ſuccès <pb o="18" file="0196" n="202" rhead="LA SCIENCE DES INGENIEURS,"/> merveilleux dans la conſtruction des citernes; </s> <s xml:id="echoid-s3927" xml:space="preserve">car je ne doute pas <lb/>que ces deux matieres enſemble ne compoſent le plus excellent <lb/>ciment qu’il ſoit poſſible d’imaginer.</s> <s xml:id="echoid-s3928" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3929" xml:space="preserve">Dans les Pays où la bonne Chaux eſt rare, l’on en met quelque <lb/>fois en œuvre de deux eſpeces ſur les grands atteliers, l’une faite <lb/>de bonnes pierres dures & </s> <s xml:id="echoid-s3930" xml:space="preserve">l’autre de pierres communes; </s> <s xml:id="echoid-s3931" xml:space="preserve">la premiere <lb/>comme la meilleure s’employe pour faire ce qu’on apelle le bon <lb/>mortier dont on ſe ſert pour les ouvrages qui méritent attention, & </s> <s xml:id="echoid-s3932" xml:space="preserve"><lb/>l’autre pour faire celui qu’on nomme mortier blanc, qui, n’étant pas <lb/>d’une trop bonne qualité, ne s’employe qu’aux fondations & </s> <s xml:id="echoid-s3933" xml:space="preserve">dans <lb/>le maſſif des gros murs; </s> <s xml:id="echoid-s3934" xml:space="preserve">on fait encore un mortier que l’on apelle <lb/>bâtard, parce qu’il eſt compoſé à la fois de bonne & </s> <s xml:id="echoid-s3935" xml:space="preserve">mauvaiſe Chaux <lb/>dont on ſe ſert auſſi pourles murs d’une épaiſſeur conſiderable; </s> <s xml:id="echoid-s3936" xml:space="preserve">mais <lb/>il faut prendre garde de ne point en employer dansles ouvrages qui <lb/>ſont baignés des eaux.</s> <s xml:id="echoid-s3937" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3938" xml:space="preserve">On peut ſe ſervir indifferemment de toute ſorte d’eau pour étein-<lb/>dre la chaux, excepté celle des Marais & </s> <s xml:id="echoid-s3939" xml:space="preserve">les autres bourbeuſes & </s> <s xml:id="echoid-s3940" xml:space="preserve"><lb/>qui croupiſſent; </s> <s xml:id="echoid-s3941" xml:space="preserve">c’eſt pourquoi on ne doit point permettre aux <lb/>Maçons d’employer celles qui courent dans les ruës & </s> <s xml:id="echoid-s3942" xml:space="preserve">qu’ils raſſem-<lb/>blent par le moyen d’une petite digue, parce qu’étant chargées <lb/>d’ordures, elles ne peuvent faire que du mauvais mortier. </s> <s xml:id="echoid-s3943" xml:space="preserve">Autre-<lb/>fois on ne vouloit point ſe ſervir d’eau de la mer, parce qu’on <lb/>croïoit qu’à cauſe qu’elle eſt ſalée le mortier ne ſéchoit qu’avec pei-<lb/>ne; </s> <s xml:id="echoid-s3944" xml:space="preserve">mais l’on prétend aujourd’hui que c’eſt une erreur, & </s> <s xml:id="echoid-s3945" xml:space="preserve">qu’elle eſt <lb/>auſſi bonne & </s> <s xml:id="echoid-s3946" xml:space="preserve">même meilleure que celle de Riviere; </s> <s xml:id="echoid-s3947" xml:space="preserve">mais c’eſt ce <lb/>que je ne deciderai pas n’en ayant point fait d’experience: </s> <s xml:id="echoid-s3948" xml:space="preserve">je ſçai <lb/>ſeulement qu’on s’en eſt ſervi dans des endroits où elle a fait du mor-<lb/>tier excellent, & </s> <s xml:id="echoid-s3949" xml:space="preserve">dont on s’eſt parfaitement bien trouvé; </s> <s xml:id="echoid-s3950" xml:space="preserve">& </s> <s xml:id="echoid-s3951" xml:space="preserve">que <lb/>dans d’autres Provinces au contraire le mortier qui en étoit abreuvé <lb/>avoit toutes les peines du monde à ſécher. </s> <s xml:id="echoid-s3952" xml:space="preserve">Ce qui me fait croire <lb/>que quand la Chaux eſt forte & </s> <s xml:id="echoid-s3953" xml:space="preserve">graſſe, on peut ſe ſervir de l’eau <lb/>de la mer; </s> <s xml:id="echoid-s3954" xml:space="preserve">mais que ſi elle eſt d’une mauvaiſe qualité, cette eau <lb/>la rend encore plus foible: </s> <s xml:id="echoid-s3955" xml:space="preserve">car c’eſt un principe de chimie que de <lb/>deux ſels differens mis enſemble, il y en a toûjours un qui conver-<lb/>tit l’autre en ſa ſubſtance, ainſi il y a aparence que quand les ſels de <lb/>la Chaux ſont abondants, ils attirent ceux que contient l’eau de la <lb/>mer, & </s> <s xml:id="echoid-s3956" xml:space="preserve">les diſpoſe à concourir à la coagulation du mortier; </s> <s xml:id="echoid-s3957" xml:space="preserve">mais ſi <lb/>les ſels de la Chaux ſont en petite quantité, le ſel marin domine & </s> <s xml:id="echoid-s3958" xml:space="preserve"><lb/>fait un effet tout opoſé.</s> <s xml:id="echoid-s3959" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3960" xml:space="preserve">Quand la Chaux eſt éteinte depuis quelque tems & </s> <s xml:id="echoid-s3961" xml:space="preserve">qu’on la mêle <lb/>avec le ſable, il faut, pour en faire de bon mortier, mettre le moins <pb o="19" file="0197" n="203" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> d’eau qu’on pourra; </s> <s xml:id="echoid-s3962" xml:space="preserve">car à force de la corroyer avec des rabots il <lb/>devient liquide & </s> <s xml:id="echoid-s3963" xml:space="preserve">ſéche plus promptement que ſi il avoit été abreu-<lb/>vé davantage; </s> <s xml:id="echoid-s3964" xml:space="preserve">cependant, il faut faire attention que ſi le mortier doit <lb/>être employé avec des pierres qui s’imbibent aiſément, il faut le <lb/>faire plus liquide que quand on s’en ſert pour joindre des pierres fort <lb/>dures.</s> <s xml:id="echoid-s3965" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3966" xml:space="preserve">Il y en a qui pour faire prendre le mortier plus promptement mê-<lb/>lent de l’urine avec l’eau dont on ſe ſert pour le corroyer; </s> <s xml:id="echoid-s3967" xml:space="preserve">mais ce <lb/>que je ſais par experience, c’eſt que ſi l’on fait diſſoudre du ſel Ar-<lb/>moniac dans l’eau de Riviere, & </s> <s xml:id="echoid-s3968" xml:space="preserve">qu’on ſe ſerve enſuite de cette <lb/>eau pour corroyer de la Chaux qui auroit été faite avec de bons <lb/>cailloux, elle compoſe avec le ſable un mortier qui prend auſſi <lb/>promptement que le plâtre, ce qui peut être d’un excellent uſage dans <lb/>les pays où cette matiere eſt rare; </s> <s xml:id="echoid-s3969" xml:space="preserve">j’ajoûterai que ſi au lieu de ſable <lb/>on ſe ſervoit de la pierre pulveriſée, & </s> <s xml:id="echoid-s3970" xml:space="preserve">qui fut de la même dont on <lb/>a fait la Chaux, le mortier qui en ſeroit compoſé ſeroit incompara-<lb/>blement meilleur quand on voudroit s’en ſervir au lieu de plâtre.</s> <s xml:id="echoid-s3971" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3972" xml:space="preserve">L’on ſait que la principale qualité du mortier eſt d’unir les pierres <lb/>les unes aux autres, & </s> <s xml:id="echoid-s3973" xml:space="preserve">de ſe durcir quelque tems après avoir été <lb/>employé, pour ne faire plus qu’un même corps avec les autres ma-<lb/>teriaux. </s> <s xml:id="echoid-s3974" xml:space="preserve">Comme c’eſt la Chaux qui contribue le plus à cet effet <lb/>ſingulier, on demande pourquoi la pierre, ayant perdu dans le Four <lb/>à Chaux ſa dureté, la reprend par le moyen de l’eau & </s> <s xml:id="echoid-s3975" xml:space="preserve">du ſable? <lb/></s> <s xml:id="echoid-s3976" xml:space="preserve">Comme ceci nous offre une Diſſertation aſſés curieuſe, je vais <lb/>faire enſorte d’en donner la raiſon.</s> <s xml:id="echoid-s3977" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3978" xml:space="preserve">L’opinion des Chimiſtes eſt, que la dureté des corps vient des <lb/>ſels qui s’y trouvent répandus qui ſervent à lier leurs parties, de-<lb/>ſorte que ſelon leur ſiſtême la deſtruction qui arrive par la ſuite des <lb/>tems aux corps les plus durs ſe fait par la’perte de leur ſel qui s’é-<lb/>vapore inſenſiblement par la tranſpiration, & </s> <s xml:id="echoid-s3979" xml:space="preserve">que ſi par quelque <lb/>moyen on rend à un corps les ſels qu’il a perdu, il reprend ſa pre-<lb/>miere dureté par la réünion qui ſe fait de ſes parties. </s> <s xml:id="echoid-s3980" xml:space="preserve">Comme il y <lb/>a mille experiences qui favoriſent cette hipoteſe, je ne ferai nulle <lb/>difficulté de la recevoir avec le plus grand nombre des Phiſiciens.</s> <s xml:id="echoid-s3981" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3982" xml:space="preserve">Quand la pierre eſt brûlée par la violence du feu, il ſe fait une <lb/>évacuation de la plus grande partie de ſes ſels volatils & </s> <s xml:id="echoid-s3983" xml:space="preserve">ſulfurés qui <lb/>ſervoient de liens à ſes parties, ce qui fait qu’elle devient poreuſe <lb/>& </s> <s xml:id="echoid-s3984" xml:space="preserve">branchue: </s> <s xml:id="echoid-s3985" xml:space="preserve">or comme voilà l’état où ſe trouve la Chaux en ſor-<lb/>tant du Four, voyons preſentement ce qui peut lui rendre la du-<lb/>reté qu’elle avoit avant d’être calcinée.</s> <s xml:id="echoid-s3986" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s3987" xml:space="preserve">Quand la Chaux eſt détrempée à propos, & </s> <s xml:id="echoid-s3988" xml:space="preserve">qu’on la mêle avec <pb o="20" file="0198" n="204" rhead="LA SCIENCE DES INGENIEURS,"/> le ſable, il ſe fait une fermentation cauſée par les parties ſulfurées <lb/>qui ſont reſtées dans la Chaux, & </s> <s xml:id="echoid-s3989" xml:space="preserve">qui font ſortir du ſable une quan-<lb/>tité de ſels qui ſe mêlant avec la Chaux en rempliſſent les pores; <lb/></s> <s xml:id="echoid-s3990" xml:space="preserve">(car le ſable eſt plein de ſel volatil ainſi que les autres corps) & </s> <s xml:id="echoid-s3991" xml:space="preserve">ce <lb/>ſont ces mêmes ſels qui ſe trouvent en plus grande abondance dans <lb/>de certains ſables plûtôt qu’en d’autres qui font la difference de leur <lb/>bonne ou mauvaiſe qualité: </s> <s xml:id="echoid-s3992" xml:space="preserve">delà vient, que plus on broye la Chaux <lb/>& </s> <s xml:id="echoid-s3993" xml:space="preserve">le ſable, & </s> <s xml:id="echoid-s3994" xml:space="preserve">plus le mortier eſt bon & </s> <s xml:id="echoid-s3995" xml:space="preserve">durcit davantage quand il <lb/>eſt employé; </s> <s xml:id="echoid-s3996" xml:space="preserve">parce que le froiſſement réïteré fait ſortir du ſable <lb/>une plus grande quantité de ſel; </s> <s xml:id="echoid-s3997" xml:space="preserve">c’eſt auſſi pour cette raiſon que le <lb/>mortier, mis en œuvre tout chaud, n’eſt pas ſi bon qu’au bout de <lb/>quelques jours, parce qu’il faut un certain tems pour que les ſels vo-<lb/>latils puiſſent paſſer du ſable dans les pores de la Chaux aſin qu’il ſe <lb/>faſſe une union intime de ces deux matieres; </s> <s xml:id="echoid-s3998" xml:space="preserve">cependant il eſt à re-<lb/>marquer (comme l’experience le fait voir) que quand on laiſſe le <lb/>mor tier long-tems ſans l’employer, il ſe deſſéche, & </s> <s xml:id="echoid-s3999" xml:space="preserve">ne fait plus <lb/>de liaiſon quoiqu’on y mette de l’eau, parce que les ſels ſe ſont <lb/>évaporé s, deſorte qu’il ne reſte plus qu’une matiere ſéche, maigre <lb/>& </s> <s xml:id="echoid-s4000" xml:space="preserve">ſans onctuoſité; </s> <s xml:id="echoid-s4001" xml:space="preserve">ce qui n’arrive pas quand il eſt employé à pro-<lb/>pos, c ar alors il fait ſortir des pierres une grande quantité de ſel qui <lb/>paſſe dans les pores de la Chaux, pendant qu’elle même s’inſinuë <lb/>dans ceux de la pierre: </s> <s xml:id="echoid-s4002" xml:space="preserve">car quoiqu’il ſemble en ſe ſervant du mor-<lb/>tier qu’il n’ait plus de chaleur, la fermentation entretenuë par les <lb/>parties ſulfurées de la Chaux ſubſiſte encore très long-tems après <lb/>que la Maçonnerie eſt formée; </s> <s xml:id="echoid-s4003" xml:space="preserve">ce qui ſe remarque bien ſenſible-<lb/>ment par la dureté que le mortier acquiert de jour en jour & </s> <s xml:id="echoid-s4004" xml:space="preserve">qui <lb/>ne ceſſe de croître avec le tems par les nouveaux ſels volatils qui <lb/>paſſent de la pierre dans le mortier, par la tranſpiration que la cha-<lb/>leur dont je viens de parler y entretient; </s> <s xml:id="echoid-s4005" xml:space="preserve">& </s> <s xml:id="echoid-s4006" xml:space="preserve">c’eſt ce que l’on remar-<lb/>que dans la démolition des anciens édiſices par la peine que l’on <lb/>rencontre à ſéparer les pierres que le mortier tient uni, juſques-là <lb/>même qu’on en a moins à les rompre, qu’à les ſéparer, ſur <lb/>tout quand ce ſont des pierres un peu ſpongieuſes dans leſquelles <lb/>le mortier a pénétré. </s> <s xml:id="echoid-s4007" xml:space="preserve">Je crois même avec Philbert de Lorme, qu’on <lb/>pourroit rendre cette union de la pierre & </s> <s xml:id="echoid-s4008" xml:space="preserve">du mortier preſqu’indiſ-<lb/>ſoluble, ſi l’on faiſoit la Chaux avec des pierres de même qualité que <lb/>celles qu’on veut employer dans le Bâtiment, parce que les ſels <lb/>volatils qui en ſortiroient ſe trouvant d’une figure propre à rem-<lb/>plir les pores qui reſtent dans la Chaux par la perte qu’elle a fait des <lb/>ſiens, le mortier & </s> <s xml:id="echoid-s4009" xml:space="preserve">la pierre ne feroient plus qu’un même corps.</s> <s xml:id="echoid-s4010" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4011" xml:space="preserve">Selon ce raiſonnement on voit que les petites parties de Charbon <pb o="21" file="0199" n="205" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> de Terre, qui ſe trouvent mêlées avec de la Cendrée de Tournay, <lb/>doivent faire un merveilleux effet, quand cette Cendrée eſt battuë <lb/>avec un peu d’eau; </s> <s xml:id="echoid-s4012" xml:space="preserve">car comme ce Charbon eſt rempli de parties <lb/>ſulfurées & </s> <s xml:id="echoid-s4013" xml:space="preserve">de ſel volatil, il ſe fait un paſſage de ce ſel dans les pores <lb/>de la pierre calcinée, ce qui enſuite forme une pâte graſſe & </s> <s xml:id="echoid-s4014" xml:space="preserve">onc-<lb/>tueuſe dans laquelle il s’entretient une fermentation qui fait ſortir <lb/>de la pierre qui eſt employée avec la Cendrée, des nouveaux ſels <lb/>qui lient & </s> <s xml:id="echoid-s4015" xml:space="preserve">retiennent enſemble la Maçonnerie.</s> <s xml:id="echoid-s4016" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4017" xml:space="preserve">On croit communément que la Chaux a la vertu de brûler cer-<lb/>tains corps, parce qu’elle en occaſionne la deſtruction; </s> <s xml:id="echoid-s4018" xml:space="preserve">mais, il ne <lb/>faut pas penſer que ce ſoit la chaleur qui produiſe effectivement <lb/>cette deſtruction: </s> <s xml:id="echoid-s4019" xml:space="preserve">cela vient de ce que la Chaux faiſant tranſpirer <lb/>les ſels qui faiſoient les liens de leurs parties, dès que ces ſels ſont <lb/>évaporés, ou que la Chaux s’en eſt revêtuë, les parties de ces corps, <lb/>n’étant plus entretenuës comme auparavant, ſe deſuniſſent.</s> <s xml:id="echoid-s4020" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4021" xml:space="preserve">Comme il n’y a point de doute que ce ne ſoit la grande abon-<lb/>dance des ſels que contiennent certaines pierres qui les rend plus <lb/>propres à faire de bonne Chaux, que les autres qui en ſont beau-<lb/>coup moins chargées, cette connoiſſance fournit un moyen de fai-<lb/>re de la Chaux excellente dans les Pays même où elle a coûtume <lb/>d’être mauvaiſe comme je vais l’inſinuer.</s> <s xml:id="echoid-s4022" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4023" xml:space="preserve">Il faut avoir deux grands baſſins, l’un plus élevé que l’autre, & </s> <s xml:id="echoid-s4024" xml:space="preserve"><lb/>tous deux bien pavés & </s> <s xml:id="echoid-s4025" xml:space="preserve">les bords revêtus de Maçonnerie, on rem-<lb/>plit de Chaux le baſſin ſuperieur, & </s> <s xml:id="echoid-s4026" xml:space="preserve">on l’éteint pour la faire couler <lb/>dans l’autre, & </s> <s xml:id="echoid-s4027" xml:space="preserve">quand tout y eſt paſſé il faut jetter deſſus à peu-près <lb/>autant d’eau qu’on en a employée pour l’éteindre, enſuite la bien <lb/>broyer avec le rabot, & </s> <s xml:id="echoid-s4028" xml:space="preserve">la laiſſer repoſer pendant 24 heures: </s> <s xml:id="echoid-s4029" xml:space="preserve">com-<lb/>me elle aura eû le tems de ſe raſſéoir, on la trouvera couverte d’une <lb/>quantité d’eau de couleur verdàtre, parce qu’elle comprendra preſ-<lb/>que tous les ſels dont la Chaux étoit remplie; </s> <s xml:id="echoid-s4030" xml:space="preserve">il faut prendre toute <lb/>cette eau & </s> <s xml:id="echoid-s4031" xml:space="preserve">la verſer dans un tonneau, & </s> <s xml:id="echoid-s4032" xml:space="preserve">ôter du même baſſin la <lb/>Chaux qui s’y trouve qu’on peut regarder alors comme une matiere <lb/>qui n’eſt propre à rien: </s> <s xml:id="echoid-s4033" xml:space="preserve">on met de la nouvelle Chaux dans le baſ-<lb/>ſin ſuperieur, & </s> <s xml:id="echoid-s4034" xml:space="preserve">au lieu de l’éteindre avec de l’eau ordinaire, on <lb/>ſe ſert de celle qu’on a mis dans le tonneau, & </s> <s xml:id="echoid-s4035" xml:space="preserve">on fait couler com-<lb/>me en premier lieu cette Chaux dans l’autre baſſin; </s> <s xml:id="echoid-s4036" xml:space="preserve">ce qui fait que <lb/>comme elle comprend deux fois plus de ſel qu’elle n’en avoit na-<lb/>turellement, elle eſt incomparablement meilleure qu’elle n’eut été <lb/>ſans cette préparation. </s> <s xml:id="echoid-s4037" xml:space="preserve">S’il s’agiſſoit de quelque ouvrage de conſé-<lb/>quence fabriqué dans l’eau, on pourra, afin de rendre la Chaux en-<lb/>core meilleure, faire à l’égard de cette ſeconde, ce que l’on a fait <pb o="22" file="0200" n="206" rhead="LA SCIENCE DES INGENIEURS,"/> pour la premiere; </s> <s xml:id="echoid-s4038" xml:space="preserve">c’eſt-à-dire que l’on jettera encore dans le ſecond <lb/>baſſin autant d’eau qu’on en aura tirée d’abord, & </s> <s xml:id="echoid-s4039" xml:space="preserve">que l’on broyera <lb/>la Chaux tout de nouveau pour en faire ſortir les ſels, deſorte que <lb/>l’ayant encore laiſſée raſſéoir pendant 24 heures, on ſe ſervira de <lb/>l’eau dont elle ſera ſubmergée pour éteindre la nouvelle Chaux vive <lb/>qu’on mettra dans le premier baſſin; </s> <s xml:id="echoid-s4040" xml:space="preserve">quant à celle qui ſera reſtée <lb/>dans le ſecond, on pourra l’employer aux gros ouvrages où l’on n’y <lb/>prend pas garde de ſi pres, car elle ne ſera pas abſolument ſi deſti-<lb/>tuée de ſel qu’elle ne puiſſe encore ſervir. </s> <s xml:id="echoid-s4041" xml:space="preserve">Je connois d’habiles gens <lb/>qui ont pratiqué pluſieurs fois ce que je viens de dire, & </s> <s xml:id="echoid-s4042" xml:space="preserve">qui s’en <lb/>ſont bien trouvés; </s> <s xml:id="echoid-s4043" xml:space="preserve">ils m’ont aſſuré avoir fait par ce moyen de meil-<lb/>leure Chaux que celle de Boulogne avec la matiere du monde la <lb/>plus ingrate: </s> <s xml:id="echoid-s4044" xml:space="preserve">il eſt vrai qu’il en coûtera beaucoup plus; </s> <s xml:id="echoid-s4045" xml:space="preserve">mais l’œ-<lb/>conomie ne doit point prévaloir ſur les moyens de faire les choſes <lb/>le mieux qu’il eſt poſſible, quand il s’agit de certains ouvrages qui <lb/>demandent abſolument d’être travaillés avec précaution: </s> <s xml:id="echoid-s4046" xml:space="preserve">par exem-<lb/>ple, dans les places où la Chaux eſt ſort mauvaiſe, & </s> <s xml:id="echoid-s4047" xml:space="preserve">où l’on re-<lb/>marque que les murs de paremens des ouvrages ſe dégradent au <lb/>bout de quelques années, parce que le mortier n’a pas aſſez de <lb/>corps pour réſiſter à l’injure des ſaiſons, l’on pourroit en fabriquer <lb/>de deux ſortes; </s> <s xml:id="echoid-s4048" xml:space="preserve">l’un ſuivant les précautions que je viens de dire ſer-<lb/>vira à la conſtruction de tout ce qui eſt expoſé à l’air; </s> <s xml:id="echoid-s4049" xml:space="preserve">& </s> <s xml:id="echoid-s4050" xml:space="preserve">l’autre <lb/>fait comme à l’ordinaire pourra être employé dans le reſte de l’é-<lb/>paiſſeur des murs, & </s> <s xml:id="echoid-s4051" xml:space="preserve">aux contreforts. </s> <s xml:id="echoid-s4052" xml:space="preserve">Car enſin la néceſſité doit <lb/>rendre ingenieux. </s> <s xml:id="echoid-s4053" xml:space="preserve">Eſt-il, dit qu’à cauſe qu’on eſt dans un endroit où <lb/>les materiaux ſont mauvais, qu’on ne puiſſe faire de bonne Maçon-<lb/>nerie? </s> <s xml:id="echoid-s4054" xml:space="preserve">Je ſuis perſuadé que quand on voudra s’en donner la peine <lb/>on trouvera mille moyens de corriger la nature par le ſecours de <lb/>l’art.</s> <s xml:id="echoid-s4055" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div258" type="section" level="2" n="78"> <head xml:id="echoid-head211" xml:space="preserve">CHAPITRE SIXIE’ME.</head> <head xml:id="echoid-head212" style="it" xml:space="preserve">Des détails qui ont rapport à la Conſtruction de la Maçonnerie.</head> <p> <s xml:id="echoid-s4056" xml:space="preserve">APrès avoir enſeigné dans les Chapitres précédens le choix que <lb/>l’on devoit faire des materiaux en general, je vais faire voir <lb/>dans celui-ci les details dans leſquels il faut entrer pour juger du <lb/>prix des Ouvrages afin d’en paſſer le marché aux Entrepreneurs, <lb/>nous ne parlerons d’abord que de ce qui peut apartenir à la Maçon- <pb o="23" file="0201" n="207" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> nerie, nous réſervant de faire mention des autres détails aux en-<lb/>droits qui leur conviendrontle mieux, pour ne point embraſſer trop <lb/>d’objets à la fois, nous ne dirons rien non plus des prix, parce qu’ils <lb/>dépendent des tems & </s> <s xml:id="echoid-s4057" xml:space="preserve">des lieux ſelon que les materiaux ſont rares <lb/>ou communs, près ou éloignés: </s> <s xml:id="echoid-s4058" xml:space="preserve">circonſtances dont il ſera aiſé de <lb/>s’inſtruire dans l’occaſion, ainſi je m’attacherai plûtôt à inſinuer l’eſ-<lb/>prit du détail, qu’à donner des exemples ennuyeux qui ne ſeroient <lb/>pas d’une grande inſtruction.</s> <s xml:id="echoid-s4059" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4060" xml:space="preserve">Il faut, avant toute choſe, prendre connoiſſance des differens <lb/>terrains que la place doit occuper & </s> <s xml:id="echoid-s4061" xml:space="preserve">des matériaux qui ſont à l’uſage <lb/>du Pays: </s> <s xml:id="echoid-s4062" xml:space="preserve">s’informer des Carrieres de Chaux, de Moîlon, & </s> <s xml:id="echoid-s4063" xml:space="preserve">de Pierre <lb/>de Taille qui ſont le plus à portée, de même que des lieux d’où l’on <lb/>pourra tirer le ſable, les terres propres à faire les Briques & </s> <s xml:id="echoid-s4064" xml:space="preserve">les <lb/>Thuiles, les bois de Charpente, & </s> <s xml:id="echoid-s4065" xml:space="preserve">tout ce qu’on prévoira devoir <lb/>entrer dans la conſtruction: </s> <s xml:id="echoid-s4066" xml:space="preserve">on viſitera le tout ſoigneuſement, pour <lb/>faire de juſtes obſervations ſur leur qualité & </s> <s xml:id="echoid-s4067" xml:space="preserve">leur éloignement.</s> <s xml:id="echoid-s4068" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4069" xml:space="preserve">L’examen des differens terrains que la place doit occuper fera <lb/>connoître à peu-près quelle ſera leur nature, ſi le fond ſera bon ou <lb/>douteux, s’il faudra piloter ou non, s’il y aura des épuiſemens d’eau <lb/>à faire, & </s> <s xml:id="echoid-s4070" xml:space="preserve">pluſieurs autres circonſtances qui augmentent ſouvent ou <lb/>diminuënt les prix des ouvrages; </s> <s xml:id="echoid-s4071" xml:space="preserve">je ſais que le jugement qu’on peut <lb/>porter ſur la nature du fond eſt ſujet à erreur, & </s> <s xml:id="echoid-s4072" xml:space="preserve">qu’il n’eſt pas aiſé <lb/>de répondre de la qualité d’un terrain qui n’eſt pas foüillé & </s> <s xml:id="echoid-s4073" xml:space="preserve">qu’on <lb/>ne voit point; </s> <s xml:id="echoid-s4074" xml:space="preserve">cependant, avec un peu d’experience, on en peut <lb/>juger d’abord aſſez ſainement par le coup d’œil & </s> <s xml:id="echoid-s4075" xml:space="preserve">par la ſituation du <lb/>lieu: </s> <s xml:id="echoid-s4076" xml:space="preserve">ainſi, pour les parties qui ſe trouveront à faire ſur le Roc, ou <lb/>qu’on préſumera devoir y être fondées, on remarquera à peu-près <lb/>quel déblais de terre ou de rocaille il faudra faire pour parvenir <lb/>au fond ſolide, qu’elle eſt la nature du Roc, ſi les pierres des exca-<lb/>vations pourront ſervir au corps de la Maçonnerie, ou ſi elles ſe-<lb/>ront propres à être employées au parement, méthode cependant <lb/>qui n’eſt pas des meilleures, comme on l’a experimenté dans plu-<lb/>ſieurs places, à moins qu’on ne leur donne le tems de ſe reſſuïer, <lb/>& </s> <s xml:id="echoid-s4077" xml:space="preserve">de faire connoître leur bonne ou mauvaiſe qualité: </s> <s xml:id="echoid-s4078" xml:space="preserve">avant que de <lb/>les employer pour les endroits vaſeux ou marécageux, on connoîtra <lb/>par differentes ſondes les précautions qu’il faudra prendre pourles <lb/>fondemens, pour le pilotage, & </s> <s xml:id="echoid-s4079" xml:space="preserve">la meſure des bois.</s> <s xml:id="echoid-s4080" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4081" xml:space="preserve">On remarquera auſſi s’il y a moyen de faciliter le tranſport des <lb/>materiaux par quelque rivierre ou par un nouveau canal, & </s> <s xml:id="echoid-s4082" xml:space="preserve">s’il y <lb/>aura de la difficulté à ſe fournir des eaux neceſſaires pour la compo-<lb/>ſition des mortiers comme il arrive ſouvent dans les lieux élevés, <pb o="24" file="0202" n="208" rhead="LA SCIENCE DES INGENIEURS,"/> enfin on examinera toute choſe avec attention, & </s> <s xml:id="echoid-s4083" xml:space="preserve">on fera ſur cha-<lb/>cune les obſervations qui ſeront neceſſaires pour avoir d’avance <lb/>une idée de tout ce qui pourra entrer dans la Conſtruction de la <lb/>place.</s> <s xml:id="echoid-s4084" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4085" xml:space="preserve">Pour peu qu’on aura fait travailler dans un Pays on n’aura pas <lb/>grande difficulté à ſavoir à combien pourra revenir la toiſe cube <lb/>de Maçonnerie, j’entends celle qui ſert aux revêtemens des For-<lb/>tifications, parce qu’il n’y a qu’à s’informer des prix les plus ordi-<lb/>naires de la Chaux, du Sable, de la Brique, & </s> <s xml:id="echoid-s4086" xml:space="preserve">des differentes ſortes <lb/>de pierres qu’il faudra employer, le tout rendu ſur l’attelier, & </s> <s xml:id="echoid-s4087" xml:space="preserve">ce <lb/>qu’il en coûtera pour les préparer & </s> <s xml:id="echoid-s4088" xml:space="preserve">les mettre en œuvre: </s> <s xml:id="echoid-s4089" xml:space="preserve">ou bien <lb/>quand un Ingenieur va dans une Place où il n’a pas encore ſervi, <lb/>il lui ſera aiſé d’avoir ces ſortes d’inſtructions par ceux qui y ſont de-<lb/>puis long-tems; </s> <s xml:id="echoid-s4090" xml:space="preserve">mais ſi l’on étoit privé de ces connoiſſances, & </s> <s xml:id="echoid-s4091" xml:space="preserve">qu’il <lb/>fallut travailler dans un endroit où l’on ne ſeroit prévenu de rien, <lb/>alors il faudroit regarder les choſes de plus près, afin d’en juger ſoi-<lb/>même pour ne point s’en raporter aux Entrepreneurs & </s> <s xml:id="echoid-s4092" xml:space="preserve">à ceux qui <lb/>ont interêt que les Ingenieurs n’entrent que légerement dans quan-<lb/>tité de petits détails, qui paroiſſent d’abord ne pas mériter la peine <lb/>d’être recherchés, mais qui deviennent par la ſuite d’une grande <lb/>conſequence, ſur-tout quand il s’agit de bâtir une Place neuve, <lb/>puiſque ſans une extrême œconomie on fait de grandes dépenſes <lb/>ſuperfluës; </s> <s xml:id="echoid-s4093" xml:space="preserve">or, pour ne point tomber dans un pareil inconvenient, <lb/>voici en peu de mots à quoi on pourra avoir égard.</s> <s xml:id="echoid-s4094" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4095" xml:space="preserve">Pour commencer par le tranſport des materiaux, on ſaura qu’il <lb/>ſe régle ordinairement ſur la quantité qu’une Voiture en peut porter <lb/>& </s> <s xml:id="echoid-s4096" xml:space="preserve">des voyages qu’elle peut faire en un jour. </s> <s xml:id="echoid-s4097" xml:space="preserve">C’eſt pourquoi il faut <lb/>être prévenu qu’une Voiture attelée de trois chevaux porte environ <lb/>1500 livres; </s> <s xml:id="echoid-s4098" xml:space="preserve">ainſi dès qu’on ſaura à quelle diſtance elle eſt obligée <lb/>d’aller chercher les materiaux, leurs poids, & </s> <s xml:id="echoid-s4099" xml:space="preserve">ce qu’il en coûtera <lb/>pour leur charge, on pourra, en fixant ce qu’elle doit gagner par <lb/>jour, ſavoir à quoi reviendra le tranſport de la toiſe cube, ou le <lb/>quintal de chaque eſpece de materiaux: </s> <s xml:id="echoid-s4100" xml:space="preserve">cependant, il vaut beau-<lb/>coup mieux ne point s’embarraſſer de tous les petits détails dont cet <lb/>article eſt ſuſceptible, & </s> <s xml:id="echoid-s4101" xml:space="preserve">laiſſer à la charge de l’Entrepreneur le tranſ-<lb/>port des materiaux; </s> <s xml:id="echoid-s4102" xml:space="preserve">l’experience ayant fait voir en pluſieurs endroits, <lb/>qu’il en coûtoit la moitié moins que de le faire par œconomie, les <lb/>Entrepreneurs ayant à leur diſpoſition quantité de choſes qui coû-<lb/>teroient beaucoup plus ſi tout autre qu’eux s’en mêloit.</s> <s xml:id="echoid-s4103" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4104" xml:space="preserve">Quand il y a quelque Riviere portant Bateaux dans l’endroit où <lb/>l’on veut bâtir, les materiaux ſe tranſportent avec bien plus de fa- <pb o="25" file="0203" n="209" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> cilité & </s> <s xml:id="echoid-s4105" xml:space="preserve">moins de dépenſes: </s> <s xml:id="echoid-s4106" xml:space="preserve">il arrive même quelquefois, quand le <lb/>terrain le permet, qu’on fait faire un canal exprès pour le tranſport <lb/>des materiaux, comme on l’a pratiqué à la conſtruction du neuf <lb/>Briſack; </s> <s xml:id="echoid-s4107" xml:space="preserve">& </s> <s xml:id="echoid-s4108" xml:space="preserve">alors la dépenſe du Canal eſt répanduë generalement <lb/>ſur le prix que coûtera la Maçonnerie en y comprenant les autres <lb/>frais de la Navigation, auſſi-bien que la charge & </s> <s xml:id="echoid-s4109" xml:space="preserve">décharge des <lb/>matériaux.</s> <s xml:id="echoid-s4110" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4111" xml:space="preserve">Si on étoit dans le cas de ſe ſervir d’une Riviere ou d’un Canal <lb/>pour le tranſport, il faudroit ſavoir la charge que les Batteaux pour-<lb/>ront porter ſelon leur grandeur & </s> <s xml:id="echoid-s4112" xml:space="preserve">leur figure; </s> <s xml:id="echoid-s4113" xml:space="preserve">& </s> <s xml:id="echoid-s4114" xml:space="preserve">pour avoir quel-<lb/>que connoiſſance exacte ſur ce ſujet, je conſeille le Lecteur de voir <lb/>ce que j’en ay dit dans la dixiéme partie de mon Cours de Mathé-<lb/>matique.</s> <s xml:id="echoid-s4115" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4116" xml:space="preserve">Puiſqu’on eſt obligé de régler la charge des Voitures ſelon la pé-<lb/>ſanteur des matieres qu’elles ont à tranſporter, j’ai crû qu’il étoit à <lb/>propos de donner ici une Table qui marquât en pieds cubes le <lb/>poids des principales.</s> <s xml:id="echoid-s4117" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div259" type="section" level="2" n="79"> <head xml:id="echoid-head213" xml:space="preserve">TABLE</head> <head xml:id="echoid-head214" style="it" xml:space="preserve">DE LA PESANTEVR D’VN PIED CVBE <lb/>de pluſieurs Matieres.</head> <note position="right" xml:space="preserve">Fer # 580 liv. # Ardoiſe # 156 liv. <lb/>Cuivre jaune # 548 # Plâtre # 86 <lb/>Cuivre rouge # 648 # Pierre de Saint Leu # 115 <lb/>Plomb # 828 # Pierre de Liais # 166 <lb/>Sable de Terre # 120 # Pierre bleue de Tours # 125 <lb/>Sable fort # 124 # Marbres # 252 <lb/>Sable de Riviere # 132 # Chaux vive # 59 <lb/>Argile # 135 # Bois d’ozier # 38 <lb/>Terre graſſe # 115 # Bois d’Aulne # 37 {1/12} <lb/>Terre extraordinaire # 95 # Bois de Chêne vert # 80 <lb/>Mortier # 120 # Bois de Chêne ſec # 60 <lb/>Brique # 130 # Eau de Mer # 73 {1/2} <lb/>Thuilles # 127 # Eau Douce # 70 <lb/></note> <pb o="26" file="0204" n="210" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s4118" xml:space="preserve">Toutes ces differentes matieres peuvent péſer un peu plus ou <lb/>moins qu’on ne l’a marqué ici, ſelon le Pays où on les trouve; </s> <s xml:id="echoid-s4119" xml:space="preserve">mais <lb/>on s’eſt conformé à la péſanteur qui leur eſt la plus ordinaire.</s> <s xml:id="echoid-s4120" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4121" xml:space="preserve">Je crois en avoir aſſez dit ſur ce qui regarde le tranſport des <lb/>matériaux; </s> <s xml:id="echoid-s4122" xml:space="preserve">c’eſt pourquoi je paſſe à leur détail, en commençant <lb/>par celui de la Chaux & </s> <s xml:id="echoid-s4123" xml:space="preserve">du Sable.</s> <s xml:id="echoid-s4124" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div260" type="section" level="2" n="80"> <head xml:id="echoid-head215" style="it" xml:space="preserve">Détail de la Chaux & du Sable.</head> <p> <s xml:id="echoid-s4125" xml:space="preserve">On ſupoſe que, par epreuve faite, une toiſe cube de Pierre pro-<lb/>duit dix milliers de Chaux; </s> <s xml:id="echoid-s4126" xml:space="preserve">& </s> <s xml:id="echoid-s4127" xml:space="preserve">comme on met ordinairement huit <lb/>toiſes pour la charge d’un four, qui doivent par conſéquent pro-<lb/>duire 80 milliers, il ſera aiſé de juger ce qu’ils pouront coûter ren-<lb/>dus ſur l’attelier, en faiſant l’eſtimation du tirage de la Pierre, de ſa <lb/>Voiture au Four, de ſon arrangement dans le même Four, & </s> <s xml:id="echoid-s4128" xml:space="preserve">la <lb/>voiturer à l’endroit où on veut la mettre en œuvre.</s> <s xml:id="echoid-s4129" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4130" xml:space="preserve">A l’égard de la quantité de Chaux qui peut entrer dans une toiſe <lb/>cube de Maçonnerie tels qu’aux revêtemens des Fortifications, il <lb/>eſt aſſés difficile de la déterminer, parce qu’elle dépend de ſa bonne <lb/>ou mauvaiſe qualité, auſſi-bien que celle du Sable avec lequel elle <lb/>eſt mêlée; </s> <s xml:id="echoid-s4131" xml:space="preserve">mais, communement, il en entre douze quintaux.</s> <s xml:id="echoid-s4132" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4133" xml:space="preserve">On pourra de même juger du prix de la toiſe cube de Sable, en <lb/>faiſant l’eſtimation de ce qu’il en coûtera pour le tirage & </s> <s xml:id="echoid-s4134" xml:space="preserve">le tranſ-<lb/>port juſqu’au pied d’œuvre, ſurquoi il eſt à remarquer qu’une cer-<lb/>taine meſure de Sable peſe à peu près le double d’une pareille me-<lb/>ſure de Chaux, ce qui doit par conſequent doubler le prix de la <lb/>Voiture.</s> <s xml:id="echoid-s4135" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4136" xml:space="preserve">Il entre dans une toiſe cube de Maçonnerie environ 30 pieds <lb/>cube de Sable.</s> <s xml:id="echoid-s4137" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div261" type="section" level="2" n="81"> <head xml:id="echoid-head216" style="it" xml:space="preserve">Détail de la Brique.</head> <p> <s xml:id="echoid-s4138" xml:space="preserve">Pour ſavoir le prix du millier de Brique rendu ſur l’attelier, il fau-<lb/>dra faire l’eſtimation de ce qu’il en coûtera pour tirer la terre, la <lb/>corroyer, la mouler, la porter ſur les banquetes, l’arranger & </s> <s xml:id="echoid-s4139" xml:space="preserve">cou-<lb/>vrir de paillaiſſons, pour la faire ſécher & </s> <s xml:id="echoid-s4140" xml:space="preserve">la rouller au Four: </s> <s xml:id="echoid-s4141" xml:space="preserve">j’ou-<lb/>blie de dire qu’il faut auſſi avoir égard au Sable que l’on étend ſur <lb/>les plates-formes; </s> <s xml:id="echoid-s4142" xml:space="preserve">ce Sable doit être des meilleurs: </s> <s xml:id="echoid-s4143" xml:space="preserve">il en faut au <lb/>moins 100 Barreaux pour une Briqueterie de 450 mille, l’on verra <lb/>enſuite ce qu’il en coûtera pour la cuire, la défourner, & </s> <s xml:id="echoid-s4144" xml:space="preserve">la voiturer <lb/>juſqu’au pied d’œuvre, l’on prétend que le bois eſt meilleur pour <lb/>cuire la Brique que le Charbon de Terre, parce qu’ici il faut un <lb/>feu clair qui puiſſe pénétrer de toute part; </s> <s xml:id="echoid-s4145" xml:space="preserve">mais en récompenſe le <pb o="27" file="0205" n="211" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> Charbon de Terre eſt excellent pour les Fours à Chaux, comme <lb/>je l’ai déja dit ailleurs.</s> <s xml:id="echoid-s4146" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4147" xml:space="preserve">Dans une toiſe cube de Maçonnerie de Brique il entre quatre mille <lb/>ſix cent Briques de 8 pouces de longeur, 4 de largeur, & </s> <s xml:id="echoid-s4148" xml:space="preserve">de 2 d’é-<lb/>paiſſeur, & </s> <s xml:id="echoid-s4149" xml:space="preserve">520 dans la toiſe quarrée qui auroit une Brique d’épaiſ-<lb/>ſeur, c’eſt-à-dire 8 pouces; </s> <s xml:id="echoid-s4150" xml:space="preserve">ainſi l’on voit que le mortier occupe à <lb/>peu-près un cinquieme de la toiſe cube.</s> <s xml:id="echoid-s4151" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4152" xml:space="preserve">Une Voiture attelée de trois Chevaux porte 400 Briques, qui <lb/>péſent un peu plus de 1500 livres; </s> <s xml:id="echoid-s4153" xml:space="preserve">car, quand une Brique eſt faite <lb/>de bonne Terre & </s> <s xml:id="echoid-s4154" xml:space="preserve">bien cuite, elle péſe environ quatre livres, en <lb/>lui ſupoſant les dimentions dont j’ai parlé plus haut.</s> <s xml:id="echoid-s4155" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div262" type="section" level="2" n="82"> <head xml:id="echoid-head217" style="it" xml:space="preserve">Détail du Moîlon.</head> <p> <s xml:id="echoid-s4156" xml:space="preserve">Pour ſavoir le prix de la toiſe cube de Moîlon, il faut avoir égard <lb/>à ce qu’il en coûtera pour le déblais néceſſaire à ſa découverte, <lb/>pour le tirer de la Carriere, pour la charge & </s> <s xml:id="echoid-s4157" xml:space="preserve">décharge, pour la <lb/>Voiture & </s> <s xml:id="echoid-s4158" xml:space="preserve">la main d’œuvre.</s> <s xml:id="echoid-s4159" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4160" xml:space="preserve">Quand le Moîlon doit être façonné, pour être mis en œuvre, il <lb/>faudra voir ce qu’il en coûtera par toiſe cube, pour le picquage & </s> <s xml:id="echoid-s4161" xml:space="preserve"><lb/>ajonturage, indépendamment des autres circonſtances dont nous ve-<lb/>nons de faire mention, de même l’on pourra eſtimer la toiſe cou-<lb/>rante de Pierre de Taille en la ſupoſant, par exemple, d’un pied de <lb/>hauteur ſur 15 de lit ou environ.</s> <s xml:id="echoid-s4162" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4163" xml:space="preserve">Quand la Maçonnerie eſt compoſée de Briques & </s> <s xml:id="echoid-s4164" xml:space="preserve">de Moîlon <lb/>comme celle des revêtemens des Fortifications, le Mortier occupe <lb/>à peu-près un ſixiéme de la toiſe cube; </s> <s xml:id="echoid-s4165" xml:space="preserve">car le Moilon laiſſant moins <lb/>de vuide que la Brique, il faut moins de mortier que ſi la Maçon-<lb/>nerie étoit toute de Brique.</s> <s xml:id="echoid-s4166" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4167" xml:space="preserve">Ayant trouvé à l’aide des calculs précédens le prix de chaque <lb/>choſe en particulier, il n’y aura point de difficulté à ſavoir la dé-<lb/>penſe de la toiſe cube de Maçonnerie, dés qu’on ſaura combien <lb/>il doit y entrer de chaque eſpece de Matériaux, ce qui ſera aiſé <lb/>en faiſant dans les differens Pays où l’on ſe trouve une analiſe é-<lb/>xacte des profils les plus aprouvés & </s> <s xml:id="echoid-s4168" xml:space="preserve">les mieux dirigés.</s> <s xml:id="echoid-s4169" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4170" xml:space="preserve">L’on voit enſuite ce qu’il en pourra coûter pour chaque toiſe <lb/>cube pour le Canal, ſi on eſt obligé d’en faire un: </s> <s xml:id="echoid-s4171" xml:space="preserve">on a égard auſſi <lb/>aux faux frais auſquels les Entrepreneurs pourront être engagés pour <lb/>les épuiſemens des eaux s’il s’en rencontre, & </s> <s xml:id="echoid-s4172" xml:space="preserve">à pluſieurs autres <lb/>particularités qui doivent entrer dans la même eſtimation, & </s> <s xml:id="echoid-s4173" xml:space="preserve">moyen-<lb/>nant tous ces détails, on pourra ſavoir avant l’execution des ou- <pb o="28" file="0206" n="212" rhead="LA SCIENCE DES INGENIEURS,"/> vrages ſi les propoſitions des Entrepreneurs ſont juſtes ou non, & </s> <s xml:id="echoid-s4174" xml:space="preserve"><lb/>à quoi l’on peut s’en tenir; </s> <s xml:id="echoid-s4175" xml:space="preserve">même après que les projets ſont executés <lb/>ce qu’ils ont perdu ou gagné, & </s> <s xml:id="echoid-s4176" xml:space="preserve">quel dédommagement le Roy peut <lb/>leur accorder s’ils avoient fait un mauvais marché, ou s’il s’étoit <lb/>preſenté dans la ſuite du travail quelque difficulté qu’on n’auroit pû <lb/>prévoir, comme cela arrive aſſés ſouvent.</s> <s xml:id="echoid-s4177" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4178" xml:space="preserve">Le tems qu’on employe pour la conſtruction de la Maçonnerie eſt <lb/>encore une connoiſſance neceſſaire, ſi l’on veut ſe mettre en état <lb/>d’executer les ouvrages dans le tems preſcrit, & </s> <s xml:id="echoid-s4179" xml:space="preserve">repondre aux in-<lb/>tentions de la Cour: </s> <s xml:id="echoid-s4180" xml:space="preserve">pour cela, il faut ſavoir ce que chaque ouvrier <lb/>peut faire par jour.</s> <s xml:id="echoid-s4181" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4182" xml:space="preserve">Dans un mur épais de 10. </s> <s xml:id="echoid-s4183" xml:space="preserve">à 12 pieds, un bon Maçon peut faire <lb/>deux tiers de toiſe cube de Maçonnerie par jour, ſi le parement eſt <lb/>brut; </s> <s xml:id="echoid-s4184" xml:space="preserve">& </s> <s xml:id="echoid-s4185" xml:space="preserve">environ une demi toiſe ſeulement, s’il eſt façonné: </s> <s xml:id="echoid-s4186" xml:space="preserve">mais pour <lb/>que cette régle ait lieu, il faut que l’ouvrier ſoit des meilleurs, & </s> <s xml:id="echoid-s4187" xml:space="preserve"><lb/>qu’il ne perde pas un moment de tems; </s> <s xml:id="echoid-s4188" xml:space="preserve">ainſi l’on peut réduire le <lb/>travail à cinq huitiémes dans le parement brut, & </s> <s xml:id="echoid-s4189" xml:space="preserve">à trois huitiémes <lb/>dans le parement façonné; </s> <s xml:id="echoid-s4190" xml:space="preserve">chaque Maçon doit avoir deux Ma-<lb/>nœuvres pour le ſervir, quand les matériaux ſont éloignés de 15 à <lb/>20 toiſes de l’ouvrage.</s> <s xml:id="echoid-s4191" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4192" xml:space="preserve">Dans un mur de deux pieds d’épaiſſeur, le même Maçon peut <lb/>faire aiſément une toiſe quarrée par jour, en s’aſſujetiſſant aux <lb/>échaffaudages.</s> <s xml:id="echoid-s4193" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4194" xml:space="preserve">Pour dire auſſi quelque choſe ſur la maniere judicieuſe avec la-<lb/>quelle un Ingenieur doit agir au ſujet des particuliers, dont les terres <lb/>ſont compriſes dans l’étenduë des ouvrages d’une Place neuve: <lb/></s> <s xml:id="echoid-s4195" xml:space="preserve">voici ce qui m’a parû de plus raiſonnable.</s> <s xml:id="echoid-s4196" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4197" xml:space="preserve">Pour les Particuliers dont les héritages doivent être occupés par <lb/>les Fortifications, on ne peut avoir trop d’attention pour leur ren-<lb/>dre la juſtice qui leur eſt dûe, & </s> <s xml:id="echoid-s4198" xml:space="preserve">pour les dédommager en quelque <lb/>façon du chagrin de perdre leurs biens; </s> <s xml:id="echoid-s4199" xml:space="preserve">ainſi il ne faut point agir <lb/>en toute rigueur avec eux, mais bien régler l’eſtimation, de ma-<lb/>niere que le Roy n’y ſoit point lezé, & </s> <s xml:id="echoid-s4200" xml:space="preserve">que le Particulier n’y perde <lb/>rien: </s> <s xml:id="echoid-s4201" xml:space="preserve">pour cet effet, après avoir bien examiné & </s> <s xml:id="echoid-s4202" xml:space="preserve">marqué tout ce <lb/>qui doit être pris de ces heritages, il faut en faire un deſſein diſ-<lb/>tingué par des côtes qui déſignent ce qui apartient à chacun, & </s> <s xml:id="echoid-s4203" xml:space="preserve">qui <lb/>ſoient raportées à la marge avec le nom du Particulier; </s> <s xml:id="echoid-s4204" xml:space="preserve">après toute-<lb/>fois qu’il aura été juſtifié par titre ou poſſeſſion ſuffiſante que cet <lb/>héritage lui apartient. </s> <s xml:id="echoid-s4205" xml:space="preserve">On procede enſuite à l’eſtimation de la va-<lb/>leur de ces biens, ce qui ſe fait pardevant l’Ingenieur, le Commiſ-<lb/>ſaire des Guerres, & </s> <s xml:id="echoid-s4206" xml:space="preserve">les Magiſtrats de la Ville ou Communauté, qui <pb o="29" file="0207" n="213" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> choiſiſſent chacun de leur côté des Experts pour évaluer, ſous leur <lb/>ſerment, le prix de chaque choſe, dont les Magiſtrats & </s> <s xml:id="echoid-s4207" xml:space="preserve">les intereſſés <lb/>donnent acte: </s> <s xml:id="echoid-s4208" xml:space="preserve">après l’eſtimation faite, on ſpecifie d’abord les Mai-<lb/>ſons, Jardins, Prés, Champs, & </s> <s xml:id="echoid-s4209" xml:space="preserve">Vergers, chacun ſuivant ſa juſte <lb/>valeur, & </s> <s xml:id="echoid-s4210" xml:space="preserve">on en dreſſe un acte dans lequel ſont raportés les noms <lb/>des Propriétaires, la quantité des arpens, ou journaux, & </s> <s xml:id="echoid-s4211" xml:space="preserve">le prix <lb/>auquel chaque héritage eſt évalué: </s> <s xml:id="echoid-s4212" xml:space="preserve">on dreſſe un autre acte de la <lb/>quantité des terres qui ont été ou ſeront renduës inutiles & </s> <s xml:id="echoid-s4213" xml:space="preserve">miſes <lb/>hors de’valeur par les Gazons & </s> <s xml:id="echoid-s4214" xml:space="preserve">Briques que l’on en tirera, ou par le <lb/>raſement ou comblement de telle & </s> <s xml:id="echoid-s4215" xml:space="preserve">telle partie: </s> <s xml:id="echoid-s4216" xml:space="preserve">on en fait encore <lb/>un troiſiéme qui contient la quantité des Terres qui étoient ſemen-<lb/>cées de ſeigle, froment, orge, & </s> <s xml:id="echoid-s4217" xml:space="preserve">avoine, &</s> <s xml:id="echoid-s4218" xml:space="preserve">c. </s> <s xml:id="echoid-s4219" xml:space="preserve">avec l’eſtimation de <lb/>chacun de ſes fruits ſuivant le prix de l’année courante; </s> <s xml:id="echoid-s4220" xml:space="preserve">le tout cer-<lb/>tifié par les Maire & </s> <s xml:id="echoid-s4221" xml:space="preserve">Jurés du lieu, par les Experts, l’Ingenieur, & </s> <s xml:id="echoid-s4222" xml:space="preserve"><lb/>le Commiſſaire des Guerres: </s> <s xml:id="echoid-s4223" xml:space="preserve">enfin, tous ces Etats étant reglés, on <lb/>les envoye à l’Intendant de la Province, qui, en conſéquence des or-<lb/>dres de la Cour, les renvoye au Tréſorier de la Place, & </s> <s xml:id="echoid-s4224" xml:space="preserve">en ordon-<lb/>ne le payement, que chaque Particulier ſigne en marge à côté de <lb/>l’article qui le concerne & </s> <s xml:id="echoid-s4225" xml:space="preserve">déclare avoir reçû en preſence du Com-<lb/>miſſaire des Guerres.</s> <s xml:id="echoid-s4226" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div263" type="section" level="2" n="83"> <head xml:id="echoid-head218" xml:space="preserve">CHAPITRE SEPTIE’ME.</head> <head xml:id="echoid-head219" style="it" xml:space="preserve">Qui comprend pluſieurs Inſtructions ſur l’établiſſement & <lb/>la conduite des Travaux.</head> <p> <s xml:id="echoid-s4227" xml:space="preserve">LA conduite des grands Travaux embraſſe tant de choſes à la <lb/>fois, qu’on peut dire qu’il n’apartient qu’aux Ingenieurs du pre-<lb/>mier ordre d’entrer dans tous les détails ſans perdre de vûe les ſu-<lb/>jets eſſentiels du projet que l’on veut executer. </s> <s xml:id="echoid-s4228" xml:space="preserve">C’étoit une des <lb/>grandes qualités de Mr. </s> <s xml:id="echoid-s4229" xml:space="preserve">le Marêchal de Vauban; </s> <s xml:id="echoid-s4230" xml:space="preserve">& </s> <s xml:id="echoid-s4231" xml:space="preserve">on ne peut voir <lb/>fans étonnement, qu’occupé ſans ceſſe (comme il l’étoit) à tout ce qui <lb/>pouvoit contribuer à la ſûreté de l’Etat & </s> <s xml:id="echoid-s4232" xml:space="preserve">au bonheur des Peuples, <lb/>il ait pù deſcendre à l’examen d’une infinité de petits ſujets qui pa-<lb/>roiſſoient ne pas mériter ſon attention: </s> <s xml:id="echoid-s4233" xml:space="preserve">mais, les genies ſuperieurs <lb/>n’aprehendent jamais de ſe dégrader, leur conduite eſt toûjours <lb/>juſtifiée par le fruit que l’on tire de leurs réflections, en effet on <lb/>ne peut rien de plus ſage & </s> <s xml:id="echoid-s4234" xml:space="preserve">de mieux entendu que les réglemens <lb/>que ce grand homme nous a laiſſés ſur quantité de choſes, parti- <pb o="30" file="0208" n="214" rhead="LA SCIENCE DES INGENIEURS,"/> culierement ſur l’ordre & </s> <s xml:id="echoid-s4235" xml:space="preserve">l’arrangement que l’on doit ſuivre dans la <lb/>Conſtruction des Fortifications; </s> <s xml:id="echoid-s4236" xml:space="preserve">& </s> <s xml:id="echoid-s4237" xml:space="preserve">comme je me ſuis propoſé d’en <lb/>parler dans ce Chapitre, j’aurai recours à ſes écrits pour répondre <lb/>à l’eſtime que le Public fait de tout ce qui vient de lui.</s> <s xml:id="echoid-s4238" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4239" xml:space="preserve">Les Fortifications, dit-il, ſe font ordinairement par des entre-<lb/>priſes generales ou particulieres, ou par détail ou par courvées <lb/>impoſées ſur le Pays, & </s> <s xml:id="echoid-s4240" xml:space="preserve">le plus ſouvent par un compoſé de toutes <lb/>ces manieres enſemble.</s> <s xml:id="echoid-s4241" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4242" xml:space="preserve">Quand on pourra trouver des Entrepreneurs ſolvables, & </s> <s xml:id="echoid-s4243" xml:space="preserve">de ca-<lb/>pacité à pouvoir embraſſer une entrepriſe generale, on fera bien <lb/>de traiter avec eux: </s> <s xml:id="echoid-s4244" xml:space="preserve">mais il eſt très-rare de rencontrer des têtes <lb/>aſſés fortes pour ſoûtenir un fardeau auſſi péſant que celui d’une en-<lb/>trepriſe generale; </s> <s xml:id="echoid-s4245" xml:space="preserve">car la précipitation avec laquelle on fait ordinai-<lb/>rement les ouvrages, & </s> <s xml:id="echoid-s4246" xml:space="preserve">la durée de telles entrepriſes, réduiſent ſou-<lb/>vent l’Entrepreneur à ne ſavoir plus où il en eſt: </s> <s xml:id="echoid-s4247" xml:space="preserve">c’eſt pourquoi il <lb/>vaudroit mieux s’en tenir aux entrepriſes particulieres, qui peuvent <lb/>s’achever en peu de tems.</s> <s xml:id="echoid-s4248" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4249" xml:space="preserve">On doit auſſi remarquer, que quand il s’agit de paſſer des marchés <lb/>pour des ouvrages conſiderables, il eſt bon de le faire dans les for-<lb/>mes, mais non pas de les donner à tous ceux qui ſe preſenteront <lb/>pour les prendre au moindre prix; </s> <s xml:id="echoid-s4250" xml:space="preserve">car il faut non-ſeulement exa-<lb/>miner ſi les Entrepreneurs ont aſſés de bien pour répondre des avan-<lb/>ces qu’on ſera obligé de leur faire, mais encore s’ils ont aſſés de <lb/>lumieres pour s’acquitter de l’entrepriſe: </s> <s xml:id="echoid-s4251" xml:space="preserve">il faut leur accorder à <lb/>des conditions raiſonnables, ſans pouſſer les miſes aux rabais à plus <lb/>bas prix qu’elles ne doivent être; </s> <s xml:id="echoid-s4252" xml:space="preserve">car ſi l’entrepriſe eſt un peu groſſe, <lb/>& </s> <s xml:id="echoid-s4253" xml:space="preserve">qu’on la donne à des pauvres gens, ou à des ignorans, ils la pren-<lb/>dront inconſidéremment à tel prix qu’on voudra, dans l’eſperance <lb/>de profiter de façon ou d’autre: </s> <s xml:id="echoid-s4254" xml:space="preserve">mais outre qu’on n’y trouvera pas <lb/>de ſureté, quand on viendra à l’execution, on doit s’attendre qu’ils <lb/>tireront partie du profit autant qu’ils pourront, & </s> <s xml:id="echoid-s4255" xml:space="preserve">d’un autre côté <lb/>mettront tous les ouvrages en confuſion; </s> <s xml:id="echoid-s4256" xml:space="preserve">après quoi la tête leur <lb/>tournant ils donneront du nez en terre, ou abandonneront tout <lb/>d’eux-même ſi on ne les prévient: </s> <s xml:id="echoid-s4257" xml:space="preserve">or ſi malheureuſement cela arri-<lb/>ve, les travaux languiſſent & </s> <s xml:id="echoid-s4258" xml:space="preserve">ne s’avancent qu’avec une lenteur in-<lb/>ſuportable, tout eſt en conſuſion, les marchés n’ont plus de crédit <lb/>ni de confiance, les nouveaux Entrepreneurs qu’on ſeroit obligé de <lb/>prendre ne veulent accepter les Ouvrages qu’à un prix exhorbitant, <lb/>ceux qui doivent être achevés en un an à peine le peuvent être en <lb/>deux, les Ouvriers étant mal payés déſertent, il ne s’en preſente <lb/>qu’un petit nombre, tout cela occaſionne des peines infinies aux <pb o="31" file="0209" n="215" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> Ingenieurs, qui ne peuvent ſans beaucoup de difficulté remettre <lb/>les choſes ſur le bon pied; </s> <s xml:id="echoid-s4259" xml:space="preserve">d’où l’on peut conclure, qu’il n’eſt rien <lb/>de ſi pernicieux que ce prétendu bon marché: </s> <s xml:id="echoid-s4260" xml:space="preserve">ainſi, on ne peut trop <lb/>deſabuſer ceux qui mettent toute leur aplication à faire des marchés <lb/>au plus bas prix qu’ils peuvent, ſans examiner les ſuites, & </s> <s xml:id="echoid-s4261" xml:space="preserve">la poſſi-<lb/>bilité de pouvoir les executer.</s> <s xml:id="echoid-s4262" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4263" xml:space="preserve">Il faut toûjours éviter les details inutiles & </s> <s xml:id="echoid-s4264" xml:space="preserve">embaraſſans, ſur-tout <lb/>les ouvrages à journées, à cauſe de la confuſion & </s> <s xml:id="echoid-s4265" xml:space="preserve">des friponneries <lb/>qui s’y commettent; </s> <s xml:id="echoid-s4266" xml:space="preserve">car l’ouvrier qui eſt aſſuré de ſon gain ne ſe <lb/>preſſe jamais, au lieu que celui qui ne gagne qu’autant qu’il travaille <lb/>n’a beſoin d’autre chaſſavant que ſon propre intereſt: </s> <s xml:id="echoid-s4267" xml:space="preserve">il eſt éga-<lb/>lement de conſequence d’éviter tous les ouvrages à courvées qui <lb/>demandent quelque façon & </s> <s xml:id="echoid-s4268" xml:space="preserve">de la promptitude, attendu que la <lb/>diligence & </s> <s xml:id="echoid-s4269" xml:space="preserve">le ſavoir ne ſe rencontrent jamais parmi des gens qui <lb/>travaillent par force, & </s> <s xml:id="echoid-s4270" xml:space="preserve">qui ne tâchent qu’à couler le tems; </s> <s xml:id="echoid-s4271" xml:space="preserve">mais <lb/>quand on ſera obligé de s’en ſervir au remuëment des Terres, il <lb/>leur faudra impoſer la quantité qu’on leur voudra faire remuer, & </s> <s xml:id="echoid-s4272" xml:space="preserve"><lb/>la départir par communauté, moyennant quoi ils traiteront les uns <lb/>avec les autres, ou ils s’accommoderont avec l’Entrepreneur pour <lb/>en pouvoir venir à bout, & </s> <s xml:id="echoid-s4273" xml:space="preserve">de quelque maniere que cela ſe faſſe, il <lb/>en faudra prendre connoiſſance, & </s> <s xml:id="echoid-s4274" xml:space="preserve">charitablement voir ſi ceux avec <lb/>qui ils traiteront ne ſe trompent point ſur le prix ou ſur le meſurage <lb/>& </s> <s xml:id="echoid-s4275" xml:space="preserve">ne leur vendent trop cherement leur peines; </s> <s xml:id="echoid-s4276" xml:space="preserve">mais tout bien con-<lb/>ſideré cette maniere de travailler ne devroit être miſe en uſage <lb/>que pour des Charrois ou des Ouvrages fort groſſiers & </s> <s xml:id="echoid-s4277" xml:space="preserve">toûjours <lb/>le moins qu’on pourra.</s> <s xml:id="echoid-s4278" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4279" xml:space="preserve">Quand on fera le département des ouvrages aux gens employés, <lb/>il faudra bien prendre garde d’apliquer chacun à celui qui lui con-<lb/>viendra le mieux, & </s> <s xml:id="echoid-s4280" xml:space="preserve">ſur-tout tenir pour maxime d’avoir toûjours <lb/>un homme fidele & </s> <s xml:id="echoid-s4281" xml:space="preserve">intelligent dans la Maçonnerie, qui ne perde ja-<lb/>mais de vûë la main des Maçons, car la plûpart manquent extrê-<lb/>mement de ſoin dans l’arrangement des matériaux, ſoit par négli-<lb/>gence, ignorance, ou friponnerie, ce qui n’arrive que trop quand <lb/>ils ne ſont pas éclairés de quelqu’un qui les tienne en crainte: </s> <s xml:id="echoid-s4282" xml:space="preserve">c’eſt <lb/>auſſi pour certe raiſon qu’on ne doit jamais ſouffrir qu’ils travaillent <lb/>aux heures induës, ni ſans la preſence de ceux à qui l’on aura com-<lb/>mis le ſoin de les obſerver, n’y ayant rien de ſi pernicieux dans la <lb/>conduite des travaux, que ces ſortes de negligences.</s> <s xml:id="echoid-s4283" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4284" xml:space="preserve">Tous ceux qui ont de l’experience dans l’art de bâtir n’oublient <lb/>jamais de ſpecifier cette condition dans les marchés qu’ils en font, <lb/>non plus que celle de ne point faire les mortiers ſans la preſence <pb o="32" file="0210" n="216" rhead="LA SCIENCE DES INGENIEURS,"/> d’un Commis qui les faſſe dozer & </s> <s xml:id="echoid-s4285" xml:space="preserve">conditionner ſelon les devis, <lb/>& </s> <s xml:id="echoid-s4286" xml:space="preserve">qui prenne garde qu’on ne les employe qu’après être refroidis; <lb/></s> <s xml:id="echoid-s4287" xml:space="preserve">ce qu’il ne faut point négliger, puiſque de la main d’œuvre, & </s> <s xml:id="echoid-s4288" xml:space="preserve">de <lb/>la qualité du mortier, dépend abſolument celle de la Maçon-<lb/>nerie.</s> <s xml:id="echoid-s4289" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4290" xml:space="preserve">Il faut neceſſairement un certain nombre d’Inſpecteurs & </s> <s xml:id="echoid-s4291" xml:space="preserve">de <lb/>Chaſſavants ſur les ouvrages, puiſque rien n’eſt plus important que <lb/>d’avoir des Argus fideles ſur la main des Ouvriers, qui obſervent <lb/>leurs actions & </s> <s xml:id="echoid-s4292" xml:space="preserve">les faſſent diligenter; </s> <s xml:id="echoid-s4293" xml:space="preserve">mais il faut les connoître & </s> <s xml:id="echoid-s4294" xml:space="preserve"><lb/>les bien choiſir, être auſſi prompt à récompenſer ceux qui font bien, <lb/>qu’à renvoyer ceux qui manqueront d’aplication & </s> <s xml:id="echoid-s4295" xml:space="preserve">de fidelité: </s> <s xml:id="echoid-s4296" xml:space="preserve">par <lb/>exemple, j’en voudrois un pour les Maçons, un autre pour les <lb/>Terraſſiers, un autre pour les Voitures, un autre pour la décharge <lb/>des Materiaux: </s> <s xml:id="echoid-s4297" xml:space="preserve">s’il arrivoit que le nombre des Ouvriers de même <lb/>eſpece fut fort grand, il faut mettre un homme pour veiller à la <lb/>conduite de cent autres, n’étant guerre poſſible qu’il puiſſe en éclai-<lb/>rer davantage, ſur quoi l’on remarquera qu’il en faut beaucoup plus <lb/>dans les ouvrages qui ſe font en détail, que ſur ceux qui ſe font <lb/>par entrepriſes, puiſque pour ceux-ci il ſuffit d’en avoir à la Ma-<lb/>çonnerie & </s> <s xml:id="echoid-s4298" xml:space="preserve">au remuëment des Terres, au lieu qu’aux autres il en <lb/>faut de neceſſité ſur tous les differens ouvrages; </s> <s xml:id="echoid-s4299" xml:space="preserve">car il ne faut pas <lb/>penſer que deux ou trois hommes puiſſent ſuffire pour conduire <lb/>1000 ou 1200 Ouvriers, qui étant diviſés en je ne ſçai combien <lb/>d’ouvrages differens, il eſt comme impoſſible qu’il ne ſe commette <lb/>une infinité d’abus & </s> <s xml:id="echoid-s4300" xml:space="preserve">de négligences: </s> <s xml:id="echoid-s4301" xml:space="preserve">ſi on n’y aporte une attention <lb/>continuelle, il ſe fait beaucoup de dépenſes ſuperfluës, les Ouvra-<lb/>ges ſont mal façonnés, deſorte que ce qui ſe fait mal-à-propos <lb/>excede au centuple la dépenſe des apointemens que l’on croit epar-<lb/>gner en employant trois ou quatre hommes de moins qu’il n’en au-<lb/>roit fallu: </s> <s xml:id="echoid-s4302" xml:space="preserve">ce n’eſt pas ici une exageration, & </s> <s xml:id="echoid-s4303" xml:space="preserve">je m’aſſure qu’il n’y a <lb/>perſonne, qui aye fait un peu travailler, qui ne demeure d’accord <lb/>que quatre hommes bien obſervés font plus d’ouvrage que ſix <lb/>autres qu’on abandonneroit à leur propre conduite.</s> <s xml:id="echoid-s4304" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4305" xml:space="preserve">Une précaution, la plus neceſſaire de toutes celles que l’on peut <lb/>preſcrire pour la bonne conduite des Travaux, eſt de ne commen-<lb/>cer jamais aucun Ouvrage que l’on n’aye fait auparavant les amas <lb/>de materiaux & </s> <s xml:id="echoid-s4306" xml:space="preserve">de tout ce qui eſt neceſſaire pour une prompte <lb/>execution; </s> <s xml:id="echoid-s4307" xml:space="preserve">ces materiaux doivent être placés près des lieux où il <lb/>faut les employer, prenant garde cependant qu’ils n’embaraſſent <lb/>ni les Voitures ni les Ouvriers; </s> <s xml:id="echoid-s4308" xml:space="preserve">rien n’eſt ſi neceſſaire à la For-<lb/>tification que la diligence, ni rien ne lui eſt ſi opoſé que la grande <pb o="33" file="0211" n="217" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> précipitation avec laquelle on les commence, le plus ſouvent ſans <lb/>avoir fait proviſion des materiaux dont on peut avoir beſoin, ni <lb/>ſans être aſſuré de la quantité d’Ouvriers qu’on y voudra employer, <lb/>d’autant que de cet empreſſement il arrive qu’avant qu’ils ſoient à <lb/>moitié faits, on manque de je ne ſçai combien de choſes, qui cauſent <lb/>toujours un retar dement dangereux, & </s> <s xml:id="echoid-s4309" xml:space="preserve">une augmentation de dépenſe <lb/>conſidérable par les ſecours extraordinaires qu’on eſt obligé d’em-<lb/>prunter ailleurs, & </s> <s xml:id="echoid-s4310" xml:space="preserve">qu’on paye quelquefois bien cher; </s> <s xml:id="echoid-s4311" xml:space="preserve">ſans compter <lb/>les dommages que le Pays ſouffre de ce que l’on eſt contraint d’exiger <lb/>des courvées & </s> <s xml:id="echoid-s4312" xml:space="preserve">voitures, dans le tems même que les Payſans ſont <lb/>occupés à leur recolte: </s> <s xml:id="echoid-s4313" xml:space="preserve">c’eſt ce qui nous fait encore répeter, qu’on <lb/>ne doit jamais commencer un Ouvrage, ſans avoir bien pris des me-<lb/>ſures pour la fourniture des materiaux, & </s> <s xml:id="echoid-s4314" xml:space="preserve">ſans en avoir fait un amas <lb/>ſi conſidérable, que la quantité d’Ouvriers qu’on aura réſolu d’em-<lb/>ployer n’en puiſſe jamais manquer, ce qui doit être obſervé d’au-<lb/>tant plus exactement, que rien n’eſt ſi dangereux pour une Place que <lb/>la lenteur de ces Ouvrages, attendu que juſqu’à ce qu’ils ayent ac-<lb/>quis leur perfection, elle eſt toûjours en péril & </s> <s xml:id="echoid-s4315" xml:space="preserve">conſidérablement <lb/>affoiblie par la propre imperfection de ceux que l’on a bâti, par <lb/>l’embarras des materiaux répandus à l’entour, par l’ouverture de <lb/>ſes chemins couverts pour faire paſſer les Chariots, par le comble-<lb/>ment des Foſſés, accidens toûjours inſéparables des Travaux im-<lb/>parfaits, d’où s’enſuit que juſqu’à ce qu’une piece, telle qu’elle ſoit, <lb/>ait acquis ſon entiere perfection, elle eſt toûjours contre la Place; <lb/></s> <s xml:id="echoid-s4316" xml:space="preserve">c’eſt-à-dire, plûtôt en état de lui nuire que de ſervir à ſa deffenſe: </s> <s xml:id="echoid-s4317" xml:space="preserve"><lb/>ſituation malheureuſe & </s> <s xml:id="echoid-s4318" xml:space="preserve">qui devroit faire trembler ceux qui ont la <lb/>conduite des Ouvrages qui ſont mal en train, & </s> <s xml:id="echoid-s4319" xml:space="preserve">qui languiſſent faute <lb/>d’avoir pris des meſures aſſés juſtes pour les diligenter, principale-<lb/>ment dans un tems de Guerre, où l’ennemi peut à tout moment <lb/>former des entrepriſes; </s> <s xml:id="echoid-s4320" xml:space="preserve">il n’y a rien de ſi commun dans l’hiſtoire des <lb/>Guerres paſſées que la perte des Places qui ont été ſurpriſes, ou <lb/>que l’on a été contraint d’abandonner, avant que leurs Fortifica-<lb/>tions fuſſent en état de deffence.</s> <s xml:id="echoid-s4321" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4322" xml:space="preserve">Soit que l’on conſtruiſe une Place neuve, ou qu’on en fortifie <lb/>d’autres pour les mettre plus en état deffenſe qu’elles ne le ſont, <lb/>on doit toûjours commencer par les chemins couverts, enſuite par <lb/>les Ouvrages les plus avancés afin d’avoir au moins une barriere <lb/>pour arrêter l’ennemi, cette précaution eſt ſur-tout neceſſaire quand <lb/>on eſt obligé de bâtir de nouveau quelque enceinte, ou de démo-<lb/>lir des déhors pour leur donner une conſtruction plus avantageuſe <lb/>que celle qu’ils avoient, l’ouverture d’une Place étant toûjours dan- <pb o="34" file="0212" n="218" rhead="LA SCIENCE DES INGENIEURS,"/> gereuſe dans la Paix même la plus profonde: </s> <s xml:id="echoid-s4323" xml:space="preserve">l’art de fortifier eſt <lb/>ſuſceptible d’une infinité d’attentions qu’on ne peut négliger, ſans <lb/>qu’elles ne tirent à de grandes conſequences.</s> <s xml:id="echoid-s4324" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4325" xml:space="preserve">Une attention qu’on doit avoir & </s> <s xml:id="echoid-s4326" xml:space="preserve">qui eſt eſſentielle, continuë Mr. </s> <s xml:id="echoid-s4327" xml:space="preserve">le <lb/>Marêchal de Vauban, eſt de donner les employs ſuivant la neceſſité <lb/>des Ouvrages & </s> <s xml:id="echoid-s4328" xml:space="preserve">la capacité d’un chacun, afin de n’y employer que <lb/>des gens utiles & </s> <s xml:id="echoid-s4329" xml:space="preserve">neceſſaires, & </s> <s xml:id="echoid-s4330" xml:space="preserve">de ne charger perſonne de ce <lb/>qu’il ne ſait pas, ni de plus qu’il ne ſait faire: </s> <s xml:id="echoid-s4331" xml:space="preserve">ce deffaut, où l’on ne <lb/>prend pas garde, étant ordinairement l’origine & </s> <s xml:id="echoid-s4332" xml:space="preserve">la ſource de tous <lb/>les deſordres dans la conduite des Fortifications.</s> <s xml:id="echoid-s4333" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4334" xml:space="preserve">Il eſt très conſtant que ce qui nuit le plus à l’œconomie, & </s> <s xml:id="echoid-s4335" xml:space="preserve">même <lb/>à l’avancement des Ouvrages, eſt le renouvellement frequent que <lb/>l’on fait de ceux qui en ont les principaux ſoins, ſpecialement des <lb/>Ingenieurs; </s> <s xml:id="echoid-s4336" xml:space="preserve">vû que de ce changement il arrive que perſonne ne <lb/>s’inſtruit jamais à fond, & </s> <s xml:id="echoid-s4337" xml:space="preserve">l’on y eſt toûjours nouveau; </s> <s xml:id="echoid-s4338" xml:space="preserve">que l’on <lb/>ne connoît qu’imparfaitement la qualité des materiaux, leur prix, <lb/>& </s> <s xml:id="echoid-s4339" xml:space="preserve">la capacité des Ouvriers; </s> <s xml:id="echoid-s4340" xml:space="preserve">que l’on ne ſait, ni les moyens de faire <lb/>les Voitures, ni de quelle maniere s’y prendre pour établir ún bon <lb/>ordre: </s> <s xml:id="echoid-s4341" xml:space="preserve">cependant, ce ſont des parties qu’il faut neceſſairement ſa-<lb/>voir, & </s> <s xml:id="echoid-s4342" xml:space="preserve">qui ne s’aprennent qu’avec du tems; </s> <s xml:id="echoid-s4343" xml:space="preserve">de plus j’ôſe bien <lb/>dire, & </s> <s xml:id="echoid-s4344" xml:space="preserve">il n’eſt que trop certain, que quelque ſoin que les gens pren-<lb/>nent à ſe rendre ſavans dans ce métier, le Souverain, aux dépens <lb/>de qui on l’aprend, en paye toûjours chérement l’apprentiſſage. <lb/></s> <s xml:id="echoid-s4345" xml:space="preserve">Car s’il eſt vrai (comme l’on n’en peut pas douter) que dans tous <lb/>les commencemens des grands Ouvrages il eſt impoſſible aux plus <lb/>intelligens même, quelque application qu’ils y apportent, d’empê-<lb/>cher que la dépenſe n’en excede toûjours le juſte prix d’un cinquié-<lb/>me ou d’un ſixiéme; </s> <s xml:id="echoid-s4346" xml:space="preserve">que doit-il arriver aux Travaux de Places, <lb/>où l’on change tous les ans d’Ingenieurs, & </s> <s xml:id="echoid-s4347" xml:space="preserve">où jamais perſonne n’a <lb/>le tems d’apprendre ce qu’il doit ſavoir. </s> <s xml:id="echoid-s4348" xml:space="preserve">Certainement, il n’en <lb/>peut proceder que des deſſeins mal executés & </s> <s xml:id="echoid-s4349" xml:space="preserve">des redoublemens <lb/>de dépenſes effroyables, à quoi il n’y a d’autre remede que de bien <lb/>choiſir une fois pour tout les gens qu’on y voudra employer, ſe <lb/>donner patience qu’ils s’y ſoient bien inſtruits, & </s> <s xml:id="echoid-s4350" xml:space="preserve">les perpetuer <lb/>après dans l’employ tant qu’on aura beſoin d’eux & </s> <s xml:id="echoid-s4351" xml:space="preserve">qu’ils s’y con-<lb/>duiront bien.</s> <s xml:id="echoid-s4352" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4353" xml:space="preserve">F’ ai tiré ce Diſcours mot pour mot, d’un petit Ouvrage de Mr. </s> <s xml:id="echoid-s4354" xml:space="preserve">de <lb/>Vauban, qui a pour Titre, Le Directeur General des Fortifications.</s> <s xml:id="echoid-s4355" xml:space="preserve"/> </p> <pb o="35" file="0213" n="219" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> </div> <div xml:id="echoid-div264" type="section" level="2" n="84"> <head xml:id="echoid-head220" xml:space="preserve">CHAPITRE HUITIE’ME.</head> <head xml:id="echoid-head221" style="it" xml:space="preserve">Du Tranſport & Rémuëment des Terres.</head> <p> <s xml:id="echoid-s4356" xml:space="preserve">LA foüille des terres & </s> <s xml:id="echoid-s4357" xml:space="preserve">leur tranſport font un objet ſi conſidé-<lb/>rable dans les grands Travaux, qu’on peut dire qu’il n’y a point <lb/>de partie qui demande plus d’attention & </s> <s xml:id="echoid-s4358" xml:space="preserve">un détail plus recherché <lb/>pour en bien regler le prix ſelon leur qualité & </s> <s xml:id="echoid-s4359" xml:space="preserve">la diſtance où il <lb/>faut les porter; </s> <s xml:id="echoid-s4360" xml:space="preserve">car, pour peu que l’eſtimation n’en ſoit pas bien <lb/>entenduë & </s> <s xml:id="echoid-s4361" xml:space="preserve">les relais bien ordonnés, on tombe dans des excès de <lb/>dépenſes, la confuſion & </s> <s xml:id="echoid-s4362" xml:space="preserve">le déſordre regnent par tout, les Travail-<lb/>leurs ſe plaignent, les Entrepreneurs murmurent, & </s> <s xml:id="echoid-s4363" xml:space="preserve">ſouvent le mal <lb/>devient ſi grand, que l’Ingenieur tout habile qu’il puiſſe être eſt fort <lb/>embarraſſé du parti qu’il doit prendre. </s> <s xml:id="echoid-s4364" xml:space="preserve">Mr. </s> <s xml:id="echoid-s4365" xml:space="preserve">le Marêchal de Vauban, <lb/>pour remedier aux inconveniens dont ce ſujet peut être ſuſceptible, <lb/>s’eſt donné la peine d’écrire une ample Inſtruction; </s> <s xml:id="echoid-s4366" xml:space="preserve">&</s> <s xml:id="echoid-s4367" xml:space="preserve">, pour faire <lb/>mieux ſentir la ſolidité des moyens qu’il propoſe, il raporte une <lb/>copie d’un Reglement qui fut fait autreſois en Alſace pour le prix <lb/>que les Entrepreneurs devoient payer aux Soldats employés ſur les <lb/>Travaux; </s> <s xml:id="echoid-s4368" xml:space="preserve">il fait voir les deffauts de ce Reglement, & </s> <s xml:id="echoid-s4369" xml:space="preserve">donne les <lb/>moyens les plus convenables de les corriger. </s> <s xml:id="echoid-s4370" xml:space="preserve">Sans doute qu’il en <lb/>a uſé ainſi pour empêcher que ceux qui auront la conduite des <lb/>Travaux ne tombent dans les mêmes déffauts. </s> <s xml:id="echoid-s4371" xml:space="preserve">Un pareil Ecrit ne <lb/>pouvant être placé plus à propos que dans un Ouvrage comme ce-<lb/>lui-ci, j’ai crû qu’on ſeroit bien aiſe d’en avoir un Extrait.</s> <s xml:id="echoid-s4372" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4373" xml:space="preserve">Les Terres communes & </s> <s xml:id="echoid-s4374" xml:space="preserve">ordinaires ſeront payées à raiſon de <lb/> <anchor type="note" xlink:label="note-0213-01a" xlink:href="note-0213-01"/> douze ſols la toiſe cube dans l’attelier; </s> <s xml:id="echoid-s4375" xml:space="preserve">pour les charger & </s> <s xml:id="echoid-s4376" xml:space="preserve">pour <lb/>les rouler, il ſera augmenté de deux ſols par toiſe, de dix toiſes <lb/>en dix toiſes courantes de chemin dans toute la diſtance de leur <lb/>tranſport, lorſque le terrain ſera uni & </s> <s xml:id="echoid-s4377" xml:space="preserve">plat; </s> <s xml:id="echoid-s4378" xml:space="preserve">& </s> <s xml:id="echoid-s4379" xml:space="preserve">quand il y aura <lb/>à monter ſoit par des rempes de terre où ſur des Ponts, il leur <lb/>ſera payé trois ſols d’augmentation de dix toiſes en dix toiſes cou-<lb/>rantes, par toiſe cube, au lieu de deux ſols dont il eſt parlé cy-<lb/>devant: </s> <s xml:id="echoid-s4380" xml:space="preserve">lorſque les Soldats travailleront dans les Fondations où <lb/>ils ſeront gênés, il leur ſera augmenté deuxſols par toiſes pour la <lb/>charge juſqu’à douze pieds de profondeur, & </s> <s xml:id="echoid-s4381" xml:space="preserve">la même augmen-<lb/>tation leur ſera accordée de ſix pieds en ſix pieds ſur toute la pro-<lb/>fondeur de leur travail, de maniere qu’au-deſſous de douze pieds <pb o="36" file="0214" n="220" rhead="LA SCIENCE DES INGENIEURS,"/> & </s> <s xml:id="echoid-s4382" xml:space="preserve">juſqu’à la profondeur de ſix autres pieds, il leur ſera payé dans <lb/>l’attelier 14 ſ. </s> <s xml:id="echoid-s4383" xml:space="preserve">& </s> <s xml:id="echoid-s4384" xml:space="preserve">à dix-huit pieds de profondeur, 16 au lieu de <lb/>12 ſ. </s> <s xml:id="echoid-s4385" xml:space="preserve">qui eſt le prix des Ouvrages communs, & </s> <s xml:id="echoid-s4386" xml:space="preserve">ainſi d’un apro-<lb/>fondiſſement à l’autre.</s> </p> <p> <s xml:id="echoid-s4387" xml:space="preserve">Et ſi les Soldats ſont obligés de travailler dans l’eau & </s> <s xml:id="echoid-s4388" xml:space="preserve">de ſe <lb/>moüiller les pieds, ſoit dans les Fondations où aux aprofondiſſe-<lb/>mens des Foſſés, outre le prix cy-deſſus, il leur ſera augmenté 5 ſ. <lb/></s> <s xml:id="echoid-s4389" xml:space="preserve">par toiſe dans l’attelier, enſorte qu’au lieu de 16 ſ. </s> <s xml:id="echoid-s4390" xml:space="preserve">qu’il leur a été <lb/>reglé pour la charge lorſqu’ils ſont à 18 pieds de profondeur, il <lb/>leur en ſera payé 21, pendant les mois de Mars, Avril, May, <lb/>Juin, Juillet, Aouſt, Septembre, & </s> <s xml:id="echoid-s4391" xml:space="preserve">Octobre; </s> <s xml:id="echoid-s4392" xml:space="preserve">& </s> <s xml:id="echoid-s4393" xml:space="preserve">à l’égard des au-<lb/>tres mois d’hyver, l’augmentation ſera de 10 ſ. </s> <s xml:id="echoid-s4394" xml:space="preserve">au lieu de 5 dans <lb/>l’attelier, moyennant quoi les Soldats & </s> <s xml:id="echoid-s4395" xml:space="preserve">Ouvriers ſeront obligés <lb/>de faire des rigolles dans leurs atteliers ſeulement pour l’écoule-<lb/>ment des eaux aux mêmes prix & </s> <s xml:id="echoid-s4396" xml:space="preserve">conditions cy-deſſus; </s> <s xml:id="echoid-s4397" xml:space="preserve">& </s> <s xml:id="echoid-s4398" xml:space="preserve">quant <lb/>à la dépenſe des moulins, elle ſe fera auxfrais des Entrepreneurs.</s> </p> <p> <s xml:id="echoid-s4399" xml:space="preserve">Et comme la qualité du Roc eſt incertaine, le prix de l’exca-<lb/>vation en ſera arbitré par l’Ingenieur qui aura ſoin des Fortifica-<lb/>tions de la Place dans laquelle il ſe trouvera du travail de cette <lb/>nature; </s> <s xml:id="echoid-s4400" xml:space="preserve">& </s> <s xml:id="echoid-s4401" xml:space="preserve">à l’égard du tranſport du moîlon qui en proviendra, <lb/>il ſera ſeulement payé aux Soldats pour la charge 10 ſ. </s> <s xml:id="echoid-s4402" xml:space="preserve">attendu <lb/>qu’il ſe trouve tout tiré & </s> <s xml:id="echoid-s4403" xml:space="preserve">que ce travail ſe peut faire ſans donner <lb/>aucun coup de pioche; </s> <s xml:id="echoid-s4404" xml:space="preserve">mais l’éloignement du chemin ſera payé <lb/>ſur le même pied que les terres & </s> <s xml:id="echoid-s4405" xml:space="preserve">les décombres, ſuivant le ré-<lb/>glement qui a été fait pour le tranſport deſdites terres. </s> <s xml:id="echoid-s4406" xml:space="preserve">Fait à Straſ-<lb/>bourg le 2 Juin 1688.</s> </p> <p> <s xml:id="echoid-s4407" xml:space="preserve">Le premier deffaut remarquable de ce Réglement eſt dans le <lb/> <anchor type="note" xlink:label="note-0214-01a" xlink:href="note-0214-01"/> prix de la charge que l’on taxe à 12 ſ. </s> <s xml:id="echoid-s4408" xml:space="preserve">la raiſon eſt que la qualité <lb/>des terres étant toûjours differente entre celles de la ſuperficie, <lb/>& </s> <s xml:id="echoid-s4409" xml:space="preserve">celles qui ſont 4. </s> <s xml:id="echoid-s4410" xml:space="preserve">5. </s> <s xml:id="echoid-s4411" xml:space="preserve">6 ou 7 pieds plus bas; </s> <s xml:id="echoid-s4412" xml:space="preserve">il s’enſuit qu’il eſt <lb/>impoſſible que la régle ſoit bonne, parce qu’en terres molles ou <lb/>de prairie où l’on peut charger de la premiere main, un homme <lb/>pourra ſuffire au chargeage d’une file de relais, ou dans d’autres <lb/>deux, même trois, ne le pourront pas: </s> <s xml:id="echoid-s4413" xml:space="preserve">cependant, le prix de la <lb/>toiſe étant égal à l’un comme à l’autre, il s’enſuit qu’il y a lézion <lb/>de la part du Roy, quand, le terrain étant bon, il n’y a qu’un ou <lb/>deux hommes à charger; </s> <s xml:id="echoid-s4414" xml:space="preserve">& </s> <s xml:id="echoid-s4415" xml:space="preserve">de la part des Soldats, quand, le ter-<lb/>rain étant mauvais, il y en a pluſieurs.</s> </p> <p> <s xml:id="echoid-s4416" xml:space="preserve">Il n’en eſt pas de même, ſi le prix de la charge eſt fixé à 12 ſ. <lb/></s> <s xml:id="echoid-s4417" xml:space="preserve">par toiſe, & </s> <s xml:id="echoid-s4418" xml:space="preserve">qu’un homme de moyenne force puiſſe lever deux <lb/>toiſes cubes de terre en un jour. </s> <s xml:id="echoid-s4419" xml:space="preserve">L’experience nous aprend que <pb o="37" file="0215" n="221" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> cela ſe peut dans tous les terrains marécageux & de prairie où l’on <lb/>peut charger au louchet de la premiere main, ſans avoir beſoin <lb/>de la pioche, cet homme ſeul, dis-je, gagnera 24 ſ.</s> <s xml:id="echoid-s4420" xml:space="preserve">; ſi au lieu d’un <lb/>on eſt obligé d’y en mettre deux, ils n’en gagneront que 12; </s> <s xml:id="echoid-s4421" xml:space="preserve">s’il <lb/>en faut trois, ils n’en gagneront que 8; </s> <s xml:id="echoid-s4422" xml:space="preserve">ſi quatre, que ſix: </s> <s xml:id="echoid-s4423" xml:space="preserve">& </s> <s xml:id="echoid-s4424" xml:space="preserve">ainſi <lb/>à proportion que le nombre des chargeurs augmentera, le prix <lb/>de leurs journées diminuëra.</s> </p> <p> <s xml:id="echoid-s4425" xml:space="preserve">De cette maniere il réſulte, premierement, que quand il n’y a <lb/>eu qu’un ou deux hommes à charger, le Roy eſt lezé, parce que <lb/>les journées ſont trop cheres; </s> <s xml:id="echoid-s4426" xml:space="preserve">quand il y en a trois, le Soldat gagne <lb/>une journée raiſonnable; </s> <s xml:id="echoid-s4427" xml:space="preserve">mais quand il y en a plus, la perte tom-<lb/>be ſur lui; </s> <s xml:id="echoid-s4428" xml:space="preserve">& </s> <s xml:id="echoid-s4429" xml:space="preserve">ſi on ne peut pas dire que les relais les tirent d’affai-<lb/>res; </s> <s xml:id="echoid-s4430" xml:space="preserve">car nous ferons voir que le même deſſaut s’y rencontre.</s> </p> <p> <s xml:id="echoid-s4431" xml:space="preserve">Secondement, que l’augmentation de 2 ſ. </s> <s xml:id="echoid-s4432" xml:space="preserve">par toiſe dans les <lb/>Fondations gênées juſqu’à 12 pieds de profondeur, n’eſt pas toû-<lb/>jours juſte par tous les endroits où cela ſe trouve, ni l’augmenta-<lb/>tion ſi bien apliquée qu’on n’y puiſſe trouver ſujet de lézion, non <lb/>plus que celle qui accorde le même prix depuis 12 pieds de pro-<lb/>fondeur juſqu’à 18, & </s> <s xml:id="echoid-s4433" xml:space="preserve">autres 2 ſ. </s> <s xml:id="echoid-s4434" xml:space="preserve">depuis 18 juſqu’à 24, & </s> <s xml:id="echoid-s4435" xml:space="preserve">ainſi <lb/>de ſuite de 6 pieds en 6 pieds juſqu’à parfaite profondeur en l’une <lb/>& </s> <s xml:id="echoid-s4436" xml:space="preserve">en l’autre; </s> <s xml:id="echoid-s4437" xml:space="preserve">on ne remedie pas avec aſſés de diſtinction au dé-<lb/>faut de la charge qui peut être plus ou moins difficile que ne porte <lb/>l’augmentation de ce prix.</s> </p> <p> <s xml:id="echoid-s4438" xml:space="preserve">Troiſiémement, que l’augmentation du prix pour ceux qui doi-<lb/>vent travailler dans l’eau n’eſt pas moins défectueuſe, attendu <lb/>que ſi elle eſt plus ou moins abondante & </s> <s xml:id="echoid-s4439" xml:space="preserve">inégalle, il eſt impoſſi-<lb/>ble qu’un prix toujoûrs égal leur puiſſe convenir, de maniere <lb/>qu’il n’y ait lézion de part & </s> <s xml:id="echoid-s4440" xml:space="preserve">d’autre: </s> <s xml:id="echoid-s4441" xml:space="preserve">je dis la même choſe de ce <lb/>qui ſuit, ſans que le plus ou moins de profondeur faſſe rien à cet <lb/>égard, parce qu’il ne s’agit pas d’épuiſement, mais ſeulement de <lb/>la charge.</s> </p> <p> <s xml:id="echoid-s4442" xml:space="preserve">Quatriémement, que le Reglement des relais n’eſt pas moins dé-<lb/>fectueux, en ce que plus il y en a, moins l’Ouvrier gagne: </s> <s xml:id="echoid-s4443" xml:space="preserve">par <lb/>exemple, ſi la charge eſt payée à 12 ſ. </s> <s xml:id="echoid-s4444" xml:space="preserve">la toiſe & </s> <s xml:id="echoid-s4445" xml:space="preserve">le relais à deux, <lb/>& </s> <s xml:id="echoid-s4446" xml:space="preserve">qu’il y ait ſeulement la longueur d’un relais à mener, la toiſe <lb/>reviendra à 14 ſ. </s> <s xml:id="echoid-s4447" xml:space="preserve">auquel cas ſi un homme peut charger 2 toiſes & </s> <s xml:id="echoid-s4448" xml:space="preserve"><lb/>un autre les mener, ce ſera deux hommes d’employés pour char-<lb/>ger & </s> <s xml:id="echoid-s4449" xml:space="preserve">mener 2 toiſes de terre, dont le prix reviendra à 28 ſ. </s> <s xml:id="echoid-s4450" xml:space="preserve">les <lb/>deux, partant chaque homme gagnera 14 ſ. </s> <s xml:id="echoid-s4451" xml:space="preserve">qui eſt une journée <lb/>trop forte; </s> <s xml:id="echoid-s4452" xml:space="preserve">mais s’il faut mener les terres à 20 toiſes, il faudra <lb/>établir deux relais, & </s> <s xml:id="echoid-s4453" xml:space="preserve">par conſéquent ajoûter un homme aux deux <pb o="38" file="0216" n="222" rhead="LA SCIENCE DES INGENIEURS,"/> qui feront trois; </s> <s xml:id="echoid-s4454" xml:space="preserve">cependant le prix de la toiſe n’augmentant que <lb/>de 2 ſ. </s> <s xml:id="echoid-s4455" xml:space="preserve">il arrivera que celui de 2 toiſes ne ſera que de 32 ſ. </s> <s xml:id="echoid-s4456" xml:space="preserve">qui <lb/>diviſés à trois hommes feront 10 ſ. </s> <s xml:id="echoid-s4457" xml:space="preserve">8 den. </s> <s xml:id="echoid-s4458" xml:space="preserve">chacun, ainſi dès le ſe-<lb/>cond relais, voilà 3 ſ. </s> <s xml:id="echoid-s4459" xml:space="preserve">4 den. </s> <s xml:id="echoid-s4460" xml:space="preserve">de diminution; </s> <s xml:id="echoid-s4461" xml:space="preserve">ſi la diſtance eſt de <lb/>trois relais ou de 30 toiſes, au lieu de trois hommes il en faudra <lb/>quatre pour mener 2 toiſes de terre, qui à 18 ſ. </s> <s xml:id="echoid-s4462" xml:space="preserve">la toiſe feront <lb/>36 ſ. </s> <s xml:id="echoid-s4463" xml:space="preserve">les deux, & </s> <s xml:id="echoid-s4464" xml:space="preserve">9 ſ. </s> <s xml:id="echoid-s4465" xml:space="preserve">pour la journée de chaque Ouvrier: </s> <s xml:id="echoid-s4466" xml:space="preserve">que ſi <lb/>ledit tranſport eſt de 4 relais, il faudra 5 hommes pour charger <lb/>& </s> <s xml:id="echoid-s4467" xml:space="preserve">mener ces 2 toiſes de terre, qui travaillant toûjours d’égale <lb/>force ne gagneront que 8 ſ. </s> <s xml:id="echoid-s4468" xml:space="preserve">chacun, parce que la toiſe cube ne <lb/>reviendra qu’à 20 ſ. </s> <s xml:id="echoid-s4469" xml:space="preserve">finalement ſi ce même tranſport va juſqu’à <lb/>50 toiſes de diſtance du lieu d’où l’on charge, ou cinq relais, il <lb/>faudra 6 hommes pour charger & </s> <s xml:id="echoid-s4470" xml:space="preserve">mener ces 2 toiſes de terre qui <lb/>reviendront à 44 ſ. </s> <s xml:id="echoid-s4471" xml:space="preserve">leſquels diviſés en ſix feront 7 ſ. </s> <s xml:id="echoid-s4472" xml:space="preserve">4 den. </s> <s xml:id="echoid-s4473" xml:space="preserve">cha-<lb/>cun, qui eſt une journée un peu foible & </s> <s xml:id="echoid-s4474" xml:space="preserve">qui la deviendra toûjours <lb/>de plus en plus à meſure qu’il faudra augmenter les relais; </s> <s xml:id="echoid-s4475" xml:space="preserve">deſorte <lb/>qu’à 10 relais les journées ne reviendront qu’à 5 ſ. </s> <s xml:id="echoid-s4476" xml:space="preserve">9 den. </s> <s xml:id="echoid-s4477" xml:space="preserve">ce qui <lb/>n’eſt pas ſuportable: </s> <s xml:id="echoid-s4478" xml:space="preserve">ainſi, quoiqu’il y ait égalité de travail, les jour-<lb/>nées diminuent à meſure que le tranſport s’éloigne.</s> </p> <p> <s xml:id="echoid-s4479" xml:space="preserve">Si l’on vouloit augmenter chaque relais de 6 den. </s> <s xml:id="echoid-s4480" xml:space="preserve">d’un ſol, ou <lb/>même davantage, on ne parviendroit pas encore à mettre ce Ré-<lb/>glement dans l’égalité neceſſaire à un travail bien ordonné, le Roy <lb/>étant toûjours lézé aux deux premiers relais, & </s> <s xml:id="echoid-s4481" xml:space="preserve">le Soldat dans la <lb/>plus grande partie des autres, & </s> <s xml:id="echoid-s4482" xml:space="preserve">beaucoup d’inégalité dans les jour-<lb/>nées, ce qui n’eſt pas raiſonnable, attendu que les Ouvriers qui <lb/>travaillent également & </s> <s xml:id="echoid-s4483" xml:space="preserve">d’égale force dans un même ouvrage doi-<lb/>vent autant gagner les uns que les autres; </s> <s xml:id="echoid-s4484" xml:space="preserve">à quoi il faut ajouter <lb/>que dans tous les lieux où la quantité de relais ſurpaſſe le nombre <lb/>de 10, la lézion y eſt bien plus ſenſible, parce qu’à meſure que le <lb/>nombre de relais augmente, le prix des journées diminue: </s> <s xml:id="echoid-s4485" xml:space="preserve">voilà <lb/>donc les deffauts de ce Reglement prouvés de maniere à n’en pou-<lb/>voir douter; </s> <s xml:id="echoid-s4486" xml:space="preserve">je ne dis rien des autres particularités, parce que ce <lb/>ne ſont que des conſequences de ces deux principes, qui étant <lb/>d’eux-mêmes déſectueux, il s’enſuit que tout ce qui en dépend ne <lb/>peut manquer de l’être.</s> </p> <p> <s xml:id="echoid-s4487" xml:space="preserve">Comme ces deffauts ne proviennent que de ce que le prix du <lb/> <anchor type="note" xlink:label="note-0216-01a" xlink:href="note-0216-01"/> chargeage eſt trop fort, & </s> <s xml:id="echoid-s4488" xml:space="preserve">celui des relais trop foible, & </s> <s xml:id="echoid-s4489" xml:space="preserve">de ce <lb/>que ni l’un ni l’autre n’ont pas été reglés ſur le prix commun <lb/>des journées que l’on veut faire gagner aux Soldats, il ſera fort <lb/>aiſé de le corriger en leur donnant un prix modique, non en vuë <lb/>de les faire travailler ſur ce pied-là, mais d’en faire l’aplication <pb o="39" file="0217" n="223" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> au prix de la toiſe cube, laiſſant aux Ouvriers après d’en attraper <lb/>ce qu’ils pourront par la force de leurs bras.</s> </p> <p> <s xml:id="echoid-s4490" xml:space="preserve">Il eſt très poſſible de remedier aux inconveniens & </s> <s xml:id="echoid-s4491" xml:space="preserve">d’ôter tout <lb/>pretexte aux Soldats de crier, ſi, au lieu de regler la charge & </s> <s xml:id="echoid-s4492" xml:space="preserve">les <lb/>relais au haſard, & </s> <s xml:id="echoid-s4493" xml:space="preserve">ſans connoiſſance préciſe du prix des terres <lb/>par raport aux differences de leur moleſſe, dureté, & </s> <s xml:id="echoid-s4494" xml:space="preserve">tranſport, le <lb/>Roy a pour agréable d’ordonner ce qu’il lui plaira que le Soldat <lb/>gagne par jour: </s> <s xml:id="echoid-s4495" xml:space="preserve">car ſi par exemple ſa journée eſt reglée à 8 ſ. </s> <s xml:id="echoid-s4496" xml:space="preserve">par <lb/>jour, qui eſt un prix bas & </s> <s xml:id="echoid-s4497" xml:space="preserve">modique pour des gens, qui, travaillant <lb/>à la tâche, vont ordinairement de toute leur force, mais qui ne <lb/>l’eſt pas tant pour des gens, qui, tirant la ſolde du Roy par d’autres <lb/>ſervices, ne ſont cependant employés qu’à celui-ci, du moins <lb/>un certain tems, il n’y a, dis-je, qu’a taxer le chargeage & </s> <s xml:id="echoid-s4498" xml:space="preserve">les re-<lb/>lais par raport aux journées des hommes; </s> <s xml:id="echoid-s4499" xml:space="preserve">& </s> <s xml:id="echoid-s4500" xml:space="preserve">il arrivera que ſi un <lb/>homme charge 2 toiſes de la premiere main & </s> <s xml:id="echoid-s4501" xml:space="preserve">ſans pioche, la <lb/>journée de cet homme montant à<unsure/> 8 ſ. </s> <s xml:id="echoid-s4502" xml:space="preserve">partagée en deux, donnera <lb/>4 ſ. </s> <s xml:id="echoid-s4503" xml:space="preserve">pour la charge de chaque toiſe cube de terre; </s> <s xml:id="echoid-s4504" xml:space="preserve">mais s’il y faut <lb/>deux hommes, leurs deux journées montant à 16 ſ. </s> <s xml:id="echoid-s4505" xml:space="preserve">donneront <lb/>8 ſ. </s> <s xml:id="echoid-s4506" xml:space="preserve">pour chacun, ſi trois hommes, 24 ſ. </s> <s xml:id="echoid-s4507" xml:space="preserve">ſi partagés de rechef en <lb/>deux donneront 12 ſ. </s> <s xml:id="echoid-s4508" xml:space="preserve">pour chaque toiſe cube & </s> <s xml:id="echoid-s4509" xml:space="preserve">ainſi des autres, <lb/>augmentant toûjours de 4 ſ. </s> <s xml:id="echoid-s4510" xml:space="preserve">à chaque fois que l’on ſera obligé <lb/>d’augmenter d’un chargeur.</s> </p> <p> <s xml:id="echoid-s4511" xml:space="preserve">A l’égard des relais, il n’y a pas de meilleur moyen de les régler, <lb/>qu’en les établiſſant à 15 toiſes de diſtance les uns des autres en plain <lb/>terrain, & </s> <s xml:id="echoid-s4512" xml:space="preserve">à 10 en montant, & </s> <s xml:id="echoid-s4513" xml:space="preserve">du ſurplus fixer le prix de chacun <lb/>à 4 ſ. </s> <s xml:id="echoid-s4514" xml:space="preserve">par toiſe, qui produit toûjours cette journée d’hommes qui <lb/>doit ſervir de baſe au reglement du prix, mais non au gain des <lb/>Soldats; </s> <s xml:id="echoid-s4515" xml:space="preserve">car tel gagnera juſqu’à 10 & </s> <s xml:id="echoid-s4516" xml:space="preserve">11 ſ. </s> <s xml:id="echoid-s4517" xml:space="preserve">que d’autres n’en ga-<lb/>gneront pas plus de 6 ou 7, ſelon leur force & </s> <s xml:id="echoid-s4518" xml:space="preserve">le mouvement <lb/>qu’ils ſe donneront, ce qui ne peut que bien réüſſir & </s> <s xml:id="echoid-s4519" xml:space="preserve">avec beau-<lb/>coup de juſtice; </s> <s xml:id="echoid-s4520" xml:space="preserve">car, chacun gagnera ſuivant ſon travail, & </s> <s xml:id="echoid-s4521" xml:space="preserve">au-<lb/>cun d’eux n’aura lieu de ſe plaindre que de lui-même.</s> </p> <p> <s xml:id="echoid-s4522" xml:space="preserve">A ce que deſſus on doit ajoûter, premierement, de fixer la <lb/>diſtance des relais à 15 toiſes en plain Pays, & </s> <s xml:id="echoid-s4523" xml:space="preserve">à 10, où il faut <lb/>monter par des Ponts ou par des rempes, comme il a déja été dit <lb/>ſans changer de prix; </s> <s xml:id="echoid-s4524" xml:space="preserve">la raiſon eſt que d’experience faite & </s> <s xml:id="echoid-s4525" xml:space="preserve">plu-<lb/>ſieurs fois réïterée, une toiſe cube de terre peut-être menée en <lb/>250 broüettées, & </s> <s xml:id="echoid-s4526" xml:space="preserve">deux en 500, qui eſt la tâche commune <lb/>que nous aſſignons à un ouvrier de moyenne force, & </s> <s xml:id="echoid-s4527" xml:space="preserve">pour les <lb/>mener en place, il faudra qu’il faſſe 15000 toiſes de chemin en <lb/>plaine, dont la moitié charge, & </s> <s xml:id="echoid-s4528" xml:space="preserve">10000 en montant & </s> <s xml:id="echoid-s4529" xml:space="preserve">d’étenduë, <pb o="40" file="0218" n="224" rhead="LA SCIENCE DES INGENIEURS,"/> c’eſt-à-dire ſix lieuës de 2500 toiſes chacune en plaine, & </s> <s xml:id="echoid-s4530" xml:space="preserve">près <lb/>de quatre en montant & </s> <s xml:id="echoid-s4531" xml:space="preserve">d’étenduë, or il n’y a point d’ouvrier qui <lb/>n’aime autant faire 15 toiſes en plaine que 10 en montant.</s> </p> <p> <s xml:id="echoid-s4532" xml:space="preserve">Secondement, fixer le tems du travail à 10 heures par jour, & </s> <s xml:id="echoid-s4533" xml:space="preserve">ce-<lb/>lui du repos à trois, qui font en tout 13 heures de ſujetion, com-<lb/>mençant le travail à 5 heures du matin pour être à 5 & </s> <s xml:id="echoid-s4534" xml:space="preserve">demie en <lb/>train, le quitter à 8 heures pour déjeuner une demie heure; </s> <s xml:id="echoid-s4535" xml:space="preserve">le <lb/>reprendre à 8 & </s> <s xml:id="echoid-s4536" xml:space="preserve">demie, pour le quitter de rechef à 11 & </s> <s xml:id="echoid-s4537" xml:space="preserve">aller dî-<lb/>ner; </s> <s xml:id="echoid-s4538" xml:space="preserve">plus le reprendre à une heure, pour le quitter à 3 & </s> <s xml:id="echoid-s4539" xml:space="preserve">demie; <lb/></s> <s xml:id="echoid-s4540" xml:space="preserve">enfin le reprendre à 4 pour le quitter tout-à-fait à 7.</s> </p> <p> <s xml:id="echoid-s4541" xml:space="preserve">J’eſtime qu’on peut encore régler le travail comme cy-après.</s> </p> <p> <s xml:id="echoid-s4542" xml:space="preserve">Le commencer par exemple à 5 heures du matin & </s> <s xml:id="echoid-s4543" xml:space="preserve">travailler <lb/>juſqu’à 8, le quitter depuis 8 juſqu’à 9, & </s> <s xml:id="echoid-s4544" xml:space="preserve">le reprendre depuis <lb/>9 juſqu’à 12, le diſcontinuer juſqu’à 2, & </s> <s xml:id="echoid-s4545" xml:space="preserve">le reprendre enſuite, <lb/>& </s> <s xml:id="echoid-s4546" xml:space="preserve">le continuer juſqu’à 7 du ſoir, ce qui fait 10 heures de travail, <lb/>& </s> <s xml:id="echoid-s4547" xml:space="preserve">trois heures de repos par jour.</s> </p> <p> <s xml:id="echoid-s4548" xml:space="preserve">On pourra ſoûtenir le travail ſur ce pied 8 mois de l’année, <lb/>ſavoir Mars, Avril, May, Juin, Juillet, Aouſt, Septembre, & </s> <s xml:id="echoid-s4549" xml:space="preserve"><lb/>Octobre; </s> <s xml:id="echoid-s4550" xml:space="preserve">pour les 4 autres mois qui ſont d’hyver, on en pourra <lb/>retrancher les déjeunés & </s> <s xml:id="echoid-s4551" xml:space="preserve">les goutés, & </s> <s xml:id="echoid-s4552" xml:space="preserve">réduire le tems du tra-<lb/>vail à 7 heures, pendant leſquelles je ſuis perſuadé que les ouvriers <lb/>ne feront guére plus de demie journée d’Eté, à cauſe du froid & </s> <s xml:id="echoid-s4553" xml:space="preserve"><lb/>du mauvais tems; </s> <s xml:id="echoid-s4554" xml:space="preserve">je tiens qu’il ne faut point impoſer davantage <lb/>au Soldat qui a ſa tâche, parce qu’il eſt certain que 10 heures de <lb/>travail d’un homme qui a pour chaſſavant ſon intereſt en valent <lb/>du moins 15 d’autre qui a ſa journée reglée; </s> <s xml:id="echoid-s4555" xml:space="preserve">de les pouſſer plus <lb/>loin, c’eſt les outrer & </s> <s xml:id="echoid-s4556" xml:space="preserve">les expoſer à devenir malades, & </s> <s xml:id="echoid-s4557" xml:space="preserve">ne pou-<lb/>voir pas tenir longtems.</s> </p> <p> <s xml:id="echoid-s4558" xml:space="preserve">Troiſiémement, d’augmenter un homme aux chargeurs quand <lb/>il y aura de l’eau dans le travail, & </s> <s xml:id="echoid-s4559" xml:space="preserve">qu’on ſera obligé à des épui-<lb/>ſemens; </s> <s xml:id="echoid-s4560" xml:space="preserve">ſi c’eſt en Eté, en conſidération des rigoles qu’il faut pour <lb/>les écouler vers les moulins qui l’épuiſent, & </s> <s xml:id="echoid-s4561" xml:space="preserve">du nettoyement des <lb/>rampes & </s> <s xml:id="echoid-s4562" xml:space="preserve">de la terre qui ſe perd par les chemins, & </s> <s xml:id="echoid-s4563" xml:space="preserve">ſi elles ſont <lb/>ſi abondantes qu’un homme ſeul n’y puiſſe pas fournir, augmenter <lb/>d’un & </s> <s xml:id="echoid-s4564" xml:space="preserve">demi ou de deux, ainſi du reſte ſuivant les difficultés qui <lb/>ſe preſenteront; </s> <s xml:id="echoid-s4565" xml:space="preserve">ſi c’eſt en Hyver, & </s> <s xml:id="echoid-s4566" xml:space="preserve">que le Soldat ait le pied moüil-<lb/>lé, on pourra en conſidération du froid qu’il aura à ſouffrir lui aug-<lb/>menter encore d’un homme de plus, ce qui doit être arbitré par <lb/>l’Ingenieur en chef avec beaucoup de circonſpection.</s> </p> <p> <s xml:id="echoid-s4567" xml:space="preserve">Quatriémement, d’augmenter d’un homme à la charge où les <lb/>terres ſeront dures, ou de deux, même de trois, ſelon que l’ou- <pb o="41" file="0219" n="225" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> vrage ſera difficile, de cette façon on pourra même régler l’ex-<lb/>cavation du roc & </s> <s xml:id="echoid-s4568" xml:space="preserve">rocailles aſſés juſte, puiſque le plus ou moins <lb/>d’hommes au chargeage & </s> <s xml:id="echoid-s4569" xml:space="preserve">piochage en fera toute la difference, <lb/>& </s> <s xml:id="echoid-s4570" xml:space="preserve">c’eſt ſurquoi les Soldats ſe réglent aſſés bien d’eux-mêmes.</s> </p> <p> <s xml:id="echoid-s4571" xml:space="preserve">Cinquiémement, chomer tous les Dimanches, mais non les <lb/>Fêtes, comme étant très-certain qu’on ne gagne rien au travail <lb/>des Dimanches, par la raiſon que tout homme qui a travaillé ſix <lb/>jours tout de ſuite a beſoin de repos le ſeptiéme.</s> </p> <p> <s xml:id="echoid-s4572" xml:space="preserve">Sixiémement, regler un peu la diſtance moyenne des relais du <lb/>centre de l’ouvrage au centre du tranſport, pour éviter les con-<lb/>teſtations qui pourroient arriver à cet égard; </s> <s xml:id="echoid-s4573" xml:space="preserve">&</s> <s xml:id="echoid-s4574" xml:space="preserve">, parce que d’or-<lb/>dinaire les Soldats allongent & </s> <s xml:id="echoid-s4575" xml:space="preserve">racourciſſent leur relais comme il <lb/>leur plaît, compter toûjours la diſtance totale du lieu où l’on <lb/>charge, à celui où l’on décharge, & </s> <s xml:id="echoid-s4576" xml:space="preserve">régler après les relais com-<lb/>me ci-devant, donnant le plus, & </s> <s xml:id="echoid-s4577" xml:space="preserve">ôtant le moins, quand il défau-<lb/>dra ou ſurpaſſera le demi relais, pour éviter tout ce qui peut faire <lb/>embarras.</s> </p> <p> <s xml:id="echoid-s4578" xml:space="preserve">Septiémement, obſerver dans une même file de relais, quand il <lb/>s’en trouvera où il y aura à monter ou deſcendre, de régler ceux <lb/>des montées à 10 toiſes, comme il a été dit cy-devant, & </s> <s xml:id="echoid-s4579" xml:space="preserve">ceux <lb/>de la plaine à 15, ſans rien changer au prix des uns & </s> <s xml:id="echoid-s4580" xml:space="preserve">des au-<lb/>tres.</s> </p> <p> <s xml:id="echoid-s4581" xml:space="preserve">Huitiémement, ne rien changer non plus où il s’agira de tra-<lb/>vailler dans le Roc, puiſque le nombre de Chargeurs ou Rocteurs <lb/>qu’il y faudra de plus, & </s> <s xml:id="echoid-s4582" xml:space="preserve">le moins de gens au relais, ſuffira pour <lb/>en regler le prix au juſte, en y prenant garde de près. </s> <s xml:id="echoid-s4583" xml:space="preserve">On pourra <lb/>d’ailleurs ajoûter quelque choſe pour l’entoiſage du moîlon qui <lb/>ſera propre à bâtir.</s> </p> <p> <s xml:id="echoid-s4584" xml:space="preserve">Du ſurplus, l’obligation des Entrepreneurs envers les Ouvriers <lb/>doit être de leur fournir les outils propres au travail, de faire tous <lb/>les épuiſemens d’eau à leur dépens, les Ponts où il en faudra <lb/>fournir les planches, arranger ou faire battre les terres où il ſera <lb/>neceſſaire, couper des rampes dans les taluds qui leur ſeront reglés, <lb/>à quoi les mêmes ſeront obligés: </s> <s xml:id="echoid-s4585" xml:space="preserve">en conſideration de cette obli-<lb/>gation des Entrepreneurs, qui ſont de plus ſujets à d’autres vers <lb/>le Roy, comme de faire l’ouvrage bon & </s> <s xml:id="echoid-s4586" xml:space="preserve">ſolide dans un certain <lb/>tems, & </s> <s xml:id="echoid-s4587" xml:space="preserve">d’en répondre ſuivant les conventions de leur marché, <lb/>on donnera 6 ſ. </s> <s xml:id="echoid-s4588" xml:space="preserve">de plus qu’aux Soldats pour le prix de la toiſe, <lb/>en conſideration de tous les devoirs à quoi ils ſont tenus; </s> <s xml:id="echoid-s4589" xml:space="preserve">avec <lb/>cette remarque, que plus il y a de relais, plus leur charges ſont <lb/>grandes, à cauſe de la quantité de brouettes & </s> <s xml:id="echoid-s4590" xml:space="preserve">d’outils qu’ils <pb o="42" file="0220" n="226" rhead="LA SCIENCE DES INGENIEURS,"/> doivent fournir, ſurquoi il eſt encore à obſerver, que pendant les <lb/>Hyvers les frais augmentent de beaucoup, à cauſe de la briéveté <lb/>des jours, difficulté des Voitures, abondance des eaux, bouës & </s> <s xml:id="echoid-s4591" xml:space="preserve"><lb/>gelées; </s> <s xml:id="echoid-s4592" xml:space="preserve">c’eſt pourquoi les 6 ſ. </s> <s xml:id="echoid-s4593" xml:space="preserve">n’y pourront pas toûjours ſuffire, à <lb/>moins qu’on n’ait ſoin de leur ménager du travail aiſé, commode, <lb/>& </s> <s xml:id="echoid-s4594" xml:space="preserve">en petite quantité, le mieux eſt de ne les obliger que le moins <lb/>qu’on pourra à de grands travaux de terre dans ces tems-là, car <lb/>s’ils ont quelqu’avantage pendant l’Eté, il eſt certain que les grands <lb/>ouvrages d’Hyver les conſommeront: </s> <s xml:id="echoid-s4595" xml:space="preserve">cependant c’eſt une choſe <lb/>à bien examiner, car les ouvrages d’Eté où il y a peu de relais <lb/>& </s> <s xml:id="echoid-s4596" xml:space="preserve">de conſommation, il y a auſſi bien moins de frais, & </s> <s xml:id="echoid-s4597" xml:space="preserve">par con-<lb/>ſequent beaucoup plus d’avantages qui ſe peuvent moderer ſelon <lb/>les lieux & </s> <s xml:id="echoid-s4598" xml:space="preserve">la facilité des ouvrages.</s> </p> <p> <s xml:id="echoid-s4599" xml:space="preserve">De cet ordre une fois établi réſultera pluſieurs connoiſſances <lb/>aux gens qui font travailler.</s> </p> <p> <s xml:id="echoid-s4600" xml:space="preserve">Premierement, que le prix de la toiſe augmentant à chaque <lb/>relais de 4. </s> <s xml:id="echoid-s4601" xml:space="preserve">ſ. </s> <s xml:id="echoid-s4602" xml:space="preserve">il s’enſuivra que dès auſſi-tôt qu’on aura donné prix <lb/>à ce chargeage, il n’y aura qu’à compter le nombre de relais & </s> <s xml:id="echoid-s4603" xml:space="preserve"><lb/>les frais de l’Entrepreneur, pour ſavoir au juſte le prix qu’on doit <lb/>donner à la toiſe.</s> </p> <p> <s xml:id="echoid-s4604" xml:space="preserve">Secondement, qu’on aura toûjours une connoiſſance parfaite <lb/>du prix de la toiſe de terre, puiſque ce prix hauſſera & </s> <s xml:id="echoid-s4605" xml:space="preserve">baiſſera <lb/>ſelon le nombre de chargeurs & </s> <s xml:id="echoid-s4606" xml:space="preserve">de relais.</s> </p> <p> <s xml:id="echoid-s4607" xml:space="preserve">Troiſiémement, que quelque nombre d’ouvriers qu’il y ait, le <lb/>Roy ne payera jamais que 8 ſ. </s> <s xml:id="echoid-s4608" xml:space="preserve">pour la journée d’un chacun, qui <lb/>n’étant pas cependant diſtribué ſur le pied de journée, mais bien <lb/>ſur le pied de ce qu’ils pourront faire d’ouvrage, il s’enſuivra que <lb/>S. </s> <s xml:id="echoid-s4609" xml:space="preserve">M. </s> <s xml:id="echoid-s4610" xml:space="preserve">ſera ſervie très-diligemment, à bon marché, ſans peine, & </s> <s xml:id="echoid-s4611" xml:space="preserve"><lb/>ſans violenter perſonne.</s> </p> <p> <s xml:id="echoid-s4612" xml:space="preserve">Quatriémement, que ſi on fait attention à l’utilité de cette <lb/>propoſition, on la trouvera très-avantageuſe, d’autant que la jour-<lb/>née du Roy étant aujourd’hui reglée à 10 ſ. </s> <s xml:id="echoid-s4613" xml:space="preserve">il n’y a pas d’hommes <lb/>de ceux qui travaillent à la tâche qui n’en mérite mieux 15, que <lb/>ceux qui ſont à la journée de 10; </s> <s xml:id="echoid-s4614" xml:space="preserve">cependant, on n’en demande ici <lb/>que 8 pour faire aller les Soldats de toute leur force.</s> </p> <p> <s xml:id="echoid-s4615" xml:space="preserve">Cinquiémement, que pour avoir plus près à mener, le Soldat <lb/>n’en gagne pas davantage, ni moins pour avoir plus loin, la toiſe <lb/>revenant toûjours au prix proportionné à la quantité de ſes re-<lb/>lais & </s> <s xml:id="echoid-s4616" xml:space="preserve">à la difficulté de la charge.</s> </p> <p> <s xml:id="echoid-s4617" xml:space="preserve">Sixiémement, que quoiqu’on ſupoſe 6 ſ. </s> <s xml:id="echoid-s4618" xml:space="preserve">par toiſe à l’Entrepre-<lb/>neur pour ſes peines, fournitures de planches, ponts, brouëttes, <pb o="43" file="0221" n="227" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> outils, épuiſemens d’eaux, façon de montées, &</s> <s xml:id="echoid-s4619" xml:space="preserve">c. </s> <s xml:id="echoid-s4620" xml:space="preserve">cela ne ſe <lb/>doit entendre que des endroits où il y a grande conſommation <lb/>d’outils, comme ceux où il y a pluſieurs relais, & </s> <s xml:id="echoid-s4621" xml:space="preserve">où l’on eſt obligé <lb/>de travailler pendant l’Hyver dans le tems des grandes gelées, où <lb/>pendant que les terres ſont trempées & </s> <s xml:id="echoid-s4622" xml:space="preserve">boüeuſes, & </s> <s xml:id="echoid-s4623" xml:space="preserve">en un mot où <lb/>il y a beaucoup de peine & </s> <s xml:id="echoid-s4624" xml:space="preserve">peu d’ouvrage, autrement on peut <lb/>leur donner depuis 3, juſqu’à 4 & </s> <s xml:id="echoid-s4625" xml:space="preserve">5 ſ. </s> <s xml:id="echoid-s4626" xml:space="preserve">ſelon que les frais des épui-<lb/>ſemens & </s> <s xml:id="echoid-s4627" xml:space="preserve">les conſommations en ſont plus ou moins conſidéra-<lb/>bles.</s> </p> <p> <s xml:id="echoid-s4628" xml:space="preserve">Il eſt à remarquer que le prix des journées à 8 ſ.</s> <s xml:id="echoid-s4629" xml:space="preserve">, qui étoit paſſa-<lb/>ble pour des Soldats dans le tems que ce Mémoire a été fait, ne <lb/>ſuffiroit pas preſentement que le rehauſſement des monnoyes & </s> <s xml:id="echoid-s4630" xml:space="preserve">les <lb/>mauvaiſes années ont tout rencheri; </s> <s xml:id="echoid-s4631" xml:space="preserve">d’ailleurs cela dépend auſſi <lb/>du Pays où l’on fait travailler par raport aux aiſances ou aux difficul-<lb/>tés que les Troupes trouvent à vivre à juſte prix: </s> <s xml:id="echoid-s4632" xml:space="preserve">c’eſt à l’Ingenieur <lb/>en chef, ou au Directeur, à avoir toutes ces conſidérations pour <lb/>que le Roy n’y ſoit pas lezé, & </s> <s xml:id="echoid-s4633" xml:space="preserve">que les Soldats auſſi-bien que les <lb/>Entrepreneurs ſe tirent judicieuſement d’affaire; </s> <s xml:id="echoid-s4634" xml:space="preserve">ainſi, ſans s’arrêter <lb/>conſtamment à cet article, on tirera toûjours beaucoup de con-<lb/>noiſſance de ce Mémoire, qui eſt regardé de tousles anciens Inge-<lb/>nieurs comme la meilleure Inſtruction qui ait été écrite ſur ce ſujet.</s> <s xml:id="echoid-s4635" xml:space="preserve"/> </p> <div xml:id="echoid-div264" type="float" level="3" n="1"> <note position="right" xlink:label="note-0213-01" xlink:href="note-0213-01a" xml:space="preserve">Copie du <lb/>Reglement <lb/>fait en Al-<lb/>face pour <lb/>le prix que <lb/>les Entre-<lb/>preneurs <lb/>doivent <lb/>payeraux <lb/>ſoldats em-<lb/>ployés au <lb/>tranſport <lb/>& remuë-<lb/>ment des <lb/>Terres de <lb/>la Fortifi-<lb/>cation des <lb/>Places de <lb/>Sa Majeſté.</note> <note position="left" xlink:label="note-0214-01" xlink:href="note-0214-01a" xml:space="preserve">Deffauts <lb/>de ce Re-<lb/>glement: <lb/>c’eſt Mr. de <lb/>Vauban <lb/>qui parle.</note> <note position="left" xlink:label="note-0216-01" xlink:href="note-0216-01a" xml:space="preserve">Des mo-<lb/>ïens les <lb/>plus con-<lb/>venables <lb/>pour corri-<lb/>ger ces <lb/>deffauts.</note> </div> <p> <s xml:id="echoid-s4636" xml:space="preserve">Dans de certains Pays, on diſtingue ordinairement pour le marché <lb/>des Ouvrages trois ſortes de terres pour en régler le prix, la terre <lb/>douce ou épierrée pour les parapets, la roccaille, & </s> <s xml:id="echoid-s4637" xml:space="preserve">le roc.</s> <s xml:id="echoid-s4638" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4639" xml:space="preserve">Toute terre, où l’on n’a beſoin que du louchet pour l’enlever, <lb/>eſt regardée comme terre ordinaire: </s> <s xml:id="echoid-s4640" xml:space="preserve">la pierre morte, qui ſe trouve <lb/>mêlée d’un peu de terre, & </s> <s xml:id="echoid-s4641" xml:space="preserve">où il ne faut ni maſſe, ni pince, & </s> <s xml:id="echoid-s4642" xml:space="preserve">où <lb/>il ſuffit de la pioche & </s> <s xml:id="echoid-s4643" xml:space="preserve">du pic, eſt reputée rocaille. </s> <s xml:id="echoid-s4644" xml:space="preserve">Toute pierre vive, <lb/>où il faut ſe ſervir de pic, de coin, de maſſe, d’aiguille, eſt apellée <lb/>roc.</s> <s xml:id="echoid-s4645" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4646" xml:space="preserve">Dans le Pays-Bas, où l’on ne rencontre guére de roc ni de rocaille, <lb/>on diſtingue dans les marchés deux ſortes de terre; </s> <s xml:id="echoid-s4647" xml:space="preserve">l’une eſt apellée <lb/>terre hors d’eau, qui eſt celle qu’on peut travailler à ſec; </s> <s xml:id="echoid-s4648" xml:space="preserve">& </s> <s xml:id="echoid-s4649" xml:space="preserve">l’autre <lb/>terre dans l’eau, qui ne peut s’enlever ſans beaucoup d’incommo-<lb/>dité: </s> <s xml:id="echoid-s4650" xml:space="preserve">toutes ces terres differentes pourront s’eſtimer en ſuivant <lb/>l’Inſtruction de Mr. </s> <s xml:id="echoid-s4651" xml:space="preserve">de Vauban; </s> <s xml:id="echoid-s4652" xml:space="preserve">c’eſt-à-dire, en s’attachant à la quan-<lb/>tité d’hommes qu’il faut pour en tranſporter une toiſe cube, & </s> <s xml:id="echoid-s4653" xml:space="preserve">aux <lb/>journées qu’ils doivent gagner.</s> <s xml:id="echoid-s4654" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4655" xml:space="preserve">Dans une terre ordinaire, un attelier de quatre Soldats, com-<lb/>poſé d’un piocheur, d’un chargeur, & </s> <s xml:id="echoid-s4656" xml:space="preserve">de deux autres qui brouët-<lb/>tent, peut tranſporter à 10 toiſes de l’attelier, deux toiſes & </s> <s xml:id="echoid-s4657" xml:space="preserve">un tiers <pb o="44" file="0222" n="228" rhead="LA SCIENCE DES INGENIEURS,"/> cubes dans un jour d’Eté, & </s> <s xml:id="echoid-s4658" xml:space="preserve">un peu plus de la moitié dans un jour <lb/>d’Hyver.</s> <s xml:id="echoid-s4659" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4660" xml:space="preserve">La rocaille étant comme je l’ay déja dit une pierre morte, mê-<lb/>lée de terre, la difficulté de ſa foüille eſt beaucoup plus grande, <lb/>que celle des terres ordinaires, c’eſt pourquoi le prix en eſt auſſi <lb/>plus conſiderable: </s> <s xml:id="echoid-s4661" xml:space="preserve">c’eſt à la prudence de l’Ingenieur de l’aug-<lb/>menter, enſorte que les Soldats y trouvent leur compte; </s> <s xml:id="echoid-s4662" xml:space="preserve">&</s> <s xml:id="echoid-s4663" xml:space="preserve">, quoi <lb/>qu’il ſoit difficile de déterminer à quoi peut aller cette augmenta-<lb/>tion, je dirai pourtant que la toiſe cube de Rocaille vaut à peu <lb/>près le double des terres ordinaires.</s> <s xml:id="echoid-s4664" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4665" xml:space="preserve">Quant au roc, il faut auſſi avoir égard à ſa qualité & </s> <s xml:id="echoid-s4666" xml:space="preserve">à ſa dure-<lb/>té: </s> <s xml:id="echoid-s4667" xml:space="preserve">on le tire par mine, dont l’apareil eſt de quatre hommes, qui <lb/>s’aprofondiſſent de cinq pieds dans un roc ordinaire; </s> <s xml:id="echoid-s4668" xml:space="preserve">mais comme <lb/>le marbre eſt d’une nature plus dure, ils ne peuvent guere s’y apro-<lb/>fondir que de quatre pieds, qui produiſent tout au plus une demi <lb/>toiſe cube, qui conſume environ deux livres de poudre pour char-<lb/>ger les petards: </s> <s xml:id="echoid-s4669" xml:space="preserve">outre ces quatre hommes, on ajoûte encore deux <lb/>manœuvres pour arracher les pierres ébranlées par la mine, & </s> <s xml:id="echoid-s4670" xml:space="preserve">ôter <lb/>les decombres: </s> <s xml:id="echoid-s4671" xml:space="preserve">ainſi ſachant ce que les uns & </s> <s xml:id="echoid-s4672" xml:space="preserve">les autres doivent <lb/>gagner par jour, & </s> <s xml:id="echoid-s4673" xml:space="preserve">ce qu’il en coûtera pour les outils & </s> <s xml:id="echoid-s4674" xml:space="preserve">la poudre, <lb/>on pourra ſavoir à combien reviendra la toiſe cube.</s> <s xml:id="echoid-s4675" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4676" xml:space="preserve">Pour aprofondir dans le roc, on ſe ſert d’une aiguille, ou bar-<lb/>re de fer, de bonne trempe bien acerée, pointuë par un de ſes <lb/>bouts, ayant ſix ou ſept pieds de longueur, deux hommes la met-<lb/>tent en mouvement pour faire un trou, en maniere de petit <lb/>puits, capable de contenir une certaine quantité de poudre, <lb/>après avoir chargé cette petite mine, on bouche le trou avec <lb/>un tampon chaſſé à force, afin que la poudre faſſe un plus <lb/>grand effet, on y met le feu par le moyen d’un morceau d’ama-<lb/>douë, qui, ne ſe communiquant à la poudre qu’au bout d’un cer-<lb/>tain tems, laiſſe aux ouvriers la liberté de ſe retirer; </s> <s xml:id="echoid-s4677" xml:space="preserve">la mine ayant <lb/>écarté & </s> <s xml:id="echoid-s4678" xml:space="preserve">ébranlé les pierres, on en fait le deblais, & </s> <s xml:id="echoid-s4679" xml:space="preserve">on repete la <lb/>même manœuvre autant de fois qu’on le juge neceſſaire.</s> <s xml:id="echoid-s4680" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4681" xml:space="preserve">Avant de commencer la foüille des terres, il eſt de la derniere <lb/>conſequence d’en bien indiquer le tranſport, & </s> <s xml:id="echoid-s4682" xml:space="preserve">ſavoir la quantité <lb/>qu’il en faudra pour la conſtruction du projet que l’on veut execu-<lb/>ter; </s> <s xml:id="echoid-s4683" xml:space="preserve">ceux qui font ces projets doivent en donner des memoires, <lb/>afin que les profils étant bien expliqués, on ne s’aprofondiſſe qu’à <lb/>proportion des remblais qu’on aura à faire: </s> <s xml:id="echoid-s4684" xml:space="preserve">c’eſt ordinairement la <lb/>nature du terrain qui détermine le parti que l’on doit prendre; </s> <s xml:id="echoid-s4685" xml:space="preserve">car <lb/>ſi l’on peut creuſer à ſec juſqu’à 18. </s> <s xml:id="echoid-s4686" xml:space="preserve">ou 20. </s> <s xml:id="echoid-s4687" xml:space="preserve">pieds, on ne ſera pas <pb o="45" file="0223" n="229" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> obligé de faire les foſſés fort larges, parce qu’en les aprofondiſſant, <lb/>on aura toûjours des terres ſufiſamment, & </s> <s xml:id="echoid-s4688" xml:space="preserve">les ouvrages en ſeront <lb/>de meilleure défenſe, à cauſe qu’ils ſeront moins decouverts: </s> <s xml:id="echoid-s4689" xml:space="preserve">ſi au <lb/>contraire le terrain eſt aquatique, & </s> <s xml:id="echoid-s4690" xml:space="preserve">qu’on ne puiſſe s’enfoncer <lb/>auſſi avant qu’on le voudroit, ſans être incommodé des eaux; </s> <s xml:id="echoid-s4691" xml:space="preserve">alors <lb/>on prend ſur la largeur, ce que l’on ne peut tirer de la profondeur; <lb/></s> <s xml:id="echoid-s4692" xml:space="preserve">mais, je le repete, toutes ces conſiderations doivent dépendre du <lb/>projet, ainſi dans l’éxecution il ne s’agit que de bien diriger les atte-<lb/>liers. </s> <s xml:id="echoid-s4693" xml:space="preserve">Cet article demande beaucoup de circonſpection, & </s> <s xml:id="echoid-s4694" xml:space="preserve">quoique la <lb/>choſe ne paroiſſe qu’une bagatelle, je crois qu’on conviendra qu’on <lb/>n’a guere executé de grands travaux, ſans qu’il ne ſoit arrivé quelque <lb/>mal entendu dans le maniment des terres; </s> <s xml:id="echoid-s4695" xml:space="preserve">ici, faute d’en avoir fait <lb/>un amas aſſez conſiderable, avant d’élever les revêtemens, on eſt <lb/>obligé, pour achever l’ouvrage, d’en raporter par de longs circuits <lb/>qui augmentent les relais, par conſequent la depenſe; </s> <s xml:id="echoid-s4696" xml:space="preserve">là, pour n’y <lb/>avoir pas fait aſſés d’attention, il s’en trouve une trop grande quanti-<lb/>té, qu’il faut dans la ſuite tranſporter ailleurs, peut-être même auprès <lb/>de l’endroit d’où on les avoit tirées, deſorte qu’une toiſe cube, <lb/>qui n’auroit dû être maniée que deux fois, l’une pour la tranſpor-<lb/>ter, l’autre pour la mettre en œuvre, a été promenée à differens <lb/>endroits inutilement, ce qui en double ou triple la valeur; </s> <s xml:id="echoid-s4697" xml:space="preserve">au reſte <lb/>je ſai bien que cela n’arrive point à ceux qui ont une grande con-<lb/>noiſſance des travaux, parce qu’ils ſavent prevoir, dés le commen-<lb/>cement de l’ouvrage, les ſuites des moindres choſes.</s> <s xml:id="echoid-s4698" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4699" xml:space="preserve">Pour faire voir de quelle maniere on peut eſtimer aſſez juſte <lb/> <anchor type="note" xlink:label="note-0223-01a" xlink:href="note-0223-01"/> la quantité de terre deſtinée à la conſtruction d’un ouvrage, nous <lb/>ſupoſerons qu’on a tracé ſur un terrain bien uni, & </s> <s xml:id="echoid-s4700" xml:space="preserve">dans lequel on <lb/>peut aprofondir à ſec, un front de Poligone ABCDEF, dont <lb/>le foſſé eſt terminé par la Contreſcarpe GHI, & </s> <s xml:id="echoid-s4701" xml:space="preserve">que le rempart <lb/>qu’on veut élever eſt exprimé par le profil ABDKMX: </s> <s xml:id="echoid-s4702" xml:space="preserve">cela <lb/>poſé, comme la terre qu’on doit porter du côté de la place, & </s> <s xml:id="echoid-s4703" xml:space="preserve"><lb/>qu’on voit exprimé ici par KKK, &</s> <s xml:id="echoid-s4704" xml:space="preserve">c. </s> <s xml:id="echoid-s4705" xml:space="preserve">depend de l’élevation du <lb/>rempart; </s> <s xml:id="echoid-s4706" xml:space="preserve">nous ferons comme ſi le revêtement devoit avoir 30. </s> <s xml:id="echoid-s4707" xml:space="preserve">pieds <lb/>de hauteur, depuis le fonds du foſſé juſqu’au cordon, & </s> <s xml:id="echoid-s4708" xml:space="preserve">le foſſé <lb/>18. </s> <s xml:id="echoid-s4709" xml:space="preserve">pieds de profondeur; </s> <s xml:id="echoid-s4710" xml:space="preserve">en ce cas, pour que toutes les parties <lb/>du profil ſoient bien proportionnées, il faut que la hauteur BC, <lb/>du rempart, du côté de la place, ſoit de 12. </s> <s xml:id="echoid-s4711" xml:space="preserve">pieds & </s> <s xml:id="echoid-s4712" xml:space="preserve">demi, la <lb/>rampe AC, de 19. </s> <s xml:id="echoid-s4713" xml:space="preserve">& </s> <s xml:id="echoid-s4714" xml:space="preserve">demi, la largeur CE, de 30. </s> <s xml:id="echoid-s4715" xml:space="preserve">la hauteur <lb/>ED, de 14. </s> <s xml:id="echoid-s4716" xml:space="preserve">la rampe EG, de la banquette de 3. </s> <s xml:id="echoid-s4717" xml:space="preserve">ſa largeur GL, <lb/>de 4. </s> <s xml:id="echoid-s4718" xml:space="preserve">& </s> <s xml:id="echoid-s4719" xml:space="preserve">demi, & </s> <s xml:id="echoid-s4720" xml:space="preserve">la hauteur FG, ou HL, de 15. </s> <s xml:id="echoid-s4721" xml:space="preserve">& </s> <s xml:id="echoid-s4722" xml:space="preserve">demi, enfin le <lb/>parapet devant avoir 4. </s> <s xml:id="echoid-s4723" xml:space="preserve">pieds & </s> <s xml:id="echoid-s4724" xml:space="preserve">demi de hauteur, KN, ſera de <pb o="46" file="0224" n="230" rhead="LA SCIENCE DES INGENIEURS,"/> 20. </s> <s xml:id="echoid-s4725" xml:space="preserve">pieds, & </s> <s xml:id="echoid-s4726" xml:space="preserve">LN, d’un & </s> <s xml:id="echoid-s4727" xml:space="preserve">demi; </s> <s xml:id="echoid-s4728" xml:space="preserve">& </s> <s xml:id="echoid-s4729" xml:space="preserve">ſi l’on fait abſtraction des con-<lb/>treforts, & </s> <s xml:id="echoid-s4730" xml:space="preserve">qu’on ſupoſe pour abreger, que le revêtement ait 5. <lb/></s> <s xml:id="echoid-s4731" xml:space="preserve">pieds d’épaiſſeur au ſommet, MI, ſera de 18. </s> <s xml:id="echoid-s4732" xml:space="preserve">pieds, & </s> <s xml:id="echoid-s4733" xml:space="preserve">VI, de 13. </s> <s xml:id="echoid-s4734" xml:space="preserve"><lb/>Or ſi l’on cherche la ſuperficie de toutes les parties dont nous ve-<lb/>nons de donner les dimenſions, on trouvera qu’elles compoſent <lb/>enſemble 907. </s> <s xml:id="echoid-s4735" xml:space="preserve">pieds quarrés, d’où il faut retrancher la partie des <lb/>contreforts, qui eſt au-deſſus de la ligne horiſontale AT, après <lb/>en avoir fait la reduction, ainſi qu’on l’a enſeigné dans l’article 46. </s> <s xml:id="echoid-s4736" xml:space="preserve"><lb/>du premier livre, & </s> <s xml:id="echoid-s4737" xml:space="preserve">l’on trouvera qu’elle eſt équivalante à 26. </s> <s xml:id="echoid-s4738" xml:space="preserve">pieds <lb/>quarrés, qui étant retranchés de 907. </s> <s xml:id="echoid-s4739" xml:space="preserve">la difference ſera 881. </s> <s xml:id="echoid-s4740" xml:space="preserve">pieds <lb/>quarrés, quand on n’aura égard qu’au profil, mais qui deviendront <lb/>des pieds cubes, en ſupoſant que le profil a un pied dépaiſſeur. </s> <s xml:id="echoid-s4741" xml:space="preserve">Si <lb/>l’on veut ſavoir combien il faut de toiſes cubes de terre par toiſe <lb/>courante, on reduira les 881 pieds, en toiſes quarrées, pour avoir <lb/>environ 24. </s> <s xml:id="echoid-s4742" xml:space="preserve">toiſes & </s> <s xml:id="echoid-s4743" xml:space="preserve">demi, qui étant multipliées par une toiſe, <lb/>donnera 24. </s> <s xml:id="echoid-s4744" xml:space="preserve">pieds & </s> <s xml:id="echoid-s4745" xml:space="preserve">demi de toiſes cubes, c’eſt-à-dire, que ſi la <lb/>face d’un Baſtion à 50. </s> <s xml:id="echoid-s4746" xml:space="preserve">toiſes de longueur, il faudra à peu près <lb/>1225. </s> <s xml:id="echoid-s4747" xml:space="preserve">toiſes cubes de terre pour former cette face.</s> <s xml:id="echoid-s4748" xml:space="preserve"/> </p> <div xml:id="echoid-div265" type="float" level="3" n="2"> <note position="right" xlink:label="note-0223-01" xlink:href="note-0223-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>7.</note> </div> <p> <s xml:id="echoid-s4749" xml:space="preserve">Mais ſans s’embarraſſer de ce qu’il faut pour chaque partie du front, <lb/>il ſuffira après avoir trouvé la ſuperficie du profil ABDHKMI, <lb/>& </s> <s xml:id="echoid-s4750" xml:space="preserve">en avoir retranché les contreforts reduits, de diviſer 881. </s> <s xml:id="echoid-s4751" xml:space="preserve">pieds <lb/>par la profondeur qu’on veut donner au foſſé, c’eſt-à-dire par 18. <lb/></s> <s xml:id="echoid-s4752" xml:space="preserve">& </s> <s xml:id="echoid-s4753" xml:space="preserve">l’on trouvera environ 49. </s> <s xml:id="echoid-s4754" xml:space="preserve">pieds, pour la largeur RS, de la tran-<lb/>chée, qui, ayant 18. </s> <s xml:id="echoid-s4755" xml:space="preserve">pieds de profondeur fournira les terres neceſ-<lb/>ſaires à l’élevation du rempart; </s> <s xml:id="echoid-s4756" xml:space="preserve">ainſi traçant une ligne LMNOPQ, <lb/>paralelle aux parties du front ABCDEF, enſorte qu’elle ſoit éloignée <lb/>de 49, pieds du derriere de la muraille, on aura l’eſpace que doit oc-<lb/>cuper la tranchée dont je parle, puiſqu’une toiſe courante de la vui-<lb/>dange de cette tranchée fournira des terres pour une toiſe courante <lb/>de rampart, ce qui eſt bien évident, puiſque 6. </s> <s xml:id="echoid-s4757" xml:space="preserve">pieds de longueur, <lb/>49. </s> <s xml:id="echoid-s4758" xml:space="preserve">delargeur, & </s> <s xml:id="echoid-s4759" xml:space="preserve">18. </s> <s xml:id="echoid-s4760" xml:space="preserve">de profondeur, donnent 24. </s> <s xml:id="echoid-s4761" xml:space="preserve">toiſes & </s> <s xml:id="echoid-s4762" xml:space="preserve">demi cubes.</s> <s xml:id="echoid-s4763" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4764" xml:space="preserve">Selon l’eſtimation precedente, j’ai ſupoſé qu’il étoit queſtion des <lb/>Baſtions vuides, & </s> <s xml:id="echoid-s4765" xml:space="preserve">dont le terre-plain ſeroit de niveau avec le <lb/>rez-de-chauſſée de la place. </s> <s xml:id="echoid-s4766" xml:space="preserve">Si on avoit des raiſons pour le faire <lb/>autrement, ſoit pour y conſtruire des ſouterrains, ou y élever des <lb/>cavaliers, on pourra toûjours, en ſe reglant ſur les profils, ſavoir <lb/>de combien il faudra augmenter la largeur de la tranchée, pour <lb/>avoir une quantité de terre ſuffiſante, car j’entens qu’il faut toû-<lb/>jours en faire l’amas avant de conſtruire le revêtement.</s> <s xml:id="echoid-s4767" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4768" xml:space="preserve">A meſure que l’on fait le deblais des terres, on les porte à 8. <lb/></s> <s xml:id="echoid-s4769" xml:space="preserve">ou 10. </s> <s xml:id="echoid-s4770" xml:space="preserve">toiſes du côté de la place; </s> <s xml:id="echoid-s4771" xml:space="preserve">ſi le terrain eſt de bonne conſiſ- <pb o="47" file="0225" n="231" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> tance, & </s> <s xml:id="echoid-s4772" xml:space="preserve">qu’on ne craigne pas les éboullemens, on donne aux Ban-<lb/>quettes OP, qui doivent ſe trouver derriere le revêtement, le plus <lb/>de hauteur qu’il eſt poſſible, & </s> <s xml:id="echoid-s4773" xml:space="preserve">une largeur ſuffiſante ſeulement pour <lb/>ſe ſoûtenir, afin que quand la muraille ſera élevée, l’on n’ait que <lb/>peu de remblais à faire, ce qui diminuë la pouſſée des terres: </s> <s xml:id="echoid-s4774" xml:space="preserve">à l’é-<lb/>gard des Banquettes ST, qui ſe font du côté de la campagne, il faut <lb/>leur donner beaucoup plus de largeur que de hauteur, afin que les <lb/>travailleurs puiſſent les pratiquer commodement.</s> <s xml:id="echoid-s4775" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4776" xml:space="preserve">Quand on a creuſé juſqu’à la profondeur PS, que doit avoir le foſſé, <lb/>on fait une nouvelle tranchée PQRX, pour les fondemens de la <lb/>muraille, les terres qui en proviennent ſe jettent du côté de la cam-<lb/>pagne, & </s> <s xml:id="echoid-s4777" xml:space="preserve">ſe tranſportent, auſſi-bien que toutes celles qui étoient <lb/>reſtées dans le Foſſé, aux endroits marqués pour la conſtruction <lb/>des ouvrages de dehors; </s> <s xml:id="echoid-s4778" xml:space="preserve">on obſerve, à meſure qu’on en fait la <lb/>vuidange, de laiſſer des témoins de diſtance en diſtance, ou des <lb/>profils pour ſervir à faire les toiſés.</s> <s xml:id="echoid-s4779" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div267" type="section" level="2" n="85"> <head xml:id="echoid-head222" xml:space="preserve">CHAPITRE NEUVIE’ME.</head> <head xml:id="echoid-head223" style="it" xml:space="preserve">De la maniere de faire les Fondemens des Edifices dans toute <lb/>ſorte d’endroits, & principalement dans le mauvais terrain.</head> <p> <s xml:id="echoid-s4780" xml:space="preserve">IL ſemble qu’avant d’enſeigner la Conſtruction des Fondemens, <lb/>j’aurois dû dire quelque choſe ſur les précautions que l’on prend <lb/>pour ſe mettre en état de travailler dans les lieux aquatiques, ex-<lb/>pliquer la façon des batard’eaux que l’on conſtruit pour ſe garantir <lb/>des eaux étrangeres, ou pour faire des épuiſemens avec le ſecours <lb/>des machines que l’on a imaginées à cet uſage; </s> <s xml:id="echoid-s4781" xml:space="preserve">détailler les pro-<lb/>prietés de ces machines, afin de donner la préference à celles <lb/>dont on peut ſe ſervir le plus utilement: </s> <s xml:id="echoid-s4782" xml:space="preserve">c’eſt auſſi ce que j’ai fait <lb/>dans un Chapitre aſſés long que j’avois deſtiné à précéder imme-<lb/>diatement celui-ci; </s> <s xml:id="echoid-s4783" xml:space="preserve">mais ayant fait réfléxion que ſa véritable place <lb/>devoit être dans l’Architecture Hidraulique, c’eſt-à-dire dans le <lb/>ſecond tome de cet ouvrage, je m’en ſuis tenu à ce dernier parti; <lb/></s> <s xml:id="echoid-s4784" xml:space="preserve">c’eſt pourquoi j’y renvoye le Lecteur.</s> <s xml:id="echoid-s4785" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4786" xml:space="preserve">La premiere connoiſſance, dont il faut être prévenu, eſt la na-<lb/>ture des terrains qui ſe rencontrent en aprofondiſſant, & </s> <s xml:id="echoid-s4787" xml:space="preserve">quoique <lb/>leur diverſité ſoit très-grande, on peut cependant la réduire à trois <lb/>eſpeces principales. </s> <s xml:id="echoid-s4788" xml:space="preserve">La premiere eſt celle de tuf & </s> <s xml:id="echoid-s4789" xml:space="preserve">de roc: </s> <s xml:id="echoid-s4790" xml:space="preserve">ce der- <pb o="48" file="0226" n="232" rhead="LA SCIENCE DES INGENIEURS,"/> nier eſt facile à connoître par la réſiſtance que les Terraſſiers trou-<lb/>vent à foûiller.</s> <s xml:id="echoid-s4791" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4792" xml:space="preserve">La ſeconde eſpece de terrain eſt celle de Sable, dont on diſtin-<lb/>gue de deux ſortes; </s> <s xml:id="echoid-s4793" xml:space="preserve">l’un eſt le Sable ferme & </s> <s xml:id="echoid-s4794" xml:space="preserve">dur, ſur lequel on <lb/>n’héſite point à établir des fondemens; </s> <s xml:id="echoid-s4795" xml:space="preserve">& </s> <s xml:id="echoid-s4796" xml:space="preserve">l’autre le Sable mouvant, <lb/>dont le peu de conſiſtance ne permet pas qu’on travaille deſſus, <lb/>ſans prendre quelque précaution pour prévenir les accidens. </s> <s xml:id="echoid-s4797" xml:space="preserve">On dif-<lb/>tingue le Sable mouvant d’avec le ferme, par le moyen d’une ſonde <lb/>de fer, dont le bout eſt fait en tariere, afin de voir en la retirant <lb/>la nature dufond qu’elle a percée. </s> <s xml:id="echoid-s4798" xml:space="preserve">Lorſqu’elle réſiſte & </s> <s xml:id="echoid-s4799" xml:space="preserve">qu’elle entre <lb/>avec peine, c’eſt une marque que le Sable eſt dur; </s> <s xml:id="echoid-s4800" xml:space="preserve">au lieu qu’on <lb/>doit juger du contraire, ſielle entre facilement: </s> <s xml:id="echoid-s4801" xml:space="preserve">quand on eſt obligé <lb/>de foüiller fort avant pour rencontrer le bon fonds, on allonge la <lb/>ſonde par le moyen de pluſieurs branches de fer qui s’ajuſtent bout <lb/>à bout avec des vis en écrouës. </s> <s xml:id="echoid-s4802" xml:space="preserve">Il ſe rencontre dans les lieux aquati-<lb/>ques un Sable d’où il ſort de l’eau quand on marche deſſus, ce qui <lb/>l’a fait nommer Sable boüillant, qu’on ne doit point confondre avec <lb/>le mouvant, puiſqu’il s’en trouve ſouvent ſur lequel on peut aſſéoir <lb/>des fondemens très-ſolides, comme nous le ferons voir ailleurs.</s> <s xml:id="echoid-s4803" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4804" xml:space="preserve">La troiſiéme eſt celle de terre, dont on diſtingue de quatre ſor-<lb/>tes, la terre ordinaire, la graſſe, la glaiſe, & </s> <s xml:id="echoid-s4805" xml:space="preserve">celle detourbe. </s> <s xml:id="echoid-s4806" xml:space="preserve">La terre <lb/>ordinaire ſe trouve dans les lieuxſecs & </s> <s xml:id="echoid-s4807" xml:space="preserve">élevés: </s> <s xml:id="echoid-s4808" xml:space="preserve">la terre graſſe eſt preſ-<lb/>que toûjours compoſée de vaſe ſans conſiſtance, & </s> <s xml:id="echoid-s4809" xml:space="preserve">ne ſe trouve guére <lb/>que dans les lieux bas, on ne peut y fonder qu’avec de grandes <lb/>précautions: </s> <s xml:id="echoid-s4810" xml:space="preserve">pour la glaiſe, elle ſe trouve indifferemment dans les <lb/>lieux hauts & </s> <s xml:id="echoid-s4811" xml:space="preserve">bas; </s> <s xml:id="echoid-s4812" xml:space="preserve">quand elle eſt ferme & </s> <s xml:id="echoid-s4813" xml:space="preserve">qu’elle forme un banc <lb/>d’une épaiſſeur conſidérable, on peut y fonder hardiment, pourvû <lb/>qu’on ſoit ſûr qu’elle ſe trouve par-tout d’une égale conſiſtance, ſans <lb/>quoi il faudroit prendre des meſures convenables à la neceſſité: <lb/></s> <s xml:id="echoid-s4814" xml:space="preserve">pour la terre de tourbe, elle ne ſe trouve que dans les lieux aquati-<lb/>ques & </s> <s xml:id="echoid-s4815" xml:space="preserve">marécageux; </s> <s xml:id="echoid-s4816" xml:space="preserve">c’eſt une eſpece de terre graſſe, noire, & </s> <s xml:id="echoid-s4817" xml:space="preserve">bi-<lb/>tumineuſe, qui ſe conſume au feu après l’avoir fait ſécher, & </s> <s xml:id="echoid-s4818" xml:space="preserve">dont <lb/>l’uſage eſt très-commun aux Pays-Bas: </s> <s xml:id="echoid-s4819" xml:space="preserve">il y a des gens qui prétendent <lb/>que cette terre provient des differens accroiſſemens que certains <lb/>cantons ont reçûs en s’élevant par la ſuite des tems; </s> <s xml:id="echoid-s4820" xml:space="preserve">ce qui favo-<lb/>riſe cette opinion eſt qu’ayant foüillé dans un terrain tourbeux, on <lb/>y a trouvé des arbres d’une groſſeur conſidérable, & </s> <s xml:id="echoid-s4821" xml:space="preserve">tous les autres <lb/>veſtiges d’un lieu qui a été autrefois découvert: </s> <s xml:id="echoid-s4822" xml:space="preserve">au reſte, il n’eſt <lb/>point aſſés ſolide pour y aſſéoir des fondemens, à moins qu’on n’ait <lb/>recours à ce que l’art & </s> <s xml:id="echoid-s4823" xml:space="preserve">l’induſtrie peuvent fournir en pareil cas.</s> <s xml:id="echoid-s4824" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4825" xml:space="preserve">Indépendamment des ſoins qu’on doit prendre pour avoir une <pb file="0227" n="233"/> <pb file="0227a" n="234"/> <anchor type="figure" xlink:label="fig-0227a-01a" xlink:href="fig-0227a-01"/> <pb file="0228" n="235"/> <pb o="49" file="0229" n="236" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> parfaite connoiſſance du fond ſur lequel on veut travailler, il eſt <lb/>bon de queſtionner les Ouvriers du Pays, il s’en rencontre toûjours <lb/>quelques-uns à qui le bon ſens, & </s> <s xml:id="echoid-s4826" xml:space="preserve">l’uſage continuel où ils ſont de <lb/>travailler dans un même endroit, ont fait faire des remarques & </s> <s xml:id="echoid-s4827" xml:space="preserve">des <lb/>réfléxions, dont il eſt bon qu’on ſoit prévenû: </s> <s xml:id="echoid-s4828" xml:space="preserve">ſouvent ces gens-là <lb/>donnent plus de connoiſſance dans un quart-d’heure, qu’on ne pour-<lb/>roit en acquerir par de longues & </s> <s xml:id="echoid-s4829" xml:space="preserve">pénibles recherches.</s> <s xml:id="echoid-s4830" xml:space="preserve"/> </p> <div xml:id="echoid-div267" type="float" level="3" n="1"> <figure xlink:label="fig-0227a-01" xlink:href="fig-0227a-01a"> <image file="0227a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0227a-01"/> </figure> </div> <p> <s xml:id="echoid-s4831" xml:space="preserve">Nous propoſant de faire voir la maniere de fonder ſurtoute ſorte <lb/>de terrain, les differens moyens, qu’on va inſinuer, pourront s’a-<lb/>pliquer à la Conſtruction des Edifices en general: </s> <s xml:id="echoid-s4832" xml:space="preserve">cependant, comme <lb/>nous avons principalement en vûë les ouvrages de Fortifications, on <lb/>s’attachera plûtôt à donner des exemples qui leur ſoient aplicables, <lb/>qu’à toute autre eſpece de Travaux; </s> <s xml:id="echoid-s4833" xml:space="preserve">c’eſt pourquoi les deſſeins de <lb/>la huitiéme planche repréſentent des profils de remparts.</s> <s xml:id="echoid-s4834" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4835" xml:space="preserve">Les fondemens, qui ſe font à ſec, ſont aſſis ſur le roc, ou ſur un <lb/>bon fond; </s> <s xml:id="echoid-s4836" xml:space="preserve">quand on fonde ſur le roc, on établit les aſſiſes par ref-<lb/> <anchor type="note" xlink:label="note-0229-01a" xlink:href="note-0229-01"/> ſauts s’il faut monter ou deſcendre, leur donnant le plus d’aſſiette <lb/>qu’il eſt poſſible, & </s> <s xml:id="echoid-s4837" xml:space="preserve">un pouce ou un pouce & </s> <s xml:id="echoid-s4838" xml:space="preserve">demide pente du de-<lb/>vant au derriere, afin que la Maçonnerie qu’on veut élever ſe ſoû-<lb/> <anchor type="note" xlink:label="note-0229-02a" xlink:href="note-0229-02"/> tienne parfaitement. </s> <s xml:id="echoid-s4839" xml:space="preserve">Si le roc eſt trop uni, & </s> <s xml:id="echoid-s4840" xml:space="preserve">qu’on aprehende que <lb/> <anchor type="note" xlink:label="note-0229-03a" xlink:href="note-0229-03"/> la Maçonnerie ne faſſe pas de bons arpemens, on le pique à coups <lb/>de marteau têtu, & </s> <s xml:id="echoid-s4841" xml:space="preserve">après avoir bien nétoïé les decombres, on l’af-<lb/>ſéoit en bain de bon mortier, & </s> <s xml:id="echoid-s4842" xml:space="preserve">on l’encaſtre de quelques pouces. <lb/></s> <s xml:id="echoid-s4843" xml:space="preserve">Si le roc ſur lequel on veut fonder, eſt diſpoſé de maniere que ſa <lb/>hauteur puiſſe faire partie du mur, on lui addoſſe la Maçonnerie, <lb/>& </s> <s xml:id="echoid-s4844" xml:space="preserve">on y fait des écorchemens pour que l’un & </s> <s xml:id="echoid-s4845" xml:space="preserve">l’autre puiſſent ſe <lb/>bien lier enſemble; </s> <s xml:id="echoid-s4846" xml:space="preserve">par exemple, après avoir creuſé les Foſſez d’une <lb/>Fortereſſe, on en revêtit ſon eſcarpe & </s> <s xml:id="echoid-s4847" xml:space="preserve">ſa contreſcarpe, & </s> <s xml:id="echoid-s4848" xml:space="preserve">au lieu <lb/>qu’on auroit donné à la baſe du mur 10 ou 12 pieds, dans tout au-<lb/>tre terrain, on ſe contente de ne lui en donner que quatre ou cinq <lb/>ſuivant les reſſauts qu’on a formés, parce qu’alors n’ayant pas de grands <lb/>remblais à faire, les revêtemens n’ont que peu de pouſſée, & </s> <s xml:id="echoid-s4849" xml:space="preserve">même <lb/>quelquefois point du tout.</s> <s xml:id="echoid-s4850" xml:space="preserve"/> </p> <div xml:id="echoid-div268" type="float" level="3" n="2"> <note position="right" xlink:label="note-0229-01" xlink:href="note-0229-01a" xml:space="preserve">Fonde-<lb/>ment ſur <lb/>le Roc.</note> <note position="right" xlink:label="note-0229-02" xlink:href="note-0229-02a" xml:space="preserve"><emph style="sc">Planch</emph> <lb/>8.</note> <note position="right" xlink:label="note-0229-03" xlink:href="note-0229-03a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s4851" xml:space="preserve">Ces ſortes de revêtemens, quoiqu’aiſés à conſtruire en apparen-<lb/>ce, à cauſe qu’on n’a rien à apprehender de la part du fonds, ren-<lb/>contrent ſouvent bien des difficultés dans l’execution, quand ils’agit <lb/>d’élever quelque Fortereſſe au ſommet d’un rocher eſcarpé, oùl’on <lb/>ne peut faire quatre toiſes d’ouvrages ſans monter ou deſcendre, <lb/>& </s> <s xml:id="echoid-s4852" xml:space="preserve">où il faut quelquefois 10 ou 12 profils differens pour executer une <lb/>ſeule piece. </s> <s xml:id="echoid-s4853" xml:space="preserve">Les Ingenieurs, qui font travailler dans le Rouſſillon & </s> <s xml:id="echoid-s4854" xml:space="preserve"><lb/>dans les autres endroits Montagneux, ſeroient ſeuls capables de <pb o="50" file="0230" n="237" rhead="LA SCIENCE DES INGENIEURS,"/> donner de bonnes inſtructions pour ſe conduire dans deſemblables <lb/>terrains: </s> <s xml:id="echoid-s4855" xml:space="preserve">je crois même qu’il n’y a guére que ſur les lieux qu’on peut <lb/>s’appercevoir des differentes pratiques dont on ſera obligé de ſe ſer-<lb/>vir, la neceſſité, avec un peu de génie, fourniſſant mille moyens pour <lb/>ſurmonter les obſtacles à meſure qu’ils ſe preſentent. </s> <s xml:id="echoid-s4856" xml:space="preserve">J’ai toûjours <lb/>regardé ce Chapitre comme le plus difficile de ceux que j’avois à <lb/>traiter, puiſque, pour le rendre complet, il m’auroit falu de bons <lb/>Mémoires generalement de tous les Ingenieurs en chef qui ſont <lb/>dans nos places; </s> <s xml:id="echoid-s4857" xml:space="preserve">car il y a cela de fâcheux, qu’on ne peut paſſer de <lb/>l’un à l’autre, ſans rencontrer quelque changement dans la maniere <lb/>de travailler, ce qui vient de la difference du terrain ou de la qualité <lb/>des matériaux: </s> <s xml:id="echoid-s4858" xml:space="preserve">mais ſi j’avois voulu embraſſer toutes les parties d’un <lb/>ſujet auſſi vaſte que celui-ci, & </s> <s xml:id="echoid-s4859" xml:space="preserve">en faire de même pour les autres, <lb/>j’aurois été obligé d’entrer dans un détail immenſe quim’auroit en-<lb/>gagé (non pas à faire un Livre) mais une Bibliotheque; </s> <s xml:id="echoid-s4860" xml:space="preserve">il a donc <lb/>falu m’en tenir aux pratiques les plus eſſentielles, dans l’eſperance <lb/>que l’on me feroit grace de tout ce qui meritoit moins d’attention.</s> <s xml:id="echoid-s4861" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4862" xml:space="preserve">Quand on eſt obligé d’établir des murs ſur unroc fort inégal par <lb/>fa figure, & </s> <s xml:id="echoid-s4863" xml:space="preserve">quelquefois par ſa conſiſtance, la plus grande difficulté <lb/>eſt de r’accorder à une certaine hauteur les premieres aſſiſes de <lb/>Maçonnerie qui doivent ſervir de Fondemens, & </s> <s xml:id="echoid-s4864" xml:space="preserve">de les bien lier <lb/>avec le roc: </s> <s xml:id="echoid-s4865" xml:space="preserve">de tous les moyens qui ſont venus à ma connoiſſance <lb/>& </s> <s xml:id="echoid-s4866" xml:space="preserve">dont on peut ſe ſervir en pareil cas, en voici un entr’autres pour <lb/>lequel je pencherai beaucoup, & </s> <s xml:id="echoid-s4867" xml:space="preserve">dont on s’eſt bien trouvé dans la <lb/>conſtruction de pluſieurs grands ouvrages.</s> <s xml:id="echoid-s4868" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4869" xml:space="preserve">Après avoir établi le terrain de la maniere qu’on le jugera le plus <lb/> <anchor type="note" xlink:label="note-0230-01a" xlink:href="note-0230-01"/> convenable, & </s> <s xml:id="echoid-s4870" xml:space="preserve">avoir reglé l’épaiſſeur qu’il faudra donner aux fon-<lb/>demens, par raport à l’élevation de la muraille, il faut en border <lb/>les allignemens avec des cloiſons de Charpente, enſorte qu’elles <lb/>compoſent enſemble un coffre dont le bord ſuperieur ſoit diſpoſé <lb/> <anchor type="note" xlink:label="note-0230-02a" xlink:href="note-0230-02"/> le plus horiſontalement qu’il ſe pourra; </s> <s xml:id="echoid-s4871" xml:space="preserve">car pour le bas il doit ſuivre <lb/>la figure des reſſauts & </s> <s xml:id="echoid-s4872" xml:space="preserve">des differentes ſinuoſités qu’on aura été obligé <lb/>de donner au roc: </s> <s xml:id="echoid-s4873" xml:space="preserve">ayant fait un grand amas de pierrailles, il faut <lb/>les corroyer avec du mortier; </s> <s xml:id="echoid-s4874" xml:space="preserve">on pourra même ſi le roc eſt bon ſe <lb/>ſervir des décombres qu’on en aura tirés après avoir réduit les plus <lb/>forts quartiers à une groſſeur médiocre qui ne doit pas paſſer celle <lb/>du poing: </s> <s xml:id="echoid-s4875" xml:space="preserve">il faut le lendemain, ou au plus tard deux jours après qu’on <lb/>aura fait pluſieurs tas de mortier de pierrées, avoir un grand nom-<lb/>bre de Manœuvres dont les uns rempliront les coffres de ce mor-<lb/>tier, tandis que les autres le battront à meſure que la Maçonne-<lb/>rie s’élevera avec des dames du poids de 30 livres ferrées par le <pb o="51" file="0231" n="238" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> bout; </s> <s xml:id="echoid-s4876" xml:space="preserve">(je crois qu’il n’eſt pas beſoin de dire qu’elle doit être aſſiſe <lb/>immédiatement ſur le roc dans lequel elle doit être encaſtrée de 7 <lb/>ou 8 pouces) lorſqu’elle a pris conſiſtance & </s> <s xml:id="echoid-s4877" xml:space="preserve">qu’elle eſt fuffiſam-<lb/>ment ſéche, on détache les cloiſons pour s’en ſervir ailleurs; </s> <s xml:id="echoid-s4878" xml:space="preserve">j’a-<lb/>joûterai que quand on eſt obligé de faire quelque caſcade pour <lb/>monter ou deſcendre, on ſoûtient la Maçonnerie parles côtez avec <lb/>d’autres cloiſons diſpoſées en gradins, ainſi on ſurmonte le roc par <lb/>des fondemens auſquels on donne la figure que l’on veut; </s> <s xml:id="echoid-s4879" xml:space="preserve">car l’on <lb/>doit entendre que j’apelle ici fondement, la Maçonnerie qui ſert <lb/>d’empattement à celle que l’on veut élever par aſſiſe reglée, quoi-<lb/>que cet empattement ne ſoit point enterré comme les fondemens <lb/>ordinaires. </s> <s xml:id="echoid-s4880" xml:space="preserve">Je n’en détermine point la hauteur, qui ſera ſil’on veut <lb/>de 3 à 4 pieds plus ou moins ſelon la neceſſité.</s> <s xml:id="echoid-s4881" xml:space="preserve"/> </p> <div xml:id="echoid-div269" type="float" level="3" n="3"> <note position="left" xlink:label="note-0230-01" xlink:href="note-0230-01a" xml:space="preserve">Fonde-<lb/>ment de <lb/>pierrée.</note> <note position="left" xlink:label="note-0230-02" xlink:href="note-0230-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 11. <lb/>& 12.</note> </div> <p> <s xml:id="echoid-s4882" xml:space="preserve">Pour que toutes les parties des fondemens ſoient bien liées en-<lb/>ſemble & </s> <s xml:id="echoid-s4883" xml:space="preserve">parfaitement unies avec le roc, il faut remplir les coffres <lb/>ſans interruption ſur l’étenduë qu’on a jugé à propos d’embraſſer, <lb/>obſervant de faire battre également par-tout, particulierement dans <lb/>le commencement, afin que le mortier & </s> <s xml:id="echoid-s4884" xml:space="preserve">les pierres s’inſinuent <lb/>dans les écorchemens qui ſe trouveront figurés dans le roc, ſoit par <lb/>le hazard, ou parce qu’on aura jugé à propos de les faire exprès, <lb/>pour rendre la liaiſon plus parfaite.</s> <s xml:id="echoid-s4885" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4886" xml:space="preserve">Quand le roc eſt fort eſcarpé, on peut, pour ne point faire de rem-<lb/>blais derriere les fondemens, ſe contenter d’établir une ſeule cloi-<lb/>ſon ſur le devant pour ſoûtenir la Maçonnerie & </s> <s xml:id="echoid-s4887" xml:space="preserve">remplir de pier-<lb/>rées l’intervalle qui ſe trouve depuis-là juſqu’à l’eſcarpement, ce <lb/>qui rendra l’ouvrage encore plus ſolide.</s> <s xml:id="echoid-s4888" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4889" xml:space="preserve">Quand on a établi & </s> <s xml:id="echoid-s4890" xml:space="preserve">bien arraſé, à la hauteur convenable, les <lb/>fondemens ſur toute l’étenduë qu’on a embraſſée, on continuë à re-<lb/>peter la même manœuvre ſur le prolongement de l’ouvrage, ob-<lb/>ſervant de bien lier la vieille Maçonnerie avec la nouvelle; </s> <s xml:id="echoid-s4891" xml:space="preserve">c’eſt-à-<lb/>dire les pierrées faites depuis quelque-tems avec celle qu’on voudra <lb/>y ajoûter; </s> <s xml:id="echoid-s4892" xml:space="preserve">pour cela, il faudra toûjours faire en rampe les extrêmités <lb/>des fondemens qu’on ſaura devoir être prolongés, jetter de l’eau <lb/>deſſus, & </s> <s xml:id="echoid-s4893" xml:space="preserve">bien battre la nouvelle Maçonnerie à meſure qu’elle ſera <lb/>apliquée ſur la vieille.</s> <s xml:id="echoid-s4894" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4895" xml:space="preserve">De cette maniere l’on fera des fondemens, qui, venant à ſe durcir <lb/>peu à peu, ne compoſeront par-tout qu’un ſeul corps ſi ferme & </s> <s xml:id="echoid-s4896" xml:space="preserve"><lb/>ſi inébranlable, qu’il ne faut pas aprehender qu’il ſe faſſe par la ſuite <lb/>aucun affaiſſement ni rupture, ſoit qu’ils ſe trouvent inégalement <lb/>chargés par le poids de la muraille qu’on aura élevée deſſus, ou que <lb/>certaine partie du terrain moins ſolide que l’autre céde ou ſe dé-<lb/>tache, comme cela arrive quelquefois.</s> <s xml:id="echoid-s4897" xml:space="preserve"/> </p> <pb o="52" file="0232" n="239" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s4898" xml:space="preserve">Quand on eſt dans un Pays où la Chaux eſt bonne, je ſuis per-<lb/>ſuadé que detoutesles Maçonneries, il ny en a point de plus excel-<lb/>lente que celle que je viens de décrire, & </s> <s xml:id="echoid-s4899" xml:space="preserve">qui ſoit plus commode <lb/>dans une infinité d’occaſions, ſouvent l’on creuſe des fondemens <lb/>dans un terrain qui ſera ferme en un endroit & </s> <s xml:id="echoid-s4900" xml:space="preserve">douteux à quelque <lb/>pas plus loin, ce qui eſt cauſe que les murs s’affaiſſent inégalement; <lb/></s> <s xml:id="echoid-s4901" xml:space="preserve">ſi les fondemens ſont faits de pierrées, il ne faut pas apprehender <lb/>qu’étant d’une certaine épaiſſeur, il ſe faſſe jamais quelque rupture, <lb/>quand bien même il y auroit des parties qui porteroient à faux, ce <lb/>que l’on ne peut pas attendre de la Maçonnerie ordinaire, ſur-tout <lb/>quand elle eſt faite de groſſes pierres, à cauſe que le mortier s’y at-<lb/>tache moins & </s> <s xml:id="echoid-s4902" xml:space="preserve">ſujet à taſſer plus en un endroit qu’à l’autre: </s> <s xml:id="echoid-s4903" xml:space="preserve">c’eſt <lb/>ce qui a fait dire à Vitruve, que la Maçonnerie faite avec de petites <lb/>pierres étoit plus indiſſoluble que les autres. </s> <s xml:id="echoid-s4904" xml:space="preserve">Mr. </s> <s xml:id="echoid-s4905" xml:space="preserve">Perrault, dans le <lb/>Commentaire qu’il a fait de cet Auteur, fait voir en pluſieurs en-<lb/>droits de ſes Notes, que les Anciens faiſoient ſouvent de la Maçon-<lb/>nerie de pierrées, non-ſeulement pour les Fondations épineuſes, <lb/>mais encore dans une infinité d’occaſions, comme on en peut ju-<lb/>ger par les monumens qui reſtent, où l’on remarque que tous les <lb/>Ouvrages faits dans ce goût-là ſe ſont durcis au point de ſurpaſſer <lb/>la ſolidité du marbre: </s> <s xml:id="echoid-s4906" xml:space="preserve">car il faut convenir, qu’il n’y a point de pierre <lb/>ſi dure qu’elle puiſſe être qu’on ne rompe, & </s> <s xml:id="echoid-s4907" xml:space="preserve">dont on ne tire aiſé-<lb/>ment des éclats; </s> <s xml:id="echoid-s4908" xml:space="preserve">au lieu que d’un maſſif fait de mortier de pierrées, <lb/>on n’en peut ſéparer les parties que ſucceſſivement.</s> <s xml:id="echoid-s4909" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4910" xml:space="preserve">Quand on eſt dans un Pays où la pierre dure eſt fort rare, je <lb/>crois qu’on pourroit en toute ſeureté faire les ſoûbaſſemens des <lb/>gros murs avec une bonne pierrée, la difficulté eſt ſeulement d’a-<lb/>voir d’excellente Chaux: </s> <s xml:id="echoid-s4911" xml:space="preserve">il eſt vrai que la grande quantité qu’il en <lb/>faut rend cette Maçonnerie fort chere; </s> <s xml:id="echoid-s4912" xml:space="preserve">mais cela ne doit point en <lb/>diminuer le mérite quand il s’agit d’un Ouvrage de conſequence: <lb/></s> <s xml:id="echoid-s4913" xml:space="preserve">on en voit perir tous les jours pour y avoir regardé de trop près en <lb/>les conſtruiſant, & </s> <s xml:id="echoid-s4914" xml:space="preserve">quand il faut les réparer, on s’aperçoit trop tard <lb/>des inconveniens d’une œconomie mal-entenduë; </s> <s xml:id="echoid-s4915" xml:space="preserve">cependant, tout <lb/>bien conſideré, la Maçonnerie de pierrée ne coûtera jamais celle <lb/>de Pierre de Taille, l’on pourroit ſeulement trouver à redire que <lb/>voulant l’employer pour des ſoûbaſſemens ou pour des fondemens <lb/>découverts, le coup d’œil ne ſeroit point ſatisfait de voir un pare-<lb/>ment brut, & </s> <s xml:id="echoid-s4916" xml:space="preserve">d’une aſſés vilaine figure; </s> <s xml:id="echoid-s4917" xml:space="preserve">mais il eſt aiſé d’empêcher <lb/>cela, en faiſant avant la conſtruction deux eſpeces de mortier, l’un <lb/>mêlé de pierrailles comme celui dont nous venons de parler, & </s> <s xml:id="echoid-s4918" xml:space="preserve"><lb/>l’autre de gros graviers: </s> <s xml:id="echoid-s4919" xml:space="preserve">ſi l’on étoit dans un Pays où il y eût deux <pb o="53" file="0233" n="240" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> ſortes de Chaux, il faudroit employer la meilleure pour la compo-<lb/>ſition de ce dernier, & </s> <s xml:id="echoid-s4920" xml:space="preserve">la moindre pour celle de l’autre, & </s> <s xml:id="echoid-s4921" xml:space="preserve">les <lb/>employer comme il ſuit.</s> <s xml:id="echoid-s4922" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4923" xml:space="preserve">Quand on travaillera ſur le roc, on commencera à jetter au fond <lb/>du coffre un lit de mortier fin, parce qu’il s’y attachera mieux que <lb/>l’autre; </s> <s xml:id="echoid-s4924" xml:space="preserve">enſuite des manœuvres qui doivent remplir le coffre, on en <lb/>choiſira un nombre pour porter du mortier fin, lui recommandant <lb/>de le jetter contre le bord interieur du coffre, j’entends contre le <lb/>bord qui ſoûtient le parement, & </s> <s xml:id="echoid-s4925" xml:space="preserve">le reſte ſera rempli de mortier <lb/>de pierrée: </s> <s xml:id="echoid-s4926" xml:space="preserve">ſi cela eſt bien conduit, le mortier fin ſe liant avec l’au-<lb/>tre formera contre la cloiſon un parement uni, qui, venant à ſe <lb/>durcir, fera le même effet que la pierre; </s> <s xml:id="echoid-s4927" xml:space="preserve">on pourra même, ſi l’on <lb/>veut, au bout de quelque tems, pour une plus grande imitation, y fi-<lb/>gurer des joints.</s> <s xml:id="echoid-s4928" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4929" xml:space="preserve">Les Fondemens, qui ſe font encore à ſec ſur un terrain de bonne <lb/> <anchor type="note" xlink:label="note-0233-01a" xlink:href="note-0233-01"/> conſiſtance, & </s> <s xml:id="echoid-s4930" xml:space="preserve">qui ne preſente aucun obſtacle conſiderable à ſur-<lb/>monter, ſe conſtruiſent ſans beaucoup de miſtere. </s> <s xml:id="echoid-s4931" xml:space="preserve">On prépare le <lb/>terrain comme on l’a veu dans le Chapitre précédent, & </s> <s xml:id="echoid-s4932" xml:space="preserve">après avoir <lb/>creuſé la tranchée de la largeur & </s> <s xml:id="echoid-s4933" xml:space="preserve">de la profondeur déterminées par <lb/>les profils, on lui donne un talud allant du devant au derriere, pro-<lb/>portionné à l’épaiſſeur que doivent avoir les fondemens, afin que <lb/>le revêtement ſoûtienne mieux la pouſſée des terres. </s> <s xml:id="echoid-s4934" xml:space="preserve">Par exemple <lb/>ſur 12 pieds d’épaiſſeur, on donnera 6 pouces de talud, ainſi des <lb/>autres dont le talud ſera toûjours à peu-près la 24 partie de l’épaiſ-<lb/>ſeur: </s> <s xml:id="echoid-s4935" xml:space="preserve">on établit la premiere aſſiſe de gros libages plats poſés en bain <lb/>de bon mortier (quoique bien des gens aiment mieux les poſer à <lb/>ſec, leur entre-deux garni de mortier) ſur cette premiere aſſiſe on <lb/>en éleve une autre dont les allignemens ſont compoſés de boutiſſes <lb/>& </s> <s xml:id="echoid-s4936" xml:space="preserve">de pannereſſes en liaiſon alternative, les boutiſſes ayant au moins <lb/>18 pouces de queuës & </s> <s xml:id="echoid-s4937" xml:space="preserve">d’une groſſeur raiſonnable principalement <lb/>ſur le devant; </s> <s xml:id="echoid-s4938" xml:space="preserve">car pour le derriere on ſe contente d’y poſer les plus <lb/>gros quartiers de pierre, le milieu ſe remplit de moîlons à bain de <lb/>mortier; </s> <s xml:id="echoid-s4939" xml:space="preserve">quand il eſt brut, les intervalles ſe garniſſent par le petit <lb/>moîlon enfoncé dans les joints le plus avant qu’on peut, & </s> <s xml:id="echoid-s4940" xml:space="preserve">bien arraſé, <lb/>on continuë de même pour les autres aſſiſes, obſervant tant qu’il ſe <lb/>peut de conduire l’ouvrage de niveau ſur toute ſa longueur: </s> <s xml:id="echoid-s4941" xml:space="preserve">on fait <lb/>obſerver aux Maçons des retraites du côté du Foſſé, de maniere que <lb/>le prolongement du talud de la muraille qu’on veut élever ne porte <lb/>point à faux, & </s> <s xml:id="echoid-s4942" xml:space="preserve">afin qu’ils puiſſent mieuxſe conformer au profil qui <lb/>en aura été fait, il eſt à propos de leur en donner un deſſein en grand, <lb/>exactement cotté, pour qu’ils ſachent la hauteur & </s> <s xml:id="echoid-s4943" xml:space="preserve">la largeur des re- <pb o="54" file="0234" n="241" rhead="LA SCIENCE DES INGENIEURS,"/> traites, cette partie de l’ouvrage étant de conſéquence.</s> <s xml:id="echoid-s4944" xml:space="preserve"/> </p> <div xml:id="echoid-div270" type="float" level="3" n="4"> <note position="right" xlink:label="note-0233-01" xlink:href="note-0233-01a" xml:space="preserve">Fonde-<lb/>ment ſur <lb/>un terrain <lb/>ordinaire <lb/>& de bon-<lb/>ne conſi-<lb/>ſtance.</note> </div> <p> <s xml:id="echoid-s4945" xml:space="preserve">Quoique le bon fond ſe trouve ordinairement plûtôt ſur les ter-<lb/>rains élevés, que dans les autres bas & </s> <s xml:id="echoid-s4946" xml:space="preserve">aquatiques, il s’en rencontre <lb/>pourtant d’excellents dans ces derniers, comme ſont ceux de gra-<lb/>vier, de marne, de glaiſe, d’autres d’une certaine terre bleuâtre <lb/>qui eſt le plus ſouvent de bonne conſiſtance, j’y comprendrai même <lb/>le Sable boüillant qui eſt fort bon quand on ſait s’y conduire avec <lb/>adreſſe: </s> <s xml:id="echoid-s4947" xml:space="preserve">on établit des fondemens ſur tout ces terrains avec aſſés <lb/>de confiance, c’eſt pourquoi je ne m’y arrêterai pas.</s> <s xml:id="echoid-s4948" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4949" xml:space="preserve">L’on eſt quelquefois contraint de creuſer ſi avant pour trouver <lb/>le bon fond, qu’on ne peut élever les fondemens juſqu’au rez-de-<lb/>Chauſſée ſans des dépenſes extraordinaires; </s> <s xml:id="echoid-s4950" xml:space="preserve">en ce cas, Philbert de <lb/>Lorme, Scamozzy, & </s> <s xml:id="echoid-s4951" xml:space="preserve">pluſieurs autres Architectes après eux, pro-<lb/>poſent de faire des piliers de diſtance en diſtance pour y élever des <lb/>décharges, afin qu’à peu de frais l’on puiſſe gagner le rez-de-<lb/>Chauſſée.</s> <s xml:id="echoid-s4952" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s4953" xml:space="preserve">Comme le terrain, ſur lequel on voudroit fonder les piles, peut <lb/> <anchor type="note" xlink:label="note-0234-01a" xlink:href="note-0234-01"/> ſe trouver d’inégale réſiſtance, il ſeroit à craindre que par la <lb/>ſuite le terrain de deſſous, quelques piles venant à s’affaiſſer, ne cau-<lb/>ſàt une grande rupture aux arcades, par conſéquent aux murs qui <lb/>ſeroient élevés deſſus: </s> <s xml:id="echoid-s4954" xml:space="preserve">pour prévenir cet inconvenient on a crû que <lb/>le meilleur moyen étoit de faire, entre les piles, des arcades renver-<lb/>ſées, afin que ſi une des piles étoit moins aſſurée que les autres, elle <lb/>ſe trouvât arcboutée par les arcades voiſines, qui ne pouvant cé-<lb/>der à cauſe qu’elles ſont ſoûtenuës par les terres qui ſont au-deſ-<lb/>ſous, il n’eſt pas poſſible que la pile puiſſe changer de ſituation, <lb/>quand bien même elle porteroit à faux.</s> <s xml:id="echoid-s4955" xml:space="preserve"/> </p> <div xml:id="echoid-div271" type="float" level="3" n="5"> <note position="left" xlink:label="note-0234-01" xlink:href="note-0234-01a" xml:space="preserve">Fonde-<lb/>ment par <lb/>arcades ou <lb/>décharges.</note> </div> <p> <s xml:id="echoid-s4956" xml:space="preserve">Il arrive ſouvent, qu’en voulant établir des Fondemens on ren-<lb/> <anchor type="note" xlink:label="note-0234-02a" xlink:href="note-0234-02"/> contre des ſources qui incommodent beaucoup le travail: </s> <s xml:id="echoid-s4957" xml:space="preserve">il y a des <lb/>gens qui prétendent les éteindre, en jettant deſſus quantité de cen-<lb/>dre mêlée de Chaux vive; </s> <s xml:id="echoid-s4958" xml:space="preserve">d’autres veulent remplir de vif-argent les <lb/>trous par où elles ſortent, afin que par ſon poids il les contraigne <lb/>à prendre leur cours d’un autre côté. </s> <s xml:id="echoid-s4959" xml:space="preserve">Je crois que tous ces expe-<lb/>diens ne ſont bons que dans la ſpeculation, & </s> <s xml:id="echoid-s4960" xml:space="preserve">qu’ils ne réüſſiſſent <lb/>guére quand on veut les mettre en œuvre; </s> <s xml:id="echoid-s4961" xml:space="preserve">le meilleur parti eſt de <lb/>travailler promptement, & </s> <s xml:id="echoid-s4962" xml:space="preserve">pour ne point être inondé à un certain <lb/>point, il faut diriger les eaux par petites rigoles que l’on amenera à <lb/>un puits fait au-delà de la tranchée, d’où on les tirera par des ma-<lb/>chines à meſure qu’elles viendront, on leur laiſſera le cours libre <lb/>depuis leur origine juſqu’à ce puits, bordant les petites rigoles de <lb/>chaque côté avec des Briques pour former de petits canaux que <pb o="55" file="0235" n="242" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> l’on couvrira de pierres plattes, ainſi tout le fond de la tranchée ſera <lb/>mis à ſec: </s> <s xml:id="echoid-s4963" xml:space="preserve">cependant, pour prévenir que les ſources ne deviennent <lb/>par la ſuite nuiſibles aux fondemens, il faut pratiquer dans la Ma-<lb/>çonnerie des petits acqueducs, aſin de leur laiſſer un cours libre <lb/>du côté qui conviendra le mieux.</s> <s xml:id="echoid-s4964" xml:space="preserve"/> </p> <div xml:id="echoid-div272" type="float" level="3" n="6"> <note position="left" xlink:label="note-0234-02" xlink:href="note-0234-02a" xml:space="preserve">Maniere <lb/>de détour-<lb/>ner les <lb/>ſources.</note> </div> <p> <s xml:id="echoid-s4965" xml:space="preserve">Il arrive quelquefois qu’un terrain ſur lequel on veut fonder ne <lb/> <anchor type="note" xlink:label="note-0235-01a" xlink:href="note-0235-01"/> ſe trouve pas bon, & </s> <s xml:id="echoid-s4966" xml:space="preserve">que voulant aprofondir pour en chercher un <lb/>meilleur, on le rencontre encore plus mauvais; </s> <s xml:id="echoid-s4967" xml:space="preserve">en ce cas, il vaut <lb/>mieux ne s’enfoncer que le moins qu’on pourra, & </s> <s xml:id="echoid-s4968" xml:space="preserve">établir, ſur toute <lb/>la longueur des fondemens, un bon grillage aſſemblé avec des lon-<lb/>grines & </s> <s xml:id="echoid-s4969" xml:space="preserve">traverſines de 9 à 10 pouces de groſſeur, les vuides ou <lb/>celulles qu’elle forme ſe rempliſſent d’une bonne Maçonnerie de <lb/>Brique ou de Moîlon: </s> <s xml:id="echoid-s4970" xml:space="preserve">il y en a qui couvrent le tout d’un plancher <lb/>de gros madriers bien arrêtés ſur le grillage avec des chevilles de <lb/>fer enfoncées à tête perduë; </s> <s xml:id="echoid-s4971" xml:space="preserve">comme ce plancher paroît d’une dé-<lb/>penſe aſſés inutile, il ſuffit d’élever la maçonnerie immediatement <lb/>ſur le grillage, obſervant de faire le parement de bonne pierre de <lb/>taille juſqu’au rez-de-Chauſſée, & </s> <s xml:id="echoid-s4972" xml:space="preserve">même plus haut ſi l’ouvrage en <lb/>merite la peine. </s> <s xml:id="echoid-s4973" xml:space="preserve">Comme ces ſortes de fondations ne ſauroient avoir <lb/>de trop grands empattements, il eſt bon de faire le grillage d’un pied <lb/>& </s> <s xml:id="echoid-s4974" xml:space="preserve">demi ou deux plus large que n’euſſent été les fondemens, ſi on <lb/>les avoit établis dans un bon terrain; </s> <s xml:id="echoid-s4975" xml:space="preserve">& </s> <s xml:id="echoid-s4976" xml:space="preserve">afin de prévenir tout acci-<lb/>dent, il convient d’attacher ſur le bord du grillage du côté du foſſé, <lb/>un heurtoir de 8 ou 10 pouces au moins, qui, régnant ſur toute la <lb/>longueur des fondemens, empêchera que le pied du revêtement ne <lb/>puiſſe gliſſer, ſur-tout s’il étoit aſſis ſur un plancher, ce qui n’eſt pas <lb/>ſans exemple. </s> <s xml:id="echoid-s4977" xml:space="preserve">A Bergue St. </s> <s xml:id="echoid-s4978" xml:space="preserve">Vinoc, où le terrain eſt fort mauvais, il <lb/>eſt arrivé que le revêtement de la face d’une demi lune s’eſt déta-<lb/>ché, & </s> <s xml:id="echoid-s4979" xml:space="preserve">a été gliſſé tout d’une piece juſques dans le milieu du Foſſé: <lb/></s> <s xml:id="echoid-s4980" xml:space="preserve">cela s’eſt fait avec des circonſtances ſi ſingulieres, à ce que j’ai ap-<lb/>pris par les Ingenieurs qui étoient alors dans cette place, que cet <lb/>accident ſemble tenir quelque choſe du merveilleux.</s> <s xml:id="echoid-s4981" xml:space="preserve"/> </p> <div xml:id="echoid-div273" type="float" level="3" n="7"> <note position="right" xlink:label="note-0235-01" xlink:href="note-0235-01a" xml:space="preserve">Fonde-<lb/>mens avec <lb/>des grilla-<lb/>ges.</note> </div> <p> <s xml:id="echoid-s4982" xml:space="preserve">Cette façon de fonder n’eſt pas toûjours bonne dans toute ſorte <lb/> <anchor type="note" xlink:label="note-0235-02a" xlink:href="note-0235-02"/> de terrain, auſſi ne l’emploie-t-on guéres que dans de petites parties <lb/>de fondation, qui, n’étant point ſi bonnes que celles qui leur ſont <lb/>contiguës, ne laiſſent pas la liberté d’approfondir davantage ſans <lb/>de grands inconveniens: </s> <s xml:id="echoid-s4983" xml:space="preserve">cependant, on peut la rendre excellente <lb/>dans un terrain aquatique, ſi, après avoir poſé le grillage, on en-<lb/>fonce dans les celulles, des pilots de remplage ou de compreſſion ſur <lb/>toute l’étenduë des fondemens; </s> <s xml:id="echoid-s4984" xml:space="preserve">ces pilots doivent être plantés au <lb/>nombre d’un ou deux ſeulement dans chaque celulle diagonalement <pb o="56" file="0236" n="243" rhead="LA SCIENCE DES INGENIEURS,"/> opoſés, & </s> <s xml:id="echoid-s4985" xml:space="preserve">pour mieux aſſurer les fondemens, on pourra, ſi on le <lb/>juge néceſſaire, battre tout au tour du bord qui répond au Foſſé, <lb/>des pilots de bordage ou de gardes poſés près à près, & </s> <s xml:id="echoid-s4986" xml:space="preserve">le long de <lb/>ces pilots un fil de palplanche pour empêcher le courant des eaux, <lb/>s’il s’en trouve, de dégravoyer la Maçonnerie; </s> <s xml:id="echoid-s4987" xml:space="preserve">les vuides du gril-<lb/>lage, autour de la tête des pilots, doivent être remplis de gros quar-<lb/>tiers de pierre, & </s> <s xml:id="echoid-s4988" xml:space="preserve">après les avoir bien arraſſés on aſſeoira la Ma-<lb/>connerie élevée par aſſiſe reglée, afin qu’elle porte également par <lb/>tout.</s> <s xml:id="echoid-s4989" xml:space="preserve"/> </p> <div xml:id="echoid-div274" type="float" level="3" n="8"> <note position="right" xlink:label="note-0235-02" xlink:href="note-0235-02a" xml:space="preserve">Fonda-<lb/>tion fur <lb/>pilotis.</note> </div> <p> <s xml:id="echoid-s4990" xml:space="preserve">Quoique cette maniere de fonder ſoit bonne, je crois pourtant <lb/>qu’on ne feroit pas mal d’y changer quelque choſe pour la rendre <lb/> <anchor type="note" xlink:label="note-0236-01a" xlink:href="note-0236-01"/> encore plus ſolide. </s> <s xml:id="echoid-s4991" xml:space="preserve">C’eſt de commencer par enfoncer des rangées <lb/>de pilots tout le long des fondemens, par exemple pour un revê-<lb/>tement de rempart, après avoir tracé l’épaiſſeur que doivent avoir <lb/>les fondemens & </s> <s xml:id="echoid-s4992" xml:space="preserve">les contreforts, on enfoncera au refus du mou-<lb/>ton quatre rangées de pilots, une ſur l’allignement exterieur, l’au-<lb/>tre ſur l’interieur, & </s> <s xml:id="echoid-s4993" xml:space="preserve">deux dans le milieu; </s> <s xml:id="echoid-s4994" xml:space="preserve">enſorte que les pilots <lb/>ſoient ſeparés les uns des autres d’environ deux pieds. </s> <s xml:id="echoid-s4995" xml:space="preserve">On en plantera <lb/>deux ſous les angles des contre-forts, & </s> <s xml:id="echoid-s4996" xml:space="preserve">deux autres entre la queuë <lb/>& </s> <s xml:id="echoid-s4997" xml:space="preserve">la racine, comme on le remarque dans le premier profil, où les <lb/>têtes de ces pilots ſont ponctuées: </s> <s xml:id="echoid-s4998" xml:space="preserve">après les avoir récépés à niveau, on <lb/>appliquera deſſus des racinaux ou longrines, & </s> <s xml:id="echoid-s4999" xml:space="preserve">ſur ces longrines un <lb/>rang de traverſines pour former un grillage, dont chaque croiſée ſera <lb/>bien clouée & </s> <s xml:id="echoid-s5000" xml:space="preserve">arrêtée ſur la tête du pilot qui lui répond, & </s> <s xml:id="echoid-s5001" xml:space="preserve">ſelon <lb/>cette maniere le grillage ſera incomparablement plus ferme que dans <lb/>la pratique précédente: </s> <s xml:id="echoid-s5002" xml:space="preserve">après cela on enfoncera des pilots de rem-<lb/>plage, & </s> <s xml:id="echoid-s5003" xml:space="preserve">l’on pourra élever la Maçonnerie en toute ſeureté.</s> <s xml:id="echoid-s5004" xml:space="preserve"/> </p> <div xml:id="echoid-div275" type="float" level="3" n="9"> <note position="left" xlink:label="note-0236-01" xlink:href="note-0236-01a" xml:space="preserve">Autre ma-<lb/>niere de <lb/>fonder ſur <lb/>pilotis. <lb/><emph style="sc">Fig</emph>. 1. <lb/>& 2.</note> </div> <p> <s xml:id="echoid-s5005" xml:space="preserve">Quand on enfoncera des pilots, il faut avoir égard d’employer <lb/> <anchor type="note" xlink:label="note-0236-02a" xlink:href="note-0236-02"/> toûjours les plus longs & </s> <s xml:id="echoid-s5006" xml:space="preserve">les plus forts ſur les bords des fondemens, <lb/>puiſque ſi l’ouvrage a quelque danger à craindre par la ſuite, ceſera <lb/>plûtôt de ce côté-là qu’il manquera, que dans le milieu: </s> <s xml:id="echoid-s5007" xml:space="preserve">pour tra-<lb/>vailler avec précaution, il y a bien de petites attentions à faire ſur <lb/>la maniere de piloter; </s> <s xml:id="echoid-s5008" xml:space="preserve">&</s> <s xml:id="echoid-s5009" xml:space="preserve">, pour ne rien obmettre, voici comme <lb/>on pourra s’appercevoir de quelle longueur & </s> <s xml:id="echoid-s5010" xml:space="preserve">de quelle groſſeur on <lb/>doit employer les pilots ſelon le terrain où l’on aura à travailler.</s> <s xml:id="echoid-s5011" xml:space="preserve"/> </p> <div xml:id="echoid-div276" type="float" level="3" n="10"> <note position="left" xlink:label="note-0236-02" xlink:href="note-0236-02a" xml:space="preserve">Attention <lb/>for la ma-<lb/>niere de <lb/>niere de <lb/>piloter.</note> </div> <p> <s xml:id="echoid-s5012" xml:space="preserve">Il faut enfoncer un pilot juſqu’au refus du mouton, enſorte qu’on <lb/>puiſſe connoître à quelle profondeur le fond fait une aſſés grande <lb/>réſiſtance, pour s’opoſer fortement à la pointe; </s> <s xml:id="echoid-s5013" xml:space="preserve">ainſi ſachant de <lb/>combien il ſera enfoncé, on verra à peu-près la longueur qu’il fau-<lb/>dra donner; </s> <s xml:id="echoid-s5014" xml:space="preserve">je dis à peu-près, devant les faire un peu plus longs que <lb/>celui qui aura ſervi de ſonde, puiſqu’il ſe peut rencontrer des en- <pb o="57" file="0237" n="244" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> droits, où le terrain réſiſtant moins, ils pourront aller plus avant.</s> <s xml:id="echoid-s5015" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5016" xml:space="preserve">La longueur de pilots étant déterminée, il faut, pour y propor-<lb/>tionner leur groſſeur, qu’ils ayent de diamettre environ la 12 partie <lb/>de leur longueur, c’eſt-à-dire, que ceux qui auront 12 pieds, doi-<lb/>vent avoir environ 12 pouces de diamettre. </s> <s xml:id="echoid-s5017" xml:space="preserve">Mais cette regle ne doit <lb/>avoir lieu que pour les petits pilots depuis 6 pieds de longueur juſ-<lb/>qu’à 12; </s> <s xml:id="echoid-s5018" xml:space="preserve">car quand ils en ont 18 ou 20, il ſuffit de leur donner <lb/>13 ou 14 pouces de diamettre, autrement il faudroit employer des <lb/>arbres trop recherchés, ce qui augmenteroit conſidérablement la <lb/>dépenſe.</s> <s xml:id="echoid-s5019" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5020" xml:space="preserve">On ſait que pour enfoncer les pilots, on les fait en pointe de dia-<lb/>mant; </s> <s xml:id="echoid-s5021" xml:space="preserve">il faudra prendre garde de ne pas faire cette pointe trop <lb/>longue ni trop courte: </s> <s xml:id="echoid-s5022" xml:space="preserve">car ſi elle eſt trop courte elle ne s’enfoncera <lb/>pas aiſément, & </s> <s xml:id="echoid-s5023" xml:space="preserve">ſi elle eſt trop longue elle ſe trouvera affoiblie, de <lb/>maniere que pour peu qu’elle rencontre des parties qui lui réſiſtent, <lb/>elle s’émouſſera; </s> <s xml:id="echoid-s5024" xml:space="preserve">le mieux eſt de lui donner pour longueur une fois <lb/>& </s> <s xml:id="echoid-s5025" xml:space="preserve">demi ou deux fois au plus le diamettre du pilot. </s> <s xml:id="echoid-s5026" xml:space="preserve">Quand le terrain <lb/>dans lequel on les enfonce ne réſiſte pas beaucoup, on ſe contente <lb/>de brûler cette pointe pour la durcir, on en fait de même à la tête <lb/>pour empêcher que les coups de mouton ne l’éclatent; </s> <s xml:id="echoid-s5027" xml:space="preserve">mais ſi l’on <lb/>s’aperçoit qu’il ſe rencontre dans le terrain des pierres ou quel-<lb/>qu’autre choſe qui réſiſte fortement & </s> <s xml:id="echoid-s5028" xml:space="preserve">en émouſſe la pointe, on <lb/>l’arme d’un ſabot de fer, qu’on nomme auſſi lardoir, qui eſt retenu <lb/>par trois ou quatre branches clouées au pilot, l’on couronne auſſi <lb/>la tête du pilot d’une ceinture de fer que l’on nomme frette, pour la <lb/>tenir ſerrée contre les coups de mouton, & </s> <s xml:id="echoid-s5029" xml:space="preserve">pour lors l’on dit que les <lb/>pilots ſont frettés: </s> <s xml:id="echoid-s5030" xml:space="preserve">l’on proportionne comme j’en ai déja fait mention <lb/>la diſtance des pilots à la quantité qu’on croit avoir beſoin ſelon la <lb/>qualité du terrain; </s> <s xml:id="echoid-s5031" xml:space="preserve">mais au plus près qu’on puiſſe les mettre, il faut <lb/>au moins qu’ils ſoient ſeparés l’un de l’autre de l’intervalle d’un de <lb/>leur diamettre, afin qu’ils aïent aſſés de terre pour les entretenir.</s> <s xml:id="echoid-s5032" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5033" xml:space="preserve">Quand on veut garnir les devant des Fondemens par des pilots <lb/>de bordage, on y fait quelquefois des rainures qui ſe répondent dia-<lb/>métralement, dans leſquels on introduit des palplanches, on choiſit <lb/>les pilots les plus droits que l’on équarrit pour être employés plus <lb/>facilement, la largeur desrainures ſe proportionne à l’épaiſſeur des <lb/>palplanches; </s> <s xml:id="echoid-s5034" xml:space="preserve">mais on leur donne environ un pouce de plus pour <lb/>qu’elles puiſſent s’y introduire ſans difficulté; </s> <s xml:id="echoid-s5035" xml:space="preserve">ainſi quand les palplan-<lb/>ches ont deux pouces d’épaiſſeur, les rainures doivent en avoir trois <lb/>de largeur ſur deux de profondeur. </s> <s xml:id="echoid-s5036" xml:space="preserve">On obſervera auſſi que l’épaiſ-<lb/>ſeur des palplanches doit être reglée ſur leur longueur, par exem- <pb o="58" file="0238" n="245" rhead="LA SCIENCE DES INGENIEURS,"/> ple ſi elles ont 6 pieds, elles doivent avoir au moins 3 pouces, ſi <lb/>elles en ont 12 qui eſt ordinairement la plus grande longueur de <lb/>ces ſortes de bois, leur épaiſſeur ſera de quatre pouces.</s> <s xml:id="echoid-s5037" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5038" xml:space="preserve">Pour aſſembler les pilots avec les palplanches, on commence par <lb/>enfoncer deux pilots à plomb à une diſtance proportionnée à la lar-<lb/>geur des palplanches qui eſt le plus ſouvent de 12 à 15 pouces, <lb/>enſuite l’on enfonce une palplanche avec le mouton pour la faire <lb/>entrer à force entre les deux rainures, de façon qu’elle écarte tant <lb/>ſoit peu le pilot; </s> <s xml:id="echoid-s5039" xml:space="preserve">après cela on plante un autre pilot & </s> <s xml:id="echoid-s5040" xml:space="preserve">une pal-<lb/>planche, l’on continuë de la même maniere à battre alternative-<lb/>ment un pilot & </s> <s xml:id="echoid-s5041" xml:space="preserve">une palplanche. </s> <s xml:id="echoid-s5042" xml:space="preserve">Si le terrain réſiſte à la pointe des <lb/>palplanches, on les arme d’un ſabot de fer, & </s> <s xml:id="echoid-s5043" xml:space="preserve">on les frette ainſi <lb/>que les pilots.</s> <s xml:id="echoid-s5044" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5045" xml:space="preserve">Quoique de tout tems on ſe ſoit ſervi de pilots pour affermir un <lb/>mauvais terrain, il ſe rencontre neanmoins bien des occaſions où <lb/>il ſeroit dangereux de les employer; </s> <s xml:id="echoid-s5046" xml:space="preserve">par exemple, s’il étoit queſtion <lb/>d’un endroit aquatique où il y eut un grand nombre de ſources, il <lb/>ne faut pas croire que les pilots ſoient fort utiles pour y établir des <lb/>fondemens, mais au contraire, puiſqu’on a remarqué qu’en les en-<lb/>fonçant on éventoit les ſources, qui fourniſſoient de l’eau avec <lb/>tant d’abondance, que le terrain devenoit incomparablement plus <lb/>mauvais qu’il n’étoit auparavant: </s> <s xml:id="echoid-s5047" xml:space="preserve">& </s> <s xml:id="echoid-s5048" xml:space="preserve">ce qu’on trouvera aſſés extraor-<lb/>dinaire, c’eſt qu’ayant enfoncé des pilots à refus de mouton avec <lb/>autant de difficulté que ſi ç’avoit été dans un bon fonds, on étoit <lb/>étonné de voir que ces mêmes pilots étoient ſortis de terre le len-<lb/>demain, ou quelques heures après, parce que l’eau des ſources les <lb/>avoient repouſſés en faiſant effort pour ſortir, deſorte qu’il falut re-<lb/>noncer à s’en ſervir davantage, & </s> <s xml:id="echoid-s5049" xml:space="preserve">avoir recours à quelqu’autres <lb/>moyens beaucoup plus difficiles à executer, que ceux dont on au-<lb/>roit pû ſe ſervir d’abord, ſi au lieu de faire naître des difficultés, <lb/>on avoit cherché à les prévenir; </s> <s xml:id="echoid-s5050" xml:space="preserve">ce qui fait voir la neceſſité de rai-<lb/>ſonner meurement ſur la nature du travail que l’on a à faire, avant <lb/>de mettre la main à l’œuvre.</s> <s xml:id="echoid-s5051" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5052" xml:space="preserve">L’inconvenient que nous venons de remarquer arrive le plus <lb/>ſouvent dans les lieux où l’on rencontre du Sable boüillant qui eſt <lb/>une eſpece de terrain, qu’il importe fort de bien connoître: </s> <s xml:id="echoid-s5053" xml:space="preserve">car <lb/>comme l’eau qui boüillonne en ſortant de terre quand on paſſe <lb/>deſſus ne vient que de l’abondance des ſources qui s’y trouvent, <lb/>il faut bien prendre garde de ne pas l’éventer en voulant s’y apro-<lb/>fondir; </s> <s xml:id="echoid-s5054" xml:space="preserve">puiſque, plus on voudra s’obſtiner à y creuſer des fonde-<lb/>mens, moins l’on ſera en état de les executer: </s> <s xml:id="echoid-s5055" xml:space="preserve">le meilleur parti eſt <pb o="59" file="0239" n="246" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> de ne s’y enfoncer que le moins qu’on pourra, & </s> <s xml:id="echoid-s5056" xml:space="preserve">enſuite fonder <lb/>hardiment & </s> <s xml:id="echoid-s5057" xml:space="preserve">ſans autre ſujetion que celle que nous allons décrire.</s> <s xml:id="echoid-s5058" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5059" xml:space="preserve">Ayant tracé les allignemens & </s> <s xml:id="echoid-s5060" xml:space="preserve">fait les amas de matériaux neceſ-<lb/> <anchor type="note" xlink:label="note-0239-01a" xlink:href="note-0239-01"/> ſaires, on ne découvrira le terrain qu’à meſure qu’on fera la maçon-<lb/>nerie; </s> <s xml:id="echoid-s5061" xml:space="preserve">c’eſt-à-dire que ſi on peut faire par jour 6 toiſes courantes <lb/>de fondemens, on n’en découvrira pas davantage; </s> <s xml:id="echoid-s5062" xml:space="preserve">enſuite l’on aſ-<lb/>ſeoira avec le plus de diligence qu’il ſera poſſible une premiere aſſiſe <lb/>de gros libages plats, & </s> <s xml:id="echoid-s5063" xml:space="preserve">ſur celle-ci une autre bien arrangée à joints <lb/>recouverts en bain de bon mortier compoſé de terraſſe ou bien de <lb/>cendrée de Tournay, ſur cette ſeconde une toiſiéme, ainſi de ſuite <lb/>avec toute la promptitude poſſible, pour ne pas donner le tems <lb/>aux ſources d’innonder le travail, comme cela eſt aſſés ordinaire. </s> <s xml:id="echoid-s5064" xml:space="preserve">Il <lb/>arrive quelquefois que l’on voit flotter les premieres aſſiſes, & </s> <s xml:id="echoid-s5065" xml:space="preserve">que <lb/>la Maçonnerie ſemble ne pouvoir prendre conſiſtance; </s> <s xml:id="echoid-s5066" xml:space="preserve">mais il ne <lb/>faut pas s’en allarmer, aller ſon train, & </s> <s xml:id="echoid-s5067" xml:space="preserve">continuer toûjours s’il eſt <lb/>poſſible ſans interruption, & </s> <s xml:id="echoid-s5068" xml:space="preserve">quelque tems après la Maçonnerie <lb/>s’affermira comme ſi elle étoit établie ſur le roc: </s> <s xml:id="echoid-s5069" xml:space="preserve">c’eſt pourquoi l’on <lb/>peut élever le reſte ſans aprehender que l’ouvrage manque par le <lb/>pied, ni que les fondemens s’enfoncent guéres plus, après avoir <lb/>reçûs toute leur charge, qu’ils l’étoient au commencement; </s> <s xml:id="echoid-s5070" xml:space="preserve">il faut <lb/>ſeulement prendre garde ſur toute choſe de ne pas creuſer autour, <lb/>crainte d’y attirer l’eau de quelque ſource qui pourroit dégravoïer <lb/>la Maçonnerie, & </s> <s xml:id="echoid-s5071" xml:space="preserve">cauſer de grands dommages: </s> <s xml:id="echoid-s5072" xml:space="preserve">enfin, je dirai pour <lb/>juſtifier cette maniere de fonder, qu’on ne s’y prend pas autrement <lb/>à Douay, Lille, & </s> <s xml:id="echoid-s5073" xml:space="preserve">Bethune, quand il eſt queſtion de revêtir quel-<lb/>que ouvrage de Fortification dans un terrain comme celui-ci qui y <lb/>eſt aſſés ordinaire.</s> <s xml:id="echoid-s5074" xml:space="preserve"/> </p> <div xml:id="echoid-div277" type="float" level="3" n="11"> <note position="right" xlink:label="note-0239-01" xlink:href="note-0239-01a" xml:space="preserve">Fondation <lb/>ſur le ſable <lb/>boüillant.</note> </div> <p> <s xml:id="echoid-s5075" xml:space="preserve">A Arras & </s> <s xml:id="echoid-s5076" xml:space="preserve">à Bethune il y a encore un terrain tourbeux qu’il <lb/>eſt neceſſaire de connoître pour pouvoir y fonder hardiment: </s> <s xml:id="echoid-s5077" xml:space="preserve">ayant <lb/>cela de particulier, que dès qu’on veut creuſer un peu avant, il <lb/>en ſort une quantité d’eau prodigieuſe. </s> <s xml:id="echoid-s5078" xml:space="preserve">Après avoir tenté toutes <lb/>ſortes de voyes, on a trouvé que le plus court & </s> <s xml:id="echoid-s5079" xml:space="preserve">le plus ſûr parti <lb/>étoit d’y fonder hardiment avec de bons matériaux, ne s’enfonçant <lb/>que le moins qu’il eſt poſſible ſans employer ni grillage, ni pilots, <lb/>& </s> <s xml:id="echoid-s5080" xml:space="preserve">l’ouvrage ſe maintient ferme & </s> <s xml:id="echoid-s5081" xml:space="preserve">ſolide ſans courir aucun riſque.</s> <s xml:id="echoid-s5082" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5083" xml:space="preserve">Quand on rencontre de ſemblables terrains que l’on ne connoît <lb/>point parfaitement, il eſt bon de ne le ſonder qu’à une certaine diſ-<lb/>tance de l’endroit où on le veut travailler, parce que ſi l’on venoit <lb/>à creuſer trop avant, & </s> <s xml:id="echoid-s5084" xml:space="preserve">qu’il en ſortit une grande quantité d’eau, on <lb/>n’en ſera pas incommodé. </s> <s xml:id="echoid-s5085" xml:space="preserve">C’eſtici où je crois qu’on pourroit ſe ſer-<lb/>vir mieux que par-tout ailleurs de la Maçonnerie de pierrées dont <pb o="60" file="0240" n="247" rhead="LA SCIENCE DES INGENIEURS,"/> j’ai parlé ci-devant; </s> <s xml:id="echoid-s5086" xml:space="preserve">car comme elle eſt d’une prompte execution, <lb/>& </s> <s xml:id="echoid-s5087" xml:space="preserve">que toutes les parties ſe lient bien, on pourra en y mêlant de <lb/>la terraſſe de Hollande & </s> <s xml:id="echoid-s5088" xml:space="preserve">de la Cendrée de Tournay, faire un maſ-<lb/>ſif excellent, auquel donnant ſeulement deux pieds ou deux pieds <lb/>& </s> <s xml:id="echoid-s5089" xml:space="preserve">demi d’épaiſſeur, on formera une eſpece de banc ſur lequel on <lb/>pourra élever la Maçonnerie plus ſeurement que ſi l’on faiſoit un <lb/>grillage, & </s> <s xml:id="echoid-s5090" xml:space="preserve">même que ſi l’on avoit rencontré un ſable ou un gravier <lb/>bien ferme; </s> <s xml:id="echoid-s5091" xml:space="preserve">mais quand on prend ce parti il faut donner beaucoup <lb/>d’empattement à la Fondation, afin qu’embraſſant une plus grande <lb/>étenduë elle ſoit établie plus ſolidement.</s> <s xml:id="echoid-s5092" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5093" xml:space="preserve">Il y a encore une autre maniere de fonder par coffres, qui eſt <lb/>bien differente de celle dont j’ai parlé juſqu’ici; </s> <s xml:id="echoid-s5094" xml:space="preserve">on s’en ſert dans les <lb/>lieux où les terres n’ont point de cervelles & </s> <s xml:id="echoid-s5095" xml:space="preserve">où l’on a à ſe garentir des <lb/>ſources & </s> <s xml:id="echoid-s5096" xml:space="preserve">des éboulemens, on commence par creuſer à une pro-<lb/>fondeur convenable, un eſpace de quatre à cinq pieds de lon-<lb/>gueur & </s> <s xml:id="echoid-s5097" xml:space="preserve">dont la largeur eſt reglée ſur l’épaiſſeur que doivent avoir <lb/>les Fondemens: </s> <s xml:id="echoid-s5098" xml:space="preserve">on ſe ſert de madriers d’environ deux pouces d’é-<lb/>paiſſeur que l’on aplique de long des bords de la tranchée pour en <lb/>ſoûtenir les terres, les maintenant avec des étraiſillons qui traver-<lb/>ſent la fondation d’eſpace en eſpace, & </s> <s xml:id="echoid-s5099" xml:space="preserve">dont les bouts ſont apuyés <lb/>& </s> <s xml:id="echoid-s5100" xml:space="preserve">chaſſés à force contre les madriers opoſés; </s> <s xml:id="echoid-s5101" xml:space="preserve">aprèsavoir coffré ainſi <lb/>juſqu’à la profondeur où l’on peut atteindre ſans être inondé, on <lb/>remplit ce coffre d’une bonne Maçonnerie, quand les madriers ſe <lb/>trouvent apuyés par la Maçonnerie, on ôte les étreſillons à meſure. <lb/></s> <s xml:id="echoid-s5102" xml:space="preserve">Quand ce coffre eſt bien rempli, on en creuſe à côté un autre ſem-<lb/>blable, dont la longueur auſſi-bien que celle du premier dépend <lb/>de la facilité que l’on a d’embraſſer un eſpace plus ou moins grand <lb/>ſans être incommodé des ſources: </s> <s xml:id="echoid-s5103" xml:space="preserve">cependant, malgré les précau-<lb/>tions que l’on peut prendre, il arrive ſouvent que l’eau pouſſe tout <lb/>d’un coup ſans qu’on puiſſe l’empêcher; </s> <s xml:id="echoid-s5104" xml:space="preserve">mais il eſt facile de la ſur-<lb/>monter, car comme le terrain n’eſt guére découvert, un peu de <lb/>célérité vous met bien-tôt hors d’embaras, au lieu que ſi l’on s’y <lb/>prenoit autrement, on ſe trouveroit innondé de toute part d’un <lb/>nombre de ſources qui ſe déclareroient en même tems, qu’on ne <lb/>pourroit éteindre ſans des difficultés preſque inſurmontables.</s> <s xml:id="echoid-s5105" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5106" xml:space="preserve">Ayant fait trois ou quatre coffres de ſuite, & </s> <s xml:id="echoid-s5107" xml:space="preserve">la Maçonne-<lb/>rie des premiers étant bien affermie, on fait enſorte d’en retirer <lb/>les madriers pour s’en ſervir ailleurs, & </s> <s xml:id="echoid-s5108" xml:space="preserve">ſi on ne peut avoir ceux <lb/>qui ſont au fonds, ſans courir riſque de donner une iſſuë à une <lb/>ſource qu’on auroit ſurmontée, on prend le parti de les abandon-<lb/>ner.</s> <s xml:id="echoid-s5109" xml:space="preserve"/> </p> <pb o="61" file="0241" n="248" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> <p> <s xml:id="echoid-s5110" xml:space="preserve">Quand on veut élever quelque édifice dans l’eau, où l’on ne <lb/>peut faire d’épuiſement, (comme dans la mer) on a recours à une <lb/>maniere de fonder, qui paroîtra d’abord être peu ſolide, mais qui <lb/>eſt pourtant de durée, quand on y aporte toutes les precautions <lb/>neceſſaires; </s> <s xml:id="echoid-s5111" xml:space="preserve">ces ſortes de fondemens s’apellent à Pierre perduë, ou <lb/>Enrochement; </s> <s xml:id="echoid-s5112" xml:space="preserve">voici comme on les pratique.</s> <s xml:id="echoid-s5113" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5114" xml:space="preserve">On commence par remplir de pierres une grande quantité de <lb/> <anchor type="note" xlink:label="note-0241-01a" xlink:href="note-0241-01"/> batteaux, que l’on conduit près de l’endroit où on veut les emplo-<lb/>yer; </s> <s xml:id="echoid-s5115" xml:space="preserve">on profite du tems que la Marée eſt baſſe pour établir les al-<lb/>lignemens, & </s> <s xml:id="echoid-s5116" xml:space="preserve">égaliſer autant qu’il eſt poſſible le fond ſur lequel on <lb/>veut travailler, qui doit être non ſeulement de toute la capacité <lb/>que doit occuper l’édifice qu’on a en vûë, mais beaucoup au-delà, <lb/>afin d’avoir une Berme conſiderable, qui regnant au tour de la murail-<lb/>le, en aſſure davantage le pied: </s> <s xml:id="echoid-s5117" xml:space="preserve">tous les materiaux étant prêts d’être <lb/>employés, & </s> <s xml:id="echoid-s5118" xml:space="preserve">ayant choiſi le tems le plus convenable, on jette un lit de <lb/>pierre de Moilonage telle qu’elle ſort de la carriere, ou des cailloux; <lb/></s> <s xml:id="echoid-s5119" xml:space="preserve">ſur ce lit-ci on y en fait un autre de Chaux, mêlée de Pozzolane ou <lb/>de Terraſſe; </s> <s xml:id="echoid-s5120" xml:space="preserve">après cela on jette encore un autre lit de Moilon ou <lb/>de cailloux, qu’on couvre derechef de Chaux & </s> <s xml:id="echoid-s5121" xml:space="preserve">de Pozzolane, on <lb/>continuë alternativement un lit de pierre, & </s> <s xml:id="echoid-s5122" xml:space="preserve">un autre de Chaux & </s> <s xml:id="echoid-s5123" xml:space="preserve"><lb/>de Pozzolane, & </s> <s xml:id="echoid-s5124" xml:space="preserve">il ſe fait ſur le champ un maſtic qui rend cette <lb/>Maçonnerie dure & </s> <s xml:id="echoid-s5125" xml:space="preserve">ſolide, comme celle qui ſeroit faite avec plus <lb/>de précaution, par la proprieté admirable de la Pozzolane & </s> <s xml:id="echoid-s5126" xml:space="preserve">de la <lb/>Terraſſe; </s> <s xml:id="echoid-s5127" xml:space="preserve">car quoi qu’on ne puiſſe pas travailler de ſuite, à cauſe <lb/>des tourmentes de la mer, ou de la trop grande hauteur des eaux, <lb/>on peut continuer par repriſe ſans que cela porte aucun préjudice <lb/>à la bonté de l’ouvrage. </s> <s xml:id="echoid-s5128" xml:space="preserve">En jettant les pierres on a ſoin de répen-<lb/>dre les plus groſſes vers le bord, où l’on obſerve de faire un talud <lb/>qui ſoit au moins de deux fois ſa hauteur. </s> <s xml:id="echoid-s5129" xml:space="preserve">Après que l’enrochement <lb/>ſera élevé auſſi haut qu’on l’aura jugé neceſſaire, pour atteindre ſon <lb/>rez-de-Chauſſée, & </s> <s xml:id="echoid-s5130" xml:space="preserve">pour n’être point ſubmergé, il eſt bon de le <lb/>mettre à l’épreuve pendant pluſieurs années, des tourmentes de la <lb/>mer, & </s> <s xml:id="echoid-s5131" xml:space="preserve">pendant ce tems-là, il faut le ſurcharger de tous les mate-<lb/>riaux neceſſaires pour l’établiſſement de l’édifice qu’on veut élever, <lb/> <anchor type="note" xlink:label="note-0241-02a" xlink:href="note-0241-02"/> & </s> <s xml:id="echoid-s5132" xml:space="preserve">même au-delà s’il ſe peut, pour lui donner tout le poids qu’il <lb/>pourra jamais porter, afin qu’il s’affaiſſe dans tous les endroits où <lb/>le ſable peut être moins aſſuré. </s> <s xml:id="echoid-s5133" xml:space="preserve">Quand au bout d’un certain tems, <lb/>l’on voit qu’il ne lui eſt arrivé aucun accident conſiderable, on <lb/>établit deſſus de bons grillages couverts d’un plancher de gros ma-<lb/>driers, ſur lequel on aſſeoit l’édifice.</s> <s xml:id="echoid-s5134" xml:space="preserve"/> </p> <div xml:id="echoid-div278" type="float" level="3" n="12"> <note position="right" xlink:label="note-0241-01" xlink:href="note-0241-01a" xml:space="preserve">Fonde-<lb/>ment de <lb/>pierre per-<lb/>duë.</note> <note position="right" xlink:label="note-0241-02" xlink:href="note-0241-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 6. <lb/>& 7.</note> </div> <p> <s xml:id="echoid-s5135" xml:space="preserve">Quand on peut battre des pilots tout autour de l’eſpace que doit <pb o="62" file="0242" n="249" rhead="LA SCIENCE DES INGENIEURS,"/> occuper l’enrochement, on pourra y faire un bon empattement, <lb/>qui garantira le pied des degravoyemens qui pourroient arriver dans <lb/>la ſuite, & </s> <s xml:id="echoid-s5136" xml:space="preserve">par ce moyen l’ouvrage en ſera bien plus aſſuré, & </s> <s xml:id="echoid-s5137" xml:space="preserve">n’au-<lb/>ra en quelque façon rien à craindre; </s> <s xml:id="echoid-s5138" xml:space="preserve">l’on a auſſi ſoin de faire au <lb/>pied la muraille une risberme compoſée de facinage & </s> <s xml:id="echoid-s5139" xml:space="preserve">de gril-<lb/>lage, comme on le pratique aux jettées, pour empêcher que dans <lb/>un gros tems il ne ſurvienne des vagues qui pourroient ſaper le <lb/>mur: </s> <s xml:id="echoid-s5140" xml:space="preserve">malgré toutes les precautions qu’on peut prendre, il eſt toû-<lb/>jours bien dangereux de bâtir dans la mer; </s> <s xml:id="echoid-s5141" xml:space="preserve">cependant, nous avons <lb/>en France pluſieurs édifices de la nature de ceux dont je viens de <lb/>parler, qui ſubſiſtent depuis long-tems, ſans qu’il leur ſoit arrivé <lb/>aucun accident.</s> <s xml:id="echoid-s5142" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5143" xml:space="preserve">Je viens de ſupoſer un enrochement fait dans la mer, pour mon-<lb/>trer comme on peut ſurmonter les plus grands obſtacles qui ſe ren-<lb/>contrent en fondant; </s> <s xml:id="echoid-s5144" xml:space="preserve">mais il y a une infinité d’autres endroits où on <lb/>peut s’en ſervir utilement & </s> <s xml:id="echoid-s5145" xml:space="preserve">avec bien plus de ſuccés, comme dans <lb/>les rivieres, les lacs, les étangs, & </s> <s xml:id="echoid-s5146" xml:space="preserve">tous les lieux où on ne peut par-<lb/>venir à ètablir de fondemens à ſec. </s> <s xml:id="echoid-s5147" xml:space="preserve">Vitruve, dans le 12. </s> <s xml:id="echoid-s5148" xml:space="preserve">Chapitre <lb/>de ſon 5. </s> <s xml:id="echoid-s5149" xml:space="preserve">Livre, parlant des jettées qui ſe ſont aux ports de mer, <lb/>détaille aſſez bien la Maçonnerie à pierre perduë, ce qui joint à <lb/>d’autres recherches que j’ai faites ſur ce ſujet, j’en aurois pû par-<lb/>ler plus à fond que je ne viens de faire; </s> <s xml:id="echoid-s5150" xml:space="preserve">mais, comme ces ſortes <lb/>d’ouvrages apartiennent à l’Architecture Hidraulique, on trouvera <lb/>dans le ſecond volume de quoi ſe dedommager de ce qui manque <lb/>ici, je n’en aurois même fait aucune mention preſentement, ſi je <lb/>n’avois crû qu’il étoit à propos de donner dans ce Chapitre une <lb/>idée generale de toutes les differentes manieres de fonder.</s> <s xml:id="echoid-s5151" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5152" xml:space="preserve">Il y a encore un autre moyen de fonder dans les endroits que <lb/>nous venons de ſupoſer, qui eſt de ſe ſervir de Caiſſons dans leſ-<lb/>quels on maçonne à Chaux & </s> <s xml:id="echoid-s5153" xml:space="preserve">à Sable; </s> <s xml:id="echoid-s5154" xml:space="preserve">ces Caiſſons ne ſont autre <lb/>choſe qu’un aſſemblage de charpente bien calfaté: </s> <s xml:id="echoid-s5155" xml:space="preserve">on commence <lb/>par les conduire & </s> <s xml:id="echoid-s5156" xml:space="preserve">les arranger tous d’allignement à l’endroit où <lb/>l’on veut fonder, on les arrête par des cables qui paſſent dans des <lb/>anneaux de fer qui ſont attachez aux Caiſſons: </s> <s xml:id="echoid-s5157" xml:space="preserve">après les avoir bien <lb/>diſpoſés, on y met des Maçons qui les rempliſſent de bonne Ma-<lb/>çonnerie; </s> <s xml:id="echoid-s5158" xml:space="preserve">à meſure que l’ouvrage avance, le poids des pierres fait <lb/>enfoncer les Caiſſons dans l’eau juſqu’à ce qu’ils ayent atteint le <lb/>fond, c’eſt pourquoi l’on proportionne la hauteur des Caiſſons à <lb/>la profondeur de l’eau qu’il y a dans le lieu où l’on travaille, & </s> <s xml:id="echoid-s5159" xml:space="preserve"><lb/>l’on obſerve même de les faire deux ou trois pieds plus hauts, afin <lb/>que les ouvriers n’en ſoient point incommodés; </s> <s xml:id="echoid-s5160" xml:space="preserve">mais quand la pro- <pb o="63" file="0243" n="250" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> fondeur de l’eau eſt conſiderable, & </s> <s xml:id="echoid-s5161" xml:space="preserve">qu’on ne peut pas atteindre <lb/>le fond ſans donner aux Caiſſons une hauteur extraordinaire, on <lb/>prend le parti d’en augmenter la hauteur avec des hauſſes, à meſure <lb/>qu’il approche du fond.</s> <s xml:id="echoid-s5162" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5163" xml:space="preserve">Quelquefois l’on établit les Caiſſons ſur un enrochement quand <lb/> <anchor type="note" xlink:label="note-0243-01a" xlink:href="note-0243-01"/> le lit ſur lequel on veut fonder n’eſt pas uni, ſoit à cauſe des trous, <lb/>ou des petits bancs de ſable, ou bien quand les eaux ſont par trop <lb/>hautes.</s> <s xml:id="echoid-s5164" xml:space="preserve"/> </p> <div xml:id="echoid-div279" type="float" level="3" n="13"> <note position="right" xlink:label="note-0243-01" xlink:href="note-0243-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 4. <lb/>& 5.</note> </div> <p> <s xml:id="echoid-s5165" xml:space="preserve">Si l’on vouloit raporter toutes les differentes manieres de fonder <lb/>ſelon les occaſions qui ſe peuvent preſenter, je ne finirois jamais: <lb/></s> <s xml:id="echoid-s5166" xml:space="preserve">c’eſt pourquoi je me tiendrai à l’idée que je viens d’en donner, me <lb/>reſervant pourtant d’entrer encore dans quelque détail ſur ce ſujet <lb/>quand la choſe en meritera la peine, comme par exemple, pour les <lb/>fondemens des Ponts de Maçonnerie, des Ecluſes, & </s> <s xml:id="echoid-s5167" xml:space="preserve">autres ouvra-<lb/>ges, qui demandent beaucoup d’attention, pour les établir ſolide-<lb/>ment, & </s> <s xml:id="echoid-s5168" xml:space="preserve">que j’ai traité à fond dans le ſecond volume; </s> <s xml:id="echoid-s5169" xml:space="preserve">cependant le <lb/>peu que je viens d’inſinuer pourra donner aſſés de connoiſſance à <lb/>ceux qui ont deſſein de s’appliquer à l’Architecture, pour que d’eux <lb/>mêmes ayant un peu de pratique & </s> <s xml:id="echoid-s5170" xml:space="preserve">d’intelligence, ils puiſſent faire <lb/>le choix qui conviendra le mieux, entre les differens moyens que <lb/>je propoſe.</s> <s xml:id="echoid-s5171" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5172" xml:space="preserve">Je n’ai point parlé juſqu’ici de la profondeur qu’il falloit donner <lb/>aux fondemens, parce qu’il eſt aſſés difficile de la determiner, de-<lb/>pendant en quelque ſorte de la nature du terrain où l’on travaille; <lb/></s> <s xml:id="echoid-s5173" xml:space="preserve">mais je ferai au moins remarquer, que la plûpart des Architectes <lb/>font des depenſes fort inutiles, leur donnant une grande profon-<lb/>deur, qui ne contribuë en rien à la ſolidité de l’édifice, car de deux <lb/>choſes l’une, le terrain ſera bon, ou il ſera mauvais; </s> <s xml:id="echoid-s5174" xml:space="preserve">s’il eſt bon, <lb/>on peut bâtir en toute aſſeurance; </s> <s xml:id="echoid-s5175" xml:space="preserve">s’il ne l’eſt pas, on en ſera quit-<lb/>te en faiſant un bon plancher de madriers ou de grillage, ſans creu-<lb/>ſer plus avant pour chercher un autre fond, qu’on ne trouveroit <lb/>peut-être pas meilleur, & </s> <s xml:id="echoid-s5176" xml:space="preserve">ſi le terrain eſt mouvant ou marecageux, <lb/>il y a encore moins de raiſon d’aprofondir, puis qu’on ſera toû-<lb/>jours contraint de piloter; </s> <s xml:id="echoid-s5177" xml:space="preserve">or, dans tous ces cas, la profondeur des <lb/>fondemens ne fera rien pour la ſolidité des murs qu’on veut élever, <lb/>le tout eſt de les établir ſur une baſe ferme & </s> <s xml:id="echoid-s5178" xml:space="preserve">bien aſſurée, ſi on ne la <lb/>rencontre point telle qu’on peut la ſouhaiter, il faut avoir recours <lb/>aux expediens que nous venons de dire; </s> <s xml:id="echoid-s5179" xml:space="preserve">on n’en a pas uſé autre-<lb/>ment pour touts les grands édifices qui ſubſiſtent depuis tant de ſié-<lb/>cles: </s> <s xml:id="echoid-s5180" xml:space="preserve">les fondemens de l’Egliſe de Notre-Dame de Paris, qui eſt un <lb/>Vaiſſeau des plus conſiderables, quoi que bâti dans un fort mau- <pb o="64" file="0244" n="251" rhead="LA SCIENCE DES INGENIEURS,"/> vais terrain, n’ont preſque pas de profondeur; </s> <s xml:id="echoid-s5181" xml:space="preserve">tous ceux des Ponts <lb/>de la même Ville n’en ont que fort peu non plus, & </s> <s xml:id="echoid-s5182" xml:space="preserve">ne ſe ſoûtien-<lb/>nent pas moins, tandis qu’on voit donner à de ſimples maiſons, des <lb/>fondemens de ſept à huit pieds de profondeur, ſans faire attention <lb/>que leur quatre faces, formant un paralellepipede, doivent ſe ſoû-<lb/>tenir par leur propre poids; </s> <s xml:id="echoid-s5183" xml:space="preserve">que ſi on en voit quelque fois man-<lb/>quer par le pied, il ne faut pas penſer que cela vienne de ce que <lb/>leurs fondemens n’ont pas eu aſſés de profondeur; </s> <s xml:id="echoid-s5184" xml:space="preserve">mais parce qu’on <lb/>ne les a bâtis que peu à peu, c’eſt-à-dire qu’il y aura eu des repri-<lb/>ſes d’ouvrages, où la vieille Maçonnerie ne ſe ſera pas liée avec la <lb/>nouvelle, de-là il arrive que ſi un mur eſt affermi parce qu’il aura <lb/>été bâti le premier, l’autre ne l’eſt pas pour avoir été fait plus tard, <lb/>& </s> <s xml:id="echoid-s5185" xml:space="preserve">tous ces murs venant à être chargés enſemble, le fardeau étant <lb/>inegallement porté, la partie la plus foible flechit, tandis que l’au-<lb/>tre reſiſte. </s> <s xml:id="echoid-s5186" xml:space="preserve">Ajoutons à cela qu’un côté peut avoir été travaillé avec <lb/>de bons materiaux, & </s> <s xml:id="echoid-s5187" xml:space="preserve">l’autre fait avec moins de précautions: </s> <s xml:id="echoid-s5188" xml:space="preserve">ainſi <lb/>ce qu’on attribuë au défaut des fondemens, provient preſque toû-<lb/>jours de la mauvaiſe façon.</s> <s xml:id="echoid-s5189" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5190" xml:space="preserve">Mais ſi dans un bâtiment on commence par creuſer les tranchées <lb/>de tous les murs, & </s> <s xml:id="echoid-s5191" xml:space="preserve">qu’après les avoir miſes de niveau, on y établit une <lb/>bonne Maçonnerie, toûjours conduite à même hauteur, & </s> <s xml:id="echoid-s5192" xml:space="preserve">dont tou-<lb/>tes les parties differentes ſoient bien liées, & </s> <s xml:id="echoid-s5193" xml:space="preserve">qu’enſuite on éleve deſ-<lb/>ſus dans le même tems les pignons & </s> <s xml:id="echoid-s5194" xml:space="preserve">les refands, on peut s’aſſurer que <lb/>quand les fondemens n’auroient que deux ou trois pieds au plus <lb/>de profondeur, l’ouvrage ne court aucun danger, au lieu que s’il <lb/>n’eſt conduit que par parties, & </s> <s xml:id="echoid-s5195" xml:space="preserve">qu’on tombe dans les défauts que <lb/>je viens de remarquer, quand ces fondemens auroient 15. </s> <s xml:id="echoid-s5196" xml:space="preserve">à 20. <lb/></s> <s xml:id="echoid-s5197" xml:space="preserve">pieds, le bâtiment ne ſeroit pas moins ſujet à tous les inconviens <lb/>que la mauvaiſe façon peut cauſer.</s> <s xml:id="echoid-s5198" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5199" xml:space="preserve">S’il étoit queſtion de quelque gros mur d’enceinte ou de quay, <lb/>il faudra non ſeulement avoir toutes les attentions dont on vient <lb/>de parler, mais être plus attentif à leur faire des empattemens lar-<lb/>ges & </s> <s xml:id="echoid-s5200" xml:space="preserve">bien aſſis, qu’à les faire profonds, & </s> <s xml:id="echoid-s5201" xml:space="preserve">cette largeur qui exce-<lb/>dera celle du mur, doit particulierement regner du côté oppoſé où <lb/>le mur aura quelque effort conſiderable à ſoûtenir, ſoit de la part <lb/>de la pouſſée des terres, ou de celle d’une voute; </s> <s xml:id="echoid-s5202" xml:space="preserve">on en doit ſen-<lb/>tir la neceſſité, par ce qui a été dit dans le premier livre; </s> <s xml:id="echoid-s5203" xml:space="preserve">on eſt <lb/>pourtant quelquefois obligé de donner de la profondeur aux fon-<lb/>demens quoique le terrain ſoit bon, ce qui ſe fait lors qu’on tra-<lb/>vaille ſur le bord d’une riviere, afin de ſe mettre au-deſſus de ſon <lb/>lit, crainte que les eaux ne viennent par la ſuite à degravoyer le <pb file="0245" n="252"/> <pb file="0245a" n="253"/> <anchor type="figure" xlink:label="fig-0245a-01a" xlink:href="fig-0245a-01"/> <pb file="0246" n="254"/> <pb o="65" file="0247" n="255" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> terrain, & </s> <s xml:id="echoid-s5204" xml:space="preserve">à miner les fondemens, ce qui eſt fort à craindre quand <lb/>on eſt dans le voiſinage d’une Ecluſe, où il y a une grande chute <lb/>d’eau.</s> <s xml:id="echoid-s5205" xml:space="preserve"/> </p> <div xml:id="echoid-div280" type="float" level="3" n="14"> <figure xlink:label="fig-0245a-01" xlink:href="fig-0245a-01a"> <image file="0245a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0245a-01"/> </figure> </div> <p> <s xml:id="echoid-s5206" xml:space="preserve">Puiſque nous en ſommes ſur l’épaiſſeur des fondemens, il eſt à <lb/>propos d’en dire quelque choſe, paroiſſant y avoir encore ici des <lb/>difficultez qui ont beſoin d’être examinées.</s> <s xml:id="echoid-s5207" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5208" xml:space="preserve">Les fondemens d’un mur étant la baſe ſur laquelle il eſt établi, <lb/>il ſemble que la largeur de cette baſe doit être proportionnée, non <lb/>ſeulement à l’épaiſſeur du mur, mais plus encore à ſa hauteur, & </s> <s xml:id="echoid-s5209" xml:space="preserve"><lb/>qu’on doit ſuivre une certaine regle pour déterminer la largeur des <lb/>retraites du rez-de-Chauſſée; </s> <s xml:id="echoid-s5210" xml:space="preserve">mais c’eſt ce que les Architectes <lb/>n’ont point fait que je ſache: </s> <s xml:id="echoid-s5211" xml:space="preserve">il eſt bien vrai qu’ils ont parlé de l’é-<lb/>paiſſeur qu’il falloit donner aux fondemens, par raport à celle du <lb/>mur qu’ils devoient porter; </s> <s xml:id="echoid-s5212" xml:space="preserve">mais, ils n’ont pas eu égard à la hauteur <lb/>de ces murs. </s> <s xml:id="echoid-s5213" xml:space="preserve">Par exemple, Scamozzi veut que l’on donne pour <lb/>retraite de chaque côté, la huitiéme partie de l’épaiſſeur du mur, <lb/>c’eſt-à-dire, que s’il a quatre pieds d’épaiſſeur, il faudra en donner <lb/>cinq aux fondemens. </s> <s xml:id="echoid-s5214" xml:space="preserve">Philbert de Lorme fait ſes fondemens plus <lb/>épais, donnant pour retraite de chaque côté, un quart de l’épaiſ-<lb/>ſeur du mur; </s> <s xml:id="echoid-s5215" xml:space="preserve">ainſi, à un mur de quatre pieds d’épaiſſeur, il en don-<lb/>ne ſix aux fondemens. </s> <s xml:id="echoid-s5216" xml:space="preserve">Palladio les fait encore plus épais, voulant <lb/>qu’ils ayent le double de l’épaiſſeur du mur: </s> <s xml:id="echoid-s5217" xml:space="preserve">& </s> <s xml:id="echoid-s5218" xml:space="preserve">ce qu’il y a de ſur-<lb/>prenant, comme je le viens de dire, c’eſt que ni les uns ni les autres <lb/>ne font aucune mention de la hauteur des murs; </s> <s xml:id="echoid-s5219" xml:space="preserve">cependant il n’y a <lb/>pas de raiſon de donner autant d’épaiſſeur aux fondemens d’un mur <lb/>de clôture d’une hauteur mediocre qui ne porte rien, qu’à ceux <lb/>des pieds droits d’une voute fort élevée & </s> <s xml:id="echoid-s5220" xml:space="preserve">maſſive, ou d’un autre <lb/>mur qui doit porter pluſieurs grands planchers, chargés de fardeaux <lb/>conſiderables, comme aux Arſenaux & </s> <s xml:id="echoid-s5221" xml:space="preserve">aux Magaſins pour les <lb/>vivres; </s> <s xml:id="echoid-s5222" xml:space="preserve">car, il n’y a point d’édifice dont les murs n’ayent quelque <lb/>pouſſée à ſoûtenir, & </s> <s xml:id="echoid-s5223" xml:space="preserve">c’eſt ce qui fait qu’ils ſurplombent plûtôt en <lb/>dehors qu’en dedans: </s> <s xml:id="echoid-s5224" xml:space="preserve">d’ailleurs, quand un mur eſt fort élevé, & </s> <s xml:id="echoid-s5225" xml:space="preserve"><lb/>qu’il n’a qu’une épaiſſeur mediocre, ſi l’empattement n’eſt pas pro-<lb/>portionné à l’élevation, pour peu que le mur vienne à s’incliner <lb/>la longueur du bras de lévier a un ſi grand avantage ſur la reſiſtance <lb/>que les fondemens peuvent rencontrer de la part du terrain, qu’il <lb/>faut que ce terrain ſoit d’une ſolidité extrême, pour ne pas flechir: <lb/></s> <s xml:id="echoid-s5226" xml:space="preserve">car il eſt bon de faire attention ici, qu’un mur & </s> <s xml:id="echoid-s5227" xml:space="preserve">ſes fondemens <lb/>doivent être conſidéres comme ne faiſant qu’un ſeul corps, quoi-<lb/>que j’aye ſupoſé le contraire dans le premier & </s> <s xml:id="echoid-s5228" xml:space="preserve">le ſecond Livre: </s> <s xml:id="echoid-s5229" xml:space="preserve"><lb/>par conſequent, ſi le point d’apui, au lieu de repondre au rez-de- <pb o="66" file="0248" n="256" rhead="LA SCIENCE DES INGENIEURS,"/> Chauſſée, ſe trouve ſur le bord de la premiere aſſiſe des fondemens, <lb/>il faut neceſſairement, pour qu’un mur fort élevé ſoit auſſi bien aſſis <lb/>qu’un autre plus bas, qu’il y ait une proportion entre l’épaiſſeur de <lb/>leur fondement; </s> <s xml:id="echoid-s5230" xml:space="preserve">& </s> <s xml:id="echoid-s5231" xml:space="preserve">cette proportion eſt ſur-tout eſſentielle, quand <lb/>le mur qui a le plus d’élevation n’a qu’une mediocre épaiſſeur, <lb/>comme ſont par exemple la plûpart des pignons. </s> <s xml:id="echoid-s5232" xml:space="preserve">Or pour ſavoir à <lb/>quoi nous en tenir, ſans adopter aucune des regles des Architec-<lb/>tes que je viens de citer, nous ſupoſerons qu’un mur de 20. </s> <s xml:id="echoid-s5233" xml:space="preserve">pieds <lb/>de hauteur ſera parfaitement aſſuré ſur ſa baſe, quand on donnera <lb/>à ſes fondemens quatre pouces d’épaiſſeur de plus de chaque côté <lb/>que n’en à le mur, c’eſt-à-dire, que s’il avoit deux pieds d’épaiſſeur, <lb/>ſes fondemens auroient deux pieds huit pouces: </s> <s xml:id="echoid-s5234" xml:space="preserve">preſentement, vou-<lb/>lant ſavoir quelle épaiſſeur il faut donner aux fondemens d’un mur <lb/>qui auroit 50. </s> <s xml:id="echoid-s5235" xml:space="preserve">pieds de hauteur, je fais abſtraction pour un mo-<lb/>ment de l’épaiſſeur de ce mur, pour n’avoir égard qu’aux retraites <lb/>qu’on doit donner de chaque côté pour faire cette proportion: </s> <s xml:id="echoid-s5236" xml:space="preserve">ſi à <lb/>un mur de 20. </s> <s xml:id="echoid-s5237" xml:space="preserve">pieds de hauteur il faut donner 4 pouces de re-<lb/>traite de chaque côté, combien en faudra-t’il donner à un mur de <lb/>50. </s> <s xml:id="echoid-s5238" xml:space="preserve">pieds; </s> <s xml:id="echoid-s5239" xml:space="preserve">faiſant la regle on trouvera que chaque retraite doit être <lb/>de dix pouces, par conſequent ſi le mur avoit trois pieds d’épaiſ-<lb/>ſeur, il faudroit donner à ſes fondemens quatre pieds 8. </s> <s xml:id="echoid-s5240" xml:space="preserve">pouces, <lb/>de même s’il étoit queſtion d’un mur de 80. </s> <s xml:id="echoid-s5241" xml:space="preserve">pieds, on ſuivra toû-<lb/>jours la même proportion, en prenant 20. </s> <s xml:id="echoid-s5242" xml:space="preserve">pieds pour premier ter-<lb/>me, & </s> <s xml:id="echoid-s5243" xml:space="preserve">quatre pouces pour le ſecond.</s> <s xml:id="echoid-s5244" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5245" xml:space="preserve">Quand on voudra élever des murs qui ont quelque pouſſée à <lb/>ſoûtenir, il n’eſt pas neceſſaire de les aſſeoir ſur le milieu des fon-<lb/>demens, il vaut beaucoup mieux, après en avoir trouvé l’épaiſſeur, <lb/>donner plus de largeur à la retraite qui répond au point d’apui, qu’à <lb/>l’autre: </s> <s xml:id="echoid-s5246" xml:space="preserve">je voudrois même la faire double; </s> <s xml:id="echoid-s5247" xml:space="preserve">c’eſt-à-dire, qu’ayant <lb/>trouvé par la regle precedente, qu’il faut donner dix pouces de re-<lb/>traite de chaque côté aux fondemens d’un mur de 50. </s> <s xml:id="echoid-s5248" xml:space="preserve">pieds de <lb/>hauteur, & </s> <s xml:id="echoid-s5249" xml:space="preserve">qui eſt chargé d’un grand comble, & </s> <s xml:id="echoid-s5250" xml:space="preserve">de pluſieurs plan-<lb/>chers, qu’ayant ajoûté enſemble les deux retraites qui font 20. </s> <s xml:id="echoid-s5251" xml:space="preserve">pou-<lb/>ces, on en donnera 13 ou 14 à la retraite du dehors, & </s> <s xml:id="echoid-s5252" xml:space="preserve">ſix ou 7 à cel-<lb/>le du dedans, ainſi le bras de lévier qui répond à la puiſſance re-<lb/>ſiſtante, ſe trouvant allongé par raport au centre de gravité de la <lb/>muraille, le tout ſera beaucoup plus aſſuré, & </s> <s xml:id="echoid-s5253" xml:space="preserve">il n’arrivera pas les <lb/>defauts que l’on remarque dans la plûpart des bâtimens.</s> <s xml:id="echoid-s5254" xml:space="preserve"/> </p> <pb o="67" file="0249" n="257" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> </div> <div xml:id="echoid-div282" type="section" level="2" n="86"> <head xml:id="echoid-head224" xml:space="preserve">CHAPITRE DIXIE’ME. <lb/>Où l’on enſeigne comme l’on doit employer les Matériaux qui <lb/>compoſent la Maçonnerie.</head> <p> <s xml:id="echoid-s5255" xml:space="preserve">LA meilleure de toutes les Maçonneries eſt ſans difficulté celle <lb/>qui eſt faite de pierres de taille; </s> <s xml:id="echoid-s5256" xml:space="preserve">mais, comme cette pierre eſt <lb/>aſſés rare, il n’eſt pas ordinaire de faire des Bâtimens qui en ſoient <lb/>tout compoſés: </s> <s xml:id="echoid-s5257" xml:space="preserve">l’on ſe contente ſeulement de les employer pour <lb/>les ſoûbaſſemens des gros murs, aux encoigneures des Edifices, & </s> <s xml:id="echoid-s5258" xml:space="preserve"><lb/>aux angles des revêtemens des ouvrages des Fortifications: </s> <s xml:id="echoid-s5259" xml:space="preserve">pour la <lb/>mettre en œuvre, l’on en prépare de deux eſpeces; </s> <s xml:id="echoid-s5260" xml:space="preserve">la premiere, que <lb/>l’on nomme carreau ou pannereſſe, eſt celle dont la largeur excede <lb/>la longueur; </s> <s xml:id="echoid-s5261" xml:space="preserve">la ſeconde, que l’on nomme boutiſſe, eſt celle dont la <lb/>longueur excede la largeur; </s> <s xml:id="echoid-s5262" xml:space="preserve">les pannereſſes font parement de toute <lb/>leur largeur, & </s> <s xml:id="echoid-s5263" xml:space="preserve">les boutiſſes de leur tête ſeulement, leur queuë <lb/>faiſant partie de l’épaiſſeur du mur: </s> <s xml:id="echoid-s5264" xml:space="preserve">c’eſt ainſi qu’on les diſtribuë <lb/>dans chaque aſſiſe, obſervant de placer une boutiſſe, enſuite une <lb/>pannereſſe, ſucceſſivement une boutiſſe & </s> <s xml:id="echoid-s5265" xml:space="preserve">une pannereſſe poſées <lb/>plain ſur joint; </s> <s xml:id="echoid-s5266" xml:space="preserve">c’eſt-a-dire que les joints perpendiculaires de la ſe-<lb/>conde aſſiſe répondent au milieu des pierres de la premiere, ainſi <lb/>des autres qui ſont au-deſſus: </s> <s xml:id="echoid-s5267" xml:space="preserve">pour cela l’on fait les aſſiſes bien re-<lb/>glées, enſorte que les carreaux & </s> <s xml:id="echoid-s5268" xml:space="preserve">les boutiſſes ayent la même hau-<lb/>teur, afin que les joints horiſontaux qui regnent ſur toute la lon-<lb/>gueur du mur, faſſent des lignes paralelles & </s> <s xml:id="echoid-s5269" xml:space="preserve">de niveau: </s> <s xml:id="echoid-s5270" xml:space="preserve">à meſure <lb/>que l’on poſe une de ces aſſiſes, on garnit le reſte de l’épaiſſeur du <lb/>mur de briques ou de moîlon maçonné avec de bon mortier, & </s> <s xml:id="echoid-s5271" xml:space="preserve"><lb/>quand il n’eſt que d’une médiocre épaiſſeur on tâche d’avoir des <lb/>boutiſſes aſſés longues pour quelles puiſſent le traverſer & </s> <s xml:id="echoid-s5272" xml:space="preserve">faire pa-<lb/>rement des deux côtés, ce qui rend la Maçonnerie beaucoup plus <lb/>ſolide par la liaiſon qui ſe fait du parement avec le reſte du mur; <lb/></s> <s xml:id="echoid-s5273" xml:space="preserve">& </s> <s xml:id="echoid-s5274" xml:space="preserve">quand cela ſe pratique ainſi, les boutiſſes qui font parement des <lb/>deux côtés ſe nomment pierres de parpain ou parpaigne.</s> <s xml:id="echoid-s5275" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5276" xml:space="preserve">Quand on conſtruit quelque Edifice militaire dont les murs doi-<lb/>vent être d’une épaiſſeur conſidérable comme de 5 ou 6 pieds, on <lb/>employe de la graiſſerie au parement juſqu’à une certaine hauteur, <lb/>de la brique pour le parement interieur, & </s> <s xml:id="echoid-s5277" xml:space="preserve">le reſte de l’épaiſſeur ſe <lb/>fait de moîlon; </s> <s xml:id="echoid-s5278" xml:space="preserve">or, pour que le tout ſoit en bonne liaiſon, on em- <pb o="68" file="0250" n="258" rhead="LA SCIENCE DES INGENIEURS,"/> ploye la graiſſerie comme on vient de le dire; </s> <s xml:id="echoid-s5279" xml:space="preserve">à l’égard de la brique, <lb/>on commence par poſer une premiere aſſiſe de deux briques & </s> <s xml:id="echoid-s5280" xml:space="preserve">demi <lb/>d’épaiſſeur, une ſeconde de deux briques, & </s> <s xml:id="echoid-s5281" xml:space="preserve">une troiſiéme d’une & </s> <s xml:id="echoid-s5282" xml:space="preserve"><lb/>demi, chaque aſſiſe bien arraſée avec du moîlon, après quoi on <lb/>recommence tout de nouveau une aſſiſe de deux briques & </s> <s xml:id="echoid-s5283" xml:space="preserve">demi, <lb/>une ſeconde de deux briques, & </s> <s xml:id="echoid-s5284" xml:space="preserve">une troiſiéme d’une brique & </s> <s xml:id="echoid-s5285" xml:space="preserve">demi <lb/>toûjours bien liées & </s> <s xml:id="echoid-s5286" xml:space="preserve">arraſées avec le moîlon & </s> <s xml:id="echoid-s5287" xml:space="preserve">la graiſſerie. </s> <s xml:id="echoid-s5288" xml:space="preserve">Quand <lb/>on eſt parvenu à la derniere aſſiſe de graiſſerie & </s> <s xml:id="echoid-s5289" xml:space="preserve">qu’on veut faire <lb/>de brique le reſte de la hauteur du parement, on la poſe par aſſiſe <lb/>reglée comme on vient de le voir pour l’interieur, & </s> <s xml:id="echoid-s5290" xml:space="preserve">afin de rendre <lb/>la liaiſon plus parfaite, on peut de trois en trois aſſiſes faire une <lb/>chaîne de deux briques d’épaiſſeur ſur toute l’étenduë de l’ouvrage <lb/>poſées plain ſur joint.</s> <s xml:id="echoid-s5291" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5292" xml:space="preserve">Les ſoûbaſſemens d’un mur étant faits, ſi on éleve le reſte du pa-<lb/>rement avec du moîlon, on a ſoin de le bien ébouſiner & </s> <s xml:id="echoid-s5293" xml:space="preserve">de le <lb/>tailler juſqu’au vif, l’on ſe ſert encore de boutiſſes & </s> <s xml:id="echoid-s5294" xml:space="preserve">de pannereſſes, <lb/>en obſervant toûjours de ne les poſer que plain ſur joint, car ce ſe-<lb/>roit un deffaut groſſier de voir deux ou pluſieurs joints perpendi-<lb/>culaires ſur un même allignement, parce que le mur n’en ſeroit pas <lb/>ſi ſolide, & </s> <s xml:id="echoid-s5295" xml:space="preserve">choqueroit le coup d’œil. </s> <s xml:id="echoid-s5296" xml:space="preserve">Dans les ouvrages que l’on <lb/>veut faire proprement, on a égard, non-ſeulement de donner la mê-<lb/>me hauteur à toutes les pierres qui doivent compoſer les aſſiſes; <lb/></s> <s xml:id="echoid-s5297" xml:space="preserve">mais encore de les tailler de façon que la largeur des pannereſſes <lb/>ſoit double de celles de la tête des boutiſſes, afin d’obſerver une <lb/>bonne liaiſon & </s> <s xml:id="echoid-s5298" xml:space="preserve">un certain ordre de ſimétrie qui fait un fort bel <lb/>effet.</s> <s xml:id="echoid-s5299" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5300" xml:space="preserve">Les Anciens étoient extrémement attentifs à travailler les pare-<lb/>mens des Edifices conſiderables: </s> <s xml:id="echoid-s5301" xml:space="preserve">ils en rendoient les joints preſque <lb/>imperceptibles, ce qui a fait croire, comme il y a toute aparence, <lb/>qu’il leur arrivoit quelquesfois de bâtir ſans mortier, aimant mieux <lb/>tailler les pierres ſi juſtes, que leur ſituation & </s> <s xml:id="echoid-s5302" xml:space="preserve">leur poids puſſent <lb/>fuffire pour donner à l’ouvrage toute la fermeté poſſible. </s> <s xml:id="echoid-s5303" xml:space="preserve">Ils avoient <lb/>encore recours à une pratique aſſés ingenieuſe pour rendre les pa-<lb/>remens polis: </s> <s xml:id="echoid-s5304" xml:space="preserve">ils tailloient bien proprement les faces des pierres <lb/>qui devoient être unies les unes contre les autres, & </s> <s xml:id="echoid-s5305" xml:space="preserve">laiſſoient un <lb/>pouce de velu à celles qui devoient compoſer le parement, quand <lb/>l’ouvrage étoit entierement achevé on recoupoit ces pierres en ra-<lb/>valant; </s> <s xml:id="echoid-s5306" xml:space="preserve">ainſi, quand ils ſe ſervoient de mortier, il ne paroiſſoit preſ-<lb/>que point, & </s> <s xml:id="echoid-s5307" xml:space="preserve">le tout ne ſembloit être compoſé que d’une ſeule <lb/>pierre.</s> <s xml:id="echoid-s5308" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5309" xml:space="preserve">Outre les pierres de parement dont on vient de parler, & </s> <s xml:id="echoid-s5310" xml:space="preserve">que <pb o="69" file="0251" n="259" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> l’on nomme de grand apareil, on en diſtingue encore de deux eſ-<lb/>peces, la premiere eſt le libage qu’on employe pour les fondemens; <lb/></s> <s xml:id="echoid-s5311" xml:space="preserve">la ſeconde eſt le moîlonage ou le petit moîlon, dont on ſe ſert pour garnir <lb/>le milieu des gros murs; </s> <s xml:id="echoid-s5312" xml:space="preserve">c’eſt ici où les Entrepreneurs n’oublient pas <lb/>leurs interêts quand on n’y prend point garde, ils ont grand ſoin de <lb/>faire le parement bien conditionné pour ſuprendre le coup d’œil, <lb/>tandis que le reſte n’eſt compoſé que de bouë & </s> <s xml:id="echoid-s5313" xml:space="preserve">de platras, il eſt <lb/>vrai que cela n’arrive guére dans les ouvrages des Fortifications, <lb/>parce que Meſſieurs les Ingenieurs y aportent tant d’exactitude & </s> <s xml:id="echoid-s5314" xml:space="preserve"><lb/>de ſoin, qu’il eſt aſſés difficile de leur en impoſer, ceux qui ſont ac-<lb/>coûtumés de faire travailler ſachant combien il eſt dangereux de <lb/>s’en raporter à la bonne foi des ouvriers: </s> <s xml:id="echoid-s5315" xml:space="preserve">mais comme j’écris prin-<lb/>cipalement pour ceux qui commencent, & </s> <s xml:id="echoid-s5316" xml:space="preserve">qui n’ont pas une grande <lb/>connoiſſance des travaux, voici en peu de mots ce que l’on doit <lb/>obſerver pour faire faire un bon ouvrage.</s> <s xml:id="echoid-s5317" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5318" xml:space="preserve">Il faut prendre garde de ne jamais laiſſer travailler les Maçons <lb/>qu’aux heures marquées, & </s> <s xml:id="echoid-s5319" xml:space="preserve">qu’ils ayent toûjours des cordeaux <lb/>d’allignemens devant & </s> <s xml:id="echoid-s5320" xml:space="preserve">derriere la muraille, ne permettant pas <lb/>qu’ils faſſent leurs plombées plus hautes que d’un pied ou un pied <lb/>& </s> <s xml:id="echoid-s5321" xml:space="preserve">demi, de ne point laiſſer de mortier qui ne ſoit tiercé & </s> <s xml:id="echoid-s5322" xml:space="preserve">vieux <lb/>de deux jours, ſans ſouffrir qu’on maçonne à ſec comme cela arri-<lb/>ve aſſés ſouvent, ou que tombant dans une autre extrémité on ne <lb/>rempliſſe les trous de poignées de mortier au lieu de Tuilleaux ou <lb/>d’éclats de pierre.</s> <s xml:id="echoid-s5323" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5324" xml:space="preserve">De faire laiſſer des amorcces qui ayent au moins un demi pied <lb/>aux endroits où il y aura repriſe d’ouvrage, & </s> <s xml:id="echoid-s5325" xml:space="preserve">quand on viendra <lb/>à y travailler, ne pas laiſſer recommencer ſur les arraſes ſéches ſans <lb/>y jetter de l’eau.</s> <s xml:id="echoid-s5326" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5327" xml:space="preserve">De ne ſouffrir jamais qu’on mette des calles de bois ſous les car-<lb/>reaux, cordons, tablettes, & </s> <s xml:id="echoid-s5328" xml:space="preserve">autres pierres de parement, ni qu’on <lb/>employe ces pierres ſans qu’elles ayent un lit ſuffiſant pour être bien <lb/>aſſiſes, ne pas laiſſer mettre en œuvre des pierres trop fraichement <lb/>tirées de la Carriere, & </s> <s xml:id="echoid-s5329" xml:space="preserve">qui ne ſoient déchargées de leur bouſin, <lb/>parce que le mortier ne s’y attache pas; </s> <s xml:id="echoid-s5330" xml:space="preserve">de faire enſorte qu’en les <lb/>poſant elles ne faſſent point de boſſes qui excedent le niveau de <lb/>l’ouvrage; </s> <s xml:id="echoid-s5331" xml:space="preserve">mais ſur toute choſe de ne pas ſouffrir qu’on employe <lb/>des pierres de Grès, parce que le mortier ne s’y attache pas, ſoit <lb/>à cauſe que leur pores ſont trop ſerrés, ou qu’elles ne fourniſſent <lb/>point de ſel comme les autres pour durcir & </s> <s xml:id="echoid-s5332" xml:space="preserve">faire ſécher le mor-<lb/>tier, ainſi la meilleure maniere de garnir les murs eſt d’y em-<lb/>ployer de la brique ou du moîlon plat, bien arrangé & </s> <s xml:id="echoid-s5333" xml:space="preserve">entrelaſſé <pb o="70" file="0252" n="260" rhead="LA SCIENCE DES INGENIEURS,"/> de maniere que le milieu des uns réponde aux joints des autres, <lb/>obſervant toûjours de conduire autant qu’il eſt poſſible l’ouvrage <lb/>de niveau ſur toute la longueur & </s> <s xml:id="echoid-s5334" xml:space="preserve">épaiſſeur.</s> <s xml:id="echoid-s5335" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5336" xml:space="preserve">Quand on manque à toutes ces précautions, il arrive que le pa-<lb/>rement, n’étant pas bien lié avec le reſte de l’épaiſſeur, eſt propre-<lb/>ment un mur apliqué contre un autre qui venant à ſe dégrader par <lb/>la ſuite ſe détache en peu de tems, toute la chemiſe tombe, & </s> <s xml:id="echoid-s5337" xml:space="preserve">il <lb/>ne reſte plus qu’un maſſif informe qu’on a bien de la peine à répa-<lb/>rer ſolidement; </s> <s xml:id="echoid-s5338" xml:space="preserve">pour remedier à cet inconvenient on pratique aux <lb/>revêtemens des Fortifications une conſtruction de Maçonnerie qui <lb/>eſt la meilleure (à ce que je crois) qu’on puiſſe imaginer: </s> <s xml:id="echoid-s5339" xml:space="preserve">elle <lb/>ſe fait ordìnairement de brique & </s> <s xml:id="echoid-s5340" xml:space="preserve">de moîlonage; </s> <s xml:id="echoid-s5341" xml:space="preserve">&</s> <s xml:id="echoid-s5342" xml:space="preserve">, comme il y <lb/>a de l’art à bien lier enſemble ces deux materiaux, voici comme <lb/>on les met en œuvre.</s> <s xml:id="echoid-s5343" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5344" xml:space="preserve">Après avoir tracé les fondemens de la muraille & </s> <s xml:id="echoid-s5345" xml:space="preserve">ceux des con-<lb/>treforts relativement aux dimenſions des plans & </s> <s xml:id="echoid-s5346" xml:space="preserve">profils, ſoit pour <lb/>une face de Baſtion, flanc ou courtine, & </s> <s xml:id="echoid-s5347" xml:space="preserve">bâti ces fondemens avec <lb/>les précautions dont il eſt parlé dans le Chapitre précédent; </s> <s xml:id="echoid-s5348" xml:space="preserve">en un <lb/>mot avoir élevé l’ouvrage juſqu’au niveau du fonds du Foſſé, on <lb/>commencera par faire faire trois mortiers differens, le premier ſera <lb/>de ciment compoſé de bons thuilleaux bien battus, & </s> <s xml:id="echoid-s5349" xml:space="preserve">d’un tiers <lb/>de la meilleure Chaux, pour remplir & </s> <s xml:id="echoid-s5350" xml:space="preserve">garnir les joints des pare-<lb/>mens de graiſſerie; </s> <s xml:id="echoid-s5351" xml:space="preserve">le ſecond ſera auſſi compoſé d’un tiers de bonne <lb/>Chaux, & </s> <s xml:id="echoid-s5352" xml:space="preserve">le reſte de ſable fin pour la Maçonnerie du parement; <lb/></s> <s xml:id="echoid-s5353" xml:space="preserve">ſi l’on a deux ſortes de Chaux on prendra la moindre pour le troi-<lb/>ſiéme mortier qui ſera compoſé de petit gravier s’il y en a ſur les <lb/>lieux pour la groſſe Maçonnerie.</s> <s xml:id="echoid-s5354" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5355" xml:space="preserve">On préparera auſſi trois ſortes de pierres: </s> <s xml:id="echoid-s5356" xml:space="preserve">la premiere, pour les <lb/>ſoubaſſemens & </s> <s xml:id="echoid-s5357" xml:space="preserve">les angles, doit être taillée dans ſes lits & </s> <s xml:id="echoid-s5358" xml:space="preserve">joints, <lb/>cizelée & </s> <s xml:id="echoid-s5359" xml:space="preserve">piquée proprement à la petite pointe du marteau, ſes <lb/>faces dreſſées à la regle, & </s> <s xml:id="echoid-s5360" xml:space="preserve">les joints démaigris pour recevoir le mor-<lb/>tier; </s> <s xml:id="echoid-s5361" xml:space="preserve">la ſeconde ſera la brique dont on ſe ſervira pour le parement, <lb/>& </s> <s xml:id="echoid-s5362" xml:space="preserve">la troiſiéme le moîlon pour la garniture du milieu & </s> <s xml:id="echoid-s5363" xml:space="preserve">des con-<lb/>treforts.</s> <s xml:id="echoid-s5364" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5365" xml:space="preserve">On poſera la premiere aſſiſe du parement compoſée de boutiſſes <lb/>& </s> <s xml:id="echoid-s5366" xml:space="preserve">de carreaux, ſi les boutiſſes ſont rares, on en mettra un tiers ſur <lb/>deux tiers de pannereſſes, les unes & </s> <s xml:id="echoid-s5367" xml:space="preserve">les autres ayant leurs faces <lb/>taillées ſuivant le talud du revêtement, & </s> <s xml:id="echoid-s5368" xml:space="preserve">derriere cette premiere <lb/>aſſiſe on couvrira toute la Maçonnerie des fondemens, tant du re-<lb/>vêtement que des contreforts, d’un lit de trois Briques d’épaiſſeur <lb/>poſées à plat bien garnies de mortiers; </s> <s xml:id="echoid-s5369" xml:space="preserve">le commencement de cet <pb o="71" file="0253" n="261" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> ouvrage demande beaucoup de ſoin & </s> <s xml:id="echoid-s5370" xml:space="preserve">de précaution, ce premier <lb/>lit étant poſé, on en fera un autre derriere les pierres du ſoûbaſſement <lb/>qui aura trois briques & </s> <s xml:id="echoid-s5371" xml:space="preserve">demi de largeur ſeulement: </s> <s xml:id="echoid-s5372" xml:space="preserve">ſur celui-ci on <lb/>en fera un ſecond qui ſera moins étendu d’une demi brique, ſur <lb/>ce ſecond un troiſiéme qui ira encore en diminuant d’une demi bri-<lb/>que, & </s> <s xml:id="echoid-s5373" xml:space="preserve">on continuëra de même juſqu’au cinquiéme rang qui ſe ter-<lb/>minera à une brique & </s> <s xml:id="echoid-s5374" xml:space="preserve">demi, en élevant ces rangs des briques, on <lb/>a grand ſoin de bien garnir tout le reſte de l’épaiſſeur du mur & </s> <s xml:id="echoid-s5375" xml:space="preserve"><lb/>des contreforts de moîlon à bain de mortier arraſé ſur tout l’étendu <lb/>de l’ouvrage que l’on conduit toûjours de niveau de même que les <lb/>contreforts aux angles deſquels on met les plus gros moîlons, ob-<lb/>ſervant que la racine ſoit bien liée avec le revêtement pour que <lb/>le tout ne faſſe qu’un corps: </s> <s xml:id="echoid-s5376" xml:space="preserve">quand la Maçonnerie a été élevée de <lb/>niveau au dernier rang de briques dont nous venons de parler, <lb/>pour lors on dit avoir fait une levée que l’on couvre de rechef d’un <lb/>rang de trois briques d’épaiſſeur qui regne generalement ſur tout <lb/>l’ouvrage, & </s> <s xml:id="echoid-s5377" xml:space="preserve">ce rang eſt nommé chaîne, parce qu’effectivement <lb/>il enchaîne pour ainſi dire toutes les parties de l’ouvrage les unes <lb/>avec les autres, après cela l’on recommence tout de nouveau à <lb/>faire une levée de briques de cinq rangs de hauteur allant en di-<lb/>minuant d’une demi brique au premier rang, & </s> <s xml:id="echoid-s5378" xml:space="preserve">ſe terminant à une <lb/>& </s> <s xml:id="echoid-s5379" xml:space="preserve">demi au cinquiéme, le derriere garni de moîlon comme l’on a <lb/>fait pour la premiere levée, & </s> <s xml:id="echoid-s5380" xml:space="preserve">ainſi de ſuite.</s> <s xml:id="echoid-s5381" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5382" xml:space="preserve">D’un autre côté l’on continuë à conduire le parement par aſſiſes <lb/>de boutiſſes & </s> <s xml:id="echoid-s5383" xml:space="preserve">de pannereſſes, les boutiſſes bien enclavées dans l’é-<lb/>paiſſeur du mur, & </s> <s xml:id="echoid-s5384" xml:space="preserve">les pannereſſes ſerrées & </s> <s xml:id="echoid-s5385" xml:space="preserve">maçonnées entre les <lb/>boutiſſes, faiſant toûjours ſuivre à leurs faces le talud de la muraille, <lb/>tant que le ſoûbaſſement ſoit parvenu à la hauteur qu’on jugera à <lb/>propos de lui donner, qui eſt ordinairement de 5 ou 6 pieds plus <lb/>ou moins ſelon la hauteur de l’ouvrage. </s> <s xml:id="echoid-s5386" xml:space="preserve">Le ſommet de la derniere <lb/>aſſiſe du ſoûbaſſement doit être taillé en champ frain de deux pouces: <lb/></s> <s xml:id="echoid-s5387" xml:space="preserve">cette partie du parement ſe fabrique comme nous l’avons dit avec <lb/>du mortier de ciment, de terraſſe, ou de cendrée de Tournay, ſelon <lb/>les Pays où l’on fait travailler, on en uſe de même pour tous les <lb/>autres murs qui ſont ſujets à être environnés d’eau.</s> <s xml:id="echoid-s5388" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5389" xml:space="preserve">Quand le ſoûbaſſement eſt achevé on continuë à élever le reſte <lb/>du parement qui ſe fait de briques ou de moîlon picqué, mais plus <lb/>ordinairement de briques; </s> <s xml:id="echoid-s5390" xml:space="preserve">c’eſt pourquoi j’ai ſupoſé que le profil <lb/> <anchor type="note" xlink:label="note-0253-01a" xlink:href="note-0253-01"/> repreſenté par la Figure 10. </s> <s xml:id="echoid-s5391" xml:space="preserve">étoit fait dans ce goût-là: </s> <s xml:id="echoid-s5392" xml:space="preserve">il exprime <lb/>aſſés bien la diſpoſition des aſſiſes qui compoſent le ſoûbaſſement, <lb/>les chaînes de briques qui ſe font après chaque levée & </s> <s xml:id="echoid-s5393" xml:space="preserve">les cinq <pb o="72" file="0254" n="262" rhead="LA SCIENCE DES INGENIEURS,"/> rangs dont nous avons parlé, qui vont toûjours en diminuant d’une <lb/>demi brique, ainſi comme ce deſſein aide beaucoup à faire enten-<lb/>dre la conſtruction que je me ſuis propoſé de décrire, cela me diſ-<lb/>penſera d’entrer dans bien de petites circonſtances qui ſe préſente-<lb/>ront d’elles-mêmes à l’eſprit, pour peu qu’on y faſſe attention.</s> <s xml:id="echoid-s5394" xml:space="preserve"/> </p> <div xml:id="echoid-div282" type="float" level="3" n="1"> <note position="right" xlink:label="note-0253-01" xlink:href="note-0253-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>8.</note> </div> <p> <s xml:id="echoid-s5395" xml:space="preserve">Si le reſte du parement au-deſſus du ſoubaſſement ſe fait de bri-<lb/>ques, on commence par en aſſeoir un rang que l’on met à plat, & </s> <s xml:id="echoid-s5396" xml:space="preserve"><lb/>qui font face de leur tête: </s> <s xml:id="echoid-s5397" xml:space="preserve">ſur celui-ci on en met un autre à plat <lb/>qui font face de leur longueur, & </s> <s xml:id="echoid-s5398" xml:space="preserve">alternativement une aſſiſe en bou-<lb/>tiſſe, & </s> <s xml:id="echoid-s5399" xml:space="preserve">une autre en pannereſſe à joint recouvert, obſervant de <lb/>ſuivre le talud qui à été reglé par le profil, & </s> <s xml:id="echoid-s5400" xml:space="preserve">toujours de même <lb/>juſqu’au cordon, au contraire du derriere de la muraille qui doit <lb/>être à plomb, auſſi-bien que les contreforts.</s> <s xml:id="echoid-s5401" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5402" xml:space="preserve">En conduiſant le parement, on arme les angles ſaillans de pier-<lb/>re de taille en petit boſſage, d’un pouce & </s> <s xml:id="echoid-s5403" xml:space="preserve">demi de relief poſé par <lb/>aſſiſe reglée, & </s> <s xml:id="echoid-s5404" xml:space="preserve">les deux faces de chaque pierre qui font parement, <lb/>ſont taillées de façon qu’elles forment préciſement un angle égal à <lb/>celui que doit avoir l’ouvrage, ayant attention de donner auſſi à <lb/>ces mêmes façes, le talud que doit avoir le revêtement de la ma-<lb/>niere qu’on le voit repreſenté dans la figure 9. </s> <s xml:id="echoid-s5405" xml:space="preserve">& </s> <s xml:id="echoid-s5406" xml:space="preserve">quand on eſt <lb/>parvenu à la hauteur qu’on veut donner au revêtement, on le ter-<lb/>mine d’un cordon de la même pierre d’un pied de hauteur, taillée <lb/>en demi rond, & </s> <s xml:id="echoid-s5407" xml:space="preserve">poſée en ſaillie d’environ cinq ou ſix pouces, ce <lb/>cordon eſt auſſi compoſé de pannereſſes & </s> <s xml:id="echoid-s5408" xml:space="preserve">de boutiſſes: </s> <s xml:id="echoid-s5409" xml:space="preserve">les pan-<lb/>nereſſes doivent avoir au moins 24. </s> <s xml:id="echoid-s5410" xml:space="preserve">pouces de lit, non compris la <lb/>ſaillie & </s> <s xml:id="echoid-s5411" xml:space="preserve">les boutiſſes trois pieds de queuë, le derriere bien garni <lb/>& </s> <s xml:id="echoid-s5412" xml:space="preserve">conduit à même hauteur, enſuite on éleve quelquefois ſur le <lb/>ſommet de la muraille, un petit mur à plomb devant & </s> <s xml:id="echoid-s5413" xml:space="preserve">derriere, <lb/>auquel on donne 4. </s> <s xml:id="echoid-s5414" xml:space="preserve">pieds de haut & </s> <s xml:id="echoid-s5415" xml:space="preserve">trois dépaiſſeur, pour ſervir <lb/>de revêtement au parapet. </s> <s xml:id="echoid-s5416" xml:space="preserve">Quand la pierre de taille eſt commune <lb/>on le couronne par une tablette qui a un larmier dont la ſaillie eſt <lb/>de 3. </s> <s xml:id="echoid-s5417" xml:space="preserve">ou 4. </s> <s xml:id="echoid-s5418" xml:space="preserve">pouces, ou bien on couvre toute la Maçonnerie <lb/>par une aſſiſe de briques poſées en liaiſon alternative, moitié de <lb/>cant, & </s> <s xml:id="echoid-s5419" xml:space="preserve">moitié de bout, avec leſquels on fait auſſi un larmier <lb/>qui deborde ſeulement d’un pouce, ou d’un pouce & </s> <s xml:id="echoid-s5420" xml:space="preserve">demi, obſer-<lb/>vant de donner au couronnement une pente de 4. </s> <s xml:id="echoid-s5421" xml:space="preserve">pouces, allant <lb/>du derriere au devant, le tout conſtruit à petit joint, en bonne <lb/>liaiſon bien reciré.</s> <s xml:id="echoid-s5422" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5423" xml:space="preserve">Quand on fait des demi revêtemens, on ſuit les mêmes choſes <lb/>qu’on vient de voir, c’eſt-à-dire, que l’on conduit la Maçonnerie <lb/>depuis la derniere retraite des fondemens juſqu’à la hauteur de la <pb o="73" file="0255" n="263" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> ligne de niveau, ou du rez-de-Chauſſée, le reſte de la hauteur ſe <lb/>revêtit de gaſons ou de placages, & </s> <s xml:id="echoid-s5424" xml:space="preserve">on ſe conforme au cinquiéme <lb/>Article du Profil général de Mr. </s> <s xml:id="echoid-s5425" xml:space="preserve">de Vauban.</s> <s xml:id="echoid-s5426" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5427" xml:space="preserve">A l’égard du revêtement des Contreſcarpes, & </s> <s xml:id="echoid-s5428" xml:space="preserve">de ceux des gor-<lb/>ges des ouvrages, la maçonnerie s’en fait avec les mêmes précau-<lb/>tions qu’aux remparts; </s> <s xml:id="echoid-s5429" xml:space="preserve">ainſi, on en peut juger par la figure huitié-<lb/>me.</s> <s xml:id="echoid-s5430" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5431" xml:space="preserve">Comme l’on ſe trouve ſouvent dans la neceſſité de lier de la nou-<lb/>velle maçonnerie avec de la vieille, je m’arrêterai un moment pour <lb/>enſeigner une pratique qu’on ne fera pas mal de ſuivre en pareil cas: <lb/></s> <s xml:id="echoid-s5432" xml:space="preserve">les Maçons y faiſant ordinairement ſi peu d’attention, qu’il arrive <lb/>toûjours que leur ouvrage eſt defectueux en cet endroit-là.</s> <s xml:id="echoid-s5433" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5434" xml:space="preserve">Après avoir detaché une partie de la vielle maçonnerie pour ſe <lb/>donner des amorces, il faut grater le mortier qui ſe trouve ſur la <lb/>pierre, tant qu’il n’en paroiſſe plus que dans le fond des joints, en-<lb/>ſuite netoyer proprement toutes les ordures, de ſorte qu’il n’y reſ-<lb/>te pas de pouſſiere; </s> <s xml:id="echoid-s5435" xml:space="preserve">pour cela il faut, après s’être ſervi du balai, <lb/>avoir de groſſes broſſes, afin que les ſoyes s’introduiſans dans les <lb/>pores les plus imperceptibles en faſſent ſortir tout ce qui s’y trouve, <lb/>car c’eſt ordinairement la poudre répanduë ſur la pierre, qui em-<lb/>pêche le mortier de s’inſinuer dans ſes pores pour faire une bonne <lb/>liaiſon: </s> <s xml:id="echoid-s5436" xml:space="preserve">aprés cette preparation, il faudra jetter ſur la vieille maçon-<lb/>nerie une grande quantité d’eau, à diverſes repriſes, afin qu’elle <lb/>s’y imbibe, & </s> <s xml:id="echoid-s5437" xml:space="preserve">qu’elle acquiere pour ainſi dire une vertu attrac-<lb/>tive; </s> <s xml:id="echoid-s5438" xml:space="preserve">il faut avoir dans un bacquet de la bonne chaux detrempée, <lb/>deſorte qu’elle ſoit graſſe & </s> <s xml:id="echoid-s5439" xml:space="preserve">glutineuſe; </s> <s xml:id="echoid-s5440" xml:space="preserve">pluſieurs manœuvres pren-<lb/>dront des broſſes, les tremperont dans la chaux pour l’imprimer <lb/>ſur la maçonnerie, en frapant à petits coups, afin qu’elle penetre <lb/>dans les joints & </s> <s xml:id="echoid-s5441" xml:space="preserve">les pores de la pierre juſqu’à ce qu’elle en ſoit bien <lb/>imbibée, & </s> <s xml:id="echoid-s5442" xml:space="preserve">qu’on en ait mis une quantité ſufiſante pour que cette <lb/>colle de chaux ſurmonte de 3. </s> <s xml:id="echoid-s5443" xml:space="preserve">à 4. </s> <s xml:id="echoid-s5444" xml:space="preserve">lignes la ſurface de la maçonnerie, <lb/>après quoi on apliquera deſſus du bon mortier pour maçonner comme <lb/>à l’ordinaire, obſervant que la pierre ou la brique ſoient bien entre-<lb/>laſſées avec les amorces, & </s> <s xml:id="echoid-s5445" xml:space="preserve">faſſe une bonne liaiſon; </s> <s xml:id="echoid-s5446" xml:space="preserve">alors la chaux, <lb/>qui ſe trouve entre la vielle & </s> <s xml:id="echoid-s5447" xml:space="preserve">la nouvelle maçonnerie, les unit ſi <lb/>bien enſemble, en s’incorporant dans l’un & </s> <s xml:id="echoid-s5448" xml:space="preserve">dans l’autre, qu’il ſe <lb/>fait peu de tems apres une liaiſon qui rend l’ouvrage plus indiſſo-<lb/>luble à l’endroit de la jonction que par-tout ailleurs, comme l’expe-<lb/>rience l’a fait voir toutes les fois qu’on en a uſé ainſi.</s> <s xml:id="echoid-s5449" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5450" xml:space="preserve">Voilà ce que je m’étois propoſé de direſur la maçonnerie en ge-<lb/>neral: </s> <s xml:id="echoid-s5451" xml:space="preserve">je me ſuis un peu étendu ſur celle des revêtemens de fortifi- <pb o="74" file="0256" n="264" rhead="LA SCIENCE DES INGENIEURS,"/> cations, parce qu’elle apartient particulierement à mon ſujet; </s> <s xml:id="echoid-s5452" xml:space="preserve">mais <lb/>ſi je voulois entrer dans un ſemblable détail pour tout ce qui pour-<lb/>roit demander une conſtruction particuliere, ſelon les differens cas <lb/>qui peuvent ſe preſenter, je n’aurois jamais fini: </s> <s xml:id="echoid-s5453" xml:space="preserve">c’eſt pourquoi <lb/>je me tiendrai à l’idée que je viens de donner, me propoſant pour-<lb/>tant de ne pas negliger dans la ſuite les occaſions où je pourrai <lb/>inſinuer les connoiſſances que je croirai encore neceſſaires, quand il <lb/>ſera queſtion, par exemple, des Ponts, des Voutes, des Ecluſes, <lb/>& </s> <s xml:id="echoid-s5454" xml:space="preserve">autres Ouvrages conſiderables, qui ont une maniere d’être fa-<lb/>briqués, qui leur apartient eſſentiellement.</s> <s xml:id="echoid-s5455" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div284" type="section" level="2" n="87"> <head xml:id="echoid-head225" style="it" xml:space="preserve">Explication de pluſieurs Tables ſervant à déterminer les Di-<lb/>menſions de toute ſorte de Revêtement de Maçonnerie.</head> <p> <s xml:id="echoid-s5456" xml:space="preserve">Depuis que j’ai compoſé le premier livre, il m’eſt venu pluſieurs <lb/> <anchor type="note" xlink:label="note-0256-01a" xlink:href="note-0256-01"/> fois en penſée que bien des gens ne feroient pas grand uſage des <lb/>regles que j’y ai enſeignées, pour trouver l’épaiſſeur des revêtemens, <lb/>à cauſe de la longueur des calculs, & </s> <s xml:id="echoid-s5457" xml:space="preserve">des operations abſtraites, qu’il <lb/>falloit faire, & </s> <s xml:id="echoid-s5458" xml:space="preserve">que le ſur moyen de contenter tout le monde étoit <lb/>de donner des tables dans leſquelles on pût trouver les dimenſions <lb/>de tous les profils qui peuvent s’executer, ſelon les differens taluds <lb/>que l’on voudroit donner aux revêtemens, ſoit pour ceux qui ſou-<lb/>tiendroient des rempars, accompagnés de leurs parapets, ou pour <lb/>les autres, qui, n’ayant point de parapets à ſoutenir, ſerviroient aux <lb/>terraſſes, aux quays, aux chauſſées, aux contreſcarpes, aux gorges <lb/>des ouvrages &</s> <s xml:id="echoid-s5459" xml:space="preserve">c. </s> <s xml:id="echoid-s5460" xml:space="preserve">Mais ces Tables telles que je les conçus d’abord <lb/>me parurent d’un ſi grand travail, que j’heſitai long-tems à les entre-<lb/>prendre; </s> <s xml:id="echoid-s5461" xml:space="preserve">j’en expoſai le deſſein à quelques perſonnes de mes amis, <lb/>qui me firent entendre que de tout ce que je pouvois rapporter <lb/>dans mon livre, rien ne ſeroit plus utile & </s> <s xml:id="echoid-s5462" xml:space="preserve">plus intereſſant: </s> <s xml:id="echoid-s5463" xml:space="preserve">cela <lb/>ſufit pour me determiner & </s> <s xml:id="echoid-s5464" xml:space="preserve">vaincre la repugnance que j’avois à <lb/>m’apliquer pendant un tems conſiderable à un ouvrage auſſi ingrat: <lb/></s> <s xml:id="echoid-s5465" xml:space="preserve">car il faut convenir que le public n’eſt pas toûjours judicieux, ſou-<lb/>vent il ne juge du prix des choſes que par ce qui peut plaire à l’ima-<lb/>gination, & </s> <s xml:id="echoid-s5466" xml:space="preserve">tient fort peu de compte de la peine dont un Auteur <lb/>veut bien ſeul ſe charger, quoi qu’il pourroit être en droit de la par-<lb/>tager avec lui: </s> <s xml:id="echoid-s5467" xml:space="preserve">il me permettra de lui faire ce petit reproche, il <lb/>touvera aſſez dans mon ouvrage dequoi avoir ſa ravanche.</s> <s xml:id="echoid-s5468" xml:space="preserve"/> </p> <div xml:id="echoid-div284" type="float" level="3" n="1"> <note position="left" xlink:label="note-0256-01" xlink:href="note-0256-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>9. & 10.</note> </div> <p> <s xml:id="echoid-s5469" xml:space="preserve">Ayant déja raporté ſur la fin de l’Article 37. </s> <s xml:id="echoid-s5470" xml:space="preserve">du premier Livre des <lb/>Tables pour l’épaiſſeur des revêtemens, on penſera peut-être que <lb/>celles dont je parle ſont à peu près de même; </s> <s xml:id="echoid-s5471" xml:space="preserve">cependant elles <pb o="75" file="0257" n="265" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> ſont bien differentes, car dans les premieres tous les profils ſont <lb/>aſſujettis à un talud, qui eſt toûjours la cinquiéme partie de la hau-<lb/>teur, & </s> <s xml:id="echoid-s5472" xml:space="preserve">on n’y ſuppoſe point de contreforts, au lieu que dans cel-<lb/>le-ci l’on a une ſuite de revêtemens, depuis 10. </s> <s xml:id="echoid-s5473" xml:space="preserve">pieds juſqu’à 100. <lb/></s> <s xml:id="echoid-s5474" xml:space="preserve">qui ont non ſeulement pour talud le 5. </s> <s xml:id="echoid-s5475" xml:space="preserve">de la hauteur, mais le 6. </s> <s xml:id="echoid-s5476" xml:space="preserve"><lb/>le 7. </s> <s xml:id="echoid-s5477" xml:space="preserve">le 8. </s> <s xml:id="echoid-s5478" xml:space="preserve">le 9. </s> <s xml:id="echoid-s5479" xml:space="preserve">ou le 10. </s> <s xml:id="echoid-s5480" xml:space="preserve">ſelon que l’on voudroit choiſir un profil <lb/>plûtôt que l’autre: </s> <s xml:id="echoid-s5481" xml:space="preserve">d’ailleurs, tous les revêtemens ſont accompagnés <lb/>de contreforts, dont les dimenſions ſont raportées pour telle hau-<lb/>teur de rempart que l’on voudra, comme on en va juger par l’ex-<lb/>plication de la 9. </s> <s xml:id="echoid-s5482" xml:space="preserve">& </s> <s xml:id="echoid-s5483" xml:space="preserve">10. </s> <s xml:id="echoid-s5484" xml:space="preserve">planche.</s> <s xml:id="echoid-s5485" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5486" xml:space="preserve">La 9<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5487" xml:space="preserve">planche comprend les dimenſions de tous les revêtemens, <lb/>qui ſoutiendroient des rempars accompagnés de leurs parapets; <lb/></s> <s xml:id="echoid-s5488" xml:space="preserve">mais comme l’on peut donner à ces revêtemens un talud plus ou <lb/>moins conſiderable, cette planche contient ſept tables: </s> <s xml:id="echoid-s5489" xml:space="preserve">les ſix pre-<lb/>mieres ſont compoſées chacune de deux colomnes, dont l’une dé-<lb/>termine l’épaiſſeur qu’il faut donner au ſommet des revêtemens, & </s> <s xml:id="echoid-s5490" xml:space="preserve"><lb/>l’autre celle de la baſe des mêmes revêtemens, pour tous ceux qui <lb/>auroient depuis 10. </s> <s xml:id="echoid-s5491" xml:space="preserve">pieds de hauteur, juſqu’à 100. </s> <s xml:id="echoid-s5492" xml:space="preserve">Par exemple, <lb/>la premiere table comprend les épaiſſeurs des revêtemens qui au-<lb/>roient un 5. </s> <s xml:id="echoid-s5493" xml:space="preserve">de talud: </s> <s xml:id="echoid-s5494" xml:space="preserve">la ſeconde celle des revêtemens qui n’au-<lb/>roient pour talud que la 6. </s> <s xml:id="echoid-s5495" xml:space="preserve">partie de leur hauteur: </s> <s xml:id="echoid-s5496" xml:space="preserve">enfin la 3. </s> <s xml:id="echoid-s5497" xml:space="preserve">4. </s> <s xml:id="echoid-s5498" xml:space="preserve">5. </s> <s xml:id="echoid-s5499" xml:space="preserve"><lb/>& </s> <s xml:id="echoid-s5500" xml:space="preserve">6. </s> <s xml:id="echoid-s5501" xml:space="preserve">table comprennent de ſuite les mêmes épaiſſeurs, pour les revê-<lb/>temens qui auroient pour talud un 7. </s> <s xml:id="echoid-s5502" xml:space="preserve">8. </s> <s xml:id="echoid-s5503" xml:space="preserve">9. </s> <s xml:id="echoid-s5504" xml:space="preserve">ou 10. </s> <s xml:id="echoid-s5505" xml:space="preserve">de leur hauteur.</s> <s xml:id="echoid-s5506" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5507" xml:space="preserve">A l’égard de la 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5508" xml:space="preserve">table, elle comprend trois colomnes qui expri-<lb/>ment les dimenſions des contreforts, qui doivent accompagner <lb/>tous les revêtemens dont il eſt fait mention dans les ſix premieres <lb/>tables; </s> <s xml:id="echoid-s5509" xml:space="preserve">car il eſt bon de remarquer que tous les revêtemens de <lb/>même hauteur, ſoit qu’ils ayent pour talud un 5. </s> <s xml:id="echoid-s5510" xml:space="preserve">un 7. </s> <s xml:id="echoid-s5511" xml:space="preserve">ou 10. </s> <s xml:id="echoid-s5512" xml:space="preserve">doi-<lb/>vent toûjours avoir des contreſorts, dont les dimenſions ſoient les <lb/>mêmes que celles qui ſont marquées dans la 7. </s> <s xml:id="echoid-s5513" xml:space="preserve">table à l’allignement <lb/>qui répond à la hauteur dont il s’agit; </s> <s xml:id="echoid-s5514" xml:space="preserve">d’ailleurs que ces contreforts <lb/>ſont toûjours eſpacés de 18. </s> <s xml:id="echoid-s5515" xml:space="preserve">pieds, de milieu en milieu, ſans que <lb/>cela change jamais pour quelque revêtement que ce ſoit, grand ou <lb/>petit: </s> <s xml:id="echoid-s5516" xml:space="preserve">& </s> <s xml:id="echoid-s5517" xml:space="preserve">en cela je me ſuis conformé à la maxime de Mr. </s> <s xml:id="echoid-s5518" xml:space="preserve">de Vau-<lb/>ban dans ſon Profil genéral, dont j’ai retenu les contreforts, parce <lb/>qu’ils m’ont paru dans une proportion fort raiſonnable. </s> <s xml:id="echoid-s5519" xml:space="preserve">Cependant <lb/>je n’ignore pas que bien des Ingenieurs aiment mieux les eſpacer <lb/>de 15. </s> <s xml:id="echoid-s5520" xml:space="preserve">pieds, de milieu en milieu, que de 18: </s> <s xml:id="echoid-s5521" xml:space="preserve">je ne voi pas bien la <lb/>raiſon de cette perference, puiſque quand le revêtement a une <lb/>épaiſſeur ſuffiſante, & </s> <s xml:id="echoid-s5522" xml:space="preserve">qui met la reſiſtance au-deſſus de la pouſſée <lb/>des terres, il n’y a point de raiſon de multiplier les contreforts <pb o="76" file="0258" n="266" rhead="LA SCIENCE DES INGENIEURS,"/> ſans neceſſité. </s> <s xml:id="echoid-s5523" xml:space="preserve">Si je les ai éloignées de 18. </s> <s xml:id="echoid-s5524" xml:space="preserve">pieds plûtôt que de 15. <lb/></s> <s xml:id="echoid-s5525" xml:space="preserve">ç’a été pour empêcher qu’en augmentant les dimenſions de leurs <lb/>baſes, à meſure que les revêtemens devenoient plus élevés, ils <lb/>ne ſe trouvaſſent trop ſerrés: </s> <s xml:id="echoid-s5526" xml:space="preserve">cela n’empêche pourtant pas dans l’u-<lb/>ſage que l’on fera dans ces tables, qu’on ne puiſſe, ſi l’on veut, ra-<lb/>procher les contreforts les mettant à 15. </s> <s xml:id="echoid-s5527" xml:space="preserve">pieds, & </s> <s xml:id="echoid-s5528" xml:space="preserve">ſuivre exactement <lb/>toutes les autres dimenſions. </s> <s xml:id="echoid-s5529" xml:space="preserve">Si l’on prend ce parti qui me paroît <lb/>aſſez inutile, le revêtement ſera encore beaucoup au-deſſus de l’é-<lb/>quilibre malgré les égards que j’ai eu.</s> <s xml:id="echoid-s5530" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5531" xml:space="preserve">Pour donner l’uſage de ces tables, nous ſupoſerons qu’on veut <lb/>revêtir les faces d’une demi lune, que le revêtement doit avoir <lb/>25. </s> <s xml:id="echoid-s5532" xml:space="preserve">pieds de hauteur depuis la derniere retraite, ou ſi l’on veut <lb/>depuis le fond du foſſé juſqu’au cordon, & </s> <s xml:id="echoid-s5533" xml:space="preserve">qu’on ne veut pour ta-<lb/>lud qu’un 7. </s> <s xml:id="echoid-s5534" xml:space="preserve">de hauteur, on demande quelles doivent être les di-<lb/>menſions des plans & </s> <s xml:id="echoid-s5535" xml:space="preserve">profils, pour que le revêtement ſoit capa-<lb/>ble par ſa reſiſtance de ſoutenir un effort plus grand que celui de <lb/>la pouſſée des terres du rempart & </s> <s xml:id="echoid-s5536" xml:space="preserve">du parapet; </s> <s xml:id="echoid-s5537" xml:space="preserve">je cherche dans la pe-<lb/>tite colomne qui marque la hauteur des revêtemens, le nombre <lb/>25. </s> <s xml:id="echoid-s5538" xml:space="preserve">& </s> <s xml:id="echoid-s5539" xml:space="preserve">en ſuivant le même allignement, je paſſe à la 3. </s> <s xml:id="echoid-s5540" xml:space="preserve">table, qui <lb/>montre qu’il faut donner 6. </s> <s xml:id="echoid-s5541" xml:space="preserve">pieds 1. </s> <s xml:id="echoid-s5542" xml:space="preserve">pouce 11. </s> <s xml:id="echoid-s5543" xml:space="preserve">lignes d’épaiſſeur, <lb/>au ſommet du revêtement en queſtion, & </s> <s xml:id="echoid-s5544" xml:space="preserve">9. </s> <s xml:id="echoid-s5545" xml:space="preserve">pieds 8. </s> <s xml:id="echoid-s5546" xml:space="preserve">pouces 9. <lb/></s> <s xml:id="echoid-s5547" xml:space="preserve">lignes à la baſe, de-là en ſuivant toûjours le même allignement, je <lb/>paſſe à la 7. </s> <s xml:id="echoid-s5548" xml:space="preserve">table pour voir quelles doivent être les dimenſions des <lb/>contreforts, je trouve qu’il faut leur donner 7. </s> <s xml:id="echoid-s5549" xml:space="preserve">pieds de longueur <lb/>4. </s> <s xml:id="echoid-s5550" xml:space="preserve">pieds 6. </s> <s xml:id="echoid-s5551" xml:space="preserve">pouces à la racine & </s> <s xml:id="echoid-s5552" xml:space="preserve">3. </s> <s xml:id="echoid-s5553" xml:space="preserve">pieds à la queuë, obſervant de <lb/>les eſpacer de 18. </s> <s xml:id="echoid-s5554" xml:space="preserve">pieds de milieu en milieu; </s> <s xml:id="echoid-s5555" xml:space="preserve">ſi au lieu d’un 7. </s> <s xml:id="echoid-s5556" xml:space="preserve">de <lb/>talud, on ne vouloit donner qu’un 9<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5557" xml:space="preserve">de la hauteur, en ſuivant <lb/>toûjours l’allignement de 25. </s> <s xml:id="echoid-s5558" xml:space="preserve">pieds, il faudroit prendre les dimen-<lb/>ſions du ſommet & </s> <s xml:id="echoid-s5559" xml:space="preserve">de la baſe dans la 5<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5560" xml:space="preserve">colomne, & </s> <s xml:id="echoid-s5561" xml:space="preserve">l’on trouve-<lb/>ra 7. </s> <s xml:id="echoid-s5562" xml:space="preserve">pieds 1. </s> <s xml:id="echoid-s5563" xml:space="preserve">pouce 7. </s> <s xml:id="echoid-s5564" xml:space="preserve">lignes pour l’un, & </s> <s xml:id="echoid-s5565" xml:space="preserve">9. </s> <s xml:id="echoid-s5566" xml:space="preserve">pieds 10. </s> <s xml:id="echoid-s5567" xml:space="preserve">pouces <lb/>11. </s> <s xml:id="echoid-s5568" xml:space="preserve">lignes pour l’autre, & </s> <s xml:id="echoid-s5569" xml:space="preserve">les contreforts comme ci-devant.</s> <s xml:id="echoid-s5570" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5571" xml:space="preserve">A l’égard des tables contenuës dans la 10<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5572" xml:space="preserve">planche, elles ſont <lb/>entierement ſemblables aux precedentes; </s> <s xml:id="echoid-s5573" xml:space="preserve">la ſeule difference eſt que <lb/>les unes repondent à des revêtemens, qui auroient un parapet à <lb/>ſoutenir, au lieu que les autres ſervent pour les revêtemens, dont <lb/>le ſommet ſeroit de niveau avec la ſurface de l’ouvrage dont il s’a-<lb/>git; </s> <s xml:id="echoid-s5574" xml:space="preserve">par exemple, ſi l’on vouloit ſavoir quelles doivent être les di-<lb/>menſions du revêtement d’une contreſcarpe, qui auroit 15. </s> <s xml:id="echoid-s5575" xml:space="preserve">pieds <lb/>de hauteur, & </s> <s xml:id="echoid-s5576" xml:space="preserve">auquel on voudroit donner un 8<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5577" xml:space="preserve">de talud, je cher-<lb/>che dans la colomne des hauteurs, le nombre 15. </s> <s xml:id="echoid-s5578" xml:space="preserve">& </s> <s xml:id="echoid-s5579" xml:space="preserve">en ſuivant le <lb/>même allignement, je paſſe à la 4<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5580" xml:space="preserve">table où je trouve qu’il faut <pb o="77" file="0259" n="267" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> donner 2. </s> <s xml:id="echoid-s5581" xml:space="preserve">pieds 9. </s> <s xml:id="echoid-s5582" xml:space="preserve">pouces 10. </s> <s xml:id="echoid-s5583" xml:space="preserve">lignes au ſommet, & </s> <s xml:id="echoid-s5584" xml:space="preserve">4. </s> <s xml:id="echoid-s5585" xml:space="preserve">pieds 8. <lb/></s> <s xml:id="echoid-s5586" xml:space="preserve">pouces 4. </s> <s xml:id="echoid-s5587" xml:space="preserve">lignes à la baſe, de là a la 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5588" xml:space="preserve">où je remarque que les <lb/>contreforts du même revêtement doivent avoir 5. </s> <s xml:id="echoid-s5589" xml:space="preserve">pieds de lon-<lb/>gueur, 3. </s> <s xml:id="echoid-s5590" xml:space="preserve">pieds 6. </s> <s xml:id="echoid-s5591" xml:space="preserve">pouces en racine, & </s> <s xml:id="echoid-s5592" xml:space="preserve">2. </s> <s xml:id="echoid-s5593" xml:space="preserve">pieds 4. </s> <s xml:id="echoid-s5594" xml:space="preserve">pouces à la queuë <lb/>toûjours eſpacés de 18. </s> <s xml:id="echoid-s5595" xml:space="preserve">pieds de milieu en milieu.</s> <s xml:id="echoid-s5596" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5597" xml:space="preserve">On a ſupoſé généralement dans toutes ces tables, que les contre-<lb/>forts étoient auſſi élevés que le ſommet des revêtemens, auxquels <lb/>ils repondoient, ce qui ſe pratique toûjours, quand il s’agit de ſou-<lb/>tenir un rempart qui eſt accompagné d’un parapet, & </s> <s xml:id="echoid-s5598" xml:space="preserve">lors que ce <lb/>parapet eſt revêtu d’une petire muraille de 4. </s> <s xml:id="echoid-s5599" xml:space="preserve">pieds de hauteur, qu’on <lb/>éleve au deſſus du cordon; </s> <s xml:id="echoid-s5600" xml:space="preserve">mais, quand il s’agit de demi revête-<lb/>ment, ou de ſoutenir une contreſcarpe ou la gorge d’un ouvrage, <lb/>alors le ſommet des contreforts ſe termine à un pied ou 1. </s> <s xml:id="echoid-s5601" xml:space="preserve">pied & </s> <s xml:id="echoid-s5602" xml:space="preserve"><lb/>demi plus bas que celui du revêtement, afin qu’il n’y ait que cette <lb/>partie de la maçonnerie qui paroiſſe dehors, ainſi on pourra toûjours <lb/>avoir égard à ce que je viens de dire, ſans aprehender que le revê-<lb/>tement en ſoit moins ſolide, quoique la hauteur des contreforts <lb/>diminuë de quelque choſe.</s> <s xml:id="echoid-s5603" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5604" xml:space="preserve">Pour calculer ces Tables j’ai ſuivi exactement ce qui a été enſei-<lb/>gné à la fin de l’article 51. </s> <s xml:id="echoid-s5605" xml:space="preserve">du premier Livre au ſujet du Profil ge-<lb/>neral de Mr. </s> <s xml:id="echoid-s5606" xml:space="preserve">de Vauban: </s> <s xml:id="echoid-s5607" xml:space="preserve">c’eſt-à-dire, que j’ai regardé l’équation <lb/>y = 2bf - {2dd/3} - {2phg - 2phd/q} + nn - n, comme une formule <lb/>generale qui pouvoit s’apliquer à toute ſorte de revêtement dont <lb/>les dimenſions des contreforts étoient données auſſi-bien que la hau-<lb/>teur des revêtemens & </s> <s xml:id="echoid-s5608" xml:space="preserve">leur talud, & </s> <s xml:id="echoid-s5609" xml:space="preserve">qu’il n’étoit plus queſtion que <lb/>de trouver l’épaiſſeur du ſommet relativement à la pouſſée des terres <lb/>qu’il falloit ſoûtenir; </s> <s xml:id="echoid-s5610" xml:space="preserve">ainſi je me ſuis ſervi des Tables des puiſſances <lb/>équivalantes à la pouſſée des terres qu’on a raporté dans l’Article <lb/>37. </s> <s xml:id="echoid-s5611" xml:space="preserve">& </s> <s xml:id="echoid-s5612" xml:space="preserve">c’eſt dans cette occaſion où je me ſuis apperçû combien il <lb/>étoit commode d’avoir des expreſſions qui fuſſent équivalantes à ces <lb/>puiſſances, puiſque ſi j’avois été obligé de les chercher à meſure que <lb/>j’en ai eû beſoin, la 9<emph style="sub">e</emph> & </s> <s xml:id="echoid-s5613" xml:space="preserve">10<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5614" xml:space="preserve">Planche m’auroit coûté plus de qua-<lb/>tre mois de travail continuel, comme on en peut juger par l’exem-<lb/>ple qui eſt raporté à la fin du 51<emph style="sub">e</emph> Article. </s> <s xml:id="echoid-s5615" xml:space="preserve">J’ajoûterai, que j’ai toû-<lb/>jours ſupoſé les puiſſances équivalentes à la pouſſée des terres plus <lb/>fortes d’un 6. </s> <s xml:id="echoid-s5616" xml:space="preserve">qu’elles ne l’étoient effectivement, afin que les revê-<lb/>temens fuſſent au-deſſus de l’équilibre; </s> <s xml:id="echoid-s5617" xml:space="preserve">& </s> <s xml:id="echoid-s5618" xml:space="preserve">que je crois qu’il n’eſt pas <lb/>poſſible d’aporter plus d’exactitude que j’en ai eû pour rendre ces <lb/>Tables auſſi correctes qu’on le peut déſirer: </s> <s xml:id="echoid-s5619" xml:space="preserve">c’eſt pourquoi quand <lb/>on trouvera l’occaſion d’en faire uſage, on peut s’en ſervir en toute <pb o="78" file="0260" n="268" rhead="LA SCIENCE DES INGENIEURS,"/> fûreté ſans qu’il ſoit beſoin de rien augmenter ni diminuer des di-<lb/>menſions qu’on y raporte, à moins que ce ne ſoit pour éviter l’em-<lb/>barras des petites parties: </s> <s xml:id="echoid-s5620" xml:space="preserve">par exemple, on pourra ſupprimer les <lb/>lignes quoique je les aye raportées ſcrupuleuſement de même que <lb/>le calcul les a donné: </s> <s xml:id="echoid-s5621" xml:space="preserve">car 4 ou 5 lignes de plus ou de moins, ni <lb/>même deux ou trois pouces quand il s’agit de grands revêtemens, <lb/>ſont un trop petit objet dans la pratique pour s’en mettre en peine; <lb/></s> <s xml:id="echoid-s5622" xml:space="preserve">cependant, il vaut mieux mettre plus que moins.</s> <s xml:id="echoid-s5623" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5624" xml:space="preserve">Comme la hauteur des revêtemens de toutes ces Tables aug-<lb/>mentent toûjours de 5 pieds depuis 10 juſqu’à 100, il n’y a point <lb/>de hauteur de rempart qu’on ne rencontre à peu près ſemblable à <lb/>celles qui y ſont raportées; </s> <s xml:id="echoid-s5625" xml:space="preserve">car s’il s’agiſſoit d’un revêtement de 31 <lb/>ou 32 pieds, qui ſont deux nombres qui ne ſe trouvent pas dans la <lb/>colomne des hauteurs, on pourra prendre les dimenſions qui répon-<lb/>dent aux revêtemens de 30 pieds, ſans qu’on ait lieu d’aprehender <lb/>qu’elles ſoient trop foibles, puiſqu’elles mettront toujours le revê-<lb/>tement au-deſſus de l’équilibre, à cauſe de l’augmentation que nous <lb/>avons fait à la puiſſance agiſſante: </s> <s xml:id="echoid-s5626" xml:space="preserve">de même s’il s’agiſſoit d’un revê-<lb/>tement de 33 ou 34 pieds, on pourroit prendre les dimenſions qui <lb/>apartiennent à celui de 35, quoiqu’un peu plus fortes qu’elles ne de-<lb/>vroient être, en un mot on prendra toûjours les dimenſions du re-<lb/>vêtement dont la hauteur aprochera le plus de celui qu’on a deſſein <lb/>de conſtruire.</s> <s xml:id="echoid-s5627" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5628" xml:space="preserve">Il eſt bon de remarquer que les dimenſions des contreforts aug-<lb/>mentant en progreſſion d’Arithmetique, leurs baſes doivent aug-<lb/>menter en ſuperficie dans la raiſon des quarrés de leurs côtés ho-<lb/>mologues, & </s> <s xml:id="echoid-s5629" xml:space="preserve">prenant pour côté homologue la longueur de chaque <lb/>contrefort, c’eſt-à-dire 4. </s> <s xml:id="echoid-s5630" xml:space="preserve">5. </s> <s xml:id="echoid-s5631" xml:space="preserve">6. </s> <s xml:id="echoid-s5632" xml:space="preserve">7. </s> <s xml:id="echoid-s5633" xml:space="preserve">8. </s> <s xml:id="echoid-s5634" xml:space="preserve">9. </s> <s xml:id="echoid-s5635" xml:space="preserve">10. </s> <s xml:id="echoid-s5636" xml:space="preserve">11. </s> <s xml:id="echoid-s5637" xml:space="preserve">12. </s> <s xml:id="echoid-s5638" xml:space="preserve">13. </s> <s xml:id="echoid-s5639" xml:space="preserve">14. </s> <s xml:id="echoid-s5640" xml:space="preserve">15. </s> <s xml:id="echoid-s5641" xml:space="preserve">16. <lb/></s> <s xml:id="echoid-s5642" xml:space="preserve">17. </s> <s xml:id="echoid-s5643" xml:space="preserve">18. </s> <s xml:id="echoid-s5644" xml:space="preserve">19. </s> <s xml:id="echoid-s5645" xml:space="preserve">20. </s> <s xml:id="echoid-s5646" xml:space="preserve">21. </s> <s xml:id="echoid-s5647" xml:space="preserve">22. </s> <s xml:id="echoid-s5648" xml:space="preserve">leurs baſes augmenteront dans le raport de <lb/>16. </s> <s xml:id="echoid-s5649" xml:space="preserve">25. </s> <s xml:id="echoid-s5650" xml:space="preserve">36. </s> <s xml:id="echoid-s5651" xml:space="preserve">49. </s> <s xml:id="echoid-s5652" xml:space="preserve">64. </s> <s xml:id="echoid-s5653" xml:space="preserve">81. </s> <s xml:id="echoid-s5654" xml:space="preserve">100. </s> <s xml:id="echoid-s5655" xml:space="preserve">121. </s> <s xml:id="echoid-s5656" xml:space="preserve">144. </s> <s xml:id="echoid-s5657" xml:space="preserve">169. </s> <s xml:id="echoid-s5658" xml:space="preserve">196. </s> <s xml:id="echoid-s5659" xml:space="preserve">225. </s> <s xml:id="echoid-s5660" xml:space="preserve">256. </s> <s xml:id="echoid-s5661" xml:space="preserve">289. </s> <s xml:id="echoid-s5662" xml:space="preserve"><lb/>324. </s> <s xml:id="echoid-s5663" xml:space="preserve">361. </s> <s xml:id="echoid-s5664" xml:space="preserve">400. </s> <s xml:id="echoid-s5665" xml:space="preserve">441. </s> <s xml:id="echoid-s5666" xml:space="preserve">484. </s> <s xml:id="echoid-s5667" xml:space="preserve">Or comme les derniers quarrés ſont bien <lb/>plus grands à proportion que les premiers, il s’enſuit que les baſes <lb/>des contreforts, par conſequent les contreforts mêmes, augmentent <lb/>beaucoup plus à proportion que ne font les revêtemens. </s> <s xml:id="echoid-s5668" xml:space="preserve">Mais comme <lb/>les contreforts ne peuvent augmenter plus qu’ils ne devroient na-<lb/>turellement, ſans que les épaiſſeurs du ſommet & </s> <s xml:id="echoid-s5669" xml:space="preserve">de la baſe des re-<lb/>vêtemens ne diminuënt, il s’enſuit que les differences des épaiſſeurs <lb/>marquées dans les Tables, au lieu d’augmenter, doivent plûtôt di-<lb/>minuer à meſure que les revêtemens ſont plus élevés; </s> <s xml:id="echoid-s5670" xml:space="preserve">c’eſt auſſi <lb/>ce que l’on voit dans toutes les colomnes, puiſque les derniers <lb/>nombres ſont plus petits à proportion que les premiers, ce qui m’a-</s> </p> <pb file="0261" n="269"/> <pb file="0261a" n="270"/> <p> <s xml:id="echoid-s5671" xml:space="preserve">TABLE pour re’gler l’epaisseur qu’il faut donner au Sommet et à la base des Revêtemens des Remparts <lb/>de fortifications, pour ceux qui auroient depuis 10. </s> <s xml:id="echoid-s5672" xml:space="preserve">pieds jusqu’a 100 de hauteur, re’lativement aux dife’rens <lb/>taluds qu’on voudroit leur donner avec les dimensions de leurs contreforts, observant que ladistance <lb/>de ces contreforts doit être de 18. </s> <s xml:id="echoid-s5673" xml:space="preserve">pieds de milieu en milieu. </s> <s xml:id="echoid-s5674" xml:space="preserve"># Las<emph style="sub">ce</emph> des Ing<emph style="sub">rs</emph>. </s> <s xml:id="echoid-s5675" xml:space="preserve">liv III. </s> <s xml:id="echoid-s5676" xml:space="preserve">pl. </s> <s xml:id="echoid-s5677" xml:space="preserve">9. </s> <s xml:id="echoid-s5678" xml:space="preserve">pag. </s> <s xml:id="echoid-s5679" xml:space="preserve">78.</s> <s xml:id="echoid-s5680" xml:space="preserve"/> </p> <note style="it" position="right" xml:space="preserve">Hauteur \\ des \\ Revête- \\ mens. ### Epaisseur \\ au Sommet\\ pour un 5<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 5<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 6<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 6<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 7<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 7<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 8<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 8<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pourun 9<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 9<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 10<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 10<emph style="sub">e</emph>. \\ de talud. # Longueur \\ des \\ Contreforts. # # Epaisseur \\ des contre @ \\ forts en \\ Racine. # # Epaisseur \\ des contre@ \\ forts à la \\ queüe. # Hauteur \\ des \\ Revête@ \\ mens. <lb/>pieds # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pieds. # pie. # pou. # pie. # pou # pieds <lb/>10 # 3. # 5. # 4. # 5. # 5. # 4. # 3. # 8. # 11. # 5. # 4. # 11. # 3. # 11. # 5. # 5. # 4. # 6. # 4. # 1. # 3. # 5. # 4. # 3. # 4. # 2. # 9. # 5. # 4. # 1. # 4. # 4. # 3. # 5. # 4. # 0. # 4. # 3. # 0. # 2. # 0. # 10 <lb/>15 # 4. # 1. # 4. # 7. # 1. # 4. # 4. # 6. # 9. # 7. # 0. # 9. # 4. # 10. # 8. # 7. # 0. # 4. # 5. # 1. # 8. # 7. # 0. # 2. # 5. # 3. # 1. # 6. # 11. # 1. # 5. # 3. # 1. # 6. # 9. # 1. # 5. # 3. # 6. # 2. # 4. # 15 <lb/>20 # 4. # 8. # 8. # 8. # 8. # 8. # 5. # 3. # 9. # 8. # 7. # 9. # 5. # 9. # 4. # 8. # 7. # 7. # 6. # 0. # 8. # 8. # 6. # 8. # 6. # 3. # 11. # 8. # 6. # 7. # 6. # 6. # 5. # 8. # 6. # 5. # 6. # 4. # 0. # 2. # 8. # 20 <lb/>25 # 5. # 2. # 0. # 10. # 2. # 0. # 5. # 10. # 7. # 10. # 0. # 7. # 6. # 1. # 11. # 9. # 8. # 9. # 6. # 9. # 11. # 9. # 11. # 5. # 7. # 1. # 7. # 9. # 10. # 11. # 7. # 4. # 8. # 9. # 10. # 8. # 7. # 4. # 6. # 3. # 0. # 25 <lb/>30 # 5. # 5. # 9. # 11. # 5. # 9. # 6. # 5. # 3. # 11. # 5. # 3. # 6. # 9. # 11. # 11. # 1. # 4. # 7. # 6. # 4. # 11. # 3. # 4. # 7. # 8. # 9. # 11. # 0. # 9. # 8. # 0. # 6. # 11. # 0. # 6. # 8. # 5. # 0. # 3. # 4. # 30 <lb/>35 # 5. # 8. # 3. # 12. # 8. # 3. # 6. # 8. # 4. # 12. # 6. # 4. # 7. # 4. # 11. # 12. # 4. # 11. # 7. # 11. # 9. # 12. # 4. # 3. # 8. # 5. # 0. # 12. # 3. # 8. # 8. # 9. # 4. # 12. # 3. # 4. # 9. # 5. # 6. # 3. # 8. # 35 <lb/>40 # 5. # 10. # 7. # 13. # 10. # 7. # 7. # 0. # 9. # 13. # 8. # 9. # 7. # 8. # 4. # 13. # 4. # 10. # 8. # 2. # 9. # 13. # 2. # 9. # 8. # 11. # 10. # 13. # 5. # 2. # 9. # 4. # 8. # 13. # 4. # 8. # 10. # 6. # 0 # 4. # 0. # 40 <lb/>45 # 6. # 0. # 6. # 15. # 0. # 6. # 7. # 3. # 0. # 14. # 9. # 0. # 8. # 3. # 0. # 14. # 8. # 1. # 8. # 11. # 7. # 14. # 7. # 1. # 9. # 6. # 3. # 14. # 6. # 3. # 9. # 11. # 3. # 14. # 5. # 9. # 11. # 6. # 6. # 4. # 4. # 45 <lb/>50 # 6. # 1. # 8. # 16. # 1. # 8. # 7. # 6. # 9. # 15. # 10. # 9. # 8. # 7. # 5. # 15. # 9. # 1. # 9. # 4. # 8. # 15. # 7. # 8. # 10. # 0. # 5. # 15. # 7. # 1. # 10. # 6. # 3. # 15. # 6. # 3. # 12. # 7. # 0. # 4. # 8. # 50 <lb/>55 # 6. # 2. # 9. # 17. # 2. # 9. # 7. # 10. # 2. # 17. # 0. # 2. # 8. # 11. # 0. # 16. # 9. # 3. # 9. # 9. # 5. # 16. # 7. # 11. # 10. # 5. # 8. # 16. # 7. # 0. # 11. # 0. # 3. # 16. # 6. # 3. # 13. # 7. # 6. # 5. # 0. # 55 <lb/>60 # 6. # 3. # 4. # 18. # 3. # 4. # 8. # 0. # 3. # 18. # 0. # 3. # 9. # 2. # 6. # 17. # 9. # 4. # 10. # 1. # 10. # 17. # 7. # 10. # 10. # 10. # 10. # 17. # 6. # 10. # 11. # 6. # 1. # 17. # 6. # 1. # 14. # 8. # 0. # 5. # 4. # 60 <lb/>65 # 6. # 4. # 6. # 19. # 4. # 6. # 8. # 3. # 9. # 19. # 1. # 9. # 9. # 6. # 4. # 18. # 9. # 7. # 10. # 7. # 7. # 18. # 9. # 1. # 11. # 3. # 4. # 18. # 6. # 0. # 12. # 1. # 2. # 18. # 7. # 2. # 15. # 8. # 6. # 5. # 8. # 65 <lb/>70 # 6. # 5. # 7. # 20. # 5. # 7. # 8. # 6. # 0. # 20. # 2. # 0. # 9. # 9. # 3. # 19. # 9. # 3. # 10. # 9. # 3. # 19. # 6. # 3. # 11. # 6. # 6. # 19. # 3. # 10. # 12. # 5. # 2. # 19. # 5. # 2. # 16. # 9. # 0. # 6. # 0. # 70 <lb/>75 # 6. # 6. # 6. # 21. # 6. # 6. # 8. # 7. # 9. # 21. # 1. # 9. # 9. # 10. # 9. # 20. # 7. # 3. # 11. # 1. # 6. # 20. # 6. # 0. # 11. # 10. # 8. # 20. # 2. # 8. # 12. # 8. # 8. # 20. # 2. # 8. # 17. # 9. # 6. # 6. # 4. # 75 <lb/>80 # 6. # 7. # 4. # 22. # 7. # 4. # 8. # 8. # 3. # 22. # 0. # 3. # 10. # 0. # 3. # 21. # 5. # 4. # 11. # 3. # 3. # 21. # 3. # 3. # 12. # 1. # 5. # 21. # 0. # 1. # 13. # 0. # 9. # 21. # 0. # 9. # 18. # 10. # 0. # 6. # 8. # 80 <lb/>85 # 6. # 8. # 2. # 23. # 8. # 2. # 8. # 9. # 6. # 22. # 11. # 0. # 10. # 2. # 5. # 22. # 4. # 1. # 11. # 5. # 3. # 22. # 0. # 9. # 12. # 3. # 7. # 21. # 8. # 11. # 13. # 4. # 11. # 21. # 10. # 11. # 19. # 10. # 6. # 7. # 0. # 85 <lb/>90 # 6. # 9. # 6. # 24. # 9. # 6. # 8. # 10. # 3. # 23. # 10. # 4. # 10. # 3. # 11. # 23. # 2. # 2. # 11. # 7. # 9. # 22. # 10. # 9. # 12. # 5. # 4. # 22. # 5. # 4. # 13. # 7. # 9. # 22. # 7. # 9. # 20. # 11. # 0. # 7. # 4. # 90 <lb/>95 # 6. # 11. # 6. # 25. # 11. # 6. # 8. # 11. # 0. # 24. # 9. # 0. # 10. # 4. # 9. # 23. # 11. # 7. # 11. # 8. # 4. # 23. # 6. # 11. # 12. # 7. # 4. # 23. # 2. # 0. # 13. # 9. # 7. # 23. # 3. # 7. # 21. # 11. # 6. # 7. # 8. # 95 <lb/>100 # 7. # 0. # 0. # 27. # 0. # 0. # 9. # 0. # 0. # 25. # 8. # 0. # 10. # 6. # 0. # 24. # 9. # 5. # 11. # 9. # 2. # 24. # 3. # 2. # 12. # 9. # 0. # 23. # 10. # 4. # 14. # 0. # 6. # 24. # 0. # 6. # 22. # 12. # 0. # 8. # 0. # 100 <lb/></note> <pb file="0262" n="271"/> <pb file="0263" n="272"/> <pb file="0263a" n="273"/> <p> <s xml:id="echoid-s5681" xml:space="preserve">TABLE pour re’gler l’épaisseur qu’il faut donner au Sommet et à la base des Revêtemens qui ne soutiennent point de <lb/>Parapets, tels que sont ceux des terrasses, des quais, des contrescarpes et Gorges des ouvrages qui auroient depuis 10. </s> <s xml:id="echoid-s5682" xml:space="preserve">pieds <lb/>jusqu’a 100. </s> <s xml:id="echoid-s5683" xml:space="preserve">de hauteur re’lativement aux diffe’rens taluds qu’on voudroit leur donner, avec les dimensions des contreforts, <lb/>observant que la distance de ces Contreforts doitêtre de 18. </s> <s xml:id="echoid-s5684" xml:space="preserve">pieds de milieu en milieu. </s> <s xml:id="echoid-s5685" xml:space="preserve"># Las<emph style="sub">ce</emph>. </s> <s xml:id="echoid-s5686" xml:space="preserve">des Ing<emph style="sub">rs</emph>. </s> <s xml:id="echoid-s5687" xml:space="preserve">liv. </s> <s xml:id="echoid-s5688" xml:space="preserve">III. </s> <s xml:id="echoid-s5689" xml:space="preserve">pl. </s> <s xml:id="echoid-s5690" xml:space="preserve">10. </s> <s xml:id="echoid-s5691" xml:space="preserve">pag. </s> <s xml:id="echoid-s5692" xml:space="preserve">78.</s> <s xml:id="echoid-s5693" xml:space="preserve"/> </p> <note style="it" position="right" xml:space="preserve">hauteur \\ des \\ Revete \\ mens. ### Epaisseur \\ au Sommet \\ pour un 5<emph style="sub">e</emph>, \\ de talud. ### Epaisseur \\ sur la base \\ pour un 5<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 6<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ surla base \\ pour un 6<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 7<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ surla base \\ pour un 7<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 8<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 8<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 9<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ sur la base \\ pour un 9<emph style="sub">e</emph> \\ de talud. ### Epaisseur \\ au Sommet \\ pour un 10<emph style="sub">e</emph>. \\ de talud. ### Epaisseur \\ surla base \\ pour un 10<emph style="sub">e</emph>. \\ de talud. # Longueur \\ des \\ Contreforts. # # Epaisseur \\ des Contre- \\ forts en \\ Racine. # # Epaisseur \\ des Contre@ \\ forts á la \\ queüe # hauteur \\ des \\ Revête- \\ mens <lb/>pieds. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pi. # po. # lig. # pieds. # pi. # po. # pi. # po. # pieds. <lb/>10. # 1. # 3. # 0. # 3. # 3. # 0. # 1. # 6. # 5. # 3. # 2. # 5. # 1. # 8. # 11. # 3. # 2. # 0. # 1. # 10. # 8. # 3. # 1. # 8. # 2. # 0. # 1. # 3. # 1. # 5. # 2. # 1. # 4. # 3. # 1. # 4. # 4. # 3. # 0. # 2. # 0. # 10 <lb/>15. # 1. # 10. # 2. # 4. # 10. # 2. # 2. # 3. # 2. # 4. # 9. # 2. # 2. # 7. # 0. # 4. # 8. # 8. # 2. # 9. # 10. # 4. # 8. # 4 # 3. # 0. # 0. # 4. # 8. # 0. # 3. # 1. # 8. # 4. # 7. # 8. # 5. # 3. # 6. # 2. # 4. # 15. <lb/>20. # 2. # 4. # 5. # 6. # 4. # 5. # 2. # 11. # 2. # 6. # 3. # 2. # 3. # 4. # 10. # 6. # 3. # 1. # 3. # 7. # 10. # 6. # 1. # 10. # 3. # 10. # 10. # 6. # 1. # 6. # 4. # 1. # 8. # 6. # 0. # 8. # 6. # 4. # 0. # 2. # 8. # 20. <lb/>25. # 2. # 10. # 8. # 7. # 10. # 8. # 3. # 6. # 2. # 7. # 8. # 2. # 4. # 0. # 3. # 7. # 7. # 1. # 4. # 5. # 1. # 7. # 6. # 7. # 4. # 8. # 9. # 7. # 6. # 1. # 4. # 11. # 7. # 7. # 5. # 7. # 7. # 4. # 6. # 3. # 0. # 25. <lb/>30. # 3. # 3. # 6. # 9. # 3. # 6. # 4. # 3. # 5. # 9. # 3. # 5. # 4. # 8. # 3. # 8. # 11. # 8. # 5. # 3. # 7. # 8. # 11. # 7. # 5. # 6. # 9. # 8. # 10. # 9. # 5. # 10. # 7. # 8. # 10. # 7. # 8. # 5. # 0. # 3. # 4. # 30. <lb/>35. # 3. # 8. # 0. # 10. # 8. # 0. # 4. # 4. # 7. # 10. # 5. # 7. # 5. # 4. # 2. # 10. # 4. # 2. # 5. # 10. # 10. # 10. # 3. # 4. # 6. # 3. # 11. # 10. # 2. # 7. # 6. # 8. # 8. # 10. # 1. # 6. # 9. # 5. # 6. # 3. # 8. # 35. <lb/>40. # 4. # 0. # 0. # 12. # 0. # 0. # 5. # 1. # 3. # 11. # 9. # 3. # 5. # 11. # 3. # 11. # 7. # 9. # 6. # 6. # 7. # 11. # 6. # 7. # 7. # 0. # 5. # 11. # 5. # 11. # 7. # 5. # 3. # 11. # 5. # 3. # 10. # 6. # 0. # 4. # 0. # 40. <lb/>45. # 4. # 3. # 3. # 13. # 3. # 3. # 5. # 6. # 6. # 13. # 0. # 6. # 6. # 5. # 4. # 12. # 10. # 5. # 7. # 1. # 9. # 12. # 9. # 3. # 7. # 8. # 5. # 12. # 8. # 5. # 8. # 1. # 11. # 12. # 7. # 11. # 11. # 6. # 6. # 4. # 4. # 45. <lb/>50. # 4. # 6. # 1. # 14. # 6. # 1. # 5. # 10. # 9. # 14. # 2. # 9. # 6. # 11. # 3. # 14. # 0. # 11. # 7. # 8. # 4. # 13. # 11. # 4. # 8. # 4. # 1. # 13. # 10. # 9. # 8. # 9. # 6. # 13. # 9. # 6. # 12. # 7. # 0. # 4. # 8. # 50. <lb/>55. # 4. # 8. # 4. # 15. # 8. # 4. # 6. # 2. # 9. # 15. # 4. # 9. # 7. # 4. # 2. # 15. # 2. # 5. # 8. # 2. # 4. # 15. # 0. # 10. # 8. # 11. # 7. # 14. # 11. # 11. # 9. # 5. # 2. # 14. # 11. # 2. # 13. # 7. # 6. # 5. # 0. # 55. <lb/>60. # 4. # 10. # 2. # 16. # 10. # 2. # 6. # 6. # 11. # 16. # 9. # 11. # 7. # 9. # 1. # 16. # 3. # 11. # 8. # 8. # 1. # 16. # 2. # 1. # 9. # 5. # 0. # 16. # 1. # 0. # 10. # 0. # 4. # 16. # 0. # 4. # 14. # 8. # 0. # 5. # 4. # 60. <lb/>65. # 4. # 11. # 9. # 17. # 11. # 9. # 6. # 9. # 11. # 17. # 7. # 11. # 8. # 1. # 9. # 17. # 4. # 2. # 9. # 1. # 10. # 17. # 3. # 4. # 9. # 10. # 8. # 17. # 1. # 4. # 10. # 6. # 5. # 17. # 0. # 5. # 15. # 8. # 6. # 5. # 8. # 65. <lb/>70. # 5. # 1. # 9. # 19. # 1. # 9. # 7. # 9. # 6. # 18. # 9. # 6. # 8. # 4. # 5. # 18. # 4. # 5. # 9. # 5. # 6. # 18. # 2. # 6. # 10. # 4. # 8. # 18. # 2. # 0. # 11. # 0. # 4. # 17. # 11. # 4. # 16. # 9. # 0. # 6. # 0. # 70. <lb/>75. # 5. # 2. # 2. # 20. # 2. # 2. # 7. # 3. # 9. # 19. # 9. # 9. # 8. # 7. # 6. # 19. # 4. # 0. # 9. # 8. # 7. # 19. # 1. # 1. # 10. # 8. # 0. # 19. # 0. # 0. # 11. # 6. # 0. # 18. # 11. # 11. # 17. # 9. # 6. # 6. # 4. # 75. <lb/>80. # 5. # 3. # 4. # 21. # 3. # 4. # 7. # 5. # 5. # 20. # 9. # 5. # 8. # 10. # 1. # 20. # 3. # 2. # 9. # 11. # 0. # 19. # 11. # 6. # 10. # 11. # 6. # 19. # 10. # 2. # 11. # 11. # 4. # 19. # 10. # 0. # 18. # 10. # 0. # 6. # 8. # 80. <lb/>85. # 5. # 4. # 7. # 22. # 4. # 7. # 7. # 6. # 9. # 21. # 8. # 9. # 8. # 11. # 6. # 21. # 0. # 2. # 10. # 1. # 6. # 20. # 9. # 0. # 11. # 2. # 0. # 20. # 7. # 4. # 12. # 4. # 0. # 20. # 5. # 0. # 19. # 10. # 6. # 7. # 0. # 85. <lb/>90. # 5. # 5. # 6. # 23. # 5. # 6. # 7. # 7. # 4. # 22. # 7. # 4. # 9. # 1. # 8. # 21. # 11. # 11. # 10. # 3. # 8. # 21. # 8. # 8. # 11. # 4. # 10. # 21. # 4. # 10. # 12. # 7. # 6. # 21. # 4. # 6. # 20. # 11. # 0. # 7. # 4. # 90. <lb/>95. # 5. # 5. # 9. # 24. # 5. # 9. # 7. # 8. # 6. # 23. # 6. # 6. # 9. # 3. # 6. # 22. # 10. # 4. # 10. # 5. # 4. # 22. # 3. # 10. # 11. # 6. # 4. # 22. # 1. # 0. # 12. # 10. # 2. # 22. # 0. # 2. # 21. # 11. # 6. # 7. # 8. # 95. <lb/>100. # 5. # 6. # 6. # 25. # 6. # 6. # 7. # 9. # 7. # 24. # 5. # 7. # 9. # 4. # 9. # 23. # 8. # 2. # 10. # 7. # 0. # 23. # 1. # 0. # 11. # 8. # 0. # 22. # 9. # 4. # 13. # 0. # 9. # 22. # 8. # 9. # 22. # 12. # 0. # 8. # 0. # 100. <lb/></note> <pb file="0264" n="274"/> <pb o="79" file="0265" n="275" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> <p> <s xml:id="echoid-s5694" xml:space="preserve">voit d’abord intrigué: mais après en avoir aperçu la raiſon, j’aire- gardé ce changement comme une preuve de la juſteſſe du principe, plûtôt que de la part des fautes qui auroient pû ſe gliſſer dans les calculs; voilà l’avantage des Mathematiques, qui eſt de voir toû- jours clair à ce que l’on fait.</s> </p> </div> <div xml:id="echoid-div286" type="section" level="2" n="88"> <head xml:id="echoid-head226" xml:space="preserve">CHAPITRE ONZIE’ME.</head> <head xml:id="echoid-head227" style="it" xml:space="preserve">De la conſtruction des Souterrains, & comme l’on aplique <lb/>ſur leurs Voûtes les Chapes de Ciment.</head> <p> <s xml:id="echoid-s5695" xml:space="preserve">L’On entend par ſouterrain, tous les lieux voutés qui ſe prati-<lb/>quent ſous les rempars d’une place, comme les poternes qui <lb/>ſervent à communiquer dans les ouvrages detachés, les Magaſins <lb/>que l’on peut placer dans les tours, les lieux que l’on fait à l’épreu-<lb/>ve de la bombe, pour ſervir de refuge en tems de ſiége.</s> <s xml:id="echoid-s5696" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5697" xml:space="preserve">Les ſouterrains ſont d’un grand ſecours dans les petites Forte-<lb/>reſſes, Citadelles, Forts, & </s> <s xml:id="echoid-s5698" xml:space="preserve">Châteaux, où il n’ya pas d’endroit qui <lb/>ne ſoit expoſé à être detruit en très peu de tems; </s> <s xml:id="echoid-s5699" xml:space="preserve">au lieu que dans <lb/>les grandes places, on a toûjours quelque quartier éloigné des <lb/>attaques; </s> <s xml:id="echoid-s5700" xml:space="preserve">où l’on peut mettre les munitions de guerre, de bou-<lb/>che, & </s> <s xml:id="echoid-s5701" xml:space="preserve">même les malades & </s> <s xml:id="echoid-s5702" xml:space="preserve">bleſſés.</s> <s xml:id="echoid-s5703" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5704" xml:space="preserve">Mais avant de parler de la diſtribution des ſouterrains, il eſt à pro-<lb/>pos de dire quelque choſe ſur la maniere de les conſtruire, car il <lb/>ne ſuffit pas de les rendre à l’épreuve de la bombe, il faut les met-<lb/>tre auſſi à l’abri des injures du tems, & </s> <s xml:id="echoid-s5705" xml:space="preserve">le plus qu’il eſt poſſible <lb/>de l’humidité: </s> <s xml:id="echoid-s5706" xml:space="preserve">pour cela, l’on aplique ſur leurs voutes des chapes <lb/>de ciment, dont voici la fabrique.</s> <s xml:id="echoid-s5707" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5708" xml:space="preserve">Le ciment à cet uſage ſe’fait ordinairement avec de la cendrée <lb/>de Tournai, battuë & </s> <s xml:id="echoid-s5709" xml:space="preserve">preparée tous les quatre ou cinq jours une <lb/>fois pendant ſix ſemaines, obſervant de n’y mettre de l’eau que <lb/>la premiere fois; </s> <s xml:id="echoid-s5710" xml:space="preserve">ou bien l’on prend un tiers de bonne chaux vive <lb/>ſur deux tiers de terraſſe de Hollande, que l’on bat & </s> <s xml:id="echoid-s5711" xml:space="preserve">prepare de <lb/>même; </s> <s xml:id="echoid-s5712" xml:space="preserve">& </s> <s xml:id="echoid-s5713" xml:space="preserve">au lieu de terraſſe de Hollande, on met, ſi l’on veut, les <lb/>deux tiers de pozzolane ou de vieux tuilleauxbien cuits, reduits en <lb/>farine, repaſſés au tamis de Boulanger; </s> <s xml:id="echoid-s5714" xml:space="preserve">mais ſoit qu’on ſe ſerve de <lb/>l’un ou de l’autre de ces cimens, il faut les bien reduire en farine <lb/>avec un moulin à bras, enſuite battre enſemble les deux matie-<lb/>res qui le compoſent, & </s> <s xml:id="echoid-s5715" xml:space="preserve">les mêler un long eſpace de tems dans <pb o="80" file="0266" n="276" rhead="LA SCIENCE DES INGENIEURS,"/> des petits bacquets de planche faits exprès; </s> <s xml:id="echoid-s5716" xml:space="preserve">ce mélange doit ſe fai-<lb/>re à pluſieurs repriſes, ſans y mettre de l’eau que la premiere <lb/>fois.</s> <s xml:id="echoid-s5717" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5718" xml:space="preserve">Avant d’apliquer le ciment ſur les voutes, il eſt neceſſaire que <lb/>la maçonnerie ſoit bien achevée, & </s> <s xml:id="echoid-s5719" xml:space="preserve">qu’elle ait eu au moins cinq <lb/>ou ſix mois de tems pour ſecher & </s> <s xml:id="echoid-s5720" xml:space="preserve">prendre ſes affaiſſemens, l’on en <lb/>grate & </s> <s xml:id="echoid-s5721" xml:space="preserve">foüille les joints avec un petit crochet de fer, après quoi <lb/>on nétoye bien le deſſus, que l’on arroſe en y jettant de l’eau avec <lb/>un arroſoir, puis l’on aplique le ciment tout fraichement demêlé, <lb/>de l’épaiſſeur d’un pouce & </s> <s xml:id="echoid-s5722" xml:space="preserve">demi, qu’on étend bien également, on <lb/>le bat de long & </s> <s xml:id="echoid-s5723" xml:space="preserve">de large, avec de petites battes de deux pouces <lb/>de largeur ſeulement, pour mieux preſſer le ciment dans les joints, <lb/>enſuite avec des fers polis, comme ceux dont on ſe ſert pour re-<lb/>paſſer le linge, & </s> <s xml:id="echoid-s5724" xml:space="preserve">retrouſſés par les bouts en adouciſſant, l’on rend <lb/>la premiere couche unie juſqu’à ce qu’elle commence à s’affermir, <lb/>on broüille tous les jours pendant un tems ſa ſuperficie, avec un <lb/>torchon de drap, gros comme la tête, emmenché au bout d’un bâ-<lb/>ton, & </s> <s xml:id="echoid-s5725" xml:space="preserve">trempé dans un ſeau de ciment delayé, on paſſe auſſi-tôt le <lb/>liſſoir deſſus, après cela on couvre tout le couchi avec des paillaſſons, <lb/>juſqu’au lendemain, afin que les chaleurs ne le faſſent point gerſer, <lb/>l’on repete cette manœuvre, c’eſt-à-dire, l’on broüille, on liſſe, <lb/>& </s> <s xml:id="echoid-s5726" xml:space="preserve">on recouvre, tant qu’on s’aperçoive qu’il n’y a plus de gerſure <lb/>dans la ſuperficie; </s> <s xml:id="echoid-s5727" xml:space="preserve">cela fait on broüille encore pendant cinq ou ſix <lb/>jours de ſuite ſans liſſer, ni paillaſſonner.</s> <s xml:id="echoid-s5728" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5729" xml:space="preserve">En appliquant les chapes de ciment, on aura ſoin ſur toute cho-<lb/>ſe de les rendre bien unies, & </s> <s xml:id="echoid-s5730" xml:space="preserve">de terminer le ſommet des voutes <lb/>en dos d’âne, avec des pentes dirigées comme celle des toits; </s> <s xml:id="echoid-s5731" xml:space="preserve">en <lb/>conſtruiſant la voute, l’on fera enſorte qu’elle ſoit également cein-<lb/>trée, & </s> <s xml:id="echoid-s5732" xml:space="preserve">bandée ſur le ceintre, ne ſe ſervant que de mortier choi-<lb/>ſi, & </s> <s xml:id="echoid-s5733" xml:space="preserve">que la pierre qu’on mettra en œuvre ſoit bien apareillée: </s> <s xml:id="echoid-s5734" xml:space="preserve">ſi <lb/>au lieu de pierre l’on employe de la brique, on choiſira la mieux <lb/>cuite, dont on fera quatre ou cinq voutes repetées l’une ſur l’au-<lb/>tre, & </s> <s xml:id="echoid-s5735" xml:space="preserve">chacune d’elles bandée, & </s> <s xml:id="echoid-s5736" xml:space="preserve">bien fichée de coins ſous les clefs <lb/>ſeparément, & </s> <s xml:id="echoid-s5737" xml:space="preserve">lors qu’on apliquera les chapes de ciment, l’on pren-<lb/>dra bien garde qu’elles couvrent toutes les parties de la maçonne-<lb/>rie, de façon qu’aucune pierre ne ſe montre au travers, on cou-<lb/>vre enſuite la chape de ciment, d’un lit de gros ſable ou gravier, <lb/>de quatre à cinq pouces d’épais, qu’on étend également par tout; <lb/></s> <s xml:id="echoid-s5738" xml:space="preserve">ſur celui-ci on en met un autre de terre, d’un pied & </s> <s xml:id="echoid-s5739" xml:space="preserve">demi bien <lb/>battu, & </s> <s xml:id="echoid-s5740" xml:space="preserve">on continue demême de lit enlit, juſqu’au parfait terraſſe-<lb/>ment: </s> <s xml:id="echoid-s5741" xml:space="preserve">c’eſt ainſi qu’on en a uſé pour couvrir les voutes des tours <pb o="81" file="0267" n="277" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUK."/> baſtionnées du neuf Briſack, comme on le verra dans le 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5742" xml:space="preserve">Livre.</s> <s xml:id="echoid-s5743" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5744" xml:space="preserve">Autrefois, quand on faiſoit des Voûtes de Briques, on les com-<lb/>poſoit comme je le viens de dire de pluſieurs Voûtes l’une ſur l’au-<lb/>tre qui avoient chacune une brique d’épaiſſeur, ſans faire enſemble <lb/>aucune liaiſon; </s> <s xml:id="echoid-s5745" xml:space="preserve">mais on a reconnu depuis que cette pratique ne va-<lb/>loit rien, qu’il convenoit beaucoup mieux de les faire en liaiſon al-<lb/>ternative depuis l’intrados juſqu’à l’extrados, ſans aucune interrup-<lb/>tion, ayant beaucoup plus de force pour réſiſter au choc des Bom-<lb/>bes. </s> <s xml:id="echoid-s5746" xml:space="preserve">L’inconvenient des Voûtes repetées l’une ſur l’autre, c’eſt que <lb/>s’il ſe fait quelque écorchement à la premiere, auſſi-tôt qu’il vient <lb/>à ſe détacher deux ou trois briques, toutes les autres ſe ſéparent <lb/>de ſuite; </s> <s xml:id="echoid-s5747" xml:space="preserve">ce qui rend les réparations très difficiles, parce qu’on ne <lb/>trouve point d’amorce pour lier la nouvelle Maçonnerie avec la <lb/>vieille: </s> <s xml:id="echoid-s5748" xml:space="preserve">l’on a même vû pluſieurs fois la premiere Voûte ſoufler & </s> <s xml:id="echoid-s5749" xml:space="preserve"><lb/>ſe détacher entierement de la ſeconde, peu de tems après la conſ-<lb/>truction de l’ouvrage.</s> <s xml:id="echoid-s5750" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5751" xml:space="preserve">A l’occaſion des ſouterrains, je raporterai ici ce qui a été ob-<lb/>ſervé dans la conſtruction de la fameuſe Orangerie de Verſailles, <lb/>afin qu’en pareil cas, on puiſſe, ſi on le juge à propos, ſuivre ce <lb/>que l’on a fait pour mettre cet édifice à l’abri des injures du tems.</s> <s xml:id="echoid-s5752" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5753" xml:space="preserve">Auſſi-tôt que la voute fut formée, on netoya proprement le <lb/>deſſus des reins, au bas deſquels on commença un lit de pierre <lb/>ou de moilon à ſec de 18. </s> <s xml:id="echoid-s5754" xml:space="preserve">pouces de hauteur, avec de la pouſ-<lb/>ſiere de chaux, entre leurs joints, enſuite on a mis au deſſus un lit <lb/>auſſi de pouſſiere de chaux, de 4. </s> <s xml:id="echoid-s5755" xml:space="preserve">pouces d’épaiſſeur, & </s> <s xml:id="echoid-s5756" xml:space="preserve">ſur celui-<lb/>ci on en fit un troiſiéme de cailloux de vignes, & </s> <s xml:id="echoid-s5757" xml:space="preserve">de galets bien la-<lb/>vés, de 12. </s> <s xml:id="echoid-s5758" xml:space="preserve">pouces d’épaiſſeur, ſur lequel on en mit derechef un <lb/>quatriéme de pouſſiere de chaux, toûjours de 4. </s> <s xml:id="echoid-s5759" xml:space="preserve">pouces, & </s> <s xml:id="echoid-s5760" xml:space="preserve">par <lb/>deſſus un cinquiéme de galets, & </s> <s xml:id="echoid-s5761" xml:space="preserve">ainſi juſqu’au niveau du ſommet <lb/>de la voute, ſur laquelle on a poſé un dernier lit de galets, de 12. <lb/></s> <s xml:id="echoid-s5762" xml:space="preserve">pouces, recouvert d’une couche de mortier, qui occupe tout l’eſ-<lb/>pace de deſſus, juſqu’au delà même des pieds droits; </s> <s xml:id="echoid-s5763" xml:space="preserve">l’on s’eſt ſi <lb/>bien trouvé de cette fabrique, que, quoique le deſſus de cette Oran-<lb/>gerie ne ſoit qu’une terraſſe, il n’eſt arrivé aucun dommage à <lb/>la voute.</s> <s xml:id="echoid-s5764" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5765" xml:space="preserve">On ſuit encore une pratique qui differe un peu de la précédente: <lb/></s> <s xml:id="echoid-s5766" xml:space="preserve">c’eſt qu’après avoir mis ſur la voute un lit de pierre ſeche, dont les <lb/>joints ſont remplis de pouſiere de chaux, & </s> <s xml:id="echoid-s5767" xml:space="preserve">en avoir repandu par <lb/>deſſus environ quatre pouces d’épaiſſeur, on met un lit de terre <lb/>glaiſe, de 12. </s> <s xml:id="echoid-s5768" xml:space="preserve">pouces bien battuë, qu’on couvre d’un autre lit de <lb/>galets auſſi de 12. </s> <s xml:id="echoid-s5769" xml:space="preserve">pouces, entremêlés de pouſſiere de chaux, ſur <pb o="82" file="0268" n="278" rhead="LA SCIENCE DES INGENIEURS,"/> lequel on en met un dernier de mortier, de trois à quatre pouces <lb/>d’épaiſſeur, pour recevoir les terres.</s> <s xml:id="echoid-s5770" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5771" xml:space="preserve">Les voutes des ſouterrains, pour être à l’épreuve de la bombe, <lb/>doivent avoir au moins trois pieds d’épaiſſeur, recouvertes par cinq <lb/>ou ſix pieds de terre; </s> <s xml:id="echoid-s5772" xml:space="preserve">quant à la figure qu’elles doivent avoir, cel-<lb/>le à plein ceintre eſt la meilleure pour les raiſons raportées dans le <lb/>ſecond Livre.</s> <s xml:id="echoid-s5773" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5774" xml:space="preserve">Les ſouterrains ſe placent ordinairement ſous le terre-plain des <lb/>Baſtions, parce que là on peut leur donner plus d’étenduë que ſous <lb/>la courtine, qui n’a point tant de largeur; </s> <s xml:id="echoid-s5775" xml:space="preserve">mais, en quelque en-<lb/>droit qu’on veuille les placer, il faut faire enſorte d’en tirer toutes <lb/>les commodités poſſibles, afin qu’ils puiſſent ſervir à pluſieurs uſa-<lb/>ges, par exemple, on peut y faire des fours, des citernes, & </s> <s xml:id="echoid-s5776" xml:space="preserve">des <lb/>cheminées, pour ſen ſervir au beſoin.</s> <s xml:id="echoid-s5777" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5778" xml:space="preserve">Si l’on jette les yeux ſur la figure 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5779" xml:space="preserve">de la planche 11<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5780" xml:space="preserve">l’on ver-<lb/> <anchor type="note" xlink:label="note-0268-01a" xlink:href="note-0268-01"/> ra des ſouterrains, qui ſont pratiqués ſous un cavalier, qui occu-<lb/>pent le terre-plain d’un Baſtion, l’on remarquera que leur diſtribu-<lb/>tion eſt diſpoſée de maniere, qu’on peut y faire des boulangeries, <lb/>pour cuire le pain de la garniſon, des cuiſines, des celliers, enfin <lb/>tous autres lieux propres à mettre à couvert des munitions.</s> <s xml:id="echoid-s5781" xml:space="preserve"/> </p> <div xml:id="echoid-div286" type="float" level="3" n="1"> <note position="left" xlink:label="note-0268-01" xlink:href="note-0268-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>11.</note> </div> <p> <s xml:id="echoid-s5782" xml:space="preserve">La figure 5<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5783" xml:space="preserve">eſt un profil coupé ſur la largeur des ſouterrains, <lb/>qui fait voir la diſpoſition des chapes de ciment ſur les voutes, & </s> <s xml:id="echoid-s5784" xml:space="preserve"><lb/>comme les tuyaux des cheminées paſſent dans le parapet du cava-<lb/>lier, pour ne ponit incommoder le ſervice du canon. </s> <s xml:id="echoid-s5785" xml:space="preserve">Par la figu-<lb/>re 4<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5786" xml:space="preserve">l’on verra le profil des mêmes ſouterrains, coupé ſur la ca-<lb/>pitale du Baſtion, où l’on remarquera qu’on a menagé des portes <lb/>au ſouterrain du milieu, pour communiquer dans les deux autres <lb/>voiſins.</s> <s xml:id="echoid-s5787" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5788" xml:space="preserve">Quand les chapes de ciment ſont apliquées ſur des voutes, au <lb/>deſſus deſquelles il y a des plateformes, il faut au lieu de terminer <lb/>la chape à l’extremité des pentes, la retrouſſer contre la muraille, <lb/>afin que les eaux de pluye ne puiſſent point s’introduire ſur la <lb/>voute; </s> <s xml:id="echoid-s5789" xml:space="preserve">pour leur donner un écoulement, on fera une rigole, qui, <lb/>regnant tout autour de la plateforme, conduira les eaux dans des <lb/>gargoüilles, qui les porteront dans le foſſé.</s> <s xml:id="echoid-s5790" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5791" xml:space="preserve">Pour garantir les pieds droits des voutes des ſouterrains, des eaux <lb/>qui filtrent dans les terres, il faut leur adoſſer un petit mur de pier-<lb/>res ſeches, de deux pieds d’épaiſſeur, c’eſt-à-dire, arragées à la <lb/>main ſans mortier, les joints remplis de gravier; </s> <s xml:id="echoid-s5792" xml:space="preserve">ces murs doivent <lb/>être élevés juſqu’à deux pieds au-deſſous des pentes de la voute, <lb/>afin de remplir cet intervalle de bonne maçonnerie, à chaux & </s> <s xml:id="echoid-s5793" xml:space="preserve">à <pb file="0269" n="279"/> <pb file="0269a" n="280"/> <anchor type="figure" xlink:label="fig-0269a-01a" xlink:href="fig-0269a-01"/> <pb file="0270" n="281"/> <pb o="83" file="0271" n="282" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> ſable, bien recouverte par le prolognement de la chape de ciment, <lb/>qui regnant ſur toute l’épaiſſeur de ces petits murs, mettra les <lb/>pieds droits à l’abri de la tranſpiration, & </s> <s xml:id="echoid-s5794" xml:space="preserve">de l’humidité: </s> <s xml:id="echoid-s5795" xml:space="preserve">pour bien <lb/>faire il faut fonder ces pierrées deux pieds plus bas que l’aire des <lb/>ſouterrains, afin d’y pratiquer des conduits, dans le milieu de la <lb/>fondation, pour l’égout des eaux.</s> <s xml:id="echoid-s5796" xml:space="preserve"/> </p> <div xml:id="echoid-div287" type="float" level="3" n="2"> <figure xlink:label="fig-0269a-01" xlink:href="fig-0269a-01a"> <image file="0269a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0269a-01"/> </figure> </div> <p> <s xml:id="echoid-s5797" xml:space="preserve">Il me reſte à parler des Poternes, ſur leſquelles il n’y a pas grand <lb/>choſe à dire, parce que leur conſtruction eſt la même que celle <lb/>des autres ſouterrains; </s> <s xml:id="echoid-s5798" xml:space="preserve">on les place dans le milieu des courtines, <lb/>quelquefois derriere les orillons, pour communiquer dans la tenail-<lb/>le, ou dans le foſſé quand il eſt à ſec; </s> <s xml:id="echoid-s5799" xml:space="preserve">mais plus ordinairement dans <lb/>le milieu des courtines, pour aller droit à la demi-lune. </s> <s xml:id="echoid-s5800" xml:space="preserve">Si l’on <lb/>conſidere les figures premiere, ſeconde, & </s> <s xml:id="echoid-s5801" xml:space="preserve">troiſiéme, l’on verra qu’el-<lb/>les repreſentent les plans & </s> <s xml:id="echoid-s5802" xml:space="preserve">profils d’une poterne, que je ne m’arre-<lb/>terai point à détailler, parce qu’il en ſera fait mention dansle 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5803" xml:space="preserve">Li-<lb/>vre: </s> <s xml:id="echoid-s5804" xml:space="preserve">on remarquera ſeulement que dans le tems qu’on les conſ-<lb/>truit, il eſt à propos de faire au deſſous de leur rez-de-Chauſſée, <lb/>un petit acqueduc pour ſervir d’égout aux eaux des ruës, & </s> <s xml:id="echoid-s5805" xml:space="preserve">les <lb/>conduire dans le foſſé.</s> <s xml:id="echoid-s5806" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5807" xml:space="preserve">J’ai penſé pluſieurs fois, à l’occaſion des poternes, qu’on pou-<lb/>voit, à droit & </s> <s xml:id="echoid-s5808" xml:space="preserve">à gauche du paſſage, pratiquer ſous la courtine <lb/>deux petits magaſins, qui ſeroient d’une grande utilité en tems de <lb/>ſiége, pour ſervir d’entrepots aux munitions qu’on voudroit avoir à <lb/>portée des ouvrages detachés, & </s> <s xml:id="echoid-s5809" xml:space="preserve">à pluſieurs autres uſages, dont <lb/>ceux qui ſe ſont trouvés dans des places aſſiegées, ſentiront aſſés la <lb/>conſequence: </s> <s xml:id="echoid-s5810" xml:space="preserve">ſi l’on jette les yeux ſur la figure 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5811" xml:space="preserve">l’on verra aſſez <lb/>clairement quel eſt mon deſſein, ſans qu’il ſoit beſoin d’une plus <lb/>longue explication: </s> <s xml:id="echoid-s5812" xml:space="preserve">je dirai ſeulement que la poterne qu’elle re-<lb/>preſente eſt ſupoſée en rempe, ſans aucun degré.</s> <s xml:id="echoid-s5813" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5814" xml:space="preserve">J’aurois pû raporter encore pluſieurs autres diſtributions de ſou-<lb/>terrains, car la plûpart de nos places nous en fourniſſent d’aſſés <lb/>magnifiques, pour ne pas manquer de bons modeles: </s> <s xml:id="echoid-s5815" xml:space="preserve">mais comme <lb/>l’application qu’on en fait depend des lieux, de la diſpoſition des ou-<lb/>vrages, & </s> <s xml:id="echoid-s5816" xml:space="preserve">de quantité de circonſtances que la ſeule neceſſité fait <lb/>bien diriger; </s> <s xml:id="echoid-s5817" xml:space="preserve">j’ai crû devoir m’en tenir à l’idée que je viens de <lb/>donner, qui ſuffira à de jeunes Ingenieurs, pour les mettre en état <lb/>d’executer les projets de ces ſortes d’ouvrages, pour peu qu’ils <lb/>ſoient aidés par les devis, plans, profils, & </s> <s xml:id="echoid-s5818" xml:space="preserve">inſtructions particulie-<lb/>res, que les chefs ont coûtume de leur donner en pareil cas.</s> <s xml:id="echoid-s5819" xml:space="preserve"/> </p> <pb o="84" file="0272" n="283" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div289" type="section" level="2" n="89"> <head xml:id="echoid-head228" xml:space="preserve">CHAPITRE DOUZIE’ME. <lb/>De la maniere de conſtruire les Ouvrages de Terraſſes.</head> <p> <s xml:id="echoid-s5820" xml:space="preserve">AMeſure que l’on éleve le revêtement d’un ouvrage, l’on fait <lb/>le remblais des terres pour former le rempart. </s> <s xml:id="echoid-s5821" xml:space="preserve">On commence <lb/>par égaliſer le fond du terrain qui répond à la derniere retraite du <lb/>côté de la place, en lui donnant une pente d’environ trois pouces <lb/>par toiſe du devant au derriere, afin de ſoulager le revêtement; </s> <s xml:id="echoid-s5822" xml:space="preserve">car <lb/>nous ſupoſons que cet eſpace eſt bien deblayé, & </s> <s xml:id="echoid-s5823" xml:space="preserve">n’eſt pas occupé <lb/>par les terres qu’on a tirées du foſſé pour former les remparts, c’eſt <lb/>ce qui nous a fait dire dans le 8<emph style="sub">e</emph>. </s> <s xml:id="echoid-s5824" xml:space="preserve">Chapitre qu’il falloit les porter <lb/>à 8 ou 10 toiſes au-delà de l’allignement interieur de la muraille, <lb/>afin qu’on ne ſoit pas obligé de les rejetter plus loin, mais placées <lb/>de façon que les travailleurs, les ayant ſous la main pour faire les <lb/>remblais, l’on poſe un lit de faſcinage, dont le gros bout eſt du côté <lb/>de la muraille, les brins eſpacés de 4 à 5 pouces les uns des autres: <lb/></s> <s xml:id="echoid-s5825" xml:space="preserve">les faſcines doivent avoir au moins 12 pieds de longueur, & </s> <s xml:id="echoid-s5826" xml:space="preserve">3 ou 4 <lb/>pouces de circonference par le gros bout, on les recouvre d’un <lb/>lit de terre d’environ 8 pouces de hauteur que l’on bat à la Dame <lb/>tant qu’il ſoit réduit à ſix; </s> <s xml:id="echoid-s5827" xml:space="preserve">on répete un ſecond & </s> <s xml:id="echoid-s5828" xml:space="preserve">un troiſiéme lit <lb/>de terre toûjours de 8 pouces bien batus & </s> <s xml:id="echoid-s5829" xml:space="preserve">chacun réduit à ſix pou-<lb/>ces. </s> <s xml:id="echoid-s5830" xml:space="preserve">S’il ſerencontre des pierres qui empêchent qu’on ne puiſſe bat-<lb/>tre également par-tout, on les ôte pour les mettre de côté, enſuite <lb/>on étend ſur ce troiſiéme tas un ſecond lit de faſcinage diſpoſé com-<lb/>me le premier, que l’on couvre encore de trois autres tas de terre <lb/>de 8 pouces, chacun batus ſéparement & </s> <s xml:id="echoid-s5831" xml:space="preserve">réduits à 6 que l’on re-<lb/>couvre encore d’un lit de faſcinage, ainſi de ſuite alternativement <lb/>trois tas de terres, & </s> <s xml:id="echoid-s5832" xml:space="preserve">un lit de faſcinage juſqu’à la hauteur du terre-<lb/>plain du rempart auquel on donne une pente d’un pied & </s> <s xml:id="echoid-s5833" xml:space="preserve">demi de-<lb/>puis la banquette juſqu’au talud interieur, en obſervant d’en faire <lb/>la ſurface d’une terre bien épierrée & </s> <s xml:id="echoid-s5834" xml:space="preserve">battuë ſi uniment que les eaux <lb/>de pluye coulent ſans difficulté; </s> <s xml:id="echoid-s5835" xml:space="preserve">après quoi on éleve le parapet qui <lb/>ſe conſtruit de même que le rempart; </s> <s xml:id="echoid-s5836" xml:space="preserve">mais avec un peu plus de <lb/>précaution: </s> <s xml:id="echoid-s5837" xml:space="preserve">car ſi les terres dont on veut ſe ſervir ſont pierreuſes, <lb/>on les paſſe à la claye, ou bien on en choiſit de douce, & </s> <s xml:id="echoid-s5838" xml:space="preserve">de celle <lb/>qui convient le mieux.</s> <s xml:id="echoid-s5839" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5840" xml:space="preserve">O’eſt ainſi qu’on a coûtume de travailler les ouvrages de terraſſe <pb o="85" file="0273" n="284" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> en les mêlant avec des lits de faſcinage que je ne voudrois pourtant <lb/>employer qu’à la derniere extrêmité quand on a des terres boüeu-<lb/>ſes ou ſabloneuſes qui n’ont point de cervelle, encore ne devroit-<lb/>on s’en ſervir que lorſqu’on fait des ouvrages qui ne ſont revêtus <lb/>que de gaſons; </s> <s xml:id="echoid-s5841" xml:space="preserve">car pour ceux qui ſont ſoûtenus par une bonne mu-<lb/>raille, je croi qu’avec un peu de précaution on pourroit s’en paſſer: <lb/></s> <s xml:id="echoid-s5842" xml:space="preserve">leur deffaut eſt qu’étant nouvellement poſées elles empêchent par <lb/>leur reſſort qu’on puiſſe battre les terres auſſi ſolidement qu’on le <lb/>feroit s’il n’y en avoit point, & </s> <s xml:id="echoid-s5843" xml:space="preserve">que venant à ſe pourrir au bout d’un <lb/>certain tems elles laiſſent beaucoup de vuide, ce qui fait que les <lb/>terres s’affaiſſent tout denouveau & </s> <s xml:id="echoid-s5844" xml:space="preserve">ſe réduiſent à unehauteur beau-<lb/>coup au-deſſous de celle qui avoit été reglée par les profils.</s> <s xml:id="echoid-s5845" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5846" xml:space="preserve">Pour ſe paſſer de faſcines dans la conſtruction des Ouvrages re-<lb/>vêtus, je voudrois que les remblais ſuiviſſent exactement le progrés <lb/>de la Maçonnerie, s’il s’agit d’un ouvrage qui ait pluſieurs côtés, <lb/>après avoir élevé la Maçonnerie d’une face de Baſtion, par exem-<lb/>ple à une certaine hauteur qui ſera ſi l’on veut de deux pieds, les <lb/>Maçons la quitteront pour aller faire une pareille levée à l’autre <lb/>face ou au flanc voiſin, & </s> <s xml:id="echoid-s5847" xml:space="preserve">les Terraſſiers viendront s’emparer de <lb/>celle qui eſt vacante pour faire les remblais à la hauteur où ſe trouve <lb/>la Maçonnerie, obſervant de bien battre les terres lit par lit de 8 <lb/>pouces en 8 pouces, toûjours réduites à 6, enſuite les Maçons re-<lb/>viendront à la partie qu’ils avoient abandonnée pour y faire une <lb/>deuxiéme levée de deux pieds, tandis que les Terraſſiers occupe-<lb/>ront celle que viennent de quitter les Maçons, deſorte que pour <lb/>bien faire il faut que les Maçons & </s> <s xml:id="echoid-s5848" xml:space="preserve">les Terraſſiers ſe ſuccedent al-<lb/>ternativement. </s> <s xml:id="echoid-s5849" xml:space="preserve">De cette conduite, il arrivera deux choſes également <lb/>avantageuſes; </s> <s xml:id="echoid-s5850" xml:space="preserve">la premiere, c’eſt que les Maçons auront toûjours un <lb/>emplacement commode pour y travailler à leur aiſe, par conſequent <lb/>feront un meilleur ouvrage; </s> <s xml:id="echoid-s5851" xml:space="preserve">la ſeconde c’eſt qu’en jettant ſur les <lb/>terres nouvellement battuës, les materiaux qu’ils doivent employer <lb/>à leur nouvelle levée, & </s> <s xml:id="echoid-s5852" xml:space="preserve">les piétinemens continuels de tous ceux <lb/>qui ſeront employés à la Maçonnerie, battront les terres incom-<lb/>parablement mieux qu’elles ne l’avoient été d’abord; </s> <s xml:id="echoid-s5853" xml:space="preserve">ce qui leur fera <lb/>prendre tout l’affaiſſement auquel elle ne ſeroient arrivées que long-<lb/>tems après l’ouvrage achevé.</s> <s xml:id="echoid-s5854" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5855" xml:space="preserve">Ce qui demande encore beaucoup d’attention dans la conſtruc-<lb/>tion des ouvrages de terraſſe, ce ſont les revêtemens de placage <lb/>ou de gaſon. </s> <s xml:id="echoid-s5856" xml:space="preserve">Le placage ſe fait avec de la terre noire non pierreuſe, <lb/>qui ne doit être, ni trop graſſe, ni trop maigre, mais participante <lb/>des deux, afin qu’elle ne ſe fende ni ne ſe renfle point après qu’elle <pb o="86" file="0274" n="285" rhead="LA SCIENCE DES INGENIEURS,"/> aura été employée. </s> <s xml:id="echoid-s5857" xml:space="preserve">On commence par creuſer une petite tranchéc <lb/>au pied du parapet pour ſervir comme de fondement au reſte de <lb/>l’ouvrage, on la remplit de la terre ſervant au placage, & </s> <s xml:id="echoid-s5858" xml:space="preserve">on a ſoin <lb/>de la moüiller & </s> <s xml:id="echoid-s5859" xml:space="preserve">de la lier avec celle qui compoſe le parapet: </s> <s xml:id="echoid-s5860" xml:space="preserve">après <lb/>l’avoir bien battuë, on étend deſſus un lit de chiendent fraîchement <lb/>tiré pour reprendre plus aiſément, enſuite l’on applique le premier <lb/>tas; </s> <s xml:id="echoid-s5861" xml:space="preserve">c’eſt-à-dire un premier lit de terre noire auquel on donne 12 <lb/>pouces d’épaiſſeur ſur 6 de hauteur que l’on bat bien en long & </s> <s xml:id="echoid-s5862" xml:space="preserve">en <lb/>large, juſqu’à ce qu’il ſoit réduit à n’en avoir plus que 4, on recou-<lb/>vre ce lit d’un autre de chiendent mêlé avec de la petite faſcine: <lb/></s> <s xml:id="echoid-s5863" xml:space="preserve">ſur ce tas ci, on en aplique un autre battu & </s> <s xml:id="echoid-s5864" xml:space="preserve">bien lié avec les terres <lb/>du parapet que l’on bat & </s> <s xml:id="echoid-s5865" xml:space="preserve">garnit de lit de grand faſcinage dont le <lb/>gros bout eſt éloigné d’environ 4 pouces du placage, auquel on <lb/>fait ſuivre le talud que doit avoir le parapet après en avoir recoupé <lb/>le parement, & </s> <s xml:id="echoid-s5866" xml:space="preserve">comme ſa hauteur au-deſſus de la banquette eſt <lb/>toûjours de quatre pieds & </s> <s xml:id="echoid-s5867" xml:space="preserve">demi, ſon talud eſt de 18 pouces qui <lb/>eſt le 6<emph style="sub">e</emph> de la hauteur. </s> <s xml:id="echoid-s5868" xml:space="preserve">Quant au talud exterieur, on lui donne les <lb/>deux tiers de la hauteur; </s> <s xml:id="echoid-s5869" xml:space="preserve">c’eſt-à-dire que quand un ouvrage eſt re-<lb/>vêtu de gaſon ou de placage, s’il a exterieurement 18 pieds de <lb/>hauteur, on lui en donne 12 de talud.</s> <s xml:id="echoid-s5870" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5871" xml:space="preserve">Les revêtemens de gaſonnage ſe font à peu-près comme le pré-<lb/>cedent; </s> <s xml:id="echoid-s5872" xml:space="preserve">car on commence par poſer une premiere aſſiſe de gaſon <lb/>au-deſſous du niveau de la derniere banquette pour ſervir de baſe <lb/>ou de merande aux autres qu’on doit élever deſſus, tous les gaſons <lb/>dont on ſe ſert doivent avoir 15 à 16 pouces de queuë ſur 6 de <lb/>largeur & </s> <s xml:id="echoid-s5873" xml:space="preserve">autant de hauteur taillés en coin de mire, cette hauteur <lb/>de 6 pouces eſt réduite à 4 après que le gaſon eſt mis en œuvre. <lb/></s> <s xml:id="echoid-s5874" xml:space="preserve">Sur cette premiere aſſiſe on en poſe une ſeconde, & </s> <s xml:id="echoid-s5875" xml:space="preserve">ſur celle-ci <lb/>une troiſiéme bien diſpoſée à joints recouverts & </s> <s xml:id="echoid-s5876" xml:space="preserve">conduits de ni-<lb/>veau ſur toute la longueur de l’ouvrage, ces aſſiſes ſont entre-laſſées <lb/>avec des brins de ſaule & </s> <s xml:id="echoid-s5877" xml:space="preserve">quelque-fois de chiendent de même qu’au <lb/>placage, & </s> <s xml:id="echoid-s5878" xml:space="preserve">de 3 aſſiſes, en 3 aſſiſes, on étend un lit de grand faſci-<lb/>nage qu’on recouvre de terre bien battuë pour former le parapet, <lb/>& </s> <s xml:id="echoid-s5879" xml:space="preserve">à meſure que l’ouvrage avance, on recoupe le parement pour <lb/>qu’il ſoit bien uni & </s> <s xml:id="echoid-s5880" xml:space="preserve">faſſe le même effet que s’il étoit de Maçonne-<lb/>rie; </s> <s xml:id="echoid-s5881" xml:space="preserve">tous les angles ſaillans d’un parapet interieur ou exterieur ſe <lb/>font en arrondiſſant, parce qu’autrement il ſeroit bien-tôt émouſſé, <lb/>c’eſt même dans ces endroits où la main du Gaſonneur montre ſon <lb/>adreſſe.</s> <s xml:id="echoid-s5882" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5883" xml:space="preserve">Le gaſon, pour être bon, doit être coupé dans un pré bien herbu <lb/>& </s> <s xml:id="echoid-s5884" xml:space="preserve">racineux un peu humide, les prés qui ſont tourbeux ou ſablo- <pb o="87" file="0275" n="286" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> neux ne valent rien pour cela; </s> <s xml:id="echoid-s5885" xml:space="preserve">toutes les ſaiſons ne ſont pas propres <lb/>non plus pour le gaſonnage, le tems le plus convenable eſt le Prin-<lb/>tems & </s> <s xml:id="echoid-s5886" xml:space="preserve">l’Automne.</s> <s xml:id="echoid-s5887" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5888" xml:space="preserve">Il faut environ 250 gaſons & </s> <s xml:id="echoid-s5889" xml:space="preserve">12 faſcines pour une toiſe quarrée <lb/>de gaſonnage, il ſemble que 216 gaſons devroient ſuffire, mais on <lb/>en compte 40 de plus pour remplacer ceux de rebut, un bon ga-<lb/>ſon peſe ordinairement 15 liv. </s> <s xml:id="echoid-s5890" xml:space="preserve">& </s> <s xml:id="echoid-s5891" xml:space="preserve">un Chariot en voiture 100.</s> <s xml:id="echoid-s5892" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5893" xml:space="preserve">Un bon Coupeur de gaſons peut en couper juſqu’à 1500 dans <lb/>un jour d’Eté & </s> <s xml:id="echoid-s5894" xml:space="preserve">la moitié ſeulement dans un jour d’Hyver, le Ga-<lb/>ſonneur en peut poſer & </s> <s xml:id="echoid-s5895" xml:space="preserve">raſer 10 toiſes quarrées dans un jour, & </s> <s xml:id="echoid-s5896" xml:space="preserve"><lb/>même d’avantage s’il’eſt bien ſervi pour la terre & </s> <s xml:id="echoid-s5897" xml:space="preserve">pour la faſcine.</s> <s xml:id="echoid-s5898" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5899" xml:space="preserve">Je ne dis rien ici du tunage & </s> <s xml:id="echoid-s5900" xml:space="preserve">du clayonage, parce que je me <lb/>propoſe d’en parler dans l’Architecture Ydraulique; </s> <s xml:id="echoid-s5901" xml:space="preserve">je paſſe auſſi <lb/>ſous filence quantité de petits détails au ſujet de la maniere de tra-<lb/>vailler les terres, qui ne ſont point aſſés de conſequence pour me-<lb/>riter une attention particuliere.</s> <s xml:id="echoid-s5902" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5903" xml:space="preserve">A l’égard des Foſſes qui environnent les ouvrages, leur excava-<lb/>tion ne doit point être plus profonde que le niveau de la derniere <lb/>retraite des fondemens; </s> <s xml:id="echoid-s5904" xml:space="preserve">mais quand ils ſont à ſec, on obſerve pour-<lb/>tant de leur donner un peu de talud en venant du pied du rempart <lb/>dans le milieu, & </s> <s xml:id="echoid-s5905" xml:space="preserve">du pied de la contreſcarpe dans le même milieu <lb/>afin de faciliter l’écoulement des eaux de pluye.</s> <s xml:id="echoid-s5906" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5907" xml:space="preserve">Quand la contreſcarpe n’eſt point revêtuë, on donne aux bords <lb/>du Foſſé un talud égal à ſa profondeur, & </s> <s xml:id="echoid-s5908" xml:space="preserve">à meſure qu’on aprofon-<lb/>dit, on fait d’abord des banquettes au lieu de talud pour faciliter <lb/>les allées & </s> <s xml:id="echoid-s5909" xml:space="preserve">venuës des travailleurs: </s> <s xml:id="echoid-s5910" xml:space="preserve">&</s> <s xml:id="echoid-s5911" xml:space="preserve">, après’que la vuidange eſt <lb/>faite, ces banquettes ſont coupées pour former le talud dont je <lb/>viens de parler. </s> <s xml:id="echoid-s5912" xml:space="preserve">On donne auſſi un ſemblable talud au pied des ou-<lb/>vrages de terraſſe qui ont une berme.</s> <s xml:id="echoid-s5913" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5914" xml:space="preserve">Je ne parle point de la largeur ni de la hauteur que l’on donne <lb/>au terre-plain des rempars, parce que cela doit être reglé par les <lb/>profils, je dirai cependant que le talud interieur de tous les rem-<lb/>parts ont une fois & </s> <s xml:id="echoid-s5915" xml:space="preserve">demi leur hauteur; </s> <s xml:id="echoid-s5916" xml:space="preserve">c’eſt-à-dire que ſi un <lb/>rempart à 12 pieds de haut, on lui en donnera 18 de talud.</s> <s xml:id="echoid-s5917" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5918" xml:space="preserve">Je ne dois point oublier de dire ici que quand on forme les faces <lb/> <anchor type="note" xlink:label="note-0275-01a" xlink:href="note-0275-01"/> des Baſtions, demi-Lunes, contre-Gardes, &</s> <s xml:id="echoid-s5919" xml:space="preserve">c. </s> <s xml:id="echoid-s5920" xml:space="preserve">on obſerve de leur <lb/>donner plus d’élevation aux angles ſaillans qu’aux extrêmités: </s> <s xml:id="echoid-s5921" xml:space="preserve">je <lb/>veux dire que ces faces ont une petite pente en venant de l’angle <lb/>ſaillant aux extrêmités, qui eſt reglée ſuivant la longueur que doi-<lb/>vent avoir ces faces, cela contribuë à donner plus de grace à un ou-<lb/>vrage & </s> <s xml:id="echoid-s5922" xml:space="preserve">à le couvrir contre les enfilades. </s> <s xml:id="echoid-s5923" xml:space="preserve">Mais quand on a ſeule- <pb o="88" file="0276" n="287" rhead="LA SCIENCE DES INGENIEURS,"/> ment ce dernier motif en vûe, il y en a qui aiment mieux faire des <lb/>ſur-touts aux angles ſaillans. </s> <s xml:id="echoid-s5924" xml:space="preserve">J’ajoûterai auſſi, qu’on donne aux rem-<lb/>parts & </s> <s xml:id="echoid-s5925" xml:space="preserve">parapets des Ouvrages, un peu plus d’élevation que celle <lb/>qui a été reglée par les profils, pour prévenir les réductions que <lb/>cauſent les affaiſſemens.</s> <s xml:id="echoid-s5926" xml:space="preserve"/> </p> <div xml:id="echoid-div289" type="float" level="3" n="1"> <note position="right" xlink:label="note-0275-01" xlink:href="note-0275-01a" xml:space="preserve">Voyez la <lb/>14<emph style="sub">e</emph>. Plan-<lb/>che qui <lb/>comprend <lb/>l’élevation <lb/>d’un front@ <lb/>de Fortifi-<lb/>cation.</note> </div> <p> <s xml:id="echoid-s5927" xml:space="preserve">Quand on fait des demi revêtemens aux ouvrages, on y laiſſe <lb/>quelque-fois une berme de 10 pieds de largeur pour une haye vive, <lb/>qui ſe fait d’Epines blanches provenans de jeunes plantes pépinieres. <lb/></s> <s xml:id="echoid-s5928" xml:space="preserve">Elle ſe plante ſur deux lignes, dont la premiere eſt à 5 pieds du <lb/>parapet, & </s> <s xml:id="echoid-s5929" xml:space="preserve">la ſeconde à 2 pieds de la premiere, on la laboure de <lb/>tems en tems, & </s> <s xml:id="echoid-s5930" xml:space="preserve">au bout de trois ans on la récépe tout près de terre, <lb/>trois autres années après la haye s’étant élévée à une certaine hau-<lb/>teur on entre-laſſe tous ſes brins les uns dans les autres, de maniere <lb/>qu’ils faſſent un tiſſu de 4 à 5 pieds, ce qui ſe doit répéter tous les <lb/>ans, juſqu’à ce qu’elle ſoit parvenuë à la hauteur de 6 pieds, on la <lb/>taille proprement devant & </s> <s xml:id="echoid-s5931" xml:space="preserve">derriere afin qu’elle s’épaiſſiſſe mieux, <lb/>& </s> <s xml:id="echoid-s5932" xml:space="preserve">on la laiſſe anticiper juſqu’à la moitié de l’épaiſſeur du revête-<lb/>ment au ſommet afin qu’il ne reſte d’autre eſpace que celui quiſera <lb/>neceſſaire pour le paſſage du Jardinier qui la cultivera.</s> <s xml:id="echoid-s5933" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5934" xml:space="preserve">On plante ordinairement des Arbres ſur le Rempart de la Place <lb/>trois ou quatre ans après qu’on l’a élevé, afin que les terres ayent <lb/>eû le tems de s’affaiſſer: </s> <s xml:id="echoid-s5935" xml:space="preserve">on en met trois rangées; </s> <s xml:id="echoid-s5936" xml:space="preserve">la premiere ſe <lb/>fait au pied de la banquette, la ſeconde à trois ou quatre pieds du <lb/>bord interieur du terre-plain, & </s> <s xml:id="echoid-s5937" xml:space="preserve">la troiſiéme au pied du talud du <lb/>rempart. </s> <s xml:id="echoid-s5938" xml:space="preserve">On choiſit des Ormes d’une belle tige, bien garnis de leurs <lb/>racines, qui ne doivent être ni alterées ni offenſées; </s> <s xml:id="echoid-s5939" xml:space="preserve">quant à leur <lb/>groſſeur, il ſuffit qu’ils ayent 6 à 7 pouces de pourtour, parce qu’ils <lb/>en reprennent mieux que s’ils étoient plus forts: </s> <s xml:id="echoid-s5940" xml:space="preserve">on les plante à <lb/>15 pieds de diſtance les uns des autres, faiſant des trous de 3 pieds <lb/>en quarré ſur autant de profondeur. </s> <s xml:id="echoid-s5941" xml:space="preserve">Il eſt à propos de faire ces trous <lb/>trois ou quatre mois avant de planter les Arbres, afin que le fonds <lb/>puiſſe s’engraiſſer. </s> <s xml:id="echoid-s5942" xml:space="preserve">On a encore beaucoup d’autres petites atten-<lb/>tions, qui ſont eſſentielles pour les faire profiter, mais qui ſont aſſés <lb/>connuës des Jardiniers pour me diſpenſer d’en faire le détail.</s> <s xml:id="echoid-s5943" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5944" xml:space="preserve">Je n’ai pas encore parlé du chemin couvert, parce que ſa conſ-<lb/>truction n’a rien qui ne ſoit renfermé dans ce qu’on a vû au ſujet <lb/>de la maniere de conſtruire les Ouvrages de terraſſe; </s> <s xml:id="echoid-s5945" xml:space="preserve">je dirai pour-<lb/>tânt, qu’on lui donne ordinairement 6 toiſes de largeur formé par <lb/>un parapet de 4 pieds & </s> <s xml:id="echoid-s5946" xml:space="preserve">demi de haut élevé ſur deux ou trois ban-<lb/>quetes ſelon qu’on eſt obligé de ſe couvrir contre la campagne: <lb/></s> <s xml:id="echoid-s5947" xml:space="preserve">quelquefois l’on ſoûtient ce parapet d’un petit revêtement de Ma- <pb o="89" file="0277" n="288" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> çonnerie qu’on ne conſtruit qu’après que les terres ſe ſont bien <lb/>affermies, on l’établit ſur une fondation de trois ou quatre tas de <lb/>brique de hauteur, ſur 2 briques & </s> <s xml:id="echoid-s5948" xml:space="preserve">demi d’épaiſſeur, & </s> <s xml:id="echoid-s5949" xml:space="preserve">on lui <lb/>donne deux briques ſur la baſe & </s> <s xml:id="echoid-s5950" xml:space="preserve">une brique & </s> <s xml:id="echoid-s5951" xml:space="preserve">demi au ſommet <lb/>ſur trois pieds de hauteur, le reſte du parapet qui eſt d’un pied & </s> <s xml:id="echoid-s5952" xml:space="preserve"><lb/>demi, ſe revêtit de gaſon ou de placage.</s> <s xml:id="echoid-s5953" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5954" xml:space="preserve">Les angles ſaillans des Places d’Armes en raſe campagne doi-<lb/>vent être élevés d’un pied plus que l’éxtrêmité de leur face pour ſe <lb/>couvrir contre les enfilades; </s> <s xml:id="echoid-s5955" xml:space="preserve">dans le milieu de chaque face on pra-<lb/>tique une ſortie coupée à niveau du terre-plain, on lui donne 9 à <lb/>10 pieds de largeur ſur 15 de longueur pris du ſommet du parapet <lb/>& </s> <s xml:id="echoid-s5956" xml:space="preserve">pour défiler le paſſage, on le détourne en arrondiſſant vers l’an-<lb/>gle rentrant, aux deux côtez de chaque ſortie on plante un poteau <lb/>aiguiſé & </s> <s xml:id="echoid-s5957" xml:space="preserve">contre-fiché ſur un ſeüil pour porter deux manteaux <lb/>de barriere que l’on fait de barreaux à claire voye dont le ſommet <lb/>finit en pointe façonnée comme celle des palliſſades, élevé à la <lb/>même hauteur & </s> <s xml:id="echoid-s5958" xml:space="preserve">ſur le même allignement.</s> <s xml:id="echoid-s5959" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5960" xml:space="preserve">Les Places d’Armes rentrantes & </s> <s xml:id="echoid-s5961" xml:space="preserve">ſaillantes ſe ferment ordinaire-<lb/>ment par des traverſes de terre auſquelles on donne 18 pieds d’é-<lb/>paiſſeur au ſommet, leur parapet eſt élevé à la même hauteur que <lb/>celui du chemin couvert, avec le même nombre de Banquettes. <lb/></s> <s xml:id="echoid-s5962" xml:space="preserve">Quand la contreſcarpe eſt revêtuë de Maçonnerie, les profils des <lb/>traverſes le ſont auſſi, ce qui les rend capables d’un plus grand feu <lb/>à cauſe que l’on n’eſt pas obligé de leur donner auſſi grand talud <lb/>de ce côté-là.</s> <s xml:id="echoid-s5963" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5964" xml:space="preserve">A un demi pied du parapet tant du chemin couvert que des tra-<lb/>verſes, on plante ſur la Banquette un rang de paliſſades de bois de <lb/>chêne, de brin ou de quartier, de 8 pieds & </s> <s xml:id="echoid-s5965" xml:space="preserve">demi de longueur ſur <lb/>18 à 20 pouces de tour meſuré au milieu, elles ſont apointées de <lb/>12 à 13 pouces de longueur, la pointe droite ſur le milieu un peu <lb/>tronquée pour éviter la pourriture, on les eſpace également à 2 <lb/>pouces de diſtance l’une de l’autre meſurée ſur le linteau auquel <lb/>elles ſont attachées avec des chevilles de bois de chêne bien ſec, <lb/>chaſſées de force par le gros bout & </s> <s xml:id="echoid-s5966" xml:space="preserve">fendues par le petit, pour être <lb/>contre-chevillées, le linteau ſe fait auſſi de bois de chêne d’une <lb/>piéce de 4 pouces ſur 5 d’écarriſſage, laquelle eſt refenduë diago-<lb/>nalement à un pouce près des angles opoſés, ce qui donne deux <lb/>cours de linteaux. </s> <s xml:id="echoid-s5967" xml:space="preserve">Mr. </s> <s xml:id="echoid-s5968" xml:space="preserve">le Marêchal de Vauban faiſoit ſurmonter la <lb/>pointe des paliſſades de 9 pouces au-deſſus de la crête du parapet; <lb/></s> <s xml:id="echoid-s5969" xml:space="preserve">mais l’uſage à fait connoître que 6 pouces ſuffiſoient & </s> <s xml:id="echoid-s5970" xml:space="preserve">mettoient <lb/>les palliſſades moins en priſe au Canon: </s> <s xml:id="echoid-s5971" xml:space="preserve">on doit les incliner de 6 <pb o="90" file="0278" n="289" rhead="LA SCIENCE DES INGENIEURS,"/> pouces du côté du parapet pour mieux réſiſter à la pouſſée des <lb/>terres, & </s> <s xml:id="echoid-s5972" xml:space="preserve">que le Soldat ſoit plus commodement placé pour fai-<lb/>re feu.</s> <s xml:id="echoid-s5973" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5974" xml:space="preserve">Il entre ordinairement 8 ou 9 palliſſades dans la toiſe courante <lb/>dont chacune péſe environ 70 liv. </s> <s xml:id="echoid-s5975" xml:space="preserve">Un Chariot en voiture 100. </s> <s xml:id="echoid-s5976" xml:space="preserve">& </s> <s xml:id="echoid-s5977" xml:space="preserve">un <lb/>Ouvrier avec ſon manœuvre peut en planter & </s> <s xml:id="echoid-s5978" xml:space="preserve">cheviller trois toi-<lb/>ſes courantes par jour.</s> <s xml:id="echoid-s5979" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5980" xml:space="preserve">Quand un rempart n’eſt revêtu que de gaſons, on le fraiſe à la <lb/>hauteur du terre-plain; </s> <s xml:id="echoid-s5981" xml:space="preserve">c’eſt-à-dire qu’on l’herriſſe de palliſſades <lb/>poſées horiſontalement ayant trois pieds de ſaillie ſur trois pouces <lb/>de pente, elles ſont couchées & </s> <s xml:id="echoid-s5982" xml:space="preserve">chevillées ſur un chevet ou lin-<lb/>teau. </s> <s xml:id="echoid-s5983" xml:space="preserve">Il y a des perſonnes qui ajoûtent un ſecond linteau ſur l’ex-<lb/>trémité qui eſt enterrée, afin qu’on trouve plus de difficulté à les <lb/>arracher; </s> <s xml:id="echoid-s5984" xml:space="preserve">mais cela paroit aſſés inutile. </s> <s xml:id="echoid-s5985" xml:space="preserve">Ces palliſſades ſont eſpa-<lb/>cées les unes des autres de 4 à 5 pouces, il en faut environ 6 à 7 <lb/>par toiſe courante.</s> <s xml:id="echoid-s5986" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5987" xml:space="preserve">Comme les Ouvrages revêtus de gaſons ont ordinairement une <lb/>berme, on y plante auſſi au bord du Foſſé un autre rang de palliſ-<lb/>ſade qui preſente la pointe du côté de la Campagne, on leur fait <lb/>faire un angle de 45 degrés avec l’horiſon, & </s> <s xml:id="echoid-s5988" xml:space="preserve">leur ſaillie eſt à peu <lb/>près de 4 pieds 10 pouces.</s> <s xml:id="echoid-s5989" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s5990" xml:space="preserve">Je crois ne pouvoir mieux finir ce troiſiéme Livre, qu’en rapor-<lb/>tant quelques Réglemens de Mr. </s> <s xml:id="echoid-s5991" xml:space="preserve">le Marêchal de Vauban au ſujet <lb/>des Travaux, qui conviendront parfaitement ici pour donner aux <lb/>jeunes Ingenieurs une idée generale de la façon dont ſe doivent <lb/>faire les toiſés des Ouvrages, & </s> <s xml:id="echoid-s5992" xml:space="preserve">ce qu’il faut ſuivre pour avoir de <lb/>l’ordre & </s> <s xml:id="echoid-s5993" xml:space="preserve">de l’arrangement quand on eſt chargé du détail.</s> <s xml:id="echoid-s5994" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div291" type="section" level="2" n="90"> <head xml:id="echoid-head229" style="it" xml:space="preserve">Réglemens de Mr. le Marêchal de Vauban, pour la Con-<lb/>duite des Travaux.</head> <p> <s xml:id="echoid-s5995" xml:space="preserve">L’Ingenieur qui ſera chargé en Chef des Travaux d’une Place <lb/>fera tous les ans un Regiſtre où chaque Article de l’état des Ou-<lb/>vrages ordonnés pour la même année, aura ſa feüille en particu-<lb/>lier, dans laquelle tous les payemens de la dépenſe ſeront rapor-<lb/>tés en gros & </s> <s xml:id="echoid-s5996" xml:space="preserve">en détail depuis le commencement de ſon execu-<lb/>tion juſqu’à ſa fin, conformément aux marchés qui en auront été <lb/>faits & </s> <s xml:id="echoid-s5997" xml:space="preserve">aux comptes & </s> <s xml:id="echoid-s5998" xml:space="preserve">toiſés qui ſeront arrêtés de tems en tems <lb/>avec les Entrepreneurs; </s> <s xml:id="echoid-s5999" xml:space="preserve">moyennant quoi il lui ſera aiſé, en quel-<lb/>que tems que ce ſoit, de faire voir l’état des Ouvrages dont on <lb/>pourra tirer des connoiſſances neceſſaires pour le tems de leur <pb o="91" file="0279" n="290" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> durée, & </s> <s xml:id="echoid-s6000" xml:space="preserve">les moyens de les pouvoir achever.</s> </p> <p> <s xml:id="echoid-s6001" xml:space="preserve">Les Entrepreneurs n’en commenceront aucun en gros ni en <lb/>détail, qu’on ne leur ait donné la figure & </s> <s xml:id="echoid-s6002" xml:space="preserve">l’étenduë au juſte, <lb/>marqué toutes les hauteurs & </s> <s xml:id="echoid-s6003" xml:space="preserve">profondeurs, & </s> <s xml:id="echoid-s6004" xml:space="preserve">fait un toiſé géné-<lb/>ral, du contenu duquel on leur donnera copie, qu’ils ſigneront. <lb/></s> <s xml:id="echoid-s6005" xml:space="preserve">Après qu’ils les auront achevés, ils ſeront meſurés pour la ſeconde <lb/>fois; </s> <s xml:id="echoid-s6006" xml:space="preserve">& </s> <s xml:id="echoid-s6007" xml:space="preserve">ſi la quantité, qu’on aura trouvée à la fin, differe du com-<lb/>mencement, on prendra toûjours le moindre nombre pour le <lb/>compte du Roy; </s> <s xml:id="echoid-s6008" xml:space="preserve">ce qui ſe doit entendre pour le remuëment des <lb/>terres ſeulement; </s> <s xml:id="echoid-s6009" xml:space="preserve">car pour la maçonnerie il pourroit y avoir des <lb/>changemens dans la fondation, qui ſeroient ſi éloignés du toiſé <lb/>eſtimatif, qu’on ne pourroit pas s’y tenir ſans tomber volontai-<lb/>rement dans une erreur conſiderable.</s> </p> <p> <s xml:id="echoid-s6010" xml:space="preserve">Tous les ouvrages de terre ſeront meſurés par l’excavation <lb/>des foſſés d’où on les aura tirés, à moins qu’il ne fût expreſſe-<lb/>ment ſpecifié par le marché de la faire autrement.</s> </p> <p> <s xml:id="echoid-s6011" xml:space="preserve">Tous les temoins de terre ſeront faits en profils, & </s> <s xml:id="echoid-s6012" xml:space="preserve">non en pi-<lb/>ramide, à cauſe des abus & </s> <s xml:id="echoid-s6013" xml:space="preserve">tromperies qui s’y commettent: </s> <s xml:id="echoid-s6014" xml:space="preserve">& </s> <s xml:id="echoid-s6015" xml:space="preserve"><lb/>ici ſe feront toûjours de concert avec l’Ingenieur, & </s> <s xml:id="echoid-s6016" xml:space="preserve">l’Entrepre-<lb/>neur.</s> </p> <p> <s xml:id="echoid-s6017" xml:space="preserve">L’Ingenieur ne fera payer perſonne à bon compte, ſur les ou-<lb/>vrages, qu’il ne ſoit certain, par un bon meſurage, de la poſſibi-<lb/>lité de le faire ou non, ſans rien hazarder pour le Roy.</s> </p> <p> <s xml:id="echoid-s6018" xml:space="preserve">A l’égard des ouvrages de maçonnerie, on tiendra des atta-<lb/>chemens ou des memoires exacts, ſignés reciproquement de l’In-<lb/>genieur & </s> <s xml:id="echoid-s6019" xml:space="preserve">de l’Entrepreneur, & </s> <s xml:id="echoid-s6020" xml:space="preserve">même des principaux conduc-<lb/>teurs des ouvrages, où toutes les épaiſſeurs, longueurs, & </s> <s xml:id="echoid-s6021" xml:space="preserve">hau-<lb/>teurs de chaque partie, ſeront nettement expliquées, ſpecifiant <lb/>bien l’endroit de chacune, afin d’éviter toute ſorte d’embroüille-<lb/>ment & </s> <s xml:id="echoid-s6022" xml:space="preserve">de ſupercherie dans les toiſés generaux.</s> </p> <p> <s xml:id="echoid-s6023" xml:space="preserve">Pour la charpenterie, on tiendra des attachemens de même <lb/>de tous les bois qui ſeront attachés, & </s> <s xml:id="echoid-s6024" xml:space="preserve">de ceux qui ne le ſeront <lb/>pas, ſpecifiant bien le nom de chaque eſpece, & </s> <s xml:id="echoid-s6025" xml:space="preserve">même figurant <lb/>à la marge, le mieux qu’il ſera poſſible, la partie dont il eſt queſ-<lb/>tion, afin d’éviter toute obſcurité.</s> </p> <p> <s xml:id="echoid-s6026" xml:space="preserve">La même choſe ſera auſſi obſervée pour la maçonnerie, tout <lb/>autant de fois qu’on croira en avoir beſoin, pour plus grand éclair-<lb/>ciſſement.</s> </p> <p> <s xml:id="echoid-s6027" xml:space="preserve">Tous les ouvrages de fer ſeront peſés à la livre de ſeize onces <lb/>en preſence de l’Ingenieur, après qu’ils auront été forgés, avant <lb/>que d’être employés.</s> </p> <pb o="92" file="0280" n="291" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s6028" xml:space="preserve">Ceux de maçonnerie à la toiſe cube, ſi c’eſt de gros murs <lb/>ou à la toiſe quarrée, ſi c’eſt de ſimple mur comme des Cazer-<lb/>nes, magaſins, corps de gardes, & </s> <s xml:id="echoid-s6029" xml:space="preserve">autres.</s> </p> <p> <s xml:id="echoid-s6030" xml:space="preserve">Le meſurage de terre ſe fera à la toiſe cube de France, celui <lb/>des gaſons à queuë, gaſons plats, & </s> <s xml:id="echoid-s6031" xml:space="preserve">placages, à la toiſe quarrée, <lb/>celui de la charpenterie au cent de ſolives.</s> </p> <p> <s xml:id="echoid-s6032" xml:space="preserve">Sur la fin de chaque année, au tems que les ouvrages finiſ-<lb/>ſent, l’Ingenieur arrêtera toutes les dépenſes qui auront été faî-<lb/>tes, ſur ſon regiſtre, & </s> <s xml:id="echoid-s6033" xml:space="preserve">raportera ſur ſon projet de l’année cou-<lb/>rante, l’état où ſeront les ouvrages de la place, & </s> <s xml:id="echoid-s6034" xml:space="preserve">ce que cha-<lb/>cun aura couté, en marge, vis-à-vis de ſon article; </s> <s xml:id="echoid-s6035" xml:space="preserve">contant <lb/>après les revenans bon, ou les dettes qui s’y trouveront, pour fai-<lb/>re état des premiers, comme fonds déja reçus, & </s> <s xml:id="echoid-s6036" xml:space="preserve">des ſeconds, <lb/>comme premier fonds à demander ſur le projet de l’an prochain, <lb/>enſuite dequoi il y travaillera, y raportant tous les ouvrages qui<unsure/> <lb/>auront été reglés, avec l’eſtimation de chacun en particulier, le <lb/>plus juſte qu’il ſera poſſible, afin que l’on puiſſe choiſir ceux que <lb/>l’on jugera les plus neceſſaires: </s> <s xml:id="echoid-s6037" xml:space="preserve">il faudra auſſi raporter aprés cela, <lb/>le prix des materiaux en proviſion, qui tiendront lieu de fonds, <lb/>& </s> <s xml:id="echoid-s6038" xml:space="preserve">à la fin, le nom de tous les gens employés à la fortification, <lb/>& </s> <s xml:id="echoid-s6039" xml:space="preserve">les apointemens d’un chacun; </s> <s xml:id="echoid-s6040" xml:space="preserve">& </s> <s xml:id="echoid-s6041" xml:space="preserve">pourvû que cet ordre ſoit <lb/>exactement obſervé, l’on ne tombera dans aucune erreur, & </s> <s xml:id="echoid-s6042" xml:space="preserve">l’on <lb/>verra toûjours clair dans toutes les dépenſes faites & </s> <s xml:id="echoid-s6043" xml:space="preserve">à faire.</s> </p> <p> <s xml:id="echoid-s6044" xml:space="preserve">Quand on fera des toiſés, ſoit generaux, ſoit particuliers, il <lb/>faudra bien ſpecifier le lieu & </s> <s xml:id="echoid-s6045" xml:space="preserve">l’endroit, la qualité des ou-<lb/>vrages, le nom de la piece & </s> <s xml:id="echoid-s6046" xml:space="preserve">de l’Entrepreneur, & </s> <s xml:id="echoid-s6047" xml:space="preserve">même les <lb/>marquer ſur le plan, par un renvoi chifré, afin que l’on n’aye <lb/>point de peine à le trouver, quand il s’agira de quelque verifi-<lb/>cation.</s> </p> <p> <s xml:id="echoid-s6048" xml:space="preserve">Secondement, d’en donner les longueurs, largeurs, & </s> <s xml:id="echoid-s6049" xml:space="preserve">profon-<lb/>deurs, par toiſes, pieds, & </s> <s xml:id="echoid-s6050" xml:space="preserve">pouces, dans l’ordre marqué ci-après <lb/>avec le produit.</s> </p> <p> <s xml:id="echoid-s6051" xml:space="preserve">Troiſiémement, d’en diſtinguer les portions, quand il s’en trou-<lb/>vera pluſieurs dans la même piece, par premier, ſecond, & </s> <s xml:id="echoid-s6052" xml:space="preserve">troi-<lb/>ſiéme. </s> <s xml:id="echoid-s6053" xml:space="preserve">&</s> <s xml:id="echoid-s6054" xml:space="preserve">c.</s> </p> <p> <s xml:id="echoid-s6055" xml:space="preserve">Quatriémement, d’en faire toûjours la ſuputation par toiſes, <lb/>pieds, & </s> <s xml:id="echoid-s6056" xml:space="preserve">pouces, parce que cette façon s’explique plus claire-<lb/>rement, & </s> <s xml:id="echoid-s6057" xml:space="preserve">eſt plus en uſage, & </s> <s xml:id="echoid-s6058" xml:space="preserve">moins ſujette aux embroüille-<lb/>mens des fractions, que les autres.</s> </p> <p> <s xml:id="echoid-s6059" xml:space="preserve">S’il étoit queſtion, par exemple, de meſurer la vuidange du <lb/>foſſé, vis-à-vis la face d’un Baſtion, & </s> <s xml:id="echoid-s6060" xml:space="preserve">que ce meſurage fut di- <pb o="93" file="0281" n="292" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> viſé en pluſieurs parties: </s> <s xml:id="echoid-s6061" xml:space="preserve">voici comme l’on en dreſſera le toiſé.</s> </p> <p> <s xml:id="echoid-s6062" xml:space="preserve">Toiſé du Tranſport des Terres qui a été fait devant la face droite du <lb/>Baſtion N. </s> <s xml:id="echoid-s6063" xml:space="preserve">pour l’aprofondiſſement de ſon Foſſé & </s> <s xml:id="echoid-s6064" xml:space="preserve">l’élevation de ſon <lb/>Rempart, entrepris par.</s> <s xml:id="echoid-s6065" xml:space="preserve">..</s> <s xml:id="echoid-s6066" xml:space="preserve">. & </s> <s xml:id="echoid-s6067" xml:space="preserve">ſes Aſſociés, à raiſon de 50 ſ. </s> <s xml:id="echoid-s6068" xml:space="preserve">pour <lb/>la toiſe cube, marché fait le .</s> <s xml:id="echoid-s6069" xml:space="preserve">.. </s> <s xml:id="echoid-s6070" xml:space="preserve">du mois de .</s> <s xml:id="echoid-s6071" xml:space="preserve">.. </s> <s xml:id="echoid-s6072" xml:space="preserve">de l’année .</s> <s xml:id="echoid-s6073" xml:space="preserve">.. <lb/></s> <s xml:id="echoid-s6074" xml:space="preserve">achevé le .</s> <s xml:id="echoid-s6075" xml:space="preserve">.. </s> <s xml:id="echoid-s6076" xml:space="preserve">du mois de .</s> <s xml:id="echoid-s6077" xml:space="preserve">.. </s> <s xml:id="echoid-s6078" xml:space="preserve">de la même année.</s> <s xml:id="echoid-s6079" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div292" type="section" level="2" n="91"> <head xml:id="echoid-head230" xml:space="preserve">PREMIERE PARTIE.</head> <head xml:id="echoid-head231" style="it" xml:space="preserve">A commencer de la pointe du Baſtion en tirant vers l’épaule.</head> <note position="right" xml:space="preserve"># # toiſes. # pieds. # pouces. # } <lb/>Longueur. # 32 # 3 # 6 # toiſes. # pieds. # pouces. <lb/>Largeur réduite. # 12 # 4 # 8 # 1249 # 0 # 0 <lb/>Profondeur. # 3 # 0 # 0 <lb/></note> </div> <div xml:id="echoid-div293" type="section" level="2" n="92"> <head xml:id="echoid-head232" xml:space="preserve">SECONDE PARTIE.</head> <note position="right" xml:space="preserve"># # toiſes. # pieds # pouces. # } <lb/>Longueur. # 8 # 3 # 0 # # toiſes. # pieds. # pouces. <lb/>Largeur. # 12 # 4 # 8 # 325 # 5 # 0 <lb/>Profondeur. # 3 # 0 # 0 <lb/></note> </div> <div xml:id="echoid-div294" type="section" level="2" n="93"> <head xml:id="echoid-head233" xml:space="preserve">TROISIE’ ME PARTIE.</head> <head xml:id="echoid-head234" style="it" xml:space="preserve">Joignant l’épaule du même côté attenant à la précédente.</head> <note position="right" xml:space="preserve"># # toiſes. # pieds. # pouces. # } <lb/>Longueur. # 12 # 0 # 0 # toiſes. # pieds. # pouces. <lb/>Largeur. # 12 # 4 # 8 # 460 # 0 # 0 <lb/>Profondeur. # 3 # 0 # 0 <lb/><emph style="sc">Total</emph>. # # # # toiſes. # pieds. # pouces. <lb/># # # # # 2034 # 5 # 0 <lb/></note> <p style="it"> <s xml:id="echoid-s6080" xml:space="preserve">Qui à raiſon de 50 ſ. </s> <s xml:id="echoid-s6081" xml:space="preserve">la Toiſe cube, font la <lb/>ſomme de 5087 liv. </s> <s xml:id="echoid-s6082" xml:space="preserve">1 ſ. </s> <s xml:id="echoid-s6083" xml:space="preserve">8 d.</s> <s xml:id="echoid-s6084" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6085" xml:space="preserve">Quand il s’agit de meſurer de la Maçonnerie, ſi c’eſt à la toiſe <lb/>cube, on tiendra le même ordre, expliquant toûjours les trois <lb/>dimenſions; </s> <s xml:id="echoid-s6086" xml:space="preserve">& </s> <s xml:id="echoid-s6087" xml:space="preserve">ſi c’éoit à la toiſe quarrée, on n’en expliquera que <lb/>deux longeur & </s> <s xml:id="echoid-s6088" xml:space="preserve">largeur, ce qui ſe fait particulierement pour le <lb/>gaſonage, placage, &</s> <s xml:id="echoid-s6089" xml:space="preserve">c.</s> </p> <pb o="94" file="0282" n="293" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s6090" xml:space="preserve">Du ſurplus il faudra que les toiſés ſoient purs & </s> <s xml:id="echoid-s6091" xml:space="preserve">nets; </s> <s xml:id="echoid-s6092" xml:space="preserve">c’eſt-à-<lb/>dire, qu’on ne les doit augmenter pour y comprendre la dépenſe <lb/>d’autres ouvrages qui n’auroient pas été réſolus quelque petits <lb/>qu’ils ſoient, il ne faut non plus faire aucune diverſion des fonds <lb/>qui auront été ordonnés pour la dépenſe des Ouvrages pour les <lb/>employer à un autre, tels que pourroient être les défections, ré-<lb/>parations des Bâtimens, comme Corps de Gardes, Arſenaux, <lb/>Magaſins, &</s> <s xml:id="echoid-s6093" xml:space="preserve">c.</s> </p> <p> <s xml:id="echoid-s6094" xml:space="preserve">Quand ils ont beſoin de réparations, illes faut comprendre dans <lb/>le projet & </s> <s xml:id="echoid-s6095" xml:space="preserve">en répreſenter la neceſſité au Miniſtre, attendu que <lb/>tout toiſé augmenté eſt fort ſuſpect & </s> <s xml:id="echoid-s6096" xml:space="preserve">de mauvais exemple, bien <lb/>que la fin pour laquelle on l’auroit fait fût la plus juſte du mon-<lb/>de; </s> <s xml:id="echoid-s6097" xml:space="preserve">car il eſt à ſupoſer que les Ouvrages dont la dépenſe a été <lb/>ordonnée par le Miniſtre, ſont toûjours les plus preſſés, & </s> <s xml:id="echoid-s6098" xml:space="preserve">ſur <lb/>cela on ne la doit point employer à d’autres. </s> <s xml:id="echoid-s6099" xml:space="preserve">Tenir pour maxime <lb/>indubitable, que toutes celles des Fortifications, qui contribuent <lb/>le plus à mettre une Place en ſûreté, ſont toûjours préferables aux <lb/>autres, de quelque nature qu’ils puiſſent être.</s> </p> <p> <s xml:id="echoid-s6100" xml:space="preserve">Que ſi pendant le cours d’une année il vient à tomber quelque <lb/>choſe dans un ouvrage qu’on n’ait pas prévû, comme cela arrive <lb/>fort ſouvent, il faut en faire une eſtimation particuliere, & </s> <s xml:id="echoid-s6101" xml:space="preserve">en <lb/>donner promptement avis au Miniſtre à qui on en fera connoître <lb/>la conſequence, afin qu’il ordonne de nouveaux fonds pour cela.</s> </p> <p> <s xml:id="echoid-s6102" xml:space="preserve">A l’égard des eſtimations, ſupoſé qu’il s’agiſſe de faire celle <lb/>d’une demi-Lune que l’on veut gaſonner, fraiſer, & </s> <s xml:id="echoid-s6103" xml:space="preserve">palliſſader ſur <lb/>la Berme ou dans le Foſſé, voici comme on procedera, après avoir <lb/>expliqué le lieu & </s> <s xml:id="echoid-s6104" xml:space="preserve">la ſituation.</s> </p> </div> <div xml:id="echoid-div295" type="section" level="2" n="94"> <head xml:id="echoid-head235" style="it" xml:space="preserve">Eſtimation d’une demi-Lune ſituée entre les Baſtious N & O, & c.<anchor type="note" xlink:label="note-0282-01a" xlink:href="note-0282-01"/> </head> <p> <s xml:id="echoid-s6105" xml:space="preserve">Eſtimé à raiſon de 45 ſ. </s> <s xml:id="echoid-s6106" xml:space="preserve">la toiſe cube, font la ſomme de 7200l.</s> <s xml:id="echoid-s6107" xml:space="preserve"/> </p> <div xml:id="echoid-div295" type="float" level="3" n="1"> <note position="right" xlink:label="note-0282-01" xlink:href="note-0282-01a" xml:space="preserve"># toiſes. # pieds. # pouces. # } <lb/>Circuit du Foſſé. # 10 # 4 # 0 # toiſes. # pieds. # pouces. <lb/>Largeur réduite du Foſſé. # 120 # 0 # 0 # 2300 # 0 # 0 <lb/>Profondeur. # 2 # 3 # 0 <lb/></note> </div> </div> <div xml:id="echoid-div297" type="section" level="2" n="95"> <head xml:id="echoid-head236" style="it" xml:space="preserve">Gaſonnage à queuë pour l’exterieur de la demi-Lune.</head> <note position="right" xml:space="preserve"># toiſes. # pieds. # pouces. # } <lb/>Longueur. # 118 # 0 # 0 # toiſes. <lb/>Hauteur. # 3 # 0 # 0 # 354 <lb/></note> <pb o="95" file="0283" n="294" rhead="LIVRE III. DE LA CONSTRUCTION DES TRAVAUX."/> </div> <div xml:id="echoid-div298" type="section" level="2" n="96"> <head xml:id="echoid-head237" style="it" xml:space="preserve">Gaſonnage interieur du Parapet & Banquette.</head> <note position="right" xml:space="preserve"># toiſes. # pieds. <lb/>Longueur. # 100 # 0 # } # toiſes. # pieds. <lb/>Hauteur réduite. # 1 # 1 # 116 # 4 <lb/></note> <p style="it"> <s xml:id="echoid-s6108" xml:space="preserve"><emph style="sc">Total</emph> du Gaſonnage à queuë.</s> <s xml:id="echoid-s6109" xml:space="preserve">..</s> <s xml:id="echoid-s6110" xml:space="preserve">.. </s> <s xml:id="echoid-s6111" xml:space="preserve">469 toiſes 4 pieds, ou ſi <lb/>l’on veut 470 toiſes, quarrées, qui eſtimées à raiſon de 40 ſ. </s> <s xml:id="echoid-s6112" xml:space="preserve">chaque toiſe <lb/>font. </s> <s xml:id="echoid-s6113" xml:space="preserve">. </s> <s xml:id="echoid-s6114" xml:space="preserve">. </s> <s xml:id="echoid-s6115" xml:space="preserve">. </s> <s xml:id="echoid-s6116" xml:space="preserve">. </s> <s xml:id="echoid-s6117" xml:space="preserve">. </s> <s xml:id="echoid-s6118" xml:space="preserve">. </s> <s xml:id="echoid-s6119" xml:space="preserve">. </s> <s xml:id="echoid-s6120" xml:space="preserve">940 l.</s> <s xml:id="echoid-s6121" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div299" type="section" level="2" n="97"> <head xml:id="echoid-head238" style="it" xml:space="preserve">Gaſons plats ſur le Parapet & ſur les Banquettes.</head> <note position="right" xml:space="preserve"># toiſes. # pieds. <lb/>Longueur. # 100 # 0 # } # toiſes. # pieds. # pouces. <lb/>Largeur réduite. # 4 # 2 # # 433 # 2 # 0 <lb/></note> <p style="it"> <s xml:id="echoid-s6122" xml:space="preserve">Qui eſtimées à raiſon de 8 ſ. </s> <s xml:id="echoid-s6123" xml:space="preserve">la toiſe quarrée font la ſomme de 173 l. </s> <s xml:id="echoid-s6124" xml:space="preserve">6 ſ. </s> <s xml:id="echoid-s6125" xml:space="preserve">8 d.</s> <s xml:id="echoid-s6126" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s6127" xml:space="preserve">Pour 958 toiſes quarrées de faſcinage de 10 pieds de long, à raiſon de <lb/>10 ſ. </s> <s xml:id="echoid-s6128" xml:space="preserve">pour chaque toiſe quarrée. </s> <s xml:id="echoid-s6129" xml:space="preserve">. </s> <s xml:id="echoid-s6130" xml:space="preserve">. </s> <s xml:id="echoid-s6131" xml:space="preserve">. </s> <s xml:id="echoid-s6132" xml:space="preserve">. </s> <s xml:id="echoid-s6133" xml:space="preserve">479 l.</s> <s xml:id="echoid-s6134" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s6135" xml:space="preserve">Circuit réduit de la fraiſe & </s> <s xml:id="echoid-s6136" xml:space="preserve">de la palliſſade, à raiſon de 6 l. </s> <s xml:id="echoid-s6137" xml:space="preserve">par toiſe <lb/>courante à tout fournir. </s> <s xml:id="echoid-s6138" xml:space="preserve">. </s> <s xml:id="echoid-s6139" xml:space="preserve">. </s> <s xml:id="echoid-s6140" xml:space="preserve">. </s> <s xml:id="echoid-s6141" xml:space="preserve">1230 l.</s> <s xml:id="echoid-s6142" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s6143" xml:space="preserve"><emph style="sc">Total</emph> du contenu de cette Eſtimation. </s> <s xml:id="echoid-s6144" xml:space="preserve">. </s> <s xml:id="echoid-s6145" xml:space="preserve">10112 l. </s> <s xml:id="echoid-s6146" xml:space="preserve">6 ſ. </s> <s xml:id="echoid-s6147" xml:space="preserve">8 d.</s> <s xml:id="echoid-s6148" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6149" xml:space="preserve">Qand il y aura quelqu’autres parties, il faudra auſſi les ſpe-<lb/>cifier, comme les Ponts de communication, épuiſement d’eau, <lb/>le revêtement des Profils, Corps de Gardes, & </s> <s xml:id="echoid-s6150" xml:space="preserve">Réduits: </s> <s xml:id="echoid-s6151" xml:space="preserve">cette <lb/>maniere doit être pratiquée dans les Eſtimations génerales, deſ-<lb/>quelles il faudra tirer des Abregés dont un article comprendra la <lb/>dépenſe d’une piéce entiere en cette maniere.</s> </p> <p> <s xml:id="echoid-s6152" xml:space="preserve">Pour la façon de la demi-Lune or donnée entre les Baſtions N & </s> <s xml:id="echoid-s6153" xml:space="preserve">O, toute <lb/>dépenſe payée, la ſomme de. </s> <s xml:id="echoid-s6154" xml:space="preserve">. </s> <s xml:id="echoid-s6155" xml:space="preserve">. </s> <s xml:id="echoid-s6156" xml:space="preserve">. </s> <s xml:id="echoid-s6157" xml:space="preserve">10112 1. </s> <s xml:id="echoid-s6158" xml:space="preserve">6 ſ. </s> <s xml:id="echoid-s6159" xml:space="preserve">8 d.</s> <s xml:id="echoid-s6160" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6161" xml:space="preserve">Il ne ſera pas neceſſaire d’en faire d’autre détail, puiſqu’il aura <lb/>été fait dans l’Eſtimation generale à laquelle il faudra avoir recours <lb/>pour plus grand éclairciſſement, & </s> <s xml:id="echoid-s6162" xml:space="preserve">c’eſt de cet Extrait ou Abregé <lb/>qu’il faudra tous les ans tirer les projets de depenſes. </s> <s xml:id="echoid-s6163" xml:space="preserve">Voilà à peu <lb/>près quel en ſera le formulaire.</s> </p> </div> <div xml:id="echoid-div300" type="section" level="2" n="98"> <head xml:id="echoid-head239" style="it" xml:space="preserve">Abregé de Dépenſe reſtante à faire pour mettre les Fortifications de la <lb/>Ville en leur entiere perfection.</head> <p style="it"> <s xml:id="echoid-s6164" xml:space="preserve">Pour la façon d’une demi-Lune de terre ordonnée entre les Baſtions de <lb/>France & </s> <s xml:id="echoid-s6165" xml:space="preserve">de Bourgogne, toute dépenſe payée, la ſomme de . </s> <s xml:id="echoid-s6166" xml:space="preserve">. </s> <s xml:id="echoid-s6167" xml:space="preserve">. </s> <s xml:id="echoid-s6168" xml:space="preserve">12000 l,</s> </p> <pb o="96" file="0284" n="295" rhead="LA SCIENCE DES INGENIEURS,"/> <p style="it"> <s xml:id="echoid-s6169" xml:space="preserve">Pour celle du Reduit du Corps de Garde de ladite demi-Lune la <lb/>ſomme de . </s> <s xml:id="echoid-s6170" xml:space="preserve">. </s> <s xml:id="echoid-s6171" xml:space="preserve">. </s> <s xml:id="echoid-s6172" xml:space="preserve">. </s> <s xml:id="echoid-s6173" xml:space="preserve">. </s> <s xml:id="echoid-s6174" xml:space="preserve">. </s> <s xml:id="echoid-s6175" xml:space="preserve">. </s> <s xml:id="echoid-s6176" xml:space="preserve">2500 l.</s> <s xml:id="echoid-s6177" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s6178" xml:space="preserve">Pour achever le nettoyement des Foſſez de la Place. </s> <s xml:id="echoid-s6179" xml:space="preserve">. </s> <s xml:id="echoid-s6180" xml:space="preserve">6000</s> </p> <p style="it"> <s xml:id="echoid-s6181" xml:space="preserve">Pour la façon d’une Ecluſe au bas du Chemin couvert la <lb/>ſomme de. </s> <s xml:id="echoid-s6182" xml:space="preserve">. </s> <s xml:id="echoid-s6183" xml:space="preserve">. </s> <s xml:id="echoid-s6184" xml:space="preserve">. </s> <s xml:id="echoid-s6185" xml:space="preserve">. </s> <s xml:id="echoid-s6186" xml:space="preserve">. </s> <s xml:id="echoid-s6187" xml:space="preserve">. </s> <s xml:id="echoid-s6188" xml:space="preserve">. </s> <s xml:id="echoid-s6189" xml:space="preserve">8400</s> </p> <p style="it"> <s xml:id="echoid-s6190" xml:space="preserve">Pour ſix milliers de Palliſſades. </s> <s xml:id="echoid-s6191" xml:space="preserve">. </s> <s xml:id="echoid-s6192" xml:space="preserve">. </s> <s xml:id="echoid-s6193" xml:space="preserve">. </s> <s xml:id="echoid-s6194" xml:space="preserve">3000</s> </p> <p style="it"> <s xml:id="echoid-s6195" xml:space="preserve">Applaniſſemens des Monticules, Cavins, & </s> <s xml:id="echoid-s6196" xml:space="preserve">Comblemens de <lb/>Foſſez. </s> <s xml:id="echoid-s6197" xml:space="preserve">. </s> <s xml:id="echoid-s6198" xml:space="preserve">. </s> <s xml:id="echoid-s6199" xml:space="preserve">. </s> <s xml:id="echoid-s6200" xml:space="preserve">. </s> <s xml:id="echoid-s6201" xml:space="preserve">. </s> <s xml:id="echoid-s6202" xml:space="preserve">. </s> <s xml:id="echoid-s6203" xml:space="preserve">. </s> <s xml:id="echoid-s6204" xml:space="preserve">4500</s> </p> <p style="it"> <s xml:id="echoid-s6205" xml:space="preserve">Réparations des Chemins couverts. </s> <s xml:id="echoid-s6206" xml:space="preserve">. </s> <s xml:id="echoid-s6207" xml:space="preserve">. </s> <s xml:id="echoid-s6208" xml:space="preserve">. </s> <s xml:id="echoid-s6209" xml:space="preserve">4200</s> </p> <p style="it"> <s xml:id="echoid-s6210" xml:space="preserve">La façon & </s> <s xml:id="echoid-s6211" xml:space="preserve">fourniture de ſix Plate-formes ſur les Batteries <lb/>à barbettes du Baſtion G. </s> <s xml:id="echoid-s6212" xml:space="preserve">. </s> <s xml:id="echoid-s6213" xml:space="preserve">. </s> <s xml:id="echoid-s6214" xml:space="preserve">. </s> <s xml:id="echoid-s6215" xml:space="preserve">. </s> <s xml:id="echoid-s6216" xml:space="preserve">1200</s> </p> <p style="it"> <s xml:id="echoid-s6217" xml:space="preserve">Il eſt dû à l’Entrepreneur ſur les Ouvrages de l’année <lb/>paſſée la ſomme de. </s> <s xml:id="echoid-s6218" xml:space="preserve">. </s> <s xml:id="echoid-s6219" xml:space="preserve">. </s> <s xml:id="echoid-s6220" xml:space="preserve">. </s> <s xml:id="echoid-s6221" xml:space="preserve">. </s> <s xml:id="echoid-s6222" xml:space="preserve">. </s> <s xml:id="echoid-s6223" xml:space="preserve">. </s> <s xml:id="echoid-s6224" xml:space="preserve">1500</s> </p> <p style="it"> <s xml:id="echoid-s6225" xml:space="preserve">Frais inprévus, journées, & </s> <s xml:id="echoid-s6226" xml:space="preserve">accidens ſurvenus dans le cours <lb/>du travail. </s> <s xml:id="echoid-s6227" xml:space="preserve">. </s> <s xml:id="echoid-s6228" xml:space="preserve">. </s> <s xml:id="echoid-s6229" xml:space="preserve">. </s> <s xml:id="echoid-s6230" xml:space="preserve">. </s> <s xml:id="echoid-s6231" xml:space="preserve">. </s> <s xml:id="echoid-s6232" xml:space="preserve">. </s> <s xml:id="echoid-s6233" xml:space="preserve">. </s> <s xml:id="echoid-s6234" xml:space="preserve">2400</s> </p> <p style="it"> <s xml:id="echoid-s6235" xml:space="preserve"><emph style="sc">Total</emph> du contenu de cet Abregé. </s> <s xml:id="echoid-s6236" xml:space="preserve">. </s> <s xml:id="echoid-s6237" xml:space="preserve">. </s> <s xml:id="echoid-s6238" xml:space="preserve">. </s> <s xml:id="echoid-s6239" xml:space="preserve">42700 l.</s> <s xml:id="echoid-s6240" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6241" xml:space="preserve">C’eſt ainſi, qu’il faudra faire les Abregés, leſquels ne differeront <lb/>des Etats arrêtés des Dépenſes annuelles que du titre ſeulement; <lb/></s> <s xml:id="echoid-s6242" xml:space="preserve">c’eſt dans cet Abregé que le Miniſtre choiſira les articles pour <lb/>leſquels on veut faire fonds, enſuite dequoi on les ſépare de l’Eſti-<lb/>mation pour en faire un autre à part qui ſera l’Etat de la Dépenſe.</s> </p> <p> <s xml:id="echoid-s6243" xml:space="preserve">Depuis que Mr. </s> <s xml:id="echoid-s6244" xml:space="preserve">le Marêchal de Vauban a donné les Reglemens <lb/>que l’on vient de voir, les Ingenieurs s’y ſont conformés à peu <lb/>de choſes près. </s> <s xml:id="echoid-s6245" xml:space="preserve">Il y a pourtant des Directions où on ne ſuit pas tout <lb/>à fait le même arrangement; </s> <s xml:id="echoid-s6246" xml:space="preserve">& </s> <s xml:id="echoid-s6247" xml:space="preserve">c’eſt pour ne point adopter ce qui <lb/>ſe fait dans l’une plûtôt que dans l’autre, que j’airaporté à la lettre les <lb/>Inſtructions de Mr. </s> <s xml:id="echoid-s6248" xml:space="preserve">de Vauban preferablement à celles que j’aurois <lb/>pû prendre ailleurs: </s> <s xml:id="echoid-s6249" xml:space="preserve">au reſte, il n’y a perſonne qui neſe mette en très-<lb/>peu de tems au fait de toutes ces minuties, puiſqu’il ſuffira de lire <lb/>ou de copier les Etats & </s> <s xml:id="echoid-s6250" xml:space="preserve">Memoires qui ſe font dans les places pen-<lb/>dant le cours d’une année; </s> <s xml:id="echoid-s6251" xml:space="preserve">je les aurois même ſuprimés, ſi les moin-<lb/>dres choſes ne meritoient toûjours attention quand on neles ſait pas: </s> <s xml:id="echoid-s6252" xml:space="preserve"><lb/>il eſt vray, que des petits détails trop répetés ennuyent les habiles <lb/>gens, qui n’y trouvent rien que d’inſipide; </s> <s xml:id="echoid-s6253" xml:space="preserve">mais, je les prie de conſi-<lb/>dérer, qu’un Livre comme celui-ci n’eſt pas fait pour eux.</s> <s xml:id="echoid-s6254" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div301" type="section" level="2" n="99"> <head xml:id="echoid-head240" style="it" xml:space="preserve">Fin du troiſiéme Livre.</head> <pb file="0285" n="296"/> <figure> <image file="0285-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0285-01"/> </figure> </div> <div xml:id="echoid-div302" type="section" level="2" n="100"> <head xml:id="echoid-head241" xml:space="preserve">LA SCIENCE <lb/>DES INGENIEURS <lb/>DANS LA CONDUITE DES TRAVAUX <lb/>DE FORTIFICATION.</head> <head xml:id="echoid-head242" xml:space="preserve">LIVRE QUATRIE’ME.</head> <head xml:id="echoid-head243" style="it" xml:space="preserve">Qui traite de la Conſtruction des Edifices militaires & civils.</head> <p> <s xml:id="echoid-s6255" xml:space="preserve">L’ON vient d’enſeigner dans le Livre précedent la <lb/>Conſtruction des gros Ouvrages de Fortification, <lb/>avec tous les détails auſquels il falloit avoir égard: </s> <s xml:id="echoid-s6256" xml:space="preserve">on <lb/>trouvera dans celui-ci les Edifices qui ſe font aux <lb/>Places de Guerre, leur proprieté, la maniere deles <lb/>bâtir ſolidement, & </s> <s xml:id="echoid-s6257" xml:space="preserve">une ſuite de nouveaux détails <lb/>qui plairont peut-être à ceux qui ont interêt de ſe les rendre fami-<lb/>liers; </s> <s xml:id="echoid-s6258" xml:space="preserve">& </s> <s xml:id="echoid-s6259" xml:space="preserve">comme l’experience dans l’art de bâtir eſt la regle que <lb/>l’on peut ſuivre avec plus d’aſſurance, principalement quand on <lb/>n’a qu’à imiter les ouvrages qui ont déja été executés avec ſuc- <pb o="2" file="0286" n="297" rhead="LA SCIENCE DES INGENIEURS,"/> cés, j’ai crû que le parti le plus ſûr étoit de raporter exactement <lb/>les plans, profils, & </s> <s xml:id="echoid-s6260" xml:space="preserve">élevations, des édifices les plus aprouvés, qui <lb/>ont été faits dans les places neuves: </s> <s xml:id="echoid-s6261" xml:space="preserve">car comme ceux, qui en ont <lb/>donné les projets, peuvent paſſer avec raiſon pour les maîtres de <lb/>l’art, il eſt à preſumer qu’ils ont fait ce qui ſe pouvoit de mieux, <lb/>& </s> <s xml:id="echoid-s6262" xml:space="preserve">qu’on ne peut s’écarter en ſuivant leurs modelles; </s> <s xml:id="echoid-s6263" xml:space="preserve">laiſſant à la <lb/>prudence de ceux qui les feront conſtruire, de faire les change-<lb/>mens qu’ils jugeront à propos.</s> <s xml:id="echoid-s6264" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6265" xml:space="preserve">Comme la Maçonnerie a été expliquée aſſez amplement dans <lb/>le troiſiéme Livre, je ne m’y arrêterai guere dans celui-ci, parce <lb/>que l’on trouvera dans le ſixieme des devis, qui ne laiſſeront rien <lb/>à deſirer pour la conſtruction des ouvrages qui demandent d’être <lb/>travaillés avec ſoin; </s> <s xml:id="echoid-s6266" xml:space="preserve">& </s> <s xml:id="echoid-s6267" xml:space="preserve">je ferai enſorte que toutes les matieres <lb/>ſoient ſi bien liées, que, ſans faire des repetitions inutiles, l’on puiſ-<lb/>ſe trouver dans une partie ce qui ſemble manquer à l’autre: </s> <s xml:id="echoid-s6268" xml:space="preserve">n’a-<lb/>yant pas fait mention juſqu’ici des qualités du bois qui s’employe <lb/>dans la charpente, des précautions qu’il faut prendre pour le met-<lb/>tre en œuvre, & </s> <s xml:id="echoid-s6269" xml:space="preserve">comme on peut en eſtimer la force ou la reſiſtan-<lb/>ce, je commencerai d’abord par examiner toutes ces choſes, en-<lb/>ſuite j’en uſerai de même pour le fer; </s> <s xml:id="echoid-s6270" xml:space="preserve">puiſque ces deux matieres, <lb/>après la maçonnerie, ſont ce qu’il y a de plus eſſentiel dans la conſ-<lb/>truction des édifices: </s> <s xml:id="echoid-s6271" xml:space="preserve">enfin, je finirai ce quatriéme Livre par les <lb/>Maximes genérales que l’on doit ſuivre dans l’Architecture civile, <lb/>pour de-là paſſer au cinquiéme, où l’on trouvera tout ce qui peut <lb/>apartenir à la decoration des mêmes édifices, afin d’être égale-<lb/>ment inſtruit du ſolide & </s> <s xml:id="echoid-s6272" xml:space="preserve">de l’agreable.</s> <s xml:id="echoid-s6273" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div303" type="section" level="2" n="101"> <head xml:id="echoid-head244" xml:space="preserve">CHAPITRE PREMIER.</head> <head xml:id="echoid-head245" style="it" xml:space="preserve">Des qualités du bois qui entre dans la charpente.</head> <p> <s xml:id="echoid-s6274" xml:space="preserve">LE meilleur bois, qu’on puiſſe employer dans les édifices, eſt <lb/>celui de chêne; </s> <s xml:id="echoid-s6275" xml:space="preserve">parce qu’étant fort dur, il reſiſte mieux que <lb/>tout autre au fardeau, & </s> <s xml:id="echoid-s6276" xml:space="preserve">ſe conſerve plus long-tems en bon état, <lb/>n’étant point ſi ſujet à ſe pourrir par l’humidité: </s> <s xml:id="echoid-s6277" xml:space="preserve">il ſe conſerve mê-<lb/>me dans l’eau des tems infinis, où il acquiert une ſi grande dure-<lb/>té, qu’il n’eſt preſque pas poſſible de le travailler avec les outils; <lb/></s> <s xml:id="echoid-s6278" xml:space="preserve">c’eſt ce que l’on a remarqué pluſieurs fois aux pilots que l’on <pb o="3" file="0287" n="298" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> a trouvez ſous de vieilles demolitions des ouvrages bâtis par les <lb/>Romains.</s> <s xml:id="echoid-s6279" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6280" xml:space="preserve">Autrefois l’on ſe ſervoit de chatenier, dans les édifices conſide-<lb/>rables, parce que l’on ignoroit la bonté du chêne; </s> <s xml:id="echoid-s6281" xml:space="preserve">mais, l’on eſt <lb/>revenu de cette erreur, depuis environ 150. </s> <s xml:id="echoid-s6282" xml:space="preserve">ans, parce que le <lb/>chatenier eſt ſujet à ſe fendre, & </s> <s xml:id="echoid-s6283" xml:space="preserve">à ſe pourrir, quand il eſt aſſis <lb/>dans la maçonnerie, comme il arrive aux extremitez des poutres, <lb/>qui ſont dans les pignons, ce qui oblige par la ſuite à en mettre <lb/>de nouvelles; </s> <s xml:id="echoid-s6284" xml:space="preserve">au lieu que celles de chêne ſe conſervent en bon <lb/>état, des ſept ou huit cens ans, quand on a pris, avant de les couper <lb/>dans les forêts, toutes les précautions, dont nous parlerons dans <lb/>la ſuite.</s> <s xml:id="echoid-s6285" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6286" xml:space="preserve">L’orme eſt auſſi un bon bois; </s> <s xml:id="echoid-s6287" xml:space="preserve">mais on s’en ſert rarement pour <lb/>la charpente, parce que n’étant pas commun, on aime mieux le <lb/>garder pour d’autres uſages: </s> <s xml:id="echoid-s6288" xml:space="preserve">on en fait des verrains, des moyeux, <lb/>des jantes de rouës, ſoit de moulin ou de voiture, parce qu’il ſe <lb/>travaille bien, étant liant & </s> <s xml:id="echoid-s6289" xml:space="preserve">point ſujet à s’éclater; </s> <s xml:id="echoid-s6290" xml:space="preserve">ce qui fait <lb/>qu’on l’employe preferablement à tout autre, dans l’artillerie, pour <lb/>la conſtruction des afuts.</s> <s xml:id="echoid-s6291" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6292" xml:space="preserve">Le ſapin eſt auſſi d’uſage dans les édifices, quand on eſt à por-<lb/>tée d’en avoir à juſte prix, pour des ſolivaux & </s> <s xml:id="echoid-s6293" xml:space="preserve">des planchers: </s> <s xml:id="echoid-s6294" xml:space="preserve">on <lb/>en diſtingue de deux ſortes, le ſapin ordinaire, & </s> <s xml:id="echoid-s6295" xml:space="preserve">le ſapin rouge; <lb/></s> <s xml:id="echoid-s6296" xml:space="preserve">ce dernier eſt le meilleur, parce qu’il ne ſe caſſe pas ſi aiſément que <lb/>l’autre: </s> <s xml:id="echoid-s6297" xml:space="preserve">on s’en ſert aſſés ſouvent pour des palplanches, dans la <lb/>conſtruction des Ecluſes, & </s> <s xml:id="echoid-s6298" xml:space="preserve">pour les petits grillages qui ſont au-deſſus <lb/>des faſcinages des jettées, ſe conſervant bien dans l’eau; </s> <s xml:id="echoid-s6299" xml:space="preserve">cependant, <lb/>il n’eſt pas trop bon pour les bâtimens, parce qu’il eſt ſujet à s’échau-<lb/>fer, & </s> <s xml:id="echoid-s6300" xml:space="preserve">à engendrer des vers qui le gâtent.</s> <s xml:id="echoid-s6301" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6302" xml:space="preserve">Je paſſe ſous ſilence pluſieurs autres eſpeces de bois, dont on <lb/>ne ſe ſert point ordinairement pour la charpente, ſoit que les uns <lb/>n’y conviennent point à cauſe de leurs mauvaiſes qualités, ou que <lb/>les autres ſoient rares, & </s> <s xml:id="echoid-s6303" xml:space="preserve">d’un prix qui les fait reſerver pour des <lb/>meubles ou d’autres emplois qui n’ont point de raport à mon ſujet.</s> <s xml:id="echoid-s6304" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6305" xml:space="preserve">Les arbres, de quelque eſpece qu’ils ſoient, participent toûjours <lb/>de la nature du terrain où ils ſont crûs: </s> <s xml:id="echoid-s6306" xml:space="preserve">ceux qui viennent dans <lb/>un lieu aride, pierreux, ou ſablonneux, ſont ordinairement durs & </s> <s xml:id="echoid-s6307" xml:space="preserve"><lb/>d’un fort bon emploi; </s> <s xml:id="echoid-s6308" xml:space="preserve">au contraire, s’ils ſont venus dans un lieu bas & </s> <s xml:id="echoid-s6309" xml:space="preserve"><lb/>aquatique, ils ne ſont pas d’une auſſi bonne qualité, étant plus ten-<lb/>dres, & </s> <s xml:id="echoid-s6310" xml:space="preserve">moins propres à ſoutenir de grands fardeaux; </s> <s xml:id="echoid-s6311" xml:space="preserve">mais en re-<lb/>compenſe ils ſe travaillent mieux pour les ouvrages de menuiſerie, <lb/>au lieu que les autres, par leur dureté, ſont rebelles aux outils:</s> <s xml:id="echoid-s6312" xml:space="preserve"> <pb o="4" file="0288" n="299" rhead="LA SCIENCE DES INGENIEURS,"/> ceux, qui viennent du côté du midi, ſont meilleurs que ceux du <lb/>côté du couchant, le ſoleil contribuant beaucoup à les rendre plus <lb/>durs, plus hauts, & </s> <s xml:id="echoid-s6313" xml:space="preserve">plus gros; </s> <s xml:id="echoid-s6314" xml:space="preserve">d’ailleurs, ils n’ont que très peu d’au-<lb/>bier, qui eſt une partie de l’arbre immediatement ſous l’écorce, <lb/>plus tendre que le reſte, qu’on peut regarder comme la matiere <lb/>dont l’arbre s’eſt augmenté depuis peu de tems, parce que tous les <lb/>ans la ſeve commence au printems à former un nouvel aubier, <lb/>qui va toûjours en croiſſant juſqu’à la chûte des feuilles, & </s> <s xml:id="echoid-s6315" xml:space="preserve">fe dur-<lb/>cit enſuite pendant l’hiver, pour ſe joindre au corps de l’arbre, par-<lb/>ce qu’alors le froid fait reſerrer les pores, qui ne recevant plus le <lb/>ſuc qui s’y introduiſoit, l’arbre reſte comme s’il étoit mort; </s> <s xml:id="echoid-s6316" xml:space="preserve">mais <lb/>quand la terre vient à s’échaufer au printems, la nature forme en-<lb/>core un nouvel aubier, & </s> <s xml:id="echoid-s6317" xml:space="preserve">tous les ans il arrive la même choſe, <lb/>juſqu’à ce qu’il commence à dépérir par la vieilleſſe.</s> <s xml:id="echoid-s6318" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6319" xml:space="preserve">Il eſt encore à remarquer, que les arbres, qui croiſſent éloignés <lb/>les uns des autres, & </s> <s xml:id="echoid-s6320" xml:space="preserve">qui ſont battus par les vents, comme ſont <lb/>ceux qui viennent ſur la rive ou le bord des forêts, ſont ordinai-<lb/>rement plus durs & </s> <s xml:id="echoid-s6321" xml:space="preserve">plus forts que les autres, qui viennent dans des <lb/>lieux ſerrés, où les vents ne penetrent point; </s> <s xml:id="echoid-s6322" xml:space="preserve">les premiers reſſem-<lb/>blans aux hommes qui ſe fortifient par l’exercice & </s> <s xml:id="echoid-s6323" xml:space="preserve">le travail: </s> <s xml:id="echoid-s6324" xml:space="preserve">quant <lb/>à la qualité des arbres en general, les meilleurs ſont ceux qui ſont <lb/>bien ſains, qui ont un droit fil, qui ne ſont point roullés, rabou-<lb/>gris, ni geliffes, & </s> <s xml:id="echoid-s6325" xml:space="preserve">qui n’ont ni fentes ni gerſures.</s> <s xml:id="echoid-s6326" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6327" xml:space="preserve">L’on peut abattre le chêne depuis 60. </s> <s xml:id="echoid-s6328" xml:space="preserve">juſqu’à 200. </s> <s xml:id="echoid-s6329" xml:space="preserve">ans, parce <lb/>que devant qu’il ait 60. </s> <s xml:id="echoid-s6330" xml:space="preserve">ans il eſt trop jeune, & </s> <s xml:id="echoid-s6331" xml:space="preserve">n’a point aſſés de <lb/>force, & </s> <s xml:id="echoid-s6332" xml:space="preserve">qu’après 200. </s> <s xml:id="echoid-s6333" xml:space="preserve">ans, il deperit & </s> <s xml:id="echoid-s6334" xml:space="preserve">ne ſe conſerve pas ſi long-<lb/>tems étant employé: </s> <s xml:id="echoid-s6335" xml:space="preserve">l’âge le plus convenable, pour le couper dans <lb/>toute ſa force, eſt autour de 100. </s> <s xml:id="echoid-s6336" xml:space="preserve">ans.</s> <s xml:id="echoid-s6337" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6338" xml:space="preserve">On dit communement, que le bois croît pendant 100. </s> <s xml:id="echoid-s6339" xml:space="preserve">ans, s’en-<lb/>tretient 100. </s> <s xml:id="echoid-s6340" xml:space="preserve">ans, & </s> <s xml:id="echoid-s6341" xml:space="preserve">enſuite eſt 100. </s> <s xml:id="echoid-s6342" xml:space="preserve">ans à deperir: </s> <s xml:id="echoid-s6343" xml:space="preserve">il eſt vrai, qu’au <lb/>bout de 200. </s> <s xml:id="echoid-s6344" xml:space="preserve">ans, un arbre deperit; </s> <s xml:id="echoid-s6345" xml:space="preserve">mais c’eſt une erreur de croi-<lb/>re qu’après 100. </s> <s xml:id="echoid-s6346" xml:space="preserve">ans, il reſte 100. </s> <s xml:id="echoid-s6347" xml:space="preserve">autres années dans une eſpece <lb/>d’inaction, puiſque, tandis qu’on s’imagine qu’il ne fait que s’entre-<lb/>tenir, il augmente en groſſeur juſqu’à 160. </s> <s xml:id="echoid-s6348" xml:space="preserve">& </s> <s xml:id="echoid-s6349" xml:space="preserve">180. </s> <s xml:id="echoid-s6350" xml:space="preserve">ans, comme <lb/>il eſt aiſé de s’en apercevoir quand il eſt abattu; </s> <s xml:id="echoid-s6351" xml:space="preserve">il eſt bien vrai <lb/>qu’après 100. </s> <s xml:id="echoid-s6352" xml:space="preserve">ans un arbre n’augmente plus guere en hauteur; </s> <s xml:id="echoid-s6353" xml:space="preserve">mais <lb/>cela ne l’empêche pas de groſſir, puiſqu’il prend encore de la <lb/>nourriture: </s> <s xml:id="echoid-s6354" xml:space="preserve">car tout bois, qui porte des feuilles, a de la ſéve, & </s> <s xml:id="echoid-s6355" xml:space="preserve"><lb/>tout ce qui a de la ſéve doit profiter; </s> <s xml:id="echoid-s6356" xml:space="preserve">au lieu que ſi la croiſſance <lb/>d’un arbre ne duroit que pendant un ſiécle, il ne marqueroit plus <lb/>après ce tems aucune nouvelle augmentation, ce qui eſt contraire <lb/>à l’experience.</s> <s xml:id="echoid-s6357" xml:space="preserve"/> </p> <pb o="5" file="0289" n="300" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s6358" xml:space="preserve">Si l’on veut ſavoir quel àge a un bois taillis ou futaye, on n’a <lb/>qu’à le couper par le pied, & </s> <s xml:id="echoid-s6359" xml:space="preserve">on apercevra un nombre de circon-<lb/>ferences preſque concentriques, qui vont come en progreſſion <lb/>depuis le centre de l’arbre juſqu’à l’écorce, qui marquent aſſez diſ-<lb/>tinctement le nombre des croiſſances, & </s> <s xml:id="echoid-s6360" xml:space="preserve">par conſequent celui <lb/>des années.</s> <s xml:id="echoid-s6361" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6362" xml:space="preserve">Le tems le plus propre pour abattre les arbres eſt depuis le <lb/>mois d’Octobre juſqu’au commencement de Mars; </s> <s xml:id="echoid-s6363" xml:space="preserve">parce qu’alors <lb/>la ſéve n’eſt guere en action, & </s> <s xml:id="echoid-s6364" xml:space="preserve">les pores ſont plus reſerrés. </s> <s xml:id="echoid-s6365" xml:space="preserve">L’on <lb/>obſerve auſſi d’en faire la coupe dans le dernier quartier de la <lb/>lune, parce qu’on prétend qu’il y a plus ou moins d’humidité <lb/>dans les pores, ſelon que la lune croît ou decline: </s> <s xml:id="echoid-s6366" xml:space="preserve">la maniere de <lb/>les couper, quand on veut prendre toutes les meſures neceſſaires, <lb/>eſt de les cerner par le pied, juſqu’à la moitié du cœur, & </s> <s xml:id="echoid-s6367" xml:space="preserve">les <lb/>laiſſer ainſi quelque-tems, afin que la ſéve, coulant par cette en-<lb/>taille au travers de l’aubier, ne ſe corrompe point dans le bois.</s> <s xml:id="echoid-s6368" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6369" xml:space="preserve">Comme tous les jours on achette des bois abattus, il faut, pour <lb/>ne pas y être trompé, les ſonder auparavant, afin que, s’ils pêchent <lb/>en quelque choſe, on puiſſe au moins en faire l’uſage qui leur eſt <lb/>le plus naturel: </s> <s xml:id="echoid-s6370" xml:space="preserve">pour cela on répand, dans un des bouts de l’arbre, <lb/>un peu d’huile d’olive bien chaude, pour connoître ce qu’il eſt; <lb/></s> <s xml:id="echoid-s6371" xml:space="preserve">car s’il eſt venu dans un fonds marecageux, le ſel de l’arbre étant <lb/>acre, l’huile greſillera en la jettant; </s> <s xml:id="echoid-s6372" xml:space="preserve">s’il eſt venu dans un terrain <lb/>doux, & </s> <s xml:id="echoid-s6373" xml:space="preserve">qu’il ait été coupé en tems de ſéve, l’huile ne s’imbibera <lb/>pas entierement par-tout, il en reſtera vers les bords; </s> <s xml:id="echoid-s6374" xml:space="preserve">au contrai-<lb/>re, s’il eſt crû dans un lieu ſec, & </s> <s xml:id="echoid-s6375" xml:space="preserve">qu’il ait été coupé dans le tems <lb/>que la ſéve eſt amortie, l’huile s’y imbibera toute entiere, & </s> <s xml:id="echoid-s6376" xml:space="preserve">ſe <lb/>ſêchera ſur le champ: </s> <s xml:id="echoid-s6377" xml:space="preserve">prevenu de cela, il faudra prendre garde <lb/>de ne point employer celui qui ſera crû dans un lieu marecageux, <lb/>aux endroits humides ou expoſés à la pluye, parce qu’il s’y pour-<lb/>riroit en peu de tems: </s> <s xml:id="echoid-s6378" xml:space="preserve">il eſt également dangereux de le mettre où <lb/>il regne un grand ſoleil; </s> <s xml:id="echoid-s6379" xml:space="preserve">car la chaleur, ſurprenant l’humidité dont <lb/>il eſt rempli, l’ouvre & </s> <s xml:id="echoid-s6380" xml:space="preserve">le fait fendre, comme on le remarque tous <lb/>les jours, non ſeulement aux ouvrages de charpente qui ſont <lb/>expoſés à l’air, mais même à ceux qui ſont à couvert. </s> <s xml:id="echoid-s6381" xml:space="preserve">Quand on <lb/>en veut témoigner quelque mécontentement aux Entrepreneurs <lb/>ou aux Charpentiers, ils répondent que c’eſt un effet de la for-<lb/>ce du bois; </s> <s xml:id="echoid-s6382" xml:space="preserve">&</s> <s xml:id="echoid-s6383" xml:space="preserve">, ſoit par ignorance ou par malice, ils ſe tirent <lb/>d’affaire avec ce ſot raiſonnement. </s> <s xml:id="echoid-s6384" xml:space="preserve">Cependant, comme l’on eſt <lb/>ſouvent contraint d’employer des bois de bonne & </s> <s xml:id="echoid-s6385" xml:space="preserve">mauvaiſe qua-<lb/>lité, il faudra choiſir le meilleur, c’eſt-à-dire, le moins humi- <pb o="6" file="0290" n="301" rhead="LA SCIENCE DES INGENIEURS,"/> de, pour le placer dans les lieux les plus conſiderables de l’é-<lb/>difice, & </s> <s xml:id="echoid-s6386" xml:space="preserve">l’autre aux endroits de peu de conſequence, faiſant at-<lb/>tention que les gros bois étant vitieux ſont plus ſujets à ſe fendre <lb/>& </s> <s xml:id="echoid-s6387" xml:space="preserve">à éclater que les plus menus: </s> <s xml:id="echoid-s6388" xml:space="preserve">il eſt à propos de ne faire les pou-<lb/>tres qu’avec ce qu’on aura de meilleur, afin que par la ſuite, ſi <lb/>on eſt contraint de renouveller quelque piece de charpente, on <lb/>ne ſoit pas obligé à une grande dépenſe, & </s> <s xml:id="echoid-s6389" xml:space="preserve">à un travail conſide-<lb/>rable.</s> <s xml:id="echoid-s6390" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6391" xml:space="preserve">Il arrive ſouvent qu’une piece de bois, après avoir été équarrie, <lb/>paroît bien ſaine, tandis que le cœur en eſt gâté: </s> <s xml:id="echoid-s6392" xml:space="preserve">pour ne pas y <lb/>être trompé, il faut faire donner des coups de marteau à l’un des <lb/>bouts, & </s> <s xml:id="echoid-s6393" xml:space="preserve">porter l’oreille à l’autre; </s> <s xml:id="echoid-s6394" xml:space="preserve">ſi on entend un bruit ſourd & </s> <s xml:id="echoid-s6395" xml:space="preserve"><lb/>caſſé, c’eſt une marque que la piece eſt gâtée; </s> <s xml:id="echoid-s6396" xml:space="preserve">au contraire, ſi le ſon <lb/>eſt clair, c’eſt une preuve qu’elle eſt bonne.</s> <s xml:id="echoid-s6397" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6398" xml:space="preserve">J’ai encore à faire remarquer, que quand on peut garder à cou-<lb/>vert quelque tems les bois avant de les debiter, ils en ſont d’un <lb/>bien meilleur uſage, parce que s’ils ſont crus dans un endroit hu-<lb/>mide, ils ſont moins ſujets à ſe dejetter & </s> <s xml:id="echoid-s6399" xml:space="preserve">à ſe fendre; </s> <s xml:id="echoid-s6400" xml:space="preserve">ainſi je vou-<lb/>drois qu’on les gardât au moins deux ans, pour qu’ils ayent le <lb/>tems de s’affermir & </s> <s xml:id="echoid-s6401" xml:space="preserve">de ſe conſolider: </s> <s xml:id="echoid-s6402" xml:space="preserve">s’il s’agit des ouvrages de <lb/>menuiſerie, il faudra les garder bien davantage; </s> <s xml:id="echoid-s6403" xml:space="preserve">puiſque, quand <lb/>on ne les employeroit qu’au bout de cinq ou ſix ans, l’ouvrage <lb/>n’en ſeroit que meilleur.</s> <s xml:id="echoid-s6404" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6405" xml:space="preserve">Une précaution encore très neceſſaire, dans l’uſage journalier <lb/>des bois, eſt de ne les employer qu’après en avoir détaché l’au-<lb/>bier; </s> <s xml:id="echoid-s6406" xml:space="preserve">car pour peu qu’il en reſte dans les flages, après même qu’ils <lb/>ont été équarris, il eſt certain qu’il en occaſionnera la pourriture, <lb/>ou qu’il s’y engendrera des vers.</s> <s xml:id="echoid-s6407" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6408" xml:space="preserve">D’habiles gens prétendent, que les vers qui s’engendrent dans <lb/>le bois, ne viennent point de la ſubſtance du bois même; </s> <s xml:id="echoid-s6409" xml:space="preserve">mais <lb/>que ce ſont des œufs, que les vers depoſent dans la terre, que la <lb/>ſéve introduit dans les pores, où, venant à éclore après un certain <lb/>tems, ils produiſent les vers que l’on y voit, quand il eſtſec: </s> <s xml:id="echoid-s6410" xml:space="preserve">le rap-<lb/>port qu’il y a de cette hypotheſe, avec ce que l’on obſerve tous <lb/>les jours, la rend aſſés plauſible; </s> <s xml:id="echoid-s6411" xml:space="preserve">car les bois, quiſont ſujets à être <lb/>vermoulus, commencent à ſe gâter par l’aubier, quand on y en a <lb/>laiſſé en les équarriſſant, & </s> <s xml:id="echoid-s6412" xml:space="preserve">plus l’aubier eſt conſiderable, & </s> <s xml:id="echoid-s6413" xml:space="preserve">plus <lb/>les vers y croiſſent en abondance: </s> <s xml:id="echoid-s6414" xml:space="preserve">& </s> <s xml:id="echoid-s6415" xml:space="preserve">comme les bois, qui ont <lb/>beaucoup d’aubier, viennent ordinairement dans des lieux humi-<lb/>des, où les vers ſont en plus grand nombre que dans le terrain <lb/>ſec, il n’eſt donc pas ſurprenant qu’ils ſoient plus ſujets à cet in-<lb/>convenient que les autres.</s> <s xml:id="echoid-s6416" xml:space="preserve"/> </p> <pb o="7" file="0291" n="302" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s6417" xml:space="preserve">D’autres attribuent cette croiſſance des vers dans le bois à une <lb/>cauſe differente: </s> <s xml:id="echoid-s6418" xml:space="preserve">les mouches, diſent-ils, font des œufs, ces œufs <lb/>produiſent des vers, qui ſe nourriſſent & </s> <s xml:id="echoid-s6419" xml:space="preserve">croiſſent. </s> <s xml:id="echoid-s6420" xml:space="preserve">Or les mouches <lb/>piquent le fruit qui leur convient, & </s> <s xml:id="echoid-s6421" xml:space="preserve">y depoſent un œuf, qui <lb/>forme le ver dont le fruit eſt mangé: </s> <s xml:id="echoid-s6422" xml:space="preserve">ainſi, ne peut-il pas arriver <lb/>qu’elles faſſent la même choſe dans les arbres, & </s> <s xml:id="echoid-s6423" xml:space="preserve">dans le bois ten-<lb/>dre, comme eſt celui qui croit dans les lieux humides, & </s> <s xml:id="echoid-s6424" xml:space="preserve">dont <lb/>l’aubier eſt aiſé à penetrer?</s> <s xml:id="echoid-s6425" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6426" xml:space="preserve">Le bois, quoique bon, ſe gâte quelquefois, lors qu’étant roulé <lb/>il a été mis en œuvre, ce qui ſe connoît par les rognes ou mouſ-<lb/>ſes qu’il jette en dehors, qui reſſemblent aſſés à des champignons <lb/>ou à des mouſſerons.</s> <s xml:id="echoid-s6427" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6428" xml:space="preserve">Quand il eſt échauffé, il eſt encore fujet à un autre défaut, qui <lb/>eſt de ſe couvrir par la ſuite de petites taches blanches, noires, <lb/>& </s> <s xml:id="echoid-s6429" xml:space="preserve">rouſſes, ce qui le fait paroître pourri; </s> <s xml:id="echoid-s6430" xml:space="preserve">mais ce qu’il y a de ſur-<lb/>prenant, c’eſt qu’un bois tel ſain qu’il ſoit, apliqué contre un au-<lb/>tre qui a les défauts dont nous venons de parler, participe lui-mê-<lb/>me de ces defauts au bout d’un certain tems: </s> <s xml:id="echoid-s6431" xml:space="preserve">c’eſt pourquoi il faut <lb/>prendre garde dans l’employ qu’on en fera, qu’il ne touche rien <lb/>qui puiſſe l’endommager, faire même enſorte que les pieces con-<lb/>ſiderables, comme les poutres, ne touchent jamais le mortier ni le <lb/>plâtre, parce que ces matieres les échauffent; </s> <s xml:id="echoid-s6432" xml:space="preserve">il ſeroit même à pro-<lb/>pos de laiſſer quelques petits trous dans les murs, à l’extremité des <lb/>poutres, afin que l’air du dehors puiſſe les rafraichir.</s> <s xml:id="echoid-s6433" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div304" type="section" level="2" n="102"> <head xml:id="echoid-head246" xml:space="preserve">CHAPITRE SECOND.</head> <head xml:id="echoid-head247" style="it" xml:space="preserve">Où l’on fait voir la maniere de calculer, ou d’eſtimer la for-<lb/>ce des principales pieces de Charpente, qui s’employent <lb/>dans les Bâtimens.</head> <p> <s xml:id="echoid-s6434" xml:space="preserve">DEpuis que j’ai commencé à m’apliquer à l’Architecture, la <lb/>maçonnerie & </s> <s xml:id="echoid-s6435" xml:space="preserve">la charpente m’ont toûjours paru dignes d’u-<lb/>ne étude particuliere: </s> <s xml:id="echoid-s6436" xml:space="preserve">& </s> <s xml:id="echoid-s6437" xml:space="preserve">après m’être ſatisfait ſur la mécanique de <lb/>la maçonnerie, j’ai conſideré qu’on n’avoit aucune regle pour dé-<lb/>terminer la reſiſtance des pieces de charpente, qui ſont ſujettes à <lb/>être chargées par des fardeaux conſiderables, & </s> <s xml:id="echoid-s6438" xml:space="preserve">que par conſe-<lb/>quent on ignoroit le poids que pouvoient porter les planchers des <lb/>Arſenaux, ceux des Magaſins pour les vivres, &</s> <s xml:id="echoid-s6439" xml:space="preserve">c. </s> <s xml:id="echoid-s6440" xml:space="preserve">pour ne pas <pb o="8" file="0292" n="303" rhead="LA SCIENCE DES INGENIEURS,"/> aprehender de les rompre; </s> <s xml:id="echoid-s6441" xml:space="preserve">puis qu’excepté Mr. </s> <s xml:id="echoid-s6442" xml:space="preserve">Parent, qui a par-<lb/>lé de la reſiſtance des bois, dans les Memoires de l’Academie <lb/>Royale des Sciences, (mais d’une maniere un peu trop élegante <lb/>pour être entendu de tout le monde,) je ne ſache perſonne qui <lb/>en ait écrit: </s> <s xml:id="echoid-s6443" xml:space="preserve">car je compte pour rien les proportions que quel-<lb/>ques Architectes ont données, pour les poutres & </s> <s xml:id="echoid-s6444" xml:space="preserve">ſolives ſelon <lb/>leur portée; </s> <s xml:id="echoid-s6445" xml:space="preserve">ayant pour maxime de ne rien admettre, qui ne ſoit <lb/>démontré, ou au moins expliqué par un raiſonnement, qui faſſe va-<lb/>loir ce qu’on propoſe. </s> <s xml:id="echoid-s6446" xml:space="preserve">Il ſeroit bien à ſouhaiter qu’on eût toû-<lb/>jours eu cette delicateſſe dans l’Architecture; </s> <s xml:id="echoid-s6447" xml:space="preserve">elle ſeroit aujour-<lb/>d’hui à un point de perfection, auquel ſelon toute aparence elle <lb/>n’arrivera pas ſi-tôt, ſi on ne s’y prend pas autrement que l’on n’a <lb/>fait juſqu’ici, je veux dire tant qu’elle ſera abandonnée au capri-<lb/>ce de quiconque veut s’en mêler.</s> <s xml:id="echoid-s6448" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6449" xml:space="preserve">Comme il étoit neceſſaire de joindre à la theorie, des expe-<lb/>riences ſur la force des bois qui ſont le plus en uſage dans les bâ-<lb/>timens, j’en ai fait un grand nombre dont je raporterai le détail, <lb/>parce qu’enſuite elles nous ſerviront à établir des regles généra-<lb/>les, qu’il ſera aiſé d’apliquer dans toute ſorte de cas; </s> <s xml:id="echoid-s6450" xml:space="preserve">mais, avant <lb/>d’en venir-là, il eſt à propos d’inſinuer quelques principes dont il <lb/>eſt neceſſaire qu’on ſoit prevenû.</s> <s xml:id="echoid-s6451" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div305" type="section" level="2" n="103"> <head xml:id="echoid-head248" style="it" xml:space="preserve">Principes ſur la reſiſtance du bois en general.</head> <p> <s xml:id="echoid-s6452" xml:space="preserve">On ſupoſe qu’on a une planche EDFG, poſée de cant ſur un <lb/> <anchor type="note" xlink:label="note-0292-01a" xlink:href="note-0292-01"/> point d’apui K, qui répond au milieu A, de la longueur, que cet-<lb/>te planche eſt extrêmement mince, afin de faire abſtraction de <lb/> <anchor type="note" xlink:label="note-0292-02a" xlink:href="note-0292-02"/> ſon épaiſſeur, & </s> <s xml:id="echoid-s6453" xml:space="preserve">qu’à chacune de ſes extrêmités DE, & </s> <s xml:id="echoid-s6454" xml:space="preserve">FG, il y <lb/>a une puiſſance qui agit de haut en bas pour la rompre: </s> <s xml:id="echoid-s6455" xml:space="preserve">cela po-<lb/>ſé, il eſt conſtant que, dès que les deux puiſſances apuyeront égale-<lb/>ment, la planche commencera un peu à ſe courber, parce que <lb/>les fibres du milieu s’alongeront, les uns plus les autres moins, & </s> <s xml:id="echoid-s6456" xml:space="preserve"><lb/>ſeront tendus dans la proportion de leur diſtance du point d’apui. <lb/></s> <s xml:id="echoid-s6457" xml:space="preserve">Or ſi l’on conçoit la ligne BA, ou CA, diviſée en un grand nom-<lb/>bre de parties égales, & </s> <s xml:id="echoid-s6458" xml:space="preserve">que chaque point de diviſion réponde à <lb/>un fibre; </s> <s xml:id="echoid-s6459" xml:space="preserve">tous ces fibres ſeront en progreſſion arithmetique, puiſ-<lb/> <anchor type="note" xlink:label="note-0292-03a" xlink:href="note-0292-03"/> qu’ils compoſent enſemble les élemens d’un triangle: </s> <s xml:id="echoid-s6460" xml:space="preserve">d’un autre <lb/>côté, nous avons deux leviers recourbés CAG, & </s> <s xml:id="echoid-s6461" xml:space="preserve">BAE, qui ont <lb/>le même point d’apui K; </s> <s xml:id="echoid-s6462" xml:space="preserve">& </s> <s xml:id="echoid-s6463" xml:space="preserve">s’il y a une puiſſance apliquée à cha-<lb/>que extrêmité des bras AE, & </s> <s xml:id="echoid-s6464" xml:space="preserve">AG, comme nous l’avons ſupoſé, <lb/>on pourra dire alors que les bras AB, & </s> <s xml:id="echoid-s6465" xml:space="preserve">AC, répondent au fibre, <lb/>ou premier lien BC, de même que les bras HA, & </s> <s xml:id="echoid-s6466" xml:space="preserve">IA, répon- <pb o="9" file="0293" n="304" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> dent au fibre HI, & </s> <s xml:id="echoid-s6467" xml:space="preserve">ainſi de tous les autres qui auront des bras de <lb/>leviers, plus ou moins grands, ſelon qu’ils ſeront éloignés du point <lb/>d’apui; </s> <s xml:id="echoid-s6468" xml:space="preserve">d’où il s’enſuit que les bras de leviers ſont en progreſſion <lb/>arithmetique, de même que les fibres qui leur répondent, & </s> <s xml:id="echoid-s6469" xml:space="preserve">que <lb/>les progreſſions de part & </s> <s xml:id="echoid-s6470" xml:space="preserve">d’autre vont ſe terminer à zero au point <lb/>A; </s> <s xml:id="echoid-s6471" xml:space="preserve">l’on peut donc dire à cauſe des triangles ſemblables, que le <lb/>produit du bras de levier AB, par le fibre BC, ſera celui du bras <lb/>de levier AH, par le fibre HI, comme le quarré de AB, eſt au <lb/>quarré de AH, & </s> <s xml:id="echoid-s6472" xml:space="preserve">que par conſequent l’effort de tous les fibres, <lb/>relativement à leurs bras de leviers, diminuent en venant vers le <lb/>point d’apui, dans la raiſon des quarrés, des termes d’une progreſ-<lb/>ſion arithmetique; </s> <s xml:id="echoid-s6473" xml:space="preserve">ainſi l’effort de tous les fibres étant répandu <lb/>dans le triangle ABC, ne ſera que le tiers de ce qu’il ſeroit, s’il <lb/>étoit réuni aux extrêmités B, & </s> <s xml:id="echoid-s6474" xml:space="preserve">C, des bras de leviers AB, & </s> <s xml:id="echoid-s6475" xml:space="preserve">AC; <lb/></s> <s xml:id="echoid-s6476" xml:space="preserve">puiſque la ſomme de tous les quarrés de la progreſſion ne vaut <lb/> <anchor type="note" xlink:label="note-0293-01a" xlink:href="note-0293-01"/> que le tiers du produit du plus grand quarré, par la grandeur qui <lb/>exprime la quantité des mêmes quarrés; </s> <s xml:id="echoid-s6477" xml:space="preserve">c’eſt pourquoi dans la ſui-<lb/>te on pourra ſans difficulté ſupoſer que la force de tous les fi-<lb/>bres eſt réunie à l’extrêmité du bras de levier, qui répond à la <lb/>puiſſance reſiſtante, quand au lieu d’admettre cette puiſſance telle <lb/>qu’elle eſt effectivement, on n’en ſupoſera que le tiers.</s> <s xml:id="echoid-s6478" xml:space="preserve"/> </p> <div xml:id="echoid-div305" type="float" level="3" n="1"> <note position="left" xlink:label="note-0292-01" xlink:href="note-0292-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>12.</note> <note position="left" xlink:label="note-0292-02" xlink:href="note-0292-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 1.</note> <note position="left" xlink:label="note-0292-03" xlink:href="note-0292-03a" xml:space="preserve">Voyez le <lb/>Cours de <lb/>Mathéma-<lb/>tiq. art. <lb/>240.</note> <note position="right" xlink:label="note-0293-01" xlink:href="note-0293-01a" xml:space="preserve">V. le C. <lb/>Art. 366.</note> </div> <p> <s xml:id="echoid-s6479" xml:space="preserve">Preſentement, pour juger de la force du bois, commençons par <lb/> <anchor type="note" xlink:label="note-0293-02a" xlink:href="note-0293-02"/> examiner ce qui lui arrive quand il vient à ſe rompre; </s> <s xml:id="echoid-s6480" xml:space="preserve">ainſi ima-<lb/>ginons que l’on a poſé une poutre ou ſolive AC, ſur deux apuis, <lb/>il eſt conſtant que ſi on la charge dans ſon milieu d’un poids con-<lb/>ſiderable, la face ſuperieure ſortira de l’allignement horiſontal, <lb/>pour former un angle qui ſera d’abord un peu curviligne, & </s> <s xml:id="echoid-s6481" xml:space="preserve">qui <lb/>deviendra toûjours plus ſenſible, à meſure que le poids exercera <lb/>davantage ſa peſanteur, juſqu’à ce que les deux moitiés BA, & </s> <s xml:id="echoid-s6482" xml:space="preserve"><lb/>BC, ſe ſépareront dans le moment que la ſolive ſe rompra. </s> <s xml:id="echoid-s6483" xml:space="preserve">Or re-<lb/>marqués qu’au commencement les fibres qui ſont le long de la <lb/>ligne EF, dans la face ſuperieure, paroîtront ſe ſerrer, pendant <lb/>que ceux qui ſont opoſés dans la face inferieure s’alongeront & </s> <s xml:id="echoid-s6484" xml:space="preserve"><lb/>commenceront à ſe ſeparer: </s> <s xml:id="echoid-s6485" xml:space="preserve">ainſi, quand la force qui les uniſſoit <lb/>devient inferieure à la puiſſance qui agit, ils rompent tous preſque <lb/>dans le même inſtant, mais avant cela ils ſe ſont trouvés d’autant <lb/>plus tendus les uns que les autres, qu’ils étoient plus éloignés de <lb/>la ligne EF, que l’on peut regarder comme le point d’apui, com-<lb/>mun aux deux leviers recourbés HEA, & </s> <s xml:id="echoid-s6486" xml:space="preserve">GEC, car tout ce que <lb/>nous avons vû ci-devant ſe retrouve dans la deuxiéme figure; </s> <s xml:id="echoid-s6487" xml:space="preserve">la <lb/>difference eſt ſeulement, que la ſolive ayant une épaiſſeur déter- <pb o="10" file="0294" n="305" rhead="LA SCIENCE DES INGENIEURS,"/> minée EF, tous les fibres, que le poids aura à vaincre, ſeront ex-<lb/>primés enſemble par la ſuperficie du plan GEFI, où ſi l’on veut <lb/>par la baſe de la poutre, & </s> <s xml:id="echoid-s6488" xml:space="preserve">alors tous ces fibres pourront être re-<lb/>gardés comme une quantité de plans extrêmement minces, poſés <lb/>les uns ſur les autres, dont la largeur eſt toûjours égale à EF; </s> <s xml:id="echoid-s6489" xml:space="preserve">& </s> <s xml:id="echoid-s6490" xml:space="preserve"><lb/>comme la reſiſtance de chacun dépend encore de l’éloignement <lb/>où il ſera du point d’apui, par raport au bras de levier qui lui ré-<lb/>pond; </s> <s xml:id="echoid-s6491" xml:space="preserve">il s’enſuit que pour reduire tous ces plans ou fibres à n’a-<lb/>voir qu’un bras de levier commun, il faudra que ce bras de levier <lb/>ne ſoit que le tiers de la ligne EG, ou bien ſi l’on veut les réunir <lb/>le long de la ligne GI, ou ſeulement au point G, extrêmité du <lb/>bras de levier EG, il faudra ne prendre que le tiers du plan GBFI; <lb/></s> <s xml:id="echoid-s6492" xml:space="preserve">on peut donc dire que la reſiſtance de cette ſolive peut être expri-<lb/>mée par le produit de la ligne EG, & </s> <s xml:id="echoid-s6493" xml:space="preserve">du tiers de la baſe GEFI.</s> <s xml:id="echoid-s6494" xml:space="preserve"/> </p> <div xml:id="echoid-div306" type="float" level="3" n="2"> <note position="right" xlink:label="note-0293-02" xlink:href="note-0293-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 2.</note> </div> <p> <s xml:id="echoid-s6495" xml:space="preserve">Pour raporter cette theorie à quelque notion connuë, remar-<lb/>qués que plus une piece de bois a de longueur, plus la puiſſance <lb/>a de facilité à la rompre; </s> <s xml:id="echoid-s6496" xml:space="preserve">la raiſon eſt ſans doute qu’ayant un plus <lb/>grand bras de levier, cette puiſſance doit avoir neceſſairement plus <lb/>d’avantage, ſi on n’a rien changé aux dimenſions de la baſe, car ſi <lb/>le plan CEFI demeure le même, la reſiſtance ou la force de la <lb/>ſolive ſera toûjours exprimée par le même produit, au lieu que ſi <lb/>on double la longueur de la ſolive, il ne faudra à la puiſſance que <lb/>la moitié de la force dont elle avoit beſoin auparavant pour la <lb/>rompre.</s> <s xml:id="echoid-s6497" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6498" xml:space="preserve">Si ſans toucher à la longueur de la ſolive, ni à l’épaiſſeur hori-<lb/>ſontale GI, on doubloit la hauteur EG, ſa reſiſtance ſeroit qua-<lb/>druple de ce qu’elle étoit auparavant, puiſque le bras de levier <lb/>EG, ſe trouveroit doublé auſſi bien que le nombre de fibres, c’eſt-<lb/>à-dire, le plan GEFI; </s> <s xml:id="echoid-s6499" xml:space="preserve">d’où il s’enſuit, que de deux ſolives ou deux <lb/>poutres d’un même bois, d’égale longueur & </s> <s xml:id="echoid-s6500" xml:space="preserve">épaiſſeur, la pre-<lb/>miere aura quatre fois plus de force que la ſeconde, ſi la hauteur <lb/>verticale de la premiere eſt double de celle de la ſeconde, & </s> <s xml:id="echoid-s6501" xml:space="preserve">qu’en <lb/>genéral la reſiſtance des poutres d’une même longueur, ſont dans <lb/>la raiſon des produits du tiers de leur baſe par leur hauteur vertica-<lb/>le: </s> <s xml:id="echoid-s6502" xml:space="preserve">mais comme ces deux produits auront toûjours le même ra-<lb/>port, ſoit qu’on les laiſſe tels qu’ils ſont, ou qu’on les multiplie <lb/>l’un & </s> <s xml:id="echoid-s6503" xml:space="preserve">l’autre par trois, il eſt bien plus commode de dire, qu’ayant <lb/> <anchor type="note" xlink:label="note-0294-01a" xlink:href="note-0294-01"/> deux poutres de même longueur AB, & </s> <s xml:id="echoid-s6504" xml:space="preserve">EF, leur reſiſtance ſera <lb/>dans la raiſon du produit de leurs plans CD, & </s> <s xml:id="echoid-s6505" xml:space="preserve">GH, par leur <lb/>épaiſſeur verticale CB, & </s> <s xml:id="echoid-s6506" xml:space="preserve">GF, ou ce qui vaut mieux encore, com-<lb/>me le produit du quarré de la hauteur verticale CB, de l’une multipliée par <pb o="11" file="0295" n="306" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> ſon épaiſſeur BD, eſt au produit du quarré de la hauteur verticale GF, de <lb/>l’autre par ſon epaiſſeur horiſontale FH. </s> <s xml:id="echoid-s6507" xml:space="preserve">Il faut s’attacher à bien enten-<lb/>dre cette derniere maniere, de conſiderer le raport de la reſiſtan-<lb/>ce des poutres ou ſolives, parce que c’eſt la ſeule dont nous fe-<lb/>rons mention par la ſuite, comme la plus ſimple & </s> <s xml:id="echoid-s6508" xml:space="preserve">la plus claire.</s> <s xml:id="echoid-s6509" xml:space="preserve"/> </p> <div xml:id="echoid-div307" type="float" level="3" n="3"> <note position="left" xlink:label="note-0294-01" xlink:href="note-0294-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 3. <lb/>& 4.</note> </div> <p> <s xml:id="echoid-s6510" xml:space="preserve">Mais, ſi on avoit deux poutres comme IK, & </s> <s xml:id="echoid-s6511" xml:space="preserve">NO, dont les lon-<lb/> <anchor type="note" xlink:label="note-0295-01a" xlink:href="note-0295-01"/> gueurs fuſſent inégales, auſſi bien que les dimenſions de leurs baſes, <lb/>& </s> <s xml:id="echoid-s6512" xml:space="preserve">qu’on voulut ſavoir la force de ces poutres poſées ſur les côtés <lb/>LM, & </s> <s xml:id="echoid-s6513" xml:space="preserve">PQ, il faut multiplier le quarré de la hauteur KL, de la <lb/>premiere, par la largeur LM, de ſa baſe, & </s> <s xml:id="echoid-s6514" xml:space="preserve">diviſer le produit par <lb/>la longueur IK; </s> <s xml:id="echoid-s6515" xml:space="preserve">de même on multipliera le quarré de la hauteur <lb/>verticale OP, de la ſeconde poutre, par l’épaiſſeur PQ, de ſa baſe, <lb/>& </s> <s xml:id="echoid-s6516" xml:space="preserve">l’on diviſera le produit par la longueur NO; </s> <s xml:id="echoid-s6517" xml:space="preserve">ſi l’on compare en-<lb/>ſuite ces deux quotiens, leur raport ſera égal à celui de la force <lb/>ou de la reſiſtance des deux poutres, de ſorte que ſi par exemple <lb/>la hauteur KL, étoit de 12. </s> <s xml:id="echoid-s6518" xml:space="preserve">pouces, la largeur LM, de 8. </s> <s xml:id="echoid-s6519" xml:space="preserve">& </s> <s xml:id="echoid-s6520" xml:space="preserve">la <lb/>longueur IK, de 36. </s> <s xml:id="echoid-s6521" xml:space="preserve">pieds, multipliant le quarré de 12. </s> <s xml:id="echoid-s6522" xml:space="preserve">qui eſt 144. <lb/></s> <s xml:id="echoid-s6523" xml:space="preserve">par 8. </s> <s xml:id="echoid-s6524" xml:space="preserve">le produit ſera 1152. </s> <s xml:id="echoid-s6525" xml:space="preserve">qui étant diviſé par 36. </s> <s xml:id="echoid-s6526" xml:space="preserve">il vient 32. </s> <s xml:id="echoid-s6527" xml:space="preserve">de <lb/>même ſupoſant OP, de 14. </s> <s xml:id="echoid-s6528" xml:space="preserve">pouces, PQ, de 10. </s> <s xml:id="echoid-s6529" xml:space="preserve">& </s> <s xml:id="echoid-s6530" xml:space="preserve">la longueur NO, <lb/>de 24. </s> <s xml:id="echoid-s6531" xml:space="preserve">pieds, le quarré de OP, ſera de 196. </s> <s xml:id="echoid-s6532" xml:space="preserve">& </s> <s xml:id="echoid-s6533" xml:space="preserve">ſon produit par PQ, <lb/>1960. </s> <s xml:id="echoid-s6534" xml:space="preserve">qui étant diviſé par 24. </s> <s xml:id="echoid-s6535" xml:space="preserve">donne 81. </s> <s xml:id="echoid-s6536" xml:space="preserve">deuxtiers; </s> <s xml:id="echoid-s6537" xml:space="preserve">ainſila force de la <lb/>poutre IK, ſera à celle de la poutre NO, comme 32. </s> <s xml:id="echoid-s6538" xml:space="preserve">eſt à 81. </s> <s xml:id="echoid-s6539" xml:space="preserve">deux <lb/>tiers; </s> <s xml:id="echoid-s6540" xml:space="preserve">la raiſon de cette regle ſe fait aſſés ſentir, ſans qu’il ſoit beſoin que <lb/>je l’explique, puiſqu’il ſaute aux yeux, que plus une poutre eſt lon-<lb/>gue, moins elle a de force; </s> <s xml:id="echoid-s6541" xml:space="preserve">& </s> <s xml:id="echoid-s6542" xml:space="preserve">que par conſequent ſi l’on prend la <lb/>longueur pour diviſer la quantité qui exprime ſa réſiſtance, c’eſt-à-<lb/>dire le produit du quarré de ſa hauteur, par la longueur de ſa baſe, <lb/>le quotien ſera d’autant plus petit que le diviſeur ſera grand.</s> <s xml:id="echoid-s6543" xml:space="preserve"/> </p> <div xml:id="echoid-div308" type="float" level="3" n="4"> <note position="right" xlink:label="note-0295-01" xlink:href="note-0295-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 5. <lb/>& 6.</note> </div> <p> <s xml:id="echoid-s6544" xml:space="preserve">Etant prévenu que l’épaiſſeur verticale d’une poutre exprime le <lb/>bras de levier qui répond à la puiſſance reſiſtante, l’on voit que <lb/>plus cette hauteur ſera grande, plus la poutre aura de force, & </s> <s xml:id="echoid-s6545" xml:space="preserve">par <lb/>conſequent une même poutre poſée de cant, je veux dire ſur le <lb/>plus petit côté de ſa baſe, reſiſtera d’avantage que poſé ſur le <lb/>plat, dans la raiſon que la premiere ſituation lui donnera une plus <lb/>grande hauteur que la ſeconde; </s> <s xml:id="echoid-s6546" xml:space="preserve">par exemple, une poutre qui au-<lb/>roit 8. </s> <s xml:id="echoid-s6547" xml:space="preserve">pieds ſur 16. </s> <s xml:id="echoid-s6548" xml:space="preserve">aura deux fois plus de force poſée de cant, <lb/>que ſi elle étoit poſée de plat, ainſi deux poutres d’une longueur <lb/>égale, & </s> <s xml:id="echoid-s6549" xml:space="preserve">dont les baſes ſeroient auſſi égales, peuvent avoir des re-<lb/>ſiſtances differentes à l’infini, puiſque ſi l’on ſupoſe la hauteur de <lb/>la baſe de l’une infiniment grande, & </s> <s xml:id="echoid-s6550" xml:space="preserve">ſa largeur infiniment petite, <lb/>tandis que les dimenſions de la baſe de l’autre poutre demeure- <pb o="12" file="0296" n="307" rhead="LA SCIENCE DES INGENIEURS,"/> roient les mêmes; </s> <s xml:id="echoid-s6551" xml:space="preserve">la reſiſtance de la premiere poſée de cant ſe-<lb/>roit infiniment plus grande que celle de la ſeconde, quoique leur <lb/>ſolidité ou leur maſſe füt égale: </s> <s xml:id="echoid-s6552" xml:space="preserve">mais comme ces ſortes de ſupo-<lb/>ſitions ne peuvent avoir lieu dans la pratique, parce qu’il faut pour <lb/>la liaiſon d’un bâtiment, que les poutres ayent une certaine aſſié-<lb/>te, & </s> <s xml:id="echoid-s6553" xml:space="preserve">une hauteur renfermée dans un juſte milieu, il ſuffit de ſa-<lb/>voir, qu’après avoir donné à une poutre une aſſiéte convenable, on <lb/>ne ſauroit lui donner trop d’épaiſſeur verticale pour la rendre ca-<lb/>pable de porter de grands fardeaux.</s> <s xml:id="echoid-s6554" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6555" xml:space="preserve">Dans ce que nous venons de dire, on a ſupoſé que les poutres <lb/>avoient des baſes rectangulaires; </s> <s xml:id="echoid-s6556" xml:space="preserve">mais ſi ces baſes étoient circu-<lb/>laires, les mêmes choſes n’en ſubſiſteroient pas moins, les diamêtres <lb/>des cercles repreſenteront toûjours les bras de leviers, qui répon-<lb/>dent aux puiſſances reſiſtantes, & </s> <s xml:id="echoid-s6557" xml:space="preserve">leur ſuperficie le plan des fibres <lb/>que les puiſſances agiſſantes auront à vaincre.</s> <s xml:id="echoid-s6558" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6559" xml:space="preserve">Les Entrepreneurs & </s> <s xml:id="echoid-s6560" xml:space="preserve">les Marchands de Bois, étant payés au cent <lb/>de ſolives, font enſorte d’en multiplier le nombre le plus qu’il leur <lb/>eſt poſſible; </s> <s xml:id="echoid-s6561" xml:space="preserve">c’eſt pourquoi ils débitent les poutres & </s> <s xml:id="echoid-s6562" xml:space="preserve">les autres groſ-<lb/>ſes piéces quarrément, parce que le quarré eſt le plus grand de tous <lb/>les rectangles qu’on peut inſcrire dans le cercle d’un arbre. </s> <s xml:id="echoid-s6563" xml:space="preserve">cepen-<lb/>dant, ſelon ce qu’on vient de voir, une poutre qui auroit 10 ſur 14 <lb/>eſt préferable à une autre d’une même longueur qui auroit 12 ſur 12, <lb/>la premiere contenant moins de ſolives que la ſeconde, & </s> <s xml:id="echoid-s6564" xml:space="preserve">en mê-<lb/>me tems plus forte, le raport de leur prix étant comme 140 à 144, <lb/>tandis que celui de leur force eſt comme 245 à 216, qui ſont deux <lb/>avantages conſidérables: </s> <s xml:id="echoid-s6565" xml:space="preserve">& </s> <s xml:id="echoid-s6566" xml:space="preserve">l’Experience, qui prévient aſſés ſouvent <lb/>la Théorie, a fait apercevoir depuis long-tems, que les dimenſions <lb/>qu’il convenoit mieux de donner à la baſe d’une poutre, devoient <lb/>être dans le raport de 5 à 7, ou ce qui revient à peu-près au même, <lb/>faire enſorte que le quarré de la hauteur verticale ſoit double du <lb/>quarré de l’épaiſſeur horiſontale, puiſque le quarré de 7 qui eſt 49 <lb/>eſt à une unité près, double du quarré de 5 qui eſt 25. </s> <s xml:id="echoid-s6567" xml:space="preserve">Auſſi Mr. </s> <s xml:id="echoid-s6568" xml:space="preserve">Parent <lb/>a démontré que la baſe de la plus forte poutre, qu’on pouvoit tirer <lb/>du cercle d’un arbre, étoit effectivement celle dont le quarré du <lb/>plus grand côté ſeroit double du quarré du plus petit; </s> <s xml:id="echoid-s6569" xml:space="preserve">&</s> <s xml:id="echoid-s6570" xml:space="preserve">, en ſuivant <lb/>ſon principe, voici une maniere bien aiſée de tracer dans le cercle <lb/>d’un arbre la baſe qu’il faut donner à la plus ſorte poutre qu’on peut <lb/>tirer du même arbre.</s> <s xml:id="echoid-s6571" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6572" xml:space="preserve">Il faut diviſer le diamêtre AB, de l’arbre en trois parties égales <lb/> <anchor type="note" xlink:label="note-0296-01a" xlink:href="note-0296-01"/> aux points C & </s> <s xml:id="echoid-s6573" xml:space="preserve">D, abaiſſer la perpendiculaire DE, au-deſſous du <lb/>diamêtre; </s> <s xml:id="echoid-s6574" xml:space="preserve">& </s> <s xml:id="echoid-s6575" xml:space="preserve">élever la perpendiculaire CF au-deſſus, & </s> <s xml:id="echoid-s6576" xml:space="preserve">tracer le rec- <pb o="13" file="0297" n="308" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> tangle AEBF, qui ſera celui que l’on demande, puiſqu’il eſt aifé de <lb/>prouver que le quarré du côté FB eſt double du quarré de l’autre <lb/>côté FA, comme on le va voir.</s> <s xml:id="echoid-s6577" xml:space="preserve"/> </p> <div xml:id="echoid-div309" type="float" level="3" n="5"> <note position="left" xlink:label="note-0296-01" xlink:href="note-0296-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 9.</note> </div> <p> <s xml:id="echoid-s6578" xml:space="preserve">Si l’on nomme a, chaque partie égale du diamêtre, CB ſera 2a; <lb/></s> <s xml:id="echoid-s6579" xml:space="preserve">& </s> <s xml:id="echoid-s6580" xml:space="preserve">comme le rectangle de AC, par CB, eſt égal au quarré de CF, <lb/>ce quarré vaudra donc 2aa, par conſéquent l’on aura <emph style="ol">AC</emph><emph style="sub">2</emph> + <emph style="ol">CF</emph><emph style="sub">2</emph>, <lb/>(aa + 2aa) = <emph style="ol">AF</emph><emph style="sub">2</emph> (3aa) de même l’on aura encore <emph style="ol">CB</emph><emph style="sub">2</emph> + <emph style="ol">CF</emph><emph style="sub">2</emph>, <lb/>(4aa + 2aa) = <emph style="ol">FB</emph><emph style="sub">2</emph> (6aa) qui montre que le quarré FB, eſt double <lb/>du quarré de FA. </s> <s xml:id="echoid-s6581" xml:space="preserve">Les poutres étant les piéces plus eſſentielles de la <lb/>charpente, je m’y arrêterai préférablement aux autres, & </s> <s xml:id="echoid-s6582" xml:space="preserve">comme il <lb/>arrive preſque toûjours que leurs extrêmités ſont engagées dans l’é-<lb/>paiſſeur des murs, & </s> <s xml:id="echoid-s6583" xml:space="preserve">non pas ſimplement poſées ſur des apuis, com-<lb/>me on l’a vû ci-devant, il eſt neceſſaire de s’attacher à ce qui eſt <lb/>le plus d’uſage, & </s> <s xml:id="echoid-s6584" xml:space="preserve">par conſequent à ce qui peut arriver aux poutres <lb/>lorſqu’étant employées dans des bâtimens, on les charge de quelque <lb/>poids conſiderable; </s> <s xml:id="echoid-s6585" xml:space="preserve">mais afin de rendre ce que j’ai à dire plus intel-<lb/>ligible, je commencerai à conſidérer une ſolive ou une poutre poſée <lb/> <anchor type="note" xlink:label="note-0297-01a" xlink:href="note-0297-01"/> horiſontalement de façon qu’une de ſes extrêmités ſoit engagée dans <lb/>un mur & </s> <s xml:id="echoid-s6586" xml:space="preserve">que l’autre porte à faux, c’eſt-à-dire, reſte en l’air ſans <lb/>être ſoutenuë, ainſi voyés la muraille AB, dont l’épaiſſeur ſera par <lb/>exemple de deux pieds & </s> <s xml:id="echoid-s6587" xml:space="preserve">demi, on ſupoſe que l’extrêmité d’une <lb/>poutre eſt engagée dans cette muraille & </s> <s xml:id="echoid-s6588" xml:space="preserve">bien ſerrée de tout côté, <lb/>enſorte que la partie EK qui eſt en dehors ſe ſoûtiendroit d’elle même <lb/>horiſontalement ſi aucune force étrangeren’y touchoit, (parce que <lb/>l’on fait abſtraction de ſon propre poids.) </s> <s xml:id="echoid-s6589" xml:space="preserve">Cependant ſi à l’extrê-<lb/>mité K on ſuſpendoit un poids M aſſés conſiderable pour faire plier <lb/>la poutre, d’abord elle commencera à ſe courber & </s> <s xml:id="echoid-s6590" xml:space="preserve">fera effort à <lb/>l’autre extrêmité pour ſortir du mur; </s> <s xml:id="echoid-s6591" xml:space="preserve">mais comme elle y eſt ſi bien <lb/>arrêtée que le bout enfermé ne peut abſolument bouger, toute la <lb/>violence que l’on fera à cette poutre ſe terminera à l’endroit DCHF, <lb/>de la ſurface, les fibres qui touchent la ligne HC, s’allongeront à <lb/>meſure que l’on augmentera la péſanteur du poids M, & </s> <s xml:id="echoid-s6592" xml:space="preserve">il y aura <lb/>un inſtant où ceux qui ſont hors du mur, ſe dêtacheront d’avec <lb/>ceux qui ſont dedans, & </s> <s xml:id="echoid-s6593" xml:space="preserve">alors l’équilibre étant rompu, le poids M, <lb/>emportera la poutre, & </s> <s xml:id="echoid-s6594" xml:space="preserve">pendant que cet effort ſe fera, la ligne FD, <lb/>qui repreſente le bord du trou de la muraille ſoûtiendra toute l’ac-<lb/>tion du poids & </s> <s xml:id="echoid-s6595" xml:space="preserve">ſera par conſequent le point d’apui lequel répond <lb/>à un lévier recourbé EDL qui ſera ſi l’on veut formé par deux plans <lb/>GEDF & </s> <s xml:id="echoid-s6596" xml:space="preserve">FDLN. </s> <s xml:id="echoid-s6597" xml:space="preserve">Or comme le plan DEGF, comprend tous les <pb o="14" file="0298" n="309" rhead="LA SCIENCE DES INGENIEURS,"/> fibres qui doivent être rompus, ſi l’on ſupoſe comme ci-devant que <lb/>leur réſiſtance ſoit réünie le long de la ligne EG & </s> <s xml:id="echoid-s6598" xml:space="preserve">même au point <lb/>E, l’on pourra concevoir que la puiſſance réſiſtante, c’eſt-à-dire <lb/>la force du bois eſt apliquée à l’extrêmité du bras DE du lévier <lb/>EDL, tandis que la puiſſance agiſſante eſt à l’autre extrêmité L, du <lb/>bras DL, & </s> <s xml:id="echoid-s6599" xml:space="preserve">que par conſequent ceci retombe dans tout ce que <lb/>nous avons dit au ſujet d’une poutre qui ayant ſes extrêmités poſées <lb/>ſur deux apuis, tend à être rompuë dans le milieu par l’action d’un <lb/>poids qui ſeroit poſé deſſus ou ſuſpendu.</s> <s xml:id="echoid-s6600" xml:space="preserve"/> </p> <div xml:id="echoid-div310" type="float" level="3" n="6"> <note position="right" xlink:label="note-0297-01" xlink:href="note-0297-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 11.</note> </div> <p> <s xml:id="echoid-s6601" xml:space="preserve">Si l’on imagine preſentement une poutre engagée par ſes extrê-<lb/> <anchor type="note" xlink:label="note-0298-01a" xlink:href="note-0298-01"/> mités, dans deux murs AB & </s> <s xml:id="echoid-s6602" xml:space="preserve">CD, qu’on ſupoſe paralelles, je dis <lb/>que ſi l’on charge le milieu de cette poutre d’un poids conſidera-<lb/>ble, elle ſe caſſera en trois endroits, dans le milieu & </s> <s xml:id="echoid-s6603" xml:space="preserve">aux deux ex-<lb/>trêmités, ce qui ne peut arriver autrement, ſi l’on fait attention que <lb/>quand la poutre commence à faire un angle dans le milieu, elle ne <lb/>peut quitter la ligne horiſontale EF, ſans que chaque extrêmité ne <lb/>faſſe effort pour ſe rompre; </s> <s xml:id="echoid-s6604" xml:space="preserve">car tout ce que nous avons aperçû dans <lb/>la 2<emph style="sub">e</emph> & </s> <s xml:id="echoid-s6605" xml:space="preserve">la 11<emph style="sub">e</emph> Figure, ſe trouve réüni ici, puiſque pour la rup-<lb/>ture qui doit ſe faire dans le milieu, nous avons les deux léviers re-<lb/>courbés IGM & </s> <s xml:id="echoid-s6606" xml:space="preserve">HGP, & </s> <s xml:id="echoid-s6607" xml:space="preserve">pour celle des extrêmités l’on a auſſi les <lb/>deux autres léviers PQH & </s> <s xml:id="echoid-s6608" xml:space="preserve">MNI, par conſequent le poids qui ſeroit <lb/>dans le milieu exercera l’action de ſa péſanteur en trois endroits à <lb/>la fois; </s> <s xml:id="echoid-s6609" xml:space="preserve">puiſque d’abord les fibres qui uniſſoient les points H & </s> <s xml:id="echoid-s6610" xml:space="preserve">I, <lb/>étoient tendus auſſi fort que ceux qui uniſſoient d’une part les points <lb/>M & </s> <s xml:id="echoid-s6611" xml:space="preserve">F, & </s> <s xml:id="echoid-s6612" xml:space="preserve">de l’autre les points E & </s> <s xml:id="echoid-s6613" xml:space="preserve">P; </s> <s xml:id="echoid-s6614" xml:space="preserve">ainſi quand ceux du milieu <lb/>commencent à ſe rompre, il s’en détache à chaque extrêmité un <lb/>même nombre & </s> <s xml:id="echoid-s6615" xml:space="preserve">dans le mème tems. </s> <s xml:id="echoid-s6616" xml:space="preserve">On peut donc conclure <lb/>qu’une poutre dontles extrêmités ſont bien engagées & </s> <s xml:id="echoid-s6617" xml:space="preserve">ſerrées dans <lb/>des murs, étant chargée d’un poids conſiderable dans ſon milieu, <lb/>ce poids excerce un tiers de ſa péſanteur à chaque endroit qui tend <lb/>à ſe caſſer, & </s> <s xml:id="echoid-s6618" xml:space="preserve">que par conſequent on ne ſauroit trop prendre de <lb/>précautions dans la Conſtruction des bâtimens pour bien engager <lb/>& </s> <s xml:id="echoid-s6619" xml:space="preserve">ſerrer les extrêmités des poutres, parce qu’elle en ſont beaucoup <lb/>plus fortes & </s> <s xml:id="echoid-s6620" xml:space="preserve">qu’on prévient par-là les accidens qui arrivent ſouvent <lb/>faute de bien connoître la conſequence des ſuites dans leſquelles <lb/>on ne manque pas de tomber quand on travaille ſans raiſonner.</s> <s xml:id="echoid-s6621" xml:space="preserve"/> </p> <div xml:id="echoid-div311" type="float" level="3" n="7"> <note position="left" xlink:label="note-0298-01" xlink:href="note-0298-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <p> <s xml:id="echoid-s6622" xml:space="preserve">L’on dira peut-être qu’on a peine à s’imaginer qu’une poutre qui <lb/>eſt retenuë par les deux bouts, comme elles le ſont ordinairement, <lb/>puiſſe ſe rompre à l’endroit des apuis, puiſque cela eſt contraire à <lb/>l’experience qui montre que cette rupture ſe fait toûjours dans le <lb/>milieu. </s> <s xml:id="echoid-s6623" xml:space="preserve">Il eſt vrai que cela arrive ſouvent; </s> <s xml:id="echoid-s6624" xml:space="preserve">mais, c’eſt par une cauſe <pb o="15" file="0299" n="310" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> qui n’a rien de commun avec ce que l’on vient d’inſinuer, puiſque <lb/>ſi l’on y fait attention, l’on verra que quand les poutres ſe courbent <lb/>dans le milieu, ou ſont prêtes à ſe rompre, leurs extrêmités ſont ſor-<lb/>ties de leur ſituation naturelle, c’eſt-à-dire qu’elles ont un peu cha-<lb/>riées, ce qui provient d’ordinaire de ce que la maçonnerie qui eſt <lb/>au-deſſus s’eſt degradée, ne ſerre pas la poutre, & </s> <s xml:id="echoid-s6625" xml:space="preserve">leur laiſſe aſſés de <lb/>jeu pour n’être pas contre-peſée par le poids qui la maintenoit fixe, <lb/>ou bien on employe des poutres trop courtes qui n’étant engagées <lb/>dans le mur que de 5 ou 6 pouces, il n’y en a point une aſſés grande <lb/>partie d’embraſſée pour qu’elle pût être ſerrée comme il faut; </s> <s xml:id="echoid-s6626" xml:space="preserve">& </s> <s xml:id="echoid-s6627" xml:space="preserve">c’eſt <lb/>en quelque maniere pour ce ſujet qu’on les retient toûjours par des <lb/>ancres, mais qui ſont foibles ou mal acrochées & </s> <s xml:id="echoid-s6628" xml:space="preserve">qui ne peuvent <lb/>jamais faire le même effet que ſi la poutre repoſoit ſur toute l’épaiſ-<lb/>ſeur du mur, parce que ces ancres ſe plient & </s> <s xml:id="echoid-s6629" xml:space="preserve">ſuivent la poutre dans <lb/>la ſituation qu’elle eſt contrainte de prendre.</s> <s xml:id="echoid-s6630" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6631" xml:space="preserve">Les principes que je viens d’établir, quoique très-évidens, ſeront <lb/>ſans doute reçûs encore avec plus de conſiance, ſi je montre que <lb/>les Experiences, que j’ai faites ſur la force du bois, ſont parfaitement <lb/>d’accord avec nôtre théorie; </s> <s xml:id="echoid-s6632" xml:space="preserve">& </s> <s xml:id="echoid-s6633" xml:space="preserve">ce qui m’a le plus ſatisfait dans ces <lb/>Experiences, c’eſt de voir qu’elles ſe rencontroient aſſés bien avec <lb/>celles de Mr. </s> <s xml:id="echoid-s6634" xml:space="preserve">Parent; </s> <s xml:id="echoid-s6635" xml:space="preserve">mais ſur leſquelles je n’ai pas voulu compter <lb/>que je ne viſſe par moi-même ce qui en étoit: </s> <s xml:id="echoid-s6636" xml:space="preserve">or, pour qu’on <lb/>puiſſe en tirer toute l’utilité qu’on a lieu d’en eſperer, on en va <lb/>voir le détail dans le Chapitre ſuivant, qui pourroit être juſtifié <lb/>par 20 ou 25 Officiers d’Artillerie de l’Ecole de la Fere, qui ſe <lb/>ſont rendus à l’Arſenal de la même Place pour ſe convaincre de ce <lb/>qu’ils m’avoient entendu dire ſur la force du bois dans l’Ecole de <lb/>Mathematique.</s> <s xml:id="echoid-s6637" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div313" type="section" level="2" n="104"> <head xml:id="echoid-head249" xml:space="preserve">CHAPITRE TROISIE’ME.</head> <head xml:id="echoid-head250" style="it" xml:space="preserve">Où l’on raporte pluſieurs Experiences faites ſur la force du <lb/>bois, que l’on applique enſuite à l’uſage qu’on en peut <lb/>faire dans la Conſtruction des Edifices.</head> <p> <s xml:id="echoid-s6638" xml:space="preserve">POUR executer les mêmes Experiences de differente maniere, <lb/>j’ai fait faire un nombre de petites Solives bien équarries & </s> <s xml:id="echoid-s6639" xml:space="preserve"><lb/>toutes de bois de chêne paſſablement bon, plus ſec que vert, à peu- <pb o="16" file="0300" n="311" rhead="LA SCIENCE DES INGENIEURS,"/> près de même qualité & </s> <s xml:id="echoid-s6640" xml:space="preserve">coupées de façon que le fil du bois ſe <lb/>trouvât toûjours dans le même ſens par raport à la ſituation où il <lb/>devoit être poſé.</s> <s xml:id="echoid-s6641" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6642" xml:space="preserve">On s’eſt ſervi de deux chevalets pour tenir lieu d’apui, & </s> <s xml:id="echoid-s6643" xml:space="preserve">l’on en a <lb/>percé la tête afin d’y paſſer des valets de fer pour ſerrer les Solives <lb/>par les deux bouts quand on le jugeroit à propos; </s> <s xml:id="echoid-s6644" xml:space="preserve">& </s> <s xml:id="echoid-s6645" xml:space="preserve">comme dans un <lb/>Arſenal tel que celui de la Fere, il y a un grand nombre de poids <lb/>de toute ſorte de peſanteur & </s> <s xml:id="echoid-s6646" xml:space="preserve">des machines pour les élever, j’ai <lb/>été à portée de faire pluſieurs de mes Experiences en aſſés grand <lb/>volume pour pouvoir ſervir de baſe aux conſequences que j’en ti-<lb/>rerai à la fin de ce Chapitre. </s> <s xml:id="echoid-s6647" xml:space="preserve">Comme il eſt difficile de rencontrer <lb/>du bois dont les morceaux quoique tirès d’une même piece ſoient <lb/>aſſés égaux en toutes choſes pour qu’il ne ſe rencontre pas de diffe-<lb/>rence qui rendroit la plûpart des Experiences équivoques ſi on n’y <lb/>prenoit garde, j’ai repeté chaque Experience trois fois avec des <lb/>pieces de mêmes dimenſions, enſuite j’ai ajoûté enſemble les poids <lb/>que chacune à portée, & </s> <s xml:id="echoid-s6648" xml:space="preserve">le tiers de la ſomme m’a donné un nom-<lb/>bre qui peut exprimer la force moyenne, & </s> <s xml:id="echoid-s6649" xml:space="preserve">c’eſt ce nombre que <lb/>l’on trouve à côté de l’accolade chaque Experience.</s> <s xml:id="echoid-s6650" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6651" xml:space="preserve">Il eſt bon que j’avertiſſe, que quand je dirai qu’une Solive a tant <lb/>de longueur, on doit entendre que cette longueur eſt compriſe en-<lb/>tre les deux apuis, puiſqu’il n’eſt pas neceſſaire de faire mention des <lb/>trois ou quatre pouces qu’on a donné de plus à leur bouts pour re-<lb/>poſer ſur les apuis. </s> <s xml:id="echoid-s6652" xml:space="preserve">J’ajoûterai auſſi, qu’on n’a point eû égard à la pé-<lb/>ſanteur des Solives, & </s> <s xml:id="echoid-s6653" xml:space="preserve">que dans l’aplication que nous ferons de ces <lb/>Experiences aux poutres, on fera auſſi abſtraction de leur poids <lb/>pour rendre les calculs moins compoſés.</s> <s xml:id="echoid-s6654" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div314" type="section" level="2" n="105"> <head xml:id="echoid-head251" style="it" xml:space="preserve">Premiere Experience.</head> <p> <s xml:id="echoid-s6655" xml:space="preserve">Une Solive de 18 pouces de longueur & </s> <s xml:id="echoid-s6656" xml:space="preserve">d’un pouce en quarré, <lb/>poſée ſur deux apuis, ſans être ſerrée par ſes extrêmités, a porté</s> </p> <note position="right" xml:space="preserve">dans ſon milieu un moment avant de ſe caſſer. . # 400 # { # liv. <lb/>Une ſeconde ſemblablement poſée. . . # 415 # # 406 <lb/>Une troiſiéme ſemblable en tout aux précedentes # 405 <lb/></note> <p> <s xml:id="echoid-s6657" xml:space="preserve">Cette experience s’accorde aſſés bien avec la douziéme raportée <lb/>par Mr. </s> <s xml:id="echoid-s6658" xml:space="preserve">Parent, dans les Memoires del’Academie Royale des Scien-<lb/>ces de l’année 1707. </s> <s xml:id="echoid-s6659" xml:space="preserve">où il dit qu’une piece de bois de chêne de <lb/>24 pouces de longueur ſur un pouce en quarré a porté 300 liv. <lb/></s> <s xml:id="echoid-s6660" xml:space="preserve">dans ſon milieu un moment avant de ſe rompre; </s> <s xml:id="echoid-s6661" xml:space="preserve">& </s> <s xml:id="echoid-s6662" xml:space="preserve">comme la <lb/>nôtre de 81 pouces avoit pour longueur les trois quarts de celle <pb o="17" file="0301" n="312" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> de Mr. </s> <s xml:id="echoid-s6663" xml:space="preserve">Parent, elle devoit porter 100 liv. </s> <s xml:id="echoid-s6664" xml:space="preserve">de plus, auſſi ne s’eſt-elle <lb/>rompue que par l’action d’un poids d’environ 400 liv.</s> <s xml:id="echoid-s6665" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div315" type="section" level="2" n="106"> <head xml:id="echoid-head252" style="it" xml:space="preserve">Seconde Experience.</head> <p> <s xml:id="echoid-s6666" xml:space="preserve">Une Solive de 18 pouces de longueur ſur un pouce en quarré</s> </p> <note position="right" xml:space="preserve">ſerrée par ſes deux extrêmités a porté avant de ſe rompre. # 600 # } # liv. <lb/>Une ſeconde de même ſerrée par ſes extrêmités. # 600 # # 608 <lb/>Une troiſiéme telle que les précedentes & poſée de \\ même. . . . . . . . # 624 <lb/></note> <p> <s xml:id="echoid-s6667" xml:space="preserve">Comme, dans cette ſeconde Experience, chaque Solive a été ar-<lb/>rêtée par les deux bouts, la queſtion étoit de ſavoir ſi effectivement <lb/>elles romproient en trois endroits, j’ai été ſurpris de voir que la pre-<lb/>miere qui a caſſé avec le poids de 600 liv. </s> <s xml:id="echoid-s6668" xml:space="preserve">n’étoit rompuë que dans <lb/>le milieu, les deux bouts ne s’étant qu’un peu courbés; </s> <s xml:id="echoid-s6669" xml:space="preserve">mais, ayant <lb/>aperçû que les valets qui ſerroient cette Solive avoient tant ſoit peu <lb/>obéï, ne pouvant ſoûtenir un ſi grand poids, j’ai fait retenir celle que <lb/>l’on a miſe en ſecond lieu, par deux valets à chaque extrêmité, au <lb/>lieu d’un; </s> <s xml:id="echoid-s6670" xml:space="preserve">&</s> <s xml:id="echoid-s6671" xml:space="preserve">, après avoir été chargée juſqu’à la peſanteur de 600 <lb/>liv. </s> <s xml:id="echoid-s6672" xml:space="preserve">elle s’eſt rompuë net dans le milieu & </s> <s xml:id="echoid-s6673" xml:space="preserve">aux extrêmités, les deux <lb/>morceaux du milieu étant tombés à terre dans le même tems que le <lb/>poids: </s> <s xml:id="echoid-s6674" xml:space="preserve">la troiſiéme Solive s’eſt auſſi caſſée de même, & </s> <s xml:id="echoid-s6675" xml:space="preserve">pluſieurs <lb/>autres enſuite, qu’on a ſeulement rompu par curioſité.</s> <s xml:id="echoid-s6676" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6677" xml:space="preserve">Cette Experience prouve évidemment, qu’une poutre, arrêtée <lb/>& </s> <s xml:id="echoid-s6678" xml:space="preserve">bien ſerrée par les deux bouts, eſt capable de porter un poids <lb/>beaucoup plus grand que celle qui n’eſt poſée que ſur deux apuis, <lb/>la difference étant comme 3. </s> <s xml:id="echoid-s6679" xml:space="preserve">eſt à 2. </s> <s xml:id="echoid-s6680" xml:space="preserve">c’eſt-à-dire, que la poutre ſerrée <lb/>par les deux bouts eſt plus forte d’un tiers que celle qui ne l’eſt pas.</s> <s xml:id="echoid-s6681" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6682" xml:space="preserve">Ces deux Experiences ſe raportent auſſi à la ſeconde & </s> <s xml:id="echoid-s6683" xml:space="preserve">à la troi-<lb/>ſiéme de Mr. </s> <s xml:id="echoid-s6684" xml:space="preserve">Parent, qui dit qu’ayant une piece de bois de chêne <lb/>longue de 11 pouces ſur 5 à 6 lignes de baſe poſée de cant ſur <lb/>deux apuis ſans êtrc ſerrée par les extrémités a porté 34 liv. </s> <s xml:id="echoid-s6685" xml:space="preserve">& </s> <s xml:id="echoid-s6686" xml:space="preserve">demi <lb/>avant l’inſtant de ſa rupture, & </s> <s xml:id="echoid-s6687" xml:space="preserve">qu’une autre piece toute ſemblable <lb/>à celle-ci, mais ſerrée par les deux bouts, a porté 51 liv. </s> <s xml:id="echoid-s6688" xml:space="preserve">ce qui <lb/>donne auſſi le raport de 3 à 2, dont je viens de parler: </s> <s xml:id="echoid-s6689" xml:space="preserve">la 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s6690" xml:space="preserve">& </s> <s xml:id="echoid-s6691" xml:space="preserve">la <lb/>8<emph style="sub">e</emph>. </s> <s xml:id="echoid-s6692" xml:space="preserve">Experience de cet Auteur prouvent encore la même choſe.</s> <s xml:id="echoid-s6693" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div316" type="section" level="2" n="107"> <head xml:id="echoid-head253" style="it" xml:space="preserve">Troiſiéme Experience.</head> <p> <s xml:id="echoid-s6694" xml:space="preserve">Une Solive de 18 pouces de longueur & </s> <s xml:id="echoid-s6695" xml:space="preserve">de deux pouces ſur <lb/>un pouce d’équarriſſage, poſée à plat ſans être arrêtée par ſes ex-</s> </p> <pb o="18" file="0302" n="313" rhead="LA SCIENCE DES INGENIEURS,"/> <note position="right" xml:space="preserve">trêmités a porté. . . . . . # 810 # } # liv. <lb/>Une ſemblable poſée de même. . . . # 795 # # 805 <lb/>Une troiſiéme poſée encore de même. . # 812 <lb/></note> <p> <s xml:id="echoid-s6696" xml:space="preserve">Ayant vû dans la premiere Experience, qu’une Solive de 18 pou-<lb/>ces de longueur ſur un pouce en quarré poſée ſur deux apuis ſans <lb/>être ſerrée a porté 400 liv. </s> <s xml:id="echoid-s6697" xml:space="preserve">la raiſon veut qu’une autre Solive de <lb/>même longueur & </s> <s xml:id="echoid-s6698" xml:space="preserve">même hauteur poſée auſſi de même, mais qui <lb/>auroit le double en largeur, porte un poids double; </s> <s xml:id="echoid-s6699" xml:space="preserve">auſſi avons-nous <lb/>805 liv. </s> <s xml:id="echoid-s6700" xml:space="preserve">pour la force moyenne au lieu de 800, qui eſt une diffe-<lb/>rence qui ne mérite pas d’attention.</s> <s xml:id="echoid-s6701" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div317" type="section" level="2" n="108"> <head xml:id="echoid-head254" style="it" xml:space="preserve">Quatriéme Experience.</head> <p> <s xml:id="echoid-s6702" xml:space="preserve">Une Solive de même dimenſion que dans la troiſiéme Expe-<lb/>rience, mais poſée de cant ſans être arrêtée par les deux bouts, a</s> </p> <note position="right" xml:space="preserve">porté. . . . . . . # 1570 # } # liv. <lb/>Une ſeconde ſemblable & poſée de même. . # 1580 # # 1580 <lb/>Une troiſieme. . . . . # 1590 <lb/></note> <p> <s xml:id="echoid-s6703" xml:space="preserve">Cette Experience prouve que deux poutres de même longueur, & </s> <s xml:id="echoid-s6704" xml:space="preserve"><lb/>dont la largeur des baſes eſt égale, ont leur force dans la raiſon des <lb/>quarrés de leur hauteur, puiſque la force moyenne d’une Solive qui <lb/>a une hauteur double de celle de la premiere Experience, & </s> <s xml:id="echoid-s6705" xml:space="preserve">dont <lb/>tout le reſte eſt égal, eſt de 1580, qui eſt un nombre à peu près qua-<lb/>druple de 400. </s> <s xml:id="echoid-s6706" xml:space="preserve">Elle montre auſſi que la force d’une poutre poſée <lb/>de plat eſt à celle qu’elle auroit poſée de cant, comme le plus petit <lb/>côté de la baſe eſt au plus grand.</s> <s xml:id="echoid-s6707" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div318" type="section" level="2" n="109"> <head xml:id="echoid-head255" style="it" xml:space="preserve">Cinquiéme Experience.</head> <p> <s xml:id="echoid-s6708" xml:space="preserve">Une Solive de trois pieds de longueur & </s> <s xml:id="echoid-s6709" xml:space="preserve">d’un pouce en quarré,</s> </p> <note position="right" xml:space="preserve">n’étant point ſerrée par ſes deux extrêmités, a porté. # 185 # } # liv. <lb/>Une ſeconde ſemblable & poſée de même. . # 195 # # 187 <lb/>Une troiſiéme. . . . . . # 180 <lb/></note> <p> <s xml:id="echoid-s6710" xml:space="preserve">Cette Experience montre ſenſiblement que de deux poutres qui <lb/>ont leurs baſes égales & </s> <s xml:id="echoid-s6711" xml:space="preserve">poſées ſur le même côté, la plus longue a <lb/>moins de force que la plus courte dans la raiſon qu’elle a plus de <lb/>longueur; </s> <s xml:id="echoid-s6712" xml:space="preserve">car dans la premiere Experience une poutre de 18 <lb/>pouces de longueur, & </s> <s xml:id="echoid-s6713" xml:space="preserve">d’un pouce en quarré, a porté 400 liv. <lb/></s> <s xml:id="echoid-s6714" xml:space="preserve">tandis que la force moyenne d’une autre Solive de 36 pouces de <lb/>longueur & </s> <s xml:id="echoid-s6715" xml:space="preserve">de même baſe n’a été qu’à 187 au lieu de 200 qu’elle <lb/>auroit dû porter; </s> <s xml:id="echoid-s6716" xml:space="preserve">cette difference vient apparemment de ce que <pb o="19" file="0303" n="314" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> le bois n’étoit pas tout-à-fait ſi bon que celui de la premiere Ex-<lb/>perience.</s> <s xml:id="echoid-s6717" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div319" type="section" level="2" n="110"> <head xml:id="echoid-head256" style="it" xml:space="preserve">Sixiéme Experience.</head> <p> <s xml:id="echoid-s6718" xml:space="preserve">Une Solive de trois pieds de longueur & </s> <s xml:id="echoid-s6719" xml:space="preserve">d’un pouce en quarré,</s> </p> <note position="right" xml:space="preserve">arrêtée par les deux bouts, a porté. . . # 285 # } # liv. <lb/>Une ſeconde poſée de même. . . . # 280 # # 283 <lb/>Une troiſiéme. . . . . . # 285 <lb/></note> <p> <s xml:id="echoid-s6720" xml:space="preserve">Les Solives de cette Experience ſe ſont rompuës en trois endroits <lb/>comme dans la ſeconde, & </s> <s xml:id="echoid-s6721" xml:space="preserve">leur force moyenne n’a été qu’à 283 <lb/>au lieu de 300 pour être dans le même raport avec la ſeconde Ex-<lb/>perience; </s> <s xml:id="echoid-s6722" xml:space="preserve">mais il n’eſt preſque pas poſſible que les Experiences puiſ-<lb/>ſent donner juſte ce que l’on devroit en attendre par raport à celles <lb/>qui ont été faites les premieres: </s> <s xml:id="echoid-s6723" xml:space="preserve">cependant l’on peut encore remar-<lb/>quer ici que la force moyenne des Solives de la 6<emph style="sub">e</emph> Experience eſt à <lb/>celle des Solives de la 5<emph style="sub">e</emph>, à peu près comme 3 à 2, puiſqu’il ne s’en <lb/>faut que trois unités que ce raport ſoit exact, par conſequent <lb/>c’eſt un ſurcroît de preuve que les poutres qui ne ſont poſées ſeule-<lb/>ment que ſur deux apuis ont moins de force d’un tiers que celles <lb/>qui ſont ſerrées par les bouts.</s> <s xml:id="echoid-s6724" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div320" type="section" level="2" n="111"> <head xml:id="echoid-head257" style="it" xml:space="preserve">Septiéme Experience.</head> <p> <s xml:id="echoid-s6725" xml:space="preserve">Une Solive de trois pieds de long ſur deux pouces en quarré, non</s> </p> <note position="right" xml:space="preserve">ar rêtée par les deux bouts, a porté. . . # 1550 # } # liv. <lb/>Une ſeconde ſemblable & poſée de même. . # 1620 # # 1585 <lb/>Une troiſieme. . . . . . # 1250 <lb/></note> <p> <s xml:id="echoid-s6726" xml:space="preserve">La premiere & </s> <s xml:id="echoid-s6727" xml:space="preserve">la ſeconde Solive de cette Experience ont porté <lb/>à peu près le poids qui devoit exprimer leur force par raport à la <lb/>premiere & </s> <s xml:id="echoid-s6728" xml:space="preserve">la cinquiéme Experience; </s> <s xml:id="echoid-s6729" xml:space="preserve">cependant la premiere Solive <lb/>a porté 50 liv. </s> <s xml:id="echoid-s6730" xml:space="preserve">de moins & </s> <s xml:id="echoid-s6731" xml:space="preserve">la ſeconde 20 liv. </s> <s xml:id="echoid-s6732" xml:space="preserve">de plus, puiſque le <lb/>poids devoit être de 1600 liv.</s> <s xml:id="echoid-s6733" xml:space="preserve">: quant à la troiſieme Solive, il s’en faut <lb/>beaucoup qu’elle ait eû toute ſa force, puiſqu’elle n’a porté que <lb/>1250 liv.</s> <s xml:id="echoid-s6734" xml:space="preserve">; il eſt vrai qu’elle a paru défectueuſe avant même d’en <lb/>avoir fait uſage, & </s> <s xml:id="echoid-s6735" xml:space="preserve">on n’a pas été ſurpris de ce qui eſt arrivé. <lb/></s> <s xml:id="echoid-s6736" xml:space="preserve">Cependant, comme il ne reſtoit point de bois debité ſelon ces di-<lb/>menſions-là, j’ai ſupoſé, pour trouver la force moyenne, que la troi-<lb/>ſiéme Solive avoit porté la moitié de la ſomme des poids de la <lb/>premiere & </s> <s xml:id="echoid-s6737" xml:space="preserve">de la ſeconde.</s> <s xml:id="echoid-s6738" xml:space="preserve"/> </p> <pb o="20" file="0304" n="315" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div321" type="section" level="2" n="112"> <head xml:id="echoid-head258" style="it" xml:space="preserve">Huitiéme Experience.</head> <p> <s xml:id="echoid-s6739" xml:space="preserve">Une Solive de trois pieds de long ſur 20 à 28 lignes de baſe,</s> </p> <note position="right" xml:space="preserve">poſée de cant, a porté. . . . . # 1665 # } # liv. <lb/>Une ſeconde ſemblable poſée de même. . # 1675 # # 1660 <lb/>Une troiſieme. . . . . . # 1640 <lb/></note> <p> <s xml:id="echoid-s6740" xml:space="preserve">J’ai eu deſſein par cette Experience de voir de combien à peu-<lb/>près une Solive, qui auroit les dimenſions de ſa baſe dans le raport <lb/>de 5 à 7, auroit plus de force qu’une autre dont la baſe ſeroit <lb/>quarrée, comme dans la ſeptiéme Experience, & </s> <s xml:id="echoid-s6741" xml:space="preserve">j’ai été convaincu <lb/>de ce que nous avons inſinué cy-devant, puiſque la force moyenne <lb/>des Solives de la ſeptiéme Experience n’eſt que de 1585 liv. </s> <s xml:id="echoid-s6742" xml:space="preserve">tan-<lb/>dis que celle des Solives de la derniere eſt de 1660 qui eſt une <lb/>difference de 75: </s> <s xml:id="echoid-s6743" xml:space="preserve">cela ne donne pas au juſte le raport de 245 à <lb/>216, dont nous avons fait mention dans le Chapitre précedent, <lb/>mais ſuffit pour la juſtification de la Théorie.</s> <s xml:id="echoid-s6744" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6745" xml:space="preserve">Je n’ai point fait d’Experiences ſur les Solives arrêtées par un <lb/>bout ſeulement, parce qu’il m’a paru qu’elles auroient éte inuti-<lb/>les; </s> <s xml:id="echoid-s6746" xml:space="preserve">celles que je viens de raporter étant ſuffiſantes pour établir <lb/>les regles dont il va être queſtion: </s> <s xml:id="echoid-s6747" xml:space="preserve">je n’en ai pas fait non plus avec <lb/>d’autres bois que celui de chêne; </s> <s xml:id="echoid-s6748" xml:space="preserve">mais, comme Mr. </s> <s xml:id="echoid-s6749" xml:space="preserve">Parent en a <lb/>fait non ſeulement ſur le chêne, mais auſſi ſur le ſapin, il ne ſera <lb/>pas inutile que je diſe, qu’il s’eſt aperçu que la force moyenne du <lb/>ſapin étoit à celle du chêne, comme 119. </s> <s xml:id="echoid-s6750" xml:space="preserve">eſt à 100. </s> <s xml:id="echoid-s6751" xml:space="preserve">ou environ <lb/>comme 6. </s> <s xml:id="echoid-s6752" xml:space="preserve">eſt à 5. </s> <s xml:id="echoid-s6753" xml:space="preserve">d’où l’on peut conclure, que quand une certaine <lb/>Solive de chêne portera 500. </s> <s xml:id="echoid-s6754" xml:space="preserve">livres avant l’inſtant de ſe rompre, <lb/>une autre de ſapin toute ſemblable à celle-ci en portera 600. </s> <s xml:id="echoid-s6755" xml:space="preserve">c’eſt-<lb/>à-dire un cinquiéme en ſus de plus que le chêne: </s> <s xml:id="echoid-s6756" xml:space="preserve">par conſequent, <lb/>quand il s’agira du bois de ſapin, il ſera aiſé de calculer ſa force <lb/>par la connoiſſance que les Experiences precedentes nous ont don-<lb/>nées de celles du chêne.</s> <s xml:id="echoid-s6757" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6758" xml:space="preserve">Etant prévenu par la ſeconde Experience, qu’une Solive de 18. <lb/></s> <s xml:id="echoid-s6759" xml:space="preserve">pouces de longueur & </s> <s xml:id="echoid-s6760" xml:space="preserve">d’un pouce en quarré, ſerrée par les deux <lb/>bouts, peut porter 600. </s> <s xml:id="echoid-s6761" xml:space="preserve">livres avant l’inſtant de ſa rupture, il s’en-<lb/>ſuit qu’une autre auſſi d’un pouce en quarré, & </s> <s xml:id="echoid-s6762" xml:space="preserve">qui auroit 3. </s> <s xml:id="echoid-s6763" xml:space="preserve">pieds <lb/>ou 36. </s> <s xml:id="echoid-s6764" xml:space="preserve">pouces de longueur, & </s> <s xml:id="echoid-s6765" xml:space="preserve">ſerrée par ſes deux extrêmités, ne <lb/>portera que 300, ce qui eſt confirmé par la ſixiéme Experience: </s> <s xml:id="echoid-s6766" xml:space="preserve"><lb/>or puiſque la force de deux Solives de même longueur eſt dans le <lb/>raport du quarré de la hauteur de chacune, multiplié par la lar-<lb/>geur de la baſe; </s> <s xml:id="echoid-s6767" xml:space="preserve">ſi de ces deux ſolives la baſe de l’une a un pouce <pb o="21" file="0305" n="316" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> en quarré, & </s> <s xml:id="echoid-s6768" xml:space="preserve">la baſe de l’autre 6. </s> <s xml:id="echoid-s6769" xml:space="preserve">pouces auſſi en quarré, leur for-<lb/>ce ſera dans le raport des cubes des côtés de leur baſes: </s> <s xml:id="echoid-s6770" xml:space="preserve">par con-<lb/>ſequent comme un eſt à 216. </s> <s xml:id="echoid-s6771" xml:space="preserve">ainſi la Solive d’un pouce en quarré <lb/>& </s> <s xml:id="echoid-s6772" xml:space="preserve">de 3. </s> <s xml:id="echoid-s6773" xml:space="preserve">pieds de longueur portant 300. </s> <s xml:id="echoid-s6774" xml:space="preserve">livres, arrêtée par les <lb/>deux bouts, celle qui auroit 3. </s> <s xml:id="echoid-s6775" xml:space="preserve">pieds en longueur & </s> <s xml:id="echoid-s6776" xml:space="preserve">6. </s> <s xml:id="echoid-s6777" xml:space="preserve">pouces <lb/>en quarré portera donc 64800. </s> <s xml:id="echoid-s6778" xml:space="preserve">mais comme cette derniere Solive <lb/>eſt très commode, pour ſervir de modêle dans la maniere de con-<lb/>noître la force du bois, nous nous en ſervirons préférablement <lb/>à toute autre, pour les operations ſuivantes; </s> <s xml:id="echoid-s6779" xml:space="preserve">c’eſt-à-dire, que nous <lb/>regarderons comme indubitable, qu’une Solive de 3. </s> <s xml:id="echoid-s6780" xml:space="preserve">pieds de <lb/>longueur & </s> <s xml:id="echoid-s6781" xml:space="preserve">de 6. </s> <s xml:id="echoid-s6782" xml:space="preserve">pouces en quarré porte dans ſon milieu 64800 <lb/>avant l’inſtant de ſe rompre, lors qu’elle eſt parfaitement ſerrée <lb/>par les deux bouts.</s> <s xml:id="echoid-s6783" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6784" xml:space="preserve">Preſentement, ſi l’on avoit une poutre de 30. </s> <s xml:id="echoid-s6785" xml:space="preserve">pieds de lon-<lb/>gueur entre ſes deux apuis, & </s> <s xml:id="echoid-s6786" xml:space="preserve">de 12. </s> <s xml:id="echoid-s6787" xml:space="preserve">pouces en quarré, dont les <lb/>extrêmités ſeroient bien engagées & </s> <s xml:id="echoid-s6788" xml:space="preserve">ſerrées dans deux murs, & </s> <s xml:id="echoid-s6789" xml:space="preserve"><lb/>qu’on voulut ſavoir qu’elle eſt la charge que peut porter cette <lb/>poutre dans ſon milieu, avant l’inſtant de ſe rompre; </s> <s xml:id="echoid-s6790" xml:space="preserve">il faut com-<lb/>mencer par diviſer 216. </s> <s xml:id="echoid-s6791" xml:space="preserve">par 3. </s> <s xml:id="echoid-s6792" xml:space="preserve">c’eſt-à-dire, le cube de la hauteur de <lb/>la Solive, qui doit ſervir de modele par ſa longueur, & </s> <s xml:id="echoid-s6793" xml:space="preserve">le quo-<lb/>tient ſera 72. </s> <s xml:id="echoid-s6794" xml:space="preserve">qui doit ſervir de premier terme à une regle de pro-<lb/>portion, dont le ſecond ſera le poids que peut porter cette ſolive, <lb/>c’eſt-à-dire, 64800. </s> <s xml:id="echoid-s6795" xml:space="preserve">pour avoir le troiſiéme terme, il faut quarrer <lb/>la hauteur de la poutre dont il eſt queſtion, multiplier ce quarré <lb/>par la largeur de la baſe, diviſer enſuite le produit qui eſt ici 1728. <lb/></s> <s xml:id="echoid-s6796" xml:space="preserve">par la longueur de la poutre, qu’on ſupoſe être de 30. </s> <s xml:id="echoid-s6797" xml:space="preserve">pieds, <lb/>& </s> <s xml:id="echoid-s6798" xml:space="preserve">en prendre le quotient; </s> <s xml:id="echoid-s6799" xml:space="preserve">faiſant la regle comme à l’ordinaire, <lb/>le quatriéme terme donnera le poids que doit porter la poutre, <lb/>qui ſe trouvera de 51840.</s> <s xml:id="echoid-s6800" xml:space="preserve">, on aura de même la force de toute au-<lb/>tre poutre, dont les dimenſions ſeroient telles qu’on voudra.</s> <s xml:id="echoid-s6801" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6802" xml:space="preserve">Si la poutre, dont on demande la force, n’étoit point ſerrée par <lb/>ſes deux bouts, mais ſeulement poſée ſur deux apuis; </s> <s xml:id="echoid-s6803" xml:space="preserve">on pourra <lb/>faire la même regle que ci-deſſus, & </s> <s xml:id="echoid-s6804" xml:space="preserve">prendre les deux tiers du <lb/>poids que le calcul aura donné, puiſque l’on ſait qu’une poutre <lb/>dans cette ſituation porte un tiers moins que la précédente.</s> <s xml:id="echoid-s6805" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6806" xml:space="preserve">Nous avons ſupoſé juſqu’ici, que le poids étoit toûjours poſé <lb/>dans le milieu; </s> <s xml:id="echoid-s6807" xml:space="preserve">ce pendant, comme il peut ſe rencontrer dans d’au-<lb/>tres endroits, voici une maniere de connoître la charge que por-<lb/>tera une poutre, à tel point qu’on voudra de ſa longueur, pour <lb/>qu’elle reſiſte autant qu’elle le feroit ſi elle étoit chargée dans le <lb/>milieu.</s> <s xml:id="echoid-s6808" xml:space="preserve"/> </p> <pb o="22" file="0306" n="317" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s6809" xml:space="preserve">Supofant une poutre AB, de 24. </s> <s xml:id="echoid-s6810" xml:space="preserve">pieds de longueur, & </s> <s xml:id="echoid-s6811" xml:space="preserve">de 10. <lb/></s> <s xml:id="echoid-s6812" xml:space="preserve"> <anchor type="note" xlink:label="note-0306-01a" xlink:href="note-0306-01"/> pouces ſur 14. </s> <s xml:id="echoid-s6813" xml:space="preserve">d’équariſſage, poſée de cant, & </s> <s xml:id="echoid-s6814" xml:space="preserve">ſerrée par ſes deux <lb/>bouts, on demande quel poids elle peut porter aux deux tiers de <lb/>ſa longueur, avant l’inſtant de ſe rompre; </s> <s xml:id="echoid-s6815" xml:space="preserve">pour cela, il faut com-<lb/>mencer par chercher la peſanteur du poids E, qu’elle portera dans <lb/>ſon milieu, & </s> <s xml:id="echoid-s6816" xml:space="preserve">on trouvera qu’il eſt de 73500. </s> <s xml:id="echoid-s6817" xml:space="preserve">livres: </s> <s xml:id="echoid-s6818" xml:space="preserve">or ſi on ſe <lb/>rapelle que l’action de ce poids eſt partagée en trois, dont un tiers <lb/>agit à l’extrêmité A, un autre à l’extrêmité B, & </s> <s xml:id="echoid-s6819" xml:space="preserve">le troiſiéme dans <lb/>le milieu D, l’on verra qu’aſin que la poutre ſoit chargée aux deux <lb/>tiers C, comme elle le ſeroit dans le milieu, avec le poids de <lb/>73500. </s> <s xml:id="echoid-s6820" xml:space="preserve">il faut que chaque bout ſoit tiré de la même façon, c’eſt <lb/>pourquoi je multiplie 24500. </s> <s xml:id="echoid-s6821" xml:space="preserve">qui eſt le tiers du poids E, par 12. <lb/></s> <s xml:id="echoid-s6822" xml:space="preserve">qui eſt la longueur du bras de levier AD, ou BD, qui répond aux <lb/>extrêmités, & </s> <s xml:id="echoid-s6823" xml:space="preserve">diviſe le produit par les deux-tiers de la longueur <lb/>de la poutre, qui expriment alors le bras de levier CB, qui répond <lb/>au bout B, & </s> <s xml:id="echoid-s6824" xml:space="preserve">le quotient 18375. </s> <s xml:id="echoid-s6825" xml:space="preserve">eſt la partie du poids qui doit agir <lb/>à l’extrêmité C de ce levier, pour faire le même effet que le tiers du <lb/>poids E, fait en D pour avoir la partie du poids qui doit tirer l’au-<lb/>tre bout A, de la même façon que l’eſt le précédent, je multiplie <lb/>encore 24500. </s> <s xml:id="echoid-s6826" xml:space="preserve">par 12. </s> <s xml:id="echoid-s6827" xml:space="preserve">& </s> <s xml:id="echoid-s6828" xml:space="preserve">diviſe le produit par l’autre tiers AC, de <lb/>la longueur de la poutre, c’eſt-à-dire, par 8. </s> <s xml:id="echoid-s6829" xml:space="preserve">pour avoir 36750. </s> <s xml:id="echoid-s6830" xml:space="preserve"><lb/>qui eſt ce que l’on demande; </s> <s xml:id="echoid-s6831" xml:space="preserve">enfin comme les deux bouts ne <lb/>pouvoient être rompus ci-devant que par l’action du tiers qui agit <lb/>dans le milieu, il faut donc fupoſer que la poutre eſt encore char-<lb/>gée au point C, du poids de 24500. </s> <s xml:id="echoid-s6832" xml:space="preserve">ainſi ajoûtant ce nombre avec <lb/>les deux précedens, c’eſt-à-dire, avec 18375. </s> <s xml:id="echoid-s6833" xml:space="preserve">& </s> <s xml:id="echoid-s6834" xml:space="preserve">36750. </s> <s xml:id="echoid-s6835" xml:space="preserve">l’on aura <lb/>79625. </s> <s xml:id="echoid-s6836" xml:space="preserve">pour la valeur du poids G, que la poutre peut porter à <lb/>l’endroit C pour être chargée de la même façon qu’elle le ſeroit ſi <lb/>elle avoit porté dans ſon milieu le poids E de 73500. </s> <s xml:id="echoid-s6837" xml:space="preserve">qui n’eſt <lb/>ici qu’imaginaire, puiſqu’il en faut faire abſtraction, & </s> <s xml:id="echoid-s6838" xml:space="preserve">ne conſide-<lb/>rer la poutre chargée que du ſeul poids G.</s> <s xml:id="echoid-s6839" xml:space="preserve"/> </p> <div xml:id="echoid-div321" type="float" level="3" n="1"> <note position="left" xlink:label="note-0306-01" xlink:href="note-0306-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 12.</note> </div> <p> <s xml:id="echoid-s6840" xml:space="preserve">Si on vouloit charger une poutre de pluſieurs poids, poſés à <lb/>differens endroits de ſa longueur, & </s> <s xml:id="echoid-s6841" xml:space="preserve">qu’on deſirât ſavoir quel rap-<lb/>port il y a de cette charge avec celle que la poutre peut porter <lb/>avant l’inſtant de ſe rompre, il faudra commencer par chercher <lb/>quel eſt le poids que cette poutre peut porter dans le milieu, en-<lb/>ſuite ſupoſer qu’on a réuni tous les poids dont il eſt queſtion dans <lb/>le même milieu, alors on pourra comparer ce poids avec celui <lb/>que la poutre eſt capable de ſoûtenir, & </s> <s xml:id="echoid-s6842" xml:space="preserve">l’on verra s’il eſt plus <lb/>grand ou plus petit, pour juger du parti qu’il faudra prendre.</s> <s xml:id="echoid-s6843" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6844" xml:space="preserve">Comme il ne conviendroit pas de charger les poutres de tout <pb o="23" file="0307" n="318" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> le poids qu’elles peuvent porter avant l’inſtant de ſe rompre, puis <lb/>qu’elles ſe romproient effectivement, & </s> <s xml:id="echoid-s6845" xml:space="preserve">ne pourroient plus être <lb/>d’uſage; </s> <s xml:id="echoid-s6846" xml:space="preserve">je croi que, pour agir en toute ſureté, & </s> <s xml:id="echoid-s6847" xml:space="preserve">ne les point for-<lb/>cer, on ne doit les charger au plus dans le milieu, qui eſt l’endroit <lb/>le plus foible, qu’environ de la moitié du poids ſous lequel elles <lb/>pourroient être rompuës; </s> <s xml:id="echoid-s6848" xml:space="preserve">ainſi, ayant trouvé par le calcul pré-<lb/>cedent, qu’une poutre qui auroit 24. </s> <s xml:id="echoid-s6849" xml:space="preserve">pieds de long, ſur 10. </s> <s xml:id="echoid-s6850" xml:space="preserve">à 14. <lb/></s> <s xml:id="echoid-s6851" xml:space="preserve">pouces d’équariſſage & </s> <s xml:id="echoid-s6852" xml:space="preserve">poſée de cant, peut ſoûtenir dans le mi-<lb/>lieu de ſa longueur, un poids de 73500. </s> <s xml:id="echoid-s6853" xml:space="preserve">on ne doit charger cette <lb/>poutre au plus que de 36750. </s> <s xml:id="echoid-s6854" xml:space="preserve">on peut d’autant mieux compter <lb/>ſur cette regle, qu’il n’arrive jamais que le poids dont on charge <lb/>les planchers que ſoutiennent les poutres, ſoit parfaitement réuni <lb/>dans le milieu, comme s’il y étoit ſuſpendu à l’aide de quelque <lb/>cordage, puiſque les corps peſans ont toûjours un certain volu-<lb/>me qui occupe une partie de la longueur de la poutre, & </s> <s xml:id="echoid-s6855" xml:space="preserve">dimi-<lb/>nuë par conſequent du bras de levier, ce qui fait qu’elles reſiſtent <lb/>avec plus d’avantage, & </s> <s xml:id="echoid-s6856" xml:space="preserve">ſe reſſentent moins du fardeau qu’elles <lb/>portent.</s> <s xml:id="echoid-s6857" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6858" xml:space="preserve">Nous ſupoſons ici que les poutres portent tout le poids dont les <lb/>planchers peuvent être chargés; </s> <s xml:id="echoid-s6859" xml:space="preserve">car quand même le poids ſeroit <lb/>ſur les ſolives entre deux poutres, ces ſolives étant apuyées ſur les <lb/>poutres, c’eſt toûjours ſur elles que ſe termine toute la charge; <lb/></s> <s xml:id="echoid-s6860" xml:space="preserve">auſſi quand les planchers viennent à manquer, ce n’eſt jamais que <lb/>par-là & </s> <s xml:id="echoid-s6861" xml:space="preserve">rarement par les ſolives, parce qu’elles n’ont pas beau-<lb/>coup de portée; </s> <s xml:id="echoid-s6862" xml:space="preserve">mais s’il falloit avoir égard à leur force, on pourra <lb/>connoître la réſiſtance dont elles ſeront capables comme on a fait <lb/>pour les poutres, avec cette attention cependant qu’on doit les re-<lb/>garder comme des pieces poſées ſur deux apuys ſans y être ſerrées <lb/>par les extremités, & </s> <s xml:id="echoid-s6863" xml:space="preserve">que par conſequent elles ont un tiers moins <lb/>de force à proportion que les poutres.</s> <s xml:id="echoid-s6864" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6865" xml:space="preserve">N’ayant parlé juſqu’ici que des poutres dont les dimenſions étoient <lb/>connuës, il nous reſte à examiner comme on peut trouver quelle <lb/>doit être la groſſeur d’un arbre dont on voudroit tirer une poutre <lb/>qui fut la plus forte de toutes celles que peut fournir le même arbre, <lb/>& </s> <s xml:id="echoid-s6866" xml:space="preserve">qui ſoit en même tems capable de porter dans ſon milieu un poids <lb/>donné. </s> <s xml:id="echoid-s6867" xml:space="preserve">Il eſt conſtant qu’ayant deux arbres dont les diamétres AB & </s> <s xml:id="echoid-s6868" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0307-01a" xlink:href="note-0307-01"/> GH, ſont inégaux, que voulant en tirer les deux plus fortes poutres <lb/>qu’ils peuvent donner, ces poutres auront des baſes ſemblables, <lb/>puiſque les rectangles FE & </s> <s xml:id="echoid-s6869" xml:space="preserve">KI, auront été tracés de la même ma-<lb/>niere. </s> <s xml:id="echoid-s6870" xml:space="preserve">Or ſi les poutres ont des longueurs égales, leurs forces ſeront <lb/>commeles parallelipipedes, comprisſousle quarré du côté FB, & </s> <s xml:id="echoid-s6871" xml:space="preserve">le <pb o="24" file="0308" n="319" rhead="LA SCIENCE DES INGENIEURS,"/> côté FA, eſt au parallelipipede, compris ſous le quarré du côté <lb/>KH, & </s> <s xml:id="echoid-s6872" xml:space="preserve">la ligne KG; </s> <s xml:id="echoid-s6873" xml:space="preserve">mais GI, étant à GK, :</s> <s xml:id="echoid-s6874" xml:space="preserve">: AE, AF, il s’en-<lb/>ſuit que ces parallelipipedes ſeront ſemblables, & </s> <s xml:id="echoid-s6875" xml:space="preserve">dans la raiſon <lb/>des cubes de leurs côtés homologues FB, & </s> <s xml:id="echoid-s6876" xml:space="preserve">KH, ou bien dans la <lb/>raiſon des cubes des diamêtres ou diagonales AB, & </s> <s xml:id="echoid-s6877" xml:space="preserve">GH, à cauſe <lb/>des triangles ſemblables AFB, & </s> <s xml:id="echoid-s6878" xml:space="preserve">GKH, par conſequent l’on pour-<lb/>ra prendre les cubes des diamêtres, au lieu des parallelipipedes <lb/>pour exprimer la force des deux poutres, en ſupoſant toûjours que <lb/>leurs longueurs ſont égales; </s> <s xml:id="echoid-s6879" xml:space="preserve">mais ſi elles étoient differentes, on <lb/>connoîtra encore le rapport de leur force, en diviſant le cube de <lb/>chaque diametre par la longueur de la poutre qui luy répond.</s> <s xml:id="echoid-s6880" xml:space="preserve"/> </p> <div xml:id="echoid-div322" type="float" level="3" n="2"> <note position="right" xlink:label="note-0307-01" xlink:href="note-0307-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 9. <lb/>& 10.</note> </div> <p> <s xml:id="echoid-s6881" xml:space="preserve">Si l’on ſupoſe preſentement qu’on a tiré du cercle FE une poutre <lb/>dont on connoît la longueur, la baſe FE & </s> <s xml:id="echoid-s6882" xml:space="preserve">le poids que cette pou-<lb/>tre peut porter avant l’inſtant de ſe rompre, & </s> <s xml:id="echoid-s6883" xml:space="preserve">qu’on veuille ſavoir <lb/>quel doit être le diamêtre de l’arbre d’où l’on veut tirer une autre <lb/>poutre dont la baſe ſoit ſemblable à la precedente, enſorte que <lb/>cette poutre ſoit capable de porter un poids donné, il faut chercher <lb/>par l’Algebre une formule qui nous enſeigne la maniere dont il <lb/> <anchor type="note" xlink:label="note-0308-01a" xlink:href="note-0308-01"/> faudra s’y prendre.</s> <s xml:id="echoid-s6884" xml:space="preserve"/> </p> <div xml:id="echoid-div323" type="float" level="3" n="3"> <note position="left" xlink:label="note-0308-01" xlink:href="note-0308-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> <p> <s xml:id="echoid-s6885" xml:space="preserve">Prenant la poutre NP pour celle qui doit ſervir de modele, nous <lb/>nommerons la diagonale OQ, a; </s> <s xml:id="echoid-s6886" xml:space="preserve">ſa longueur NO, b; </s> <s xml:id="echoid-s6887" xml:space="preserve">& </s> <s xml:id="echoid-s6888" xml:space="preserve">le poids <lb/>qu’elle peut porter m; </s> <s xml:id="echoid-s6889" xml:space="preserve">de même nous nommerons x, la diagonale <lb/>de la baſe que l’on cherche, d, la longueur de la poutre qui apar-<lb/>tient à cette baſe, & </s> <s xml:id="echoid-s6890" xml:space="preserve">n, le poids donné; </s> <s xml:id="echoid-s6891" xml:space="preserve">& </s> <s xml:id="echoid-s6892" xml:space="preserve">alors on aura m, n : </s> <s xml:id="echoid-s6893" xml:space="preserve">: <lb/></s> <s xml:id="echoid-s6894" xml:space="preserve">{a<emph style="sub">3</emph>/b} {x<emph style="sub">3</emph>/d}; </s> <s xml:id="echoid-s6895" xml:space="preserve">c’eſt-à-dire que le poids que peut porter la poutre NP, <lb/>eſt au poids que doit porter la poutre dont on demande la baſe, <lb/>comme le cube de la diagonale NQ, divifé par la longueur NO, <lb/>eſt au cube du diamêtre du cercle que l’on demande divifé par la <lb/>longueur de la poutre quirépond à ce diamêtre. </s> <s xml:id="echoid-s6896" xml:space="preserve">Or ſi de cette pro-<lb/>portion on en forme une équation on aura {na<emph style="super">2</emph>/b} = {mx<emph style="sub">3</emph>/d} qui étant <lb/>diviſée par m, & </s> <s xml:id="echoid-s6897" xml:space="preserve">multipliée par d, aſin de dégager l’inconnuë il vient <lb/>{dna<emph style="sub">3</emph>/bm} = x<emph style="sub">3</emph> dont extrayant la racine cube, l’on a {√<emph style="sub">3</emph>dna<emph style="super">3</emph>\x{0020}/bm} = x, <lb/>qui donne la valeur de l’inconnuë, que l’on trouvera en ſuivant <lb/>ce qu’enſeignent les lettres qui compoſent le premier membre, <lb/>comme nous allons le détailler.</s> <s xml:id="echoid-s6898" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6899" xml:space="preserve">Supoſant que la poutre NP, qui doit ſervir de modele, ſoit de <lb/>24 pieds de longueur, ſa hauteur OP de 14 pouces, & </s> <s xml:id="echoid-s6900" xml:space="preserve">la largeur <lb/>PQ de 10, le quarré de 14 étant à peu-près double de celui de 10, <pb o="25" file="0309" n="320" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> le rectangle RP, pourra être conſideré comme ſemblable à celui <lb/>que nous cherchons, & </s> <s xml:id="echoid-s6901" xml:space="preserve">comme l’on a le rectangle OPQ, il ſera aiſé <lb/>d’avoir la diagonale OQ, qu’on trouvera environ de 17 pouces <lb/>3 lignes, qui eſt la valeur de a; </s> <s xml:id="echoid-s6902" xml:space="preserve">ainſi cubant ce nombre l’on aura <lb/>5132 = a<emph style="sub">3</emph>, 24 = b; </s> <s xml:id="echoid-s6903" xml:space="preserve">& </s> <s xml:id="echoid-s6904" xml:space="preserve">comme nous avons vû ci-devant, qu’une <lb/>poutre telle que celle-ci pouvoit porter dans ſon milieu 73500 <lb/>liv. </s> <s xml:id="echoid-s6905" xml:space="preserve">avant l’inſtant de ſe rompre lorſqu’elle étoit bien ſerrée par ſes <lb/>extrêmités, on aura donc 73500 = m, par conſequent la valeur <lb/>des trois quantités qui apartiennent à la poutre qui doit ſervir de <lb/>modele; </s> <s xml:id="echoid-s6906" xml:space="preserve">& </s> <s xml:id="echoid-s6907" xml:space="preserve">ſi la poutre dont on cherche la baſe a 30 pieds de lon-<lb/>gueur, on aura 30 = d, & </s> <s xml:id="echoid-s6908" xml:space="preserve">il ne reſtera plus qu’à ſavoir quel eſt le <lb/>poids qu’on veut faire porter à cette poutre, & </s> <s xml:id="echoid-s6909" xml:space="preserve">de quelle façon on <lb/>veut qu’elle le porte; </s> <s xml:id="echoid-s6910" xml:space="preserve">car ou l’action de ce poids ſera en équilibre <lb/>avec la réſiſtance de la poutre & </s> <s xml:id="echoid-s6911" xml:space="preserve">même un peu plus fort que cette <lb/>réſiſtance pour cauſer la rupture, ou bien la réſiſtance de la poutre <lb/>ſera tellement au-deſſus du poids, qu’on n’aura pas lieu d’aprehender <lb/>qu’elle caſſe, qui eſt le cas qui convient à l’uſage, puiſqu’on ne fait <lb/>pas des poutres pour les rompre, & </s> <s xml:id="echoid-s6912" xml:space="preserve">comme j’ai dit ailleurs qu’il <lb/>ne falloit les charger que de la moitié du poids qu’elles pouvoient <lb/>porter avant l’inſtant de ſe rompre, il faut donc pour ſuivre ceprin-<lb/>cipe faire comme ſi la poutre dont on cherche la baſe devoit porter <lb/>un poids double de celui qu’elle portera en effet, parce qu’alors ſa <lb/>réſiſtance ſera double de l’effort qu’elle aura à ſoûtenir, c’eſt pour-<lb/>quoi voulant qu’elle puiſſe porter 100000l. </s> <s xml:id="echoid-s6913" xml:space="preserve">nous ſupoſerons qu’elle <lb/>peut en porter 200000, ainſi on aura 200000 = n, qui eſt la va-<lb/>leur de la derniere lettre qui nous reſtoit à connoître.</s> <s xml:id="echoid-s6914" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6915" xml:space="preserve">Pour ſuivre ce qu’enſeigne la formule {<emph style="sub">3</emph>√dna<emph style="sub">3</emph>\x{0020}/bm} = x, on com-<lb/>mencera par multiplier la valeur de d & </s> <s xml:id="echoid-s6916" xml:space="preserve">de n, l’une par l’autre, qui <lb/>donneront 6000000 qu’il faut multiplier par la valeur de a<emph style="sub">3</emph>, l’on <lb/>aura 30792000000 = dna<emph style="sub">3</emph>, qu’il faut diviſer par la valeur de bm; <lb/></s> <s xml:id="echoid-s6917" xml:space="preserve">c’eſt-à-dire par le produit de 24 & </s> <s xml:id="echoid-s6918" xml:space="preserve">de 73500 qui eſt 1764000, & </s> <s xml:id="echoid-s6919" xml:space="preserve">le <lb/>quotient donnera 17455 = {dna<emph style="sub">3</emph>/bm}, dont il faut extraire la racine <lb/>cube qui ſera à peu-près de 25 pouces 6 lignes pour la valeur de <lb/>x; </s> <s xml:id="echoid-s6920" xml:space="preserve">c’eſt-à-dire pour le diamétre de l’arbre d’où l’on veut tirer la <lb/>poutre que l’on demande.</s> <s xml:id="echoid-s6921" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6922" xml:space="preserve">Si l’on vouloit ſavoir en nombre quelle eſt la valeur des deux côtés <lb/>GI & </s> <s xml:id="echoid-s6923" xml:space="preserve">IH, de la baſe de la poutre qu’on doit tirer du cercle KI, <lb/>dont le diamétre GH, eſt de 25 pouces & </s> <s xml:id="echoid-s6924" xml:space="preserve">demi, remarqués que le <lb/>quarré du côté GI, étant double de celui du côté IH, le premier <pb o="26" file="0310" n="321" rhead="LA SCIENCE DES INGENIEURS,"/> ſera les deux tiers du quarré du diamêtre GH, & </s> <s xml:id="echoid-s6925" xml:space="preserve">le ſecond le tiers <lb/>même, ainſi quarrant 25 & </s> <s xml:id="echoid-s6926" xml:space="preserve">demi ſi l’on prend à part le tiers & </s> <s xml:id="echoid-s6927" xml:space="preserve">les <lb/>deux tiers du produit, & </s> <s xml:id="echoid-s6928" xml:space="preserve">qu’on extraye la racine quarrée de chacune <lb/>de ces quantités, elles donneront à peu-prés 14 pouces 8 lignes, <lb/>& </s> <s xml:id="echoid-s6929" xml:space="preserve">20 pouces 8 lignes, pour la valeur des côtés GI & </s> <s xml:id="echoid-s6930" xml:space="preserve">IH, c’eſt-à-<lb/>dire pour les dimenſions de l’équarriſſage.</s> <s xml:id="echoid-s6931" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6932" xml:space="preserve">Ileſt bon de dire que toutes les fois que nous avons parlé du cer-<lb/>cle d’un arbre, nous avons toûjours entendu la partie interieure de <lb/>l’arbre, qui n’a ni aubier ni écorce, mais qui eſt dure & </s> <s xml:id="echoid-s6933" xml:space="preserve">de bonne <lb/>conſiſtance; </s> <s xml:id="echoid-s6934" xml:space="preserve">& </s> <s xml:id="echoid-s6935" xml:space="preserve">que quand il étoit queſtion d’en tirer une poutre, <lb/>on commençoit à tracer avec le compas un cercle dont le centre <lb/>étoit celui de l’arbre même, & </s> <s xml:id="echoid-s6936" xml:space="preserve">dont le rayon alloit ſe terminer un <lb/>peu au-deſſous de l’écorce; </s> <s xml:id="echoid-s6937" xml:space="preserve">& </s> <s xml:id="echoid-s6938" xml:space="preserve">que c’étoit le diamétre de ce cercle <lb/>là qu’il falloit diviſer en trois parties égales, pour tracer la baſe de <lb/>la poutre que l’on demande: </s> <s xml:id="echoid-s6939" xml:space="preserve">de même, après avoir trouvé le diamé-<lb/>tre d’un arbre duquel on veut tirer une poutre, comme dans l’opé-<lb/>ration précédente, il faut toûjours ſupoſer que l’arbre doit avoir <lb/>au moins un diamétre de 3 pouces plus grand que celui qu’on aura <lb/>trouvé, afin d’avoir égard au déchet.</s> <s xml:id="echoid-s6940" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6941" xml:space="preserve">Voici encore un cas que je ne paſſerai pas ſous ſilence, eſpe-<lb/>rant qu’il ſervira dans les occaſions qui peuvent ſe preſenter.</s> <s xml:id="echoid-s6942" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6943" xml:space="preserve">La longueur d’une poutre étant donnée, & </s> <s xml:id="echoid-s6944" xml:space="preserve">le côté ſur lequel elle <lb/>doit être poſée, on demande quelle doit être ſon épaiſſeur verticale, <lb/>pour être capable de porter dans ſon milieu un poids donné.</s> <s xml:id="echoid-s6945" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6946" xml:space="preserve">Pour cela, nous ſupoſerons que la poutre, qui doit ſervir de mo-<lb/>dele, a pour baſe un quarré, dont le côté ſera nommé a, la lon-<lb/>gueur de la poutre b, & </s> <s xml:id="echoid-s6947" xml:space="preserve">le poids qu’elle peut porter avant l’inſtant <lb/>de ſe rompre, m; </s> <s xml:id="echoid-s6948" xml:space="preserve">que la longueur de la poutre qui fait le ſujet de la <lb/>queſtion eſt nommée d; </s> <s xml:id="echoid-s6949" xml:space="preserve">le côté de la baſe que l’on connoît, c; <lb/></s> <s xml:id="echoid-s6950" xml:space="preserve">celui que l’on cherche, x; </s> <s xml:id="echoid-s6951" xml:space="preserve">& </s> <s xml:id="echoid-s6952" xml:space="preserve">le poids que cette poutre doit porter, <lb/>n: </s> <s xml:id="echoid-s6953" xml:space="preserve">cela poſe2;</s> <s xml:id="echoid-s6954" xml:space="preserve">, ſi on multiplie le quarré de la hauteur verticale de <lb/>chaque poutre par ſon épaiſſeur, & </s> <s xml:id="echoid-s6955" xml:space="preserve">que l’on diviſe chaque produit <lb/>par la longueur des poutres auſquelles elles appartiennent, on pour-<lb/>ra avec les deux quotiens, & </s> <s xml:id="echoid-s6956" xml:space="preserve">les poids que ces poutres peuvent por-<lb/>ter avant l’inſtant de ſe rompre, former cette proportion, m, n : </s> <s xml:id="echoid-s6957" xml:space="preserve">: </s> <s xml:id="echoid-s6958" xml:space="preserve"><lb/>{√a<emph style="sub">3</emph>\x{0020}/b}, {cxx/d} qui donne {na<emph style="super">3</emph>/b} = {mcxx/d}, & </s> <s xml:id="echoid-s6959" xml:space="preserve">multipliant cette équation par d, <lb/>& </s> <s xml:id="echoid-s6960" xml:space="preserve">la diviſant enſuite par mc, l’on aura après avoir extrait la racine <lb/>quarrée de chaque membre, {<emph style="sub">2</emph>√dna<emph style="sub">3</emph>\x{0020}/bcm} = x, qui eſt une formule, dont <lb/>voici l’application.</s> <s xml:id="echoid-s6961" xml:space="preserve"/> </p> <pb o="27" file="0311" n="322" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s6962" xml:space="preserve">Prenant pour modele la Solive de 3 pieds de longueur fur 6 <lb/>pouces en quarré, qui porte un poids de 64500 liv. </s> <s xml:id="echoid-s6963" xml:space="preserve">l’on aura <lb/>a<emph style="sub">3</emph> = 216, 6 = 3, m = 64500. </s> <s xml:id="echoid-s6964" xml:space="preserve">Si preſentement la poutre, dont il <lb/>eſt queſtion, a 24 pieds de longueur, que le côté ſur lequel elle doit <lb/>être poſée ſoit de 12 pouces, & </s> <s xml:id="echoid-s6965" xml:space="preserve">que le poids qu’elle doit porter pour <lb/>n’être pas en danger de ſe rompre, ſoit de 70000. </s> <s xml:id="echoid-s6966" xml:space="preserve">il faut doubler ce <lb/>poids, pour les raiſons que j’ai dit ci-devant, & </s> <s xml:id="echoid-s6967" xml:space="preserve">alors il ſera conſideré <lb/>comme étant de 140000. </s> <s xml:id="echoid-s6968" xml:space="preserve">Ainſi nous aurons donc d = 24, c = 12, <lb/>& </s> <s xml:id="echoid-s6969" xml:space="preserve">n = 140000; </s> <s xml:id="echoid-s6970" xml:space="preserve">c’eſt pourquoi il n’eſt plus queſtion que de ſuivre ce <lb/>qu’enſeigne la formule, c’eſt-à-dire multiplier les valeurs de d & </s> <s xml:id="echoid-s6971" xml:space="preserve">de <lb/>n l’une par l’autre, & </s> <s xml:id="echoid-s6972" xml:space="preserve">le produit 3360000. </s> <s xml:id="echoid-s6973" xml:space="preserve">par la valeur de a<emph style="sub">3</emph>, c’eſt-<lb/>à-dire par 216 pour avoir 725760000. </s> <s xml:id="echoid-s6974" xml:space="preserve">= dna<emph style="sub">3</emph> qu’il faut diviſer par <lb/>le produit des trois nombres qui expriment la valeur de b, c, m, le-<lb/>quel donnera 2322000. </s> <s xml:id="echoid-s6975" xml:space="preserve">= b, c, m; </s> <s xml:id="echoid-s6976" xml:space="preserve">& </s> <s xml:id="echoid-s6977" xml:space="preserve">le quotient ſera 312, dont il <lb/>faut extraire la racine quarrée qu’on trouvera de 17 pouces, 7 lignes, <lb/>11 points, pour la hauteur verticale de la poutre.</s> <s xml:id="echoid-s6978" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6979" xml:space="preserve">Si la hauteur verticale étoit donnée, & </s> <s xml:id="echoid-s6980" xml:space="preserve">qu’on voulût trouver l’é-<lb/>paiſſeur horiſontale, nommant cette épaiſſeur x; </s> <s xml:id="echoid-s6981" xml:space="preserve">& </s> <s xml:id="echoid-s6982" xml:space="preserve">l’autre c; </s> <s xml:id="echoid-s6983" xml:space="preserve">& </s> <s xml:id="echoid-s6984" xml:space="preserve">tout <lb/>le reſte avec les mêmes lettres, alors la formule ſe changeroit en <lb/>celle-ci {dna<emph style="super">3</emph>/bmcc} = x.</s> <s xml:id="echoid-s6985" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6986" xml:space="preserve">Enfin, ſi les deux dimenſions de l’équariſſage étoient données, & </s> <s xml:id="echoid-s6987" xml:space="preserve"><lb/>qu’on voulût ſçavoir quelle doit être la longueur d’une poutre pour <lb/>caſſer ſous l’éfort du poids n; </s> <s xml:id="echoid-s6988" xml:space="preserve">nommant c, la hauteur verticale, f l’é-<lb/>paiſſeur horiſontale; </s> <s xml:id="echoid-s6989" xml:space="preserve">nous ſervant toûjours du même modele, nous <lb/>aurons encore m, n, : </s> <s xml:id="echoid-s6990" xml:space="preserve">: </s> <s xml:id="echoid-s6991" xml:space="preserve">{a<emph style="sub">3</emph>/b}, {ccf/x} d’où l’on tire cette formule, après a-<lb/>voir dégagé l’inconnuë {bccfm/na<emph style="super">3</emph>} = x.</s> <s xml:id="echoid-s6992" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6993" xml:space="preserve">Comme de toutes les ſituations qu’on peut donner à une piéce de <lb/>bois par rapport à ſa longueur, il n’y en a point où elle ait moins de <lb/>force, que quand elle eſt poſée horiſontalement, il eſt à propos d’e-<lb/>xaminer ce qui arrive quand elle eſt poſée obliquement.</s> <s xml:id="echoid-s6994" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s6995" xml:space="preserve">Si l’on conſidere la poutre AB poſée ſur deux apuis, dont l’un eſt <lb/> <anchor type="note" xlink:label="note-0311-01a" xlink:href="note-0311-01"/> beaucoup plus élevé que l’autre, il eſt conſtant que le poids D qui <lb/>ſeroit ſuſpendu dans le milieu de ſa longueur, n’agiſſant point ſelon <lb/>une direction perpendiculaire au bras de levier, fera d’autant moins <lb/>d’effort pour rompre cette poutre, que l’angle CFG formé par l’o-<lb/>bliquité de la poutre, & </s> <s xml:id="echoid-s6996" xml:space="preserve">la ligne horiſontale FG aprochera davantage <lb/>de valoir un droit, juſques-là que ſi la poutre étoit perpendiculai-<lb/>re à l’horiſon, c’eſt-à-dire que l’angle CFG fût effectivement droit, <pb o="28" file="0312" n="323" rhead="LA SCIENCE DES INGENIEURS,"/> le poids D ne feroit plus aucun effet, parce que ſa direction & </s> <s xml:id="echoid-s6997" xml:space="preserve">celle <lb/>du levier ſe trouveroient dans une même ligne. </s> <s xml:id="echoid-s6998" xml:space="preserve">Mais ſi la poutre eſt <lb/>ſeulement inclinée, comme nous la ſupoſons ici, alors on n’a qu’à <lb/>faire le paralellogramme rectangle EFCH, & </s> <s xml:id="echoid-s6999" xml:space="preserve">l’action du poids ſur la <lb/>poutre poſé horiſontalement ſera à celle du même poids, quand <lb/>cette poutre eſt oblique, comme la diagonale EC eſt au côté EF, ou, <lb/>ce qui revient au même, comme le ſinus de l’angle CFE, eſt au ſinus <lb/>de l’angle FCE: </s> <s xml:id="echoid-s7000" xml:space="preserve">de ſorte que ſi l’on vouloit que cette poutre fût chan-<lb/>gée dans la ſituation oblique de la même façon qu’elle le ſeroit ſi elle <lb/>étoit horiſontale, pour être rompuë dans l’un & </s> <s xml:id="echoid-s7001" xml:space="preserve">l’autre cas, l’on voit <lb/>que quand il faudra dans la ſituation horiſontale un poids exprimé <lb/>par le côté FE, ou par le ſinus de l’angle FCE, celui pour la ſituation <lb/>oblique doit être exprimé par la diagonale EC; </s> <s xml:id="echoid-s7002" xml:space="preserve">par conſequent lorſ-<lb/>que l’angle FCE devient ſi petit, que les deux lignes CE & </s> <s xml:id="echoid-s7003" xml:space="preserve">CA ſe <lb/>trouvent confonduës, ce qui arrive quand la poutre eſt perpendicu-<lb/>laire à l’horiſon, la ligne CE n’étant plus déterminée, le poids que <lb/>peut porter la poutre devient inexprimable.</s> <s xml:id="echoid-s7004" xml:space="preserve"/> </p> <div xml:id="echoid-div324" type="float" level="3" n="4"> <note position="right" xlink:label="note-0311-01" xlink:href="note-0311-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 8.</note> </div> <p> <s xml:id="echoid-s7005" xml:space="preserve">Bullet, en parlant de la charpente dans ſon Architecture pratique, <lb/>dit que la force d’une piéce de bois, qui eſt inclinée, augmente dans <lb/>la raiſon de l’ouverture des angles que cette piéce forme avec la <lb/>ligne horiſontale; </s> <s xml:id="echoid-s7006" xml:space="preserve">&</s> <s xml:id="echoid-s7007" xml:space="preserve">, comme bien des gens ajoûtent foi à tout ce <lb/>que raporte un Auteur qui a quelque réputation, je croi qu’il eſt à <lb/>propos d’expoſer ici mot pour mot le ſentiment de celui que je viens <lb/>de citer, afin de faire enſuite quelques Remarques qui ne ſeront <lb/>peut-être pas inutiles.</s> <s xml:id="echoid-s7008" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7009" xml:space="preserve">A l’égard de la groſſeur des bois, dit-il, l’on peut ſavoir que <lb/>ceux, que l’on employe aux combles, n’ont pas beſoin d’être ſi <lb/>gros par rapport à leur longueur, que ceux qu’on employe aux <lb/>planchers, car ceux-ci ſont poſés de niveau, & </s> <s xml:id="echoid-s7010" xml:space="preserve">ſoufrent beau-<lb/>coup davantage que ceux des combles qui ſont inclinés, & </s> <s xml:id="echoid-s7011" xml:space="preserve">on <lb/>ne doit pas douter qu’une piece de bois poſée de bout, ne por-<lb/>te ſans comparaiſon plus dans une même groſſeur & </s> <s xml:id="echoid-s7012" xml:space="preserve">longueur, <lb/>que ſi elle étoit poſée de niveau; </s> <s xml:id="echoid-s7013" xml:space="preserve">enſorte que ſupoſant qu’une <lb/>piece de bois puiſſe porter, par exemple, 1000 étant poſée de <lb/>niveau, & </s> <s xml:id="echoid-s7014" xml:space="preserve">qu’étant poſé de bout elle porte 3000, ſi on l’in-<lb/>cline d’un demi-angle droit, elle doit porter 2000, & </s> <s xml:id="echoid-s7015" xml:space="preserve">ainſi des <lb/>autres angles plus ou moins inclinés à proportion.</s> </p> <p> <s xml:id="echoid-s7016" xml:space="preserve">Tout le monde penſe avec Bullet, qu’il ne faut pas donner tant <lb/>de groſſeur aux chevrons d’un comble, qu’aux ſolives d’un plan-<lb/>cher, non ſeulement par raport à la ſituation avantageuſe des pre-<lb/>miers, mais auſſi parce que les chevrons ne portent jamais d’autre <pb file="0313" n="324"/> <pb file="0313a" n="325"/> <anchor type="figure" xlink:label="fig-0313a-01a" xlink:href="fig-0313a-01"/> <pb file="0314" n="326"/> <pb o="29" file="0315" n="327" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> poids que celui de la couverture, au lieu que les ſolives, indepen-<lb/>damment des planchers qu’elles ſoutiennent, doivent être auſſi ca-<lb/>pables de porter la peſanteur de tous les corps étrangers dont on <lb/>voudroit les charger, ſelon l’uſage des lieux où elles ſont emplo-<lb/>yées: </s> <s xml:id="echoid-s7017" xml:space="preserve">mais à l’égard du bois poſé obliquement, je ne vois point <lb/>ſur quel fondement il dit, qu’une piece, qui ſeroit inclinée ſous un <lb/>angle de 45. </s> <s xml:id="echoid-s7018" xml:space="preserve">degrés, portera un poids moyen arithmetique, en-<lb/>tre celui qu’elle porteroit ſi elle étoit horiſontale, & </s> <s xml:id="echoid-s7019" xml:space="preserve">entre l’autre <lb/>qu’elle ſoutiendroit ſi elle étoit de bout; </s> <s xml:id="echoid-s7020" xml:space="preserve">car l’on peut bien con-<lb/>noître ce que peut porter cette piece quand elle ſera horiſontale, <lb/>en ſuivant les regles précedentes, mais il n’eſt pas poſſible de dé-<lb/>terminer ce qu’elle portera étant de bout, le poids dans cette der-<lb/>niere ſituation ne pouvant être exprimé, par conſequent il n’eſt <lb/>pas poſſible de trouver des termes moyens: </s> <s xml:id="echoid-s7021" xml:space="preserve">ce n’eſt pas que je <lb/>veuille dire qu’une piece de bois, poſée de bout, ſoit capable de <lb/>porter un fardeau immenſe, je ſais bien que quand elle aura une <lb/>certaine hauteur, elle pourra plier, & </s> <s xml:id="echoid-s7022" xml:space="preserve">même ſe rompre; </s> <s xml:id="echoid-s7023" xml:space="preserve">mais quand <lb/>cela arrive ce n’eſt pas l’effet d’une cauſe ſuſceptible d’aucune regle, <lb/>c’eſt que le poids ne porte pas à plomb, & </s> <s xml:id="echoid-s7024" xml:space="preserve">pouſſe obliquement, ou <lb/>que le bois lui même n’eſt pas bien perpendiculaire, ou ce qui pa-<lb/>roît le plus vraiſemblable encore, c’eſt que le fil peut en être obli-<lb/>que, & </s> <s xml:id="echoid-s7025" xml:space="preserve">par conſequent tende à ſe caſſer du côté le plus foible; <lb/></s> <s xml:id="echoid-s7026" xml:space="preserve">mais comme il ſuffit de ſavoir ce qu’une piece de charpente peut <lb/>porter étant horiſontale, pour juger de ce qu’elle portera quand elle <lb/>ſera miſe dans une ſituation oblique; </s> <s xml:id="echoid-s7027" xml:space="preserve">l’on voit ſelon ce que j’ai <lb/>dit ci-devant, que cette force n’augmente point dans la raiſon de <lb/>l’ouverture des angles, mais ſelon que le ſinus total ſe trouve plus <lb/>grand que les ſinus des complemens des angles, formés par la li-<lb/>gne horiſontale & </s> <s xml:id="echoid-s7028" xml:space="preserve">la piece.</s> <s xml:id="echoid-s7029" xml:space="preserve"/> </p> <div xml:id="echoid-div325" type="float" level="3" n="5"> <figure xlink:label="fig-0313a-01" xlink:href="fig-0313a-01a"> <image file="0313a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0313a-01"/> </figure> </div> <p> <s xml:id="echoid-s7030" xml:space="preserve">Un peu après, cet Auteur continuë en ces termes: </s> <s xml:id="echoid-s7031" xml:space="preserve">„Il y auroit <lb/>„beaucoup de choſes à dire ſur la groſſeur que les bois doivent <lb/>„avoir, par raport à leur longueur & </s> <s xml:id="echoid-s7032" xml:space="preserve">à leur uſage, quand même <lb/>„on les ſupoſeroit generalement tous de même qualité, ce qui ar-<lb/>„rive rarement; </s> <s xml:id="echoid-s7033" xml:space="preserve">cette queſtion ne peut pas être reſoluë par les <lb/>„regles de Geometrie, parce que la connoiſſance de la bonne & </s> <s xml:id="echoid-s7034" xml:space="preserve"><lb/>„mauvaiſe qualité des bois apartient à la Phiſique; </s> <s xml:id="echoid-s7035" xml:space="preserve">ainſi il faut ſe <lb/>„contenter de l’experience, avec laquelle on peut donner quel-<lb/>„ques regles, pour les differentes groſſeurs des poutres, par rap-<lb/>„port à leur longueur, ſupoſant neanmoins que la charge n’en ſoit <lb/>„pas exceſſive, comme quand on fait porter pluſieurs cloiſons & </s> <s xml:id="echoid-s7036" xml:space="preserve"><lb/>„planchers l’un ſur l’autre à une même poutre, ce que j’ai vû en <pb o="30" file="0316" n="328" rhead="LA SCIENCE DES INGENIEURS,"/> „pluſieurs endroits, & </s> <s xml:id="echoid-s7037" xml:space="preserve">ce qu’il faut abſolument éviter. </s> <s xml:id="echoid-s7038" xml:space="preserve">Voici une <lb/>„table pour avoir la groſſeur des poutres ſuivant leur longueur, <lb/>„donnée de 3 pieds en 3 pieds, depuis 12 juſqu’à 42 pieds, laquel-<lb/>„le table a été faite par une regle fondée ſur l’experience, dont <lb/>„chacun pourra ſe ſervir comme il jugera à propos pour ſon utilité.</s> <s xml:id="echoid-s7039" xml:space="preserve"/> </p> <note position="right" xml:space="preserve">Longueur des poutres. # leur largeur. # leur hauteur. <lb/>Une poutre de 12 pieds aura # 10 pouces ſur # 12 pouces. <lb/>15 # 11 # 13 <lb/>18 # 12 # 15 <lb/>21 # 13 # 16 <lb/>24 # 13 {1/2} # 18 <lb/>27 # 15 # 19 <lb/>30 # 16 # 21 <lb/>33 # 17 # 22 <lb/>36 # 18 # 23 <lb/>39 # 19 # 24 <lb/>42 # 20 # 25</note> <p> <s xml:id="echoid-s7040" xml:space="preserve">Il a raiſon de dire, qu’il arrive rarement qu’on rencontre des <lb/>bois de même qualité; </s> <s xml:id="echoid-s7041" xml:space="preserve">mais, c’eſt à tort qu’il croit que les regles <lb/>de la Geometrie ne peuvent être d’aucune utilité, pour proportion-<lb/>ner leur groſſeur à leur longueur, quand on fera abſtraction de la <lb/>difference de leur force naturelle, puiſque je ne crois pas qu’on <lb/>puiſſe y arriver par d’autres voyes, car independamment des ex-<lb/>periences qu’on a rapportées ci-devant, il ſuffira que l’uſage nous <lb/>ait apris que des poutres, des ſolives, des chevrons &</s> <s xml:id="echoid-s7042" xml:space="preserve">c. </s> <s xml:id="echoid-s7043" xml:space="preserve">d’une cer-<lb/>taine longueur & </s> <s xml:id="echoid-s7044" xml:space="preserve">d’une groſſeur déterminée, ayent toûjours bien <lb/>réuſſi, pour qu’on puiſſe après cela trouver les baſes qu’il con-<lb/>vient de donner à ces mêmes pieces, ſi on étoit dans la neceſſité <lb/>de les employer beaucoup plus longues, & </s> <s xml:id="echoid-s7045" xml:space="preserve">alors la pratique ſeule <lb/>ne ſuffit pas pour juger exactement de la groſſeur des bois; </s> <s xml:id="echoid-s7046" xml:space="preserve">c’eſt <lb/>pourquoi je ne vois pas qu’on puiſſe ſe ſervir ſurement de la ta-<lb/>ble qu’il donne, ne rendant aucune raiſon de la maniere dont elle <lb/>a été calculée; </s> <s xml:id="echoid-s7047" xml:space="preserve">j’ai même voulu voir ſi les poutres, qui y ſont ra-<lb/>portées, répondoient tant ſoit peu aux regles qui devoient leur <lb/>convenir, mais je n’ai rien aperceu qui en aprochât. </s> <s xml:id="echoid-s7048" xml:space="preserve">Si j’ai fait <lb/>mention du Livre de Bullet, ce n’a été que pour faire ſentir aux per-<lb/>ſonnes qui veulent s’apliquer à l’Art de bâtir, combien il eſt impor-<lb/>tant qu’ils ayent quelques principes de theorie, qui puiſſent les <lb/>guider dans la pratique.</s> <s xml:id="echoid-s7049" xml:space="preserve"/> </p> <pb o="31" file="0317" n="329" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s7050" xml:space="preserve">Voilà ce que je m’étois propoſé de dire ſur la maniere de con-<lb/>noître la force des bois, qui ſont en uſage dans les bâtimens: </s> <s xml:id="echoid-s7051" xml:space="preserve">j’a-<lb/>vois fort envie de ne pas m’en tenir-là, & </s> <s xml:id="echoid-s7052" xml:space="preserve">de faire d’autres apli-<lb/>cations des principes de la mécanique à la charpente, pour montrer <lb/>quelle eſt la diſpoſition la plus avantageuſe qu’il convient de don-<lb/>ner à l’aſſemblage des pieces de toute ſorte d’ouvrages en général, <lb/>pour être capables de reſiſter le plus qu’il eſt poſſible, aux pouſſées <lb/>qu’ils auroient à ſoûtenir, avec un certain nombre de ſolives détermi-<lb/>né, neceſſaire ſeulement pour l’éxecution de ce que l’on a en vuë, <lb/>car on ne peut douter que dans les fermes qui ſoûtiennent les com-<lb/>bles, celles qui ſont employées pour les jettées qui ſe font dans la <lb/>mer, les chevalets des ponts, les portes des écluſes &</s> <s xml:id="echoid-s7053" xml:space="preserve">c. </s> <s xml:id="echoid-s7054" xml:space="preserve">il n’y ait <lb/>des puiſſances qui agiſſent & </s> <s xml:id="echoid-s7055" xml:space="preserve">qui reſiſtent ſelon certaine direction, <lb/>& </s> <s xml:id="echoid-s7056" xml:space="preserve">par conſequent des leviers de differente eſpece, & </s> <s xml:id="echoid-s7057" xml:space="preserve">que tout cela <lb/>ne faſſe un mécaniſme, dont la connoiſſance ne peut être que très <lb/>utile, que j’aurois volontiers developé, ſi je m’étois trouvé plus de <lb/>loiſir que je n’en ai preſentement; </s> <s xml:id="echoid-s7058" xml:space="preserve">car ayant commencé à écrire <lb/>quelques chapitres ſur ce ſujet, je me ſuis aperçu que pour les trai-<lb/>ter comme il faut, je ſerois obligé d’embraſſer un ouvrage qui de-<lb/>viendroit fort étendu, mais que je me propoſe pourtant de ré-<lb/>prendre dans le ſecond Volume.</s> <s xml:id="echoid-s7059" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div327" type="section" level="2" n="113"> <head xml:id="echoid-head259" xml:space="preserve">CHAPITRE QUATRIE’ME.</head> <head xml:id="echoid-head260" style="it" xml:space="preserve">Des bonnes & mauvaiſes Qualités du Fer.</head> <p> <s xml:id="echoid-s7060" xml:space="preserve">LE grand uſage que l’on fait du fer dans les travaux du genie <lb/>& </s> <s xml:id="echoid-s7061" xml:space="preserve">de l’artillerie, en rend la connoiſſance ſi neceſſaire, que <lb/>j’ai crû ne pouvoir me diſpenſer de raporter ici toutes les Obſer-<lb/>vations qui pouvoient contribuer à en faire un bon choix: </s> <s xml:id="echoid-s7062" xml:space="preserve">pour <lb/>cela, j’ai eu recours à ce que l’experience a apris à ceux qui travail-<lb/>lent continuellement dans les Forges des Arſenaux du Roy; </s> <s xml:id="echoid-s7063" xml:space="preserve">& </s> <s xml:id="echoid-s7064" xml:space="preserve"><lb/>comme je ne connois point d’Auteur qui traite mieux cette matie-<lb/>re que Monſieur Felibien, dans ſes Memoires d’Architecture, j’ai <lb/>profité auſſi des Inſtructions qu’il donne.</s> <s xml:id="echoid-s7065" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7066" xml:space="preserve">Pour juger de la qualité du fer, il faut ſavoir de quelle Forge il <lb/>vient, ſi la mine d’où il eſt tiré eſt douce ou caſſante; </s> <s xml:id="echoid-s7067" xml:space="preserve">& </s> <s xml:id="echoid-s7068" xml:space="preserve">pour con-<lb/>noître ces mines, voici ce que l’on a remarqué ſur celles qui four-<lb/>niſſent du fer en France.</s> <s xml:id="echoid-s7069" xml:space="preserve"/> </p> <pb o="32" file="0318" n="330" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s7070" xml:space="preserve">Le meilleur fer, que nous ayons, eſt celui qui ſe tire des mines <lb/>de Berry; </s> <s xml:id="echoid-s7071" xml:space="preserve">il y a quelques années que l’on en a travaillé une grande <lb/>quantité à l’Arſenal de la Ferre; </s> <s xml:id="echoid-s7072" xml:space="preserve">les ouvriers l’ont trouvé ſi excel-<lb/>lent, qu’ils ne pouvoient lui donner aſſez d’éloge. </s> <s xml:id="echoid-s7073" xml:space="preserve">Le fer de <lb/>Bourgogne eſt auſſi fort bon, cette Province en fournit pour la con-<lb/>ſtruction des Vaiſſeaux & </s> <s xml:id="echoid-s7074" xml:space="preserve">Galeres qui ſe font à Toulon & </s> <s xml:id="echoid-s7075" xml:space="preserve">à Mar-<lb/>ſeille; </s> <s xml:id="echoid-s7076" xml:space="preserve">on le tire particulierement des Forges de Peſmes & </s> <s xml:id="echoid-s7077" xml:space="preserve">de Mo-<lb/>rambert, parce qu’il eſt fort doux & </s> <s xml:id="echoid-s7078" xml:space="preserve">aiſé à employer.</s> <s xml:id="echoid-s7079" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7080" xml:space="preserve">Le fer de Senonge & </s> <s xml:id="echoid-s7081" xml:space="preserve">celui de Vibray, proche Monmiral au Mans, <lb/>eſt aſſez eſtimé, parce qu’il ſe forge bien, étant doux & </s> <s xml:id="echoid-s7082" xml:space="preserve">pliant.</s> <s xml:id="echoid-s7083" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7084" xml:space="preserve">L’on ne fait pas grand cas du fer de Normandie, non plus que de <lb/>celui de Champagne & </s> <s xml:id="echoid-s7085" xml:space="preserve">de Thierrage, parce qu’il eſt fort caſſant & </s> <s xml:id="echoid-s7086" xml:space="preserve"><lb/>d’une très mauvaiſe qualité.</s> <s xml:id="echoid-s7087" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7088" xml:space="preserve">Le fer de Roche eſt bon, s’employant bien en toute ſorte d’ou-<lb/>vrage, de même que celui qui vient des mines de Nivernois; </s> <s xml:id="echoid-s7089" xml:space="preserve">ce der-<lb/>nier étant fort doux, propre à faire des épées, & </s> <s xml:id="echoid-s7090" xml:space="preserve">des canons de fu-<lb/>ſils: </s> <s xml:id="echoid-s7091" xml:space="preserve">il eſt même d’une qualité qui aproche fort de l’acier.</s> <s xml:id="echoid-s7092" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7093" xml:space="preserve">Celui qu’on tire de Signy le petit eſt dur & </s> <s xml:id="echoid-s7094" xml:space="preserve">caſſant, mal aiſé à <lb/>forger, le grain en eſt gros & </s> <s xml:id="echoid-s7095" xml:space="preserve">clair, par conſequent d’une mauvaiſe <lb/>qualité, auſſi ne l’employe-t-on guere que pour les bombes & </s> <s xml:id="echoid-s7096" xml:space="preserve">les <lb/>boulets.</s> <s xml:id="echoid-s7097" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7098" xml:space="preserve">Le fer d’Eſpagne eſt très doux, de maniere qu’on le forge à <lb/>froid comme l’argent: </s> <s xml:id="echoid-s7099" xml:space="preserve">il y a des Forges entre St. </s> <s xml:id="echoid-s7100" xml:space="preserve">Sebaſtien & </s> <s xml:id="echoid-s7101" xml:space="preserve">le <lb/>Paſſage, dont le fer a cette qualité.</s> <s xml:id="echoid-s7102" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7103" xml:space="preserve">J’ai vû d’habiles gens, partagés ſur le fer de Suede &</s> <s xml:id="echoid-s7104" xml:space="preserve">d’Allemagne, <lb/>les uns en faiſant beaucoup de cas, & </s> <s xml:id="echoid-s7105" xml:space="preserve">les autres ne l’eſtimant gue-<lb/>re; </s> <s xml:id="echoid-s7106" xml:space="preserve">au reſte, il eſt fort bon, quand il eſt corroyé avec d’autre fer <lb/>pour des outils tranchans.</s> <s xml:id="echoid-s7107" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7108" xml:space="preserve">J’ai dit que le fer de Berry étoit de très bonne qualité; </s> <s xml:id="echoid-s7109" xml:space="preserve">mais il eſt <lb/>à propos d’obſerver qu’il s’en trouve de deux eſpeces, l’un & </s> <s xml:id="echoid-s7110" xml:space="preserve"><lb/>l’autre ſe debitent en barre, toute la difference eſt, que l’un eſt de <lb/>fer battu, & </s> <s xml:id="echoid-s7111" xml:space="preserve">l’autre ſe tire comme le Vitrier tire le plomb, & </s> <s xml:id="echoid-s7112" xml:space="preserve">par <lb/>là on le fait auſſi mince & </s> <s xml:id="echoid-s7113" xml:space="preserve">auſſi large que l’on veut; </s> <s xml:id="echoid-s7114" xml:space="preserve">mais ce qu’il <lb/>y a de particulier, c’eſt que celui qui eſt ainſi tiré eſt d’une qua-<lb/>lité incomparablement meilleure que l’autre qui eſt battu, étant <lb/>plus nerveux: </s> <s xml:id="echoid-s7115" xml:space="preserve">l’on n’y voit preſque point de grain, & </s> <s xml:id="echoid-s7116" xml:space="preserve">on a de la <lb/>peine à le caſſer à froid; </s> <s xml:id="echoid-s7117" xml:space="preserve">aparamment que le rouleau contribuë <lb/>beaucoup à lui donner cette qualité.</s> <s xml:id="echoid-s7118" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7119" xml:space="preserve">Comme il ſe rencontre du fer bon & </s> <s xml:id="echoid-s7120" xml:space="preserve">mauvais, quoi qu’il vien-<lb/>ne de la même Forge, & </s> <s xml:id="echoid-s7121" xml:space="preserve">quelquefois de la même Gueuſe, il faut <lb/>pour en être plus ſur, en prendre une barre: </s> <s xml:id="echoid-s7122" xml:space="preserve">ſi l’on voit qu’il y ait <pb o="33" file="0319" n="331" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> de petites veines noires, qui s’étendent au long, & </s> <s xml:id="echoid-s7123" xml:space="preserve">qu’on n’y aper-<lb/>çoive point de gerſures, ou de coupures qui aillent en travers, & </s> <s xml:id="echoid-s7124" xml:space="preserve"><lb/>que cette barre ſoit pliante ſous le marteau, c’eſt une marque que <lb/>le fer eſt bon; </s> <s xml:id="echoid-s7125" xml:space="preserve">au lieu que s’il y avoit des gerſures, & </s> <s xml:id="echoid-s7126" xml:space="preserve">que ia barre <lb/>fût roide, c’eſt une preuve évidente que le fer eſt Rouverain, c’eſt-<lb/>à-dire caſſant à chaud, & </s> <s xml:id="echoid-s7127" xml:space="preserve">qu’il eſt difficile à forger.</s> <s xml:id="echoid-s7128" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7129" xml:space="preserve">On connoîtra encore ſi le fer eſt doux, à la couleur qu’il aura en <lb/>dedans après l’avoir caſſé, car s’il eſt noir, c’eſt ſigne qu’il eſt bon, <lb/>& </s> <s xml:id="echoid-s7130" xml:space="preserve">malleable à froid & </s> <s xml:id="echoid-s7131" xml:space="preserve">à la lime; </s> <s xml:id="echoid-s7132" xml:space="preserve">mais auſſi il eſt ſujet à être cen-<lb/>dreux, c’eſt-à-dire qu’il ne devient pas plus clair après qu’il eſt <lb/>poli, principalement s’il s’y rencontre des taches griſes comme de <lb/>la cendre, car c’eſt ce qui le rend difficile à polir, & </s> <s xml:id="echoid-s7133" xml:space="preserve">à mettre en <lb/>bon luſtre, ce qui n’arive pas à toutes les barres, mais à la plû-<lb/>part; </s> <s xml:id="echoid-s7134" xml:space="preserve">auſſi cette ſorte de fer eſt moins ſujette à ſe roüiller, par-<lb/>ce qu’il tient un peu de la nature du Plomb.</s> <s xml:id="echoid-s7135" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7136" xml:space="preserve">Il y a d’autres barres dont le fer, à la caſſe, paroît gris, noir, & </s> <s xml:id="echoid-s7137" xml:space="preserve"><lb/>tirant ſur le blanc; </s> <s xml:id="echoid-s7138" xml:space="preserve">il eſt beaucoup plus dur & </s> <s xml:id="echoid-s7139" xml:space="preserve">plus roide que le <lb/>précédent lors qu’on le plie: </s> <s xml:id="echoid-s7140" xml:space="preserve">il eſt très propre à être employé aux <lb/>gros ouvrages dans les bâtimens; </s> <s xml:id="echoid-s7141" xml:space="preserve">mais, pour la lime, il eſt mal ai-<lb/>ſé, à cauſe qu’il s’y rencontre des grains qu’on ne peut emporter <lb/>facilement.</s> <s xml:id="echoid-s7142" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7143" xml:space="preserve">Celui qui, étant caſſé, a le grain mêlé de blanc, de gris, ou de <lb/>noir, eſt ſouvent le meilleur, ſoit pour la forge ou la lime, & </s> <s xml:id="echoid-s7144" xml:space="preserve"><lb/>pour ſe bien polir.</s> <s xml:id="echoid-s7145" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7146" xml:space="preserve">Il y a d’autres barres, qui ont le grain petit comme de l’acier, & </s> <s xml:id="echoid-s7147" xml:space="preserve"><lb/>dont le fer eſt pliant à froid, il eſt mal aiſé à limer, & </s> <s xml:id="echoid-s7148" xml:space="preserve">greſille lors <lb/>qu’il commence à être chaud, de ſorte qu’il eſt difficile à em-<lb/>ployer, à la forge & </s> <s xml:id="echoid-s7149" xml:space="preserve">à la lime, attendu qu’il ne ſe ſoude pas faci-<lb/>lement, & </s> <s xml:id="echoid-s7150" xml:space="preserve">qu’à la lime il a des grains; </s> <s xml:id="echoid-s7151" xml:space="preserve">il eſt bon pour ceux qui <lb/>font de gros ouvrages.</s> <s xml:id="echoid-s7152" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7153" xml:space="preserve">Il y en a encore d’autres, dont le grain eſt gros & </s> <s xml:id="echoid-s7154" xml:space="preserve">clair à la caſſe, <lb/>comme de l’étain de glace: </s> <s xml:id="echoid-s7155" xml:space="preserve">ce fer eſt de mauvaiſe qualité, car il <lb/>eſt caſſant à froid & </s> <s xml:id="echoid-s7156" xml:space="preserve">tendre au feu, ne pouvant ſouffrir une gran-<lb/>de chaleur ſans ſe brûler, parce qu’il eſt fort poreux, aiſé à ſe <lb/>rouiller & </s> <s xml:id="echoid-s7157" xml:space="preserve">à ſe manger.</s> <s xml:id="echoid-s7158" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7159" xml:space="preserve">Le fer, qu’on apelle Rouverain, ſe connoit; </s> <s xml:id="echoid-s7160" xml:space="preserve">comme je viens de di-<lb/>re, lors qu’il y a des gerſures ou des coupures, qui vont au travers <lb/>des barres; </s> <s xml:id="echoid-s7161" xml:space="preserve">il eſt d’ordinaire pliant & </s> <s xml:id="echoid-s7162" xml:space="preserve">malleable à froid: </s> <s xml:id="echoid-s7163" xml:space="preserve">ſi en le <lb/>forgeant il ſent le ſoufre, & </s> <s xml:id="echoid-s7164" xml:space="preserve">qu’en le frapant il en ſorte de petites <lb/>étincelles, c’eſt une marque qu’il eſt caſſant à chaud; </s> <s xml:id="echoid-s7165" xml:space="preserve">auſſi lors <lb/>qu’il vient en ſa mauvaiſe couleur, qui eſt d’ordinaire un peu plus <pb o="34" file="0320" n="332" rhead="LA SCIENCE DES INGENIEURS,"/> blanche que couleur de ceriſe, il caſſe quelquefois tout au travers <lb/>de la piece; </s> <s xml:id="echoid-s7166" xml:space="preserve">ſi on le frape, & </s> <s xml:id="echoid-s7167" xml:space="preserve">qu’on le ploye, il deviendra tout <lb/>pailleux.</s> <s xml:id="echoid-s7168" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7169" xml:space="preserve">Les ouvriers, & </s> <s xml:id="echoid-s7170" xml:space="preserve">ceux qui ont accoûtumé de faire travailler, con-<lb/>noiſſent bien la qualité du fer en le forgeant, car s’il eſt doux ſous <lb/>le marteau, il ſera caſſant à froid, au lieu que s’il eſt ferme, c’eſt <lb/>ſigne qu’il ſera ployant à froid.</s> <s xml:id="echoid-s7171" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7172" xml:space="preserve">Comme il ſe rencontre des occaſions, où il eſt neceſſaire de <lb/>ſavoir les differentes eſpeces de fer que l’on tire des Forges, voi-<lb/>ci les dimenſions de celui qui ſe debite le plus communement chez <lb/>les Marchands: </s> <s xml:id="echoid-s7173" xml:space="preserve">il ne s’en rencontre guere d’autres, à moins qu’il <lb/>ne ſoit de commande.</s> <s xml:id="echoid-s7174" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7175" xml:space="preserve">Le fer plat a 9 à dix pieds de long, & </s> <s xml:id="echoid-s7176" xml:space="preserve">quelquefois plus, ſur 2 <lb/>pouces & </s> <s xml:id="echoid-s7177" xml:space="preserve">demi de large, & </s> <s xml:id="echoid-s7178" xml:space="preserve">4 lignes où environ d’épaiſleur: </s> <s xml:id="echoid-s7179" xml:space="preserve">il s’en <lb/>trouve même de 12 & </s> <s xml:id="echoid-s7180" xml:space="preserve">13 pieds de long, ſur 3 pouces & </s> <s xml:id="echoid-s7181" xml:space="preserve">demi <lb/>& </s> <s xml:id="echoid-s7182" xml:space="preserve">4 pouces de large.</s> <s xml:id="echoid-s7183" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7184" xml:space="preserve">Le fer, qu’on nomme quarré, eſt en barre de diverſe longueur, <lb/>& </s> <s xml:id="echoid-s7185" xml:space="preserve">a depuis un juſqu’à 2 pouces ou environ en quarré.</s> <s xml:id="echoid-s7186" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7187" xml:space="preserve">Le quarré batard a 9 pieds de long, & </s> <s xml:id="echoid-s7188" xml:space="preserve">16 à 18 lignes en quarré.</s> <s xml:id="echoid-s7189" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7190" xml:space="preserve">Le fer Cornette a 8 ou 9 pieds de long, 3 pouces de large, & </s> <s xml:id="echoid-s7191" xml:space="preserve"><lb/>4 à 5 lignes d’épaiſſeur.</s> <s xml:id="echoid-s7192" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7193" xml:space="preserve">Le fer Rond à 6 à 7 pieds de long, ſur 6 lignes de diamétre.</s> <s xml:id="echoid-s7194" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7195" xml:space="preserve">Le fer de Carillon eſt un petit fer qui n’a que 8 à 9 lignes de <lb/>groſſeur.</s> <s xml:id="echoid-s7196" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7197" xml:space="preserve">Celui de Courçon eſt par gros morceaux de 2, 3 & </s> <s xml:id="echoid-s7198" xml:space="preserve">4 pieds de <lb/>long.</s> <s xml:id="echoid-s7199" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7200" xml:space="preserve">La Taule eſt en feuilles, & </s> <s xml:id="echoid-s7201" xml:space="preserve">de pluſieurs largeurs & </s> <s xml:id="echoid-s7202" xml:space="preserve">hauteurs.</s> <s xml:id="echoid-s7203" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7204" xml:space="preserve">Il y a outre cela le petit fer en botte, qui ſert pour faire les ver-<lb/>gettes des vitres & </s> <s xml:id="echoid-s7205" xml:space="preserve">autres ouvrages.</s> <s xml:id="echoid-s7206" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7207" xml:space="preserve">Je ne dis rien du fer coulé, ou qu’il faut forger exprès pour des <lb/>machines, parce que les aplications qu’on en feroit ici ſeroient <lb/>hors de propos.</s> <s xml:id="echoid-s7208" xml:space="preserve"/> </p> <pb o="35" file="0321" n="333" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> </div> <div xml:id="echoid-div328" type="section" level="2" n="114"> <head xml:id="echoid-head261" xml:space="preserve">CHAPITRE CINQUIE’ME.</head> <head xml:id="echoid-head262" style="it" xml:space="preserve">Des Portes que l’on fait aux Villes de Guerre.</head> <p> <s xml:id="echoid-s7209" xml:space="preserve"><emph style="sc">AVant</emph> qu’on ne fortifiât les Places comme on le fait depuis <lb/>un ſiécle, on avoit recours à mille inventions pour garentir <lb/>les Portes des ſurpriſes: </s> <s xml:id="echoid-s7210" xml:space="preserve">on pratiquoit à droit & </s> <s xml:id="echoid-s7211" xml:space="preserve">à gauche du paſ-<lb/>ſage des eſpeces de Corridors ou Places d’Armes garnis de Cre-<lb/>neaux qui ſervoient à paſſer par les armes ceux qui après avoir en-<lb/>foncé la premiere Porte avec le Petard ou le Canon ſe trouvoient <lb/>arrêtés par la herſe ou autre barriere; </s> <s xml:id="echoid-s7212" xml:space="preserve">&</s> <s xml:id="echoid-s7213" xml:space="preserve">, afin d’enfiler & </s> <s xml:id="echoid-s7214" xml:space="preserve">voir de <lb/>revers, on faiſoit quelquefois le paſſage de biais, ce qui le rendoit <lb/>ſi obſcur à cauſe que l’entrée & </s> <s xml:id="echoid-s7215" xml:space="preserve">la ſortie n’étoient point directe-<lb/>ment opoſées, qu’il reſſembloit à un coupe-gorge. </s> <s xml:id="echoid-s7216" xml:space="preserve">Aujourd’hui <lb/>que la force des Places conſiſte dans les Ouvrages détachés, on fait <lb/>les Portes beaucoup plus ſimples. </s> <s xml:id="echoid-s7217" xml:space="preserve">On ſe contente de les couvrir <lb/>par une demi-Lune lorſquelles ſont conſtruites dans le milieu des <lb/>courtines & </s> <s xml:id="echoid-s7218" xml:space="preserve">d’en deffendre l’entrée par les flancs des Baſtions <lb/>voiſins; </s> <s xml:id="echoid-s7219" xml:space="preserve">&</s> <s xml:id="echoid-s7220" xml:space="preserve">, pour en juger d’un coup d’œil, il ſuffira de conſiderer <lb/>les Planches 13 & </s> <s xml:id="echoid-s7221" xml:space="preserve">14, qui comprennent les Plans, Profils, & </s> <s xml:id="echoid-s7222" xml:space="preserve">Ele-<lb/> <anchor type="note" xlink:label="note-0321-01a" xlink:href="note-0321-01"/> vations d’une Porte avec toutes les dimenſions de ſes parties, que <lb/>l’on a cottées exprès pour n’avoir pas recours à l’échelle: </s> <s xml:id="echoid-s7223" xml:space="preserve">ainſi, ſans <lb/>entrer dans un grand détail, je dirai ſeulement, que les ouvertures des <lb/>Portes entre les piés-droits doivent avoir 9 à 10 pieds ſur 13 à 14 <lb/>de hauteur; </s> <s xml:id="echoid-s7224" xml:space="preserve">que le paſſage eſt accompagné de Pilaſtres de diſtance <lb/>en diſtance, pour porter les arcs-doubleaux de la Voûte; </s> <s xml:id="echoid-s7225" xml:space="preserve">que ces <lb/>Pilaſtres ont 2 pieds & </s> <s xml:id="echoid-s7226" xml:space="preserve">demi de largeur ſur 4 ou 5 pouces de ſaillie; <lb/></s> <s xml:id="echoid-s7227" xml:space="preserve">qu’on pratique entre deux des niches ménagées dans I’épaiſſeur des <lb/>piés-droits, qui ſervent à retirer les gens de pied, quand le paſſage <lb/>eſt embaraſſé par quelque Voiture. </s> <s xml:id="echoid-s7228" xml:space="preserve">A l’égard de l’épaiſſeur des piés-<lb/>droits, je croi qu’il eſt inutile d’en parler, puiſque ſi l’on eſt bien <lb/>prévenu de ce qui a été enſeigné ſur la pouſſée des Terres & </s> <s xml:id="echoid-s7229" xml:space="preserve">celle <lb/>des Voûtes, l’on pourra ſans difficulté trouver l’épaiſſeur qu’il faut <lb/>leur donner, ſelon la grandeur & </s> <s xml:id="echoid-s7230" xml:space="preserve">la figure de la Voûte; </s> <s xml:id="echoid-s7231" xml:space="preserve">& </s> <s xml:id="echoid-s7232" xml:space="preserve">ayant dit <lb/>auſſi, dans le troiſiéme Livre, les précautions qu’il falloit prendre <lb/>pour garentir les Voûtes des injures du tems, on ne doit point igno-<lb/>rer non plus ce qu’il faudra faire ſi une partie du paſſage n’étoit point <lb/>couverte par un Bâtiment qui regnât d’un bout à l’autre, comme <pb o="36" file="0322" n="334" rhead="LA SCIENCE DES INGENIEURS,"/> cela ſe rencontre ordinairement, ainſi qu’on le peut voir dans le <lb/>Profil de la Porte dont nous parlons, où l’on remarquera que le paſ-<lb/>ſage du Rempart au-deſſus de la Voûte n’eſt pas entierement cou-<lb/>vert, n’y ayant que deux petits bâtimens, dont l’un fait face à la <lb/>Campagne, & </s> <s xml:id="echoid-s7233" xml:space="preserve">l’autre à la Ville: </s> <s xml:id="echoid-s7234" xml:space="preserve">le premier ſert pour loger l’orgue, <lb/>qui eſt une Porte à couliſſe qui ſe léve & </s> <s xml:id="echoid-s7235" xml:space="preserve">ſe baiſſe perpendiculai-<lb/>rement par le moyen d’un tour qu’on lâche de façon que l’orgue <lb/>peut tomber tout d’un coup; </s> <s xml:id="echoid-s7236" xml:space="preserve">cette Porte ſert à couper le paſſage <lb/>aux Ennemis en cas de quelque ſurpriſe en tems de Siége, ſile Pont-<lb/>Levis venoit à être rompu par le Canon: </s> <s xml:id="echoid-s7237" xml:space="preserve">l’autre bâtiment, qui eſt <lb/>du côté de la Ville, eſt deſtiné à loger un Capitaine des Portes ou <lb/>un Ayde-Major de la Place.</s> <s xml:id="echoid-s7238" xml:space="preserve"/> </p> <div xml:id="echoid-div328" type="float" level="3" n="1"> <note position="right" xlink:label="note-0321-01" xlink:href="note-0321-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>13 & 14.</note> </div> <p> <s xml:id="echoid-s7239" xml:space="preserve">Pour veiller à la fûreté des Portes, l’on fait deux Corps de Garde, <lb/>l’un pour l’Officier, & </s> <s xml:id="echoid-s7240" xml:space="preserve">l’autre pour les Soldats, & </s> <s xml:id="echoid-s7241" xml:space="preserve">on pratique entre <lb/>deux un veſtibule au-deſſus duquel eſt le bâtiment dont nous venons <lb/>de parler, & </s> <s xml:id="echoid-s7242" xml:space="preserve">à côté de ces corps de Gardes l’on fait deux Eſcaliers <lb/>de Pierre de Taille pour monter au Rempart.</s> <s xml:id="echoid-s7243" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7244" xml:space="preserve">Le Corps de Garde de l’Officier ne devant pas être à beaucoup <lb/>près ſi grand que celui des Soldats, on conſtruit à côté une Priſon; <lb/></s> <s xml:id="echoid-s7245" xml:space="preserve">& </s> <s xml:id="echoid-s7246" xml:space="preserve">alors la façade des deux Corps de Garde ſe trouve de même gran-<lb/>deur, ce qui offre avec celle du bâtiment ſuperieur une décoration <lb/>aſſés belle, comme on le peut voir ſur la Planche 13. </s> <s xml:id="echoid-s7247" xml:space="preserve">& </s> <s xml:id="echoid-s7248" xml:space="preserve">même ſur <lb/>la 15. </s> <s xml:id="echoid-s7249" xml:space="preserve">qui comprend encore une autre Porte de Ville à peu-près <lb/>ſemblable à la précédente. </s> <s xml:id="echoid-s7250" xml:space="preserve">J’ai raporté ces deux Portes exprès, afin <lb/>de donner quelque exemple de la maniere dont il faut détailler les <lb/>deſſeins que répreſentent les Plans, Profils, & </s> <s xml:id="echoid-s7251" xml:space="preserve">Elevations des projets <lb/>ou des réparations des Edifices dont les Ingenieurs ſont chargés; </s> <s xml:id="echoid-s7252" xml:space="preserve"><lb/>puiſque c’eſt en copiant de ſemblables morceaux, que les jeunes <lb/>gens peuvent ſe mettre dans l’habitude d’en faire d’autres. </s> <s xml:id="echoid-s7253" xml:space="preserve">Pour <lb/>avoir une plus grande intelligence dela Conſtruction de la premiere <lb/>Porte, il faut lire l’Article qui répond à la 30<emph style="sub">e</emph> page du ſixiéme Livre.</s> <s xml:id="echoid-s7254" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7255" xml:space="preserve">Comme, dans les Places conſidérables, il y a pluſieurs poſtes de-<lb/>puis la Porte juſqu’à la derniere barriere, on y fait des Corps de <lb/>Gardes, qui ſont à peu-près ſemblables à celui qui eſt ſur la Planche <lb/>15, dont il ſuffit de conſiderer le Plan & </s> <s xml:id="echoid-s7256" xml:space="preserve">l’Elevation, pour juger de <lb/>ſa diſtribution. </s> <s xml:id="echoid-s7257" xml:space="preserve">On remarquera ſeulement, qu’on a pratiqué un Poële <lb/>à la façon d’Allemagne, qui, ſe trouvant entre le Corps de Garde <lb/>de l’Officier, & </s> <s xml:id="echoid-s7258" xml:space="preserve">celui des Soldats, peut les échauffer tous deux.</s> <s xml:id="echoid-s7259" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7260" xml:space="preserve">L’on fait des façades d’Architecture en dehors des Portes pour <lb/>les orner, au ſujet deſquelles je ne dirai par grand choſe préſente-<lb/>ment, parce que les proportions de leurs ornemens dépendent des <pb file="0323" n="335"/> <pb file="0323a" n="336"/> <anchor type="figure" xlink:label="fig-0323a-01a" xlink:href="fig-0323a-01"/> <pb file="0324" n="337"/> <pb file="0325" n="338"/> <pb file="0325a" n="339"/> <anchor type="figure" xlink:label="fig-0325a-01a" xlink:href="fig-0325a-01"/> <pb file="0326" n="340"/> <pb o="37" file="0327" n="341" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> régles que l’on trouvera dans le cinquiéme Livre: </s> <s xml:id="echoid-s7261" xml:space="preserve">celle qui eſt ſur <lb/>la Planche 13. </s> <s xml:id="echoid-s7262" xml:space="preserve">me plairoit aſſés; </s> <s xml:id="echoid-s7263" xml:space="preserve">elle a quelque choſe de grand, quoi-<lb/>que ſimple & </s> <s xml:id="echoid-s7264" xml:space="preserve">ruſtique, & </s> <s xml:id="echoid-s7265" xml:space="preserve">n’eſt que d’une dépenſe médiocre. </s> <s xml:id="echoid-s7266" xml:space="preserve">Celle <lb/>de la Planche 15. </s> <s xml:id="echoid-s7267" xml:space="preserve">n’eſt pas ſi belle, auſſi la ſupoſe-t-on faite pour <lb/>un endroit où on ne jugeroit pas à propos de donner dans le ma-<lb/>gnifique. </s> <s xml:id="echoid-s7268" xml:space="preserve">On en peut voir encore quatre autres beaucoup plus éle-<lb/>gantes ſur les Planches 16 & </s> <s xml:id="echoid-s7269" xml:space="preserve">17.</s> <s xml:id="echoid-s7270" xml:space="preserve">, que je donne à deſſein de mon-<lb/> <anchor type="note" xlink:label="note-0327-01a" xlink:href="note-0327-01"/> trer que la belle décoration n’eſt pas incompatible avec les Forti-<lb/>fications; </s> <s xml:id="echoid-s7271" xml:space="preserve">elles ont eû l’aprobation des plus habiles Architectes: <lb/></s> <s xml:id="echoid-s7272" xml:space="preserve">on les trouvera peut-être trop riches, pour être employées à des <lb/>Villes de Guerre; </s> <s xml:id="echoid-s7273" xml:space="preserve">mais, je pourrois dire que la dépenſe n’a ja-<lb/>mais effrayé nos Roys, puiſqu’à Lille, & </s> <s xml:id="echoid-s7274" xml:space="preserve">à Maubeuge, & </s> <s xml:id="echoid-s7275" xml:space="preserve">à pluſieurs <lb/>autres Places, on y voit des Portes qui ſont au moins auſſi ma-<lb/>gnifiques que celles-ci.</s> <s xml:id="echoid-s7276" xml:space="preserve"/> </p> <div xml:id="echoid-div329" type="float" level="3" n="2"> <figure xlink:label="fig-0323a-01" xlink:href="fig-0323a-01a"> <image file="0323a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0323a-01"/> </figure> <figure xlink:label="fig-0325a-01" xlink:href="fig-0325a-01a"> <image file="0325a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0325a-01"/> </figure> <note position="right" xlink:label="note-0327-01" xlink:href="note-0327-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>16 & 17.</note> </div> <p> <s xml:id="echoid-s7277" xml:space="preserve">Les Portes ſe ferment ordinairement par un Pont qu’on peut <lb/>lever & </s> <s xml:id="echoid-s7278" xml:space="preserve">baiſſer de pluſieurs manieres: </s> <s xml:id="echoid-s7279" xml:space="preserve">la plus ancienne, & </s> <s xml:id="echoid-s7280" xml:space="preserve">qui eſt <lb/>encore en uſage en bien des endroits, eſt celle qui ſe fait avec une <lb/>baſcule qui eſt compoſée de pluſieurs piéces de Charpente, & </s> <s xml:id="echoid-s7281" xml:space="preserve">prin-<lb/>cipalement de deux flêches, aux extrêmités deſquelles il y a des <lb/>chaînes qui ſont attachées au tablier du Pont pour lui donner le <lb/>mouvement, comme on le peut voir dans la deuxiéme Figure de <lb/>la Planche 18. </s> <s xml:id="echoid-s7282" xml:space="preserve">On n’en fait plus ainſi aux Places neuves, parce que <lb/> <anchor type="note" xlink:label="note-0327-02a" xlink:href="note-0327-02"/> les flêches font voir de loin quand le Pont eſt levé ou baiſſé, & </s> <s xml:id="echoid-s7283" xml:space="preserve">que <lb/>le Canon de l’ennemi peut facilement les rompre, par conſéquent <lb/>faire baiſſer le Pont ſans que ceux de la Place puiſſent l’empêcher: <lb/></s> <s xml:id="echoid-s7284" xml:space="preserve">un autre défaut, c’eſt qu’on eſt obligé de couper les plus beaux <lb/>ornemens du frontiſpice de la Porte pour loger lesflêches, comme <lb/>on le peut remarquer à la façade dont nous parlons.</s> <s xml:id="echoid-s7285" xml:space="preserve"/> </p> <div xml:id="echoid-div330" type="float" level="3" n="3"> <note position="right" xlink:label="note-0327-02" xlink:href="note-0327-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>18. <lb/><emph style="sc">Fig</emph>. 2.</note> </div> <p> <s xml:id="echoid-s7286" xml:space="preserve">L’on s’eſt ſervidans quelqu’endroit d’une autre ſorte de Pont-Le-<lb/>vis, dont les flêches ne paroiſſent point en dehors de la Place: </s> <s xml:id="echoid-s7287" xml:space="preserve">tel <lb/>eſt celui qui eſt répreſenté dans le premier Profil, qui montre que la <lb/>flêche BD, tourne ſur ſes tourillons à l’endroit C, de maniere que <lb/>la chaîne AB, étant d’un côté bien arrêtée au tablier A du Pont, & </s> <s xml:id="echoid-s7288" xml:space="preserve"><lb/>de l’autre à l’extrémité B de la flêche, on tire la chaîne DE pour <lb/>baiſſer la baſcule, tandis que l’extrêmité B décrit l’arc BG, l’extrê-<lb/>mité A du Pont décrit l’arc AF; </s> <s xml:id="echoid-s7289" xml:space="preserve">ce Pont auroit ſon mérite, ſi, pour <lb/>loger les flêches, il ne falloit un trop grand eſpace qui rétraiſſit <lb/>beaucoup le paſſage du Rempart au-deſſus de la Porte, ce qui peut <lb/>gêner le charroy du Canon & </s> <s xml:id="echoid-s7290" xml:space="preserve">les autresſervices du Rempart: </s> <s xml:id="echoid-s7291" xml:space="preserve">d’ail-<lb/>leurs, on ne peut voûter le deſſus de la Porte, à moins qu’on ne faſſe <lb/>une Voûte extrêmement élevée, qui ne conviendroit point, parce <pb o="38" file="0328" n="342" rhead="LA SCIENCE DES INGENIEURS,"/> que le bâtiment de deſſus ſeroit trop en vûë auſſi-bien que la façade. <lb/></s> <s xml:id="echoid-s7292" xml:space="preserve">Cependant, c’eſt une neceſſité que le paſſage des Portes ſoit couvert <lb/>à l’épreuve de la bombe, pour prévenir les accidens qui pourroient <lb/>arriver en tems de Siége, puiſqui’il n’en faudroit qu’une pour y <lb/>cauſer un grand deſordre.</s> <s xml:id="echoid-s7293" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7294" xml:space="preserve">Le Profil, qui eſt ſur la Planche 13, repreſente une fermeture de <lb/>Portes meilleure que la précédente; </s> <s xml:id="echoid-s7295" xml:space="preserve">à l’extrêmité I du tablier eſt <lb/> <anchor type="note" xlink:label="note-0328-01a" xlink:href="note-0328-01"/> une chaîne IG de chaque côté, qui étant attachée par l’un de ſes <lb/>bouts, l’autre va paſſer ſur deux poulies G & </s> <s xml:id="echoid-s7296" xml:space="preserve">F, & </s> <s xml:id="echoid-s7297" xml:space="preserve">eſt arrêtée en-<lb/>ſuite à l’endroit K de la Porte HK, qui eſt ſuſpenduë en l’air quand <lb/>le Pont eſt baiſſé, & </s> <s xml:id="echoid-s7298" xml:space="preserve">ſe ferme quand le Pont eſt levé en tournant <lb/>ſur des tourrillons H: </s> <s xml:id="echoid-s7299" xml:space="preserve">car tandis que le Pont en ſe levant décrit <lb/>l’arc IG, la Porte décrit l’arc KL, ce qui ſe fait en tirant la chaîne <lb/>KE vers L; </s> <s xml:id="echoid-s7300" xml:space="preserve">&</s> <s xml:id="echoid-s7301" xml:space="preserve">, pour juger encore mieux comme ſe ferme cette <lb/>Porte, il n’y a qu’à jetter les yeux ſur le Profil qui eſt coupé ſur la <lb/>largeur CD, on y verra les poulies Mm, & </s> <s xml:id="echoid-s7302" xml:space="preserve">la diſpoſition de leur <lb/>crapaudines: </s> <s xml:id="echoid-s7303" xml:space="preserve">j’ajouterai, qu’on pratique un Guichet dans la Porte, <lb/>afin que lorſqu’elle eſt baiſſée on puiſſe aller fermer les verroux de <lb/>la baſcule.</s> <s xml:id="echoid-s7304" xml:space="preserve"/> </p> <div xml:id="echoid-div331" type="float" level="3" n="4"> <note position="left" xlink:label="note-0328-01" xlink:href="note-0328-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>13.</note> </div> <p> <s xml:id="echoid-s7305" xml:space="preserve">Comme il y a long-tems qu’on s’eſt aperçû que les Ponts-Levis à <lb/>flêches étoient ſujets à pluſieurs inconveniens, on les a fait a baſ-<lb/>cule comme on le voit dans le Profil qui eſt ſur la Planche 15; </s> <s xml:id="echoid-s7306" xml:space="preserve">ce <lb/>Pont eſt compoſé de pluſieurs poutrelles, comme IF, qui ont en-<lb/>viron 28 pieds de longueur. </s> <s xml:id="echoid-s7307" xml:space="preserve">Une partie de ces poutrelles, étant re-<lb/>couverte de madriers, compoſent par leur aſſemblage le tablier <lb/>HF, & </s> <s xml:id="echoid-s7308" xml:space="preserve">le reſte comme HI, (qui eſt ce que l’on nomme baſcule) <lb/>ſert de contre-poids pour donner le mouvement au Pont par le <lb/>moyen des tourrillons qui ſont à l’extrêmité d’une bare de fer, qui, <lb/>étant entretenuë avec les poutrelles, traverſe toute la largeur de la <lb/>Porte à l’endroit du ſole: </s> <s xml:id="echoid-s7309" xml:space="preserve">cette baſcule eſt logée dans une cave que <lb/>l’on nomme auſſi Cage de la baſcule, qui eſt couverte par un Pont dor-<lb/>mant compoſé de poutrelles & </s> <s xml:id="echoid-s7310" xml:space="preserve">de madriers. </s> <s xml:id="echoid-s7311" xml:space="preserve">Quand on met le Pont-<lb/>Levis en mouvement, la baſcule décrit l’arc IK, tandis que le ta-<lb/>blier décrit l’autre FG pour deſcendre dans la cave; </s> <s xml:id="echoid-s7312" xml:space="preserve">on fait un eſ-<lb/>calier pratiqué dans l’un des piés-droits, comme il eſt figuré au Plan <lb/>de la Porte qui répond au Profil dont nous parlons.</s> <s xml:id="echoid-s7313" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7314" xml:space="preserve">On ne fait plus preſentement de ces ſortes de Ponts, parce qu’à <lb/>le bien prendre ils ſont encore plus défectueux que les autres à flê-<lb/>ches; </s> <s xml:id="echoid-s7315" xml:space="preserve">car la cage eſt d’une grande dépenſe, & </s> <s xml:id="echoid-s7316" xml:space="preserve">affoiblit beaucoup <lb/>le mur de face: </s> <s xml:id="echoid-s7317" xml:space="preserve">ils ſont ſujets à des réparations continuelles, & </s> <s xml:id="echoid-s7318" xml:space="preserve">diffi-<lb/>ciles à manœuvrer. </s> <s xml:id="echoid-s7319" xml:space="preserve">Un autre inconvenient, c’eſt que la cage qu’il <pb o="39" file="0329" n="343" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> faut faire pour loger la baſcule ne peut avoir lieu qu’aux Places <lb/>dont les Foſſés ſont à ſec, car s’ils étoient inondés, il faudroit que <lb/>le rez-de-Chauſſée de la Porte fut au moins de 15 pieds au-deſſus <lb/>du niveau des plus hautes eaux; </s> <s xml:id="echoid-s7320" xml:space="preserve">autrement, elle pénétreroit dans la <lb/>cave, en dégraderoit la maçonnerie, & </s> <s xml:id="echoid-s7321" xml:space="preserve">cauſeroit une grande diffi-<lb/>culté de hauſſer & </s> <s xml:id="echoid-s7322" xml:space="preserve">baiſſer le Pont, ſur-tout en hyver, où venant à <lb/>ſe gêler, la baſcule pourroit ſe trouver priſe.</s> <s xml:id="echoid-s7323" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7324" xml:space="preserve">On preſenta en 1708. </s> <s xml:id="echoid-s7325" xml:space="preserve">à M. </s> <s xml:id="echoid-s7326" xml:space="preserve">le Pelletier de Souſy, pour lors Di-<lb/>recteur General des Fortifications de France, un modele de Pont-<lb/>Levis fort ingenieux, qui a été executé à Givet en 1716.</s> <s xml:id="echoid-s7327" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7328" xml:space="preserve">Si l’on jette les yeux ſur le troiſiéme Deſſein de la Planche 18, <lb/> <anchor type="note" xlink:label="note-0329-01a" xlink:href="note-0329-01"/> l’on verra que le tablier B, ſe léve par le moyen de deux flêches <lb/>qui ont 12 ou 13 pieds de longueur, ſur 10 à 11 pouces de groſ-<lb/>ſeur au milieu, revenant à 8 & </s> <s xml:id="echoid-s7329" xml:space="preserve">9 par les bouts; </s> <s xml:id="echoid-s7330" xml:space="preserve">elles ſont traverſées <lb/>par le milieu d’un axe de fer d’environ deux pouces quarrés, & </s> <s xml:id="echoid-s7331" xml:space="preserve">de <lb/>16 à 18 pouces de longueur: </s> <s xml:id="echoid-s7332" xml:space="preserve">les deux bouts qui excedent la flêche <lb/>ſont arrondis ſur 3 à 4 pouces de longueur & </s> <s xml:id="echoid-s7333" xml:space="preserve">tournent ſur deux <lb/>crapaudines, dont l’une eſt poſée au milieu du tableau de la Porte <lb/>au point G, & </s> <s xml:id="echoid-s7334" xml:space="preserve">l’autrc faitc en S, paſſc au-devant de la flêche com-<lb/>me le marque le Profil au même point G, laquelle eſt attachée par <lb/>un Goujon de fer à chacune de ſes extrêmités & </s> <s xml:id="echoid-s7335" xml:space="preserve">ſcellée en plomb <lb/>dans la partie du tableau la plus avancée; </s> <s xml:id="echoid-s7336" xml:space="preserve">ces Goujons ſont faits en <lb/>vis par leur extrêmité pour recevoir un écrouë ſemblable à ceux <lb/>que l’on met aux eſſieux des Carroſſes, afin de pouvoir démonter <lb/>les flêches lorſqu’il faut les renouveller.</s> <s xml:id="echoid-s7337" xml:space="preserve"/> </p> <div xml:id="echoid-div332" type="float" level="3" n="5"> <note position="right" xlink:label="note-0329-01" xlink:href="note-0329-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>18. <lb/><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s7338" xml:space="preserve">Les deux fleches ſont liées au tablier du pont B, & </s> <s xml:id="echoid-s7339" xml:space="preserve">à la baſcu-<lb/>le H, par deux barreaux de fer arrondis, ou à pans, qui ont leur <lb/>mouvement à chaque extrémité dans des œüillets, ou par des dou-<lb/>bles charnieres, de ſorte que tirant la chaîne I, à meſure que la <lb/>baſcule deſcend & </s> <s xml:id="echoid-s7340" xml:space="preserve">tourne ſur les tourillons K, le pont monte juſ-<lb/>qu’à ce que tout ait pris une ſituation verticale. </s> <s xml:id="echoid-s7341" xml:space="preserve">Quoique ce mou-<lb/>vement ſoit plus compoſé que celui des baſcules ordinaires, il n’a <lb/>pas laiſſé de fort bien réuſſir à Givet & </s> <s xml:id="echoid-s7342" xml:space="preserve">à Toul, où on l’a mis en œu-<lb/>vre: </s> <s xml:id="echoid-s7343" xml:space="preserve">mais ce pont, que l’on nomme Ziczague, n’eſt pas d’une in-<lb/>vention nouvelle, comme on l’a voulu inſinuer à Mr. </s> <s xml:id="echoid-s7344" xml:space="preserve">Pelletier; <lb/></s> <s xml:id="echoid-s7345" xml:space="preserve">il s’en trouve de ſemblables en pluſieurs Villes d’Allemagne, qui <lb/>y on été conſtruits depuis long-tems, entr’autres à Hambourg & </s> <s xml:id="echoid-s7346" xml:space="preserve"><lb/>à Lubee.</s> <s xml:id="echoid-s7347" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div334" type="section" level="2" n="115"> <head xml:id="echoid-head263" style="it" xml:space="preserve">Nouvelle maniere de Pont-Levis.</head> <p> <s xml:id="echoid-s7348" xml:space="preserve">Après avoir examiné les differentes ſortes de Ponts qu’on a <lb/> <anchor type="note" xlink:label="note-0329-02a" xlink:href="note-0329-02"/> <pb o="40" file="0330" n="344" rhead="LA SCIENCE DES INGENIEURS,"/> imaginé pour fermer les Portes des Villes, j’ai cherché ſi je ne trou-<lb/>verois pas quelque moyen plus ſimple que ceux que je viens de rap-<lb/>porter: </s> <s xml:id="echoid-s7349" xml:space="preserve">car, à mon ſens, ce n’eſt point aſſés de faire la deſcription <lb/>des choſes qui ſont en uſage; </s> <s xml:id="echoid-s7350" xml:space="preserve">ceux qui ſe mêlent d’écrire ſont <lb/>dans une eſpece d’obligation de travailler à les perfectionner: </s> <s xml:id="echoid-s7351" xml:space="preserve">au-<lb/>trement, les arts ne font point de progrés; </s> <s xml:id="echoid-s7352" xml:space="preserve">les livres ſe multiplient, <lb/>ſans que ceux qui les liſent en deviennent plus éclairés. </s> <s xml:id="echoid-s7353" xml:space="preserve">Pour enten-<lb/>dre parfaitement le Pont que j’ai imaginé, il eſt à propos que j’ex-<lb/>poſe le raiſonnement que je me ſuis fait à moi-même: </s> <s xml:id="echoid-s7354" xml:space="preserve">le voici.</s> <s xml:id="echoid-s7355" xml:space="preserve"/> </p> <div xml:id="echoid-div334" type="float" level="3" n="1"> <note position="right" xlink:label="note-0329-02" xlink:href="note-0329-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>20.</note> </div> <p> <s xml:id="echoid-s7356" xml:space="preserve">L’on ſupoſe que AB eſt un levier ſans peſanteur, dans le milieu <lb/> <anchor type="note" xlink:label="note-0330-01a" xlink:href="note-0330-01"/> duquel on a ſuſpendu un poids D, qu’on regardera comme réu-<lb/>ni au point C; </s> <s xml:id="echoid-s7357" xml:space="preserve">qu’une des extrêmités B peut tourner au tour d’un <lb/>point fixe; </s> <s xml:id="echoid-s7358" xml:space="preserve">qu’à l’autre extrémité A, l’on a attaché une corde, qui <lb/>va paſſer ſur deux poulies E & </s> <s xml:id="echoid-s7359" xml:space="preserve">F, pour ſoutenir un poids G, qui <lb/>eſt en équilibre avec celui du levier; </s> <s xml:id="echoid-s7360" xml:space="preserve">enfin, que la verticale BE, eſt <lb/>égale à la longueur BA.</s> <s xml:id="echoid-s7361" xml:space="preserve"/> </p> <div xml:id="echoid-div335" type="float" level="3" n="2"> <note position="left" xlink:label="note-0330-01" xlink:href="note-0330-01a" xml:space="preserve">Voyez la <lb/>Figure qui <lb/>eſt au bas <lb/>de la Plan-<lb/>che 20.</note> </div> <p> <s xml:id="echoid-s7362" xml:space="preserve">Pour que le poids G ſoit en équilibre avec celui qui répond au <lb/>point C, il faut, ſelon les principes de la mécanique, que la pé-<lb/>ſanteur de l’un ſoit à celle de l’autre<unsure/> dans la raiſon réciproque <lb/>des perpendiculalres, tirées du point d’apui B, ſur les lignes de di-<lb/>rection AE & </s> <s xml:id="echoid-s7363" xml:space="preserve">CD, ainſi le poids G doit être au poids C, comme <lb/>BC eſt à BI, c’eſt-à-dire, comme le côté d’un quarré eſt à ſa dia-<lb/>gonalle, par conſequent l’on pourra, quand on le jugera à propos, <lb/>à la place des poids G & </s> <s xml:id="echoid-s7364" xml:space="preserve">C, prendre les lignes BC & </s> <s xml:id="echoid-s7365" xml:space="preserve">BI, puis qu’el-<lb/>les ſont dans le même raport. </s> <s xml:id="echoid-s7366" xml:space="preserve">Or ſi l’on donnoit au levier AB une <lb/>ſituation oblique KB, il eſt conſtant que l’équilibre ſeroit rom-<lb/>pu, puiſque le poids D, n’agiſſant plus ſelon une direction perpen-<lb/>diculaire au levier KB, ne fera pas tant d’effort qu’auparavant, <lb/>pour contrebalancer l’action du poids G, c’eſt pourquoi ce der-<lb/>nier deſcendra le long de la verticale FH avec précipitation, tant <lb/>que le point K ſoit parvenu en E, ce qui ne peut arriver autre-<lb/>ment, à moins que le poids G en deſcendant ne rencontre des <lb/>obſtacles qui diminuent l’action de ſa peſanteur abſoluë: </s> <s xml:id="echoid-s7367" xml:space="preserve">ſi ces obſ-<lb/>tacles étoient cauſés par des plans inclinés, dont les differentes <lb/>inclinaiſons fuſſent proportionnées aux ſinus des angles, comme <lb/>MLB qui deviennent toûjours plus petits, à meſure que le levier <lb/>approcbe de la verticale, il eſt certain que ces plans inclinés <lb/>cauſeront l’équilibre du poids D avec le poids G, dans quelque <lb/>ſituation que ſoit le levier; </s> <s xml:id="echoid-s7368" xml:space="preserve">mais, pour que cela arrive, il faut que <lb/>les plans changent à tout moment, & </s> <s xml:id="echoid-s7369" xml:space="preserve">que chacun en particulier <lb/>comprene un eſpace infiniment petit, d’où il s’enſuit qu’ils forme- <pb file="0331" n="345"/> <pb file="0331a" n="346"/> <anchor type="figure" xlink:label="fig-0331a-01a" xlink:href="fig-0331a-01"/> <pb file="0332" n="347"/> <pb file="0333" n="348"/> <pb file="0333a" n="349"/> <anchor type="figure" xlink:label="fig-0333a-01a" xlink:href="fig-0333a-01"/> <pb file="0334" n="350"/> <pb file="0335" n="351"/> <pb file="0335a" n="352"/> <anchor type="figure" xlink:label="fig-0335a-01a" xlink:href="fig-0335a-01"/> <pb file="0336" n="353"/> <pb file="0337" n="354"/> <pb file="0337a" n="355"/> <anchor type="figure" xlink:label="fig-0337a-01a" xlink:href="fig-0337a-01"/> <pb file="0338" n="356"/> <pb o="41" file="0339" n="357" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> ront tous enſemble une courbe rSVX, ainſi la queſtion ſe reduit <lb/>à ſavoir, comme il faut conſtruire cette courbe, pour que les deux <lb/>poids ſoient toûjours en équilibre, dans toutes les ſituations où ſe <lb/>peut trouver le levier, en venant de A en E.</s> <s xml:id="echoid-s7370" xml:space="preserve"/> </p> <div xml:id="echoid-div336" type="float" level="3" n="3"> <figure xlink:label="fig-0331a-01" xlink:href="fig-0331a-01a"> <image file="0331a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0331a-01"/> </figure> <figure xlink:label="fig-0333a-01" xlink:href="fig-0333a-01a"> <image file="0333a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0333a-01"/> </figure> <figure xlink:label="fig-0335a-01" xlink:href="fig-0335a-01a"> <image file="0335a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0335a-01"/> </figure> <figure xlink:label="fig-0337a-01" xlink:href="fig-0337a-01a"> <image file="0337a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0337a-01"/> </figure> </div> <p> <s xml:id="echoid-s7371" xml:space="preserve">Remarquez que quand l’extremité A du levier BA, décrira le <lb/>quart de cercle ANE en venant joindre le point E, l’extrémité C <lb/>de la ligne BC, décrira le quart de cercle CQ; </s> <s xml:id="echoid-s7372" xml:space="preserve">or quand le point <lb/>A ſera parvenu en K & </s> <s xml:id="echoid-s7373" xml:space="preserve">en N, le poids C ſera parvenu en L & </s> <s xml:id="echoid-s7374" xml:space="preserve">en <lb/>O, & </s> <s xml:id="echoid-s7375" xml:space="preserve">monté d’une hauteur exprimée par les perpendiculaires LM <lb/>& </s> <s xml:id="echoid-s7376" xml:space="preserve">OP, qui ſont les ſinus des angles formés par le levier & </s> <s xml:id="echoid-s7377" xml:space="preserve">le <lb/>rayon AB; </s> <s xml:id="echoid-s7378" xml:space="preserve">on peut donc dire que tous les ſinus du quart de cer-<lb/>cle CQ, en commençant depuis le plus petit, exprimeront de ſui-<lb/>te le chemin que le poids C fera dans le tems que l’extrémité A <lb/>du levier parcourra les points du quart de cercle ANE; </s> <s xml:id="echoid-s7379" xml:space="preserve">mais il <lb/>ſuffit pour que les deux poids L & </s> <s xml:id="echoid-s7380" xml:space="preserve">G ſoient en équilibre, dans la <lb/>ſituation où eſt le levier KB, que l’élevation ML, du premier, <lb/>ſoit à la deſcente verticale rR du ſecond, en raiſon reciproque de <lb/>la peſanteur abſoluë de ces deux poids <emph style="sub">*</emph>: </s> <s xml:id="echoid-s7381" xml:space="preserve">& </s> <s xml:id="echoid-s7382" xml:space="preserve">comme la même <lb/> <anchor type="note" xlink:label="note-0339-01a" xlink:href="note-0339-01"/> choſe doit arriver dans toutes les autres ſituations du levier & </s> <s xml:id="echoid-s7383" xml:space="preserve">du <lb/>poids G, puiſque leur mouvement dépend toûjours l’un de l’au-<lb/>tre, quand le poids C ſera en O, & </s> <s xml:id="echoid-s7384" xml:space="preserve">le poids G en V, l’on aura <lb/>encore que le poids G eſt au poids O, comme l’élevation OP eſt <lb/>à la deſcente verticale rT; </s> <s xml:id="echoid-s7385" xml:space="preserve">& </s> <s xml:id="echoid-s7386" xml:space="preserve">ſi à la place des poids C & </s> <s xml:id="echoid-s7387" xml:space="preserve">G, on <lb/>prend les lignes BI & </s> <s xml:id="echoid-s7388" xml:space="preserve">BC, qui ſont en même raiſon, on pourra <lb/>connoître le raport de tous les ſinus, comme LM & </s> <s xml:id="echoid-s7389" xml:space="preserve">OP, avec les <lb/>verticales rR & </s> <s xml:id="echoid-s7390" xml:space="preserve">rT: </s> <s xml:id="echoid-s7391" xml:space="preserve">d’un autre côté il ſera aiſé de déterminer les <lb/>perpendiculaires RS & </s> <s xml:id="echoid-s7392" xml:space="preserve">TV, pour avoir les points S & </s> <s xml:id="echoid-s7393" xml:space="preserve">V de la cour-<lb/>be; </s> <s xml:id="echoid-s7394" xml:space="preserve">puiſque la diſtance du centre de la poulie F à chaque point <lb/>S & </s> <s xml:id="echoid-s7395" xml:space="preserve">V, ſera toûjours égale à la difference de la longueur, de la <lb/>corde compriſe depuis A juſqu’en G, aux parties KEF & </s> <s xml:id="echoid-s7396" xml:space="preserve">NEF, <lb/>qui diminuent toûjours à meſure que le levier aproche de la ver-<lb/>ticale; </s> <s xml:id="echoid-s7397" xml:space="preserve">ainſi nous avons tout ce qu’il faut pour conſtruire la cour-<lb/>be qui ſera geometrique, puiſque nous n’employons dans ſa conſ-<lb/>truction que des grandeurs, dont la relation eſt connuë: </s> <s xml:id="echoid-s7398" xml:space="preserve">& </s> <s xml:id="echoid-s7399" xml:space="preserve">com-<lb/>me ce ſont les ſinus qui deſignent le raport de ces grandeurs, il <lb/>m’a paru que pour donner un nom à la courbe, qui fût tiré de ſa <lb/>génération même, il étoit naturel de l’appeller la Sinuſoide.</s> <s xml:id="echoid-s7400" xml:space="preserve"/> </p> <div xml:id="echoid-div337" type="float" level="3" n="4"> <note position="right" xlink:label="note-0339-01" xlink:href="note-0339-01a" xml:space="preserve">Voyez le <lb/>Cours de <lb/>Mathe-<lb/>matiq. art. <lb/>799. & <lb/>300.</note> </div> </div> <div xml:id="echoid-div339" type="section" level="2" n="116"> <head xml:id="echoid-head264" style="it" xml:space="preserve">Conſtruction de la Sinuſoide.</head> <p> <s xml:id="echoid-s7401" xml:space="preserve">Il faut d’abord diviſer le quart de cercle CQ, en un grand nom- <pb o="42" file="0340" n="358" rhead="LA SCIENCE DES INGENIEURS,"/> bre de parties égales, par chaque point de diviſion comme L & </s> <s xml:id="echoid-s7402" xml:space="preserve">O, <lb/>abaiſſer les perpendiculaires LM, OP, &</s> <s xml:id="echoid-s7403" xml:space="preserve">c. </s> <s xml:id="echoid-s7404" xml:space="preserve">ſur le demi diamêtre CB, <lb/>tirer les rayons BK, BN, &</s> <s xml:id="echoid-s7405" xml:space="preserve">c. </s> <s xml:id="echoid-s7406" xml:space="preserve">auſſi bien que les lignes KE, NE, &</s> <s xml:id="echoid-s7407" xml:space="preserve">c. <lb/></s> <s xml:id="echoid-s7408" xml:space="preserve">enſuite chercher aux lignes BC, BI, & </s> <s xml:id="echoid-s7409" xml:space="preserve">au ſinus LM, (que nous <lb/>regarderons comme le plus petit de tous), une quatriéme propor-<lb/>tionnelle que l’on portera ſur la verticale FH, en commençant <lb/>du point r, qui répond immediatement au-deſſous du poids G, & </s> <s xml:id="echoid-s7410" xml:space="preserve"><lb/>ſupoſant que rR ſoit égale à la quatriéme proportionnelle qu’on <lb/>vient de trouver, on élevera au point R la perpendiculaire RS in-<lb/>definie; </s> <s xml:id="echoid-s7411" xml:space="preserve">on cherchera de même aux lignes BC, BI, & </s> <s xml:id="echoid-s7412" xml:space="preserve">au ſinus OP, <lb/>(que nous ſupoſons ſuivre immediatement le plus petit LM,) une <lb/>quatriéme proportionnelle qu’on portera depuis r juſqu’en T, & </s> <s xml:id="echoid-s7413" xml:space="preserve"><lb/>on élevera encore la perpendiculaire TV.</s> <s xml:id="echoid-s7414" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7415" xml:space="preserve">Le triangle CBI étant rectangle & </s> <s xml:id="echoid-s7416" xml:space="preserve">izocelle, il ſera bien aiſé de <lb/>trouver toutes les quatriémes proportionnelles dont nous avons be-<lb/>ſoin; </s> <s xml:id="echoid-s7417" xml:space="preserve">car ſi l’on prend chaque ſinus comme LM ou OP, pour le <lb/>côté d’un quarré, la diagonalle de ce quarré ſera quatriéme propor-<lb/>tionnelle aux lignes BC, BI, & </s> <s xml:id="echoid-s7418" xml:space="preserve">au ſinus qu’on aura pris pour côté <lb/>du quarré, ce qui eſt bien évident à cauſe des triangles ſemblables.</s> <s xml:id="echoid-s7419" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7420" xml:space="preserve">Après qu’on aura toutes les perpondiculairoc<unsure/>, comme R, S, T, <lb/>V, &</s> <s xml:id="echoid-s7421" xml:space="preserve">c. </s> <s xml:id="echoid-s7422" xml:space="preserve">on tirera une ligne d e, égale à la longueur de la cor-<lb/>de AEFG, l’on prendra dans cette ligne (en commençant de l’ex-<lb/>trémité d,) la partie d f, égale à la diſtance du centre de la poulie <lb/>F au poids G, c’eſt-à-dire, égale à cette partie de la corde qui eſt <lb/>paralelle à la verticale FH, quand le levier AB eſt horiſontal; </s> <s xml:id="echoid-s7423" xml:space="preserve">on <lb/>prendra la difference de la ligne KE, quirépond aurayon de la pre-<lb/>miere diviſion à la ligne AE, & </s> <s xml:id="echoid-s7424" xml:space="preserve">on portera cette difference depuis <lb/>f juſqu’en h, alors on prendra la longueur d h avec un compas, <lb/>pour décrire un arc qui aura pour centre celui de la poulie F, & </s> <s xml:id="echoid-s7425" xml:space="preserve"><lb/>cet arc venant couper la perpendiculaire RS, donnera le point <lb/>S qui eſt un de ceux de la courbe, par le moyen duquel on aura <lb/>l’ordonnée S a & </s> <s xml:id="echoid-s7426" xml:space="preserve">ſon abciſſe r a; </s> <s xml:id="echoid-s7427" xml:space="preserve">de même prenant la difference <lb/>des lignes NE & </s> <s xml:id="echoid-s7428" xml:space="preserve">AE, pour la porter de f en j, ſi l’on ouvre le com-<lb/>pas de l’intervale d j, & </s> <s xml:id="echoid-s7429" xml:space="preserve">que du centre F de la poulie, on décrive <lb/>un arc qui vienne couper la perpendiculaire TV, on aura un autre <lb/>point V de la courbe, qui donnera l’ordonnée V b & </s> <s xml:id="echoid-s7430" xml:space="preserve">l’abciſſe BIr; <lb/></s> <s xml:id="echoid-s7431" xml:space="preserve">enfin le point N étant parvenu en E, toute la ligne AE pourra être <lb/>priſe pour ſa difference avec zero, & </s> <s xml:id="echoid-s7432" xml:space="preserve">le portant depuis F juſqu’en <lb/>K, ouvrant le compas de l’intervale d K, on décrira du centre or-<lb/>dinaire, un arc qui venant rencontrer la derniere perpendiculaire <lb/>h X, donnera le point X qui ſera celui de la courbe, où va ſe ter- <pb o="43" file="0341" n="359" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> miner le poids G, quand le levier AB eſt vertical.</s> <s xml:id="echoid-s7433" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7434" xml:space="preserve">Je croi qu’il n’eſt pas beſoin de dire, que, pour tracer la cour-<lb/>be avec beaucoup de juſteſſe, il faut prendre les ſinus bien près les <lb/>uns des autres, afin d’avoir un grand nombre de points comme S, V, <lb/>&</s> <s xml:id="echoid-s7435" xml:space="preserve">c. </s> <s xml:id="echoid-s7436" xml:space="preserve">Il eſt à propos de remarquer, que la plus grande ordonnée ZX, <lb/>ou rH, de la courbe, eſt égale à la perpendiculaire BI, c’eſt-à-dire <lb/>au côté du quarré, dont la diagonalle ſeroit de même longueur que <lb/>le levier AB, car comme la ligne rH ſera la plus grande de tou-<lb/>tes les quatriémes proportionnelles, qu’on aura été obligé de cher-<lb/>cher pour tracer la courbe, on ne l’aura trouvée que lors que le le-<lb/>vier AB ſera vertical, & </s> <s xml:id="echoid-s7437" xml:space="preserve">alors comme il formera un angle droit <lb/>avec l’horiſontal, le ſinus de cet angle ſera égal au rayon BQ, par <lb/>conſequent l’on aura BC, BI:</s> <s xml:id="echoid-s7438" xml:space="preserve">: BQ, rH; </s> <s xml:id="echoid-s7439" xml:space="preserve">mais comme dans cette <lb/>proportion les deux antecedens BC & </s> <s xml:id="echoid-s7440" xml:space="preserve">BQ ſont égaux, étant rayon <lb/>d’un même cercle, les deux conſequent BI & </s> <s xml:id="echoid-s7441" xml:space="preserve">rH le ſeront donc <lb/>auſſi.</s> <s xml:id="echoid-s7442" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7443" xml:space="preserve">Par cette Remarque on pourra toûjours (connoiſſant la longueur <lb/>du lévier AB,) ſavoir à quel point de la verticale FH ira ſe termi-<lb/>ner la baſe HX de la Sinuſoide, quand on aura déterminé la po-<lb/>ſition du point r, ou cette courbe doit prendre ſon origine.</s> <s xml:id="echoid-s7444" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7445" xml:space="preserve">L’on remarquera encore que tout ce qu’on vient de dire peut <lb/>s’apliquer aux Ponts-Levis; </s> <s xml:id="echoid-s7446" xml:space="preserve">car le lévier AB peut être pris pour le <lb/>profil du tablier qui tourne autour de ſes tourillons B, & </s> <s xml:id="echoid-s7447" xml:space="preserve">dont la <lb/>péſanteur eſt réünie au centre de gravité C, ainſi il ne s’agit plus <lb/>que d’executer tout ce qui doit en faciliter le mouvement, & </s> <s xml:id="echoid-s7448" xml:space="preserve">c’eſt <lb/>ce que lon va voir dans l’Aplication ſuivante.</s> <s xml:id="echoid-s7449" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div340" type="section" level="2" n="117"> <head xml:id="echoid-head265" style="it" xml:space="preserve">Aplication de la Sinuſoide aux Pont-Levis qui ſervent à <lb/>fermer l’Entrée des Villes.</head> <p> <s xml:id="echoid-s7450" xml:space="preserve">Ayant déterminé la largeur IK de la porte, qui eſt comme nous <lb/>l’avons dit de 9 pieds ou 9 pieds & </s> <s xml:id="echoid-s7451" xml:space="preserve">demi, il faut à droit & </s> <s xml:id="echoid-s7452" xml:space="preserve">à gauche <lb/>reculer les piés-droits de la Voûte d’environ 4 pieds au-delà des ta-<lb/>bleaux IG & </s> <s xml:id="echoid-s7453" xml:space="preserve">KG, afin de pratiquer deux niches pour y loger les <lb/>couliſſes BF, le long deſquelles doivent rouller les poids qui ſervi-<lb/>ront à donner le mouvement au Pont que nous nommerons par la <lb/>ſuite poids de baſcule. </s> <s xml:id="echoid-s7454" xml:space="preserve">L’élevation d’une des couliſſes eſtrepreſentée <lb/>au profil de la porte où l’on voit que la courbe STE, n’eſt autre <lb/>choſe que la Sinuſoide executée en Maçonnerie. </s> <s xml:id="echoid-s7455" xml:space="preserve">Ce profil montre <lb/>auſſi que le poids de baſcule D, eſt attaché à une chaîne qui paſſe <lb/>ſur deux poulies B & </s> <s xml:id="echoid-s7456" xml:space="preserve">A, pour aller joindre le chevet C, du Pont.</s> <s xml:id="echoid-s7457" xml:space="preserve"> <pb o="44" file="0342" n="360" rhead="LA SCIENCE DES INGENIEURS,"/> Car l’on doit concevoir que derriere les tableaux de la Porte, on <lb/>a ménagé des fentes dans la maçonnerie pour y placer les poulies, <lb/>afin que la chaîne, qui doit donner le mouvement au Pont, puiſſe <lb/>aller & </s> <s xml:id="echoid-s7458" xml:space="preserve">venir librement; </s> <s xml:id="echoid-s7459" xml:space="preserve">c’eſt pourquoi l’on ſupoſe que cette chaîne <lb/>eſt ronde. </s> <s xml:id="echoid-s7460" xml:space="preserve">On remarquera auſſi que le chevet doit être plus long <lb/>que le Pont n’eſt large, afin que les chaines qui ſont à ſes extrêmi-<lb/>tés ſe trouvent vis-à-vis des poulies.</s> <s xml:id="echoid-s7461" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7462" xml:space="preserve">Si les poids de baſcule ſont en équilibre avec le Pont, il eſt cer-<lb/>tain que par la propriété de la Sinuſoide à quelque point qu’on vou-<lb/>dra du quart de cercle CR, le Pont reſtera toûjours immobile en <lb/>allant de C en R, ſans que les poids l’entraînent, puiſqu’ils demeu-<lb/>reront eux-mêmes en repos aux endroits des couliſſes où ils ſe trou-<lb/>veront, par conſéquent il ſuffira que l’on aide tant ſoit peu les <lb/>poids à vaincre le frotement pour que le Pont ſe lêve, ſans être <lb/>obligé d’employer une force conſidérable pour lui faire décrire le <lb/>quart de cercle CR, ce qui ſe fera d’un mouvement uniforme ſans <lb/>ébranlement ni ſecouſſe, de même quand on voudra le baiſſer, on <lb/>n’aura qu’à pouſſer le tablier pour le faire deſcendre, enſuite paſſer <lb/>deſſus pour l’aller arrêter ſur le dernier chevalet du Pont dormant <lb/>avec les verroux.</s> <s xml:id="echoid-s7463" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7464" xml:space="preserve">Comme mon deſſein n’eſt pas que l’on touche aux poids de baſ-<lb/>cule, par la difficulté qu’on auroit d’y atteindre, il n’y a pas de <lb/>moyen plus ſimple pour obliger ces poids de deſcendre, que d’ac-<lb/>crocher deux chaînes au Pont environ à 3 pieds en deça du chevet, <lb/>dont chacune ira paſſer ſur une poulie ſituée au milieu des tableaux <lb/>de la porte & </s> <s xml:id="echoid-s7465" xml:space="preserve">élevée de 9 pieds au-deſſus du rez-de-Chauſſée; </s> <s xml:id="echoid-s7466" xml:space="preserve">de <lb/>ſorte que quand on voudra fermer la porte, il ſuffira qu’il y ait un <lb/>homme qui tire chaque chaîne pour lever le Pont, dont le mou-<lb/>vement eſt ſi naturel, qu’il ſeroit inutile d’en parler davantage: </s> <s xml:id="echoid-s7467" xml:space="preserve">ainſi <lb/>je paſſe à pluſieurs détails qu’il eſt neceſſaire d’expliquer, afin de <lb/>ſavoir comme on pourra connoître la peſanteur des poids de la <lb/>baſcule, leur groſſeur, la grandeur des couliſſes, & </s> <s xml:id="echoid-s7468" xml:space="preserve">les autres cir-<lb/>conſtances eſſentielles à l’intelligence de ce Pont.</s> <s xml:id="echoid-s7469" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7470" xml:space="preserve">La premiere choſe qu’il faut ſavoir, c’eſt qu’un pied cube de bois <lb/>de chêne péſe 60 liv. </s> <s xml:id="echoid-s7471" xml:space="preserve">& </s> <s xml:id="echoid-s7472" xml:space="preserve">qu’un pied cube de fer en péſe 580; </s> <s xml:id="echoid-s7473" xml:space="preserve">ainſi <lb/>examinant quelles ſont les dimenſions des piéces qui doivent com-<lb/>poſer la charpente du Pont, il ſera aiſé de connoître combien il y <lb/>entre de pieds cubes de bois, par conſéquent combien cette char-<lb/>pente doit péſer. </s> <s xml:id="echoid-s7474" xml:space="preserve">Si l’on fait le chevetplus long qu’à l’ordinaire, afin <lb/>que les chaînes qui doivent être attachées à ſes extrêmités ſe trou-<lb/>vent directement vis-à-vis les poulies, il faudra lui donner 14 pieds <pb o="45" file="0343" n="361" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> de longueur ſur 10 à 10 pouces, pour que cette piéce, qui a un grand <lb/>effort à ſoutenir quand on met le Pont en mouvement, ne ſoit point <lb/>en danger de ſe rompre par la ſuite.</s> <s xml:id="echoid-s7475" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7476" xml:space="preserve">La piéce des tourillons ſe fait toûjours de 10 pieds de longueur ſur <lb/>10 à 10 pouces de groſſeur: </s> <s xml:id="echoid-s7477" xml:space="preserve">il a ſix ſoliveaux de 12 pieds de long <lb/>ſur 5 à 6 pouces de groſſeur ſervant à porter le plancher du Pont, qui <lb/>eſt compoſé de madriers de deux pouces d’épaiſſeur, & </s> <s xml:id="echoid-s7478" xml:space="preserve">qui couvre <lb/>un eſpace de 12 pieds de longueur ſur 10 de largeur; </s> <s xml:id="echoid-s7479" xml:space="preserve">& </s> <s xml:id="echoid-s7480" xml:space="preserve">tout cela en-<lb/>ſemble compoſela charpente du tablier, qui monte à 51 pieds 8 pou-<lb/>ces 4 lignes cubes, qui étant multiplié par 60, donne 3102 l. </s> <s xml:id="echoid-s7481" xml:space="preserve">pour la <lb/>péſanteur de la charpente: </s> <s xml:id="echoid-s7482" xml:space="preserve">ſurquoi il eſt à remarquer, que le chevet <lb/>ayant plus de péſanteur que la piéce des tourillons, les extrêmités du <lb/>Pont ne ſont point égales, ainſi on ne peut pas regarder 3102 liv. <lb/></s> <s xml:id="echoid-s7483" xml:space="preserve">comme un poids qui puiſſe être réüni au centre de gravité du <lb/>Pont, c’eſt-à-dire dans le milieu de ſa longueur. </s> <s xml:id="echoid-s7484" xml:space="preserve">Il faut donc voir <lb/>à quoi peut aller cette difference qui ſera facile à connoître; </s> <s xml:id="echoid-s7485" xml:space="preserve">car <lb/>le chevet contient 9 pieds 8 pouces 8 lignes cubes, & </s> <s xml:id="echoid-s7486" xml:space="preserve">la piéce des <lb/>tourillons ne contient que 6 pieds 11 pouces 8 lignes, par conſé-<lb/>quent la difference eſt de 2 pieds 9 pouces dont la péſanteur monte <lb/>à 165 liv. </s> <s xml:id="echoid-s7487" xml:space="preserve">or ces 165, étant à l’extremité du lévier, font deux fois <lb/>plus d’effet par raport au point d’apui, que s’ils étoient dans le mi-<lb/>lieu du même lévier, c’eſt pourquoi il faut augmenter 3102 liv. </s> <s xml:id="echoid-s7488" xml:space="preserve">de <lb/>165 liv. </s> <s xml:id="echoid-s7489" xml:space="preserve">& </s> <s xml:id="echoid-s7490" xml:space="preserve">alors la péſanteur de la charpente réünie au centre de <lb/>gravité ſera de 3267 liv.</s> <s xml:id="echoid-s7491" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7492" xml:space="preserve">Pour conſerver le plancher des Ponts Levis, on le recouvre de <lb/>barres de fer de 7 pieds de longueur poſées tant plain que vuide, <lb/>elles ont un peu plus de deux pouces de largeur, & </s> <s xml:id="echoid-s7493" xml:space="preserve">il y en entre <lb/>ordinairement 32, & </s> <s xml:id="echoid-s7494" xml:space="preserve">comme chacune eſt attachée avec 4 cram-<lb/>pons, au lieu de 7 pieds de longueur, nous leur en ſupoſerons 7 & </s> <s xml:id="echoid-s7495" xml:space="preserve"><lb/>demi, afin d’y comprendre les crampons, ainſi ces 32 barres feront <lb/>enſemble 240 pieds de long, à quoi il faut encore en ajoûter 6 au-<lb/>tres de chacune 6 pieds de long quiſe mettent au-deſſous du tablier <lb/>pour lier le chevet & </s> <s xml:id="echoid-s7496" xml:space="preserve">la piéce des tourillons avec les poutrelles, ce <lb/>qui fait en tout 276 pieds; </s> <s xml:id="echoid-s7497" xml:space="preserve">& </s> <s xml:id="echoid-s7498" xml:space="preserve">le poids d’un pied de ces ſortes de <lb/>barres étant de 3 liv. </s> <s xml:id="echoid-s7499" xml:space="preserve">elles péſeront donc enſemble 828 liv. </s> <s xml:id="echoid-s7500" xml:space="preserve">qui étant <lb/>ajoûtées avec le poids de la charpente, l’on aura 4095 liv. </s> <s xml:id="echoid-s7501" xml:space="preserve">pour la <lb/>péſanteur totale du Pont réüni au centre de gravité.</s> <s xml:id="echoid-s7502" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7503" xml:space="preserve">Préſentement, il ſera aiſé de connoître la péſanteur des poids de <lb/>baſcule; </s> <s xml:id="echoid-s7504" xml:space="preserve">car l’on ſait que la péſanteur du Pont eſt à celle des poids <lb/>de baſcule dans l’état d’équilibre, comme la diagonale d’un quarrè <lb/>eſt au côté du même quarré, ou, ce qui revient au même, comme le ſi- <pb o="46" file="0344" n="362" rhead="LA SCIENCE DES INGENIEURS,"/> nus de l’angle droit eſt à celui de 45 degrés, ainſi on dira ſi 100000 <lb/>donnent 70710, que donneront 4095 liv. </s> <s xml:id="echoid-s7505" xml:space="preserve">péſanteur du Pont pour <lb/>celle des poids, que l’on trouvera de 2895 liv. </s> <s xml:id="echoid-s7506" xml:space="preserve">dont la moitié qui eſt <lb/>1447, ſerala péſanteur que doit avoir chaque poids; </s> <s xml:id="echoid-s7507" xml:space="preserve">mais comme <lb/>pour avoir égard au frotement, il vaut mieux les faire plus péſans <lb/>que trop légers, á cauſe qu’on ne peut pas les augmenter, au lieu <lb/>qu’il n’y a point d’inconvenient de ſurcharger le Pont s’il ſe trouvoit <lb/>au-deſſous de l’équilibre, il eſt à propos, en faveur de toutes ces <lb/>conſidérations, d’augmenter chaque poids de 100 liv. </s> <s xml:id="echoid-s7508" xml:space="preserve">c’eſt-à-dire de <lb/>lesfaire de 1547 liv. </s> <s xml:id="echoid-s7509" xml:space="preserve">au lieu de 1447. </s> <s xml:id="echoid-s7510" xml:space="preserve">Je n’ai pas dit que les poids de <lb/>baſcule devoient être cilindriques; </s> <s xml:id="echoid-s7511" xml:space="preserve">car l’on s’imagine bien qu’on ne <lb/>peut leur donner une figure qui convienne mieux pour rouler faci-<lb/>lement le long des couliſſes: </s> <s xml:id="echoid-s7512" xml:space="preserve">il s’agit donc de ſavoir qu’elle ſera la <lb/>valeur de l’axe de ces cilindres, ou celle du diamêtre de leur baſe, <lb/>qui eſt la même choſe; </s> <s xml:id="echoid-s7513" xml:space="preserve">car je ſupoſe ces deux lignes égales, afin <lb/>que les poids ayent moins de volume.</s> <s xml:id="echoid-s7514" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7515" xml:space="preserve">Sachant qu’un pied cube de fer péſe 580 liv. </s> <s xml:id="echoid-s7516" xml:space="preserve">commençons par <lb/>chercher quel eſt la péſanteur du cilindre qui ſeroit inſcrit dans un <lb/>pied cube: </s> <s xml:id="echoid-s7517" xml:space="preserve">pour cela, il faut remarquer que ces deux ſolides, ayant <lb/>la même hauteur, ſeront en même rai<unsure/>ſ<unsure/>on que leur baſe, par con-<lb/>ſéquent comme le quarré du diamêtre d’un cercle eſt à la ſuperficie <lb/>du même cercle, ou ſi l’on veut comme 14 eſt à 11; </s> <s xml:id="echoid-s7518" xml:space="preserve">il faut donc <lb/>dire, comme 14 eſt à 11, ainſi 580 péſanteur d’un pied cube defer, <lb/>eſt à celle du cilindre inſcrit, qu’on trouvera d’environ 456 liv.</s> <s xml:id="echoid-s7519" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7520" xml:space="preserve">Les cilindres ſemblables étant dans la raiſon des cubes de leur <lb/>axe, on pourra dire ſi un cilindre de 456. </s> <s xml:id="echoid-s7521" xml:space="preserve">liv. </s> <s xml:id="echoid-s7522" xml:space="preserve">dont le diamêtre de la <lb/>baſe & </s> <s xml:id="echoid-s7523" xml:space="preserve">l’axe ſont chacun d’un pied, donne 1728 pouces pour le <lb/>cube de ſon axe; </s> <s xml:id="echoid-s7524" xml:space="preserve">combien donnera 1547 liv. </s> <s xml:id="echoid-s7525" xml:space="preserve">péſanteur d’un autre <lb/>cilindre ſemblable au précédent pour le cube de ſon axe, on trou-<lb/>vera 5862 pouces, dont extrayant la racine cube, elle ſera de 18 <lb/>pouces qui eſt la valeur de l’axe que l’on demande; </s> <s xml:id="echoid-s7526" xml:space="preserve">il n’y a donc <lb/>pas de difficulté à avoir les poids de baſcule dans la juſte proportion <lb/>qui leur convient, puiſqu’on n’a qu’à demander aux Forges où l’on <lb/>coule le fer, deux poids péſants chacun 1547 liv. </s> <s xml:id="echoid-s7527" xml:space="preserve">dès qu’on leur <lb/>donnera pour baſe un cercle de 18 pouces de diamêtre, & </s> <s xml:id="echoid-s7528" xml:space="preserve">pour axe <lb/>une ligne égale à ce diamêtre.</s> <s xml:id="echoid-s7529" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7530" xml:space="preserve">J’ajoûterai que ces poids doiventêtre percés dans le milieu par un <lb/>trou d’un pouce en quarré, afin qu’on puiſſe y paſſer un eſſieu qui ſer-<lb/>ve à entretenir la chape qui doit en faciliter le mouvement le long <lb/>des couliſſes. </s> <s xml:id="echoid-s7531" xml:space="preserve">Cette chape eſt figurée ſur la planche où elle accom-<lb/>pagne le poids qui eſt déſigné par la Lettre V: </s> <s xml:id="echoid-s7532" xml:space="preserve">ſi je dis qu’il faut faire <pb o="47" file="0345" n="363" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> cet eſſieu quarré plûtôt que rond, c’eſt qu’il me ſemble que pour <lb/>diminuer le frotement, il vaut mieux que les extrêmités de l’eſſieu <lb/>étant arrondies tournent avec le poids dans la chape, que ſi le <lb/>poids tournoit autour de l’eſſieu.</s> <s xml:id="echoid-s7533" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7534" xml:space="preserve">Les couliſſes ſeront conſtruites de pierres de taille les plus dures <lb/>que l’on pourra trouver, leur longueur doit être de 4 pieds & </s> <s xml:id="echoid-s7535" xml:space="preserve">demi <lb/>ou 5 pieds & </s> <s xml:id="echoid-s7536" xml:space="preserve">leur largeur de 18 pouces ſur autant d’épaiſſeur, les <lb/>couliſſes y ſeront creuſées d’environ 6 ou 7 pouces de proſondeur <lb/>terminées par 2 bordures de 8 pouces d’épaiſſeur, pour entretenir <lb/>le poids & </s> <s xml:id="echoid-s7537" xml:space="preserve">les obliger à faire toûjours le même chemin.</s> <s xml:id="echoid-s7538" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7539" xml:space="preserve">Dans le fond de chaque couliſſe on y mettra deux barres de fer <lb/>plattes qui feront la même courbure que la Sinuſoide; </s> <s xml:id="echoid-s7540" xml:space="preserve">c’eſt ſur ces <lb/>barres que rouleront les poids afin de diminuer le frotement qui ſera <lb/>bien moins conſidérable, que ſila ſurface des cilindres touchoit par <lb/>tout en roulant: </s> <s xml:id="echoid-s7541" xml:space="preserve">d’ailleurs, ces barres ſerviront encore à empêcher <lb/>que le frotement n’uſe la pierre; </s> <s xml:id="echoid-s7542" xml:space="preserve">&</s> <s xml:id="echoid-s7543" xml:space="preserve">, pour que les poids ne la touchent <lb/>en aucun endroit, il eſt également néceſſaire d’apliquer des bandes <lb/>de fer contre les bords des couliſſes, le long deſquelles les deux <lb/>cercles ou baſes de chaque cilindre puiſſent gliſſer ſans jamais s’ac-<lb/>crocher, & </s> <s xml:id="echoid-s7544" xml:space="preserve">il ſuſſir<unsure/>a qu’entre l’un & </s> <s xml:id="echoid-s7545" xml:space="preserve">l’autre il y ait 2 ou 3 lignes de <lb/>jeu afin que le poids roule toûjours dans le même eſpace ſans qu’il <lb/>puiſſe s’écarter d’aucun côté. </s> <s xml:id="echoid-s7546" xml:space="preserve">Supoſant donc que les barres quiſeront <lb/>apliquées contre les bordures ayent chacune 3 lignes d’épaiſſeur cela <lb/>fera 6 lignes pour les deux, leſquelles étant ajoutées avec l’axe du <lb/>poids de baſcule, c’eſt-à-dire avec 18 pouces, ou ſi l’on veut avec <lb/>18 pouces 4 lignes, en y comprenant 4 lignes qu’il faudra donner <lb/>pour le jeu des poids, on aura 18 pouces 10 lignes, qui eſt exacte-<lb/>ment la largeur que les couliſſes doivent avoir: </s> <s xml:id="echoid-s7547" xml:space="preserve">ainſi, de quelque <lb/>péſanteur que ſoient les poids, dès qu’on en connoîtra l’axe, on ſaura <lb/>au juſte (en prenant garde à toutes ces petites circonſtances) la <lb/>largeur dans œuvre qu’il faudra donner aux couliſſes.</s> <s xml:id="echoid-s7548" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7549" xml:space="preserve">Donnant 18 pouces 10 lignes de largeur aux couliſſes, & </s> <s xml:id="echoid-s7550" xml:space="preserve">8 pou-<lb/>ces d’épaiſſeur à chaque bordure, cela fait environ 3 pieds en tout, <lb/>qui étant pris ſur la longueur de 4 pieds & </s> <s xml:id="echoid-s7551" xml:space="preserve">demi ou 5 pieds que doi-<lb/>vent avoir les pierres qui ſerviront à la conſtruction des couliſſes, <lb/>il reſtera un bout d’un pied & </s> <s xml:id="echoid-s7552" xml:space="preserve">demi ou deux pieds, qui doit être <lb/>engagé avec la maçonnerie des piés-droits contre leſquels les cou-<lb/>liſſes ſeront adoſſées, cette précaution étant néceſſaire pour rendre <lb/>l’ouvrage plus ſolide. </s> <s xml:id="echoid-s7553" xml:space="preserve">Il conviendroit même d’avoir des pierres de <lb/>deux ſortes de longueur, les unes de 5 pieds, les autres de 5 & </s> <s xml:id="echoid-s7554" xml:space="preserve"><lb/>demi, afin de les engager alternativement de 2 pieds & </s> <s xml:id="echoid-s7555" xml:space="preserve">de 2 pieds <pb o="48" file="0346" n="364" rhead="LA SCIENCE DES INGENIEURS,"/> & </s> <s xml:id="echoid-s7556" xml:space="preserve">demi: </s> <s xml:id="echoid-s7557" xml:space="preserve">à l’égard des autres bouts qui paroîtront en dehors, il <lb/>faut qu’ils ſoient bien maçonnés les uns contre les autres & </s> <s xml:id="echoid-s7558" xml:space="preserve">cram-<lb/>ponez avec des crampons de fer coulés en plomb, obſervant de <lb/>poſer des crochets de 2 pieds en 2 pieds dans les joints des pierres <lb/>au-deſſus des bordures de chaque couliſſe, enſorte que ces crochets <lb/>ſe répondent, afin que quand il y aura quelque réparation à faire <lb/>aux couliſſes, aux poids de baſcule, aux chaînes, ou aux poulies, <lb/>on puiſſe en poſant des planches ſur ces crochets, donner la faci-<lb/>lité aux ouvriers de monter & </s> <s xml:id="echoid-s7559" xml:space="preserve">de deſcendre le long des couliſſes.</s> <s xml:id="echoid-s7560" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7561" xml:space="preserve">Pour conſtruire les couliſſes de maniere qu’elles forment une <lb/>courbure qui ſoit exactement celle de la Sinuſoide, j’ajoûterai qu’il <lb/>faut tracer cette courbe en grand & </s> <s xml:id="echoid-s7562" xml:space="preserve">en faire 2 épures ou patrons <lb/>avec des planches; </s> <s xml:id="echoid-s7563" xml:space="preserve">dont l’un repréſente la convexité de la Sinuſoide, <lb/>& </s> <s xml:id="echoid-s7564" xml:space="preserve">l’autre ſa concavité; </s> <s xml:id="echoid-s7565" xml:space="preserve">ce dernier eſt abſolument neceſſaire aux ou-<lb/>vriers, pour les conduire dans la coupe des pierres, & </s> <s xml:id="echoid-s7566" xml:space="preserve">pour les aider <lb/>à les mettre en œuvre dans leur véritable ſituation.</s> <s xml:id="echoid-s7567" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7568" xml:space="preserve">Il eſt néceſſaire que les niches ſoient fermées par des cloiſons de <lb/>madriers, afin que perſonne n’y touche; </s> <s xml:id="echoid-s7569" xml:space="preserve">il ſuffira ſeulement d’y pra-<lb/>tiquer une petite porte pour y entrer quand on le jugera à propos: <lb/></s> <s xml:id="echoid-s7570" xml:space="preserve">ainſi le paſſage de la porte ſera comme à l’ordinaire, ſans qu’on voye <lb/>rien de tout ce qui contribuera à donner le mouvement au Pont.</s> <s xml:id="echoid-s7571" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7572" xml:space="preserve">Je crois en avoir dit aſſés pour rendre ſenſible l’execution du <lb/>Pont que je viens de décrire: </s> <s xml:id="echoid-s7573" xml:space="preserve">je laiſſe aux habiles gens qui vou-<lb/>dront le mettre en uſage d’y faire les changemens qu’ils jugeront <lb/>à propos; </s> <s xml:id="echoid-s7574" xml:space="preserve">mais, comme tout ce qui a un air de nouveauté ne man-<lb/>que pas de rencontrer des cenſeurs, qui ſe font un plaiſir de trou-<lb/>ver des difficultés par-tout, dans les choſes même les plus naturel-<lb/>les, on ſaura que peu de tems après avoir imaginé ce Pont, je l’ai fait <lb/>executer à un Château dans le voiſinage de la Fere, & </s> <s xml:id="echoid-s7575" xml:space="preserve">que j’y ay <lb/>ſuivi à peu de choſe près tout ce qui vient d’être détaillé.</s> <s xml:id="echoid-s7576" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7577" xml:space="preserve">On fait auſſi des Ponts-Levis aux ouvrages de dehors, comme <lb/> <anchor type="note" xlink:label="note-0346-01a" xlink:href="note-0346-01"/> demi-Lunes, ouvrages à corne, &</s> <s xml:id="echoid-s7578" xml:space="preserve">c. </s> <s xml:id="echoid-s7579" xml:space="preserve">pour en fermer l’entrée: </s> <s xml:id="echoid-s7580" xml:space="preserve">on les <lb/>leve par le moyen des baſcules à flêches, parce que n’étant pas né-<lb/>ceſſaire de couvrir avec des frontons les portes de ces ſortes de <lb/>paſſages, on n’aprehende point d’en couper l’Architecture, il ſuffit <lb/>que l’entrée ſoit décorée par des Pilaſtres couronnés d’un entable-<lb/>ment, comme on le peut voir dans les 3 premieres Figures de la <lb/>Planche 19. </s> <s xml:id="echoid-s7581" xml:space="preserve">qui conviennent fort quand les ouvrages détachés ſont <lb/>revêtus de maçonnerie juſqu’au parapet; </s> <s xml:id="echoid-s7582" xml:space="preserve">mais, quand ils ne le ſont <lb/>qu’à demi, alors il eſt aſſés inutile d’y faire aucune décoration, on <lb/>peut ſe contenter de faire porter la baſcule par un chaſſis qui doit <pb file="0347" n="365"/> <pb file="0347a" n="366"/> <anchor type="figure" xlink:label="fig-0347a-01a" xlink:href="fig-0347a-01"/> <pb file="0348" n="367"/> <pb o="49" file="0349" n="368" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> être ſitué ſur la berme, comme je l’ai exprimé dans la quatriéme & </s> <s xml:id="echoid-s7583" xml:space="preserve"><lb/>cinquiéme Figure de la même Planche, que je ne m’amuſerai point <lb/>à expliquer, parce qu’elle ne contient rien qui ne ſoit facile à <lb/>concevoir.</s> <s xml:id="echoid-s7584" xml:space="preserve"/> </p> <div xml:id="echoid-div340" type="float" level="3" n="1"> <note position="left" xlink:label="note-0346-01" xlink:href="note-0346-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>19.</note> <figure xlink:label="fig-0347a-01" xlink:href="fig-0347a-01a"> <image file="0347a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0347a-01"/> </figure> </div> </div> <div xml:id="echoid-div342" type="section" level="2" n="118"> <head xml:id="echoid-head266" xml:space="preserve">CHAPITRE SIXIE’ME.</head> <head xml:id="echoid-head267" style="it" xml:space="preserve">Des Ponts dormans qui ſervent à faciliter l’Entrée des Villes <lb/>de Guerre.</head> <p> <s xml:id="echoid-s7585" xml:space="preserve">LEs Ponts dormans, que l’on fait pour paſſer les Foſſés des For-<lb/>tifications, ſont toûjours de charpente, & </s> <s xml:id="echoid-s7586" xml:space="preserve">élevés ſur pluſieurs <lb/>chevalets quiſont poſés ſur des Piles de Maçonnerie A, dont la hau-<lb/>teur ſe régle ſur la profondeur du Foſſé: </s> <s xml:id="echoid-s7587" xml:space="preserve">quelquefois dans les lieux <lb/>marécageux, où on ne peut fonder des piles de Maçonnerie ſans <lb/>beaucoup de difficulté & </s> <s xml:id="echoid-s7588" xml:space="preserve">de grandes dépenſes, on ſe contente de <lb/>planter des files de pieux d’une longueur ſuffiſante, pour qu’une <lb/>partie étant enfoncée à refus de mouton, l’autre qui reſte en dehors <lb/>ſoit aſſés élevée pour recevoir les chapeaux qui doivent être à peu <lb/>près au niveau du rez-de-Chauſſée.</s> <s xml:id="echoid-s7589" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7590" xml:space="preserve">Quand on n’a point de bois d’une aſſés belle longueur, on en-<lb/> <anchor type="note" xlink:label="note-0349-01a" xlink:href="note-0349-01"/> fonce autant de files de pilots qu’on le juge neceſſaire, par raport <lb/>au nombre des travées que doit avoir le Pont: </s> <s xml:id="echoid-s7591" xml:space="preserve">ces pilots ſont arra-<lb/>ſés au niveau du fonds du Foſſé par des tenons qui s’emmanchent <lb/>dans le ſole des chevalets. </s> <s xml:id="echoid-s7592" xml:space="preserve">C’eſt ainſi que j’ai vû conſtruire à St. </s> <s xml:id="echoid-s7593" xml:space="preserve">Ve-<lb/>nant en 1709. </s> <s xml:id="echoid-s7594" xml:space="preserve">celui qui eſt ſur le grand Foſſé de la Porte d’Aire.</s> <s xml:id="echoid-s7595" xml:space="preserve"/> </p> <div xml:id="echoid-div342" type="float" level="3" n="1"> <note position="right" xlink:label="note-0349-01" xlink:href="note-0349-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>20.</note> </div> <p> <s xml:id="echoid-s7596" xml:space="preserve">Le Pont, dont il eſt queſtion preſentement, eſt compoſé de plu-<lb/>ſieurs travées & </s> <s xml:id="echoid-s7597" xml:space="preserve">chevalets dont on ne détermine point ici la quan-<lb/>tité, parce que cela dépend de la longueur du Foſſé où il doit être <lb/>executé; </s> <s xml:id="echoid-s7598" xml:space="preserve">chaque Solle B, qui ne porte point de baſcule, a 22 pieds <lb/>de longueur ſur 10 à 12 de groſſeur; </s> <s xml:id="echoid-s7599" xml:space="preserve">celui C, qui porte le chaſſis <lb/>de la baſcule a 25 pieds de longueur ſur 12 à 12 pouces de groſ-<lb/>ſeur; </s> <s xml:id="echoid-s7600" xml:space="preserve">ſur chacune de ces ſoles, qui ne portent point de baſcule, ſont <lb/>aſſemblés à tenons & </s> <s xml:id="echoid-s7601" xml:space="preserve">mortoiſes 5 Poteaux D, avec deux Liens bou-<lb/>tans H, terminés d’un Chapeau E.</s> <s xml:id="echoid-s7602" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7603" xml:space="preserve">Les poteaux ont 11 à 12 pouces de groſſeur ſur differentes lon-<lb/>gueurs, ſuivant les endroits où ils ſont employés.</s> <s xml:id="echoid-s7604" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7605" xml:space="preserve">Le chevalet, qui porte la baſcule du Pont-Levis, eſt conſtruit de <lb/>même, avec cette difference qu’il y a deux poteaux de plus, & </s> <s xml:id="echoid-s7606" xml:space="preserve">que les <pb o="50" file="0350" n="369" rhead="LA SCIENCE DES INGENIEURS,"/> chapeaux ont 25 pieds de longueur ſur 13 à 14 pouces de groſ-<lb/>ſeur.</s> <s xml:id="echoid-s7607" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7608" xml:space="preserve">Sur tous les chapeaux E, il y a, d’un chevalet a l’autre, cinq cours <lb/>de longerons F, de 11 à 12 pouces de groſſeur, eſpacés entr’eux de <lb/>diſtance égale, formant en tout une largeur de 14 pieds, & </s> <s xml:id="echoid-s7609" xml:space="preserve">ſont re-<lb/>couverts d’un Plancher de madriers I, de 4 pouces d’épaiſſeur, che-<lb/>villés ſur chaque longeron d’une broche de fer de 8 à 9 pouces <lb/>de longueur, ébarbellée par les angles.</s> <s xml:id="echoid-s7610" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7611" xml:space="preserve">Sur ce premier plancher l’on en poſe un ſecond de 8 pieds de <lb/>largeur ſeulement, & </s> <s xml:id="echoid-s7612" xml:space="preserve">de 3 pouces d’épaiſſeur, qu’on apelle redouble-<lb/>ment, ſur lequel l’on attache quelque fois des barres de fer plattes <lb/>autant plain que vuide, & </s> <s xml:id="echoid-s7613" xml:space="preserve">de même longueur que les madriers.</s> <s xml:id="echoid-s7614" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7615" xml:space="preserve">L’on n’employe plus guére de redoublement, ni de barres de fer, <lb/>pour conſerver les Ponts dormans: </s> <s xml:id="echoid-s7616" xml:space="preserve">on les couvre d’un pavé plus <lb/>élevé dans le milieu qu’aux extrêmités pour l’écoulement des eaux; <lb/></s> <s xml:id="echoid-s7617" xml:space="preserve">& </s> <s xml:id="echoid-s7618" xml:space="preserve">alors l’on poſe le long des poteaux montans des gardes-pavé, de 9 <lb/>à 11 pouces d’équarriſſage. </s> <s xml:id="echoid-s7619" xml:space="preserve">Il eſt certain que ce pavé rend le Pont <lb/>d’une bien plus longue durée, les réparations n’en étant pas ſi fré-<lb/>quentes qu’aux autres.</s> <s xml:id="echoid-s7620" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7621" xml:space="preserve">A l’extrêmité de la largeur du premier plancher, & </s> <s xml:id="echoid-s7622" xml:space="preserve">ſur les cha-<lb/>peaux E, l’on aſſemble à tenons & </s> <s xml:id="echoid-s7623" xml:space="preserve">mortoiſes les Poteaux montans G, <lb/>des gardes-foux de 7 pieds & </s> <s xml:id="echoid-s7624" xml:space="preserve">demi de longueur compris les tenons <lb/>ſur 8 à 8 pouces de groſſeur, terminez par une tête arrondie ou à pan <lb/>avec une gorge & </s> <s xml:id="echoid-s7625" xml:space="preserve">un quart de rond au-deſſous, comme il eſt figuré <lb/>au deſſein: </s> <s xml:id="echoid-s7626" xml:space="preserve">ces poteaux ſont affermis chacun d’un lien pendant M, <lb/>de 6 pieds de longueur ſur 12 à 6 pouces d’épaiſſeur, chamfrines à <lb/>un pied au-deſſus du chapeau par un talon renverſé, qui reduit la <lb/>partie ſupérieure à 8 pouces de largeur pour affleurer le poteau des <lb/>gardes-foux; </s> <s xml:id="echoid-s7627" xml:space="preserve">ces poteaux ſont liés enſemble par deux cours de liſſes, <lb/>L & </s> <s xml:id="echoid-s7628" xml:space="preserve">K, dont la premiere L eſt appellée liſſe d’apuy.</s> <s xml:id="echoid-s7629" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7630" xml:space="preserve">Le chaſſis de la baſcule eſt compoſé de deux poteaux montans N, <lb/>de 8 liens enguette O, d’un chapeau P, de 4 liens ceintrés Q, de deux <lb/>liens heurtoirs R, & </s> <s xml:id="echoid-s7631" xml:space="preserve">de 2 ſemeles S; </s> <s xml:id="echoid-s7632" xml:space="preserve">les poteaux montans N, ont 14 pieds <lb/>de longueur ſur 13 à 14 pouces de groſſeur élevés à plomb em-<lb/>mortoiſés dans le chapeau E, ſur lequel ils ſont aſſemblés par les 4 <lb/>liens enguette O, & </s> <s xml:id="echoid-s7633" xml:space="preserve">arcboutés par les 4 autres qui ſont aſſemblés dans <lb/>les ſemeles S: </s> <s xml:id="echoid-s7634" xml:space="preserve">ces 8 liens enguette ont 10 ſur 12 d’épaiſſeur, & </s> <s xml:id="echoid-s7635" xml:space="preserve">de <lb/>differentes longueurs, ſuivant les endroits où ils ſont employés; </s> <s xml:id="echoid-s7636" xml:space="preserve">il <lb/>faut ſeulement remarquer, qu’ils doivent faire avec le chapeau & </s> <s xml:id="echoid-s7637" xml:space="preserve">la <lb/>ſemelle où ils ſont aſſemblés un angle d’environ 60 dégrés.</s> <s xml:id="echoid-s7638" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7639" xml:space="preserve">La baſcule eſt compoſée de deux flêches T, d’une culaſſe V, de deux <pb file="0351" n="370"/> <pb file="0351a" n="371"/> <anchor type="figure" xlink:label="fig-0351a-01a" xlink:href="fig-0351a-01"/> <pb file="0352" n="372"/> <pb o="51" file="0353" n="373" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> entre-toiſes X & </s> <s xml:id="echoid-s7640" xml:space="preserve">r, dont la derniere r, s’apelle entre-toiſe des tou-<lb/>rillons, & </s> <s xml:id="echoid-s7641" xml:space="preserve">qui doit être comme la culaſſe aſſemblée dans les flêches <lb/>par un double tenon: </s> <s xml:id="echoid-s7642" xml:space="preserve">l’on fortifie cet aſſemblage ordinairement <lb/>par des Croix de St. </s> <s xml:id="echoid-s7643" xml:space="preserve">André Z, & </s> <s xml:id="echoid-s7644" xml:space="preserve">d’autres liens, tant pour la ſolidité <lb/>de l’ouvrage, que pour donner du poids à la baſcule & </s> <s xml:id="echoid-s7645" xml:space="preserve">faire un <lb/>équilibre à peu-près égal au Pont-Levis; </s> <s xml:id="echoid-s7646" xml:space="preserve">je dis à peu-près, parce <lb/>qu’il faut que la baſcule ſoit au moins de 200 liv. </s> <s xml:id="echoid-s7647" xml:space="preserve">plus légere que <lb/>le tablier.</s> <s xml:id="echoid-s7648" xml:space="preserve"/> </p> <div xml:id="echoid-div343" type="float" level="3" n="2"> <figure xlink:label="fig-0351a-01" xlink:href="fig-0351a-01a"> <image file="0351a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0351a-01"/> </figure> </div> <p> <s xml:id="echoid-s7649" xml:space="preserve">Les flêches ont 14 à 16 pouces de groſſeur à la culaſſe revenant <lb/>à 10 à 12 aux extrêmités, dont la partie qui excede l’entre-toiſe <lb/>des tourillons r, eſt preſque toûjours taillée à 8 pans: </s> <s xml:id="echoid-s7650" xml:space="preserve">la culaſſe a <lb/>auſſi 14 à 16 pouces de groſſeur, & </s> <s xml:id="echoid-s7651" xml:space="preserve">les deux autres entre-toiſes X <lb/>& </s> <s xml:id="echoid-s7652" xml:space="preserve">r, un peu moins, c’eſt-à-dire, qu’elles affleurent toûjours la <lb/>groſſeur des flêches; </s> <s xml:id="echoid-s7653" xml:space="preserve">à l’égard des Croix de St. </s> <s xml:id="echoid-s7654" xml:space="preserve">André & </s> <s xml:id="echoid-s7655" xml:space="preserve">des autres <lb/>liens, ils ſont d’un ou même de 2 pouces plus petits, ſuivant que <lb/>l’on a beſoin de poids pour l’équilibre.</s> <s xml:id="echoid-s7656" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7657" xml:space="preserve">Le tablier des Ponts-Levis eſt ordinairement compoſé d’une piéce <lb/>qui porte les tourillons de 10 pieds de longueur ſur 10 à 10 pouces <lb/>de groſſeur, d’une autre h, apellée chevet, & </s> <s xml:id="echoid-s7658" xml:space="preserve">de 6 ſoliveaux j, de <lb/>12 pieds de longueur ſur 5 à 6 pouces de groſſeur, recouverts de <lb/>madriers de 2 pouces, & </s> <s xml:id="echoid-s7659" xml:space="preserve">redoublés de barres de fer autant plain que <lb/>vuide.</s> <s xml:id="echoid-s7660" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7661" xml:space="preserve">Il y a des Ingenieurs, qui donnent quelques pouces moins en <lb/>quarré au chevet qu’à la piéce des tourillons, & </s> <s xml:id="echoid-s7662" xml:space="preserve">ne donnent pas <lb/>tant de groſſeur non plus au bout des ſoliveaux qui répondent au <lb/>chevet; </s> <s xml:id="echoid-s7663" xml:space="preserve">afin que le centre de gravité du tablier, n’étant point dans <lb/>le milieu de ſa longueur, mais plus près de la piéce des tourillons que <lb/>du chevet, la baſcule ſoit moins chargée & </s> <s xml:id="echoid-s7664" xml:space="preserve">rende le mouvement <lb/>du Pont plus doux: </s> <s xml:id="echoid-s7665" xml:space="preserve">c’eſt en effet ce qui arrive quand on en <lb/>uſe ainſi.</s> <s xml:id="echoid-s7666" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7667" xml:space="preserve">L’on fait, à la tête des Ponts dormans, une barriere ſur le penul-<lb/>tiéme chevalet, dont les poteaux ſont comme ceux du chaſſis de la <lb/>baſcule des Ponts-Levis aſſemblés ſur le chapeau du chevalet & </s> <s xml:id="echoid-s7668" xml:space="preserve">affer-<lb/>mis par deux liens pendans a, & </s> <s xml:id="echoid-s7669" xml:space="preserve">deux autres liens b, plus quatre au-<lb/>tres liens enguette ſur l’interieur des poteaux ſemblables à ceux <lb/>des baſcules O, & </s> <s xml:id="echoid-s7670" xml:space="preserve">qui ne ſont pas figurés ſur le deſſein.</s> <s xml:id="echoid-s7671" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7672" xml:space="preserve">La barriere eſt aſſemblée à claire voye à 2 vantaux, chacun com-<lb/>poſé d’un tournant c, d’un battant d, & </s> <s xml:id="echoid-s7673" xml:space="preserve">de 5 à 6 épées ou barreauxe, <lb/>avec une barre & </s> <s xml:id="echoid-s7674" xml:space="preserve">deux traverſes, le tout de même hauteur: </s> <s xml:id="echoid-s7675" xml:space="preserve">les tour-<lb/>nans & </s> <s xml:id="echoid-s7676" xml:space="preserve">battans c, & </s> <s xml:id="echoid-s7677" xml:space="preserve">d, ont 7 pieds de hauteur ſur 5 à 7 pouces <lb/>de groſſeur; </s> <s xml:id="echoid-s7678" xml:space="preserve">les barres & </s> <s xml:id="echoid-s7679" xml:space="preserve">traverſes ont les mêmes groſſeurs; </s> <s xml:id="echoid-s7680" xml:space="preserve">& </s> <s xml:id="echoid-s7681" xml:space="preserve">les <pb o="52" file="0354" n="374" rhead="LA SCIENCE DES INGENIEURS,"/> barreaux f, tant de la barriere que des aîles, ont 3 à 4 pouces <lb/>de groſſeur, poſés tant plain que vuide, & </s> <s xml:id="echoid-s7682" xml:space="preserve">entaillés moitié par moitié <lb/>dans les barres & </s> <s xml:id="echoid-s7683" xml:space="preserve">traverſes qui ſont aſſemblées à tenons & </s> <s xml:id="echoid-s7684" xml:space="preserve">mor-<lb/>toiſes dans les tournans & </s> <s xml:id="echoid-s7685" xml:space="preserve">batans de la barriere.</s> <s xml:id="echoid-s7686" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7687" xml:space="preserve">Il ſe fait auſſi des barrieres, pour fermer la ſortie du chemin cou-<lb/>vert des portes, auſſi-bien que les places d’Armes qui ſont répan-<lb/>duës dans les dehors; </s> <s xml:id="echoid-s7688" xml:space="preserve">on en peut voir ici l’élevation. </s> <s xml:id="echoid-s7689" xml:space="preserve">Cette barriere <lb/>a 2 ventaux qui tournent ſur des pivots & </s> <s xml:id="echoid-s7690" xml:space="preserve">arrêtés par le haut avec <lb/>des collets de fer aux poteaux qui ſervent à l’entretenir; </s> <s xml:id="echoid-s7691" xml:space="preserve">ces poteaux <lb/>ont 9 pieds & </s> <s xml:id="echoid-s7692" xml:space="preserve">demi de longueur, & </s> <s xml:id="echoid-s7693" xml:space="preserve">8 ſur 6 pouces de groſſeur, <lb/>tenus en raiſon par un patin de 7 pieds de long & </s> <s xml:id="echoid-s7694" xml:space="preserve">de 7 à 8 pouces <lb/>de gros, & </s> <s xml:id="echoid-s7695" xml:space="preserve">aſſemblés par 2 ſolles de 8 à 9 pouces de groſſeur, dont <lb/>l’un doit être enterré de 2 ou 3 pieds, & </s> <s xml:id="echoid-s7696" xml:space="preserve">l’autre poſé au niveau des <lb/>paſſages: </s> <s xml:id="echoid-s7697" xml:space="preserve">les 2 ventaux de la barriere ſont entretenus par des tra-<lb/>ver ſes & </s> <s xml:id="echoid-s7698" xml:space="preserve">contre-fiches de 6 ſur 7 pouces de gros, aſſemblés par entaille <lb/>avec les barrieres par une profondeur de moitié par moitié; </s> <s xml:id="echoid-s7699" xml:space="preserve">ces <lb/>barreaux doivent avoir 5 ſur 6 pouces de groſſeur & </s> <s xml:id="echoid-s7700" xml:space="preserve">apointés com-<lb/>me les palliſſades.</s> <s xml:id="echoid-s7701" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7702" xml:space="preserve">Quand l’eau du foſſé eſt dormante, ou qu’elle n’a qu’un cours <lb/>paiſible, les ponts ſe peuvent faire à peu-près ſemblables aux pré-<lb/>cedens; </s> <s xml:id="echoid-s7703" xml:space="preserve">mais, s’il ſe rencontroit une riviere à l’entrée de la place, <lb/>dont le courant fût rapide, il faudroit s’y prendre d’une façon tou-<lb/>te differente, comme on le va voir.</s> <s xml:id="echoid-s7704" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7705" xml:space="preserve">Les ponts dormans de charpente, qui ſervent au paſſage des ri-<lb/>vieres, ſont ordinairement conſtruits comme celui qui eſt répreſen-<lb/>té ſur la Planche 21: </s> <s xml:id="echoid-s7706" xml:space="preserve">mais de quelque façon que ſoit diſpoſé l’aſ-<lb/> <anchor type="note" xlink:label="note-0354-01a" xlink:href="note-0354-01"/> ſemblage de la charpente, on les éleve auſſi haut que la naviga-<lb/>tion le demande; </s> <s xml:id="echoid-s7707" xml:space="preserve">quant à leur largeur, elle doit être proportion-<lb/>née à la grandeur des routes: </s> <s xml:id="echoid-s7708" xml:space="preserve">on les éleve ſur pluſieurs palées, com-<lb/>poſées d’une ou deux files de pieux, & </s> <s xml:id="echoid-s7709" xml:space="preserve">l’on a ſoin de faire une de <lb/>leur travées aſſés large, pour que les plus grands bateaux puiſſent <lb/>y paſſer librement.</s> <s xml:id="echoid-s7710" xml:space="preserve"/> </p> <div xml:id="echoid-div344" type="float" level="3" n="3"> <note position="left" xlink:label="note-0354-01" xlink:href="note-0354-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>21.</note> </div> <p> <s xml:id="echoid-s7711" xml:space="preserve">Le nombre des pieux, qui compoſe chaque palée, eſt reglé <lb/>par la largeur du pont, & </s> <s xml:id="echoid-s7712" xml:space="preserve">l’on obſerve qu’ils ayent environ 3 pieds <lb/>de diſtance par en bas, qu’on réduit en haut à un pied & </s> <s xml:id="echoid-s7713" xml:space="preserve">demi, <lb/>ou à deux pieds pour chaque vuide d’entrevoux, parce qu’ainſi on <lb/>forme une maniere d’empatement qui reſiſte d’avantage aux efforts <lb/>de l’eau, que ſi tous les pieux étoient perpendiculaires.</s> <s xml:id="echoid-s7714" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7715" xml:space="preserve">Quand on ne fait les travées que d’une file de pieux ſeulement, <lb/>cela ne doit ſe pratiquer qu’aux ponts qui ſervent à traverſer de <lb/>petites rivieres; </s> <s xml:id="echoid-s7716" xml:space="preserve">car, pour ceux qui ſont ſur des rivieres fort <pb file="0355" n="375"/> <pb file="0355a" n="376"/> <anchor type="figure" xlink:label="fig-0355a-01a" xlink:href="fig-0355a-01"/> <pb file="0356" n="377"/> <pb o="53" file="0357" n="378" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> larges, & </s> <s xml:id="echoid-s7717" xml:space="preserve">dont le courant eſt rapide, les palées doivent être <lb/>faites de 2 ou 3 rangs de files de pieux bien coefés, liernés, & </s> <s xml:id="echoid-s7718" xml:space="preserve">moiſés, <lb/>avec des contre-fiches à deux rangs, pour les entretenir comme dans <lb/>la planche 22.</s> <s xml:id="echoid-s7719" xml:space="preserve"/> </p> <div xml:id="echoid-div345" type="float" level="3" n="4"> <figure xlink:label="fig-0355a-01" xlink:href="fig-0355a-01a"> <image file="0355a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0355a-01"/> </figure> </div> <p> <s xml:id="echoid-s7720" xml:space="preserve">La plûpart de ces palées ſont pour l’ordinaire contregar dées du cô-<lb/>té d’amont par un avant-bec de pilotage en forme de briſe-glace, qu’on <lb/> <anchor type="note" xlink:label="note-0357-01a" xlink:href="note-0357-01"/> revêtit de planches par dehors, depuis les plus baſſes eaux de la ri-<lb/>viere, juſqu’aux plus hautes des inondations, afin que lors que le <lb/>courant charie des glaces & </s> <s xml:id="echoid-s7721" xml:space="preserve">des arbres, les uns & </s> <s xml:id="echoid-s7722" xml:space="preserve">les autres ayent <lb/>moins de priſe ſur le corps des palées, & </s> <s xml:id="echoid-s7723" xml:space="preserve">qu’ils ne faſſent que <lb/>gliſſer.</s> <s xml:id="echoid-s7724" xml:space="preserve"/> </p> <div xml:id="echoid-div346" type="float" level="3" n="5"> <note position="right" xlink:label="note-0357-01" xlink:href="note-0357-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>22.</note> </div> <p> <s xml:id="echoid-s7725" xml:space="preserve">Comme il peut arriver qu’en voulant planter des pieux pour <lb/>former une palée, l’on rencontre du roc dans le lit de la riviere, <lb/>poſitivement dans l’endroit où l’on en veut enfoncer; </s> <s xml:id="echoid-s7726" xml:space="preserve">ſi l’on <lb/>n’a pû faire des batardaux & </s> <s xml:id="echoid-s7727" xml:space="preserve">les épuiſemens, enſorte qu’il reſte 5 <lb/>ou 6 pieds d’eau, on ſera ſans doute embaraſſé dans un pareil cas, <lb/>puiſqu’il n’eſt pas poſſible que des hommes tout couverts d’eau, <lb/>puiſſent faire un trou de 3 ou 4 pieds dans le roc: </s> <s xml:id="echoid-s7728" xml:space="preserve">pour ſurmon-<lb/>ter une pareille difficulté, il faut faire deux tonneaux ouverts par <lb/>les deux bouts, dont l’un ait 9 pieds de diamétre & </s> <s xml:id="echoid-s7729" xml:space="preserve">l’autre 5, & </s> <s xml:id="echoid-s7730" xml:space="preserve">que <lb/>ces deux tonneaux ſoient deux pieds plus hauts que la profondeur <lb/>de l’eau, l’on placera le plus grand dans la riviere à l’endroit où l’on <lb/>veut percer, de maniere que le roc ſe trouve dans le milieu du <lb/>tonneau, enſuite l’on enfoncera les douves de quelques pouces <lb/>dans le lit de la riviere, & </s> <s xml:id="echoid-s7731" xml:space="preserve">l’on chargera le deſſus du tonneau de <lb/>façon que le courant ne l’ébranle point, après l’on mettra le petit <lb/>tonneau dans le milieu du grand, & </s> <s xml:id="echoid-s7732" xml:space="preserve">l’on remplira de terre glaiſe <lb/>l’eſpace qui eſt entre deux, que l’on battra avec la demoiſelle, <lb/>pour qu’elle faſſe un bon maſſif; </s> <s xml:id="echoid-s7733" xml:space="preserve">enfin l’on vuidera l’eau qui ſera <lb/>dans le petit tonneau, & </s> <s xml:id="echoid-s7734" xml:space="preserve">l’on y introduira un ouvrier qui fera le trou <lb/>qu’on s’étoit propoſé.</s> <s xml:id="echoid-s7735" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7736" xml:space="preserve">Mais, pour revenir à notre pont de charpente de la Planche <lb/>21, je crois qu’il eſt inuile de m’étendre ſur l’aſſemblage des pie-<lb/>ces dont il eſt compoſé: </s> <s xml:id="echoid-s7737" xml:space="preserve">je raporterai ſeulement les dimenſions de <lb/>chacune; </s> <s xml:id="echoid-s7738" xml:space="preserve">les plans, profils, & </s> <s xml:id="echoid-s7739" xml:space="preserve">élevations, donneront l’intelligence <lb/>du reſte.</s> <s xml:id="echoid-s7740" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7741" xml:space="preserve">Les moiſes ſont de differentes longueurs, & </s> <s xml:id="echoid-s7742" xml:space="preserve">de 8 à 9 pouces de <lb/>groſſeur.</s> <s xml:id="echoid-s7743" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7744" xml:space="preserve">Les chapeaux ſont de 6 toiſes de longueur chacun, & </s> <s xml:id="echoid-s7745" xml:space="preserve">de 18 à <lb/>20 pouces de groſſeur.</s> <s xml:id="echoid-s7746" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7747" xml:space="preserve">Les ſemelles au-deſſus des chapeaux, ont chacune 16 pieds de <lb/>longueur & </s> <s xml:id="echoid-s7748" xml:space="preserve">15 pouces de groſſeur.</s> <s xml:id="echoid-s7749" xml:space="preserve"/> </p> <pb o="54" file="0358" n="379" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s7750" xml:space="preserve">Les liens ſous les ſemelles ont chacun 6 pieds de long, ſur 10 <lb/>à 12 pouces de groſſeur.</s> <s xml:id="echoid-s7751" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7752" xml:space="preserve">Les Poutrelles des travées du pont, qui ne ſont pas dans le grand <lb/>courant, ont ſix toiſes 4 pieds de longueur, ſur 14 à 15 pouces <lb/>de groſſeur; </s> <s xml:id="echoid-s7753" xml:space="preserve">& </s> <s xml:id="echoid-s7754" xml:space="preserve">celles du grand courant ont 7 toiſes 4 pieds & </s> <s xml:id="echoid-s7755" xml:space="preserve">de-<lb/>mi ſur 15 à 16 pouces de groſſeur.</s> <s xml:id="echoid-s7756" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7757" xml:space="preserve">Le plancher du pont a 5 toiſes 5 pieds de largeur, ſur 3 pouces <lb/>d’épaiſſeur.</s> <s xml:id="echoid-s7758" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7759" xml:space="preserve">Le redoublement du plancher entre les deux banquettes, a 3 <lb/>toiſes de largeur, ſur 2 pouces d’épaiſſeur.</s> <s xml:id="echoid-s7760" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7761" xml:space="preserve">Les ſeuilles des banquettes ſont de toute la longueur du pont, <lb/>& </s> <s xml:id="echoid-s7762" xml:space="preserve">de 20 pouces de groſſeur.</s> <s xml:id="echoid-s7763" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7764" xml:space="preserve">Les ſolivaux des banquettes ont 6 pieds de long, ſur 8 pouces <lb/>de groſſeur.</s> <s xml:id="echoid-s7765" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7766" xml:space="preserve">Le plancher des banquettes a 6 pieds de largeur, ſur 2 pouces <lb/>d’épaiſſeur.</s> <s xml:id="echoid-s7767" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7768" xml:space="preserve">Les poteaux des garde-ſoux ont 6. </s> <s xml:id="echoid-s7769" xml:space="preserve">pieds de long, ſur 8 & </s> <s xml:id="echoid-s7770" xml:space="preserve">10 <lb/>pouces de groſſeur.</s> <s xml:id="echoid-s7771" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7772" xml:space="preserve">Les liens pendans ont 10 pieds de longueur, ſur 10 pouces par <lb/>le bout, & </s> <s xml:id="echoid-s7773" xml:space="preserve">20 ſur le bout du chapeau.</s> <s xml:id="echoid-s7774" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7775" xml:space="preserve">Les décharges ou jettées ont chacune 20 pieds de longueur, ſur <lb/>8 à 9 pouces de groſſeur.</s> <s xml:id="echoid-s7776" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7777" xml:space="preserve">Les garde-foux ont 7 à 8 pouces de groſſeur.</s> <s xml:id="echoid-s7778" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7779" xml:space="preserve">Quant aux briſe-glaces, les pilots ſont de differentes longueurs, <lb/>ſur 13 à 19 pouces de groſſeur.</s> <s xml:id="echoid-s7780" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7781" xml:space="preserve">Les moiſes ſont auſſi de differentes longueurs, & </s> <s xml:id="echoid-s7782" xml:space="preserve">ont 8 à 10 pou-<lb/>ces de groſſeur.</s> <s xml:id="echoid-s7783" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7784" xml:space="preserve">Il ſe fait des ponts tournans qui ſont très commodes, pour faci-<lb/>liter le paſſage au-deſſus des écluſes, ou aux autres endroits d’une <lb/>riviere ou canal, où il doit paſſer des batteaux: </s> <s xml:id="echoid-s7785" xml:space="preserve">je ne m’étois pas <lb/>propoſé de parler ici de ces ſortes de ponts, parce qu’étant rela-<lb/>tifs aux écluſes, ils apartiennent plûtôt à l’Architecture Hydrauli-<lb/>que, qu’à la matiere que je traite preſentement; </s> <s xml:id="echoid-s7786" xml:space="preserve">mais comme, ſans <lb/>y faire attention, on en a raporté deux deſſeins ſur la Planche 21, <lb/>je me trouve dans la neceſſité d’en donner l’Explication, quoi <lb/>qu’aſſés hors de propos par raport au plan que je me ſuis fait, de <lb/>ne parler de chaque choſe que dans l’endroit qui lui convient na-<lb/>turellement.</s> <s xml:id="echoid-s7787" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7788" xml:space="preserve">Le plan CI du premier Pont fait voir, qu’il eſt coupé en deux <lb/> <anchor type="note" xlink:label="note-0358-01a" xlink:href="note-0358-01"/> également, afin que chaque moitié ſe puiſe ſeparer, & </s> <s xml:id="echoid-s7789" xml:space="preserve">ſe rejoin-<lb/>dre, en tournant comme ſur un pivot: </s> <s xml:id="echoid-s7790" xml:space="preserve">une de ces moitiés eſt re- <pb file="0359" n="380"/> <pb file="0359a" n="381"/> <anchor type="figure" xlink:label="fig-0359a-01a" xlink:href="fig-0359a-01"/> <pb file="0360" n="382"/> <pb o="55" file="0361" n="383" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> preſentée à jour, pour montrer l’aſſemblage de la charpente, & </s> <s xml:id="echoid-s7791" xml:space="preserve"><lb/>l’autre eſt recouverte de madriers; </s> <s xml:id="echoid-s7792" xml:space="preserve">l’on obſervera que la jonction <lb/>des deux moitiés ſe fait en portion de cercle à l’endroit AA, afin <lb/>qu’étant arrêtée par des verroux, l’union en ſoit plus ferme: </s> <s xml:id="echoid-s7793" xml:space="preserve">à l’é-<lb/>gard de l’élevation elle n’a rien de particulier, ſinon que les gar-<lb/>des-foux ſont de fer, pour que le pont en paroiſſe plus leger.</s> <s xml:id="echoid-s7794" xml:space="preserve"/> </p> <div xml:id="echoid-div347" type="float" level="3" n="6"> <note position="left" xlink:label="note-0358-01" xlink:href="note-0358-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>21.</note> <figure xlink:label="fig-0359a-01" xlink:href="fig-0359a-01a"> <image file="0359a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0359a-01"/> </figure> </div> <p> <s xml:id="echoid-s7795" xml:space="preserve">L’autre deſſein repreſente encore un pont tournant, dont la jonc-<lb/>tion ſe ſait obliquement à l’endroit D: </s> <s xml:id="echoid-s7796" xml:space="preserve">le plan eſt à peu près de <lb/>même que le précédent, il n’y a de difference que dans l’élevation, <lb/>où les gardes-foux, au lieu d’être de fer ſont de bois, d’un aſſembla-<lb/>ge particulier qu’il ſuffit d’examiner pour voir que l’on a eu en <lb/>vûë de rendre ce pont beaucoup plus ſolide que l’autre; </s> <s xml:id="echoid-s7797" xml:space="preserve">& </s> <s xml:id="echoid-s7798" xml:space="preserve">com-<lb/>me une pareille conſtruction chargeroit beaucoup la crapaudine, on <lb/>a crû que pour la ſoulager il falloit faire des roulettes à l’entour, <lb/>afin de faire tourner le pont aiſément, & </s> <s xml:id="echoid-s7799" xml:space="preserve">qu’il demeure toûjours <lb/>en équilibre, ſans pancher plus d’un côté que de l’autre: </s> <s xml:id="echoid-s7800" xml:space="preserve">à l’égard <lb/>des dimenſions du pont de la 22. </s> <s xml:id="echoid-s7801" xml:space="preserve">Planche, je n’en parlerai pas, <lb/>parce qu’il ſera aiſé de les déterminer, ſur ce que je viens de dire <lb/>au ſujet de l’autrc.</s> <s xml:id="echoid-s7802" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7803" xml:space="preserve">Comme tout ce qui peut faciliter la communication des ou-<lb/>vrages apartient à ce chapitre, je crois devoir ajoûter, que quand <lb/>les foſſés d’une place ſont inondés, on fait des petits ponts à fleur <lb/>d’eau, qui vont des poternes du corps de la place à la demi-Lune, <lb/>ou à quelqu’autre ouvrage: </s> <s xml:id="echoid-s7804" xml:space="preserve">on en fait auſſi de ſemblables le long <lb/>des gorges, pour aller de la demi-Lune dans le chemin couvert, <lb/>ou dans les contregardes, ainſi qu’on le peut voir dans la 25 Plan-<lb/> <anchor type="note" xlink:label="note-0361-01a" xlink:href="note-0361-01"/> che: </s> <s xml:id="echoid-s7805" xml:space="preserve">l’on pratique pourtant quelquefois des poternes dans les fa-<lb/>ces, & </s> <s xml:id="echoid-s7806" xml:space="preserve">en ce cas le pont, qui communique aux autres ouvrages <lb/>voiſins, répond à la poterne, & </s> <s xml:id="echoid-s7807" xml:space="preserve">n’eſt plus à la gorge de la demi-<lb/>Lune; </s> <s xml:id="echoid-s7808" xml:space="preserve">c’eſt ainſi par exemple qu’au Neuf Briſack l’on communi-<lb/>que des contregardes dans les tenailles, en paſſant par les poter-<lb/>nes qui ſont aux flancs.</s> <s xml:id="echoid-s7809" xml:space="preserve"/> </p> <div xml:id="echoid-div348" type="float" level="3" n="7"> <note position="right" xlink:label="note-0361-01" xlink:href="note-0361-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>25.</note> </div> <p> <s xml:id="echoid-s7810" xml:space="preserve">Quand les foſſés ſont à ſec, on fait des Caponieres qui aſſeurent <lb/>& </s> <s xml:id="echoid-s7811" xml:space="preserve">couvrent parfaitement les communications: </s> <s xml:id="echoid-s7812" xml:space="preserve">ces caponieres ne <lb/>ſont autre choſe qu’un parapet fait en glacis à droit & </s> <s xml:id="echoid-s7813" xml:space="preserve">à gauche <lb/>du paſſage que l’on pratique dans le fond des foſſez, comme on <lb/>le peut voir ſur la Planche que je viens de citer.</s> <s xml:id="echoid-s7814" xml:space="preserve"/> </p> <pb o="56" file="0362" n="384" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div350" type="section" level="2" n="119"> <head xml:id="echoid-head268" xml:space="preserve">CHAPITRE SEPTIE’ME.</head> <head xml:id="echoid-head269" style="it" xml:space="preserve">Des Corps de Gardes en general, des Guerites & Latrines.</head> <p> <s xml:id="echoid-s7815" xml:space="preserve">INdépendamment des Corps de Gardes dont nous avons par-<lb/>lé pour veiller à la ſûreté des Portes, il s’en fait encore d’autres <lb/>dedans & </s> <s xml:id="echoid-s7816" xml:space="preserve">dehors les Places: </s> <s xml:id="echoid-s7817" xml:space="preserve">par exemple, quand les Portes ſont <lb/>trop éloignées les unes des autres pour que les Corps de Gardes qui <lb/>y ſont puiſſent poſter des Sentinelles à tous les endroits du Rem-<lb/>part où l’on juge à propos d’en poſer, l’on en conſtruit d’autres <lb/>pour être à portée de faire les rondes & </s> <s xml:id="echoid-s7818" xml:space="preserve">de veiller à ce qui ſe paſſe; <lb/></s> <s xml:id="echoid-s7819" xml:space="preserve">ſi la Ville eſt traverſée par quelque Riviere, & </s> <s xml:id="echoid-s7820" xml:space="preserve">qu’il y ait par con-<lb/>ſequent des Portes d’eau, l’on ne manque pas d’y en faire un. </s> <s xml:id="echoid-s7821" xml:space="preserve">En <lb/>un mot à tous les endroits où l’on a quelque raiſon d’y en établir, <lb/>tel eſt celui de la place d’Armes & </s> <s xml:id="echoid-s7822" xml:space="preserve">des autres répandus dans les <lb/>grandes Villes pour maintenir le bon ordre & </s> <s xml:id="echoid-s7823" xml:space="preserve">poſer des Sentinelles <lb/>aux Portes de ceux qui ont droit d’en avoir. </s> <s xml:id="echoid-s7824" xml:space="preserve">Or comme ces Corps <lb/>de Gardes ne comprennent rien de particulier dans leur conſtruc-<lb/>tion, je ne m’arrêteray point à en raporter d’autres que celui qui <lb/>eſt ſur la planche 15. </s> <s xml:id="echoid-s7825" xml:space="preserve">qui pourra ſervir de modéle en y faiſant les <lb/> <anchor type="note" xlink:label="note-0362-01a" xlink:href="note-0362-01"/> changemens que l’on croira neceſſaires, j’ajoûterai ſeulement, qu’en <lb/>conſtruiſant ceux des remparts, on fera bien d’y menager de petits <lb/>entrepots pour renfermer des munitions, afin de les avoir à portée <lb/>d’être diſtribuées aux détachemens qui ſortent de la place, pour <lb/>des eſcortes ou pour quelque expedition, & </s> <s xml:id="echoid-s7826" xml:space="preserve">n’être point dans la <lb/>peine d’ouvrir les magaſins, ſouvent pour peu de choſe: </s> <s xml:id="echoid-s7827" xml:space="preserve">ces en-<lb/>trepots ſont fort commodes en tems de ſiége, pour le ſervice du <lb/>rempart & </s> <s xml:id="echoid-s7828" xml:space="preserve">celui des dehors; </s> <s xml:id="echoid-s7829" xml:space="preserve">il eſt vrai que dans la plûpart des <lb/>grandes Villes, où l’enceinte eſt accompagnée de tours ou reduits, <lb/>on y rencontre des endroits propres pour des entrepots, mais <lb/>je ſupoſe une place neuve où l’on ſeroit privé de ces ſortes de com-<lb/>modités.</s> <s xml:id="echoid-s7830" xml:space="preserve"/> </p> <div xml:id="echoid-div350" type="float" level="3" n="1"> <note position="left" xlink:label="note-0362-01" xlink:href="note-0362-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>15.</note> </div> <p> <s xml:id="echoid-s7831" xml:space="preserve">Je crois que l’on peut auſſi comprendre, ſous le nom de corps <lb/>de garde, les redoutes de maçonnerie qui ſe font dans les dehors <lb/>des places, aux endroits où il eſt de conſequence d’avoir des poſtes <lb/>pour garder une Ecluſe, un Batardeau, un Pont, &</s> <s xml:id="echoid-s7832" xml:space="preserve">c. </s> <s xml:id="echoid-s7833" xml:space="preserve">puiſque ces <lb/>redoutes ne ſont à le bien prendre que des corps de gardes rétran-<lb/>chés: </s> <s xml:id="echoid-s7834" xml:space="preserve">quand elles ſont près de la place, on en releve la garde tous <pb file="0363" n="385"/> <pb file="0363a" n="386"/> <anchor type="figure" xlink:label="fig-0363a-01a" xlink:href="fig-0363a-01"/> <pb file="0364" n="387"/> <pb o="57" file="0365" n="388" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> les jours par de nouvelles troupes; </s> <s xml:id="echoid-s7835" xml:space="preserve">mais quand elles en ſont fort <lb/>éloignées, on y établit une petite garniſon, & </s> <s xml:id="echoid-s7836" xml:space="preserve">alors il faut qu’elles <lb/>ſoient compoſées de pluſieurs étages, pour y diſtribuer les logemens <lb/>neceſſaires aux Officiers & </s> <s xml:id="echoid-s7837" xml:space="preserve">aux Soldats: </s> <s xml:id="echoid-s7838" xml:space="preserve">& </s> <s xml:id="echoid-s7839" xml:space="preserve">ne pouvant être que fort <lb/>ſerrés dans un auſſi petit endroit, il faut faire enſorte, en les conſtrui-<lb/>ſant, de ménager ſi bien la grandeur des piéces, qu’on y puiſſe avoir <lb/>les commodités eſſentielles; </s> <s xml:id="echoid-s7840" xml:space="preserve">par exemple, ſi on peut faire un étage <lb/>ſouterrain, il faudra y pratiquer un magaſin à poudre, un autre <lb/>pour les vivres, une cave, & </s> <s xml:id="echoid-s7841" xml:space="preserve">une citerne qui recevra les eaux de <lb/>pluye, qui tomberont ſur la plate forme, ou ſur le toit, par le <lb/>moyen des goutieres: </s> <s xml:id="echoid-s7842" xml:space="preserve">enſuite au-deſſus de l’étage ſouterrain, on <lb/>en pourra faire deux ou trois autres pour loger les troupes, de la ma-<lb/>niere qu’on les voit repreſentés ſur la Planche 23, qui comprend les <lb/> <anchor type="note" xlink:label="note-0365-01a" xlink:href="note-0365-01"/> plans de deux redoutes differentes; </s> <s xml:id="echoid-s7843" xml:space="preserve">les premier ſecond & </s> <s xml:id="echoid-s7844" xml:space="preserve">quatriéme <lb/>deſſeins ſont des étages dont la troiſiéme figure repreſente le profil, <lb/>les cinquiéme ſixiéme & </s> <s xml:id="echoid-s7845" xml:space="preserve">ſeptiéme ſont ſupoſés apartenir à une autre <lb/>redoute qui ſeroit à machicoulis, c’eſt-à-dire, qui ſeroit faite de fa-<lb/>çon, que le dernier étage faiſant ſaillie en dehors ſur les deux autres <lb/>inferieurs, puiſſe voir le pied du revêtement de la redoute, pour <lb/>en deffendre l’accès: </s> <s xml:id="echoid-s7846" xml:space="preserve">je n’en ai point raporté le profil, parce qu’il <lb/>ne reſtoit pas de place ſur la Planche pour l’y tracer, mais on ju-<lb/>gera ſans peine dequoi il eſt queſtion; </s> <s xml:id="echoid-s7847" xml:space="preserve">ces redoutes ſont preſque <lb/>toûjours entourées d’un rempart, qui a ſon foſſé comme on l’a ſu-<lb/>poſé ici, pour éviter les deſſeins qu’il auroit fallu encore raporter, <lb/>ſi on avoit voulu détailler quelque choſe de plus que le corps de <lb/>la redoute.</s> <s xml:id="echoid-s7848" xml:space="preserve"/> </p> <div xml:id="echoid-div351" type="float" level="3" n="2"> <figure xlink:label="fig-0363a-01" xlink:href="fig-0363a-01a"> <image file="0363a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0363a-01"/> </figure> <note position="right" xlink:label="note-0365-01" xlink:href="note-0365-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>23.</note> </div> <p> <s xml:id="echoid-s7849" xml:space="preserve">Les Guerites, qui ſe font ſur le rempart, ſont ordinairement pla-<lb/> <anchor type="note" xlink:label="note-0365-02a" xlink:href="note-0365-02"/> cées aux angles des Baſtions, demi-Lune, & </s> <s xml:id="echoid-s7850" xml:space="preserve">autres ouvrages deta-<lb/>chés, elles doivent être de plain pied au rempart, & </s> <s xml:id="echoid-s7851" xml:space="preserve">quand elles <lb/>ſont de maçonnerie, elles peuvent être rondes, pentagonalles, ou <lb/>exagonalles, leur diamétre doit être en dedans, d’environ quatre <lb/>pieds, & </s> <s xml:id="echoid-s7852" xml:space="preserve">leur hauteur de ſix à la naiſſance de la calotte; </s> <s xml:id="echoid-s7853" xml:space="preserve">il faut <lb/>qu’elles ſoient percées de quatre ou cinq petites fenetres ouvertes, <lb/>de maniere que la ſentinelle puiſſe aiſément découvrir le fond du <lb/>foſſé, le chemin couvert, & </s> <s xml:id="echoid-s7854" xml:space="preserve">les autres dehors: </s> <s xml:id="echoid-s7855" xml:space="preserve">les trois premieres <lb/>figures de Guerites pourront ſervir de modelles, ſelon qu’on les vou-<lb/>dra plus ou moins orner; </s> <s xml:id="echoid-s7856" xml:space="preserve">les trois autres deſſeins ſont des Guerites <lb/>de charpente, pour faire aux angles des ouvrages qui ne ſont point <lb/>revêtus, l’on y voit l’aſſemblage des pieces qui les compoſent, <lb/>ſelon l’ouverture des angles droits, obtus, ou aigus: </s> <s xml:id="echoid-s7857" xml:space="preserve">quant aux <lb/>autres Guerites que l’on place indifferemment, on les fait toûjours <pb o="58" file="0366" n="389" rhead="LA SCIENCE DES INGENIEURS,"/> de figure quarrée, comme aux 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s7858" xml:space="preserve">& </s> <s xml:id="echoid-s7859" xml:space="preserve">8<emph style="sub">e</emph>. </s> <s xml:id="echoid-s7860" xml:space="preserve">deſſeins, qui s’expliquent <lb/>aſſés d’eux mêmes.</s> <s xml:id="echoid-s7861" xml:space="preserve"/> </p> <div xml:id="echoid-div352" type="float" level="3" n="3"> <note position="right" xlink:label="note-0365-02" xlink:href="note-0365-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>24.</note> </div> <p> <s xml:id="echoid-s7862" xml:space="preserve">L’on fait quelquefois des Latrines de charpente ſur le rempart, <lb/>aumilieu des courtines, quand il n’y a point de poternes au-deſſous, <lb/>parce que s’il s’y en trouvoit, il faudroit prendre garde de ne point <lb/>en falir la ſortie, ainſi ſupoſant que le corps de la place ſoit revê-<lb/> <anchor type="note" xlink:label="note-0366-01a" xlink:href="note-0366-01"/> tu, il faut commencer par poſer au niveau du terre-plain du rem-<lb/>part, des poutrelles à deux pieds & </s> <s xml:id="echoid-s7863" xml:space="preserve">demi l’une de l’autre, qui ayent <lb/>environ 20 pieds de long, ſur 10 à 12 pouces; </s> <s xml:id="echoid-s7864" xml:space="preserve">ces poutrelles doi-<lb/>vent ſaillir de 4 pieds au delà du talud du revêtement, ainſi leur <lb/>longueur étant de 20 pieds, & </s> <s xml:id="echoid-s7865" xml:space="preserve">le revétement en ayant 6 de talud, <lb/>la moitié portera ſur le rempart, & </s> <s xml:id="echoid-s7866" xml:space="preserve">l’autre moitié ſera en ſaillie, <lb/>afin de faire les Latrines de maniere, que les ordures ne tombent <lb/>point ſur la muraille: </s> <s xml:id="echoid-s7867" xml:space="preserve">pour les maintenir on y attachera avec des <lb/>liens de fer, des poteaux pendans, qui ſeront retenus entre la mu-<lb/>raille & </s> <s xml:id="echoid-s7868" xml:space="preserve">les terres du rempart; </s> <s xml:id="echoid-s7869" xml:space="preserve">& </s> <s xml:id="echoid-s7870" xml:space="preserve">pour rendre le plancher plus ſo-<lb/>lide, on peut, au-deſſous du cordon, encaſtrer dans la muraille <lb/>d’autres poteaux pendants ſous chaque poutrelle, afin de ſoûtenir <lb/>le poids des Latrines, ou bien on pourra, en conſtruiſant le revê-<lb/>tement, placer au-deſſous des endroits où on doi@ poſer les pou-<lb/>trelles des Corbeaux ou Conſoles de pierre de taille, pour apuyer les <lb/>liens, ce qui rendra l’ouvrage plus ſolide: </s> <s xml:id="echoid-s7871" xml:space="preserve">quant à l’aſſemblage du <lb/>reſte de la charpente, il n’eſt pas beſoin de l’expliquer puiſque les <lb/>plans & </s> <s xml:id="echoid-s7872" xml:space="preserve">profils qui ſont ſur la 33 Planche, en facilitent aſlés l’in-<lb/>telligence: </s> <s xml:id="echoid-s7873" xml:space="preserve">d’ailleurs, ce ſujet n’eſt pas ſi intereſſant pour mériter <lb/>une plus longue explication; </s> <s xml:id="echoid-s7874" xml:space="preserve">je l’aurois même ſuprimée, ſi, dans un <lb/>ouvrage comme celui-ci, il ne falloit parler de tout.</s> <s xml:id="echoid-s7875" xml:space="preserve"/> </p> <div xml:id="echoid-div353" type="float" level="3" n="4"> <note position="left" xlink:label="note-0366-01" xlink:href="note-0366-01a" xml:space="preserve">Voyez les <lb/>Latrines <lb/>qui ſont ſur <lb/>la Planche <lb/>33.</note> </div> <p> <s xml:id="echoid-s7876" xml:space="preserve">Quand il ſe rencontre, dans le voiſinage des Cazernes, une rivie-<lb/>re ou un ruiſſeau, il vaut beaucoup mieux en profiter pour y faire <lb/>des Latrines, que de les placer ſur le rempart, puiſque, tout bien <lb/>conſideré, elles preſentent un coup d’œil fort deſagreable; </s> <s xml:id="echoid-s7877" xml:space="preserve">mais <lb/>quand on n’a point cette commodité, je voudrois qu’on les fit ſous <lb/>le terre-plain du rempart, ou ſous les eſcaliers par leſquels on y <lb/>monte: </s> <s xml:id="echoid-s7878" xml:space="preserve">en ce cas, il faut que l’égout, où ſe raſſemblent les eaux des <lb/>ruës, reçoive les ordures pour les conduire dans le foſſé.</s> <s xml:id="echoid-s7879" xml:space="preserve"/> </p> <pb file="0367" n="390"/> <pb file="0367a" n="391"/> <figure> <image file="0367a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0367a-01"/> </figure> <pb file="0368" n="392"/> <pb o="59" file="0369" n="393" rhead="LIVRE IV. DES EDIFICES MILITAIRES"/> </div> <div xml:id="echoid-div355" type="section" level="2" n="120"> <head xml:id="echoid-head270" xml:space="preserve">CHAPITRE HUITIE’ME.</head> <head xml:id="echoid-head271" style="it" xml:space="preserve">De la Diſtribution des Ruës dans les Villes de Guerre.</head> <p> <s xml:id="echoid-s7880" xml:space="preserve">QUand l’eſpace, que l’on veut fortifier, n’eſt point occupé par <lb/>quelque ancienne habitation, on ne doit rien negliger pour <lb/>faire regner dans l’interieur de la place le plus de regularité <lb/>qu’il eſt poſſible, ſoit pour la diſtribution des ruës, celle des mai-<lb/>ſons de Bourgeois, l’emplacement des Corps de Garde, Cazernes, <lb/>magaſins à poudre, arſenaux, cantines, boulangeries, & </s> <s xml:id="echoid-s7881" xml:space="preserve">logemens <lb/>d’état Major, afin que tous ces édifices répondent au reſte de la <lb/>place, de façon que chacun puiſſe être à portée de remplir ſon ob-<lb/>jet principal; </s> <s xml:id="echoid-s7882" xml:space="preserve">&</s> <s xml:id="echoid-s7883" xml:space="preserve">, pour mieux juger de cette diſpoſition, je donne-<lb/> <anchor type="note" xlink:label="note-0369-01a" xlink:href="note-0369-01"/> rai pour modelle le plan des ruës du Neuf-Briſack, comme le plus <lb/>parfait que je connoiſſe.</s> <s xml:id="echoid-s7884" xml:space="preserve"/> </p> <div xml:id="echoid-div355" type="float" level="3" n="1"> <note position="right" xlink:label="note-0369-01" xlink:href="note-0369-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>25.</note> </div> <p> <s xml:id="echoid-s7885" xml:space="preserve">Quand on peut diſpoſer d’un grand terrain, il eſt à propos, pour <lb/>la commodité du public, de faire pluſieurs places; </s> <s xml:id="echoid-s7886" xml:space="preserve">mais ſi on en <lb/>étoit empêché par une raiſon contraire, il faudroit au moins en fai-<lb/>re une au centre, & </s> <s xml:id="echoid-s7887" xml:space="preserve">lui donner une figure quarrée; </s> <s xml:id="echoid-s7888" xml:space="preserve">ſa grandeur <lb/>doit être proportionnée à celle de l’enceinte, par conſequent la <lb/>quantité de troupes qui veilleront à ſa conſervation; </s> <s xml:id="echoid-s7889" xml:space="preserve">car cette pla-<lb/>ce devant ſervir à aſſembler la garniſon, pour le ſervice journa-<lb/>lier, il faut qu’elle ait une capacité raiſonnable. </s> <s xml:id="echoid-s7890" xml:space="preserve">J’eſtime donc qu’à <lb/>une Fortification de ſix Baſtions, ſur la baſe de 180 toiſes, on pour-<lb/>ra donner à la place d’armes 40 à 45 toiſes en quarré, à celle de 7 <lb/>Baſtions, 55 à 60, pour une à 8, 70 à 75, pour celle qui en auroit <lb/>9 ou 10, 80 à 85, enfin à celle qui en auroit 11 ou 12, 90 à 95: <lb/></s> <s xml:id="echoid-s7891" xml:space="preserve">au reſte, il vaut mieux s’en raporter à<unsure/> la diſcrétion des Ingenieurs, <lb/>qui executent de pareils deſſeins, qu’à aucune regle particuliere.</s> <s xml:id="echoid-s7892" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7893" xml:space="preserve">On fait ordinairement une petite place d’armes devant chaque <lb/>porte de la Ville, afin que les corps de garde qui y ſont ayent <lb/>devant eux une eſpece d’eſplanade, pour ſe garentir des ſurpriſes <lb/>du dedans: </s> <s xml:id="echoid-s7894" xml:space="preserve">d’ailleurs, ces petites places font un bel effet, & </s> <s xml:id="echoid-s7895" xml:space="preserve">ſont fort <lb/>commodes pour degager le paſſage, quand les voitures qui veulent <lb/>ſortir de la Ville ſont obligées d’attendre que celles qui ſont ſur <lb/>les ponts ſoient entrées.</s> <s xml:id="echoid-s7896" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7897" xml:space="preserve">Quant aux ruës, il faut que les principales partent de la place <lb/>d’armes, pour aller ſur un même allignement aux portes de la Ville, <pb o="60" file="0370" n="394" rhead="LA SCIENCE DES INGENIEURS,"/> aux remparts, & </s> <s xml:id="echoid-s7898" xml:space="preserve">principalement à la Citadelle, ou au reduit s’il y <lb/>en a, afin qu’elles puiſſent être enfilées; </s> <s xml:id="echoid-s7899" xml:space="preserve">on obſervera qu’elles ſoient <lb/>perpendiculaires les unes aux autres autant qu’il eſt poſſible, pour <lb/>que les encoignures des maiſons ſoient à angle droit: </s> <s xml:id="echoid-s7900" xml:space="preserve">on leur don-<lb/>ne ordinairement ſix toiſes de large, afin que trois chariots puiſ-<lb/>ſent paſſer de front, & </s> <s xml:id="echoid-s7901" xml:space="preserve">que s’il s’en rencontroit un d’arrêté de cha-<lb/>que côté de la ruë, un troiſiéme pût paſſer entre - deux, de ſor-<lb/>te qu’il reſte aſſez d’eſpace pour les gens de pied & </s> <s xml:id="echoid-s7902" xml:space="preserve">de cheval; <lb/></s> <s xml:id="echoid-s7903" xml:space="preserve">pour les petites ruës, on ſe contente de leur donner 3 à 4 toi-<lb/>ſes de largeur.</s> <s xml:id="echoid-s7904" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7905" xml:space="preserve">La diſtance d’une ruë, à celle qui lui eſt paralelle, doit être telle, <lb/>qu’entre l’une & </s> <s xml:id="echoid-s7906" xml:space="preserve">l’autre, il y reſte un eſpace pour deux maiſons <lb/>de Bourgeois, dont l’une regarde dans une ruë, & </s> <s xml:id="echoid-s7907" xml:space="preserve">l’autre dans cel-<lb/>le opoſée; </s> <s xml:id="echoid-s7908" xml:space="preserve">chacune de ces maiſons doit avoir environ 5 à 6 toiſes <lb/>de face, ſur 7 à 8 d’enfoncement, avec une cour de pareille gran-<lb/>deur, pour que l’intervale d’une ruë à l’autre ſoit d’environ 32 ou <lb/>33 toiſes; </s> <s xml:id="echoid-s7909" xml:space="preserve">dans cette largeur on peut aiſément trouver l’étenduë <lb/>qu’il faut pour les grandes maiſons, qui auroient écuries & </s> <s xml:id="echoid-s7910" xml:space="preserve">jardins.</s> <s xml:id="echoid-s7911" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7912" xml:space="preserve">Dans les Villes où il y a des ruës anciennes, on les laiſſe telles <lb/>qu’elles ſont, on ſe contente ſeulement de redreſſer ou d’élargir <lb/>les plus eſſentielles, comme celles des entrées & </s> <s xml:id="echoid-s7913" xml:space="preserve">ſorties: </s> <s xml:id="echoid-s7914" xml:space="preserve">on en <lb/>fait de même à l’égard de la place d’armes, quand il ne s’en trou-<lb/>ve point d’aſſés grande pour faire le ſervice ordinaire.</s> <s xml:id="echoid-s7915" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7916" xml:space="preserve">Independamment du corps de garde de la place d’armes, & </s> <s xml:id="echoid-s7917" xml:space="preserve">de <lb/>ceux des portes, on en fait encore ſur le rempart, pour avoir des <lb/>poſtes qui ſoient à portée de veiller à la ſureté du corps de la place: <lb/></s> <s xml:id="echoid-s7918" xml:space="preserve">ils ſe font quelquefois au centre ou aux gorges des Baſtions, quand <lb/>il n’y a point de cavaliers ou de magaſins à poudre, ou bien on <lb/>les place dans le milieu des courtines, principalement quand il y <lb/>a quelque porte d’eau, occaſionnée par les rivieres.</s> <s xml:id="echoid-s7919" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7920" xml:space="preserve">Les Magaſins à poudre devant être éloignés, le plus qu’il eſt poſ-<lb/>ſible, des maiſons des habitans, on ne peut guere mieux les pla-<lb/>cer, que dans le milieu des Baſtions.</s> <s xml:id="echoid-s7921" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7922" xml:space="preserve">Comme l’Arſenal eſt un des Edifices militaires qui doit occuper <lb/>le plus d’eſpace, il eſt aſſés difficile d’en déterminer l’emplacement, <lb/>parce que cela depend de mille circonſtances qu’on ne peut apper-<lb/>cevoir que ſur les lieux; </s> <s xml:id="echoid-s7923" xml:space="preserve">mais on aura au moins attention de le dé-<lb/>tacher de tout autre Bâtiment, tant pour la ſûreté des munitions, que <lb/>pour ne point participer aux incendies qui pourroient arriver dans <lb/>ſon voiſinage. </s> <s xml:id="echoid-s7924" xml:space="preserve">Quand il paſſe une riviere dans la Ville, il eſt eſſen-<lb/>tiel, pour le bien du ſervice, que l’Arſenal n’en ſoit point éloigné, <pb file="0371" n="395"/> <pb file="0371a" n="396"/> <anchor type="figure" xlink:label="fig-0371a-01a" xlink:href="fig-0371a-01"/> <pb file="0372" n="397"/> <pb o="61" file="0373" n="398" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> afin d’être plus à portée de former les convois qui pourront ſe faire <lb/>par la navigation. </s> <s xml:id="echoid-s7925" xml:space="preserve">Nous reprendrons cet article dans le Chapitre <lb/>neuviéme.</s> <s xml:id="echoid-s7926" xml:space="preserve"/> </p> <div xml:id="echoid-div356" type="float" level="3" n="2"> <figure xlink:label="fig-0371a-01" xlink:href="fig-0371a-01a"> <image file="0371a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0371a-01"/> </figure> </div> <p> <s xml:id="echoid-s7927" xml:space="preserve">Les Cazernes ſe placent ordinairement proche le Rempart, le <lb/>long des Courtines, & </s> <s xml:id="echoid-s7928" xml:space="preserve">c’eſt en effet la ſituation qui leur convient <lb/>le mieux, parce qu’on y peut ménager un eſpace pour faire faire <lb/>l’exercise, le Soldat eſt plus détaché de la Bourgeoiſie, on peut <lb/>faire plus ſecretement les détachemens qui doivent marcher pour <lb/>quelque entrepriſe, au lieu que par-tout ailleurs les mêmes avan-<lb/>tages ne ſe rencontreroient peut-être pas ſans difficulté.</s> <s xml:id="echoid-s7929" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7930" xml:space="preserve">Comme la Cantine & </s> <s xml:id="echoid-s7931" xml:space="preserve">la Boulangerie regardent la ſubſiſtance de <lb/>la Garniſon, on doit les placer dans le voiſinage des Cazernes & </s> <s xml:id="echoid-s7932" xml:space="preserve"><lb/>même dans l’endroit où il ſe rencontre près de-là un Corps de Garde <lb/>qui ſoit en état d’en impoſer en cas de deſordre.</s> <s xml:id="echoid-s7933" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7934" xml:space="preserve">Pour l’Hôpital, il eſt preſque inutile de dire qu’il eſt à propos de <lb/>le placer dans un endroit écarté; </s> <s xml:id="echoid-s7935" xml:space="preserve">mais, ſur toute choſe, proche une <lb/>rivierre ou ruiſſeau, s’il en paſſe dans la Ville.</s> <s xml:id="echoid-s7936" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7937" xml:space="preserve">A l’égard des logemens de l’état Major, il eſt naturel qu’ils ré-<lb/>pondent à la Place d’Armes, ceux des Capitaines des Portes ſe font <lb/>ordinairement au-deſſus des Portes mêmes, ces logemens peuvent <lb/>auſſi ſervir pour les Aydes-Majors de la Place.</s> <s xml:id="echoid-s7938" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7939" xml:space="preserve">Pour dire auſſi un mot de l’emplacement de l’Egliſe, il convient <lb/>que quand il n’y a qu’une Paroiſſe, comme cela eſt aſſés ordinaire <lb/>dans les Villes neuves, qu’elle ſoit ſituée ſur la Place, afin qu’étant <lb/>au centre de la Ville, les Habitans en ſoient également à portée.</s> <s xml:id="echoid-s7940" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7941" xml:space="preserve">A l’égard de la décoration, on ne doit rien négliger de ce qui peut <lb/>flater le coup d’œil, afin qu’il regne par-tout un air de ſimetrie qui <lb/>répande autant de grace dans l’interieur, que la force & </s> <s xml:id="echoid-s7942" xml:space="preserve">la ſolidité <lb/>des Fortifictions donnera de Majeſté à l’extrerieur.</s> <s xml:id="echoid-s7943" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7944" xml:space="preserve">Voilà en gros ce que je m’étois propoſé d’inſinuer dans ce Cha-<lb/>pitre: </s> <s xml:id="echoid-s7945" xml:space="preserve">tout ce qui en fait l’objet eſt de ſi petite conſéquence, que je <lb/>ne crois pas devoir l’étendre davantage, puiſqu’il ne faut que le <lb/>ſens-commun pour voir la neceſſité de ſemblables diſtributions; <lb/></s> <s xml:id="echoid-s7946" xml:space="preserve">mais, ce qui demande plus de capacité & </s> <s xml:id="echoid-s7947" xml:space="preserve">d’intelligence, c’eſt l’exe-<lb/>cution, tant des Edifices dont je viens de parler, que de ceux dont <lb/>on va voir les détails dans les Chapitres ſuivans.</s> <s xml:id="echoid-s7948" xml:space="preserve"/> </p> <pb o="62" file="0374" n="399" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div358" type="section" level="2" n="121"> <head xml:id="echoid-head272" xml:space="preserve">CHAPITRE NEUVIEME.</head> <head xml:id="echoid-head273" style="it" xml:space="preserve">Des Magaſins à Poudre & Arſenaux pour les Munitions <lb/>de Guerre.</head> <p> <s xml:id="echoid-s7949" xml:space="preserve">ON ne faiſoit pas autrefois de Magaſins comme on l’a prati-<lb/>qué dans ces derniers tems, on reſſerroit la Poudre dans <lb/>des Tours attachées au corps de la Place, ce qui étoit ſujet à de <lb/>grands accidens, car quand le feu venoit à y prendre, ſoit par haſard, <lb/>ou par le deſſein concertée de quelque trahiſon, il ſe formoit une <lb/>brêche dont l’ennemi pouvoit ſe prévaloir, comme cela eſt arrivé <lb/>à Aire du tems que cette Place apartenoit à l’Eſpagne: </s> <s xml:id="echoid-s7950" xml:space="preserve">les François <lb/>qui en faiſoient le Siége, d’intelligence avec un habitant, trouve-<lb/>rent moyen de mettre le feu aux Poudres qui étoient dans le ſoû-<lb/>rerrain d’un Baſtion, elles firent un ſi grand effet, qu’une partie <lb/>du Rempart fut renverſée dans le Foſſé, & </s> <s xml:id="echoid-s7951" xml:space="preserve">un Cavalier qui occu-<lb/>poit le terre-plain partagé en deux monticules que l’on voit en-<lb/>core; </s> <s xml:id="echoid-s7952" xml:space="preserve">les Aſſiégeans s’étant preſentés ſur la contreſcarpe pour mon-<lb/>ter à l’Aſſaut, la Garniſon fut obligée de ſe rendre plûtôt qu’elle ne <lb/>l’eût fait.</s> <s xml:id="echoid-s7953" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7954" xml:space="preserve">Quand on vit de quelle conſéquence il étoit de ſéparer les Ma-<lb/>gaſins de l’enceinte, on en batit de differente figure; </s> <s xml:id="echoid-s7955" xml:space="preserve">mais on fut <lb/>longtems avant de rencontrer les juſtes proportions qu’il falloit leur <lb/>donner: </s> <s xml:id="echoid-s7956" xml:space="preserve">les plus ordinaires ſe faiſoient comme celui qui eſt re-<lb/>preſenté par le premier & </s> <s xml:id="echoid-s7957" xml:space="preserve">le deuxiéme deſſein de la Planche 26. <lb/></s> <s xml:id="echoid-s7958" xml:space="preserve"> <anchor type="note" xlink:label="note-0374-01a" xlink:href="note-0374-01"/> où l’on voit qu’on les couvroit par pluſieurs Voûtes d’arrête apuyées <lb/>dans le milieu ſur deux ou trois pilliers; </s> <s xml:id="echoid-s7959" xml:space="preserve">mais comme pour réünir <lb/>ces Voûtes ſous les mêmes pentes du toit, il falloit faire un maſſif <lb/>conſidérable de Maçonnerie qui les chargeoit extraordinairement, <lb/>on convint qu’il valloit beaucoup mieux les couvrir d’une ſeule <lb/>Voûte que l’on fit d’abord en tiers-point, comme on le peut voir <lb/>dans le cinquiéme & </s> <s xml:id="echoid-s7960" xml:space="preserve">ſixiéme deſſein de la même Planche: </s> <s xml:id="echoid-s7961" xml:space="preserve">l’on pra-<lb/>tiquoit à la naiſſance de la Voûte un plancher pour faire une eſpece <lb/>de Grenier, afin d’y reſſerrer les Poudres qui ne pouvoient pas être <lb/>contenues au rez-de-Chauſſée.</s> <s xml:id="echoid-s7962" xml:space="preserve"/> </p> <div xml:id="echoid-div358" type="float" level="3" n="1"> <note position="left" xlink:label="note-0374-01" xlink:href="note-0374-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>26. <lb/><emph style="sc">Fig</emph>. 1. <lb/>& 2.</note> </div> <p> <s xml:id="echoid-s7963" xml:space="preserve">Mr. </s> <s xml:id="echoid-s7964" xml:space="preserve">de Vauban ayant remarqué dans pluſieurs Siéges, que les <lb/>Voûtes en tiers-point étoient trop foibles, & </s> <s xml:id="echoid-s7965" xml:space="preserve">que le Grenier ne fai-<lb/>ſoit que charger les piés-droits fort mal-à-propos, puiſque la pru- <pb o="63" file="0375" n="400" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> dence ne vouloit pas qu’on avanturât tant de Poudre dans un même <lb/>Magaſin, étant plus convenable de la partager dans differens en-<lb/>droits, rejetta abſolument toutes les conſtructions qui avoient été <lb/>en uſage juſqu’alors, & </s> <s xml:id="echoid-s7966" xml:space="preserve">en propoſa une nouvelle beaucoup plus <lb/>parfaite, qui eſt celle qu’on voit répreſentée par le premier & </s> <s xml:id="echoid-s7967" xml:space="preserve">le ſe-<lb/>cond deſſein de la 27 Planche, qui a toûjours été executée avec <lb/> <anchor type="note" xlink:label="note-0375-01a" xlink:href="note-0375-01"/> ſuccès, quoiqu’on pourroit la rendre encore plus parfaite en y chan-<lb/>geant quelque choſe, comme je le ferai voir dans la ſuite.</s> <s xml:id="echoid-s7968" xml:space="preserve"/> </p> <div xml:id="echoid-div359" type="float" level="3" n="2"> <note position="right" xlink:label="note-0375-01" xlink:href="note-0375-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>27. <lb/><emph style="sc">Fig</emph>. 1. <lb/>& 2.</note> </div> <p> <s xml:id="echoid-s7969" xml:space="preserve">Je n’ai jamais conſideré ſerieuſement ce deſſein, ſans avoir été <lb/>ravi d’admiration, en remarquant que ce grand Homme avoit ren-<lb/>contré à peu de choſe près, par la juſteſſe de ſon eſprit & </s> <s xml:id="echoid-s7970" xml:space="preserve">ſa grande <lb/>experience, des proportions preſque auſſi exactes que celles qu’au-<lb/>roit pû donner une parfaite connoiſſance de la Mécanique des <lb/>Voûtes. </s> <s xml:id="echoid-s7971" xml:space="preserve">Voilà l’avantage des Génies ſuperieurs; </s> <s xml:id="echoid-s7972" xml:space="preserve">s’ils ne frapent pas <lb/>directement au but, du moins ils ne s’en écartent guére. </s> <s xml:id="echoid-s7973" xml:space="preserve">Tous <lb/>les Magaſins qui ont été conſtruits dans ce goût-là ſe ſont ſoûte-<lb/>nus juſqu’à preſent, ſans qu’il leur ſoit arrivé aucun accident, même <lb/>dans les Places aſſiégées qui ont le plus ſouffert des Bombes; </s> <s xml:id="echoid-s7974" xml:space="preserve">il en <lb/>eſt tombé à Landaw plus de 80 ſur un ſemblable Magaſin, ſans que <lb/>la Voûte en ait été aucunement endommagée, la même choſe eſt <lb/>arrivée à Ath & </s> <s xml:id="echoid-s7975" xml:space="preserve">à pluſieurs autres endroits. </s> <s xml:id="echoid-s7976" xml:space="preserve">Mr. </s> <s xml:id="echoid-s7977" xml:space="preserve">Demus Directeur <lb/>des Fortifications, auquel on peut bien s’en raporter, m’a dit <lb/>qu’au dernier Siége de Tournay, où il étoit, les ennemis jette-<lb/>rent plus de 45000 Bombes dans la Citadelle, dont le plus grand <lb/>nombre tomba ſur deux Magaſins qui n’en furent point ébranlés, <lb/>parce que les Voûtes étoient en plain ceintre, de même que celui <lb/>de Landaw, au lieu que deux Soûterrains voûtés en tiers-point <lb/>furent enfoncés à la troiſiéme ou quatriéme Bombe, quoique cou-<lb/>verts de 5 à 6 pieds de terre, depuis plus de 40. </s> <s xml:id="echoid-s7978" xml:space="preserve">ans.</s> <s xml:id="echoid-s7979" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7980" xml:space="preserve">Si l’on joint à de pareilles experiences tout ce que la raiſon peut <lb/>inſpirer, on n’héſitera point de donner la préference à la Voûte en <lb/>plain ceintre, ſur celle en tiers-point, & </s> <s xml:id="echoid-s7981" xml:space="preserve">de ſe conformer au deſſein <lb/>de Mr. </s> <s xml:id="echoid-s7982" xml:space="preserve">de Vauban: </s> <s xml:id="echoid-s7983" xml:space="preserve">ceux qui ont été d’un ſentiment opoſé ne s’en <lb/>ſont pas mieux trouvés; </s> <s xml:id="echoid-s7984" xml:space="preserve">mais il eſt neceſſaire qu’il arrive des acci-<lb/>dens qui faſſent ſentir la conſéquence de ne point s’écarter des <lb/>bonnes maximes pour ne ſuivre que le haſard ou le caprice: </s> <s xml:id="echoid-s7985" xml:space="preserve">le <lb/>droit de réformer ne s’acquiert point impunément, & </s> <s xml:id="echoid-s7986" xml:space="preserve">il n’y a qu’u-<lb/>ne longue pratique accompagnée d’une certaine théorie, qui puiſſe <lb/> <anchor type="note" xlink:label="note-0375-02a" xlink:href="note-0375-02"/> en donner la poſſeſſion.</s> <s xml:id="echoid-s7987" xml:space="preserve"/> </p> <div xml:id="echoid-div360" type="float" level="3" n="3"> <note position="right" xlink:label="note-0375-02" xlink:href="note-0375-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>26. <lb/><emph style="sc">Fig</emph>. 1. <lb/>& 2.</note> </div> <p> <s xml:id="echoid-s7988" xml:space="preserve">Les Magaſins ſuivant le modele de Mr. </s> <s xml:id="echoid-s7989" xml:space="preserve">le Marêchal de Vauban <lb/>ſe font ordinairement de 10 toiſes de longueur dans œuvre ſur 25 <lb/>pieds de largeur.</s> <s xml:id="echoid-s7990" xml:space="preserve"/> </p> <pb o="64" file="0376" n="401" rhead="LASCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s7991" xml:space="preserve">Pour les fondemens des longs côtés on leur donne 9 ou ro pieds <lb/>d’épaiſſeur, & </s> <s xml:id="echoid-s7992" xml:space="preserve">la profondeur ſe détermine ſelon la nature du fond <lb/>ſur lequel l’on veut bâtir: </s> <s xml:id="echoid-s7993" xml:space="preserve">car je ne ſaurois croire que cette pro-<lb/>fondeur ait été reglée à 15 pieds, comme je l’ai vû ſur un deſſein <lb/>ſigné de Mr. </s> <s xml:id="echoid-s7994" xml:space="preserve">de Vauban, puiſqu’il ſemble que 6 pieds ſont plus que <lb/>ſuffiſans; </s> <s xml:id="echoid-s7995" xml:space="preserve">mais il ſe peut que ce deſſein ait été projetté pour être <lb/>executé dans un endroit qui exigeoit qu’on en uſât ainſi.</s> <s xml:id="echoid-s7996" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s7997" xml:space="preserve">Sur ces fondemens on éleve les piés-droits de 9 pieds d’épaiſſeur <lb/>lorſque la Maçonnerie n’eſt pas des meilleures, & </s> <s xml:id="echoid-s7998" xml:space="preserve">de 8 pieds ſeu-<lb/>lement lorqu’elle ſe trouve compoſée de bons matériaux: </s> <s xml:id="echoid-s7999" xml:space="preserve">& </s> <s xml:id="echoid-s8000" xml:space="preserve">ne <lb/>faiſant point de Grenier, il ſuffit de leur donner 8 pieds de hauteur <lb/>au-deſſus de la retraite; </s> <s xml:id="echoid-s8001" xml:space="preserve">de ſorte que quand le plancher du Magaſin <lb/>eſt élévé au-deſſus du rez-de-Chauſſée, autant qu’il eſt neceſſaire <lb/>pour le mettre à l’abry de l’humidité, il reſte à peu-près 6 pieds de-<lb/>puis l’aire du plancher juſqu’à la naiſſance de la Voûte.</s> <s xml:id="echoid-s8002" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8003" xml:space="preserve">La Voûte ſe fait de 3 pieds d’épaiſſeur au milieu des reins & </s> <s xml:id="echoid-s8004" xml:space="preserve">com-<lb/>poſée de quatre Voûtes de briques repetées l’une ſur l’autre, l’ex-<lb/>trados de la derniere terminée en pente, dont la direction ſe déter-<lb/>mine en donnant 8 pieds d’épaiſſeur au-deſſus de la clef, ce qui <lb/>rend l’angle du faîte un peu plus ouvert qu’un droit.</s> <s xml:id="echoid-s8005" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8006" xml:space="preserve">Les deux pignons ſe font chacun de 4 pieds d’épaiſſeur élevé juſ-<lb/>qu’aux pentes du toit & </s> <s xml:id="echoid-s8007" xml:space="preserve">même un peu au-deſſus, comme cela ſe <lb/>pratique à tous les Edifices. </s> <s xml:id="echoid-s8008" xml:space="preserve">A l’égard des fondemens de ces pignons <lb/>on leur donne 5 pieds d’épaiſſeur, & </s> <s xml:id="echoid-s8009" xml:space="preserve">autant de profondeur que ceux <lb/>des longs côtés.</s> <s xml:id="echoid-s8010" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8011" xml:space="preserve">Les piés-droits ou longs côtés ſe ſoûtiennent par quatre contre-<lb/>forts de 6 pieds d’épaiſſeur & </s> <s xml:id="echoid-s8012" xml:space="preserve">de 4 de longueur, eſpacés de 12 <lb/>pieds les uns des autres.</s> <s xml:id="echoid-s8013" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8014" xml:space="preserve">Dans le milieu de l’intervalle d’un contrefort à l’autre, on prati-<lb/>que des évents pour donner de l’air aux Magaſins, les dez de ces <lb/>évents ont ordinairement un pied & </s> <s xml:id="echoid-s8015" xml:space="preserve">demi en tout ſens, & </s> <s xml:id="echoid-s8016" xml:space="preserve">l’eſpace <lb/>vuide pratiqué autour ſe fait de 3 pouces de largeur contourné <lb/>de maniere qu’ils aboutiſſent au parement exterieur & </s> <s xml:id="echoid-s8017" xml:space="preserve">interieur en <lb/>forme de creneaux. </s> <s xml:id="echoid-s8018" xml:space="preserve">Ces dez ſervent à empêcher que des gens mal-<lb/>intentionnés ne puiſſent jetter quelque feu d’artifice pour faire ſau-<lb/>ter le Magaſin; </s> <s xml:id="echoid-s8019" xml:space="preserve">& </s> <s xml:id="echoid-s8020" xml:space="preserve">pour prévenir un ſemblable malheur, il eſt à <lb/>propos de fermer encore les fentes des évents par pluſieurs pla-<lb/>ques de fer percées, parce qu’autrement on pourroit attacher à la <lb/>queuë d’un animal la machine qu’on voudroit y introduire, ce qui <lb/>ne ſeroit pas difficile, puiſqu’on a trouvé pluſieurs fois, dans des Ma-<lb/>gaſins, des coquilles d’œufs, & </s> <s xml:id="echoid-s8021" xml:space="preserve">des volailles, que les Fouïnes y avoient <lb/>portées.</s> <s xml:id="echoid-s8022" xml:space="preserve"/> </p> <pb file="0377" n="402"/> <pb file="0377a" n="403"/> <figure> <image file="0377a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0377a-01"/> </figure> <pb file="0378" n="404"/> <pb o="65" file="0379" n="405" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s8023" xml:space="preserve">Après que l’aire du Magaſin eſt bien arraſée, on y fait un couchis <lb/>de lambourdes de bois de chêne de 8 à 9 pouces de goſſeur, eſpa-<lb/>cés à un pied & </s> <s xml:id="echoid-s8024" xml:space="preserve">demi les unes des autres, dont l’intervalle ſe remplit <lb/>de charbon ou de recoupes de pierres, puis on recouvre le tout <lb/>de deux planchers de madriers de 2 pouces d’épaiſſeur chacun po-<lb/>ſés l’un ſur l’autre.</s> <s xml:id="echoid-s8025" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8026" xml:space="preserve">Pour éclairer le Magaſin, on fait une fenêtre dans chaque pignon <lb/>que l’on ferme avec deux venteaux de madriers de deux ou trois <lb/>pouces d’épaiſſeur, dont l’un eſt en dehors & </s> <s xml:id="echoid-s8027" xml:space="preserve">l’autre en dedans. </s> <s xml:id="echoid-s8028" xml:space="preserve">Celui <lb/>de dehors eſt couvert de taule, & </s> <s xml:id="echoid-s8029" xml:space="preserve">ſe ferme auſſi-bien que l’autre <lb/>avec deux bons verroux: </s> <s xml:id="echoid-s8030" xml:space="preserve">ces fenêtres ſe font fort élevées, crainte <lb/>des accidens; </s> <s xml:id="echoid-s8031" xml:space="preserve">on les ouvre avec le ſecours d’une échelle, pour <lb/>donner de l’air au Magaſin pendant les beaux jours.</s> <s xml:id="echoid-s8032" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8033" xml:space="preserve">On ferme auſſi les Magaſins par deux portes de bons madriers <lb/>qui s’ouvrent en dehors & </s> <s xml:id="echoid-s8034" xml:space="preserve">en dedans: </s> <s xml:id="echoid-s8035" xml:space="preserve">celle de dehors eſt recou-<lb/>verte de taule, & </s> <s xml:id="echoid-s8036" xml:space="preserve">n’a qu’une ſerrure: </s> <s xml:id="echoid-s8037" xml:space="preserve">celle de dedans en a deux qui <lb/>ont chacune leur clef differente; </s> <s xml:id="echoid-s8038" xml:space="preserve">le Gouverneur ou le Comman-<lb/>dant de la Place en a une, le Lieutenant d’Artillerie l’autre; </s> <s xml:id="echoid-s8039" xml:space="preserve">& </s> <s xml:id="echoid-s8040" xml:space="preserve">le <lb/>Garde-Magaſin celle de la premiere porte: </s> <s xml:id="echoid-s8041" xml:space="preserve">il eſt à propos, autant <lb/>qu’on le peut, que l’entrée regarde le midi, ou au moins le levant, <lb/>afin que le Magaſin ſoit orienté avantageuſement, pour être éclai-<lb/>ré du ſoleil quand on veut lui donner de l’air.</s> <s xml:id="echoid-s8042" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8043" xml:space="preserve">Pour empêcher qu’on n’aproche des Magaſins, on fait à 12 pieds <lb/>de diſtance un mur de cloture, d’un pied & </s> <s xml:id="echoid-s8044" xml:space="preserve">demi d’épaiſſeur & </s> <s xml:id="echoid-s8045" xml:space="preserve">de <lb/>9 ou 10 de hauteur.</s> <s xml:id="echoid-s8046" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8047" xml:space="preserve">Un Magaſin, tel que celui-ci, peut contenir 94800 liv. </s> <s xml:id="echoid-s8048" xml:space="preserve">de pou-<lb/>dre, engerbés de 3 barils ſeulement, car lors qu’il y en a 4 ou 5, <lb/>les premiers ſe trouvant trop chargés, les cercles & </s> <s xml:id="echoid-s8049" xml:space="preserve">les douves ſe <lb/>desuniſſent, & </s> <s xml:id="echoid-s8050" xml:space="preserve">la poudre tamiſe, ce qui peut être ſujet à de grands <lb/>accidens.</s> <s xml:id="echoid-s8051" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8052" xml:space="preserve">Les Dimenſions precedentes paroiſſent ſi bien reglées, que je <lb/>ne crois pas qu’on puiſſe en ſuivre de meilleures: </s> <s xml:id="echoid-s8053" xml:space="preserve">car l’on eſt ſûr, <lb/>que la Voûte eſt abſolument à l’épreuve de la bombe, & </s> <s xml:id="echoid-s8054" xml:space="preserve">que l’é-<lb/>paiſſeur des longs côtés eſt parfaitement bien déterminée, en la <lb/>faiſant de 8 pieds; </s> <s xml:id="echoid-s8055" xml:space="preserve">car ayant cherché de combien elle devoit être, <lb/>pour ſoutenir en équilibre la pouſſée de la Voûte, j’ai trouvé 7 <lb/>pieds & </s> <s xml:id="echoid-s8056" xml:space="preserve">environ 8 pouces: </s> <s xml:id="echoid-s8057" xml:space="preserve">voilà une occaſion où la pratique ſem-<lb/>ble avoir prevenu la theorie, & </s> <s xml:id="echoid-s8058" xml:space="preserve">l’on voit bien que Mr. </s> <s xml:id="echoid-s8059" xml:space="preserve">de Vau-<lb/>ban n’a pas eu recours à la regle des Architectes, dont j’ai fait <lb/>mention au commencement du ſecond Livre; </s> <s xml:id="echoid-s8060" xml:space="preserve">& </s> <s xml:id="echoid-s8061" xml:space="preserve">ce qui me ravit <lb/>d’admiration encore une fois, c’eſt que dans preſque tous les cas <pb o="66" file="0380" n="406" rhead="LA SCIENCE DES INGENIEURS,"/> eſſentiels, où j’ai fait un paralelle de ſes maximes, avec les loix de <lb/>la mécanique, j’ai remarqué que l’un & </s> <s xml:id="echoid-s8062" xml:space="preserve">l’autre étoient preſque toû-<lb/>jours d’accord. </s> <s xml:id="echoid-s8063" xml:space="preserve">Un ſuccès ſi heureux doit être attribué, (comme <lb/>je l’ai ouï dire à Mr. </s> <s xml:id="echoid-s8064" xml:space="preserve">le Comte de Vauban ſon neveu) aux con-<lb/>noiſſances qu’il tiroit de l’examen des anciens Edifices, & </s> <s xml:id="echoid-s8065" xml:space="preserve">au plai-<lb/>ſir qu’il prenoit de ſe communiquer ſouvent avec les plus habiles <lb/>Geometres, & </s> <s xml:id="echoid-s8066" xml:space="preserve">même avec les ouvriers, dès qu’il leur apercevoit <lb/>quelque merite: </s> <s xml:id="echoid-s8067" xml:space="preserve">il propoſoit des problêmes aux uns, & </s> <s xml:id="echoid-s8068" xml:space="preserve">des diffi-<lb/>cultés aux autres, ſouvent après les avoir reſolus lui-même; </s> <s xml:id="echoid-s8069" xml:space="preserve">ſa <lb/>grande capacité lui faiſoit developer les reſſorts de la theorie la <lb/>plus abſtraite, il ſuffiſoit qu’on s’énonçât clairement, & </s> <s xml:id="echoid-s8070" xml:space="preserve">qu’on le <lb/>conduiſit ſur les voyes, pour arriver ſouvent le premier au dernier <lb/>terme de la ſolution.</s> <s xml:id="echoid-s8071" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8072" xml:space="preserve">Les choſes qui paroiſſent les plus parfaites, n’étant point exemp-<lb/>tes de quelques petites corrections, je voudrois pour plus de ſo-<lb/>lidité changer la diſpoſition des contreforts du Magaſin de Mr. </s> <s xml:id="echoid-s8073" xml:space="preserve">de <lb/>Vauban: </s> <s xml:id="echoid-s8074" xml:space="preserve">par exemple, au lieu de les faire de 6 pieds d’épaiſſeur & </s> <s xml:id="echoid-s8075" xml:space="preserve">de <lb/>4 de longueur, leur donner 6 pieds de queuë & </s> <s xml:id="echoid-s8076" xml:space="preserve">4 d’épaiſſeur, parce <lb/>qu’alors le bras de levier devenant plus long, la puiſſance reſiſtante <lb/>ſoutien droit beaucoup mieux la pouſſée de la Voûte; </s> <s xml:id="echoid-s8077" xml:space="preserve">& </s> <s xml:id="echoid-s8078" xml:space="preserve">comme <lb/>on ne ſauroit avoir un trop grand nombre de points d’apui, il ſe-<lb/>roit à propos, au lieu de quatre contreforts, d’en faire cinq de cha-<lb/>que côté, & </s> <s xml:id="echoid-s8079" xml:space="preserve">en ce cas il ſuffiroit de donner 6 pieds ou 6 & </s> <s xml:id="echoid-s8080" xml:space="preserve">demi <lb/>d’épaiſſeur aux pieds droits, puiſque ces contreforts étant ainſi diſ-<lb/>tribués, ils cauſeroient une reſiſtance d’environ un tiers au-deſſus <lb/>de celle qu’il faudroit, pour ſoutenir l’effort de la Voûte.</s> <s xml:id="echoid-s8081" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8082" xml:space="preserve">Les piés-droits & </s> <s xml:id="echoid-s8083" xml:space="preserve">les contreforts n’ayant que peu d’élevation, & </s> <s xml:id="echoid-s8084" xml:space="preserve"><lb/>bien liés avec leurs fondemens, on peut regarder les points d’apuis <lb/>placés ſous l’extremité des fondemens de la queuë des contreforts, <lb/>& </s> <s xml:id="echoid-s8085" xml:space="preserve">non pas au rez-de-Chauſſée comme nous l’avons ſupoſé dans le <lb/>deuxiéme Livre: </s> <s xml:id="echoid-s8086" xml:space="preserve">c’eſt pourquoi, afin d’allonger encore plus le bras <lb/>de levier, je voudrois qu’on donnât beaucoup d’empatement aux <lb/>fondemens, les faiſant deborder de 2 pieds ou 2 & </s> <s xml:id="echoid-s8087" xml:space="preserve">demi, au-delà <lb/>du nud du mur, ramené au rez-de-Chauſſée par pluſieurs retraites, <lb/>comme on le voit par le cinquiéme deſſein de la 27 Planche, où <lb/> <anchor type="note" xlink:label="note-0380-01a" xlink:href="note-0380-01"/> l’on remarquera que, pour aſſurer les points d’apuis, on les a éta-<lb/>blis ſur deux rangs de madriers; </s> <s xml:id="echoid-s8088" xml:space="preserve">on ne feroit pas mal d’en mettre <lb/>auſſi ſous les fondemens des longs côtés, afin de prevenir l’inega-<lb/>lité des affaiſſemens: </s> <s xml:id="echoid-s8089" xml:space="preserve">cette conſtruction ſeroit excellente, ſur-<lb/>tout dans un mauvais terrain, parce qu’il ſuffiroit de s’y aprofondir <lb/>de 5 à 6 pieds; </s> <s xml:id="echoid-s8090" xml:space="preserve">& </s> <s xml:id="echoid-s8091" xml:space="preserve">je puis bien aſſeurer que la dépenſe ne ſeroit pas <pb o="67" file="0381" n="407" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> ſi conſiderable à beaucoup près, que ſi l’on donnoit 8 à 9 pieds <lb/>d’épaiſſeur aux longs côtés comme à l’ordinaire.</s> <s xml:id="echoid-s8092" xml:space="preserve"/> </p> <div xml:id="echoid-div361" type="float" level="3" n="4"> <note position="left" xlink:label="note-0380-01" xlink:href="note-0380-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>27. <lb/><emph style="sc">Fig</emph>. 5.</note> </div> <p> <s xml:id="echoid-s8093" xml:space="preserve">La principale cauſe, qui rend les planchers des Magaſins fort <lb/>humides, & </s> <s xml:id="echoid-s8094" xml:space="preserve">qui fait qu’ils ſe pourriſſent au bout d’un certain tems, <lb/>c’eſt que l’on a coûtume de poſer les lambourdes ſur la terre, & </s> <s xml:id="echoid-s8095" xml:space="preserve"><lb/>de remplir leur intervalle de recoupes de pierre, ou de charbon; <lb/></s> <s xml:id="echoid-s8096" xml:space="preserve">ainſi, l’air ne pouvant circuler par le deſſous du plancher, les ma-<lb/>driers ſe pourriſſent: </s> <s xml:id="echoid-s8097" xml:space="preserve">or, pour prévenir cet inconvenient, je vou-<lb/>drois que l’on fit la derniere retraite interieure des fondemens <lb/>d’environ un pied plus élevé que le rez-de-Chauſſée du pourtour ex-<lb/>terieur du Magaſin, & </s> <s xml:id="echoid-s8098" xml:space="preserve">qu’on lui donnât 5 ou 6 pouces de largeur, <lb/>& </s> <s xml:id="echoid-s8099" xml:space="preserve">traverſer enſuite toute la longueur du Magaſin, par trois dez de <lb/>Maçonnerie, également eſpacés les uns des autres, leur donnant <lb/>un pied de hauteur ſur autant d’épaiſſeur, fondés ſur 3 ou 4 rangs <lb/>de briques poſées à plat.</s> <s xml:id="echoid-s8100" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8101" xml:space="preserve">Après que cette Maçonnerie ſera bien arraſée à la hauteur de <lb/>la retraite interieure, & </s> <s xml:id="echoid-s8102" xml:space="preserve">qu’elle aura eu le tems de ſecher, il <lb/>faut la traverſer par des lambourdes, qui iront ſe terminer ſur les <lb/>retraites des longs côtés, obſervant de les placer à 2 pieds de diſ-<lb/>tance, de milieu en milieu; </s> <s xml:id="echoid-s8103" xml:space="preserve">&</s> <s xml:id="echoid-s8104" xml:space="preserve">, pour que la Maçonnerie ne les en-<lb/>dommage pas, il eſt bon mettre entre deux des couſſinets ou <lb/>bouts de madriers, d’un pouce & </s> <s xml:id="echoid-s8105" xml:space="preserve">demi ou deux pouces d’épaiſſeur.</s> <s xml:id="echoid-s8106" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8107" xml:space="preserve">Toutes les lambourdes étant bien arraſées, on poſera le premier <lb/>& </s> <s xml:id="echoid-s8108" xml:space="preserve">le ſecond plancher comme à l’ordinaire, bien chevillé; </s> <s xml:id="echoid-s8109" xml:space="preserve">& </s> <s xml:id="echoid-s8110" xml:space="preserve">com-<lb/>me l’entrevoux des poutrelles, auſſi bien que l’intervalle des dez, <lb/>ſur leſquelles elles ſeront poſées, ne ſera rempli par aucune ma-<lb/>tiere, il faudra, afin que l’air puiſſe y circuler, & </s> <s xml:id="echoid-s8111" xml:space="preserve">rafraichiſſe le deſ-<lb/>ſous du plancher, pratiquer dans le plancher même, le long de <lb/>chaque pignon, des trous ou évents d’un pied en quarré, enſorte <lb/>qu’il s’en trouve deux, aux extremités de chaque eſpace vuide qui <lb/>y regne.</s> <s xml:id="echoid-s8112" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8113" xml:space="preserve">Pour avoir une parfaite intelligence de ce qne je viens de dire, <lb/>il ſuffira de conſiderer avec un peu d’attention le plan & </s> <s xml:id="echoid-s8114" xml:space="preserve">le pro-<lb/>fil repreſenté par la 5<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8115" xml:space="preserve">& </s> <s xml:id="echoid-s8116" xml:space="preserve">la 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8117" xml:space="preserve">Figure de la Planche 27, où l’on <lb/> <anchor type="note" xlink:label="note-0381-01a" xlink:href="note-0381-01"/> verra que le plancher du Magaſin eſt partagé en deux parties: </s> <s xml:id="echoid-s8118" xml:space="preserve">l’u-<lb/> <anchor type="note" xlink:label="note-0381-02a" xlink:href="note-0381-02"/> ne fait voir la diſpoſition des dez de Maçonnerie, & </s> <s xml:id="echoid-s8119" xml:space="preserve">des lambour-<lb/>des, & </s> <s xml:id="echoid-s8120" xml:space="preserve">l’autre en quel ſens ces lambourdes ſont recouvertes par <lb/>les madriers; </s> <s xml:id="echoid-s8121" xml:space="preserve">ainſi, je ne m’y arrêterai pas davantage.</s> <s xml:id="echoid-s8122" xml:space="preserve"/> </p> <div xml:id="echoid-div362" type="float" level="3" n="5"> <note position="right" xlink:label="note-0381-01" xlink:href="note-0381-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>27.</note> <note position="right" xlink:label="note-0381-02" xlink:href="note-0381-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 5. <lb/>& 6.</note> </div> <p> <s xml:id="echoid-s8123" xml:space="preserve">En compoſant ce Chapitre, j’ai cherché à reſoudre une diffi-<lb/>culté qui s’eſt preſentée pluſieurs fois à mon eſprit; </s> <s xml:id="echoid-s8124" xml:space="preserve">ſavoir comme <lb/>il falloit déterminer l’épaiſſeur des Voûtes des Magaſins, celle des <pb o="68" file="0382" n="408" rhead="LA SCIENCE DES INGENIEURS,"/> Souterrains, & </s> <s xml:id="echoid-s8125" xml:space="preserve">de tous autres édifices militaires, ſelon leur differente <lb/>grandeur, pour qu’elle reſiſte également au choc des Bombes: </s> <s xml:id="echoid-s8126" xml:space="preserve">il eſt <lb/>vrai que nous ſommes prévenus, qu’une Voûte en plain ceintre, de <lb/>25 pieds de largeur & </s> <s xml:id="echoid-s8127" xml:space="preserve">de 3 pieds d’épaiſſeur dans le milieu des reins, <lb/>eſt parfaitement à l’épreuve; </s> <s xml:id="echoid-s8128" xml:space="preserve">mais, nous ignorons quelle dimenſion <lb/>il faut donner à celle qui auroit plus ou moins de largeur, car il <lb/>n’y a point de doute, qu’il ne faille regler l’épaiſſeur à proportion, <lb/>& </s> <s xml:id="echoid-s8129" xml:space="preserve">c’eſt ce que l’on pourra faire en ſuivant la regle que voici.</s> <s xml:id="echoid-s8130" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8131" xml:space="preserve">Voulant conſtruire un Magaſin de 36 pieds de largeur, couvert <lb/>par une Voûte en plain ceintre; </s> <s xml:id="echoid-s8132" xml:space="preserve">on demande quelle épaiſſeur il faut <lb/>lui donner dans le milieu des reins, pour qu’elle ſoit à l’épreuve: </s> <s xml:id="echoid-s8133" xml:space="preserve">il <lb/>faut dire, ſi le diamétre de 25 pieds donne 9 pour le quarré de l’épaiſſeur <lb/>de la Voûte qui eſt à l’épreuve, qui donnera 36 pieds diamétre d’une <lb/>autre Voûte, pour le quarré de ſon épaiſſeur, afin qn’elle ſoit auſſi à <lb/>l’épreuve; </s> <s xml:id="echoid-s8134" xml:space="preserve">on trouvera environ 13 pieds, dont la racine quarrée, <lb/>qui eſt 3 pieds 7 pouces 2 lignes, ſera au juſte l’épaiſſeur que l’on <lb/>demande, & </s> <s xml:id="echoid-s8135" xml:space="preserve">ainſi des autres.</s> <s xml:id="echoid-s8136" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8137" xml:space="preserve">Si l’on fait attention, que le principe que nous avons inſinué, au <lb/>ſujet de la reſiſtance des bois, dans le deuxiéme Chapitre de ce <lb/>quatriéme Livre, peut s’apliquer à celle des Voûtes, on apercevra <lb/>ſans peine la demonſtration de cette regle; </s> <s xml:id="echoid-s8138" xml:space="preserve">c’eſt pourquoi je ne m’y <lb/>arrêterai pas, pour ne point faire une trop longue digreſſion: </s> <s xml:id="echoid-s8139" xml:space="preserve">je <lb/>dirai ſeulement, qu’on pourra trouver de la même maniere la lon-<lb/>gueur des vouſſoirs pour les arches des Ponts, de telle grandeur <lb/>que l’on voudra, comme j’en ferai mention dans le ſecond volume.</s> <s xml:id="echoid-s8140" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8141" xml:space="preserve">Quand on conſtruit des Magaſins ſur des lieux élevés, & </s> <s xml:id="echoid-s8142" xml:space="preserve">qu’on <lb/>peut pratiquer au-deſſous de leur rez-de-Chauſſée des Souterrains <lb/>pour renfermer des munitions de guerre ou de bouche, on leur <lb/>donne la diſpoſition quel’on voit repreſentée par le 3<emph style="sub">e</emph> & </s> <s xml:id="echoid-s8143" xml:space="preserve">le 4<emph style="sub">e</emph> deſſein <lb/> <anchor type="note" xlink:label="note-0382-01a" xlink:href="note-0382-01"/> de la 26<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8144" xml:space="preserve">Planche, où l’on obſervera que le Souterrain eſt couvert <lb/>par pluſieurs Voûtes d’arrête, pour éviter l’élevation qu’il auroit <lb/> <anchor type="note" xlink:label="note-0382-02a" xlink:href="note-0382-02"/> fallu lui donner, ſi on avoit voulu le faire autrement; </s> <s xml:id="echoid-s8145" xml:space="preserve">on remarque-<lb/>ra auſſi que les contreforts ſe trouvent placés vis-à-vis les pilliers, <lb/>qui ſoutiennent les Voûtes dans le milieu des ſouterrains, parce <lb/>qu’ainſi ils buttent toute l’action de la pouſſée, qui dans ces ſortes <lb/>de Voûtes aboutit au point où ſe rencontrent les arrêtes ou dia-<lb/>gonalles: </s> <s xml:id="echoid-s8146" xml:space="preserve">comme ces Voûtes ſont garanties du principal effort de <lb/>la bombe, par celle qui couvre le Magaſin qui eſt au-deſſus, il <lb/>ſuffit de leur donner deux pieds d’épaiſſeur, à l’endroit de la clef <lb/>pour être parfaitement à l’épreuve.</s> <s xml:id="echoid-s8147" xml:space="preserve"/> </p> <div xml:id="echoid-div363" type="float" level="3" n="6"> <note position="left" xlink:label="note-0382-01" xlink:href="note-0382-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>26.</note> <note position="left" xlink:label="note-0382-02" xlink:href="note-0382-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 3. <lb/>& 4.</note> </div> <p> <s xml:id="echoid-s8148" xml:space="preserve">L’on deſcend dans le ſouterrain par un eſcalier que l’on voit <pb file="0383" n="409"/> <pb file="0383a" n="410"/> <anchor type="figure" xlink:label="fig-0383a-01a" xlink:href="fig-0383a-01"/> <pb file="0384" n="411"/> <pb o="69" file="0385" n="412" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> marqué ſur le plan, & </s> <s xml:id="echoid-s8149" xml:space="preserve">c’eſt dans le pignon qui répond à la rampe <lb/>que l’on pratique un évent ou petite fenêtre, pour lui donner de <lb/>l’air: </s> <s xml:id="echoid-s8150" xml:space="preserve">l’on pourroit même faire des ſoupiraux entre les contreforts, <lb/>pour le rendre moins humide; </s> <s xml:id="echoid-s8151" xml:space="preserve">mais il faudroit qu’ils fuſſent tour-<lb/>nez de façon à ne cauſer aucun préjudice.</s> <s xml:id="echoid-s8152" xml:space="preserve"/> </p> <div xml:id="echoid-div364" type="float" level="3" n="7"> <figure xlink:label="fig-0383a-01" xlink:href="fig-0383a-01a"> <image file="0383a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0383a-01"/> </figure> </div> <p> <s xml:id="echoid-s8153" xml:space="preserve">Comme l’étage du rez-de-Chauſſée n’eſt autre choſe qu’un Ma-<lb/>gaſin ordinaire, qui ne conprend rien de particulier, je ne m’y <lb/>arrêterai pas, non plus qu’aux dimenſions qu’il convient de donner <lb/>aux piés-droits, en ayant aſſez dit ſur ce ſujet dans le ſecond Livre.</s> <s xml:id="echoid-s8154" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8155" xml:space="preserve">Dans pluſieurs de nos Places, on voit des Edifices executés com-<lb/>me le précedent; </s> <s xml:id="echoid-s8156" xml:space="preserve">il s’en trouve même de plus conſiderables, com-<lb/>me on en peut juger par le profil repreſenté par la 3<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8157" xml:space="preserve">Figure de la <lb/>27<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8158" xml:space="preserve">Planche, qui apartient à un Arſenal compoſé de quatre étages: <lb/></s> <s xml:id="echoid-s8159" xml:space="preserve"> <anchor type="note" xlink:label="note-0385-01a" xlink:href="note-0385-01"/> le premier eſt un ſouterrain couvert par deux Voûtes en plain cein-<lb/> <anchor type="note" xlink:label="note-0385-02a" xlink:href="note-0385-02"/> tre, qui s’apuyent mutuellement ſur le mur de refend, qui partage <lb/>le ſouterrain en deux, dans toute ſa longueur: </s> <s xml:id="echoid-s8160" xml:space="preserve">on y a percé des <lb/>portes de diſtance en diſtance, pour paſſer d’un ſouterrain à l’autre, <lb/>ce que je n’ai pû exprimer ſur le plan, n’en ayant raporté qu’un bout <lb/>repreſenté par la 4<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8161" xml:space="preserve">Figure, à cauſe qu’il auroit fallu trop d’eſpace <lb/>pour le faire voir tout entier; </s> <s xml:id="echoid-s8162" xml:space="preserve">mais un pareil plan eſt ſi ſimple, qu’on <lb/>s’imaginera aiſément de quoi il eſt queſtion: </s> <s xml:id="echoid-s8163" xml:space="preserve">d’ailleurs, la longueur eſt <lb/>en quelque façon indéterminée, puiſqu’elle dépend de la place où <lb/>l’on voudroit conſtruire un édifice comme celui-là, de la dépenſe <lb/>qu’on y veut faire, ou du beſoin de l’avoir plus ou moins étendu; </s> <s xml:id="echoid-s8164" xml:space="preserve">j’a-<lb/>joûterai ſeulement, qu’il convient de deſcendre dans cesſortes de ſou-<lb/>terrains par une rampe large & </s> <s xml:id="echoid-s8165" xml:space="preserve">commode, ainſi qu’on le fait aux <lb/>écuries qui ſont pratiquées dans les caves, plûtôt que par un eſca-<lb/>lier, afin de pouvoir manœuvrer plus aiſément, quand il s’agit d’y <lb/>introduire des munitions de guerre ou de bouche.</s> <s xml:id="echoid-s8166" xml:space="preserve"/> </p> <div xml:id="echoid-div365" type="float" level="3" n="8"> <note position="right" xlink:label="note-0385-01" xlink:href="note-0385-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>27.</note> <note position="right" xlink:label="note-0385-02" xlink:href="note-0385-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s8167" xml:space="preserve">Ce ſouterrain étant ſupoſé creuſé dans le roc, on a pris occaſion <lb/>de montrer comme en pareil cas on peut ſe diſpenſer de faire les <lb/>murs auſſi épais en bas qu’en haut, en les apuyant contre le roc qui <lb/>doit faire partie de l’épaiſſeur qu’il auroit fallu donner dans tout au-<lb/>tre terrain, puiſqu’il ſuffit de le couper par reſſaut, & </s> <s xml:id="echoid-s8168" xml:space="preserve">de ſuivre <lb/>ce qui a été enſeigné dans le 3<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8169" xml:space="preserve">Livre, en faiſant mention des fon-<lb/>demens établis dans ce goût-là.</s> <s xml:id="echoid-s8170" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8171" xml:space="preserve">Le ſecond étage, qui eſt celui du rez-de-Chauſſée, eſt à peu près <lb/>ſemblable au précédent, étant auſſi voûté en plain ceintre à l’épreu-<lb/>ve de la Bombe; </s> <s xml:id="echoid-s8172" xml:space="preserve">ce qui peut être d’un grand avantage dans les pe-<lb/>tites fortereſſes eſcarpées, & </s> <s xml:id="echoid-s8173" xml:space="preserve">qui ſont plus ſujetets à être inquietées <lb/>des Bombes que du Canon.</s> <s xml:id="echoid-s8174" xml:space="preserve"/> </p> <pb o="70" file="0386" n="413" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s8175" xml:space="preserve">Le troiſiéme étage peut ſervir pourles farines ou des munitions de <lb/>guerre, & </s> <s xml:id="echoid-s8176" xml:space="preserve">le 4<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8177" xml:space="preserve">de Salle d’Armes; </s> <s xml:id="echoid-s8178" xml:space="preserve">je crois même quel’Arſenal de <lb/>Charlemont a été bâti à peu près ſelon le deſſein queje viens d’ex-<lb/>pliquer: </s> <s xml:id="echoid-s8179" xml:space="preserve">puiſque nous en ſommes ſur les Arſenaux, il eſt à propos <lb/>de traiter ce ſujet un peu plus amplement, par raport à la conſe-<lb/>quence des Places où on les conſtruit, & </s> <s xml:id="echoid-s8180" xml:space="preserve">à pluſieurs circonſtances <lb/>qu’il eſt neceſſaire de détailler.</s> <s xml:id="echoid-s8181" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8182" xml:space="preserve">Il n’y a pas de Place de Guerre oùil ne faille un Arſenal: </s> <s xml:id="echoid-s8183" xml:space="preserve">ſa gran-<lb/>deur & </s> <s xml:id="echoid-s8184" xml:space="preserve">ſa diſtribution doivent être aſſujetties à la conſequence du <lb/>lieu, & </s> <s xml:id="echoid-s8185" xml:space="preserve">aux travaux qu’on pourra y faire; </s> <s xml:id="echoid-s8186" xml:space="preserve">par exemple, aux Citadel-<lb/>les & </s> <s xml:id="echoid-s8187" xml:space="preserve">autres petites fortereſſes, il ſuffit d’en avoir un d’une gran-<lb/>deur mediocre, pour contenir les munitions deſtinées à la défenſe, <lb/>au lieu que dans une Ville frontiere conſiderable, il en faut un grand <lb/>pour y former des équipages de campagne, qui comprenne tous les <lb/>endroits neceſſaires à executer les ouvrages propres à l’artillerie.</s> <s xml:id="echoid-s8188" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8189" xml:space="preserve">Il faut qu’un Arſenal de conſequence ſoit bâti, ſi cela ſe peut, dans <lb/>le voiſinage d’une riviere capable de porter batteaux, & </s> <s xml:id="echoid-s8190" xml:space="preserve">qu’un bras <lb/>de cette riviere reponde à un baſſin dans l’enceinte de l’Arſenal <lb/>même pour y charger trois ou quatre batteaux à la fois, de manie-<lb/>re que les habitans ne puiſſent être inſtruits de la quantité des mu-<lb/>nitions dont le convoi eſt compoſé, non plus que de leurs qualités.</s> <s xml:id="echoid-s8191" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8192" xml:space="preserve">Le corps propre de l’Arſenal, ſervant à garder les principales mu-<lb/>nitions, doit être conſtruit dans l’étenduë d’une grande cour, en-<lb/>tourée de bâtimens: </s> <s xml:id="echoid-s8193" xml:space="preserve">ce corps doit avoir auſſi ſa cour particuliere, <lb/>environnée de couverts, ſeparés par autant de cloiſons qu’il ſera <lb/>neceſſaire, pour les differentes eſpeces de munitions; </s> <s xml:id="echoid-s8194" xml:space="preserve">par exemple, <lb/>s’il y a une fonderie dans la Place, on prendra une ſalle pour les <lb/>metaux, une autre pour le fer, une pour le charbon, une autre <lb/>pour les plombs, grenades, petits boulets, cartouches, pierres à <lb/>fuſil, & </s> <s xml:id="echoid-s8195" xml:space="preserve">autres munitions peſantes: </s> <s xml:id="echoid-s8196" xml:space="preserve">on reſervera un eſpace près <lb/>de l’une des portes, pour la balance, où on mettra des ratelliers <lb/>pour les armes, des piéces dont on peut avoir beſoin, quelque <lb/>cordage, outils dont l’uſage eſt frequent; </s> <s xml:id="echoid-s8197" xml:space="preserve">& </s> <s xml:id="echoid-s8198" xml:space="preserve">il eſt bon que les me-<lb/>taux, fer & </s> <s xml:id="echoid-s8199" xml:space="preserve">charbon, ne ſoient pas éloignés de cette balance.</s> <s xml:id="echoid-s8200" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8201" xml:space="preserve">Le premier étage du grand corps de l’Arſenal doit ’avoir ſon <lb/>plancher voûté ſur poutrelles, & </s> <s xml:id="echoid-s8202" xml:space="preserve">ſervira pour les Salles d’Armes, <lb/>dans leſquelles il ſeroit à propos d’avoir des armoires, pour enfer-<lb/>mer pluſieurs petites munitions ſujettes à être priſes.</s> <s xml:id="echoid-s8203" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8204" xml:space="preserve">Le ſecond ſervira à mettre les armes des piéces de reſerve, ſacs <lb/>à terre, meſures, cordages, leviers, coins de mire, chapiteaux, <lb/>fuſées à Bombes & </s> <s xml:id="echoid-s8205" xml:space="preserve">à Grenades, marches d’outils, & </s> <s xml:id="echoid-s8206" xml:space="preserve">quantité d’au- <pb file="0387" n="414"/> <pb file="0387a" n="415"/> <anchor type="figure" xlink:label="fig-0387a-01a" xlink:href="fig-0387a-01"/> <pb file="0388" n="416"/> <pb o="71" file="0389" n="417" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> tres choſes, dont le poids n’eſt pas conſiderable.</s> <s xml:id="echoid-s8207" xml:space="preserve"/> </p> <div xml:id="echoid-div366" type="float" level="3" n="9"> <figure xlink:label="fig-0387a-01" xlink:href="fig-0387a-01a"> <image file="0387a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0387a-01"/> </figure> </div> <p> <s xml:id="echoid-s8208" xml:space="preserve">Le grenier au-deſſus pourra ſervir de décharge à ce qu’il y au-<lb/>ra de trop dans l’étage au-deſſous; </s> <s xml:id="echoid-s8209" xml:space="preserve">on y placera les munitions le-<lb/>geres, comme les harnois des chevaux d’Artillerie, les hottes & </s> <s xml:id="echoid-s8210" xml:space="preserve"><lb/>paniers.</s> <s xml:id="echoid-s8211" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8212" xml:space="preserve">L’avant-Cour comprendra les logemens des Officiers d’Artille-<lb/>rie, auſſi-bien que ceux des ouvriers: </s> <s xml:id="echoid-s8213" xml:space="preserve">ces logemens doivent être <lb/>de deux étages diſtribués ſuivant les commodités qu’on y pourra <lb/>pratiquer, prenant garde qu’il n’y ait point de fenêtres qui donnent <lb/>ſur les ruës voiſines de l’Arſenal; </s> <s xml:id="echoid-s8214" xml:space="preserve">pour les couverts, il faut les diſ-<lb/>tribuer de façon qu’on quiſſe y pratiquer des Forges, des Boutiques <lb/>d’Armuriers, des Attelliers pour les Charpentiers & </s> <s xml:id="echoid-s8215" xml:space="preserve">les Charrons, <lb/>enfin pour tous les Charrois, parce qu’on ſupoſe que dans l’étage <lb/>du rez-de-Chauſſée du grand Corps de l’Arſenal, on y mettra <lb/>tous les bois.</s> <s xml:id="echoid-s8216" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8217" xml:space="preserve">Mais, pour avoir une idée des differentes choſes qui conviennent <lb/> <anchor type="note" xlink:label="note-0389-01a" xlink:href="note-0389-01"/> à un Arſenal, il n’y a qu’à conſiderer celui du Mont-Royal, que j’ai <lb/>raporté ſur la 31 planche, comme un des plus magnifiques de tous <lb/>ceux qu’on a bâti dans les Places du Roy; </s> <s xml:id="echoid-s8218" xml:space="preserve">c’eſt pourquoi j’ai mieux <lb/>aimé le donner pour exemple, que d’en faire un ſelon mon idée, <lb/>c’eſt-à-dire qui eut raport à ce que je viens d’inſinuer.</s> <s xml:id="echoid-s8219" xml:space="preserve"/> </p> <div xml:id="echoid-div367" type="float" level="3" n="10"> <note position="right" xlink:label="note-0389-01" xlink:href="note-0389-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>31.</note> </div> <p> <s xml:id="echoid-s8220" xml:space="preserve">Il ſe fait encore des Arſenaux compoſés d’une grande Cour, à l’en-<lb/>tour de laquelle il y a des Arcades pour mettre à couvert tous les <lb/>bois propres à l’Artillerie, les Affuts & </s> <s xml:id="echoid-s8221" xml:space="preserve">les autres Charrois neceſſaires <lb/>au Canon, & </s> <s xml:id="echoid-s8222" xml:space="preserve">au-deſſus de ces Arcades ſont les Salles d’Armes, & </s> <s xml:id="echoid-s8223" xml:space="preserve"><lb/>les autres où l’on renferme les munitions; </s> <s xml:id="echoid-s8224" xml:space="preserve">& </s> <s xml:id="echoid-s8225" xml:space="preserve">tel eſt, par exemple, <lb/>l’Arſenal de la Ferre.</s> <s xml:id="echoid-s8226" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8227" xml:space="preserve">Il me reſte, pour finir ce Chapitre, de faire mention des Fonde-<lb/>ries pour le Canon, dont je ne donnerai qu’une idée ſeulement, <lb/>parce que je me propoſe d’en parler avec plus de détail dans un <lb/>Ouvrage qui regardera particulierement l’Artillerie; </s> <s xml:id="echoid-s8228" xml:space="preserve">ainſi, il ſuffira <lb/>de jetter les yeux ſur la 28 planche, pour y avoir marqué tous les <lb/> <anchor type="note" xlink:label="note-0389-02a" xlink:href="note-0389-02"/> lieux neceſſaires à une Fonderie. </s> <s xml:id="echoid-s8229" xml:space="preserve">Celle que je raporte a été projettée <lb/>pour la Fere, mais elle n’a pas eu lieu, à cauſe des obſtacles qu’on <lb/>a rencontré de la part du terrain: </s> <s xml:id="echoid-s8230" xml:space="preserve">car, ce qu’il y a de plus conſi-<lb/>derable dans un pareil Edifice, ce ſont les Fourneaux & </s> <s xml:id="echoid-s8231" xml:space="preserve">les Foſſes <lb/>dans leſquelles on coule la Fonte pour la Fabrique du Canon; </s> <s xml:id="echoid-s8232" xml:space="preserve">& </s> <s xml:id="echoid-s8233" xml:space="preserve"><lb/>comme il faut que les Foſſes ſoient d’une certaine profondeur, on <lb/>a trouvé que la Fere étoit un lieu trop aquatique: </s> <s xml:id="echoid-s8234" xml:space="preserve">cela n’empêche <lb/>pas que ce projet ne ſoit parfaitement bien entendu, & </s> <s xml:id="echoid-s8235" xml:space="preserve">ne puiſſe <lb/>être quelque jour executé ailleurs.</s> <s xml:id="echoid-s8236" xml:space="preserve"/> </p> <div xml:id="echoid-div368" type="float" level="3" n="11"> <note position="right" xlink:label="note-0389-02" xlink:href="note-0389-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>82.</note> </div> <pb o="72" file="0390" n="418" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div370" type="section" level="2" n="122"> <head xml:id="echoid-head274" xml:space="preserve">CHAPITRE DIXIE’ME. <lb/>Des Cazernes, de l’Hôpital, de la Priſon, & Maiſons de <lb/>Bourgeois.</head> <p> <s xml:id="echoid-s8237" xml:space="preserve">POUR maintenir l’ordre & </s> <s xml:id="echoid-s8238" xml:space="preserve">la diſcipline dans la Garniſon <lb/>des Places, on y fait des Cazernes pour loger les Troupes; <lb/></s> <s xml:id="echoid-s8239" xml:space="preserve">& </s> <s xml:id="echoid-s8240" xml:space="preserve">on s’en eſt ſi bien trouvé, qu’il y a peu d’endroits où l’on n’en <lb/>ait conſtruit: </s> <s xml:id="echoid-s8241" xml:space="preserve">en effet, l’experience fait voir que les Garniſons qui <lb/>ſont cazernées ſont beaucoup plus tranquiles, à cauſe de la com-<lb/>modité que les bas Officiers ont de faire l’apel tous les ſoirs, ce <lb/>qui ne peut ſe pratiquer exactement quand le Soldat eſt diſperſé <lb/>chez les Bourgeois où il a la liberté de ſortir à toute heure de la <lb/>nuit. </s> <s xml:id="echoid-s8242" xml:space="preserve">Un autre inconvenient, c’eſt qu’un Gouverneur, ou un Com-<lb/>mandant de Place, ne peut en tems de Guerre faire ſortir un Corps <lb/>de Troupes, ou le moindre Parti, ſans que toute Ville n’en ſoit in-<lb/>formée. </s> <s xml:id="echoid-s8243" xml:space="preserve">S’il arrive quelque allarme, on n’aſſemble la Garniſon qu’a-<lb/>vec beaucoup de peine & </s> <s xml:id="echoid-s8244" xml:space="preserve">de tems, au lieu que dans les Cazernes <lb/>on fait faire ſur le champ toutes les diſpoſitions que le Service du <lb/>Roy peut demander.</s> <s xml:id="echoid-s8245" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8246" xml:space="preserve">Les Cazernesſe conſtruiſent depluſieurs façons, ſelon la ſituation <lb/>de l’endroit quileur eſt deſtiné. </s> <s xml:id="echoid-s8247" xml:space="preserve">Quand on a un eſpace aſſez étendu <lb/>pour faire une grande Cour entourrée de Bâtimens, elles ſont fort <lb/>commodes, parce qu’elles ſe ferment d’elles-mêmes, & </s> <s xml:id="echoid-s8248" xml:space="preserve">queles cham-<lb/>bres étant plus ramaſſées, on peut en moins de tems faire execu-<lb/>ter les ordres que le Gouverneur ou le Commandant de la Troupe <lb/>juge à propos de donner.</s> <s xml:id="echoid-s8249" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8250" xml:space="preserve">Cette diſpoſition de Cazernes convient ſur-tout à la Cavalerie, <lb/>parce qu’elle a beſoin d’une Cour pour le ſervice journalier des <lb/>Chevaux; </s> <s xml:id="echoid-s8251" xml:space="preserve">alors on fait les Chambres au-deſſus des Ecuries & </s> <s xml:id="echoid-s8252" xml:space="preserve">un <lb/>Corridor pour communiquer de l’une à l’autre, qui regne tout au <lb/>tour du quartier; </s> <s xml:id="echoid-s8253" xml:space="preserve">ou bien, ſansfaire de Corridor, l’on pratique des <lb/>Eſcaliers de diſtance en diſtance: </s> <s xml:id="echoid-s8254" xml:space="preserve">mais, ils occupent beaucoup de <lb/>place mal-à-propos; </s> <s xml:id="echoid-s8255" xml:space="preserve">aulieu qu’ayant un Corridor, deux outrois Eſ-<lb/>caliers ſuffiſent: </s> <s xml:id="echoid-s8256" xml:space="preserve">il eſt vrai qu’il rend les Chambres du premier étage <lb/>un peu obſcures, comme on le remarque aux quartiers de Cavale-<lb/>rie qui ſont dans la plûpart des Villes de Flandres; </s> <s xml:id="echoid-s8257" xml:space="preserve">mais, on peut <lb/>remedier à cet inconvenient, en faiſant le Bâtiment moins écraſé que <lb/>ceux dont je parle.</s> <s xml:id="echoid-s8258" xml:space="preserve"/> </p> <pb file="0391" n="419"/> <pb file="0391a" n="420"/> <figure> <image file="0391a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0391a-01"/> </figure> <pb file="0392" n="421"/> <pb file="0393" n="422"/> <pb file="0393a" n="423"/> <figure> <image file="0393a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0393a-01"/> </figure> <pb file="0394" n="424"/> <pb o="73" file="0395" n="425" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s8259" xml:space="preserve">Quand les Cazernes ſe bâtiſſent le long du rempart vers les cour-<lb/>tines (comme Mr. </s> <s xml:id="echoid-s8260" xml:space="preserve">de Vauban l’a pratiqué en beaucoup d’endroits) <lb/>elles ſont compoſées d’un grand corps de Bâtiment pour loger les <lb/>Soldats, aux extrêmités duquel il y a des Pavillons pour les Offi-<lb/>ciers: </s> <s xml:id="echoid-s8261" xml:space="preserve">ces logemens ſont preſque toûjours à deux ou trois Etages, <lb/>ſans y comprendre le rez-de-Chauſſée.</s> <s xml:id="echoid-s8262" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8263" xml:space="preserve">Dans chaque corps de Cazerne double, l’on fait quatre Chambres <lb/>à chaque étage, dont deux repondront à l’Eſcalier qui eſt de leur <lb/>côté, & </s> <s xml:id="echoid-s8264" xml:space="preserve">les deux autres aux leurs: </s> <s xml:id="echoid-s8265" xml:space="preserve">chaque Chambre doit avoir <lb/>22 pieds de long dans œuvre ſur 18 de profondeur pour placer <lb/>4 lits; </s> <s xml:id="echoid-s8266" xml:space="preserve">celles du rez-de-Chauſſée doivent être élevées de 12 pieds, <lb/>celles du premier étage de 10, & </s> <s xml:id="echoid-s8267" xml:space="preserve">celles en galetas de 8, leurs portes <lb/>larges de 3 pieds ſur 6 de hauteur, & </s> <s xml:id="echoid-s8268" xml:space="preserve">les murs de face deux pieds <lb/>d’épaiſſeur au moins, avec un cordon à l’endroit du premier Plan-<lb/>cher & </s> <s xml:id="echoid-s8269" xml:space="preserve">une tablette ornée de moulure pour ſervir de couronne-<lb/>ment au-deſſus du ſecond plancher de la maniere qu’on le voit <lb/>marqué ſur la Planche 29. </s> <s xml:id="echoid-s8270" xml:space="preserve">qu’il ne faut qu’apercevoir pour enten-<lb/> <anchor type="note" xlink:label="note-0395-01a" xlink:href="note-0395-01"/> dre les deſſeins qu’elle répreſente.</s> <s xml:id="echoid-s8271" xml:space="preserve"/> </p> <div xml:id="echoid-div370" type="float" level="3" n="1"> <note position="right" xlink:label="note-0395-01" xlink:href="note-0395-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>29.</note> </div> <p> <s xml:id="echoid-s8272" xml:space="preserve">Quand on veut faire les Planchers des Cazernes voûtés ſur pou-<lb/>trelles, on taille ces poutrelles à cinq pans de 12 pouces de face <lb/>chacune, & </s> <s xml:id="echoid-s8273" xml:space="preserve">eſpacées de 18 à 20 pouces les unes des autres: </s> <s xml:id="echoid-s8274" xml:space="preserve">elles <lb/>doivent être poſées ſur des Sablieres de 4 à 8 pouces d’épaiſſeur en-<lb/>caſtrées dans les gros murs où elles doivent entrer d’environ 12 à <lb/>15 pouces; </s> <s xml:id="echoid-s8275" xml:space="preserve">on les revêtit d’un petit madrier de chêne ou de ſapin <lb/>de 2 à 3 pouces d’épaiſſeur, poſées en mortier de terre graſſe pour <lb/>empêcher que la Chaux ne conſomme le bois.</s> <s xml:id="echoid-s8276" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8277" xml:space="preserve">L’entrevoux de ces poutrelles ſe voûte de Briques miſes de cant <lb/>en bonne liaiſon & </s> <s xml:id="echoid-s8278" xml:space="preserve">en mortier de Chaux & </s> <s xml:id="echoid-s8279" xml:space="preserve">Sable: </s> <s xml:id="echoid-s8280" xml:space="preserve">on poſe en mor-<lb/>tier de terre graſſe le premier rang de briques qui touche le flanc <lb/>de ces poutrelles; </s> <s xml:id="echoid-s8281" xml:space="preserve">on arraſe bien le deſſus de la Voûte, & </s> <s xml:id="echoid-s8282" xml:space="preserve">on re-<lb/>cire ſeulement les joints ſans y faire aucun enduit, après quoi ſur <lb/>l’étendu de chaque Chambre on fait un pavé de Briques poſées <lb/>de plat à mortier fin.</s> <s xml:id="echoid-s8283" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8284" xml:space="preserve">On ne voûte plus guére ſur poutrelles, parce que cela charge trop <lb/>le bâtiment, on aime mieux faire les Planchers comme à l’ordinai-<lb/>re, en ce cas on ſe ſert de poutres proprement équarries à vive ar-<lb/>reſte de même que les ſolives qui doivent être de bois de brin de <lb/>5 à 7 pouces de gros poſés ſur leur fort & </s> <s xml:id="echoid-s8285" xml:space="preserve">eſpacés à un pied <lb/>de diſtance les uns des autres de milieu en milieu. </s> <s xml:id="echoid-s8286" xml:space="preserve">Si on ne fait <lb/>point un plancher double, on recouvre les ſoliveaux de planches <lb/>ſeiches d’un pouce & </s> <s xml:id="echoid-s8287" xml:space="preserve">demi d’épaiſſeur, aſſemblées à languettes &</s> <s xml:id="echoid-s8288" xml:space="preserve"> <pb o="74" file="0396" n="426" rhead="LA SCIENCE DES INGENIEURS,"/> rainure, blanchies des deux côtés,& </s> <s xml:id="echoid-s8289" xml:space="preserve">clouées chacune de trois cloux <lb/>à l’endroit de toutes les ſolives, dont l’un ſera mis au milieu de la <lb/>planche, & </s> <s xml:id="echoid-s8290" xml:space="preserve">les deux autres à 2 pouces près des joints; </s> <s xml:id="echoid-s8291" xml:space="preserve">obſervant <lb/>que ces planches ſoient poſées de maniere que leur extremité ne <lb/>ſe rencontre point de ſuite ſur une même ſolive, & </s> <s xml:id="echoid-s8292" xml:space="preserve">que le tout ſoit <lb/>bien mis de niveau, non-ſeulement avec le ſeuil des portes, mais <lb/>en tout autre ſens & </s> <s xml:id="echoid-s8293" xml:space="preserve">proprement executé.</s> <s xml:id="echoid-s8294" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8295" xml:space="preserve">On pourra auſſi faire des rainures dans le flanc de chaque ſolive <lb/>pour y couler enſuite des boſſes ou petits racineaux que l’on enve-<lb/>lope de terre petrie & </s> <s xml:id="echoid-s8296" xml:space="preserve">préparée avec de la paille, qu’on ſerrera à me-<lb/>ſure les uns contre les autres, ce qui formera un plat-fond plus ſourd <lb/>& </s> <s xml:id="echoid-s8297" xml:space="preserve">plus ſur contre les accidens du feu, on le crépira & </s> <s xml:id="echoid-s8298" xml:space="preserve">blanchira <lb/>enſuite pardeſſous, & </s> <s xml:id="echoid-s8299" xml:space="preserve">le deſſus ſera recouvert de planches, de <lb/>carreaux, ou de briques.</s> <s xml:id="echoid-s8300" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8301" xml:space="preserve">Les Cheminées doivent avoir 5 pieds de largeur ſur 4 de hauteur, <lb/>& </s> <s xml:id="echoid-s8302" xml:space="preserve">leurs tuyaux 3 pieds ſur 8 pouces: </s> <s xml:id="echoid-s8303" xml:space="preserve">quant à leur hauteur, il faut <lb/>qu’elle ſurmonte le faîte du comble de 3 ou 4 pieds, pour éviter la <lb/>fumée. </s> <s xml:id="echoid-s8304" xml:space="preserve">Quoiqu’il ſoit d’uſage de ne point faire de cheminées ſans <lb/>jambage, cependant comme l’experience fait voir la facilité avec <lb/>laquelle elles ſe détruiſent tous les jours, il vaut mieux ſoûtenir leur <lb/>manteau par de doubles conſoles de pierres de taille ſans piés-<lb/>droits.</s> <s xml:id="echoid-s8305" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8306" xml:space="preserve">Les portes ſeront ſuſpenduës avec des gonds qui auront été placés <lb/>en bâtiſſant, & </s> <s xml:id="echoid-s8307" xml:space="preserve">la queuë de ces gonds ſera gravée dans le deſſus <lb/>des pierres de taille où elle devra être miſe. </s> <s xml:id="echoid-s8308" xml:space="preserve">Les gonds à repos & </s> <s xml:id="echoid-s8309" xml:space="preserve"><lb/>les pivots de ceux des portes auront 15 lignes de diamêtre, ceux <lb/>des fenêtres 7 à 8, & </s> <s xml:id="echoid-s8310" xml:space="preserve">ſeront tous parfaitement ronds & </s> <s xml:id="echoid-s8311" xml:space="preserve">à plomb ſur <lb/>leur queuë, les œils de pantures ſeront également ronds & </s> <s xml:id="echoid-s8312" xml:space="preserve">préci-<lb/>ſement de la grandeur convenable.</s> <s xml:id="echoid-s8313" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8314" xml:space="preserve">La cage de l’Eſcalier doit être de 7 à 8 picds de largeur parta-<lb/>gée en deux par un mur de chifre qui ſoûtienne les rampes, les <lb/>degrés ſe font d’un pied de giron ſur 5 à 6 pouces de hauteur; </s> <s xml:id="echoid-s8315" xml:space="preserve">& </s> <s xml:id="echoid-s8316" xml:space="preserve"><lb/>l’on fait deux pailliers, l’un au retour du milieu de la rampe & </s> <s xml:id="echoid-s8317" xml:space="preserve"><lb/>l’autre à chaque étage pour communiquer d’une Chambre à l’autre.</s> <s xml:id="echoid-s8318" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8319" xml:space="preserve">Supoſant qu’en chaque Chambre il y ait quatre lits, on pourra <lb/>y loger douze ſoldats, ſavoir huit dans la Chambre & </s> <s xml:id="echoid-s8320" xml:space="preserve">quatre de <lb/>garde; </s> <s xml:id="echoid-s8321" xml:space="preserve">ainſi dans les quatre Chambres de plain-pied on y logera 48 <lb/>hommes, & </s> <s xml:id="echoid-s8322" xml:space="preserve">dans un corps qui compoſe les douze Chambres qui <lb/>accompagnent les Eſcaliers, on pourra y en loger 144.</s> <s xml:id="echoid-s8323" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8324" xml:space="preserve">Le rez-de-Chauſſée des Cazernes, dont nous parlons, eſt prin-<lb/>cipalement deſtiné pour ſervir d’Ecurie, lorſque ces Cazernes ſe- <pb o="75" file="0397" n="427" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> roient occupées par la Cavalerie, c’eſt pourquoi on n’y a point per-<lb/>cé de fenêtres, n’étant éclairées que par le jour qu’elles peuvent ti-<lb/>rer du deſſus des portes, ainſi qu’on le voit dans l’élevation, ce qui <lb/>fait que ces chambres ne ſeroient pas fort commodes pour l’Infan-<lb/>terie; </s> <s xml:id="echoid-s8325" xml:space="preserve">mais je n’ai rien voulu y changer, parce qu’on en va voir <lb/>d’autres qui n’ont pas le même défaut.</s> <s xml:id="echoid-s8326" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8327" xml:space="preserve">Pour diſtribuer le logement des Officiers qui ſont dans les Pa-<lb/> <anchor type="note" xlink:label="note-0397-01a" xlink:href="note-0397-01"/> villons, il faut faire deux eſcaliers qui paſſent par le milieu, avec <lb/>un corridor de 6 pieds de large, qui traverſe de l’autre ſens, en-<lb/>ſorte que chaque étage d’un Pavillon ſe trouve diviſé en quatre <lb/>apartemens, qui doivent être compoſés d’une chambre pour deux <lb/>Officiers, de 18 pieds de long ſur 16 de large, & </s> <s xml:id="echoid-s8328" xml:space="preserve">d’une cuiſine ou <lb/>garde-robe pour les valets, de 16 pieds de long ſur 14 de large; <lb/></s> <s xml:id="echoid-s8329" xml:space="preserve">& </s> <s xml:id="echoid-s8330" xml:space="preserve">l’on fera enſorte de placer des Latrines au bout de chaque cor-<lb/>ridor, contre le mur des Cazernes.</s> <s xml:id="echoid-s8331" xml:space="preserve"/> </p> <div xml:id="echoid-div371" type="float" level="3" n="2"> <note position="right" xlink:label="note-0397-01" xlink:href="note-0397-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>29.</note> </div> <p> <s xml:id="echoid-s8332" xml:space="preserve">Chaque apartement pourra être occupé par un Officier en tems <lb/>de paix, & </s> <s xml:id="echoid-s8333" xml:space="preserve">par deux ou davantage en tems de guerre, quand la <lb/>Garniſon eſt renforcée, deſorte que douze Officiers peuvent loger <lb/>dans un Pavillon en tems de paix, & </s> <s xml:id="echoid-s8334" xml:space="preserve">24 en tems de guerre; </s> <s xml:id="echoid-s8335" xml:space="preserve">mais <lb/>pour fixer la quantité des logemens neceſſaires pour la Garniſon, <lb/>dans le tems où elle ſera la plus forte, on pourra ſuivre à peu près <lb/>la maxime de Mr. </s> <s xml:id="echoid-s8336" xml:space="preserve">de Vauban, qui eſt de ſupoſer 500 hommes de <lb/>pied par Baſtion, ou autres ouvrages de la Place équivalens, & </s> <s xml:id="echoid-s8337" xml:space="preserve">200 <lb/>chevaux, ce qui fait dix compagnies d’Infanterie, & </s> <s xml:id="echoid-s8338" xml:space="preserve">quatre de <lb/>Cavalerie, chaque compagnie d’Infanterie ayant trois Officiers, <lb/>& </s> <s xml:id="echoid-s8339" xml:space="preserve">celles de Cavalerie deux, on jugera par-là du nombre des Pavil-<lb/>lons qu’il faudra pour leur logement, auſſi-bien que de celui des <lb/>quartiers de Cazernes pour les Soldats.</s> <s xml:id="echoid-s8340" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8341" xml:space="preserve">Les Cazernes, qu’on voit repreſentées ſur la Planche 30, ont été <lb/> <anchor type="note" xlink:label="note-0397-02a" xlink:href="note-0397-02"/> faites à Bethune en 1728. </s> <s xml:id="echoid-s8342" xml:space="preserve">& </s> <s xml:id="echoid-s8343" xml:space="preserve">ſont des plus belles que je connoiſſe: <lb/></s> <s xml:id="echoid-s8344" xml:space="preserve">comme elles ſont deſtinées pour la Cavalerie, on voit que le plan <lb/>du rez-de-Chauſſée comprend des écuries d’une fort belle gran-<lb/>deur, & </s> <s xml:id="echoid-s8345" xml:space="preserve">bien éclairées chacune par deux croiſées; </s> <s xml:id="echoid-s8346" xml:space="preserve">ces écuries ſont <lb/>voûtées par des Voûtes ſurbaiſſées, au-deſſus deſquelles il y trois <lb/>étages doubles pour les Cavaliers: </s> <s xml:id="echoid-s8347" xml:space="preserve">attenant du même corps de Ca-<lb/>zernes, eſt un Pavillon pour les Officiers, dont la diſtribution eſt <lb/>ſuffiſamment détaillée par les plans profils & </s> <s xml:id="echoid-s8348" xml:space="preserve">élevations, pour en <lb/>avoir une parfaite intelligence, ſans qu’il ſoit beſoin que je m’y ar-<lb/>rête davantage: </s> <s xml:id="echoid-s8349" xml:space="preserve">d’ailleurs, comme j’en raporte le devis dans le ſi-<lb/>xiéme Livre, tel qu’il m’a été donné par Mr. </s> <s xml:id="echoid-s8350" xml:space="preserve">Dartezé, qui en a eu <lb/>la conduite, étant alors Ingenieur en chef de cette Place, on pour-<lb/>ra ſi l’on veut y avoir recours.</s> <s xml:id="echoid-s8351" xml:space="preserve"/> </p> <div xml:id="echoid-div372" type="float" level="3" n="3"> <note position="right" xlink:label="note-0397-02" xlink:href="note-0397-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>30.</note> </div> <pb o="76" file="0398" n="428" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s8352" xml:space="preserve">Un édifice encore fort neceſſaire dans une Ville de Guerre eſt <lb/> <anchor type="note" xlink:label="note-0398-01a" xlink:href="note-0398-01"/> un Hôpital pour les malades de la Garniſon, particulierement pour <lb/>les bleſſés en tems de ſiége: </s> <s xml:id="echoid-s8353" xml:space="preserve">ſa grandeur doit être reglée ſur la quan-<lb/>tité de malades que l’on aura dans la plus forte Garniſon, & </s> <s xml:id="echoid-s8354" xml:space="preserve">com-<lb/>me nous ſupoſons une Ville neuve, on pourra en eſtimer le nom-<lb/>bre ſur ceux des Villes voiſines, ce qui ſe fera encore ſur l’expe-<lb/>rience, qui montre que de 25 hommes ou environ, il y en a un de <lb/>malade: </s> <s xml:id="echoid-s8355" xml:space="preserve">cependant, il faut faire attention que dans les lieux aqua-<lb/>tiques, les maladies ſont plus generales que dans les endroits où <lb/>l’air eſt pur, & </s> <s xml:id="echoid-s8356" xml:space="preserve">ſur-tout quand on fait des remuemens de terres <lb/>conſiderables.</s> <s xml:id="echoid-s8357" xml:space="preserve"/> </p> <div xml:id="echoid-div373" type="float" level="3" n="4"> <note position="left" xlink:label="note-0398-01" xlink:href="note-0398-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>31.</note> </div> <p> <s xml:id="echoid-s8358" xml:space="preserve">Prévenu de ceci, on ſaura à pcu près le nombre de lits dont on <lb/>pourra avoir beſoin, & </s> <s xml:id="echoid-s8359" xml:space="preserve">par conſequent la grandeur des bâtimens <lb/>qu’il faudra faire, qui conſiſtent dans les ſales des malades, infir-<lb/>meries, cuiſines, pharmacie, celliers, blancheries, hangards pour <lb/>mettre le bois, enfin tous les logemens neceſſaires pour les Offi-<lb/>ciers de l’Hôpital: </s> <s xml:id="echoid-s8360" xml:space="preserve">les ſalles des malades doivent être au rez-de-<lb/>Chauſſée & </s> <s xml:id="echoid-s8361" xml:space="preserve">au premier étage; </s> <s xml:id="echoid-s8362" xml:space="preserve">on fera leur largeur de 42 pieds pour <lb/>mettre deux rangs de lits de 6 pieds de chaque côté, & </s> <s xml:id="echoid-s8363" xml:space="preserve">deux autres <lb/>dans le milieu, avec deux allées de 9 pieds de large chacune: </s> <s xml:id="echoid-s8364" xml:space="preserve">quant <lb/>à la longueur des ſalles, on doit la regler par le nombre de lits, <lb/>en comptant 4 pieds de largeur pour chacun, & </s> <s xml:id="echoid-s8365" xml:space="preserve">autant pour la diſ-<lb/>tance de l’un à l’autre: </s> <s xml:id="echoid-s8366" xml:space="preserve">au bout de la ſalle du rez-de-Chaſſuée, on <lb/>fait une Chapelle, qui doit être découverte de la ſalle d’enhaut, par <lb/>une tribune.</s> <s xml:id="echoid-s8367" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8368" xml:space="preserve">Quand il paſſe une riviere dans la Ville, il faut, autant qu’il eſt <lb/>poſſible, faire enſorte de conſtruire l’Hôpital dans ſon voiſinage, <lb/>ou au moins faire paſſer un ruiſſeau près de la cour ou du jardin, <lb/>afin d’avoir l’eau en abondance; </s> <s xml:id="echoid-s8369" xml:space="preserve">mais, ſans m’arrêter à tout ce qui <lb/>peut convenir à un Hôpital, on n’a qu’à voir celui que je raporte <lb/>ſur la Planche 31<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8370" xml:space="preserve">Si on ſe trouvoit dans le cas d’en faire conſtrui-<lb/> <anchor type="note" xlink:label="note-0398-02a" xlink:href="note-0398-02"/> re un, on ne feroit pas mal d’en communiquer le projet au Chi-<lb/>rurgien Major de la Place, afin que, de concert avec lui, on ne <lb/>neglige rien d’eſſentiel.</s> <s xml:id="echoid-s8371" xml:space="preserve"/> </p> <div xml:id="echoid-div374" type="float" level="3" n="5"> <note position="left" xlink:label="note-0398-02" xlink:href="note-0398-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>31.</note> </div> <p> <s xml:id="echoid-s8372" xml:space="preserve">Pour remplir le titre de ce Chapitre, il nous reſte à parler de la <lb/>Priſon: </s> <s xml:id="echoid-s8373" xml:space="preserve">on ſait bien qu’il eſt aſſez rare d’en conſtruire de neuves, <lb/>à moins que ce ne ſoit dans des places nouvellement bâties, par-<lb/>ce que dans les anciennes, il s’en trouve ordinairement dans les <lb/>Reduits, Châteaux, ou Tours; </s> <s xml:id="echoid-s8374" xml:space="preserve">mais, ſi l’on étoit dans le cas d’en <lb/>faire une, il faudroit qu’elle fût compoſée d’une cour entourée de <lb/>bâtimens, enſorte que le logement du Geolier ſoit ſur le devant, <pb file="0399" n="429"/> <pb file="0399a" n="430"/> <anchor type="figure" xlink:label="fig-0399a-01a" xlink:href="fig-0399a-01"/> <pb file="0400" n="431"/> <pb o="77" file="0401" n="432" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> & </s> <s xml:id="echoid-s8375" xml:space="preserve">n’ait aucune communication avec les priſonniers: </s> <s xml:id="echoid-s8376" xml:space="preserve">à droit de la <lb/>cour on pourra faire les cachots au rez-de-Chauſſée, & </s> <s xml:id="echoid-s8377" xml:space="preserve">au-deſſus <lb/>les priſons qui ſeroient deſtinées à de ſimples châtimens, pour le <lb/>Soldat & </s> <s xml:id="echoid-s8378" xml:space="preserve">le commun du peuple, enſorte qu’elles ne tiren<unsure/>t leur <lb/>jour que du côté de la cour, ne devant point avoir de fenêtres <lb/>ſur la ruë: </s> <s xml:id="echoid-s8379" xml:space="preserve">à gauche on pourra faire deux ou trois petites chambres, <lb/>pour loger les perſonnes qui meriteroient quelque conſideration; <lb/></s> <s xml:id="echoid-s8380" xml:space="preserve">& </s> <s xml:id="echoid-s8381" xml:space="preserve">le fond ſera occupé par d’autres priſons plus détachées du reſte <lb/>du bâtiment, pour reſſerrer les priſonniers qu’on voudroit empê-<lb/>cher d’avoir communication avec les gens du dehors, qui vont <lb/>& </s> <s xml:id="echoid-s8382" xml:space="preserve">viennent: </s> <s xml:id="echoid-s8383" xml:space="preserve">au-deſſus de ce batiment, on pourra faire la Chapelle, <lb/>afin que tous les priſonniers ſoient plus à portée d’entendre la Meſſe. </s> <s xml:id="echoid-s8384" xml:space="preserve"><lb/>J’ajoûterai, que quand il eſt queſtion d’un édifice comme celui-ci, <lb/>il faut faire les murs fort épais, & </s> <s xml:id="echoid-s8385" xml:space="preserve">toutes ces fenêtres bien grillées, <lb/>de même que les tuyaux des cheminées.</s> <s xml:id="echoid-s8386" xml:space="preserve"/> </p> <div xml:id="echoid-div375" type="float" level="3" n="6"> <figure xlink:label="fig-0399a-01" xlink:href="fig-0399a-01a"> <image file="0399a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0399a-01"/> </figure> </div> <p> <s xml:id="echoid-s8387" xml:space="preserve">Pour dire auſſi un mot des maiſons de Bourgeois, qui ſont re-<lb/>preſentées ſur la Planche 29<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8388" xml:space="preserve">il eſt bon qu’on ſache que le plan <lb/> <anchor type="note" xlink:label="note-0401-01a" xlink:href="note-0401-01"/> des cinq maiſons qu’on y voit exprime la moitié d’un des cantons <lb/>de la Planche 25, dont il a été fait mention dans le Chapitre hui-<lb/>tiéme; </s> <s xml:id="echoid-s8389" xml:space="preserve">ainſi par cette moitié on jugera aiſément du reſte: </s> <s xml:id="echoid-s8390" xml:space="preserve">à l’égard <lb/>de la décoration des façades, comme elles accompagnent le plan <lb/>dont je viens de parler, il ne faut qu’un coup d’œil pour en juger, <lb/>ſans qu’il ſoit beſoin d’un plus grand éclairciſſement; </s> <s xml:id="echoid-s8391" xml:space="preserve">je raporterai <lb/>ſeulement ici le Reglement qui a été fait au ſujet des maiſons qui ont <lb/>été bâties au Neuf-Briſack; </s> <s xml:id="echoid-s8392" xml:space="preserve">il preſcrit ce qu’il faut obſerver pour <lb/>empêcher les conteſtations entre les voiſins, & </s> <s xml:id="echoid-s8393" xml:space="preserve">à quoi chaque par-<lb/>ticulier doit s’aſſujettir en bâtiſſant dans une Place de Guerre.</s> <s xml:id="echoid-s8394" xml:space="preserve"/> </p> <div xml:id="echoid-div376" type="float" level="3" n="7"> <note position="right" xlink:label="note-0401-01" xlink:href="note-0401-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>29. & 25.</note> </div> </div> <div xml:id="echoid-div378" type="section" level="2" n="123"> <head xml:id="echoid-head275" xml:space="preserve">DEPAR LEROY.</head> <head xml:id="echoid-head276" style="it" xml:space="preserve">Reglement concernant les Maiſons qui ſe bâtiſſent au Neuf-<lb/>Briſack, ſur les Places que Sa Majeſté a bien voulu <lb/>accorder aux Particuliers.</head> <head xml:id="echoid-head277" xml:space="preserve"><emph style="sc">Premierement</emph>.</head> <p> <s xml:id="echoid-s8395" xml:space="preserve"><emph style="sc">TOus</emph> ceux qui bâtiſſent doivent ſe conformer pour les faces <lb/>deleurs bâtimens à celles qui ſont déja conſtruites ſur la gran-<lb/>de Place, tant pour la décoration de ces faces & </s> <s xml:id="echoid-s8396" xml:space="preserve">hauteur des cor- <pb o="78" file="0402" n="433" rhead="LA SCIENCE DES INGENIEURS,"/> niches, que pour la grandeur des Boutiques, Portes, & </s> <s xml:id="echoid-s8397" xml:space="preserve">Croiſées <lb/>qui doivent toutes être ſemblables, ainſi que la hauteur des combles.</s> <s xml:id="echoid-s8398" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div379" type="section" level="2" n="124"> <head xml:id="echoid-head278" xml:space="preserve">II.</head> <p> <s xml:id="echoid-s8399" xml:space="preserve"><emph style="sc">Chaque</emph> Particulier ſera obligé de faire un pignon de Maçon-<lb/>nerie ayant 2 pieds d’épaiſſeur dans ſes fondemens juſqu’au rez-de-<lb/>Chauſſée, 18 pouces du rez-de-Chauſſée juſqu’au plancher du Gre-<lb/>nier, & </s> <s xml:id="echoid-s8400" xml:space="preserve">16 pouces de-là au faîte du comble, & </s> <s xml:id="echoid-s8401" xml:space="preserve">ceux qui en ont bâtis <lb/>de Charpente ſeront tenus de les démonter, pour les faire ſolide-<lb/>ment; </s> <s xml:id="echoid-s8402" xml:space="preserve">& </s> <s xml:id="echoid-s8403" xml:space="preserve">comme il peut arriver quelque difficulté à l’occaſion de la <lb/>conſtruction de ces pignons, les Particuliers ne bâtiſſant pas tout à <lb/>la fois, celui qui commencera le premier ſera indemniſé par ſon <lb/>voiſin de la moitié de la depenſe à meſure que le pignon s’élevera, <lb/>ſans qu’il ſoit obligé d’attendre que ſon voiſin bâtiſſe ſur le devant.</s> <s xml:id="echoid-s8404" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div380" type="section" level="2" n="125"> <head xml:id="echoid-head279" xml:space="preserve">III.</head> <p> <s xml:id="echoid-s8405" xml:space="preserve"><emph style="sc">Ils</emph> obſerveront de mettre les auvens de même hauteur, obſer-<lb/>vant la même choſe aux enſeignes qui ſeront de pareille grandeur <lb/>le plus que faire ſe pourra.</s> <s xml:id="echoid-s8406" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div381" type="section" level="2" n="126"> <head xml:id="echoid-head280" xml:space="preserve">IV.</head> <p> <s xml:id="echoid-s8407" xml:space="preserve"><emph style="sc">Dans</emph> la conſtruction des Caves, il eſt ordonné d’en voûter <lb/>au moins une dans chaque maiſon.</s> <s xml:id="echoid-s8408" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div382" type="section" level="2" n="127"> <head xml:id="echoid-head281" xml:space="preserve">V.</head> <p> <s xml:id="echoid-s8409" xml:space="preserve"><emph style="sc">Les</emph> combles dans un même quarré ſeront de même hauteur <lb/>afin de ſe raccorder parfaitement avec le deſſein.</s> <s xml:id="echoid-s8410" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div383" type="section" level="2" n="128"> <head xml:id="echoid-head282" xml:space="preserve">VI.</head> <p> <s xml:id="echoid-s8411" xml:space="preserve"><emph style="sc">Ils</emph> éloigneront le plus qu’ils pourront les lieux communs, ou <lb/>latrines, des puits; </s> <s xml:id="echoid-s8412" xml:space="preserve">non-ſeulement des leurs, mais auſſi de ceux que <lb/>leurs voiſins feront conſtruire chez eux.</s> <s xml:id="echoid-s8413" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div384" type="section" level="2" n="129"> <head xml:id="echoid-head283" xml:space="preserve">VII.</head> <p> <s xml:id="echoid-s8414" xml:space="preserve"><emph style="sc">Et</emph> comme les tranſpirations de ces latrines pourroient à la fin <lb/>gâter & </s> <s xml:id="echoid-s8415" xml:space="preserve">corrompre les eaux des Puits, il eſt très-expreſſement en-<lb/>joint à tous les Particuliers de faire citerner la foſſe de leurs latri-<lb/>nes avec de bonne Maçonnerie, & </s> <s xml:id="echoid-s8416" xml:space="preserve">un enduit de ciment, obſer- <pb o="79" file="0403" n="434" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> vant de laiſſer un trou à la Voûte pour les vuider quand il ſera tems.</s> <s xml:id="echoid-s8417" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div385" type="section" level="2" n="130"> <head xml:id="echoid-head284" xml:space="preserve">VIII.</head> <p> <s xml:id="echoid-s8418" xml:space="preserve"><emph style="sc">Il</emph> eſt encore enjoint à tous ceux qui ont obtenu des Places de <lb/>les bâtir inceſſamment, afin qu’elles ſoient achevées dans le terme <lb/>qu’on leur a donné, ſous peine de perdre leſdites Places, que l’on <lb/>donnera à d’autres, & </s> <s xml:id="echoid-s8419" xml:space="preserve">même les legers Bâtimens qui ſont deſſus, <lb/>lorſque le tems de leur ſoûmiſſion ſera expiré.</s> <s xml:id="echoid-s8420" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div386" type="section" level="2" n="131"> <head xml:id="echoid-head285" xml:space="preserve">IX.</head> <p> <s xml:id="echoid-s8421" xml:space="preserve"><emph style="sc">Il</emph> eſt très-expreſſement ordonné à tous Maçons & </s> <s xml:id="echoid-s8422" xml:space="preserve">Charpentiers <lb/>de ſe conformer à ce Reglement, ſous peine de priſon, & </s> <s xml:id="echoid-s8423" xml:space="preserve">d’en ré-<lb/>pondre e<unsure/>n leur propre & </s> <s xml:id="echoid-s8424" xml:space="preserve">privé nom.</s> <s xml:id="echoid-s8425" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s8426" xml:space="preserve">Et afin que perſonne n’en ignore, ſera le preſent Reglement lû & </s> <s xml:id="echoid-s8427" xml:space="preserve"><lb/>publié à ſon de Tambour & </s> <s xml:id="echoid-s8428" xml:space="preserve">affiché par-tout où beſoin ſera.</s> <s xml:id="echoid-s8429" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div387" type="section" level="2" n="132"> <head xml:id="echoid-head286" xml:space="preserve">CHAPITRE ONZIEME.</head> <head xml:id="echoid-head287" style="it" xml:space="preserve">De la Cantine, de la Glaciere, de la Boulangerie, & des <lb/>Moulins.</head> <p> <s xml:id="echoid-s8430" xml:space="preserve">DANS toutes les Villes de Guerre où la Maltote eſt établie, <lb/>le Roy veut bien accorder à la Garniſon une Cantine; </s> <s xml:id="echoid-s8431" xml:space="preserve">c’eſt-<lb/>à-dire un lieu où elle ait le privilege d’avoir de l’Eau-de-Vie, du <lb/>Vin, de la Bierre, à un’certain prix beaucoup au-deſſous de celui <lb/>des Cabarets. </s> <s xml:id="echoid-s8432" xml:space="preserve">Quand cette Cantine ſetrouve dans une grande Ville, <lb/>c’eſt à celui qui en eſt l’Entrepreneur de ſe pourvoir d’une Maiſon <lb/>qui lui convienne: </s> <s xml:id="echoid-s8433" xml:space="preserve">mais, dans une Citadelle ou autre Fortereſſe qui <lb/>n’eſt habitée que par des Gens de Guerre, la Cantine eſt preſque le <lb/>ſeul endroit d’où la Garniſon peut tirer des raffraichiſſemens; </s> <s xml:id="echoid-s8434" xml:space="preserve">& </s> <s xml:id="echoid-s8435" xml:space="preserve"><lb/>alors ce ſont les Ingenieurs qui ſont chargés de la conſtruction & </s> <s xml:id="echoid-s8436" xml:space="preserve"><lb/>des réparations de cet Edifice, ce qui m’engage d’en faire mention.</s> <s xml:id="echoid-s8437" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8438" xml:space="preserve">Une Cantine doit être compoſée de pluſieurs Caves & </s> <s xml:id="echoid-s8439" xml:space="preserve">au rez-de-<lb/>Chauſſée d’une Cuiſine, d’un Garde-manger, de trois ou quatre <lb/>Chambres pour donner à boire aux Soldats, d’une Salle pour l’Au-<lb/>berge des Officiers, d’une Ecurie pour 12 ou 15 Chevaux, & </s> <s xml:id="echoid-s8440" xml:space="preserve">d’un <pb o="80" file="0404" n="435" rhead="LA SCIENCE DES INGENIEURS,"/> couvert pour mettre le bois: </s> <s xml:id="echoid-s8441" xml:space="preserve">au-deſſus du corps de logis, on diſtri-<lb/>buera auſſi un nombre de Chambres qui répondront ſi l’on veut à <lb/>celle du rez-de-Chauſſée; </s> <s xml:id="echoid-s8442" xml:space="preserve">elles ſerviront pour loger les Etrangers. <lb/></s> <s xml:id="echoid-s8443" xml:space="preserve">La Cantine qui eſt raportée ſur la Planche 32. </s> <s xml:id="echoid-s8444" xml:space="preserve">eſt à peu-près dans <lb/> <anchor type="note" xlink:label="note-0404-01a" xlink:href="note-0404-01"/> ce goût-là.</s> <s xml:id="echoid-s8445" xml:space="preserve"/> </p> <div xml:id="echoid-div387" type="float" level="3" n="1"> <note position="left" xlink:label="note-0404-01" xlink:href="note-0404-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>32.</note> </div> <p> <s xml:id="echoid-s8446" xml:space="preserve">Pour procurer aux Officiers d’une Garniſon le plaiſir de boire frais <lb/>en Eté, on fait aſſés ſouvent une Glaciére dont la conſtruction & </s> <s xml:id="echoid-s8447" xml:space="preserve"><lb/>l’entretien regardent auſſi les Fortifications; </s> <s xml:id="echoid-s8448" xml:space="preserve">mais c’eſt l’Etat Major <lb/>de la Place qui prend le ſoin de la faire remplir. </s> <s xml:id="echoid-s8449" xml:space="preserve">Pour la bien placer, <lb/>il faut choiſir un lieu élevé, comme par exemple un Baſtion plain, <lb/>on fait une foſſe en forme d’entonnoir, on lui donne environ 20 <lb/>pieds de diamêtre & </s> <s xml:id="echoid-s8450" xml:space="preserve">10 ou 12 de profondeur plus ou moins: </s> <s xml:id="echoid-s8451" xml:space="preserve">ſi <lb/>l’on rencontroit pour faire cette foſſe une terre glaiſe, qui n’eût point <lb/>été remuée, on pourroit ſe diſpenſer de la revêtir de Maçonnerie; <lb/></s> <s xml:id="echoid-s8452" xml:space="preserve">mais quand cela ne ſe trouve point, on y fait un revêtement de <lb/>Briques de deux pieds d’épaiſſeur ou davantage ſelon qu’on aura <lb/>lieu de craindre la pouſſée des terres qui n’a guére lieu dans cette <lb/>occaſion, parce que donnant pour profondeur à peu-près le rayon <lb/>du grand cercle, les terres ſe trouvent avoir leur pente naturelle, <lb/>& </s> <s xml:id="echoid-s8453" xml:space="preserve">par conſéquent ſe ſoûtiendront ſous l’angle de 45 dégrés. </s> <s xml:id="echoid-s8454" xml:space="preserve">Au fond <lb/>de la Glaciére l’on fait un petit Puits de 3 pieds de diamétre ſur 5 <lb/>ou 6 de profondeur qui doit être auſſi revêtu; </s> <s xml:id="echoid-s8455" xml:space="preserve">il ſert à recevoir <lb/>l’eau de la glace, qui ne manqueroit pas de fondre celle du fond, ſi <lb/>elle n’avoit un écoulement: </s> <s xml:id="echoid-s8456" xml:space="preserve">ainſi l’on ſent bien que c’eſt par le <lb/>Puits qu’il faut commencer la Maçonnerie; </s> <s xml:id="echoid-s8457" xml:space="preserve">& </s> <s xml:id="echoid-s8458" xml:space="preserve">quand on ſera par-<lb/>venu au bord, il faudra faire un roüet compoſé de bon bois de <lb/>chêne, pour ſervir d’empatement aux premieres aſſiſes du revêtement <lb/>de l’entonnoir: </s> <s xml:id="echoid-s8459" xml:space="preserve">quand on l’a rempli de glace, on ferme le Puits par <lb/>un plancher à claire voye; </s> <s xml:id="echoid-s8460" xml:space="preserve">la Maçonnerie étant achevée, & </s> <s xml:id="echoid-s8461" xml:space="preserve">lui ayant <lb/>donné tout le tems de ſecher, on fait pour couvrir la Glaciere une <lb/>charpente en figure de cône, dont la baſe repoſe ſur le bord de la <lb/>Maçonnerie, & </s> <s xml:id="echoid-s8462" xml:space="preserve">cette charpente eſt garni de chaume depuis la <lb/>pointe du cône juſqu’à terre, d’une épaiſſeur ſuffiſante pour empê-<lb/>cher le Soleil de pénétrer à travers; </s> <s xml:id="echoid-s8463" xml:space="preserve">c’eſt pourquoi, afin de tenir cet <lb/>endroit plus à l’ombre, on plante à l’entour des arbres aſſés près les <lb/>uns des autres pour qu’ils forment par la ſuite un berceau: </s> <s xml:id="echoid-s8464" xml:space="preserve">pour <lb/>entrer dans la Glaciére, on fait une petite allée de 10 à 12 pieds <lb/>de longueur & </s> <s xml:id="echoid-s8465" xml:space="preserve">4 de largeur, voûtée & </s> <s xml:id="echoid-s8466" xml:space="preserve">tournée du côté du Nord, <lb/>on la ferme par deux portes, dont il y en a une à chaque extrê-<lb/>mité. </s> <s xml:id="echoid-s8467" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0404-02a" xlink:href="note-0404-02"/> 32.</s> </p> <pb file="0405" n="436"/> <pb file="0405a" n="437"/> <p> <s xml:id="echoid-s8468" xml:space="preserve"> <anchor type="figure" xlink:label="fig-0405a-01a" xlink:href="fig-0405a-01"/> </s> </p> <pb file="0406" n="438"/> <pb o="81" file="0407" n="439" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s8469" xml:space="preserve"> <anchor type="note" xlink:label="note-0407-01a" xlink:href="note-0407-01"/> </s> <s xml:id="echoid-s8470" xml:space="preserve">deſſinés trop en petit pour être apperçûs diſtinctement.</s></p> </div> <div xml:id="echoid-div389" type="float" level="2" n="3"> <figure xlink:label="fig-0405a-01" xlink:href="fig-0405a-01a"> <image file="0405a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0405a-01"/> </figure> <note position="right" xlink:label="note-0407-01" xlink:href="note-0407-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>34.</note> </div> <p> <s xml:id="echoid-s8471" xml:space="preserve">La conſtruction des Fours n’a rien de particulier que les moindres <lb/>Maçons ne ſachent; </s> <s xml:id="echoid-s8472" xml:space="preserve">je dirai ſeulement, que les Voûtes doivent être <lb/>faites avec des briques d’une bonne terre bien préparée & </s> <s xml:id="echoid-s8473" xml:space="preserve">bien cuite, <lb/>poſées de bout comme des vouſſoirs avec du mortier fin: </s> <s xml:id="echoid-s8474" xml:space="preserve">à l’égard <lb/>du carrelage dont l’étenduë du Four doit être couverte, il faut pour <lb/>poſer les carreaux ſe ſervir de mortier de terre glaiſe, & </s> <s xml:id="echoid-s8475" xml:space="preserve">non de ce-<lb/>lui fait de Chaux & </s> <s xml:id="echoid-s8476" xml:space="preserve">de Sable, parce que la chaleur le feroit enfler, <lb/>& </s> <s xml:id="echoid-s8477" xml:space="preserve">détacheroit les carreaux en peu de tems.</s> <s xml:id="echoid-s8478" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8479" xml:space="preserve">L’Edifice doit être compoſé de deux Cours, la premiere pour la <lb/>commodité des mitrons, la ſeconde pour les Charrois & </s> <s xml:id="echoid-s8480" xml:space="preserve">les Ecuries: <lb/></s> <s xml:id="echoid-s8481" xml:space="preserve">dans le bâtiment il doit y avoir 2 Magaſins pour renfermer le pain, <lb/>2 Bureaux pour le diſtribuer; </s> <s xml:id="echoid-s8482" xml:space="preserve">au-deſſus l’on fera des logemens pour <lb/>les Commis des Vivres, & </s> <s xml:id="echoid-s8483" xml:space="preserve">les Farines pourront être miſes dans les <lb/>Greniers au-deſſus des hangards: </s> <s xml:id="echoid-s8484" xml:space="preserve">mais, pour donner une idée plus <lb/>ſenſible de tout ceci, on peut voir la Boulangerie répreſentée ſur <lb/>la Planche 32. </s> <s xml:id="echoid-s8485" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0407-02a" xlink:href="note-0407-02"/> 32.</s> </p> <p><s xml:id="echoid-s8486" xml:space="preserve">mer les Farines comme on le peut voir ſur la même Planche. lant des Machines.</s></p> <pb o="82" file="0408" n="440" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div391" type="section" level="1" n="86"> <head xml:id="echoid-head288" xml:space="preserve">CHAPITRE DOUZIE’ME.</head> <head xml:id="echoid-head289" style="it" xml:space="preserve">De la Conſtruction des Puits & Citernes.</head> <p><s xml:id="echoid-s8487" xml:space="preserve">tout ce qui eſt neceſſaire pour en tirer l’eau.</s></p> <p><s xml:id="echoid-s8488" xml:space="preserve">rencontre, voici comme ces ſortes de Puits ſe font.</s></p> <pb file="0409" n="441"/> <pb file="0409a" n="442"/> <p><s xml:id="echoid-s8489" xml:space="preserve"><anchor type="figure" xlink:label="fig-0409a-01a" xlink:href="fig-0409a-01"/></s></p> <pb file="0410" n="443"/> <pb o="83" file="0411" n="444" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p><s xml:id="echoid-s8490" xml:space="preserve">de plomb pour la conduire dans le baſſin.</s></p> <div xml:id="echoid-div391" type="float" level="2" n="1"> <figure xlink:label="fig-0409a-01" xlink:href="fig-0409a-01a"> <image file="0409a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0409a-01"/> </figure> </div> <p><s xml:id="echoid-s8491" xml:space="preserve">ſur le champ, ou au bout de quelque tems, de monter. ſieurs fontaines qui font un fort bel effet. <pb o="84" file="0412" n="445" rhead="LA SCIENCE DES INGENIEURS,"/> juſqu’au ſommet des maiſons. l’eau monte avec impetuoſité, & rempliſſe le puits. à groſſir. de Mathematique.</s></p> <pb o="85" file="0413" n="446" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p><s xml:id="echoid-s8492" xml:space="preserve"> <anchor type="note" xlink:label="note-0413-01a" xlink:href="note-0413-01"/> nes demande beaucoup d’aplication pour les faire bonnes, nous allons détailler tout ce qui peut apartenir à ce ſujet; &, pour ne rien dire qui n’ait été déja executé avec ſuccés, je prendrai pour exemple la citerne qui a été faite en 1722 à Charlemont par Mr. de Breval; elle eſt au moins auſſi belle que celle de Dunkerque, dont on fait tant de cas. Cette citerne a, comme on le peut voir par le plan, 15 toiſes de longueur, ſur 6 toiſes 4 pieds de largeur, y compris les deux murs de refends qu’on a fait pour porter les Voûtes, parce que pour ces ſortes d’ouvrages, qui doivent être à l’épreuve de la Bombe, crainte des accidens qui peuvent arriver en tems de ſiége, il vaut mieux faire trois Voûtes chacune d’une grandeur médiocre, que de n’en faire qu’une ſeule qui ſeroit trop élevée & trop foible.</s></p> </div> <div xml:id="echoid-div393" type="float" level="1" n="1"> <note position="right" xlink:label="note-0413-01" xlink:href="note-0413-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>33.</note> </div> <div xml:id="echoid-div394" type="section" level="1" n="87"> <p> <s xml:id="echoid-s8493" xml:space="preserve">Le plan fait voir auſſi, qu’on a pratiqué une porte dans le milieu <lb/>de chaque mur de refend, pour la communication de l’eau, & </s> <s xml:id="echoid-s8494" xml:space="preserve">que <lb/>l’on a fait un citerneau de 9 pieds en quarré, pour que l’eau puiſſe <lb/>filtrer avant d’entrer dans la citerne; </s> <s xml:id="echoid-s8495" xml:space="preserve">c’eſt pourquoi le fond de ce <lb/>citerneau eſt 8 pieds plus haut que celui de la citerne.</s> <s xml:id="echoid-s8496" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8497" xml:space="preserve">Pour tirer l’eau, on a conſtruit au rez-de-Chauſſée de la Place <lb/>quatre niches quarrées de 7 pieds & </s> <s xml:id="echoid-s8498" xml:space="preserve">demi dans œuvre, dont deux <lb/>ſervent à loger les pompes, & </s> <s xml:id="echoid-s8499" xml:space="preserve">les deux autres pour recevoir l’eau; <lb/></s> <s xml:id="echoid-s8500" xml:space="preserve">&</s> <s xml:id="echoid-s8501" xml:space="preserve">, afin qu’on en puiſſe tirer juſqu’à la dernier goûte, les tuyaux <lb/>des pompes vont répondre dans un puiſart, qui eſt une eſpece de <lb/>rigole qui regne ſur toute la largeur, dans l’une de ces niches on <lb/>a pratiqué une porte pour deſcendre avec une échelle dans la ci-<lb/>terne, lorſque l’on veut y faire quelque reparation: </s> <s xml:id="echoid-s8502" xml:space="preserve">ces niches ont <lb/>été voutées à l’épreuve de la Bombe, & </s> <s xml:id="echoid-s8503" xml:space="preserve">ſont decorées extrerieure-<lb/>ment par une façade de pierre de taille à joints refendus, & </s> <s xml:id="echoid-s8504" xml:space="preserve">couron-<lb/>nées d’une corniche, elles ſont fermées par des portes de madriers, <lb/>auſſi bien que l’entrée de la citerne. </s> <s xml:id="echoid-s8505" xml:space="preserve">Je crois que cette explication <lb/>ſuffit, aidé des plans & </s> <s xml:id="echoid-s8506" xml:space="preserve">profils, pour en donner une connoiſſance <lb/>parfaite; </s> <s xml:id="echoid-s8507" xml:space="preserve">ainſi, je ne parlerai que de ce qu’on a obſervé en la conſ-<lb/>truiſant.</s> <s xml:id="echoid-s8508" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8509" xml:space="preserve">Après avoir deblayé les terres juſqu’à une profondeur conve-<lb/>nable, on a fait un maſſif de maçonnerie d’environ 3 pieds d’épaiſ-<lb/>ſeur, dirigé en pente de 6 pouces vers le puiſart des pompes, & </s> <s xml:id="echoid-s8510" xml:space="preserve"><lb/>ce maſſif occupant tout le fond de la citerne a ſervi en même tems <lb/>de fondement aux piés-droits des Voûtes & </s> <s xml:id="echoid-s8511" xml:space="preserve">aux murs de refends. <lb/></s> <s xml:id="echoid-s8512" xml:space="preserve">Après l’avoir bien arraſé, on l’a couvert d’un rang de briques poſées <pb o="86" file="0414" n="447" rhead="LA SCIENCE DES INGENIEURS,"/> de plat en mortier de ciment, ſur ce premier rang on en a fait un <lb/>ſecond, & </s> <s xml:id="echoid-s8513" xml:space="preserve">ſur celui-ci un troiſiéme, toûjours avec du mortier de <lb/>ciment & </s> <s xml:id="echoid-s8514" xml:space="preserve">plain ſur joints: </s> <s xml:id="echoid-s8515" xml:space="preserve">le fond du citerneau a été auſſi conſtruit <lb/>de la même maniere.</s> <s xml:id="echoid-s8516" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8517" xml:space="preserve">La ſuperficie du fond de la citerne étant achevée, l’on a élevé <lb/>les murs du refends & </s> <s xml:id="echoid-s8518" xml:space="preserve">les piés-droits des Voûtes, auſquels l’on <lb/>a donné 3 pieds d’épaiſſeur: </s> <s xml:id="echoid-s8519" xml:space="preserve">les murs du pourtour, tant de la citer-<lb/>ne que du citerneau, ont été parementés de briques, poſées en <lb/>mortier de ciment, ſur l’épaiſſeur de deux briques, & </s> <s xml:id="echoid-s8520" xml:space="preserve">d’une & </s> <s xml:id="echoid-s8521" xml:space="preserve">de-<lb/>mi alternativement, & </s> <s xml:id="echoid-s8522" xml:space="preserve">le reſte de cette épaiſſeur de moilon; </s> <s xml:id="echoid-s8523" xml:space="preserve">enſui-<lb/>te l’on a poſé les ceintres ſur leſquels l’on a établi la premiere Voû-<lb/>te, d’une brique d’épaiſſeur faite en mortier de ciment; </s> <s xml:id="echoid-s8524" xml:space="preserve">ſur cette <lb/>Voûte l’on en a faite une ſeconde, & </s> <s xml:id="echoid-s8525" xml:space="preserve">ſur celle-ci une troiſiéme de <lb/>moilon plat, après quoi l’on a rempli de maçonnerie les reins de <lb/>la Voûte du berceau du milieu, juſqu’à la hauteur qu’on voit dé-<lb/>terminé par le profil, après avoir bien arraſé les pentes, on y a <lb/>apliqué une chape de ciment qui couvre les trois Voûtes, & </s> <s xml:id="echoid-s8526" xml:space="preserve">cette <lb/>chape a été faite à peu près de la même façon, qu’il eſt enſeigné <lb/>dans le Chapitre onziéme du troiſiéme Livre.</s> <s xml:id="echoid-s8527" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8528" xml:space="preserve">L’on a fait un enduit ſur le pavé de la citerne, & </s> <s xml:id="echoid-s8529" xml:space="preserve">ſur l’interieur <lb/>du mur du pourtour, de la même épaiſſeur qu’on fait ordinairement <lb/>les chapes de ciment, & </s> <s xml:id="echoid-s8530" xml:space="preserve">fabriqué avec les mêmes précautions, <lb/>excepté ſeulement qu’au lieu de pouſſiere de thuilaux, on s’eſt ſer-<lb/>vi de terraſſe de Hollande, comme étant beaucoup meilleure.</s> <s xml:id="echoid-s8531" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8532" xml:space="preserve">Quand on fait des citernes dans des lieux aquatiques, on enve-<lb/>lope exterieurement toute la maçonnerie, par un bon courroi de <lb/>terre glaiſe, bien petrie & </s> <s xml:id="echoid-s8533" xml:space="preserve">bien battuë, crainte que les eaux qui <lb/>proviendroient des ſources, ou de quelqu’autre cauſe, ne l’endom-<lb/>magent, ou ne ſe mêlent avec celle de la citerne, ſi à la longue <lb/>elles parvenoient à s’y faire une entrée; </s> <s xml:id="echoid-s8534" xml:space="preserve">car l’on entend bien que <lb/>ces eaux ne pourroient être que de mauvaiſe qualité, puiſque, ſi <lb/>elles étoient bonnes, on ne ſeroit point dans la neceſſité de faire <lb/>une citerne.</s> <s xml:id="echoid-s8535" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8536" xml:space="preserve">J’en raporterai encore ici une fort belle, qui s’eſt faite à Ca-<lb/>lais, à peu près dans le même tems que celle de Charlemont, <lb/>dont les developemens ſont ſuffiſamment détaillées ſur la 34<emph style="sub">e</emph>. </s> <s xml:id="echoid-s8537" xml:space="preserve">Plan-<lb/> <anchor type="note" xlink:label="note-0414-01a" xlink:href="note-0414-01"/> che, que je ne m’arrêterai point à expliquer, parce qu’on en trou-<lb/>vera le devis dans le ſixiéme Livre, qui en facilitera parfaitement <lb/>l’intelligence, & </s> <s xml:id="echoid-s8538" xml:space="preserve">que je donne d’ailleurs pour ſervir de modele, <lb/>quand on ſera dans le cas de projetter de pareils ouvrages.</s> <s xml:id="echoid-s8539" xml:space="preserve"/> </p> <div xml:id="echoid-div394" type="float" level="2" n="1"> <note position="left" xlink:label="note-0414-01" xlink:href="note-0414-01a" xml:space="preserve"><emph style="sc">Planch</emph>, <lb/>34.</note> </div> <p> <s xml:id="echoid-s8540" xml:space="preserve">La grandeur des citernes devant être reglée ſur la quantité d’eau <pb file="0415" n="448"/> <pb file="0415a" n="449"/> <anchor type="figure" xlink:label="fig-0415a-01a" xlink:href="fig-0415a-01"/> <pb file="0416" n="450"/> <pb o="87" file="0417" n="451" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> que les toits des bâtimens les plus à portée peuvent fournir, il faut, <lb/>afin de ſavoir combien on pourra en recueillir, faire des experiences <lb/>ſur les lieux, pour voir ce qu’il tombe de pouces d’eau chaque an-<lb/>née, c’eſt-à-dire, de combien de hauteur d’eau les pluyes couvri-<lb/>roient la ſurface de la terre, ſi elles s’y conſervoient ſans s’écouler, <lb/>s’imbiber, ni s’évaporer; </s> <s xml:id="echoid-s8541" xml:space="preserve">&</s> <s xml:id="echoid-s8542" xml:space="preserve">, ſupoſant qu’il en tombe 20 pouces, il <lb/>faut meſurer l’étenduë qu’occupent les bâtimens, dont on veut ra-<lb/>maſſer l’eau des toits, ſans s’embarraſſer de leur figure, ni de la gran-<lb/>deur de leur ſurface, puiſque l’eau qu’ils recevront ſera toûjours <lb/>équivalente à celle qui ſeroit tombée ſur le terrain qu’occupe le bâ-<lb/>timent, ſi l’eſpace avoit été decouvert comme en plaine campagne: <lb/></s> <s xml:id="echoid-s8543" xml:space="preserve">or, ſi cet eſpace ſe trouvoit par exemple de 1200 toiſes quarrées, <lb/>il faudroit multiplier cette quantité par 20 pouces, & </s> <s xml:id="echoid-s8544" xml:space="preserve">le produit <lb/>donnera 332 toiſes 4 pieds cubes, pour la quantité d’eau que la ci-<lb/>terne recevra dans le courant d’une année, ſurquoi il faut prendre <lb/>garde de la faire toûjours plus grande, afin que dans le tems des <lb/>plus grandes eaux, elle ne monte jamais juſqu’à la naiſſance de la <lb/>Voûte.</s> <s xml:id="echoid-s8545" xml:space="preserve"/> </p> <div xml:id="echoid-div395" type="float" level="2" n="2"> <figure xlink:label="fig-0415a-01" xlink:href="fig-0415a-01a"> <image file="0415a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0415a-01"/> </figure> </div> <p> <s xml:id="echoid-s8546" xml:space="preserve">Pour ſavoir la maniere dont on pourra faire ces experiences, je <lb/>raporterai ce qui ſe pratique à l’Obſervatoire Royal de Paris, que <lb/>j’accompagnerai de quelque exemple dont on pourra ſe ſervir dans <lb/>l’occaſion.</s> <s xml:id="echoid-s8547" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8548" xml:space="preserve">Pour connoître la quantité d’eau de pluye qui tombe à l’Obſer-<lb/>vatoire, on place, dans une Tour découverte, un vaiſſeau de fer <lb/>blanc de 4 pieds de ſuperficie, avec des rebors de 6 pouces de <lb/>hauteur, ce vaiſſeau eſt fait en pente vers l’un de ſes angles où il <lb/>y a un bout de tuyau pour conduire l’eau dans une cruche, on a <lb/>grand ſoin de meſurer exactement toute l’eau qui eſt amaſſée dans <lb/>cette cruche, avec un vaſe de figure cubique qui a ſon côté de <lb/>3 pouces, enſorte que 32 lignes de hauteur d’eau dans ce petit vaſe, <lb/>valent une demi ligne ſur la ſuperficie du grand vaiſſeau; </s> <s xml:id="echoid-s8549" xml:space="preserve">car il eſt <lb/>bon de remarquer qu’on ne remplit point entierement la meſure, <lb/>& </s> <s xml:id="echoid-s8550" xml:space="preserve">qu’on ſe contente d’y mettre de l’eau juſqu’à une ligne qui eſt <lb/>tracée en dedans à 4 lignes au-deſſous du bord. </s> <s xml:id="echoid-s8551" xml:space="preserve">Pour avoir les 32 <lb/>lignes d’eau dont on vient de faire mention, on écrit ſur un Re-<lb/>giſtre toutes les meſures qu’on a ramaſſees pendant le courant de <lb/>chaque mois, pour en faire une ſomme au bout de l’année, dont <lb/>on prend la moitié pour avoir en ligne la quantité d’eau qui eſt <lb/>tombée.</s> <s xml:id="echoid-s8552" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8553" xml:space="preserve">Mr. </s> <s xml:id="echoid-s8554" xml:space="preserve">de Vauban ayant envoyé à l’Academie Royale des Sciences <lb/>un Memoire de la quantité d’eau de pluye qui eſt tombée dans la <pb o="88" file="0418" n="452" rhead="LA SCIENCE DES INGENIEURS,"/> Citadelle de Lille pendant 10 années depuis 1685. </s> <s xml:id="echoid-s8555" xml:space="preserve">juſqu’à 1694. <lb/></s> <s xml:id="echoid-s8556" xml:space="preserve">Mr. </s> <s xml:id="echoid-s8557" xml:space="preserve">de la Hire a comparé les ſix dernieres années de l’Obſervation <lb/>de Lille, avec les mêmes années qu’il a obſervées très-exactement <lb/>à Paris, & </s> <s xml:id="echoid-s8558" xml:space="preserve">en voici le Paralelle.</s> <s xml:id="echoid-s8559" xml:space="preserve"/> </p> <note position="right" xml:space="preserve"><emph style="sc">Anne’es</emph>. # <emph style="sc">A</emph> <emph style="sc">Lille</emph>. # <emph style="sc">A</emph> <emph style="sc">Paris</emph>. <lb/># # pouces. # lignes. # pouces. # lignes. <lb/>1689 # 18 # 9 # 18 # 11 {1/2} <lb/>1690 # 24 # 8 {1/2} # 23 # 3 {1/2} <lb/>1691 # 15 # 2 # 14 # 5 {1/4} <lb/>1692 # 25 # 4 {1/2} # 22 # 7 {1/2} <lb/>1693 # 30 # 3 {1/2} # 22 # 8 <lb/>1694 # 19 # 3 # 19 # 9 <lb/>6 # Années. # 133 # 6 {1/2} # 121 # 9 <lb/></note> <p> <s xml:id="echoid-s8560" xml:space="preserve">Par la Comparaiſon de ces 6 Années, on voit en general qu’il <lb/>pleut un peu plus à Lille qu’à Paris, & </s> <s xml:id="echoid-s8561" xml:space="preserve">que la moyenne Année à <lb/>Lille donne 22 pouces 3 lignes, & </s> <s xml:id="echoid-s8562" xml:space="preserve">à Paris 20 pouces 3 lignes. </s> <s xml:id="echoid-s8563" xml:space="preserve">Ce-<lb/>pendant on n’en compte ordinairement que 19.</s> <s xml:id="echoid-s8564" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div397" type="section" level="1" n="88"> <head xml:id="echoid-head290" xml:space="preserve">CHAPITRE TREIZIE’ME.</head> <head xml:id="echoid-head291" style="it" xml:space="preserve">Où l’on donne les Régles générales que l’on doit obſerver dans <lb/>la Conſtruction des Bâtimens.</head> <p> <s xml:id="echoid-s8565" xml:space="preserve"><emph style="sc">APres</emph> avoir expliqué, dans les Chapitres précédens, les <lb/>propriétés & </s> <s xml:id="echoid-s8566" xml:space="preserve">la diſtribution des principaux Edifices Militaires, <lb/>il me reſte à faire le détail de beaucoup de choſes qui appartiennent <lb/>à leur conſtruction & </s> <s xml:id="echoid-s8567" xml:space="preserve">à celle des Bâtimens pour les Particuliers dont <lb/>je ne traiterai qu’en general, parce qu’ils ne font partie de mon Ou-<lb/>vrage, qu’autant qu’un Ingenieur, ſans vouloir être Architecte du <lb/>premier ordre, ne peut ignorer les proportions qu’il faut don-<lb/>ner aux parties d’un Bâtiment pour être commode & </s> <s xml:id="echoid-s8568" xml:space="preserve">gratieux. </s> <s xml:id="echoid-s8569" xml:space="preserve">Ce <lb/>ſont ces choſes, dis-je, qu’il faut ſavoir, parce qu’elles ſe rencontrent <lb/>ſouvent dans les Edifices Militaires, qui, quoique très-ſimples par <lb/>eux-mêmes, ont pourtant beſoin d’être dirigés ſelon certaines régles <lb/>deſquelles on ne peut s’écarter ſans tomber dans quelque défaut. <lb/></s> <s xml:id="echoid-s8570" xml:space="preserve">Quant aux détails que j’ai deſſein d’inſinuer, ils ſont de la derniere <pb o="89" file="0419" n="453" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> conſéquence, puiſque ce n’eſt que par eux qu’on peut dreſſer les <lb/>Devis qui doivent précéder la conſtruction des Bâtimens.</s> <s xml:id="echoid-s8571" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8572" xml:space="preserve">Ces détails ſont une intelligence parfaite de la Charpente, de la <lb/>Menuiſerie, de la Serrurerie, des Couvertures de Thuille & </s> <s xml:id="echoid-s8573" xml:space="preserve">d’Ar-<lb/>doiſe, de la Vitrerie, de la Peinture, du Carelage, du Pavé, en un <lb/>mot tout ce qui peut tomber ſous la direction d’un Ingenieur; </s> <s xml:id="echoid-s8574" xml:space="preserve">& </s> <s xml:id="echoid-s8575" xml:space="preserve"><lb/>pour peu qu’on en faſſe enſuite l’aplication aux ouvrages dont il <lb/>eſt parlé dans ceux qui les précédent, je crois qu’en peu de tems <lb/>un jeune Ingenieur ſe rendra capable de ſe bien acquitter des diffe-<lb/>rens Travaux dont les Chefs jugeront à propos de le charger; </s> <s xml:id="echoid-s8576" xml:space="preserve">car <lb/>je ſupoſe qu’il s’eſt mis au fait du premier, du ſecond, & </s> <s xml:id="echoid-s8577" xml:space="preserve">du troi-<lb/>ſiéme Livre, où il a dû apprendre ce qui appartient aux gros Ouvra-<lb/>ges, & </s> <s xml:id="echoid-s8578" xml:space="preserve">qu’il n’eſt plus queſtion que de s’inſtruire des autres plus légers.</s> <s xml:id="echoid-s8579" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8580" xml:space="preserve">Quand on conſtruit un Edifice, il faut donner aux murs des <lb/>épaiſſeurs convenables à la hauteur & </s> <s xml:id="echoid-s8581" xml:space="preserve">à la charge qu’ils doivent por-<lb/>ter, faiſant attention que cette épaiſſeur dépend auſſi de la qualité <lb/>des pierres dont ils ſeront compoſés: </s> <s xml:id="echoid-s8582" xml:space="preserve">ces murs doivent avoir une <lb/>retraite d’un demi pied au-deſſus des fondemens, 3 pouces d’un <lb/>côté & </s> <s xml:id="echoid-s8583" xml:space="preserve">3 pouces de l’autre, & </s> <s xml:id="echoid-s8584" xml:space="preserve">chaque étage ſera auſſi recoupé <lb/>d’environ 3 pouces en dehors & </s> <s xml:id="echoid-s8585" xml:space="preserve">3 pouces en dedans, parce qu’ainſi <lb/>la charge du mur portera à plomb ſans qu’on ſoit obligé de lui don-<lb/>ner de talud; </s> <s xml:id="echoid-s8586" xml:space="preserve">l’on fait une plinthe en dehors à chaque étage, pour <lb/>ne pas rendre ce recoupement ſenſible.</s> <s xml:id="echoid-s8587" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8588" xml:space="preserve">Pour rendre l’ouvrage plus ſolide, les encoignures doivent être <lb/>de pierre de taille autant qu’il eſt poſſible, prenant garde d’en <lb/>éloigner le plus qu’on pourra les fenêtres & </s> <s xml:id="echoid-s8589" xml:space="preserve">les portes, crainte de <lb/>les trop affoiblir; </s> <s xml:id="echoid-s8590" xml:space="preserve">quant aux murs de refends, on leur donnera la <lb/>moitié de l’épaiſſeur de ceux de faces.</s> <s xml:id="echoid-s8591" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8592" xml:space="preserve">L’on obſervera de ne jamais aſſeoir les poûtres ſur des vuides, <lb/>comme ſur des fenêtres ou portes, & </s> <s xml:id="echoid-s8593" xml:space="preserve">qu’elles ne paſſent pas dans <lb/>les cheminées; </s> <s xml:id="echoid-s8594" xml:space="preserve">le vuide doit être aſſis ſur le vuide, comme le plain <lb/>ſur le plain.</s> <s xml:id="echoid-s8595" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8596" xml:space="preserve">Pour la commodité d’un bâtiment, il faut que les apartemens <lb/>ſoient voiſins les uns des autres, bien arrangés; </s> <s xml:id="echoid-s8597" xml:space="preserve">que les principaux, <lb/>comme les ſalles & </s> <s xml:id="echoid-s8598" xml:space="preserve">les chambres, ſoient accompagnées d’une gar-<lb/>de-robe & </s> <s xml:id="echoid-s8599" xml:space="preserve">d’un cabinet, le tout de plain pied: </s> <s xml:id="echoid-s8600" xml:space="preserve">ces apartemens doi-<lb/>vent être proportionnés au ſervice auquel ils ſont deſtinés, & </s> <s xml:id="echoid-s8601" xml:space="preserve"><lb/>quand on eſt libre de ſuivre des juſtes proportions, on ſe reglera <lb/>ſur celles-ci.</s> <s xml:id="echoid-s8602" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8603" xml:space="preserve">Les ſalles auront depuis 22 juſqu’à 24 pieds de largeur, & </s> <s xml:id="echoid-s8604" xml:space="preserve">depuis <lb/>34 juſqu’à 36 de longueur: </s> <s xml:id="echoid-s8605" xml:space="preserve">aux grands bâtimens, la longueur des <pb o="90" file="0420" n="454" rhead="LA SCIENCE DES INGENIEURS,"/> ſalles doit être double de leur largeur, les chambres ſeront quar-<lb/>rées comme étant la figure qui leur convient le mieux, & </s> <s xml:id="echoid-s8606" xml:space="preserve">on pour-<lb/>ra leur donner depuis 22 juſqu’à 24 pieds; </s> <s xml:id="echoid-s8607" xml:space="preserve">quant à la grandeur des <lb/>cabinets & </s> <s xml:id="echoid-s8608" xml:space="preserve">des garde-robes, elle dépend des perſonnes à qui ces <lb/>ſortes d’endroits conviennent plus ou moins.</s> <s xml:id="echoid-s8609" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8610" xml:space="preserve">Les apartemens au rez-de-Chauſſée pourront avoir depuis 13 <lb/>juſqu’à 14 pieds de hauteur, celle du premier étage ſera depuis 12 <lb/>juſqu’à 13, & </s> <s xml:id="echoid-s8611" xml:space="preserve">celle du ſecond, depuis 11 juſqu’à 12, ainſi en di-<lb/>minuant d’un pied ou d’un pied & </s> <s xml:id="echoid-s8612" xml:space="preserve">demi, pour les étages plus <lb/>élevés.</s> <s xml:id="echoid-s8613" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8614" xml:space="preserve">Les proportions qui conviennent le mieux aux grandes & </s> <s xml:id="echoid-s8615" xml:space="preserve">peti-<lb/>tes portes, eſt de leur donner pour hauteur, le double de leur lar-<lb/>geur; </s> <s xml:id="echoid-s8616" xml:space="preserve">les portes, par où doivent paſſer les voitures, auront depuis 8 <lb/>juſqu’à 9 pieds de large; </s> <s xml:id="echoid-s8617" xml:space="preserve">celles des apartemens ordinaires en au-<lb/>ront 3, ou au moins 2 & </s> <s xml:id="echoid-s8618" xml:space="preserve">demi, & </s> <s xml:id="echoid-s8619" xml:space="preserve">celles des grands apartemens & </s> <s xml:id="echoid-s8620" xml:space="preserve"><lb/>des veſtibules pourront avoir depuis 4 juſqu’à 5 pieds.</s> <s xml:id="echoid-s8621" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8622" xml:space="preserve">Dans la face d’un bâtiment, il faut toûjours obſerver que la por-<lb/>te ſoit dans le milieu, autant que cela ſe peut faire: </s> <s xml:id="echoid-s8623" xml:space="preserve">les portes des <lb/>apartemens doivent être de ſuite, & </s> <s xml:id="echoid-s8624" xml:space="preserve">opoſées à une fenêtre lorſ-<lb/>que le bâtiment retourne d’équerre; </s> <s xml:id="echoid-s8625" xml:space="preserve">&</s> <s xml:id="echoid-s8626" xml:space="preserve">, dans les étages qui ſont les <lb/>uns ſur les autres, l’on aura ſoin que les portes ſe répondent à <lb/>plomb, afin que le vuide repoſe ſur le vuide.</s> <s xml:id="echoid-s8627" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8628" xml:space="preserve">Les grandes fenêtres doivent être proportionnées au lieu qu’elles <lb/>éclairent; </s> <s xml:id="echoid-s8629" xml:space="preserve">car, ſi elles ſont trop éloignées & </s> <s xml:id="echoid-s8630" xml:space="preserve">trop petites, elles ren-<lb/>dent le lieu obſcur; </s> <s xml:id="echoid-s8631" xml:space="preserve">ſi elles ſont trop grandes & </s> <s xml:id="echoid-s8632" xml:space="preserve">trop proche les <lb/>unes des autres, elles affoibliſſent le mur dans lequel elles ſont per-<lb/>cées: </s> <s xml:id="echoid-s8633" xml:space="preserve">la meilleure regle eſt de les eſpacer tant plein que vuide, <lb/>c’eſt-à-dire, que la largeur du tremeau ſoit égale à celle de la croi-<lb/>ſée, obſervant que vers les encoigneures (pour ne point affoiblir <lb/>le mur), il y ait de diſtance, de l’angle du bâtiment au tableau <lb/>de la croiſée, un tiers ou un quart plus que la largeur de la croi-<lb/>ſée même.</s> <s xml:id="echoid-s8634" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8635" xml:space="preserve">Les proportions des grandes fenêtres, ou autrement des croiſées, <lb/>dependent de leurs ſituations, ſi elles ſont au rez-de-Chauſſée, au <lb/>premier, au ſecond, ou troiſiéme étage, & </s> <s xml:id="echoid-s8636" xml:space="preserve">de la hauteur de l’étage <lb/>qui eſt different, ſelon la grandeur des édifices.</s> <s xml:id="echoid-s8637" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8638" xml:space="preserve">Toutes les fenêtres des bâtimens particuliers, & </s> <s xml:id="echoid-s8639" xml:space="preserve">des autres de-<lb/>ſtinez aux uſages ordinaires, doivent avoir depuis 4 juſqu’à 5 pieds <lb/>de largeur.</s> <s xml:id="echoid-s8640" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8641" xml:space="preserve">Pour regler généralement leur hauteur, il ſuffira de dire qu’a-<lb/>près avoir pris dans la hauteur de l’étage 3 pieds au plus, qu’il faut <pb o="91" file="0421" n="455" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> donner au mur d’apui, l’on pourra donner le reſte de la hauteur <lb/>ſous ſolives aux croiſées: </s> <s xml:id="echoid-s8642" xml:space="preserve">par exemple, ſi l’étage a 13 pieds de hau-<lb/>teur ſous ſolives, en ayant pris 3 pour l’apui, il en reſtera 10 pour <lb/>la hauteur des croiſées; </s> <s xml:id="echoid-s8643" xml:space="preserve">ainſi à proportion des autres étages qui ſont <lb/>moins élevés.</s> <s xml:id="echoid-s8644" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8645" xml:space="preserve">On fera en ſorte que toutes les fenêtres répondent à plomb les <lb/>unes ſur les autres: </s> <s xml:id="echoid-s8646" xml:space="preserve">s’il y avoit des endroits au ſecond étage ou au <lb/>troiſiéme, où l’on n’auroit pû en faire à cauſe de la diſtribution du <lb/>dedans, qui répondiſſent à celle des étages au-deſſous, il faudroit <lb/>en feindre, afin que la façade du bâtiment ſoit reguliere.</s> <s xml:id="echoid-s8647" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8648" xml:space="preserve">Pour les lucarnes des étages en galatas, elles doivent avoir un <lb/>cinquiéme moins de largeur, que les croiſées de deſſous, & </s> <s xml:id="echoid-s8649" xml:space="preserve">leur <lb/>hauteur doit être environ une fois & </s> <s xml:id="echoid-s8650" xml:space="preserve">demie leur largeur.</s> <s xml:id="echoid-s8651" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8652" xml:space="preserve">La grandeur des cheminées doit être proportionnée à celle des <lb/>places où elles ſont ſituées: </s> <s xml:id="echoid-s8653" xml:space="preserve">les grandes pour les ſalles & </s> <s xml:id="echoid-s8654" xml:space="preserve">ſallons <lb/>auront 6 à 7 pieds d’ouverture entre leurs jambages, & </s> <s xml:id="echoid-s8655" xml:space="preserve">4 à 5, de-<lb/>puis le deſſous de leur plattebande, & </s> <s xml:id="echoid-s8656" xml:space="preserve">environ 2 pieds de profon-<lb/>deur d’atre; </s> <s xml:id="echoid-s8657" xml:space="preserve">les moyennes pour les chambres ſeront environ de 4 <lb/>pieds de largeur, ſur 3 de hauteur & </s> <s xml:id="echoid-s8658" xml:space="preserve">de 18 à 20 pouces de pro-<lb/>fondeur; </s> <s xml:id="echoid-s8659" xml:space="preserve">les petites pour les cabinets peuvent avoir depuis 2 <lb/>pieds juſqu’à 4 de largeur, & </s> <s xml:id="echoid-s8660" xml:space="preserve">le reſte à proportion.</s> <s xml:id="echoid-s8661" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8662" xml:space="preserve">Dans les grands bâtimens, où les murs ont une épaiſſeur conſi-<lb/>derable, on peut y faire paſſer les tuyaux des cheminées; </s> <s xml:id="echoid-s8663" xml:space="preserve">mais, <lb/>quand cette épaiſſeur eſt mediocre, il ne convient pas d’y rien an-<lb/>ticiper, parce qu’on affoibliroit trop les murs de refends ou les <lb/>pignons. </s> <s xml:id="echoid-s8664" xml:space="preserve">Autrefois, les cheminées étoient adoſſées les unes devant <lb/>les autres; </s> <s xml:id="echoid-s8665" xml:space="preserve">mais, comme elles chargeoient les planchers, & </s> <s xml:id="echoid-s8666" xml:space="preserve">ſail-<lb/>loient trop dans les chambres, on a corrigé ce défaut en les ren-<lb/> <anchor type="note" xlink:label="note-0421-01a" xlink:href="note-0421-01"/> geant le long du mur, & </s> <s xml:id="echoid-s8667" xml:space="preserve">en devoyant les tuyaux; </s> <s xml:id="echoid-s8668" xml:space="preserve">mais, comme <lb/>ce devoyement eſt deſagréable à voir, on pratique des armoires <lb/>dans les vuides, ce qui rend la chambre reguliere.</s> <s xml:id="echoid-s8669" xml:space="preserve"/> </p> <div xml:id="echoid-div397" type="float" level="2" n="1"> <note position="right" xlink:label="note-0421-01" xlink:href="note-0421-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>35.</note> </div> <p> <s xml:id="echoid-s8670" xml:space="preserve">Les tuyaux peuvent avoir 3 ou 4 pieds de longueur, ſur 10 12 <lb/>à 15 pouces de largeur, & </s> <s xml:id="echoid-s8671" xml:space="preserve">leur épaiſſeur doit être de languette de <lb/>pierre ou de briques de 4 pouces: </s> <s xml:id="echoid-s8672" xml:space="preserve">quant à la ſituation des chemi-<lb/>nées, je crois qu’il n’eſt pas beſoin de dire, qu’il ne faut jamais les <lb/>adoſſer contre les murs de face, entre les fenêtres, pour des raiſons <lb/>qui ſe font aſſés ſentir; </s> <s xml:id="echoid-s8673" xml:space="preserve">ainſi leur veritable place eſt dans le milieu <lb/>des murs de refends, deſorte qu’elles ſe preſentent en entrant, ſans <lb/>pourtant ſe trouver vis-à-vis la porte, qui doit, comme on l’a déja <lb/>dit, être de côté, pour être d’enfilade avec les autres.</s> <s xml:id="echoid-s8674" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8675" xml:space="preserve">Il faut que les ſouches des cheminées ne cauſent aucune diffor- <pb o="92" file="0422" n="456" rhead="LA SCIENCE DES INGENIEURS,"/> mité au dehors d’un bâtiment, & </s> <s xml:id="echoid-s8676" xml:space="preserve">celles qui ſont ſur le courant du <lb/>comble & </s> <s xml:id="echoid-s8677" xml:space="preserve">iſolées doivent être les plus égales en groſſeur, avec le plus <lb/>de ſimetrie qu’il eſt poſſible, toutes de pareille hauteur, obſervant <lb/>qu’elles ſurmontent le faîte de 3 pieds: </s> <s xml:id="echoid-s8678" xml:space="preserve">leur fermeture doit être <lb/>d’environ 4 à 6 pouces de jour, pour l’échapé de la fumée, ſur <lb/>la longueur proportionnée à celle du tuyau, avec un petit adou-<lb/>ciſſement au-deſſus.</s> <s xml:id="echoid-s8679" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8680" xml:space="preserve">Les eſcaliers faiſant une des principales parties des bâtimens, <lb/>il y auroit beaucoup de choſes à dire ſur le choix de leur place, <lb/>leur grandeur, & </s> <s xml:id="echoid-s8681" xml:space="preserve">leur figure, ſur-tout dans un tems, où il ſemble <lb/>qu’on ne peut rien ajoûter à ce que l’on a fait de merveilleux dans <lb/>ce goût-là. </s> <s xml:id="echoid-s8682" xml:space="preserve">Eſt-il rien de plus beau que de voir des eſcaliers qui ſe <lb/>ſoûtiennent d’eux-mêmes en l’air, par l’admirable invention que l’on <lb/>a trouvée de les évuider dans le milieu? </s> <s xml:id="echoid-s8683" xml:space="preserve">J’avouë, que j’aurois eû un <lb/>extrême plaiſir à traiter ce ſujet, pour examiner, avec autant de <lb/>préciſion qu’on le peut, le Mécaniſme qui doit regner dans la coup-<lb/>pe des pierres, pour y trouver les limons & </s> <s xml:id="echoid-s8684" xml:space="preserve">les apuis en courbe <lb/>rempante, afin que tout puiſſe s’aſſembler & </s> <s xml:id="echoid-s8685" xml:space="preserve">ſe ſoutenir, ſans y <lb/>employer d’autre matiere que<unsure/> la pie<unsure/>rre<unsure/> même; </s> <s xml:id="echoid-s8686" xml:space="preserve">mais, comme cela <lb/>m’auroit mené trop loin, je me contenterai de raporter quelques <lb/>regles generales, qu’on doit obſerver dans la conſtruction des eſca-<lb/>liers ordinaires, d’autant que ceux, qui ſe pratiquent pour la com-<lb/>modité des édifices militaires, n’ont rien de commun avec la ma-<lb/>gnificence de ceux qui peuvent avoir lieu dans les grands édifices.</s> <s xml:id="echoid-s8687" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8688" xml:space="preserve">Pour ne rien interrompre dans la ſuite des apartemens du de-<lb/>dans du corps de logis, on faiſoit autrefois des eſcaliers, au mi-<lb/>lieu de la face en dehors, dans des tours ſeparées; </s> <s xml:id="echoid-s8689" xml:space="preserve">mais, comme <lb/>ces tours defiguroient la ſimetrie exterieure, on a jugé plus à pro-<lb/>pos, par la ſuite, de les placer en dedans, au milieu du corps de <lb/>logis, pour donner la communication à deux apartemens ſeparés <lb/>à droit & </s> <s xml:id="echoid-s8690" xml:space="preserve">à gauche: </s> <s xml:id="echoid-s8691" xml:space="preserve">là, ils étoient bien en vûë & </s> <s xml:id="echoid-s8692" xml:space="preserve">bien éclairés, ne <lb/>gâtoient rien à la décoration; </s> <s xml:id="echoid-s8693" xml:space="preserve">& </s> <s xml:id="echoid-s8694" xml:space="preserve">lors qu’il s’agiſſoit d’un bâti-<lb/>ment ſimple & </s> <s xml:id="echoid-s8695" xml:space="preserve">de peu de profondeur, il ſuffiſoit d’avancer de part <lb/>& </s> <s xml:id="echoid-s8696" xml:space="preserve">d’autre un avant-corps de la largeur de l’eſcalier, ſur chacune <lb/>des faces, pour trouver aſſés de longueur aux rampes, que l’on <lb/>faiſoit ordinairement doubles, afin que pratiquant un paſſage ſous <lb/>le premier palier, à l’endroit de la ſeconde rampe, l’on pût com-<lb/>muniquer de la cour au jardin: </s> <s xml:id="echoid-s8697" xml:space="preserve">cette avance, que l’on faiſoit dans <lb/>le milieu du corps de logis pour placer l’eſcalier, donnoit tant de <lb/>grace au bâtiment, & </s> <s xml:id="echoid-s8698" xml:space="preserve">rendoit l’eſcalier ſi commode, que je ne crois <lb/>pas que l’on puiſſe mieux faire, que de ſuivre cet uſage; </s> <s xml:id="echoid-s8699" xml:space="preserve">quoique <pb o="93" file="0423" n="457" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> dans ces derniers tems on ſe ſoit plûtôt attaché à les placer dans les <lb/>coins, à l’imitation de ce qui ſe pratique en Italie, où l’on affecte <lb/>de faire paſſer ceux qui vont à l’eſcalier par pluſieurs membres en-<lb/>gagés l’un dans l’autre: </s> <s xml:id="echoid-s8700" xml:space="preserve">cependant, comme un eſcalier placé dans <lb/>le milieu occupe la plus belle place du bâtiment, dont on peut <lb/>ſe ſervir plus avantageuſement pour un ſallon, il vaut mieux, quand <lb/>on le peut, le mettre de côté.</s> <s xml:id="echoid-s8701" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8702" xml:space="preserve">Quant à la figure que l’on peut donner aux eſcaliers, ceux, qui <lb/>ſont dans des cages quarrées, ou quarrés longs, conviennent mieux <lb/>aux bâtimens conſiderables, que les autres qui ſeroient diſpoſés <lb/>en rond, en ovale, ou à pans, à moins qu’on n’y ſoit contraint par <lb/>quelque raiſon indiſpenſable.</s> <s xml:id="echoid-s8703" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8704" xml:space="preserve">La grandeur des eſcaliers doit être proportionnée à celle des édi-<lb/>fices à l’uſage deſquels ils ſont deſtinés, & </s> <s xml:id="echoid-s8705" xml:space="preserve">par conſequent doit dé-<lb/>pendre de cette partie d’Architecture, qui fait diſtribuer l’eſpace <lb/>que les apartemens doivent occuper, enſorte que chaque membre <lb/>ſoit proportionné à tout le reſte: </s> <s xml:id="echoid-s8706" xml:space="preserve">la ſeule choſe, quipeut être commu-<lb/>ne aux grands & </s> <s xml:id="echoid-s8707" xml:space="preserve">aux petits eſcaliers, eſt la hauteur des marches <lb/>par raport à leur grandeur, celle des baluſtres & </s> <s xml:id="echoid-s8708" xml:space="preserve">des apuis, parce <lb/>que ce ſont des choſes qui ſervent à des uſages, qui ſe font de mê-<lb/>me par tout.</s> <s xml:id="echoid-s8709" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8710" xml:space="preserve">La moindre largeur, qu’on puiſſe donner à la rampe d’un eſcalier <lb/>principal, eſt de 4 pieds, pour que deux perſonnes puiſſent mon-<lb/>ter & </s> <s xml:id="echoid-s8711" xml:space="preserve">deſcendre de front ſans s’incommoder: </s> <s xml:id="echoid-s8712" xml:space="preserve">la hauteur des apuis <lb/>& </s> <s xml:id="echoid-s8713" xml:space="preserve">des baluſtres doit être au plus de 3 pieds, & </s> <s xml:id="echoid-s8714" xml:space="preserve">au moins de deux <lb/>pieds & </s> <s xml:id="echoid-s8715" xml:space="preserve">demi; </s> <s xml:id="echoid-s8716" xml:space="preserve">quant à la hauteur des marches par raport à leur <lb/>largeur, voici une Regle que Mr. </s> <s xml:id="echoid-s8717" xml:space="preserve">Blondel donne dans ſon Cours <lb/>d’Architecture, que j’ai cru à propos de raporter ici.</s> <s xml:id="echoid-s8718" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8719" xml:space="preserve">La longueur du pas aiſé d’un homme qui marche de niveau eſt <lb/>de 2 pieds, c’eſt-à-dire de 24 pouces, & </s> <s xml:id="echoid-s8720" xml:space="preserve">la hauteur de celui qui <lb/>monte à une échelle dreſſée à plomb n’eſt que d’un pied ou de 12 <lb/>pouces, d’où il paroit que la longueur naturelle du même pas à plomb <lb/>eſt la moitié de la hauteur naturelle du pas étendu de niveau; </s> <s xml:id="echoid-s8721" xml:space="preserve">ainſi, <lb/>pour les joindre l’une avec l’autre, comme il ſe fait dans toutes les <lb/>rempes, il faut que chaque partie en hauteur ſoit par compenſa-<lb/>tion priſe pour deux parties de niveau, & </s> <s xml:id="echoid-s8722" xml:space="preserve">que l’une & </s> <s xml:id="echoid-s8723" xml:space="preserve">l’autre, pour <lb/>compoſer un pas naturel, faſſent enſemble la longueur de 2 pieds <lb/>ou de 24 pouces: </s> <s xml:id="echoid-s8724" xml:space="preserve">pour cet effet, ſi dans une rempe vous ne donnés <lb/>qu’un pouce de hauteur à la marche, il faudra lui donner 22 pou-<lb/>ces de largeur, parce que 22 pouces de niveau avec le pouce de <lb/>hauteur, qui vaut deux pouces de niveau, font enſemble la lon- <pb o="94" file="0424" n="458" rhead="LA SCIENCE DES INGENIEURS,"/> gueur du pas naturel de 24 pouces; </s> <s xml:id="echoid-s8725" xml:space="preserve">ſi la marche à 2 pouces de hau-<lb/>teur qui valent autant que 4 pouces de niveau, elle n’aura que 20 <lb/>pouces de large, qui font enſemble 24 pouces; </s> <s xml:id="echoid-s8726" xml:space="preserve">à 3 pouces de hau-<lb/>teur, qui en valent 6 de niveau, il n’en faudra que 18 de large; </s> <s xml:id="echoid-s8727" xml:space="preserve">à 4 <lb/>pouces de hauteur, qui valent 8 pouces de niveau, il faut 16 pou-<lb/>ces de large; </s> <s xml:id="echoid-s8728" xml:space="preserve">à 5 pouces de hauteur, 14 pouces de giron; </s> <s xml:id="echoid-s8729" xml:space="preserve">à 6 pouces <lb/>de haut, 12 pouces de large; </s> <s xml:id="echoid-s8730" xml:space="preserve">à 7 de haut, 10 de large; </s> <s xml:id="echoid-s8731" xml:space="preserve">à 8 de haut, <lb/>8 de large; </s> <s xml:id="echoid-s8732" xml:space="preserve">à 9 de haut, 6 de large; </s> <s xml:id="echoid-s8733" xml:space="preserve">& </s> <s xml:id="echoid-s8734" xml:space="preserve">ainſi du reſte; </s> <s xml:id="echoid-s8735" xml:space="preserve">ce quiſe trouve <lb/>faire un parfaitement bon effet, comme l’experience le montre.</s> <s xml:id="echoid-s8736" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8737" xml:space="preserve">Pour rendre un Eſcalier commode, il faut prendre garde de ne <lb/>point faire les marches trop élevées: </s> <s xml:id="echoid-s8738" xml:space="preserve">pour cela, il ne faut jamais leur <lb/>donner plus de 6 pouces de hauteur, & </s> <s xml:id="echoid-s8739" xml:space="preserve">moins encore ſi on le peut, <lb/>& </s> <s xml:id="echoid-s8740" xml:space="preserve">régler la largeur du giron ſelon la régle précédente; </s> <s xml:id="echoid-s8741" xml:space="preserve">quand on ne <lb/>peut pas leur donner autant de largeur qu’on le deſire, il faut les <lb/>faire ſaillir d’un pouce, & </s> <s xml:id="echoid-s8742" xml:space="preserve">tailler cette partie en quart de rond.</s> <s xml:id="echoid-s8743" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8744" xml:space="preserve">Il y a des Architectes, qui veulent qu’on faſſe les marches un peu <lb/>inclinées ſur le devant, pour les rendre plus faciles & </s> <s xml:id="echoid-s8745" xml:space="preserve">plus commo-<lb/>des, quand on eſt tellement contraint par l’eſpace qu’on ne peut <lb/>leur donner une largeur convenable; </s> <s xml:id="echoid-s8746" xml:space="preserve">mais, quand cela arrive, il <lb/>vaut beaucoup mieux faire cette pente du ſens opoſé, c’eſt-à-dire <lb/>qu’en montant la pointe du pié ſoit un peu plus baſſe que le talon, <lb/>cette pente aidant tellement à monter, qu’il ſemble que l’on mar-<lb/>che de niveau: </s> <s xml:id="echoid-s8747" xml:space="preserve">on a voulu auſſi faire le giron des marches un peu <lb/>creux dans le milieu, pour rendre la montée plus douce; </s> <s xml:id="echoid-s8748" xml:space="preserve">mais, cette <lb/>pratique eſt trés-dangereuſe, l’experience faiſant voir que ces ſortes <lb/>d’Eſcaliers ſont difficiles à deſcendre, le pied n’y étant jamais aſſuré.</s> <s xml:id="echoid-s8749" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8750" xml:space="preserve">La principale choſe, que l’on doit obſerver en conſtruiſant un <lb/>Eſcalier, eſt de faire enſorte qu’il ſoit bien éclairé; </s> <s xml:id="echoid-s8751" xml:space="preserve">& </s> <s xml:id="echoid-s8752" xml:space="preserve">comme on <lb/>ne peut tirer du jour que des ouvertures qui ſont aſſujetties au reſte <lb/>du bâtiment, il faut bien prendre garde au choix du lieu & </s> <s xml:id="echoid-s8753" xml:space="preserve">à la diſ-<lb/>poſition des rempes, pour qu’il n’y ait aucun endroit qui ne ſoit <lb/>bien éclairé, ſoit par des fenêtres qui répondent au milieu de chaque <lb/>rempe, ſur les paliers, ou par les flancs; </s> <s xml:id="echoid-s8754" xml:space="preserve">mais, il faut éviter que les <lb/>fenêtres ſoient coupées par les rempes, comme cela ſe fait aſſés <lb/>communément, rien n’étant plus diſgracieux à la vûë. </s> <s xml:id="echoid-s8755" xml:space="preserve">Mais ce qu’on <lb/>vient de dire doit ſuffire pour ce ſujet, paſſons à ce qui regarde les <lb/>combles.</s> <s xml:id="echoid-s8756" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8757" xml:space="preserve">Les Architectes ſont aſſés partagés ſur la hauteur qu’il faut don-<lb/>ner aux combles: </s> <s xml:id="echoid-s8758" xml:space="preserve">les uns veulent qu’ils faſſent un triangle équilate-<lb/>ral, les autres un triangle rectangle & </s> <s xml:id="echoid-s8759" xml:space="preserve">iſocelle, d’autres enfin pren-<lb/>nent un milieu entre ces deux-ci & </s> <s xml:id="echoid-s8760" xml:space="preserve">leur donnent pour hauteur les <pb file="0425" n="459"/> <pb file="0425a" n="460"/> <anchor type="figure" xlink:label="fig-0425a-01a" xlink:href="fig-0425a-01"/> <pb file="0426" n="461"/> <pb o="95" file="0427" n="462" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> trois quarts de la largeur du bâtiment; </s> <s xml:id="echoid-s8761" xml:space="preserve">cette proportion eſt fort <lb/>bonne, ne rendant point les toits trop plats ni trop élevés, je l’ai-<lb/>merois mieux qu’aucune autre. </s> <s xml:id="echoid-s8762" xml:space="preserve">Il faut avouër qu’autrefois on les <lb/>faiſoit d’une hauteur exceſſive, comme on le voit encore aujour-<lb/>d’hui à une quantité de bâtimens dont les combles ſont plus élevés <lb/>que les murs de face, défaut qui choque le bon-ſens, & </s> <s xml:id="echoid-s8763" xml:space="preserve">qui n’eſt <lb/>point pardonnable; </s> <s xml:id="echoid-s8764" xml:space="preserve">car, à quoi bon employer une Foreſt de bois <lb/>pous charger inutilement des murs qui ſemblent plier ſous le poids <lb/>dont ils ſont accablés: </s> <s xml:id="echoid-s8765" xml:space="preserve">il eſt vrai qu’on avoit alors deſſein de don-<lb/>ner plus d’écoulement à la neige & </s> <s xml:id="echoid-s8766" xml:space="preserve">aux eaux pluviales; </s> <s xml:id="echoid-s8767" xml:space="preserve">mais, quand <lb/>les toits ont une pente d’environ 50 dégrés, l’experience montre <lb/>que les étages les plus élevés, comme les Greniers, n’en ſont pas <lb/>moins ſecs.</s> <s xml:id="echoid-s8768" xml:space="preserve"/> </p> <div xml:id="echoid-div398" type="float" level="2" n="2"> <figure xlink:label="fig-0425a-01" xlink:href="fig-0425a-01a"> <image file="0425a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0425a-01"/> </figure> </div> <p> <s xml:id="echoid-s8769" xml:space="preserve">Les combles à la Manſarde, que l’on nomme auſſi combles briſés, <lb/>ont fort bonne grace, & </s> <s xml:id="echoid-s8770" xml:space="preserve">c’eſt ce que l’on a imaginé de mieux pour <lb/>la couverture des maiſons qui n’ont guére d’élevation & </s> <s xml:id="echoid-s8771" xml:space="preserve">qui ſont <lb/>iſolées, comme la plûpart de celles que l’on fait à la campagne: <lb/></s> <s xml:id="echoid-s8772" xml:space="preserve">un avantage encore de ces ſortes de combles eſt de rendre l’étage <lb/>en galetas fort habitable, preſque quarré, & </s> <s xml:id="echoid-s8773" xml:space="preserve">les jouës des Lucarnes <lb/>fort petites.</s> <s xml:id="echoid-s8774" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8775" xml:space="preserve">Bullet, pour faire le comble à la Manſarde, décrit un demi, cercle <lb/>dont le diametre eſt ſupoſé égal à la largeur du bâtiment: </s> <s xml:id="echoid-s8776" xml:space="preserve">il diviſe <lb/>enſuite ce demi-cercle en quatre parties égales, pour tracer la moi-<lb/>tié d’un octogone, dont deux des côtés répreſentent le vrai com-<lb/>ble, & </s> <s xml:id="echoid-s8777" xml:space="preserve">les deux autres ce qu’on apelle faux comble.</s> <s xml:id="echoid-s8778" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8779" xml:space="preserve">Mr. </s> <s xml:id="echoid-s8780" xml:space="preserve">Daviller, dans ſon Cours d’Architecture, n’approuve point cet-<lb/>te conſtruction, parce qu’en effet elle rend le toit trop plat; </s> <s xml:id="echoid-s8781" xml:space="preserve">il en pro-<lb/>poſe une autre en termes aſſés obſcurs, qui me paroit auſſi ſujette <lb/>à pluſieurs inconveniens: </s> <s xml:id="echoid-s8782" xml:space="preserve">ainſi, n’ayant rien vû dans les autres de <lb/>ſatisfaiſant ſur ce ſujet, j’ai pris le parti de chercher moi-même ſi <lb/>je ne trouverois pas une méthode de tracer le comble à la Manſar-<lb/>de, qui fût plus reguliere que celles qui ſont venuës à ma connoiſ-<lb/>ſance; </s> <s xml:id="echoid-s8783" xml:space="preserve">la voici.</s> <s xml:id="echoid-s8784" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8785" xml:space="preserve">Il faut décrire un demi-cercle A D B, dont le diamêtre ſera égal <lb/> <anchor type="note" xlink:label="note-0427-01a" xlink:href="note-0427-01"/> à la largeur du bâtiment hors d’œuvre, tracer dans ce demi-cercle <lb/>la moitié d’un décagone regulier A C F G E B, ce qui ſe fait en diviſant <lb/>le raïon en moyenne & </s> <s xml:id="echoid-s8786" xml:space="preserve">extrême raiſon pour avoir la mediane qui <lb/>ſera le côté du décagone, enſuite tirer les deux lignes C A & </s> <s xml:id="echoid-s8787" xml:space="preserve">E B, <lb/>qui exprimeront les côtés du faux comble; </s> <s xml:id="echoid-s8788" xml:space="preserve">& </s> <s xml:id="echoid-s8789" xml:space="preserve">ſi l’on diviſe l’arc C D E, <lb/>en deux également au point D, & </s> <s xml:id="echoid-s8790" xml:space="preserve">qu’on tire les cordes D C & </s> <s xml:id="echoid-s8791" xml:space="preserve">D E, <lb/>elles acheveront la figure A C D E B, de la Manſarde, qui aura fort <pb o="96" file="0428" n="463" rhead="LA SCIENCE DES INGENIEURS,"/> bonne grace, n’étant ni trop élevée ni trop écraſée.</s> <s xml:id="echoid-s8792" xml:space="preserve"/> </p> <div xml:id="echoid-div399" type="float" level="2" n="3"> <note position="right" xlink:label="note-0427-01" xlink:href="note-0427-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>35.</note> </div> <p> <s xml:id="echoid-s8793" xml:space="preserve">Après avoir donné les régles generales qu’on doit ſuivre dans <lb/>la conſtruction des bâtimens, il ſera aiſé d’en faire l’aplication à ceux <lb/>quel’on conſtruit pour l’Etat Major, dans les Citadelles, Forts, & </s> <s xml:id="echoid-s8794" xml:space="preserve">c. <lb/></s> <s xml:id="echoid-s8795" xml:space="preserve">C’eſt pourquoi je paſſerai legerement ſur cet article, & </s> <s xml:id="echoid-s8796" xml:space="preserve">dirai ſeule-<lb/>ment un mot de la diſtribution qui peut convenir pour ces ſortes <lb/>de logemens.</s> <s xml:id="echoid-s8797" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8798" xml:space="preserve">Il faut que le logement d’un Gouverneur ſoit compoſé de trois <lb/>parties principales, ſavoir du corps de logis avec ſa cour, de la <lb/>baſſe-cour, & </s> <s xml:id="echoid-s8799" xml:space="preserve">du jardin: </s> <s xml:id="echoid-s8800" xml:space="preserve">ſon apartement doit être au premier étage, <lb/>& </s> <s xml:id="echoid-s8801" xml:space="preserve">conſiſtera à une anti-chambre, une chambre, un cabinet, & </s> <s xml:id="echoid-s8802" xml:space="preserve">une <lb/>garde-robbe; </s> <s xml:id="echoid-s8803" xml:space="preserve">& </s> <s xml:id="echoid-s8804" xml:space="preserve">ſupoſant que l’eſcalier ſoit dans le milieu du corps <lb/>de logis, l’on doit regler de l’autre côté un ſecond apartement ſem-<lb/>blable à celui-ci pour des gens de conſideration que le Gouverneur <lb/>ſeroit obligé de recevoir, le ſecond étage ſera diſtribué pour les prin-<lb/>cipaux domeſtiques, & </s> <s xml:id="echoid-s8805" xml:space="preserve">le troiſiéme pour les laquais & </s> <s xml:id="echoid-s8806" xml:space="preserve">les fournitu-<lb/>res de la maiſon: </s> <s xml:id="echoid-s8807" xml:space="preserve">dans le rez-de-Chauſſée on y ménagera une ſalle à <lb/>manger, une cuiſine, un garde-manger, une office, une chambre <lb/>& </s> <s xml:id="echoid-s8808" xml:space="preserve">un cabinet pour les Officiers de la Garniſon quand le Gouverneur <lb/>veut déliberer avec eux de quelque choſe qui regarde le ſervice.</s> <s xml:id="echoid-s8809" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8810" xml:space="preserve">Dans la baſſe-cour, on doit y mettre les hangards pour le bois <lb/>de la maiſon; </s> <s xml:id="echoid-s8811" xml:space="preserve">les écuries & </s> <s xml:id="echoid-s8812" xml:space="preserve">les greniers au-deſſus de ces bâtimens <lb/>ſerviront pour les Fourages: </s> <s xml:id="echoid-s8813" xml:space="preserve">à l’égard de la diſpoſition du jardin, <lb/>je n’en parlerai point, puiſqu’elle dépend du lieu, je raporterai ſeu-<lb/>lement le Plan de la maiſon que je viens de décrire, que l’on trou-<lb/>vera ſur la Planche 40. </s> <s xml:id="echoid-s8814" xml:space="preserve">auſſi-bien que ceux des logemens du Lieu-<lb/>tenant de Roi & </s> <s xml:id="echoid-s8815" xml:space="preserve">du Major.</s> <s xml:id="echoid-s8816" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8817" xml:space="preserve">Dans les Villes fortifiées qui ſont habitées depuis long-tems, il <lb/> <anchor type="note" xlink:label="note-0428-01a" xlink:href="note-0428-01"/> y a ordinairement aſſés d’Egliſes pour faire le ſervice divin; </s> <s xml:id="echoid-s8818" xml:space="preserve">mais <lb/>s’il s’agiſſoit d’une Place neuve, il faudroit au moins une Paroiſſe <lb/>dont la grandeur fut proportionné: </s> <s xml:id="echoid-s8819" xml:space="preserve">au nombre des habitans, par <lb/>exemples dans les Villes à ſix Baſtions Royaux, l’Egliſe doit avoir <lb/>35 toiſes de longueur dans œuvre ſur 6 toiſes de largeur, avec <lb/>deux Chapelles de 20 pieds de large ſur 24 de longueur: </s> <s xml:id="echoid-s8820" xml:space="preserve">à droite <lb/>& </s> <s xml:id="echoid-s8821" xml:space="preserve">à gauche de l’Egliſe, il faudra faire des logemens pour le Curé <lb/>& </s> <s xml:id="echoid-s8822" xml:space="preserve">pour le Chapelain, dont la diſtribution auſſi-bien que celle de <lb/>l’Egliſe doit être à peu-près comme on le voit marqué ſur la mê-<lb/>me Planche.</s> <s xml:id="echoid-s8823" xml:space="preserve"/> </p> <div xml:id="echoid-div400" type="float" level="2" n="4"> <note position="left" xlink:label="note-0428-01" xlink:href="note-0428-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>36.</note> </div> <pb file="0429" n="464"/> <pb file="0429a" n="465"/> <figure> <image file="0429a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0429a-01"/> </figure> <pb file="0430" n="466"/> <pb o="97" file="0431" n="467" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> </div> <div xml:id="echoid-div402" type="section" level="1" n="89"> <head xml:id="echoid-head292" xml:space="preserve">CHAPITRE QUATORZIE’ME. <lb/>Qui comprend pluſieurs détails néceſſaires à l’execution des <lb/>Bâtimens.</head> <p> <s xml:id="echoid-s8824" xml:space="preserve"><emph style="sc">APres</emph> avoir donné dans le Chapitre précédent les régles <lb/>generales qu’on doit obſerver dans la conſtruction des bâtimens, <lb/>il me reſte à parler dans celui-ci de tout ce qui apartient à <lb/>leur execution, car ne conſiderer les choſes qu’en gros, c’eſt n’en <lb/>donner qu’une connoiſſance ſurperficielle; </s> <s xml:id="echoid-s8825" xml:space="preserve">il faut entrer dans les <lb/>détails, & </s> <s xml:id="echoid-s8826" xml:space="preserve">il n’y en a pas qui ne ſoient d’une utilité indiſpenſable, <lb/>comme on le va voir.</s> <s xml:id="echoid-s8827" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div403" type="section" level="1" n="90"> <head xml:id="echoid-head293" style="it" xml:space="preserve">Détail de la Charpente, des Combles, des Planchers, de <lb/>la Menuiſerie, des Portes, & Fenêtres.</head> <p> <s xml:id="echoid-s8828" xml:space="preserve">Les combles ſe font toûjours par travées, & </s> <s xml:id="echoid-s8829" xml:space="preserve">l’on apelle travée, <lb/> <anchor type="note" xlink:label="note-0431-01a" xlink:href="note-0431-01"/> la diſtance d’une ferme à l’autre, qui eſt ordinairement de 10 ou <lb/>12 pieds: </s> <s xml:id="echoid-s8830" xml:space="preserve">chaque ferme eſt poſée ſur une poûtre, dont la groſſeur <lb/>dépend de ſa longueur, par conſequent de la largeur du Bâtiment; <lb/></s> <s xml:id="echoid-s8831" xml:space="preserve">& </s> <s xml:id="echoid-s8832" xml:space="preserve">comme les dimenſions de toutes les autres pieces doivent être <lb/>auſſi proportionnées à cette largeur, afin qu’elles ne ſoient ni trop <lb/>fortes ni trop foibles par raport à la portée qu’elles auront, nous <lb/>ſupoſerons qu’il eſt queſtion d’un bâtiment de 30 pieds de largeur <lb/>qui eſt un milieu entre 24 & </s> <s xml:id="echoid-s8833" xml:space="preserve">36 pieds, qu’on peut regarder comme <lb/>la moindre & </s> <s xml:id="echoid-s8834" xml:space="preserve">la plus grande largeur des bâtimens ordinaires.</s> <s xml:id="echoid-s8835" xml:space="preserve"/> </p> <div xml:id="echoid-div403" type="float" level="2" n="1"> <note position="right" xlink:label="note-0431-01" xlink:href="note-0431-01a" xml:space="preserve"><emph style="sc">Planch</emph> <lb/>35.</note> </div> <p> <s xml:id="echoid-s8836" xml:space="preserve">Les piéces qui compoſent une ferme ſont les jambes de force, qui <lb/>ont 8 à 9 pouces de gros; </s> <s xml:id="echoid-s8837" xml:space="preserve">l’entrait, qui ſert à ſoûtenir les arbaleſtriers <lb/>& </s> <s xml:id="echoid-s8838" xml:space="preserve">à aſſembler les jambes de force, en a 8 à 9 poſé de cant; </s> <s xml:id="echoid-s8839" xml:space="preserve">les <lb/>aiſſelieres qui ſervent à lier les jambes de force avec l’entrait, en <lb/>ont 7 à 8; </s> <s xml:id="echoid-s8840" xml:space="preserve">le poinçon 8 en quarré; </s> <s xml:id="echoid-s8841" xml:space="preserve">les contre-fiches quiſervent à ſoû-<lb/>tenir les arbaleſtriers 6 à 7, & </s> <s xml:id="echoid-s8842" xml:space="preserve">les arbaleſtriers 8 à 9.</s> <s xml:id="echoid-s8843" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8844" xml:space="preserve">Les autres piéces d’un comble ſont le faîte, le ſoû-faîte, les pan-<lb/>nes, & </s> <s xml:id="echoid-s8845" xml:space="preserve">les chevrons. </s> <s xml:id="echoid-s8846" xml:space="preserve">L’un & </s> <s xml:id="echoid-s8847" xml:space="preserve">l’autre faîte a 6 à 8 pouces en quarré, & </s> <s xml:id="echoid-s8848" xml:space="preserve"><lb/>les chevrons ordinairement 4 auſſi en quarré, poſés de quatre à la <lb/>latte, c’eſt-à-dire environ à un pied de diſtance. </s> <s xml:id="echoid-s8849" xml:space="preserve">Quand on met <lb/>des plattes-formes ſur l’entablement pour recevoir le pied des che-<lb/>vrons, elles doivent avoir 4 à 8 pouces; </s> <s xml:id="echoid-s8850" xml:space="preserve">& </s> <s xml:id="echoid-s8851" xml:space="preserve">lorſque l’entablement a <lb/>beaucoup de ſaillie, l’on employe des coyeaux pour l’égoût du com- <pb o="98" file="0432" n="468" rhead="LA SCIENCE DES INGENIEURS,"/> ble, afin de conduire les eaux de pluye à quelques pieds au-delà du <lb/>mur de face: </s> <s xml:id="echoid-s8852" xml:space="preserve">ces coyeaux ne ſont autre choſe que des bouts de <lb/>chevrons, dont l’une des extrêmités eſt coupée en bezeau pour être <lb/>apliquée ſur les chevrons mêmes, les pannes repoſent ſur des taſ-<lb/>ſaux, & </s> <s xml:id="echoid-s8853" xml:space="preserve">ces taſſaux ſur l’échantignolle, l’un & </s> <s xml:id="echoid-s8854" xml:space="preserve">l’autre arrêté ſur les <lb/>arbaleſtriers avec des chevilles de bois.</s> <s xml:id="echoid-s8855" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8856" xml:space="preserve">Pour les planchers, je croi qu’il n’eſt pas neceſſaire d’inſinuer <lb/>combien il eſt de conſéquence que les poutres & </s> <s xml:id="echoid-s8857" xml:space="preserve">les ſolives ſoient <lb/>de bon bois coupées depuis pluſieurs années, puiſqu’on n’ignore <lb/>point le danger qu’il y auroit à les employer de mauvaiſe qualité. </s> <s xml:id="echoid-s8858" xml:space="preserve">A <lb/>l’égard des dimenſions des poutres, j’en ai aſſés dit dans le ſecond <lb/>& </s> <s xml:id="echoid-s8859" xml:space="preserve">le troiſiéme Chapitre de ce Livre, pour qu’on ſoit en état de <lb/>juger de la groſſeur qu’il conviendra leur donner.</s> <s xml:id="echoid-s8860" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8861" xml:space="preserve">Les principales piéces de Charpente d’un eſcalier ſont les patins <lb/>ſur leſquels elles ſont poſées, les limons par leſquels on les aſſemble, <lb/>les poteaux qui ſervent à porter les limons, les planchers des paliers, <lb/>les apuis, les baluſtres, & </s> <s xml:id="echoid-s8862" xml:space="preserve">les marches.</s> <s xml:id="echoid-s8863" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8864" xml:space="preserve">Les patins ont 8 à 9 pouces de gros, les poteaux 4 à 6, la groſ-<lb/>ſeur des limons doit ſe régler par rapor@ à leur longueur qui dépend <lb/>de la grandeur de l’eſcalier; </s> <s xml:id="echoid-s8865" xml:space="preserve">mais communément on leur donne 6 à <lb/>8 pouces, poſés de cant: </s> <s xml:id="echoid-s8866" xml:space="preserve">les baluſtres ont 3 ou 4 pouces de groſ-<lb/>ſeur, & </s> <s xml:id="echoid-s8867" xml:space="preserve">les apuis qui ſont poſés deſſus 4 à 6, les marches ont 5 à <lb/>7 pouces poſées ſur le cant, pour les grands eſcaliers, & </s> <s xml:id="echoid-s8868" xml:space="preserve">pour les <lb/>petits, on ne leur en donne que 4 à 6, à l’égard des pieces qui por-<lb/>tent les paliers, il faut qu’elles ſoient de bon bois, parce qu’elles <lb/>ſoûtiennent les rempes dont elles facilitent la communication, c’eſt <lb/>pourquoi on ne peut guéres leur donner moins de 6 à 8 pouces de <lb/>groſſeur & </s> <s xml:id="echoid-s8869" xml:space="preserve">même 8 à 10 quand elles ont une certaine longueur.</s> <s xml:id="echoid-s8870" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8871" xml:space="preserve">Les principaux ouvrages de Menuiſerie, qui ont lieu dans les bâ-<lb/>timens militaires, ſont les portes & </s> <s xml:id="echoid-s8872" xml:space="preserve">les croiſées. </s> <s xml:id="echoid-s8873" xml:space="preserve">On donne ordi-<lb/>nairement aux petites portes d’un apartement un pouce d’épaiſſeur, <lb/>collé & </s> <s xml:id="echoid-s8874" xml:space="preserve">emboëté par en haut & </s> <s xml:id="echoid-s8875" xml:space="preserve">par en bas. </s> <s xml:id="echoid-s8876" xml:space="preserve">Les portes ordinaires <lb/>ont environ 15 lignes d’épaiſſeur, & </s> <s xml:id="echoid-s8877" xml:space="preserve">quand on veut les faire d’aſ-<lb/>ſemblage on leur en donne juſqu’à 18, parce qu’alors on fait une <lb/>moulure en forme de cadre des deux côtés, les panneaux ont un pou-<lb/>ce d’épaiſſeur, les chambranles ont 5 à 6 pouces de largeur, ſur 2 <lb/>pouces d’épaiſſeur ornés de moulures, & </s> <s xml:id="echoid-s8878" xml:space="preserve">l’on fait des embraſe-<lb/>mens aſſemblés à panneaux.</s> <s xml:id="echoid-s8879" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8880" xml:space="preserve">Pour les portes cocheres, on donne à leur battant 8 à 9 pouces <lb/>de largeur ſur 4 d’épaiſſeur, les baſtis qui ſont en dedans ont 3 pou-<lb/>ces, les cadres 4, & </s> <s xml:id="echoid-s8881" xml:space="preserve">les panneaux un pouce & </s> <s xml:id="echoid-s8882" xml:space="preserve">demi.</s> <s xml:id="echoid-s8883" xml:space="preserve"/> </p> <pb o="99" file="0433" n="469" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s8884" xml:space="preserve">Les croiſées ſont ordinairement à panneaux ou à carreaux; </s> <s xml:id="echoid-s8885" xml:space="preserve">on ne <lb/>ſe ſert plus guére aujourd’hui de celles à panneaux, les autres étant <lb/>beaucoup plus belles & </s> <s xml:id="echoid-s8886" xml:space="preserve">d’un meilleur uſage: </s> <s xml:id="echoid-s8887" xml:space="preserve">aux croiſées ordinaires <lb/>de 4 pieds de largeur on donne un pouce & </s> <s xml:id="echoid-s8888" xml:space="preserve">demi ſur 2 & </s> <s xml:id="echoid-s8889" xml:space="preserve">demi aux <lb/>chaſſis dormans, quand on y fait entrer les chaſſis à verre, on leur <lb/>donne 8 pouces; </s> <s xml:id="echoid-s8890" xml:space="preserve">aux maneaux 3 pouces en quarré, un pouce & </s> <s xml:id="echoid-s8891" xml:space="preserve">de-<lb/>mi ſur 2 pouces & </s> <s xml:id="echoid-s8892" xml:space="preserve">demi, aux batans des chaſſis à verre, & </s> <s xml:id="echoid-s8893" xml:space="preserve">aux pe-<lb/>tits bois ou croiſillons, on leur donne environ un pouce en quarré. <lb/></s> <s xml:id="echoid-s8894" xml:space="preserve">Aux grandes croiſées, les chaſſis dormans doivent avoir 3 pouces <lb/>ſur 4, les maneaux de même, les battans des chaſſis à verre 2 pou-<lb/>ces d’épaiſſeur ſur 3 ou 4 pouces de large, & </s> <s xml:id="echoid-s8895" xml:space="preserve">les croiſillons un <lb/>pouce & </s> <s xml:id="echoid-s8896" xml:space="preserve">demi.</s> <s xml:id="echoid-s8897" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8898" xml:space="preserve">Pour empêcher que la pluye qui tombe vers les apuis n’entre <lb/>dans les apartemens, il faut faire la traverſe d’enbas du chaſſis à verre <lb/>aſſés épaiſſe pour y faire des renverſeaux, & </s> <s xml:id="echoid-s8899" xml:space="preserve">pour cela on fait cette <lb/>piéce pardeſſus en quart de rond, & </s> <s xml:id="echoid-s8900" xml:space="preserve">le deſſous en mouchette pen-<lb/>dante pour jetter l’eau à une certaine diſtance.</s> <s xml:id="echoid-s8901" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8902" xml:space="preserve">La traverſe du maneau ſe place plus haut que la moitié de la <lb/>hauteur de la croiſéc d’environ un ſixiéme de cette même hauteur, <lb/>afin que la vûë ne ſoit point barrée par cette traverſe, & </s> <s xml:id="echoid-s8903" xml:space="preserve">que la <lb/>croiſée en ait plus de grace; </s> <s xml:id="echoid-s8904" xml:space="preserve">à l’égard de la hauteur des carreaux, <lb/>il faut leur donner environ un ſixiéme de plus que leur largeur.</s> <s xml:id="echoid-s8905" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div405" type="section" level="1" n="91"> <head xml:id="echoid-head294" style="it" xml:space="preserve">Détail des Couvertures de Thuille & d’Ardoiſe.</head> <p> <s xml:id="echoid-s8906" xml:space="preserve">L’on diſtingue ordinairement trois ſortes de thuille: </s> <s xml:id="echoid-s8907" xml:space="preserve">la premie-<lb/>re eſt celle du grand moule, qui a 13 pouces de long & </s> <s xml:id="echoid-s8908" xml:space="preserve">8 de lar-<lb/>ge, on lui donne 4 pouces de purreau où d’échantillon: </s> <s xml:id="echoid-s8909" xml:space="preserve">la ſecon-<lb/>de eſt le moule bâtard dont nous ne dirons rien, parce qu’il n’eſt <lb/>plus d’uſage: </s> <s xml:id="echoid-s8910" xml:space="preserve">la troiſiéme, celle du petit moule qui a environ 10 <lb/>pouces de long, ſur 6 de large; </s> <s xml:id="echoid-s8911" xml:space="preserve">on lui donne 3 pouces de pureau: <lb/></s> <s xml:id="echoid-s8912" xml:space="preserve">il faut environ 150 thuilles du grand moule, pour faire une toiſe <lb/>quarrée de couverture, & </s> <s xml:id="echoid-s8913" xml:space="preserve">près du double, c’eſt-à-dire, 300 thuil-<lb/>les du petit.</s> <s xml:id="echoid-s8914" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8915" xml:space="preserve">La latte, dont on ſe ſert pour les couvertures de thuille, s’apelle <lb/>latte quarrée, elle doit être de bon bois de chêne de droit fil, ſans <lb/>noeuds ni aubier, elle ſe vend en botte, & </s> <s xml:id="echoid-s8916" xml:space="preserve">la botte contient 50 lat-<lb/>tes de 4 pieds delong chacune; </s> <s xml:id="echoid-s8917" xml:space="preserve">quand les chevrons ſont à un pied de <lb/>diſtance les uns des autres, chaque latte eſt clouée ſur quatre che-<lb/>vrons, avec cinq ou ſix clouds, & </s> <s xml:id="echoid-s8918" xml:space="preserve">comme il reſte trois eſpaces de <lb/>chevrons entre les deux extrêmités d’une latte, on met une contre- <pb o="100" file="0434" n="470" rhead="LA SCIENCE DES INGENIEURS,"/> latte clouée de deux en deux contre-lattes, & </s> <s xml:id="echoid-s8919" xml:space="preserve">la diſtance d’une latte <lb/>du deſſus à celle du deſſous, qui eſt ce qu’on apelle pureau, eſt <lb/>ordinairement d’un tiers de la hauteur de la thuille, priſe au-deſſous <lb/>du crochet.</s> <s xml:id="echoid-s8920" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8921" xml:space="preserve">Quand on employe des thuilles du grand moule, il faut environ <lb/>30 lattes par toiſes quarrées de couverture, 36 quand on ſe ſert de <lb/>celles du petit moule, ce qui demande l’un portant l’autre 190 <lb/>clouds.</s> <s xml:id="echoid-s8922" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8923" xml:space="preserve">Pour que la thuille ſoit bonne, elle doit être faite d’une argille bien <lb/>graſſe, qui ne ſoit ni trop rouge ni trop blanche, & </s> <s xml:id="echoid-s8924" xml:space="preserve">ſi bien cuite, <lb/>que lors qu’on la ſuſpend avec un fil pour la fraper, elle rende un <lb/>ſon clair & </s> <s xml:id="echoid-s8925" xml:space="preserve">net, ce qui n’arrive pas quand elle eſt mal cuite, alors <lb/>elle s’écaille & </s> <s xml:id="echoid-s8926" xml:space="preserve">tombe par morceaux, on obſervera auſſi que la plus <lb/>vielle cuite eſt la meilleure.</s> <s xml:id="echoid-s8927" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8928" xml:space="preserve">Nous avons en France de deux ſortes d’ardoiſe, dont l’une ſe ti-<lb/>re de Meziere & </s> <s xml:id="echoid-s8929" xml:space="preserve">de Charleville, & </s> <s xml:id="echoid-s8930" xml:space="preserve">l’autre vient d’Angers: </s> <s xml:id="echoid-s8931" xml:space="preserve">cette <lb/>derniere eſt beaucoup plus eſtimée que celle de Meziere & </s> <s xml:id="echoid-s8932" xml:space="preserve">de Char-<lb/>leville; </s> <s xml:id="echoid-s8933" xml:space="preserve">mais, en général, la meilleure eſt celle qui eſt la plus noire, <lb/>la plus luiſante eſt la plus ferme.</s> <s xml:id="echoid-s8934" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8935" xml:space="preserve">Il y a à Angers de trois ſortes de grandeur d’ardoiſe: </s> <s xml:id="echoid-s8936" xml:space="preserve">la premie-<lb/>re s’apelle la grande quarrée forte, il en faut environ 200 pour <lb/>faire une toiſe quarrée: </s> <s xml:id="echoid-s8937" xml:space="preserve">la ſeconde s’apelle grande quarrée fine, <lb/>il en faut 180 par toiſe: </s> <s xml:id="echoid-s8938" xml:space="preserve">la troiſiéme s’apelle petite fine, il en faut <lb/>340 par toiſe.</s> <s xml:id="echoid-s8939" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8940" xml:space="preserve">On donne pour pureaux à l’ardoiſe auſſi-bien qu’à la thuille, le <lb/>tiers de ſa hauteur, & </s> <s xml:id="echoid-s8941" xml:space="preserve">les lattes ſur leſquelles elles ſont attachées, <lb/>s’apellent lattes voliſſes, & </s> <s xml:id="echoid-s8942" xml:space="preserve">ces lattes qui ſont beaucoup plus lar-<lb/>ges que celles qui ſervent aux couvertures de thuille, ſe touchent <lb/>preſque l’une l’autre, elles ſe vendent auſſi par bottes, & </s> <s xml:id="echoid-s8943" xml:space="preserve">chaque <lb/>botte contient 25 lattes, une botte fait environ une toiſe & </s> <s xml:id="echoid-s8944" xml:space="preserve">demi <lb/>de converture, la contre-latte eſt de bois de ſciage.</s> <s xml:id="echoid-s8945" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8946" xml:space="preserve">Pour employer un millier d’ardoiſe, ſupoſant qu’elle ait un pied <lb/>de long & </s> <s xml:id="echoid-s8947" xml:space="preserve">5 à 6 pouces de large, qui eſt la plus en uſage, il faut <lb/>150 lattes, & </s> <s xml:id="echoid-s8948" xml:space="preserve">10 ou 12 toiſes de contre-lattes, il faut environ 12 <lb/>clouds pour attacher chaque latte ſur les chevrons, & </s> <s xml:id="echoid-s8949" xml:space="preserve">au moins <lb/>trois clouds pour chaque ardoiſe.</s> <s xml:id="echoid-s8950" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8951" xml:space="preserve">L’on ſe ſert ordinairement de thuille, pour faire les égoûts des <lb/>couvertures d’ardoiſe; </s> <s xml:id="echoid-s8952" xml:space="preserve">&</s> <s xml:id="echoid-s8953" xml:space="preserve">, afin de les rendre de la même couleur, <lb/>on les peint à l’huile.</s> <s xml:id="echoid-s8954" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8955" xml:space="preserve">Le plomb, dont on couvreles enfaîtemens descombles d’ardoiſe <lb/>& </s> <s xml:id="echoid-s8956" xml:space="preserve">des arreſtieres, doit avoir une ligne d’épaiſſeur, & </s> <s xml:id="echoid-s8957" xml:space="preserve">environ 20 <pb o="101" file="0435" n="471" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> pouces de large, on le maintient avec des chrochets poſés le long <lb/>de l’enfaîtement, dont il y en a un ſur chaque chevron: </s> <s xml:id="echoid-s8958" xml:space="preserve">l’enfaîte-<lb/>ment des lucarnes ſe couvre auſſi de plomb de même épaiſſeur, <lb/>mais pas tout à fait ſi large, puiſqu’il ſuffit qu’il ait 15 pouces; </s> <s xml:id="echoid-s8959" xml:space="preserve">ce-<lb/>lui, que l’on employe pour couvrir les œils de bœuf & </s> <s xml:id="echoid-s8960" xml:space="preserve">les nouëds, <lb/>eſt auſſi de même eſpece.</s> <s xml:id="echoid-s8961" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8962" xml:space="preserve">Le plomb pour les cheneaux, que l’on met ſur les enfaîtemens, <lb/>doit avoir une ligne & </s> <s xml:id="echoid-s8963" xml:space="preserve">demi d’épaiſſeur, & </s> <s xml:id="echoid-s8964" xml:space="preserve">18 pouces de largeur, <lb/>& </s> <s xml:id="echoid-s8965" xml:space="preserve">celui des bavettes au-deſſus des mêmes cheneaux eſt auſſi de <lb/>même qualité: </s> <s xml:id="echoid-s8966" xml:space="preserve">il faut donner aux cheneaux environ un pouce de <lb/>pente par toiſe, pour l’écoulement de l’eau, que l’on ſoûtient par <lb/>des crochets poſés auſſi ſur chaque chevron.</s> <s xml:id="echoid-s8967" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8968" xml:space="preserve">Le plomb du tuyau de deſcente doit avoir deux lignes d’épaiſ-<lb/>ſeur, & </s> <s xml:id="echoid-s8969" xml:space="preserve">le tuyau 3 pouces de diamétre, & </s> <s xml:id="echoid-s8970" xml:space="preserve">leurs entonnoirs ou hot-<lb/>tes peſent ordinairement 50 ou 55 livres, & </s> <s xml:id="echoid-s8971" xml:space="preserve">l’on ſoûtient cet en-<lb/>tonnoir & </s> <s xml:id="echoid-s8972" xml:space="preserve">ſon tuyau, par des crochets poſés de diſtance en diſtance.</s> <s xml:id="echoid-s8973" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8974" xml:space="preserve">Quand on ne veut point faire la dépenſe d’un tuyau pour con-<lb/>duire les eaux juſqu’en bas, on fait une goûtiere qui porte l’eau <lb/>environ cinq pieds hors de l’égoût, afin que le pied du mur ne s’en <lb/>reſſente point; </s> <s xml:id="echoid-s8975" xml:space="preserve">cette goûtiere doit être ſoûtenue par une bande <lb/>de fer.</s> <s xml:id="echoid-s8976" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8977" xml:space="preserve">Comme le plomb ſe vend à la livre, l’on ſaura qu’un pied quar-<lb/>ré ſur une ligne d’épaiſſeur peſe environ 5 livres & </s> <s xml:id="echoid-s8978" xml:space="preserve">demi; </s> <s xml:id="echoid-s8979" xml:space="preserve">ſur ce <lb/>principe, il ſera aiſé de connoître le poids des tables de plomb, <lb/>quand on en ſaura l’épaiſſeur.</s> <s xml:id="echoid-s8980" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div406" type="section" level="1" n="92"> <head xml:id="echoid-head295" style="it" xml:space="preserve">Detail de la Vitrerie.</head> <p> <s xml:id="echoid-s8981" xml:space="preserve">Le plus beau Verre qui s’employe en France ſe fait dans la <lb/>Forêt de Leonce, près de Cherbourg en Normandie: </s> <s xml:id="echoid-s8982" xml:space="preserve">il ſe vend <lb/>à la ſomme ou au pannier, qui comprend 24 plats de verre, qui <lb/>ont 30 ou 32 pouces de diamêtre, & </s> <s xml:id="echoid-s8983" xml:space="preserve">le pannier ſe vend preſen-<lb/>tement ſur les lieux 25 livres, après en avoir valu 50 & </s> <s xml:id="echoid-s8984" xml:space="preserve">55 il y <lb/>a quelques années; </s> <s xml:id="echoid-s8985" xml:space="preserve">mais, le Roy en a reglé le prix par un Arrêt <lb/>rendu en 1724. </s> <s xml:id="echoid-s8986" xml:space="preserve">& </s> <s xml:id="echoid-s8987" xml:space="preserve">l’a taxé comme je viens de dire à 25 liv.</s> <s xml:id="echoid-s8988" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8989" xml:space="preserve">Quand les plats ſont entiers ſans aucun accident, & </s> <s xml:id="echoid-s8990" xml:space="preserve">qu’ils ont <lb/>30 à 32 pouces de diamêtre, on peut en tirer environ 5 pieds <lb/>quarrés; </s> <s xml:id="echoid-s8991" xml:space="preserve">ainſi, un pannier, où il n’y a point de plat rompu, peut <lb/>fournir 120 pieds.</s> <s xml:id="echoid-s8992" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8993" xml:space="preserve">Ce ſont ordinairement les Marchands Verriers, qui ſe chargent <lb/>de faire voiturer les panniers de verre aux differens endroits où les <pb o="102" file="0436" n="472" rhead="LA SCIENCE DES INGENIEURS,"/> Vitriers en demandent: </s> <s xml:id="echoid-s8994" xml:space="preserve">& </s> <s xml:id="echoid-s8995" xml:space="preserve">il ya une convention généralement reçûë <lb/>entr’eux, qui eſt que les Marchands Verriers n’indemniſeront les <lb/>Vitriers des plats de verre qui pourront ſe caſſer en chemin, que <lb/>lors qu’il y en aura plus de ſept d’endommagés; </s> <s xml:id="echoid-s8996" xml:space="preserve">c’eſt-à-dire, que <lb/>s’il n’y en avoit que cinq ou ſix, le Vitrier doit recevoir le pannier <lb/>comme ſi tous les plats étoient entiers; </s> <s xml:id="echoid-s8997" xml:space="preserve">mais ſi au contraire il s’en <lb/>trouvoit plus de ſept de rompus, alors les Vitriers ont une indem-<lb/>nité de 20 ſols par plat, deſorte que s’il y en a neuf ou dix de <lb/>rompus, c’eſt neuf ou dix livres que le Marchand doit diminuer.</s> <s xml:id="echoid-s8998" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s8999" xml:space="preserve">Il y a encore une autre ſorte de verre pour la vitrerie que l’on tire <lb/>de Lorraine, qui n’eſt pas à beaucoup près ſi beau que celui de <lb/>Normandie, parce qu’il eſt plein de puſtules & </s> <s xml:id="echoid-s9000" xml:space="preserve">très rude, mais il eſt <lb/>plus épais que le précédent; </s> <s xml:id="echoid-s9001" xml:space="preserve">c’eſt pourquoi on ne laiſſe pas de s’en <lb/>ſervir dans les endroits qui ont beaucoup à ſoufrir du vent, & </s> <s xml:id="echoid-s9002" xml:space="preserve">qui <lb/>ne ſont pas de conſequence; </s> <s xml:id="echoid-s9003" xml:space="preserve">ce verre ſe vend au ballot, & </s> <s xml:id="echoid-s9004" xml:space="preserve">dans <lb/>chaque ballot il y a 20 liens, chaque lien contient ſix tables ou <lb/>plats de verre, dont on ne peut guere tirer de chacun plus de 2 <lb/>pieds & </s> <s xml:id="echoid-s9005" xml:space="preserve">demi de verre en quarré, ainſile ballot ne fournit qu’envi-<lb/>ron 360 pieds quarrés.</s> <s xml:id="echoid-s9006" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9007" xml:space="preserve">Moyennant toutes ces petites connoiſſances, il ſera aiſé de juger <lb/>du prix que doit valoir le pied quarré de verre, en quelque endroit <lb/>du Royaume que l’on ſoit; </s> <s xml:id="echoid-s9008" xml:space="preserve">puis qu’étant prevenu de ce qu’il ſe <lb/>vend ſur les lieux, de ce qu’il en peut couter pour la voiture, & </s> <s xml:id="echoid-s9009" xml:space="preserve"><lb/>de ce que chaque plat peut donner, il n’en faut pas davantage pour <lb/>ſavoir ſi le marché que l’on veut faire eſt raiſonnable ou non: </s> <s xml:id="echoid-s9010" xml:space="preserve">il <lb/>eſt bon de prendre garde que tous les Vitriers du Royaume, ex-<lb/>cepté ceux de Paris, ont en uſage parmi eux un pied qui n’a que 10 <lb/>pouces de roi, & </s> <s xml:id="echoid-s9011" xml:space="preserve">que par conſequent on doit avoir égard à cette <lb/>difference dans les marchés que l’on fait, afin de n’avoir point de <lb/>difficulté pour le toiſé; </s> <s xml:id="echoid-s9012" xml:space="preserve">mais, il faut remarquer que la valeur du pied <lb/>quarré de verre doit dépendre auſſi de la grandeur des carreaux; <lb/></s> <s xml:id="echoid-s9013" xml:space="preserve">que quand ils ſont d’une belle grandeur, comme par exemple de <lb/>10 pouces ſur 8, on n’en peut tirer qu’un petit nombre du même <lb/>plat, & </s> <s xml:id="echoid-s9014" xml:space="preserve">que par conſéquent il faut entrer dans le dechet, qui ſera <lb/>alors plus conſiderable que ſi les carreaux n’étoient pas ſi grands, <lb/>car je ſupoſe toûjours qu’il n’eſt point queſtion des panneaux, & </s> <s xml:id="echoid-s9015" xml:space="preserve">qu’il <lb/>s’agit des croiſées comme on les fait aujourd’hui; </s> <s xml:id="echoid-s9016" xml:space="preserve">enfin j’ajoûte-<lb/>rai, que quand on toiſe une ou pluſieurs croiſées, on ne s’amuſe <lb/>point à compter les carreaux, mais que l’on meſure la largeur & </s> <s xml:id="echoid-s9017" xml:space="preserve">la <lb/>hauteur des fenêtres, fans y comprendre les chaſſis, & </s> <s xml:id="echoid-s9018" xml:space="preserve">qu’on toiſe <lb/>tant plein que vuide, ſans diminuer la difference que cauſent les <lb/>croiſillons ou petits bois.</s> <s xml:id="echoid-s9019" xml:space="preserve"/> </p> <pb o="103" file="0437" n="473" rhead="LIVRE IV. DES EDIFICES MILITAIRES."/> <p> <s xml:id="echoid-s9020" xml:space="preserve">Pour empêcher que l’air ne paſſe entre les carreaux & </s> <s xml:id="echoid-s9021" xml:space="preserve">les croi-<lb/>ſillons, l’on a coutûme d’entourer de plomb les carreaux, ou de <lb/>les coler avec du papier, dont on ſe ſert plus volontiers, parce <lb/>que les carreaux en ſont plus clos: </s> <s xml:id="echoid-s9022" xml:space="preserve">cependant, comme le papier ſe <lb/>détache à la pluye, ce qui oblige de les renouveller de tems en <lb/>tems, on ſe ſert depuis peu d’un maſtic excellent pour cela, & </s> <s xml:id="echoid-s9023" xml:space="preserve">qui <lb/>y étant une fois apliqué ſe conſerveroit des ſiécles entiers ſans <lb/>être renouvellé, ayant la proprieté de ſe durcir à l’air, & </s> <s xml:id="echoid-s9024" xml:space="preserve">comme <lb/>l’uſage de ce maſtic n’eſt connu que de peu de Vitriers, en voici <lb/>la compoſition qui eſt fort ſimple.</s> <s xml:id="echoid-s9025" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9026" xml:space="preserve">On prend du blanc d’Eſpagne, que l’on réduit en poudre, avec <lb/>laquelle on fait une pâte qui ſe petrit avec de l’huile de noix ou de <lb/>lin, & </s> <s xml:id="echoid-s9027" xml:space="preserve">quand cette pâte eſt molle à peu près comme de la terre <lb/>glaiſe, on l’aplique avec un couteau dans la feüillure, où l’on fait <lb/>un cadre d’environ 2 ou 3 lignes de largeur, & </s> <s xml:id="echoid-s9028" xml:space="preserve">comme ce maſtic <lb/>fait un talud, il contribue à conſerver le chaſſis contre la pourri-<lb/>ture, parce que l’eau, qui tombe ſur les feüillures d’embas, coule <lb/>& </s> <s xml:id="echoid-s9029" xml:space="preserve">ne ſejourne point: </s> <s xml:id="echoid-s9030" xml:space="preserve">il eſt ſurprenant de voir que quand ce maſtic <lb/>eſt ſec, il devient ſi dur, & </s> <s xml:id="echoid-s9031" xml:space="preserve">tient les carreaux ſi fermes, qu’il eſt im-<lb/>poſſible de pouvoir les détacher ſans les caſſer par morceaux, ce <lb/>qui cauſe une difficulté quand on veut renouveller ceux qui ſe <lb/>trouvent rompus; </s> <s xml:id="echoid-s9032" xml:space="preserve">mais, on peut empêcher que ce maſtic ne dé-<lb/>vienne ſi dur, en ſe ſervant de l’huile de navette préferablement <lb/>à toute autre; </s> <s xml:id="echoid-s9033" xml:space="preserve">l’experience faiſant voir qu’il ſe détache plus aiſé-<lb/>ment quand on eſt contraint de le faire.</s> <s xml:id="echoid-s9034" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div407" type="section" level="1" n="93"> <head xml:id="echoid-head296" style="it" xml:space="preserve">Détail du Pavé de Grais, de celui de Brique, & de Carreaux.</head> <p> <s xml:id="echoid-s9035" xml:space="preserve">On ſe ſert ordinairement de deux ſortes de pavés de grais, dont <lb/>l’un s’apelle gros pavé, & </s> <s xml:id="echoid-s9036" xml:space="preserve">l’autre pavé d’échantillon; </s> <s xml:id="echoid-s9037" xml:space="preserve">le premier, <lb/>qui peut avoir 7 à 8 pouces en quarré, ſert pour paver les ruës <lb/>& </s> <s xml:id="echoid-s9038" xml:space="preserve">les grands chemins, il s’employe à ſec avec du ſable, on le bat <lb/>& </s> <s xml:id="echoid-s9039" xml:space="preserve">on le dreſſe à la demoiſelle, il y a ſi peu de façon à le mettre en <lb/>uſage, que ce n’eſt preſque point la peine d’en parler.</s> <s xml:id="echoid-s9040" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9041" xml:space="preserve">Le pavé d’échantillon ſe diſtingue auſſi en gros & </s> <s xml:id="echoid-s9042" xml:space="preserve">en petit, le gros <lb/>n’eſt autre choſe que des grais de 7 à 8 pouces fendus en deux, on <lb/>l’employe avec du mortier compoſé de chaux & </s> <s xml:id="echoid-s9043" xml:space="preserve">de ciment, pour <lb/>paver les cours & </s> <s xml:id="echoid-s9044" xml:space="preserve">autres lieux qui demandent quelque attention; <lb/></s> <s xml:id="echoid-s9045" xml:space="preserve">le pavé de petit échantillon eſt le plus ſouvent compoſé de cail-<lb/>loux de couleur bleuâtre, comme il s’en trouve dans certaine Pro-<lb/>vince, il ſert dans les Fortifications pour paver les Platte-For- <pb o="104" file="0438" n="474" rhead="LA SCIENCE DES INGENIEURS."/> mes des tours, le deſſus des Voûtes des Portes de Ville, à l’endroit <lb/>du rempart où ces Voûtes ne ſont point couvertes par un bâti-<lb/>ment, alors on le met en œlig;</s> <s xml:id="echoid-s9046" xml:space="preserve">uvre avec beaucoup de précaution, ſe <lb/>ſervant de mortier de ciment, afin que les cailloux ſoient bien unis <lb/>les uns contre les autres, & </s> <s xml:id="echoid-s9047" xml:space="preserve">qu’après en avoir dirigé les pentes <lb/>qui doivent être au moins d’un pouce par toiſe, les eaux de pluye <lb/>coulant deſſus ſans qu’elles puiſſent s’y arrrêter, ni s’introduire dans <lb/>leurs intervalles.</s> <s xml:id="echoid-s9048" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9049" xml:space="preserve">Il eſt aſſez difficile d’eſtimer au juſte la quantité de cailloux qu’il <lb/>faut par toiſe quarrée, parce que cela dépend de leur groſſeur, qui <lb/>eſt ſujette à une grande varieté; </s> <s xml:id="echoid-s9050" xml:space="preserve">cependant, l’experience montre <lb/>qu’avec une toiſe cube, on peut faire dix toiſes quarrées de pavé, <lb/>& </s> <s xml:id="echoid-s9051" xml:space="preserve">qu’il faut environ 100 gros pavés de 7 a 8 pouces en quarré l’un <lb/>portant l’autre, pour faire une toiſe quarrée, & </s> <s xml:id="echoid-s9052" xml:space="preserve">deux tombereaux <lb/>de ſable.</s> <s xml:id="echoid-s9053" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9054" xml:space="preserve">Les planchers des Cazernes ſe pavent le plus ſouvent avec de <lb/>la brique, parce que les carreaux n’y reſteroient pas long-tems <lb/>entiers: </s> <s xml:id="echoid-s9055" xml:space="preserve">il eſt vrai que cela charge beaucoup les poutres & </s> <s xml:id="echoid-s9056" xml:space="preserve">les ſo-<lb/>lives; </s> <s xml:id="echoid-s9057" xml:space="preserve">c’eſt pourquoi il faut y avoir égard, pour ne pas faire les <lb/>planchers trop foibles.</s> <s xml:id="echoid-s9058" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9059" xml:space="preserve">Quand on ſe ſert de briques de 10 pouces de longueur, ſur 5 de <lb/>large & </s> <s xml:id="echoid-s9060" xml:space="preserve">2 & </s> <s xml:id="echoid-s9061" xml:space="preserve">demi d’épaiſſeur, il en faut 90 poſées de plat pour <lb/>faire une toiſe quarrée, & </s> <s xml:id="echoid-s9062" xml:space="preserve">environ deux tiers d’un ſac de chaux, <lb/>& </s> <s xml:id="echoid-s9063" xml:space="preserve">le ſable à proportion.</s> <s xml:id="echoid-s9064" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9065" xml:space="preserve">Si l’on veut poſer les briques de cant, pour rendre le pavé d’un <lb/>meilleur uſage, il en faut le double que quand elles ſont poſées de <lb/>plat, c’eſt-à-dire 180 pour une toiſe quarrée, un ſac de chaux, & </s> <s xml:id="echoid-s9066" xml:space="preserve"><lb/>le ſable à proportion.</s> <s xml:id="echoid-s9067" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9068" xml:space="preserve">Pour paver les chambres des pavillons, on ſe ſert ordinairement <lb/>de carreaux, qui peuvent être de differente grandeur & </s> <s xml:id="echoid-s9069" xml:space="preserve">figure, les <lb/>plus communs ſont quarrés, & </s> <s xml:id="echoid-s9070" xml:space="preserve">ont ſix pouces de côté, d’autres en <lb/>ont 8 à 9; </s> <s xml:id="echoid-s9071" xml:space="preserve">de ceux-ci il en faut 64 pour faire une toiſe quarrée, <lb/>deux tiers d’un ſac de chaux, & </s> <s xml:id="echoid-s9072" xml:space="preserve">le ſable à proportion; </s> <s xml:id="echoid-s9073" xml:space="preserve">il y en a <lb/>d’autres à ſix pans, & </s> <s xml:id="echoid-s9074" xml:space="preserve">qui étant employés font un meilleur effet <lb/>que les quarrés: </s> <s xml:id="echoid-s9075" xml:space="preserve">les échantillons les plus ordinaires de ces derniers <lb/>ſont de 8, de 6, & </s> <s xml:id="echoid-s9076" xml:space="preserve">de 4 pouces de diamétre; </s> <s xml:id="echoid-s9077" xml:space="preserve">quand on les employe <lb/>dans les bâtimens qui ont pluſieurs étages, il eſt bon de ſe ſervir <lb/>des plus grands au rez-de-Chauſſée, & </s> <s xml:id="echoid-s9078" xml:space="preserve">des autres plus petits aux <lb/>étages ſuperieurs, parce qu’ayant moins d’épaiſſeur, ils ne char-<lb/>gent pas tant les planchers.</s> <s xml:id="echoid-s9079" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div408" type="section" level="1" n="94"> <head xml:id="echoid-head297" style="it" xml:space="preserve">Fin du quatriéme Livre.</head> <pb file="0439" n="475"/> <figure> <image file="0439-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0439-01"/> </figure> </div> <div xml:id="echoid-div409" type="section" level="1" n="95"> <head xml:id="echoid-head298" xml:space="preserve">LA SCIENCE <lb/>DES INGENIEURS <lb/>DANS LA CONDUITE DES TRAVAUX <lb/>DE FORTIFICATION.</head> <head xml:id="echoid-head299" xml:space="preserve">LIVRE CIN QUIE’ME.</head> <head xml:id="echoid-head300" style="it" xml:space="preserve">Où l’on enſeigne tout ce qui peut appartenir à la Décoration <lb/>des Edifices.</head> <p> <s xml:id="echoid-s9080" xml:space="preserve">L’ART de décorer les Edifices renferme tant de <lb/>choſes interreſſantes & </s> <s xml:id="echoid-s9081" xml:space="preserve">utiles, que j’ai crû ne pou-<lb/>voir me diſpenſer d’en donner un petit Traité, qui <lb/>contint ſuccinctement les Maximes les plus aprou-<lb/>vées des meilleurs Architectes: </s> <s xml:id="echoid-s9082" xml:space="preserve">je ſai bien que la <lb/>plûpart des Ingenieurs s’y attachent peu, les autres parties de <lb/>leur métier étant aſſés étenduës pour les occuper entierement; <lb/></s> <s xml:id="echoid-s9083" xml:space="preserve">cependant, ſi l’on fait reflexion que ce n’eſt que par la connoiſ-<lb/>ſance des Ordres d’Architecture qu’on peut acquerir le bon goût <lb/>& </s> <s xml:id="echoid-s9084" xml:space="preserve">cette grace qui ſied ſi bien dans les Ouvrages mêmes les plus <pb o="2" file="0440" n="476" rhead="LA SCIENCE DES INGENIEURS,"/> ruſtiques, l’on conviendra qu’il ſe rencontre mille occaſions d’en <lb/>faire uſage, ſoit pour orner les Portes des Villes, les Guerites de <lb/>Maçonnerie, & </s> <s xml:id="echoid-s9085" xml:space="preserve">les Edifices Militaires en general, puiſqu’il faut ne-<lb/>ceſſairement certains principes pour profiler ſelon les regles les par-<lb/>ties d’un entablement, & </s> <s xml:id="echoid-s9086" xml:space="preserve">même celles de la moindre corniche: </s> <s xml:id="echoid-s9087" xml:space="preserve">d’ail-<lb/>leurs, quelle ſatisfaction n’eſt-ce pas pour ceux qui ſe piquent d’avoir <lb/>quelque connoiſſance au-deſſus des autres, de pouvoir juger du <lb/>mérite des ſuperbes monumens qui marquent de toute part la ma-<lb/>gnificence de nos Roys; </s> <s xml:id="echoid-s9088" xml:space="preserve">& </s> <s xml:id="echoid-s9089" xml:space="preserve">que pourroit-on penſer ſi on les voyoit <lb/>au milieu du Château de Verſailles y admirer commele Peuple les <lb/>beautés qu’on y trouve, ſans en avoir un ſentiment plus éclairé? <lb/></s> <s xml:id="echoid-s9090" xml:space="preserve">Il eſt des choſes que l’on ne peut ignorer ſans ſe faire tort, on n’ex-<lb/>cuſe point aiſément un galant homme qui n’a nulle connoiſſance de <lb/>la Fable, ni de l’Hiſtoire, à plus forte raiſon ſeroit-on en droit de <lb/>trouver à redire ſi un Ingenieur ne ſavoit pas faire la difference d’un <lb/>Ordre Toſcan d’avec un Corinthien, ce n’eſt pas que je penſe qu’il <lb/>y en ait beaucoup dans ce cas, je ſuis fort éloigné d’un préjugé ſi <lb/>injuſte, les entretiens que j’ai eus avec pluſieurs ſur cette matiere <lb/>m’ont fait voir qu’il s’en trouvoit d’auſſi capables de conſtruire un <lb/>Palais, qu’une demi-Lune ou une contre-Garde, je veux ſeulement <lb/>deſabuſer ceux qui veulent s’attacher aux Fortifications de l’opinion <lb/>que Vitruve, Palladio, Vignole, & </s> <s xml:id="echoid-s9091" xml:space="preserve">Scamozzy, ſont des Auteurs qui <lb/>ne les intereſſent pas, s’imaginant qu’il leur ſuffit de ſavoir tracer <lb/>ſur le Papier un front de Poligonne pour être d’habiles gens, & </s> <s xml:id="echoid-s9092" xml:space="preserve">que <lb/>tout ce qui ne tend pas directement à la maniere de fortifier les <lb/>Places regarde le miniſtere des Architectes plûtôt que le leur, <lb/>il y en a même qui croiroient déroger s’ils s’y apliquoient, comme <lb/>s’il y avoit plus de gloire de faire bâtir un corps de Cazernes qu’un <lb/>Portique.</s> <s xml:id="echoid-s9093" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9094" xml:space="preserve">Malgré tout ce que je pourrois dire pour juſtifier les raiſons que <lb/>j’ai eûes de parler de la Décoration, ce n’a pas été ſans peine que je <lb/>me ſuis déterminé à écrire ſur un ſujet ſi délicat, les Bibliotheques <lb/>étant remplies d’une grande quantité de Livres qui ſemblent avoir <lb/>épuiſé la matiere; </s> <s xml:id="echoid-s9095" xml:space="preserve">car, il faut avoüer que cette Science, après avoir <lb/>éte long-tems enſevelie ſous les ruines des Edifices antiques, eſt <lb/>parvenue ajourd’hui à un dégré de perfection qui la met au-<lb/>deſſus de ſon ancienne ſplendeur, & </s> <s xml:id="echoid-s9096" xml:space="preserve">qu’il faut être bien habile ou <lb/>bien téméraire, pour ajoûter quelque choſe aux préceptes que tant <lb/>de grands hommes nous ont laiſſés, auſſi n’eſt-ce pas mon deſſein, <lb/>n’ayant eû en vûë que de rendre mon Ouvrage complet, en évitant <lb/>aux Lecteurs la peine d’étudier un grand nombre de Traités, où il <pb o="3" file="0441" n="477" rhead="LIVRE V. DE LA DE’CORATION."/> n’eſt pas aiſé de faire un bon choix des meilleures régles. </s> <s xml:id="echoid-s9097" xml:space="preserve">Ainſi, à <lb/>le bien prendre, ce n’eſt pas moi qui vais parler, mais plûtôt, Vi-<lb/>truve, Palladio, Vignole, Scamozzy, Chambray, Perrault, Blon-<lb/>del, Daviler, & </s> <s xml:id="echoid-s9098" xml:space="preserve">tous les autres Architectes, dont les Ouvrages ont <lb/>de la réputation: </s> <s xml:id="echoid-s9099" xml:space="preserve">ſouvent même je me ſers de leurs propres termes; <lb/></s> <s xml:id="echoid-s9100" xml:space="preserve">n’ayant pas voulu imiter ceux qui changent les expreſſions d’un Au-<lb/>teur, pour s’en approprier les penſées. </s> <s xml:id="echoid-s9101" xml:space="preserve">Cependant, comme la plûpart <lb/>des Architectes ont leur méthode particuliere de déterminer les pro-<lb/>portions des Ordres, j’ai ſuivi celui qui m’a parû le moins confus <lb/>& </s> <s xml:id="echoid-s9102" xml:space="preserve">le plus goûté du Public; </s> <s xml:id="echoid-s9103" xml:space="preserve">je veux dire Vignole, qui peut paſſer <lb/>avec raiſon pour le plus célebre d’entre les modernes: </s> <s xml:id="echoid-s9104" xml:space="preserve">ſa mé-<lb/>thode eſt aiſée, ſes régles ſont générales, & </s> <s xml:id="echoid-s9105" xml:space="preserve">ce qui en augmen-<lb/>te le prix, c’eſt qu’il les a tirées de ces grands Originaux qu’on <lb/>ne peut ſe diſpenſer de prendre pour modéle, ſans tomber dans <lb/>des deffauts groſſiers; </s> <s xml:id="echoid-s9106" xml:space="preserve">comme cela n’eſt que trop arrivé à la con-<lb/>fuſion de l’Architecture gothique, qui, ſans avoir eû d’autre fon-<lb/>dement que l’ignorance & </s> <s xml:id="echoid-s9107" xml:space="preserve">un caprice ridicule, a rempli le monde <lb/>d’une quantité prodigieuſe d’Edifices qui n’étoient ornés que par des <lb/>colifichets, dont le mauvais goût fait tort à la mémoire de nos <lb/>Peres, qui ont pû admirer des choſes ſi bizarres, tandis qu’ils <lb/>rencontroient par-tout des veſtiges de ces beaux monumens qui <lb/>font tant d’honneur aux Grecs & </s> <s xml:id="echoid-s9108" xml:space="preserve">aux Romains; </s> <s xml:id="echoid-s9109" xml:space="preserve">& </s> <s xml:id="echoid-s9110" xml:space="preserve">peut-être <lb/>ſerions-nous encore dans le même aveuglemé<unsure/>nt, ſi le Roi Fran-<lb/>çois I. </s> <s xml:id="echoid-s9111" xml:space="preserve">en rapellant en France les Sciences & </s> <s xml:id="echoid-s9112" xml:space="preserve">les belles Lettres <lb/>n’avoit occaſionné le rétabliſſement de l’ancienne Architecture: </s> <s xml:id="echoid-s9113" xml:space="preserve"><lb/>mais ce nefut point d’abord ſans peine que les yeux accoûtumés aux <lb/>Ouvrages gothiques pûrent ſe faire à de nouveaux objets, & </s> <s xml:id="echoid-s9114" xml:space="preserve">comme <lb/>dit Mr. </s> <s xml:id="echoid-s9115" xml:space="preserve">Blondel, (c’eſt alors que l’on vit qu’il eſt bien plus facile <lb/>de corriger les deffauts de l’ignorance ſans préſomption, que d’a-<lb/>porter du remede à ceux qui viennent d’une fauſſe capacité,) les <lb/>nouveaux Architectes mépriſerent tout ce que l’uſage avoit intro-<lb/>duit de défectueux & </s> <s xml:id="echoid-s9116" xml:space="preserve">d’impertinent, & </s> <s xml:id="echoid-s9117" xml:space="preserve">ne ſongerent plus qu’à s’inſ-<lb/>truire dans l’examen des anciens Edifices qui reſtoient en Italie & </s> <s xml:id="echoid-s9118" xml:space="preserve"><lb/>particulierement à Rome; </s> <s xml:id="echoid-s9119" xml:space="preserve">ils en meſurerent exactement les parties, <lb/>& </s> <s xml:id="echoid-s9120" xml:space="preserve">enchantez de l’harmonie qui regnoit entre elles, ils mirent toute <lb/>leur aplication à recouvrer les regles que les Romains avoient apriſes <lb/>des Grecs, & </s> <s xml:id="echoid-s9121" xml:space="preserve">heureuſement ils trouverent dans Vitruve dequoi leur <lb/>abreger beaucoup de chemin. </s> <s xml:id="echoid-s9122" xml:space="preserve">Cet Auteur, qui eſt le ſeul qui nous <lb/>reſte des anciens, après avoir été fort negligé, fut enfin lû par les <lb/>gens du métier: </s> <s xml:id="echoid-s9123" xml:space="preserve">& </s> <s xml:id="echoid-s9124" xml:space="preserve">comme ſi la Nature avoit voulu dédommager l’Ar-<lb/>chitecture de l’injuſtice qu’on lui avoit faite pendant tant de ſiécles, <pb o="4" file="0442" n="478" rhead="LA SCIENCE DES INGENIEURS,"/> les Roys ſucceſſeurs de François I. </s> <s xml:id="echoid-s9125" xml:space="preserve">la reçûrent avec tant d’acueil, <lb/>& </s> <s xml:id="echoid-s9126" xml:space="preserve">donnerent tant de marques de leurs bienfaits à ceux qui la culti-<lb/>voient, qu’on vit en peu de tems des morceaux dignes des plus <lb/>grands Maîtres; </s> <s xml:id="echoid-s9127" xml:space="preserve">& </s> <s xml:id="echoid-s9128" xml:space="preserve">les choſes en ſont venues à ce point, que ſi les <lb/>Romains du tems d’Auguſte pouvoient renaître, ils viendroient en <lb/>France, pour y admirer ce qu’on ne trouvoit autrefois que chez <lb/>eux.</s> <s xml:id="echoid-s9129" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9130" xml:space="preserve">Quoique j’aye ſuivi Vignole par préférence à cauſe de l’extrême <lb/>facilité de ſes meſures, je n’ai pas laiſſé, ſans vouloir m’écarter de <lb/>ſes ſentimens, de tirer des autres ce qui pouvoit corriger ou per-<lb/>fectionner certaines parties que cet Auteur avoit negligé ou rendu <lb/>équivoques par le peu d’étenduë qu’il donne à l’explication de ſes <lb/>principes; </s> <s xml:id="echoid-s9131" xml:space="preserve">je n’ai pas voulu non plus comme lui me borner aux <lb/>cinq Ordres, j’ai crû qu’il étoit à propos de les accompagner de tou-<lb/>tes les regles particulieres qui pouvoient y avoir raport, pour ren-<lb/>dre ce ſujet auſſi inſtructif qu’on peut le ſouhaiter dans un ouvrage <lb/>comme celui-ci, dont le principal objet n’eſt point de faire des <lb/>Architectes, mais des Ingenieurs capables de tout ce qui regarde <lb/>leur métier.</s> <s xml:id="echoid-s9132" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9133" xml:space="preserve">Quoique le mot d’Ordre en general puiſſe s’apliquer à une infinité <lb/>de choſes differentes, pour ſignifier qu’elles ſont dans l’arangement <lb/>qui leur convient, les Anciens l’ont affecté particulierement à <lb/>l’Architecture, pour exprimer l’harmonie de pluſieurs parties, qui <lb/>par leurs diſpoſitions font un tout qui plait, & </s> <s xml:id="echoid-s9134" xml:space="preserve">ſurprend agréable-<lb/>ment le coup d’œil: </s> <s xml:id="echoid-s9135" xml:space="preserve">& </s> <s xml:id="echoid-s9136" xml:space="preserve">comme les moulures & </s> <s xml:id="echoid-s9137" xml:space="preserve">les ornemens dont <lb/>on ſe ſert peuvent s’employer de diverſes manieres, & </s> <s xml:id="echoid-s9138" xml:space="preserve">en plus ou <lb/>moins grande quantité, les Ordres ont été réduits à cinq, ſavoir le <lb/>Toſcan, le Dorique, l’Ionique, le Corinthien, & </s> <s xml:id="echoid-s9139" xml:space="preserve">le Compoſite.</s> <s xml:id="echoid-s9140" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9141" xml:space="preserve">Les Grecs, qui ont inventé les Ordres, n’en ont jamais eu que <lb/>trois, le Dorique, l’Ionique, & </s> <s xml:id="echoid-s9142" xml:space="preserve">le Corinthien: </s> <s xml:id="echoid-s9143" xml:space="preserve">les deux autres, <lb/>c’eſt-à-dire le Toſcan & </s> <s xml:id="echoid-s9144" xml:space="preserve">le Compoſé, ont été imaginés par les Ro-<lb/>mains, qui n’en ont pas fait eux-mêmes grand cas; </s> <s xml:id="echoid-s9145" xml:space="preserve">puiſqu’au raport <lb/>de pluſieurs Auteurs célebres, il reſte peu de veſtiges de l’Ordre <lb/>Toſcan, parce qu’ils l’ont trouvé trop groſſier, & </s> <s xml:id="echoid-s9146" xml:space="preserve">n’ont point em-<lb/>ployé ſeparément le Compoſé, ayant toûjours donné la preference <lb/>au Corinthien: </s> <s xml:id="echoid-s9147" xml:space="preserve">en effet, il eſt bien mieux proportionné; </s> <s xml:id="echoid-s9148" xml:space="preserve">car, comme <lb/>le remarque Scamozzy, le chapiteau de l’Ordre Compoſite eſt <lb/>trop maſſif, & </s> <s xml:id="echoid-s9149" xml:space="preserve">ne s’accorde point avec la délicateſſe des autres par-<lb/>ties. </s> <s xml:id="echoid-s9150" xml:space="preserve">Mr. </s> <s xml:id="echoid-s9151" xml:space="preserve">de Chambray, dans ſon Paralelle de l’Architecture antique <lb/>avec la moderne, ſepare abſolument les trois Ordres Grecs des <lb/>deux Romains, & </s> <s xml:id="echoid-s9152" xml:space="preserve">fait voir avec beaucoup de diſcernement, com- <pb o="5" file="0443" n="479" rhead="LIVRE V. DE LA DE’CORATION."/> bien ces Ordres ſont inferieurs à la beauté des autres; </s> <s xml:id="echoid-s9153" xml:space="preserve">car le Toſ-<lb/>can ne peut être employé ſeul que dans les Ouvrages maſſifs & </s> <s xml:id="echoid-s9154" xml:space="preserve"><lb/>groſſiers, quoiqu’on puiſſe s’en ſervir ſans répugnance aux Portes <lb/>des Villes, ou à quelque endroit qui demande du ruſtique. </s> <s xml:id="echoid-s9155" xml:space="preserve">Le Com-<lb/>poſé étant pris des autres Ordres, & </s> <s xml:id="echoid-s9156" xml:space="preserve">n’ayant rien de particulier, n’en <lb/>devroit point faire un à part: </s> <s xml:id="echoid-s9157" xml:space="preserve">l’on prétend même, que la licence que <lb/>les Romains ont priſe en imaginant cet Ordre, a été en partie cauſe de <lb/>la confuſion qui s’eſt introduite dans l’Architecture gothique; </s> <s xml:id="echoid-s9158" xml:space="preserve">car l’a-<lb/>mour de la nouveauté a fait qu’on ne s’en eſt pas tenu là, les ou-<lb/>vriers les plus ignorans s’étant crû en droit de faire tous les chan-<lb/>gemens dont ils on pû s’aviſer.</s> <s xml:id="echoid-s9159" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9160" xml:space="preserve">Pour dire un mot de l’origine des Ordres, l’on prétend que le Do-<lb/>rique fut inventé par un nommé Dorus, qui l’employa le premier <lb/>dans Argos à la conſtruction du ſuperbe Temple qui fut érigé à la <lb/>Déeſſe Junon, & </s> <s xml:id="echoid-s9161" xml:space="preserve">qu’enſuite on en bâtit un autre dans Delos à Apol-<lb/>lon, à l’occaſion duquel on imagina les Trigliphes pour répreſenter <lb/>la Lire dont ce Dieu étoit l’Inventeur.</s> <s xml:id="echoid-s9162" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9163" xml:space="preserve">L’Hiſtoire ne nous aprend pas poſitivement quel eſt l’Auteur de <lb/>l’Ordre Ionique: </s> <s xml:id="echoid-s9164" xml:space="preserve">l’on ſait ſeulement, qu’un nommé Ion Athenien fut <lb/>choiſi par ceux de ſa Nation, pour être chef de treize colonies qui <lb/>furent envoyées dans l’Aſie mineure, où ils s’établirent dans la Carie <lb/>nommée enſuite Ionie, pour faire honneur à Ion qui en avoit fait <lb/>la conquête, & </s> <s xml:id="echoid-s9165" xml:space="preserve">qui y fit bâtir treize grandes Villes, dont la plus <lb/>conſidérable étoit Ephéſe, où l’on éleva un Temple à Diane, dont <lb/>l’Ordre étoit different du Dorique; </s> <s xml:id="echoid-s9166" xml:space="preserve">& </s> <s xml:id="echoid-s9167" xml:space="preserve">comme ce Temple eut enſuite <lb/>beaucoup de réputation, y ayant toute aparence que c’eſt celui qui <lb/>a été brûlé par Eroſtrate, on nomma le deſſein, ſelon lequel il avoit <lb/>été conſtruit, l’Ordre Ionique, pour marquer la Province où il avoit <lb/>pris naiſſance.</s> <s xml:id="echoid-s9168" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9169" xml:space="preserve">Vitruve, en parlant de l’Ordre Corinthien, dit qu’il fut inventé par <lb/>Callimachus Sculpteur Athenien, qui demeuroit alors proche la <lb/>Ville de Corinthe une des plus conſidérables de la Grece; </s> <s xml:id="echoid-s9170" xml:space="preserve">& </s> <s xml:id="echoid-s9171" xml:space="preserve">com-<lb/>me il y a aparence que c’eſt-là où cet Ordre fut mis en uſage pour <lb/>la premiere fois, c’eſt ſans doute ce qui lui en a fait retenir le nom: <lb/></s> <s xml:id="echoid-s9172" xml:space="preserve">d’autres prétendent que le chapiteau Corinthien tire ſon origine du <lb/>Temple de Salomon; </s> <s xml:id="echoid-s9173" xml:space="preserve">au reſte, il en ſera tout ce qu’on voudra: </s> <s xml:id="echoid-s9174" xml:space="preserve">mais <lb/>il faut convenir que l’Ordre Corinthien eſt le chef-d’œuvre de l’Ar-<lb/>chitecture, & </s> <s xml:id="echoid-s9175" xml:space="preserve">que tout ce qu’on a pû faire de mieux juſqu’ici a été <lb/>ſeulement d’atteindre à la beauté que lui ont donnée ſes premiers <lb/>Inventeurs.</s> <s xml:id="echoid-s9176" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9177" xml:space="preserve">Les Romains, après s’être rendus Maîtres de l’Univers, enrichi- <pb o="6" file="0444" n="480" rhead="LA SCIENCE DES INGENIEURS,"/> rent Rome, non ſeulement de tous les Tréſors que leur procu-<lb/>rerent leurs conquêtes, mais introduiſirent encore tout ce qu’ils <lb/>trouverent d’admirable chés les étrangers, particulierement leur <lb/>maniere de bâtir, que des ouvriers leurs Eſclaves leur enſeignoient; <lb/></s> <s xml:id="echoid-s9178" xml:space="preserve">& </s> <s xml:id="echoid-s9179" xml:space="preserve">bien-tôt ſurpaſſant en magnificence toutes les autres nations, <lb/>leurs édifices devinrent dans la ſuite les plus excellens modéles <lb/>qu’on pût imiter: </s> <s xml:id="echoid-s9180" xml:space="preserve">& </s> <s xml:id="echoid-s9181" xml:space="preserve">pour encherir ſur ce qu’ils tenoient des Grecs, <lb/>ils voulurent ſe faire un Ordre plus riche que tous les autres; </s> <s xml:id="echoid-s9182" xml:space="preserve">& </s> <s xml:id="echoid-s9183" xml:space="preserve">com-<lb/>me de ce tems-là la matiere étoit déja épuiſée, ils prirent des <lb/>autres Ordres ce qui leur parut de plus beau, & </s> <s xml:id="echoid-s9184" xml:space="preserve">en firent celui <lb/>qu’on a nommé depuis Compoſé. </s> <s xml:id="echoid-s9185" xml:space="preserve">La ſeule Province de Toſcane, <lb/>ne voulant rien devoir aux Grecs ſes plus cruels ennemis, inventa <lb/>l’Ordre qui a depuis conſervé ſon nom; </s> <s xml:id="echoid-s9186" xml:space="preserve">&</s> <s xml:id="echoid-s9187" xml:space="preserve">, pour ſe paſſer abſolument <lb/>des autres, il falut le deſtituer d’ornemens, ſe contentant de décorer <lb/>les Temples & </s> <s xml:id="echoid-s9188" xml:space="preserve">les autres Edifices, qui devoient avoir quelque relief, <lb/>de Colomnes ſans pieds-d’eſtaux, & </s> <s xml:id="echoid-s9189" xml:space="preserve">d’un ſimple Chapiteau ſurmon-<lb/>té par l’entablement, dont la corniche & </s> <s xml:id="echoid-s9190" xml:space="preserve">les autres parties ſont des <lb/>plus unies.</s> <s xml:id="echoid-s9191" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9192" xml:space="preserve">Je viens de placer les Ordres dans le Rang qui leur convient le <lb/>mieux, quoique cela ne tire ici à aucune conſequence; </s> <s xml:id="echoid-s9193" xml:space="preserve">mais, quand <lb/>il ſera queſtion de les décrire & </s> <s xml:id="echoid-s9194" xml:space="preserve">de les expliquer en détail, je me <lb/>conformerai à l’arangement de Vignole, puiſque c’eſt l’Auteur que <lb/>je me ſuis propoſé de ſuivre, c’eſt-à-dire, je commencerai par <lb/>l’Ordre Toſcan comme le plus ſimple, & </s> <s xml:id="echoid-s9195" xml:space="preserve">qu’enſuite je raporterai le <lb/>Dorique, l’Ionique, le Corinthien, & </s> <s xml:id="echoid-s9196" xml:space="preserve">le Compoſite pour le dernier.</s> <s xml:id="echoid-s9197" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div410" type="section" level="1" n="96"> <head xml:id="echoid-head301" style="it" xml:space="preserve">Explication des Termes propres aux Ordres d’ Architecture.</head> <p> <s xml:id="echoid-s9198" xml:space="preserve">Quoique je donne à la fin du ſecond Volume un Dictionnaire <lb/>fort ample, pour expliquer tous les Termes d’Architecture, auſſi-<lb/>bien que les autres qui auront lieu dans les differens Traitez que <lb/>l’on verra par la ſuite; </s> <s xml:id="echoid-s9199" xml:space="preserve">j’ai cru qu’il étoit à propos de définir pre-<lb/>ſentement ceux qui ſont employés aux Ordres, afin qu’aidé de ce <lb/>qu’on trouvera écrit ſur les trois premieres Planches, l’on puiſſe ſe <lb/>former une idée juſte des proprietés de chaque moulure, & </s> <s xml:id="echoid-s9200" xml:space="preserve">que <lb/>ſe trouvant expliqués de ſuite, ſans être interrompus par d’autres <lb/>termes, comme cela arrive dans un Dictionnaire, on ait plus de <lb/>facilité à les retenir.</s> <s xml:id="echoid-s9201" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9202" xml:space="preserve">Doucine, Cimaiſe, ou Gueule droite, eſt une moulure dont le contour <lb/>a une ſinuoſité, ce qui fait que cette moulure change de nom ſui-<lb/>vant la ſituation où elle ſe trouve: </s> <s xml:id="echoid-s9203" xml:space="preserve">quand la partie d’enhaut eſt con- <pb o="7" file="0445" n="481" rhead="LIVRE V. DE LA DE’CORATION."/> cave, elle ſe nomme Gueule droite ou Doucine; </s> <s xml:id="echoid-s9204" xml:space="preserve">& </s> <s xml:id="echoid-s9205" xml:space="preserve">quand elle eſt con-<lb/>vexe, on la nomme Gueule renverſée ou Talon.</s> <s xml:id="echoid-s9206" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9207" xml:space="preserve">Liſteau, Filet, ou Ourelet, eſt une petite bande qu’on met entre les <lb/>moulures pour les ſeparer, & </s> <s xml:id="echoid-s9208" xml:space="preserve">empêcher qu’elles ne ſe confondent.</s> <s xml:id="echoid-s9209" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9210" xml:space="preserve">Ove, quart de rond, ou échine, eſt une moulure dont le contour eſt <lb/>un quart de cercle, & </s> <s xml:id="echoid-s9211" xml:space="preserve">qui fait une partie eſſentielle des ornemens.</s> <s xml:id="echoid-s9212" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9213" xml:space="preserve">Couronne, Larmier, ou Goutiere, eſt un membre de la corniche, <lb/>qui ſert à faire écouler l’eau loin du mur, & </s> <s xml:id="echoid-s9214" xml:space="preserve">on apelle Mouchette <lb/>le petit rebord qui pend en bas.</s> <s xml:id="echoid-s9215" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9216" xml:space="preserve">Modillons, ſont des pieces qui s’avancent ſous le plafond des cor-<lb/>niches pour en ſoûtenir la ſaillie, & </s> <s xml:id="echoid-s9217" xml:space="preserve">font un des plus beaux orne-<lb/>mens de cette partie de l’entablement; </s> <s xml:id="echoid-s9218" xml:space="preserve">les Anciens s’en ſont ſervis <lb/>pour repréſenter des bouts de chevrons.</s> <s xml:id="echoid-s9219" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9220" xml:space="preserve">Aſtragale, eſt un petit membre rond, dont le contour a ordinai-<lb/>rement la figure d’un demi-cercle: </s> <s xml:id="echoid-s9221" xml:space="preserve">on l’apelle communement Cha-<lb/>pelet, quand il eſt taillé en forme de petites boules, qui reſſem-<lb/>blent à des grains de chapelet enfilés.</s> <s xml:id="echoid-s9222" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9223" xml:space="preserve">Denticule, eſt un membre quarré, recoupé par pluſieurs entail-<lb/>les, qui ſemblent vouloir repreſenter des dents: </s> <s xml:id="echoid-s9224" xml:space="preserve">elles s’employent <lb/>ordinairement dans la corniche Ionique & </s> <s xml:id="echoid-s9225" xml:space="preserve">Corinthienne; </s> <s xml:id="echoid-s9226" xml:space="preserve">Vitruve <lb/>apelle Metoche l’eſpace vuide qui eſt entre chaque Denticule.</s> <s xml:id="echoid-s9227" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9228" xml:space="preserve">Trigliphe, eſt un ornement compoſé de trois litels ou jambes, qui <lb/>ſont ſeparés par deux canelures: </s> <s xml:id="echoid-s9229" xml:space="preserve">cet ornement ne s’employe que <lb/>dans la Friſe de l’Ordre Dorique.</s> <s xml:id="echoid-s9230" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9231" xml:space="preserve">Metope, eſt l’eſpace entre deux Trigliphes; </s> <s xml:id="echoid-s9232" xml:space="preserve">cet eſpace eſt ordi-<lb/>nairement quarré, ayant autant de hauteur qu’il y a de diſtance <lb/>d’un Trigliphe à l’autre.</s> <s xml:id="echoid-s9233" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9234" xml:space="preserve">Soffite, ou Plafond, eſt le deſſous de ce qui eſt ſuſpendu: </s> <s xml:id="echoid-s9235" xml:space="preserve">ainſi <lb/>l’on dit le Soffite d’un Architrave ou d’un Larmier.</s> <s xml:id="echoid-s9236" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9237" xml:space="preserve">La Friſe, eſt une des principales parties de l’entablement, dont elle <lb/>occupe le milieu, étant toûjours entre la corniche & </s> <s xml:id="echoid-s9238" xml:space="preserve">l’architrave: <lb/></s> <s xml:id="echoid-s9239" xml:space="preserve">cette partie a été nommée Friſe, à cauſe que les ornemens qu’on <lb/>y fait reſſemblent à de la broderie.</s> <s xml:id="echoid-s9240" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9241" xml:space="preserve">Architrave, eſt la premiere partie de l’entablement, poſée ſur les <lb/>colomnes ou pilaſtres, ou ſimplement ſur un mur de face, quand <lb/>on veut le terminer par un entablement: </s> <s xml:id="echoid-s9242" xml:space="preserve">l’Architrave à le bien pren-<lb/>dre repreſente les poutres, dont les extrémités étant bien apuyées <lb/>portent dans leur longueur les parties d’une façade, ou tout autre <lb/>corps élevé verticalement; </s> <s xml:id="echoid-s9243" xml:space="preserve">ainſi l’Architrave n’eſt autre choſe que <lb/>ce qu’on apelle communement Sabliere ou Poitrail.</s> <s xml:id="echoid-s9244" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9245" xml:space="preserve">Abaque, eſt une partie qui ſert dans l’Ordre Corinthien à repre- <pb o="8" file="0446" n="482" rhead="LA SCIENCE DES INGENIEURS,"/> ſenter la thuille qui couvroit le pannier, autour duquel s’élevoient <lb/>les feuilles d’Acanthe qui ont donné lieu à l’invention du Chapiteau <lb/>de cet Ordre: </s> <s xml:id="echoid-s9246" xml:space="preserve">les ouvriers l’apellent Tailloirs.</s> <s xml:id="echoid-s9247" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9248" xml:space="preserve">Volute eſt un ornement qui fait la partie eſſentielle du chapiteau <lb/>Ionique: </s> <s xml:id="echoid-s9249" xml:space="preserve">cette Volute eſt contournée comme une ligne ſpiralle, <lb/>& </s> <s xml:id="echoid-s9250" xml:space="preserve">a été imaginée par les Anciens pour repreſenter les boucles des <lb/>cheveux qui pendoient aux côtez du viſage des femmes.</s> <s xml:id="echoid-s9251" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9252" xml:space="preserve">Cathete de la Volute n’eſt autre choſe qu’une ligne perpendiculai-<lb/>re, qui paſſe par l’œil de la volute, & </s> <s xml:id="echoid-s9253" xml:space="preserve">ſert à la décrire & </s> <s xml:id="echoid-s9254" xml:space="preserve">à en dé-<lb/>terminer la hauteur; </s> <s xml:id="echoid-s9255" xml:space="preserve">l’on met auſſi de petites volutes aux chapi-<lb/>teaux Corinthiens, mais celles-ci s’apellent Helices.</s> <s xml:id="echoid-s9256" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9257" xml:space="preserve">Galbe, on dit qu’un membre ou morceau d’Architecture ſe ter-<lb/>mine en forme de galbe, lorſqu’il s’élargit doucement par en haut, <lb/>comme font les feuilles d’une fleur.</s> <s xml:id="echoid-s9258" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9259" xml:space="preserve">Fuſt ou Tige d’une colomne, doit ſe prendre pour le corps de la <lb/>colomne, depuis ſa baſe juſqu’à ſon chapiteau.</s> <s xml:id="echoid-s9260" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9261" xml:space="preserve">Canelures ſont des eſpeces de côtes ou liſtaux exprimées ſur une <lb/>colomne, par le moyen des creux que l’on y pratique; </s> <s xml:id="echoid-s9262" xml:space="preserve">ces cane-<lb/>lures ſe font à vive arrête dans l’Ordre Dorique, mais elles ne ſont <lb/>guére aprouvées, à cauſe qu’elles ſont trop foibles, par conſequent <lb/>trop ſujettes à être rompuës.</s> <s xml:id="echoid-s9263" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9264" xml:space="preserve">Eſcape, Conge, ou Retraite, eſtun trait concave qui joint le nud <lb/>de la colomne avec ſa baſe ou ſon chapiteau: </s> <s xml:id="echoid-s9265" xml:space="preserve">ce trait s’apelle auſſi <lb/>Fruit quand il s’agit de l’eſcape d’en bas, pour ſignifier que la co-<lb/>lomne ſort de ſa baſe, commence à monter & </s> <s xml:id="echoid-s9266" xml:space="preserve">à s’échaper en haut.</s> <s xml:id="echoid-s9267" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9268" xml:space="preserve">Baſe d’une Colomne eſt la partie ſur laquelle elle eſt poſée.</s> <s xml:id="echoid-s9269" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9270" xml:space="preserve">Tore eſt une eſpece de gros anneau dans la baſe d’une colomne, <lb/>qui ſemble repreſenter les cercles de fer, dont on fortifie les ex-<lb/>trémités des troncs d’arbres, qui ſervent à ſoûtenir quelque corps <lb/>fort preſant.</s> <s xml:id="echoid-s9271" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9272" xml:space="preserve">Scotie, c’eſt la partie creuſe qui eſt entre deux tores, que les ou-<lb/>vriers apellent Nacelle à cauſe de ſa cavité; </s> <s xml:id="echoid-s9273" xml:space="preserve">l’on nomme Cavet la <lb/>moitié de la Scotie.</s> <s xml:id="echoid-s9274" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9275" xml:space="preserve">La Plinthe eſt un membre quarré & </s> <s xml:id="echoid-s9276" xml:space="preserve">plat, que quelques uns <lb/>nomment Orle ou Ourelet: </s> <s xml:id="echoid-s9277" xml:space="preserve">elle ſe trouve toûjours dans les baſes <lb/>des colomnes.</s> <s xml:id="echoid-s9278" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9279" xml:space="preserve">Plinthe dans le chapiteau Toſcan eſt la partie que l’on nomme <lb/>Tailloirs dans ceux des autres Ordres.</s> <s xml:id="echoid-s9280" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9281" xml:space="preserve">Piédeſtal eſt un corps quarré de figure parallelipipede, qui ſert à <lb/>élever une colomne ou une ſtatuë au-deſſus du rez-de-Chauſſée: <lb/></s> <s xml:id="echoid-s9282" xml:space="preserve">le Piédeſtal a ſa baſe & </s> <s xml:id="echoid-s9283" xml:space="preserve">ſa corniche; </s> <s xml:id="echoid-s9284" xml:space="preserve">& </s> <s xml:id="echoid-s9285" xml:space="preserve">le corps parallelipipede, qui <lb/>eſt entre ces deux parties, eſt nommé Tronc ou Dé du Piédeſtal.</s> <s xml:id="echoid-s9286" xml:space="preserve"/> </p> <pb o="9" file="0447" n="483" rhead="LIVRE V. DE LA DE’CORATION."/> </div> <div xml:id="echoid-div411" type="section" level="1" n="97"> <head xml:id="echoid-head302" xml:space="preserve">CHAPITRE PREMIER.</head> <head xml:id="echoid-head303" style="it" xml:space="preserve">Où l’on explique les proprietés des Moulures & de <lb/>leurs Ornemens.</head> <p> <s xml:id="echoid-s9287" xml:space="preserve">IL y a deux ſortes de moulures, ſçavoir les quarrées & </s> <s xml:id="echoid-s9288" xml:space="preserve">les ron-<lb/> <anchor type="note" xlink:label="note-0447-01a" xlink:href="note-0447-01"/> des; </s> <s xml:id="echoid-s9289" xml:space="preserve">les quarrées ſont faites avec des lignes droites, les rondes <lb/>avec des portions de cercle ou autres lignes courbes: </s> <s xml:id="echoid-s9290" xml:space="preserve">de ces mou-<lb/>lures il y en a de grandes & </s> <s xml:id="echoid-s9291" xml:space="preserve">de petites; </s> <s xml:id="echoid-s9292" xml:space="preserve">les grandes ſont les Douci-<lb/>nes, Oves, Gorges, Talons, Tores, & </s> <s xml:id="echoid-s9293" xml:space="preserve">Scoties; </s> <s xml:id="echoid-s9294" xml:space="preserve">les petites ſont les Filets, <lb/>Aſtragales, & </s> <s xml:id="echoid-s9295" xml:space="preserve">Conges: </s> <s xml:id="echoid-s9296" xml:space="preserve">ces petites moulures ſervent à ſéparer & </s> <s xml:id="echoid-s9297" xml:space="preserve">à cou-<lb/>ronner les grandes, pour leur donner auſſi plus de relief & </s> <s xml:id="echoid-s9298" xml:space="preserve">de <lb/>diſtinction. </s> <s xml:id="echoid-s9299" xml:space="preserve">Les unes & </s> <s xml:id="echoid-s9300" xml:space="preserve">les autres ſe tracent differemment, ſelon la <lb/>diſtance d’où elles doivent être vûës, puiſque c’eſt de cette diſtan-<lb/>ce que dependent les ſaillies ou retraites qu’on leur donne.</s> <s xml:id="echoid-s9301" xml:space="preserve"/> </p> <div xml:id="echoid-div411" type="float" level="2" n="1"> <note position="right" xlink:label="note-0447-01" xlink:href="note-0447-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>37.</note> </div> <p> <s xml:id="echoid-s9302" xml:space="preserve">Les plus belles moulures ſont celles dont le contour eſt parfait, <lb/>comme le Quart-de-rond & </s> <s xml:id="echoid-s9303" xml:space="preserve">le Cavet, qui ſe tracent par le moyen d’un <lb/>quart-de-cercle, ainſi qu’on le peut voir dans les figures 6, 7, & </s> <s xml:id="echoid-s9304" xml:space="preserve"><lb/>8. </s> <s xml:id="echoid-s9305" xml:space="preserve">Le Talon & </s> <s xml:id="echoid-s9306" xml:space="preserve">la Doucine marquez par les figures 9, 10, 11, & </s> <s xml:id="echoid-s9307" xml:space="preserve"><lb/>12, ont auſſi fort bonne grace; </s> <s xml:id="echoid-s9308" xml:space="preserve">pour les tracer, il faut être pre-<lb/>venu qu’à ces quatre moulures, on leur donne autant de ſaillie que <lb/>de hauteur, c’eſt-à-dire que AB eſt égal à BC, & </s> <s xml:id="echoid-s9309" xml:space="preserve">qu’enſuite on ti-<lb/>re la ligne AC, qu’on diviſe en deux également au point F; </s> <s xml:id="echoid-s9310" xml:space="preserve">ſur cha-<lb/>que partie égalle CF & </s> <s xml:id="echoid-s9311" xml:space="preserve">FA comme baſe, on fait un triangle équi-<lb/>lateral, l’un en dehors, l’autre en dedans, afin d’avoir les points <lb/>D & </s> <s xml:id="echoid-s9312" xml:space="preserve">E, qui ſervent de centre pour décrire deux portions de cer-<lb/>cles, qui compoſent enſemble la ſinuoſité de cette moulure, qui <lb/>eſt la même dans les figures 9 & </s> <s xml:id="echoid-s9313" xml:space="preserve">10, l’une étant droite & </s> <s xml:id="echoid-s9314" xml:space="preserve">l’autre <lb/>renverſée: </s> <s xml:id="echoid-s9315" xml:space="preserve">les Cimaiſes ou Talons, que l’on voit exprimés par les fi-<lb/>gures 11 & </s> <s xml:id="echoid-s9316" xml:space="preserve">12, ſe tracent auſſi par le moyen du triangle équilate-<lb/>ral, avec cette difference cependant, que la portion du cercle GH <lb/>qui répond à la partie ſaillante G, eſt convexe, & </s> <s xml:id="echoid-s9317" xml:space="preserve">que l’autre qui ré-<lb/>pond à la partie rentrante I eſt concave, au lieu que dans les deux <lb/>autres figures, c’eſt tout le contraire.</s> <s xml:id="echoid-s9318" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9319" xml:space="preserve">Le contour des aſtragales ſe fait ordinairement avec les trois <lb/>quarts, ou les deux tiers, de la circonference d’un cercle, au lieu <lb/>que le gros & </s> <s xml:id="echoid-s9320" xml:space="preserve">le petit tore font formez par une demi circonferen- <pb o="10" file="0448" n="484" rhead="LA SCIENCE DES INGENIEURS,"/> ce juſte, ainſi qu’on le voit marqué aux figures 3 & </s> <s xml:id="echoid-s9321" xml:space="preserve">4; </s> <s xml:id="echoid-s9322" xml:space="preserve">à l’égard de <lb/>la Scotie & </s> <s xml:id="echoid-s9323" xml:space="preserve">du Tore corrompu marquez par les figures 5 & </s> <s xml:id="echoid-s9324" xml:space="preserve">13, je ne <lb/>ſache point qu’on ait aucune regle geometrique, pour tracer la <lb/>concavité de l’une & </s> <s xml:id="echoid-s9325" xml:space="preserve">la convexité de l’autre; </s> <s xml:id="echoid-s9326" xml:space="preserve">c’eſt à ceux qui font <lb/>des modeles de profils de contourner ces moulures, de façon qu’el-<lb/>les ne faſſent point un effet deſagreable.</s> <s xml:id="echoid-s9327" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9328" xml:space="preserve">Pour faire de beaux profils, il faut prendre garde de ne les point <lb/>trop charger de moulures, & </s> <s xml:id="echoid-s9329" xml:space="preserve">n’en point repeter de ſemblables <lb/>imediatement l’une après l’autre; </s> <s xml:id="echoid-s9330" xml:space="preserve">pour cela, il faut les mêler alter-<lb/>nativement de quarrées & </s> <s xml:id="echoid-s9331" xml:space="preserve">de rondes, de maniere que les grandes <lb/>ſoient ſeparées des autres, par des petites, qui les faſſent valoir par <lb/>leur comparaiſon; </s> <s xml:id="echoid-s9332" xml:space="preserve">de ces grandes moulures, il faut qu’il y en ait <lb/>qui dominent comme le Larmier dansla Corniche, qui eſt la mou-<lb/>lure la plus eſſentielle, évitant ſur-tout l’égalité des moulures dans <lb/>les profils, c’eſt pourquoi on les fait de differente hauteur, & </s> <s xml:id="echoid-s9333" xml:space="preserve">pour <lb/>donner là-deſſus quelques regles genérales, on aura attention, qu’une <lb/>moulure qui en couronne une autre ne doit avoir pour hauteur que <lb/>la moitié de celle qui eſt au-deſſous, ni moins d’un tiers; </s> <s xml:id="echoid-s9334" xml:space="preserve">de même <lb/>le Filet ſur l’Aſtragale, & </s> <s xml:id="echoid-s9335" xml:space="preserve">l’Aſtragale ſous l’Ove, ne doit être moin-<lb/>dre du quart, ni plus haut que le tiers de l’Ove; </s> <s xml:id="echoid-s9336" xml:space="preserve">mais on jugera <lb/>mieux de toutes ces proportions, par celles qui accompagnent les <lb/>profils que nous expliquerons par la ſuite.</s> <s xml:id="echoid-s9337" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9338" xml:space="preserve">Quant aux ornemens, il faut ſavoir les placer avec choix & </s> <s xml:id="echoid-s9339" xml:space="preserve">avec <lb/>goût; </s> <s xml:id="echoid-s9340" xml:space="preserve">car comme il y a des parties qui ſont ornées naturellement, à <lb/>cauſe du beau mélange de leurs moulures, il ſeroit à craindre que ſi <lb/>l’on vouloit y ajoûter quelque-choſe, on fit naître la confuſion plû-<lb/>tôt que la bonne grace; </s> <s xml:id="echoid-s9341" xml:space="preserve">il faut prendre garde auſſi que les ornemens <lb/>conviennent au genre de l’édifice, & </s> <s xml:id="echoid-s9342" xml:space="preserve">faire enſorte qu’ils ſoient na-<lb/>turels, ſans en faire d’imaginaires, de groteſques, & </s> <s xml:id="echoid-s9343" xml:space="preserve">de bizarres: </s> <s xml:id="echoid-s9344" xml:space="preserve">la <lb/>nature fournit aſſés d’objets, ſans qu’il ſoit neceſſaire de faire travail-<lb/>ler d’imagination; </s> <s xml:id="echoid-s9345" xml:space="preserve">les fleurs, les animaux, & </s> <s xml:id="echoid-s9346" xml:space="preserve">les fruits ſont en aſſés <lb/>grande abondance pour varier les ſujets: </s> <s xml:id="echoid-s9347" xml:space="preserve">le tout eſt de les placer <lb/>aux endroits qui leur conviennent le mieux; </s> <s xml:id="echoid-s9348" xml:space="preserve">& </s> <s xml:id="echoid-s9349" xml:space="preserve">c’eſt en ceci, com-<lb/>me dans le reſte, que l’Architecture ancienne eſt toûjours admi-<lb/>rable.</s> <s xml:id="echoid-s9350" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9351" xml:space="preserve">Pour éviter la confuſion, il faut que les ornemens ſoient inter-<lb/>rompus, c’eſt-à-dire, qu’entre deux moulures ornées, il y en ait <lb/>une liſſée ou toute unie; </s> <s xml:id="echoid-s9352" xml:space="preserve">& </s> <s xml:id="echoid-s9353" xml:space="preserve">lors qu’il ſe rencontre deux moulures <lb/>d’un même profil, les orner differemment, pour donner de la va-<lb/>rieté, faiſant enſorte que chaque partie qui ſert à la décoration <lb/>ſoit ornée avec proportion, évitant qu’il y en ait d’entierement nuë, <pb o="11" file="0449" n="485" rhead="LIVRE V. DE LA DE’CORATION."/> tandis que les autres ſeroient enrichies avec profuſion. </s> <s xml:id="echoid-s9354" xml:space="preserve">Les orne-<lb/>mens doivent auſſi convenir aux Ordres: </s> <s xml:id="echoid-s9355" xml:space="preserve">les plus riches ne doi-<lb/>vent être employés qu’aux Corinthien & </s> <s xml:id="echoid-s9356" xml:space="preserve">Compoſé, & </s> <s xml:id="echoid-s9357" xml:space="preserve">les moins <lb/>recherchés à l’Ionique; </s> <s xml:id="echoid-s9358" xml:space="preserve">à l’égard du Toſcan & </s> <s xml:id="echoid-s9359" xml:space="preserve">du Dorique, il faut <lb/>que les moulures en ſoient unies, afin que tout réponde à la ſim-<lb/>plicité qui convient à ces deux Ordres. </s> <s xml:id="echoid-s9360" xml:space="preserve">Pour le relief des ornemens <lb/>il dépend de la grandeur des moulures, & </s> <s xml:id="echoid-s9361" xml:space="preserve">de l’éloignement d’où <lb/>elles ſeront vûës, prenant garde que ceux des profils du dedans de <lb/>l’édifice ayent moins de relief que ceux du dehors; </s> <s xml:id="echoid-s9362" xml:space="preserve">il faut auſſi <lb/>remarquer que les ornemens doivent être comme apliqués ſur les <lb/>moulures ſaillantes, ſans qu’elles en diminuent la groſſeur, lorſque <lb/>ces moulures ſont petites comme les Aſtragales ou Baguettes, au lieu <lb/>qu’aux Quarts-de-ronds & </s> <s xml:id="echoid-s9363" xml:space="preserve">aux gros Tores, qui ſont de groſſes moulu-<lb/>res, les ornemens doivent être foüillez en dedans, autrement l’ou-<lb/>vrage ſeroit maſſif & </s> <s xml:id="echoid-s9364" xml:space="preserve">peſant s’ils étoient par deſſus; </s> <s xml:id="echoid-s9365" xml:space="preserve">on fait tout le <lb/>contraire pour les moulures creuſes, comme pour les Cavettes & </s> <s xml:id="echoid-s9366" xml:space="preserve"><lb/>les Scoties, dont les ornemens doivent être comme apliquez ſur le <lb/>nud de leur contour & </s> <s xml:id="echoid-s9367" xml:space="preserve">non pas creuſés dedans, parce qu’ainſi on <lb/>les voit diſtinctement.</s> <s xml:id="echoid-s9368" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9369" xml:space="preserve">Les ornemens en general peuvent ſe diviſer en deux eſpeces: </s> <s xml:id="echoid-s9370" xml:space="preserve">ceux <lb/>de la premiere, que l’on nomme ſignificatifs, ſervent de ſimbole pour <lb/>faire connoître l’Edifice: </s> <s xml:id="echoid-s9371" xml:space="preserve">par exemple, ſi c’eſt un Monument élevé <lb/>à la gloire d’un Heros, il eſt naturel d’y figurer quelques traits de <lb/>ſon Hiſtoire & </s> <s xml:id="echoid-s9372" xml:space="preserve">d’y raporter des marques de ſon Triomphe; </s> <s xml:id="echoid-s9373" xml:space="preserve">ce qui <lb/>ne peut guéres ſe pratiquer que ſur la Friſe, à cauſe que ces ſortes <lb/>de choſes ont beſoin d’un certain eſpace pour être exprimées di-<lb/>ſtinctement.</s> <s xml:id="echoid-s9374" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9375" xml:space="preserve">Les ornemens de la ſeconde eſpece ſont ceux qui ſont indiffe-<lb/>rens & </s> <s xml:id="echoid-s9376" xml:space="preserve">qui s’apliquent ſur les moulures ſans aucune conſequence; <lb/></s> <s xml:id="echoid-s9377" xml:space="preserve">tels ſont les Oves que l’on fait de pluſieurs manieres, les Rays de cœur, <lb/>les Fleurs, les Feuilles, & </s> <s xml:id="echoid-s9378" xml:space="preserve">les Fruits, de diverſes eſpeces, & </s> <s xml:id="echoid-s9379" xml:space="preserve">une infinité <lb/>d’autres choſes qui dépendent du goût & </s> <s xml:id="echoid-s9380" xml:space="preserve">du choix: </s> <s xml:id="echoid-s9381" xml:space="preserve">cependant, ſices <lb/>ornemens ne ſont menagez avec beaucoup de circonſpection, les <lb/>profils en deviennent plûtôt confus & </s> <s xml:id="echoid-s9382" xml:space="preserve">groſſiers que riches & </s> <s xml:id="echoid-s9383" xml:space="preserve">agréa-<lb/>bles; </s> <s xml:id="echoid-s9384" xml:space="preserve">le tout eſt de faire enſorte que le coup d’œil ſoit ſatisfait, & </s> <s xml:id="echoid-s9385" xml:space="preserve"><lb/>qu’on aperçoive ſans étude le deſſein que l’on a eû en vûë, & </s> <s xml:id="echoid-s9386" xml:space="preserve">pour <lb/>tout dire en un mot, il faut que les moins connoiſſeurs trouvent de <lb/>quoi admirer, & </s> <s xml:id="echoid-s9387" xml:space="preserve">ſoient ravis d’un certain étonnement qu’a coûtume <lb/>de produire ce qui eſt effectivement beau. </s> <s xml:id="echoid-s9388" xml:space="preserve">Pour donner quelques <lb/>exemples des ornemens qui ont été mis en uſage avec plus de ſuccès <lb/>aux differentes moulures dont nous venons de parler, on a raporté <pb o="12" file="0450" n="486" rhead="LA SCIENCE DES INGENIEURS,"/> ſur la 38 & </s> <s xml:id="echoid-s9389" xml:space="preserve">la 39<emph style="sub">e</emph> Planches pluſieurs deſſeins auſquels on pourra <lb/> <anchor type="note" xlink:label="note-0450-01a" xlink:href="note-0450-01"/> avoir recours dans l’occaſion.</s> <s xml:id="echoid-s9390" xml:space="preserve"/> </p> <div xml:id="echoid-div412" type="float" level="2" n="2"> <note position="left" xlink:label="note-0450-01" xlink:href="note-0450-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>38 & 39.</note> </div> </div> <div xml:id="echoid-div414" type="section" level="1" n="98"> <head xml:id="echoid-head304" xml:space="preserve">CHAPITRE SECOND.</head> <head xml:id="echoid-head305" style="it" xml:space="preserve">De la connoiſſance des cinq Ordres en general.</head> <p> <s xml:id="echoid-s9391" xml:space="preserve">POUR donner une idée des Ordres aux perſonnes qui ne les <lb/>connoiſſent point, & </s> <s xml:id="echoid-s9392" xml:space="preserve">leur faciliter la maniere de les diſtinguer, <lb/>il ſemble qu’avant toute choſe il faut faire voir en quoi ces Ordres <lb/>different, & </s> <s xml:id="echoid-s9393" xml:space="preserve">à quel ſigne on peut les reconnnître.</s> <s xml:id="echoid-s9394" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9395" xml:space="preserve">Si l’on conſidere la 37, 38, & </s> <s xml:id="echoid-s9396" xml:space="preserve">39<emph style="sub">e</emph> Planche, l’on y verra les cinq <lb/>Ordres raportés de ſuite, & </s> <s xml:id="echoid-s9397" xml:space="preserve">l’on y remarquera que le Toſcan ſe diſ-<lb/> <anchor type="note" xlink:label="note-0450-02a" xlink:href="note-0450-02"/> tingue des autres par ſa ſimplicité, n’étant accompagné d’aucun or-<lb/>nement.</s> <s xml:id="echoid-s9398" xml:space="preserve"/> </p> <div xml:id="echoid-div414" type="float" level="2" n="1"> <note position="left" xlink:label="note-0450-02" xlink:href="note-0450-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>37. 38. <lb/>& 39.</note> </div> <p> <s xml:id="echoid-s9399" xml:space="preserve">Que le Dorique ſe connoit par les Trigliphes qui ſervent à enri-<lb/>chir la Friſe, étant l’Ordre ſeul où cet ornement ſe rencontre.</s> <s xml:id="echoid-s9400" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9401" xml:space="preserve">L’Ionique ſe fait connoître entre les autres par les Volutes qui <lb/>accompagnent le Chapiteau des Colomnes.</s> <s xml:id="echoid-s9402" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9403" xml:space="preserve">Le Corinthien ſe connoit auſſi par ſon Chapiteau, qui eſt orné de <lb/>certaines Feuilles qui imitent celles que l’on nomme d’Acanthe: </s> <s xml:id="echoid-s9404" xml:space="preserve">d’ail-<lb/>leurs comme cet ordre eſt toûjours enrichi de pluſieurs ornemens <lb/>qu’on n’aperçoit point dans les trois précédens, il eſt aiſé de ne <lb/>pas s’y méprendre.</s> <s xml:id="echoid-s9405" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9406" xml:space="preserve">Enfin, on connoîtra le Compoſé, en remarquant que ſon chapi-<lb/>teau participe des deux Ordres précédens, ayant les Volutes de <lb/>l’Ionique & </s> <s xml:id="echoid-s9407" xml:space="preserve">les Feuilles du Corinthien.</s> <s xml:id="echoid-s9408" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9409" xml:space="preserve">Il y a beaucoup de bâtimens, qui, ſans avoir de Colomnes ni même <lb/>de Pilaſtres, ne laiſſent pas de prendre le nom de quelqu’un des <lb/>Ordres, parce qu’il ſuffit qu’ils ayent des parties qui en marquent <lb/>le caractere; </s> <s xml:id="echoid-s9410" xml:space="preserve">& </s> <s xml:id="echoid-s9411" xml:space="preserve">ces parties ſont les Entablemens, les Courron-<lb/>nemens de Façades, les grandes Portes &</s> <s xml:id="echoid-s9412" xml:space="preserve">c. </s> <s xml:id="echoid-s9413" xml:space="preserve">Par exemple, quand on <lb/>voit des Trigliphes dans l’Entablement d’une Façade, on peut dire <lb/>que cette Façade eſt décorée ſelon l’Ordre Dorique, ainſi des autres. <lb/></s> <s xml:id="echoid-s9414" xml:space="preserve">Pour donner une idée moins ſuperficielle des Ordres, j’ajouterai que <lb/>chacun eſt ordinairement compoſé de trois parties, qui ſont le Pié-<lb/>d’eſtal, la Colomne, & </s> <s xml:id="echoid-s9415" xml:space="preserve">l’Entablement, & </s> <s xml:id="echoid-s9416" xml:space="preserve">que chacune de ces parties en <lb/>comprend trois autres: </s> <s xml:id="echoid-s9417" xml:space="preserve">par exemple, celles du pié-d’eſtal ſont la Baze, <lb/>le Dé oule Tronc, & </s> <s xml:id="echoid-s9418" xml:space="preserve">la Corniche; </s> <s xml:id="echoid-s9419" xml:space="preserve">celles de la colomne, ſa Baze, le Fuſt<unsure/> <pb file="0451" n="487"/> <pb file="0451a" n="488"/> <anchor type="figure" xlink:label="fig-0451a-01a" xlink:href="fig-0451a-01"/> <pb file="0452" n="489"/> <pb file="0453" n="490"/> <pb file="0453a" n="491"/> <anchor type="figure" xlink:label="fig-0453a-01a" xlink:href="fig-0453a-01"/> <pb file="0454" n="492"/> <pb file="0455" n="493"/> <pb file="0455a" n="494"/> <anchor type="figure" xlink:label="fig-0455a-01a" xlink:href="fig-0455a-01"/> <pb file="0456" n="495"/> <pb o="13" file="0457" n="496" rhead="LIVRE V. DE LA DE’CORATION."/> oula Tige, & </s> <s xml:id="echoid-s9420" xml:space="preserve">le Chapiteau; </s> <s xml:id="echoid-s9421" xml:space="preserve">& </s> <s xml:id="echoid-s9422" xml:space="preserve">celles de l’Entablement, l’Architrave, la <lb/>Friſe, & </s> <s xml:id="echoid-s9423" xml:space="preserve">la Corniche.</s> <s xml:id="echoid-s9424" xml:space="preserve"/> </p> <div xml:id="echoid-div415" type="float" level="2" n="2"> <figure xlink:label="fig-0451a-01" xlink:href="fig-0451a-01a"> <image file="0451a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0451a-01"/> </figure> <figure xlink:label="fig-0453a-01" xlink:href="fig-0453a-01a"> <image file="0453a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0453a-01"/> </figure> <figure xlink:label="fig-0455a-01" xlink:href="fig-0455a-01a"> <image file="0455a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0455a-01"/> </figure> </div> <p> <s xml:id="echoid-s9425" xml:space="preserve">Comme la hauteur du Piédeſtal & </s> <s xml:id="echoid-s9426" xml:space="preserve">de l’Entablement doit dépen-<lb/>dre de celle de la Colomne, Vignole, pour établir une regle gene-<lb/>rale qui puiſſe s’apliquer indiferemment à tel Ordre que l’on voudra, <lb/>donne pour hauteur au Pié-d’eſtal le tiers de celle de la Colomne, <lb/>& </s> <s xml:id="echoid-s9427" xml:space="preserve">à l’Entablement le quart; </s> <s xml:id="echoid-s9428" xml:space="preserve">ainſi ayant diviſée la hauteur de la Co-<lb/>lomne en 12 parties, il en prend quatre pour le Pié-d’eſtal, & </s> <s xml:id="echoid-s9429" xml:space="preserve">trois <lb/>pour l’Entablement, & </s> <s xml:id="echoid-s9430" xml:space="preserve">de cette régle il tire un moyen fort aiſé pour <lb/>déterminer l’Ordonnance d’une Façade: </s> <s xml:id="echoid-s9431" xml:space="preserve">car, toutes les fois qu’une <lb/>hauteur eſt donnée, on n’a qu’à la diviſer en 19 parties égales, & </s> <s xml:id="echoid-s9432" xml:space="preserve"><lb/>alors les quatre parties d’enbas ſervent pour le pié-d’eſtal, les trois <lb/>de deſſus pour l’Entablement, & </s> <s xml:id="echoid-s9433" xml:space="preserve">les douze d’entre deux pour la hau-<lb/>teur de la Colomne.</s> <s xml:id="echoid-s9434" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9435" xml:space="preserve">Cependant, comme il arrive quelquefois, que dans la décoration <lb/>des Façades, on ne fait point de Piédeſtal aux Colomnes; </s> <s xml:id="echoid-s9436" xml:space="preserve">dans ce <lb/>cas, Vignole diviſe la hauteur donnée en 5 parties égales, dont 4 <lb/>ſervent pour la hauteur de la Colomne, & </s> <s xml:id="echoid-s9437" xml:space="preserve">la cinquiéme partie dé-<lb/>termine celle de l’Entablement, qui par ce moyen ſera encore le <lb/>quart de la hauteur de la Colomne.</s> <s xml:id="echoid-s9438" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9439" xml:space="preserve">Comme, dans tous les Ordres, la proportion des petites parties <lb/>doit dépendre de celle des plus grandes, tous les Architectes, tant <lb/>anciens que modernes, ont pris pour meſure commune le demi-<lb/>diamêtre de la Colomne qu’ils ont apellé Module; </s> <s xml:id="echoid-s9440" xml:space="preserve">deſorte que quand <lb/>on dit qu’une certaine partie d’Architecture a, par exemple, pour <lb/>hauteur 5 modules, on doit entendre que cette hauteur eſt égale <lb/>à 5 demi diamêtres de la Colomne qui eſt employée dans l’Ordre <lb/>dont il s’agit: </s> <s xml:id="echoid-s9441" xml:space="preserve">cependant, comme pour rendre les Colomnes plus a-<lb/>gréables à la vûë, on leur a donné moins de groſſeur vers les ex-<lb/>trêmités que dans le milieu; </s> <s xml:id="echoid-s9442" xml:space="preserve">ce qui fait que n’étant point cilindri-<lb/>ques, elles peuvent avoir pluſieurs diamêtres, il eſt bon de ſavoir <lb/>pour ne pas s’y méprendre, que le demi-diamêtre qui ſert de mo-<lb/>dule, eſt celui du cercle qui répond à la Baſe de la Colomne.</s> <s xml:id="echoid-s9443" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9444" xml:space="preserve">Les cinq Ordres augmentant de ſuite en beauté & </s> <s xml:id="echoid-s9445" xml:space="preserve">en ornement, <lb/>on les a fait auſſi monter par degré en legereté & </s> <s xml:id="echoid-s9446" xml:space="preserve">en délicateſſe: </s> <s xml:id="echoid-s9447" xml:space="preserve">par <lb/>exemple, les colomnes Doriques ont moins de groſſeur par raport à <lb/>leur hauteur, que les Toſcanes; </s> <s xml:id="echoid-s9448" xml:space="preserve">& </s> <s xml:id="echoid-s9449" xml:space="preserve">les Ioniques moins de groſſeur <lb/>à proportion de leur hauteur, que les Doriques; </s> <s xml:id="echoid-s9450" xml:space="preserve">ainſi des autres. <lb/></s> <s xml:id="echoid-s9451" xml:space="preserve">C’eſt pourquoi Vignole donne aux colomnes Toſcanes 7 de leurs <lb/>diamêtres, ou 14 modules; </s> <s xml:id="echoid-s9452" xml:space="preserve">aux Doriques, 8 de leurs diamêtres, ou <lb/>16 modules; </s> <s xml:id="echoid-s9453" xml:space="preserve">aux Ioniques, 9 de leurs diamêtres, ou 18 modules;</s> <s xml:id="echoid-s9454" xml:space="preserve"> <pb o="14" file="0458" n="497" rhead="LA SCIENCE DES INGENIEURS,"/> aux Corinthienes & </s> <s xml:id="echoid-s9455" xml:space="preserve">aux Compoſites, 10 de leurs diamêtres ou 20 mo-<lb/>dules, donnant la même élevation à ces deux Ordres, quoiqu’il y ait <lb/>des Auteurs qui en donnent davantage au Compoſite. </s> <s xml:id="echoid-s9456" xml:space="preserve">Prevenu de ce <lb/>que je viens de dire, quand on a trouvé de quelle hauteur doit être la <lb/>Colomne par raport à la Façade où elle doit être placée, en ſuivant la <lb/>régle de Vignole, il eſt bien aiſé d’en avoir le diamêtre, & </s> <s xml:id="echoid-s9457" xml:space="preserve">par conſe-<lb/>quent le module, puiſqu’il n’y a qu’à diviſer la hauteur de la Colomne <lb/>en autant de parties égales, qu’elle doit avoir de diamêtre: </s> <s xml:id="echoid-s9458" xml:space="preserve">& </s> <s xml:id="echoid-s9459" xml:space="preserve">alors <lb/>une de ces parties ſera le diamêtre qu’on cherche, dont la moitié <lb/>pourra ſervir de module; </s> <s xml:id="echoid-s9460" xml:space="preserve">car l’on ſent bien que chaque Ordre a ſon <lb/>module particulier, qui eſt plus ou moins grand, ſelon que l’Ordre <lb/>dont il s’agit eſt maſſif ou leger, & </s> <s xml:id="echoid-s9461" xml:space="preserve">qu’il n’en eſt point de cette me-<lb/>ſure comme dupied ou du pouce ordinaire, qui reſtent toûjours de <lb/>même. </s> <s xml:id="echoid-s9462" xml:space="preserve">Or, pour rendre ceci plus intelligible, ſupoſons qu’il ſoit queſ-<lb/>tion de decorer une Façade ſelon l’Ordre Dorique, il faut en meſu-<lb/>rer la hauteur depuis le rez-de-Chauſſée, juſqu’à l’endroit où doit <lb/>ſe terminer le ſommet de la Corniche de l’Entablement & </s> <s xml:id="echoid-s9463" xml:space="preserve">diviſer <lb/>cette hauteur en 19 parties, dont il en faut prendre 12 pour la co-<lb/>lomne pour tel Ordre que ce ſoit; </s> <s xml:id="echoid-s9464" xml:space="preserve">& </s> <s xml:id="echoid-s9465" xml:space="preserve">ces 12 parties n’étant plus con-<lb/>ſiderées que comme une ſeule grandeur, il faut la diviſer en 8 par-<lb/>ties égales, l’une deſquelles ſera le diamêtre de la Colomne, par con-<lb/>ſequent la moitié de ce diamêtre ſera le module pour régler les pro-<lb/>portions de l’Ordre Dorique, relativement à la Façade que l’on veut <lb/>décorer: </s> <s xml:id="echoid-s9466" xml:space="preserve">or comme on aura connû en pieds & </s> <s xml:id="echoid-s9467" xml:space="preserve">en pouces la hauteur <lb/>de cette Façade, on pourra auſſi ſi l’on veut raporter la grandeur du <lb/>module aux meſures ordinaires, & </s> <s xml:id="echoid-s9468" xml:space="preserve">fçavoir par conſequent combien <lb/>il contient de pouces, quoiqu’à le bien prendre cela ſoit aſſés inutile, <lb/>puiſque, comme je viens de le dire, cette meſure eſt particuliere <lb/>aux Ordres, & </s> <s xml:id="echoid-s9469" xml:space="preserve">n’a rien de commun avec la toiſe.</s> <s xml:id="echoid-s9470" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9471" xml:space="preserve">Toutes les meſures en uſage dans la ſocieté, ayant été diviſées <lb/>en pluſieurs parties, pour les raiſons que perſonne n’ignore, les Ar-<lb/>chitectes ont auſſi diviſé leurs modules en un nombre de parties <lb/>égales, les unes plus, les autres moins, ſelon qu’ils en ont crû ti-<lb/>rer plus de commodité, quand ils ont été obligés de déterminer la <lb/>grandeur des moulures & </s> <s xml:id="echoid-s9472" xml:space="preserve">des autres petites parties, afin qu’elles <lb/>euſſent entre elles certaines proportions qui leur convinſſent par <lb/>raport à l’harmonie qui devoit regner dans le tout: </s> <s xml:id="echoid-s9473" xml:space="preserve">& </s> <s xml:id="echoid-s9474" xml:space="preserve">Vignole a <lb/>cela d’avantageux au-deſſus des autres, c’eſt que les parties de ſon <lb/>module ne ſont point ſuſceptibles de fractions embaraſſantes; </s> <s xml:id="echoid-s9475" xml:space="preserve">l’on <lb/>ſaura donc, que pour l’Ordre Toſcan & </s> <s xml:id="echoid-s9476" xml:space="preserve">le Dorique, il diviſe le mo-<lb/>dule en 12 parties égales: </s> <s xml:id="echoid-s9477" xml:space="preserve">mais, comme dans les trois autres Ordres, <pb o="15" file="0459" n="498" rhead="LIVRE V. DE LA DE’CORATION."/> c’eſt-à-dire l’Ionique, le Corinthien, & </s> <s xml:id="echoid-s9478" xml:space="preserve">le Compoſite, il ſe ren-<lb/>contre des moulures encore plus petites que dans les precedens, il <lb/>a diviſé le module de ces trois Ordres en 18 parties égales, afin <lb/>d’éviter les fractions qui ſe ſeroient rencontrées, s’il ne l’avoit été <lb/>qu’en 12 parties.</s> <s xml:id="echoid-s9479" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9480" xml:space="preserve">Comme ce que je viens d’expliquer dans ce Chapitre ſuffit pour <lb/>être prévenu de ce qu’il faut ſavoir afin d’entendre clairement ce <lb/>que l’on verra dans la ſuite, je paſſe à la compoſition des Ordres, <lb/>en commençant par le Toſcan.</s> <s xml:id="echoid-s9481" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div417" type="section" level="1" n="99"> <head xml:id="echoid-head306" xml:space="preserve">CHAPITRE TROISIE’ME.</head> <head xml:id="echoid-head307" style="it" xml:space="preserve">De l’Ordre Toſcan.</head> <p> <s xml:id="echoid-s9482" xml:space="preserve">DANS l’Ordre Toſcan le fuſt de la colomne a pour hauteur <lb/>6 de ſes diamêtres, c’eſt-à-dire 12 modules, & </s> <s xml:id="echoid-s9483" xml:space="preserve">ſa baſe & </s> <s xml:id="echoid-s9484" xml:space="preserve">ſon <lb/>chapiteau chacun un, ce qui fait en tout 14 modules comme nous <lb/>l’avons dit dans le Chapitre précédent; </s> <s xml:id="echoid-s9485" xml:space="preserve">dont le tiers, qui eſt de 4 <lb/>modules 8 parties, eſt pour la hauteur du Piédeſtal, & </s> <s xml:id="echoid-s9486" xml:space="preserve">le quart, qui <lb/>fait 8 modules 6 parties, pour celle de l’entablement; </s> <s xml:id="echoid-s9487" xml:space="preserve">ainſi toute <lb/>la hauteur de la Façade, ou ſi l’on veut de l’Ordonnance, ſe trouve <lb/>de 22 modules 2 parties, car il faut ſe rappeller que le module dans <lb/>cet Ordre doit être diviſé en 12 parties égales, & </s> <s xml:id="echoid-s9488" xml:space="preserve">que ce ſont ces <lb/>parties qui vont ſervir à déterminer la proportion des moulures.</s> <s xml:id="echoid-s9489" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9490" xml:space="preserve">Comme nous allons donner les dimenſions dont chaque Ordre eſt <lb/>compoſé, & </s> <s xml:id="echoid-s9491" xml:space="preserve">que les mêmes dimenſions ſe trouvent exactement cot-<lb/>tées ſur les deſſeins, l’on pourra à l’aide du diſcours connoître plus <lb/>diſtinctement qu’on ne l’a fait dans ce qui précede, la ſituation des <lb/>moulures, leurs figures, & </s> <s xml:id="echoid-s9492" xml:space="preserve">leurs noms; </s> <s xml:id="echoid-s9493" xml:space="preserve">puiſque chaque chiffre, dont <lb/>on va faire mention dans l’explication, pourra ſervir en même tems <lb/>à déſigner celle dont on parle: </s> <s xml:id="echoid-s9494" xml:space="preserve">par exemple, quand on dira que la <lb/>Plinthe de la baſe du Piédeſtal Toſcan eſt de 5 parties, il fuſſira <lb/>de jetter les yeux ſur cette baſe, pour voir que la moulure qui ré-<lb/>pond au chiffre 5 eſt nommée Plinthe; </s> <s xml:id="echoid-s9495" xml:space="preserve">ainſi des autres qui ſe ſui-<lb/>vront immediatement, ce qui contribuera fort à ſe rendre les ter-<lb/>mes familiers.</s> <s xml:id="echoid-s9496" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div418" type="section" level="1" n="100"> <head xml:id="echoid-head308" style="it" xml:space="preserve">Piédeſtal Toſcan.</head> <p> <s xml:id="echoid-s9497" xml:space="preserve">L’on donne un demi-module ou 6 parties à la hauteur de la baſe <lb/> <anchor type="note" xlink:label="note-0459-01a" xlink:href="note-0459-01"/> du Piédeſtal dont il y en a 5 pour la Plinthe, & </s> <s xml:id="echoid-s9498" xml:space="preserve">une pour le re- <pb o="16" file="0460" n="499" rhead="LA SCIENCE DES INGENIEURS,"/> glet: </s> <s xml:id="echoid-s9499" xml:space="preserve">la ſaillie de la Plinthe eſt de 4 parties, & </s> <s xml:id="echoid-s9500" xml:space="preserve">celle du reglet de 2. <lb/></s> <s xml:id="echoid-s9501" xml:space="preserve">Quant à la largeur du Dé ou du Tronc, elle eſt de 2 modules 9 <lb/>parties, & </s> <s xml:id="echoid-s9502" xml:space="preserve">ſa hauteur de 3 modules 8 parties.</s> <s xml:id="echoid-s9503" xml:space="preserve"/> </p> <div xml:id="echoid-div418" type="float" level="2" n="1"> <note position="right" xlink:label="note-0459-01" xlink:href="note-0459-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>40. <lb/><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s9504" xml:space="preserve">La hauteur de la corniche eſt égale à celle de ſa baſe, c’eſt-à-<lb/>dire qu’elle eſt de 6 parties, deſquelles on en donne 4 au Talon, & </s> <s xml:id="echoid-s9505" xml:space="preserve"><lb/>deux à la Bandelette ou Reglet: </s> <s xml:id="echoid-s9506" xml:space="preserve">toute la ſaillie eſt de 4 parties, dont <lb/>il y en a 3 & </s> <s xml:id="echoid-s9507" xml:space="preserve">demi pour le Talon, 1 & </s> <s xml:id="echoid-s9508" xml:space="preserve">demi pour le Reglet qui eſt <lb/>au-deſſus.</s> <s xml:id="echoid-s9509" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div420" type="section" level="1" n="101"> <head xml:id="echoid-head309" style="it" xml:space="preserve">Colomne Toſcane.</head> <p> <s xml:id="echoid-s9510" xml:space="preserve">Cette Colomne à 2 modules par le bas & </s> <s xml:id="echoid-s9511" xml:space="preserve">un module 7 parties par <lb/>le haut, parce qu’elle va en diminuant depuis en bas juſqu’en haut <lb/>& </s> <s xml:id="echoid-s9512" xml:space="preserve">que cette diminution eſt de 2 parties & </s> <s xml:id="echoid-s9513" xml:space="preserve">demi de chaque côté.</s> <s xml:id="echoid-s9514" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9515" xml:space="preserve">La baſe de la Colomne a 12 parties, dont il y en a 6 pour la <lb/>Plinthe, 5 pour le Tore, & </s> <s xml:id="echoid-s9516" xml:space="preserve">une pour l’Anneau: </s> <s xml:id="echoid-s9517" xml:space="preserve">la ſaillie de la Plinthe <lb/>& </s> <s xml:id="echoid-s9518" xml:space="preserve">du Tore eſt de 4 parties & </s> <s xml:id="echoid-s9519" xml:space="preserve">demi de chaque côté, celle de l’An-<lb/>neau n’eſt que d’une partie & </s> <s xml:id="echoid-s9520" xml:space="preserve">demi; </s> <s xml:id="echoid-s9521" xml:space="preserve">à l’égard de l’Anneau & </s> <s xml:id="echoid-s9522" xml:space="preserve">de l’Aſ-<lb/>tragale qui ſont au ſommet du fuſt de la Colomne, la hauteur du <lb/>premier eſt d’une demi partie, celle du ſecond, d’une partie, la <lb/>ſaillie de ce dernier eſt d’une partie & </s> <s xml:id="echoid-s9523" xml:space="preserve">demi de chaque côté.</s> <s xml:id="echoid-s9524" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9525" xml:space="preserve">La hauteur du Chapiteau étant de 12 parties comme celle de la <lb/>Baſe, le Gorgerin en a 4, l’Anneau une, l’Ove 3, l’Abaque 3, & </s> <s xml:id="echoid-s9526" xml:space="preserve">le <lb/> <anchor type="note" xlink:label="note-0460-01a" xlink:href="note-0460-01"/> Reglet une; </s> <s xml:id="echoid-s9527" xml:space="preserve">la largeur du Gorgerin eſt d’un module 7 parties, & </s> <s xml:id="echoid-s9528" xml:space="preserve"><lb/>par conſequent n’a point de ſaillie au-deſſus du ſommet de la Colom-<lb/>ne, toute la largeur de l’Abaque eſt de 2 modules 5 parties, ainſi ſa <lb/>ſaillie eſt de 5 parties de chaque côté en y comprenant celle de ſon <lb/>Reglet qui eſt au-deſſus, la ſaillie de l’Anneau eſt d’une partie de <lb/>chaque côté.</s> <s xml:id="echoid-s9529" xml:space="preserve"/> </p> <div xml:id="echoid-div420" type="float" level="2" n="1"> <note position="left" xlink:label="note-0460-01" xlink:href="note-0460-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>41. <lb/><emph style="sc">Fig</emph>. 1.</note> </div> </div> <div xml:id="echoid-div422" type="section" level="1" n="102"> <head xml:id="echoid-head310" style="it" xml:space="preserve">Entablement Toſcan.</head> <p> <s xml:id="echoid-s9530" xml:space="preserve">La hauteur de l’Entablement étant comme on l’a dit de 3 mo-<lb/>dules & </s> <s xml:id="echoid-s9531" xml:space="preserve">demi, ou de 42 parties, l’Architrave doit en avoir 12 en <lb/>y comprenant la hauteur du Reglet qui en a 2, la Friſe 14: </s> <s xml:id="echoid-s9532" xml:space="preserve">la Cor-<lb/>niche qui comprend le Talon, le Larmier, & </s> <s xml:id="echoid-s9533" xml:space="preserve">l’Ove, avec les Filets qui <lb/>les accompagnent en a 16 parties, dont le Talon en a 4, le Filet au-<lb/>deſſus une demie, le Larmier 6, le Filet au-deſſus une demie, l’Aſ-<lb/>tragale qui eſt au-deſſous de l’Ove une, & </s> <s xml:id="echoid-s9534" xml:space="preserve">l’Ove 4; </s> <s xml:id="echoid-s9535" xml:space="preserve">la Friſe & </s> <s xml:id="echoid-s9536" xml:space="preserve">l’Ar-<lb/>chitrave n’ont point de ſaillies, l’un & </s> <s xml:id="echoid-s9537" xml:space="preserve">l’autre devant répondre au <lb/>vif du haut de la Colomne: </s> <s xml:id="echoid-s9538" xml:space="preserve">toute la ſaillie de la Corniche eſt de 18 <lb/>parties, chaque membre particulier a autant de ſaillie que de hauteur, <lb/>excepté le Larmier dont la ſaillie eſt de 9 parties, (en y comprenant <pb o="17" file="0461" n="500" rhead="LIVRE V. DE LA DE’CORATION."/> le Filet qui eſt au-deſſous, quoique ſa hauteur ne ſoit que de 6: </s> <s xml:id="echoid-s9539" xml:space="preserve">& </s> <s xml:id="echoid-s9540" xml:space="preserve"><lb/>pour juger de l’effet que font toutes ces ſaillies, il ſuffira de conſi-<lb/>derer le deſſein, où les proportions de toutes les parties ſont exacte-<lb/>ment marquées. </s> <s xml:id="echoid-s9541" xml:space="preserve">L’on creuſe ordinairement dans le Larmier un Ca-<lb/>nal que les Ouvriers apellent Mouchette pendante, ce Canal ſe prati-<lb/>que, afin de rendre l’ouvrage plus leger, & </s> <s xml:id="echoid-s9542" xml:space="preserve">pour empêcher que l’eau <lb/>n’aille couler ſur la Friſe.</s> <s xml:id="echoid-s9543" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9544" xml:space="preserve">Quand on employe l’Ordre Toſcan aux Portes des Villes ou à <lb/>celles de quelques Edifices militaires, on peut, pour leur donner <lb/>plus de majeſté, revêtir les Colomnes de Boſſages ou de Ceintures <lb/>& </s> <s xml:id="echoid-s9545" xml:space="preserve">de Bandes, pourvû qu’elles ſoient ruſtiques & </s> <s xml:id="echoid-s9546" xml:space="preserve">ſans ſculpture: </s> <s xml:id="echoid-s9547" xml:space="preserve">ce <lb/>ruſtique ſe fait pointillé également, ou en tortillis comme les pierres <lb/>mangées & </s> <s xml:id="echoid-s9548" xml:space="preserve">moulinées par la Lune, ce qui peut être apellé Ruſtique <lb/>vermicule; </s> <s xml:id="echoid-s9549" xml:space="preserve">cependant, comme ces Boſſages augmentent le module <lb/>de la Colomne, & </s> <s xml:id="echoid-s9550" xml:space="preserve">la rend plus courte qu’elle ne ſeroit ſi elle étoit <lb/>toute unie, il eſt à propos de lui donner pour hauteur un peu plus <lb/>des 7 diamêtres.</s> <s xml:id="echoid-s9551" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9552" xml:space="preserve">Si l’on vouloit ſe ſervir de l’Ordre Toſcan ſans Piédeſtal, il fau-<lb/>droit diviſer la hauteur donnée en 5 parties égales, dont il y en aura <lb/>4 pour la hauteur de la Colomne y compris ſa Baſe & </s> <s xml:id="echoid-s9553" xml:space="preserve">ſon Chapiteau, <lb/>& </s> <s xml:id="echoid-s9554" xml:space="preserve">pour la hauteur de l’entablement, une. </s> <s xml:id="echoid-s9555" xml:space="preserve">Or ſi l’on diviſe enſuite la <lb/>hauteur de la Colomne, c’eſt-à-dire les quatre cinquiémes de la hau-<lb/>teur qu’on veut donner à l’Ordonnance en 14 parties égales, une <lb/>de ces parties ſervira de module: </s> <s xml:id="echoid-s9556" xml:space="preserve">ainſi le Fuſt de la Colomne aura <lb/>comme cy-devant 12 modules, la Baſe & </s> <s xml:id="echoid-s9557" xml:space="preserve">le Chapiteau chacun un; <lb/></s> <s xml:id="echoid-s9558" xml:space="preserve">& </s> <s xml:id="echoid-s9559" xml:space="preserve">comme le quart de 14 eſt 3 & </s> <s xml:id="echoid-s9560" xml:space="preserve">demi, il s’enſuit que l’Entable-<lb/>ment aura encore 3 modules & </s> <s xml:id="echoid-s9561" xml:space="preserve">demi de hauteur, & </s> <s xml:id="echoid-s9562" xml:space="preserve">toute l’Or-<lb/>donnance 17 & </s> <s xml:id="echoid-s9563" xml:space="preserve">demi.</s> <s xml:id="echoid-s9564" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9565" xml:space="preserve">Mr. </s> <s xml:id="echoid-s9566" xml:space="preserve">de Chambray, en parlant de l’Ordre Toſcan, dit que ſa Colom-<lb/>ne ſans aucun Architrave eſt la ſeule piece qui mérite d’être miſe en <lb/>œuvre, & </s> <s xml:id="echoid-s9567" xml:space="preserve">qui peut rendre cet Ordre recommandable: </s> <s xml:id="echoid-s9568" xml:space="preserve">il fait enſuite <lb/>la deſcription de la Colomne Trajane, dont il remarque l’excellence, <lb/>& </s> <s xml:id="echoid-s9569" xml:space="preserve">qu’il croit avoir ſervi de regle à la Colomne Antonine, & </s> <s xml:id="echoid-s9570" xml:space="preserve">à une <lb/>autre qui fut élevée dans Conſtantinople à l’honneur de l’Empereur <lb/>Theodoſe. </s> <s xml:id="echoid-s9571" xml:space="preserve">Pour cette derniere, elle eſt des plus belles, non-ſeule-<lb/>ment parce qu’elle eſt bien proportionnée, mais par l’ouvrage en <lb/>bas relief dont elle eſt entourée depuis le bas juſqu’en haut, où <lb/>l’on voit la deſcription du triomphe de cet Empereur après avoir <lb/>vaincu les Scites. </s> <s xml:id="echoid-s9572" xml:space="preserve">J’en ai une Eſtampe, qui a bien 25 pieds de lon-<lb/>gueur ſur 2 de hauteur, gravée ſur le deſſein d’un R. </s> <s xml:id="echoid-s9573" xml:space="preserve">P. </s> <s xml:id="echoid-s9574" xml:space="preserve">Jeſuite qui <lb/>l’a fait à Conſtantinople d’après l’original. </s> <s xml:id="echoid-s9575" xml:space="preserve">Cependant, ſelon Felibien, <pb o="18" file="0462" n="501" rhead="LA SCIENCE DES INGENIEURS,"/> il y a aparence que la Colomne Trajane n’eſt pas la premiere que <lb/>l’on a dreſſée à l’honneur de grands hommes; </s> <s xml:id="echoid-s9576" xml:space="preserve">puiſqu’il n’y a pas long-<lb/>tems que l’on voyoit à Rome une petite Colomne Toſcane, ſur la-<lb/>quelle étoit la figure d’un Corbeau avec ce mot au-deſſous (Corvin), <lb/>qui marque ſelon toute aparence que cette Colomne fut élevée à <lb/>Valerius Maximus, après l’action qu’il fit à la vûë de l’Armée des <lb/>Gaulois & </s> <s xml:id="echoid-s9577" xml:space="preserve">de celle des Romains, où il accepta le deffi d’un géant <lb/>qui ſortit de l’Armée ennemie, qu’il combatit & </s> <s xml:id="echoid-s9578" xml:space="preserve">vainquit avec le <lb/>ſecours d’un Corbeau qui vint ſe placer ſur ſa tête, ce qui lui fit <lb/>prendre enſuite le ſurnom de Corvinius: </s> <s xml:id="echoid-s9579" xml:space="preserve">& </s> <s xml:id="echoid-s9580" xml:space="preserve">comme, ſuivant l’Hi-<lb/>ſtoire Romaine nouvellement miſe au jour par les R. </s> <s xml:id="echoid-s9581" xml:space="preserve">R. </s> <s xml:id="echoid-s9582" xml:space="preserve">P. </s> <s xml:id="echoid-s9583" xml:space="preserve">P. </s> <s xml:id="echoid-s9584" xml:space="preserve">Ca-<lb/> <anchor type="note" xlink:label="note-0462-01a" xlink:href="note-0462-01"/> trou & </s> <s xml:id="echoid-s9585" xml:space="preserve">Roüillé, de la Compagnie de Jeſus, cette action mémora-<lb/>ble eſt arrivée l’an 404. </s> <s xml:id="echoid-s9586" xml:space="preserve">de la Fondation de Rome, l’on voit com-<lb/>bien cette Colomne eſt plus ancienne que la Trajane.</s> <s xml:id="echoid-s9587" xml:space="preserve"/> </p> <div xml:id="echoid-div422" type="float" level="2" n="1"> <note position="left" xlink:label="note-0462-01" xlink:href="note-0462-01a" xml:space="preserve">Voyez <lb/>l’Hiſtorie <lb/>citée To. <lb/>4. p. 232.</note> </div> </div> <div xml:id="echoid-div424" type="section" level="1" n="103"> <head xml:id="echoid-head311" xml:space="preserve">CHAPITRE QUATRIE’ME.</head> <head xml:id="echoid-head312" style="it" xml:space="preserve">De l’Ordre Dorique.</head> <p> <s xml:id="echoid-s9588" xml:space="preserve">LA hauteur de toute la Colomne de cet Ordre, y compris la <lb/>Baſe & </s> <s xml:id="echoid-s9589" xml:space="preserve">le Chapiteau, ſelon Vignole, eſt de 16 modules, dont <lb/>il y en a un tiers, c’eſt-à-dire 5 modules 4 parties, pour le Piédeſtal, <lb/>un quart pour la hauteur de l’entablement qui ſera par conſéquent <lb/>de 4 modules, & </s> <s xml:id="echoid-s9590" xml:space="preserve">le module eſt encore diviſé en 12 parties comme <lb/>pour l’Ordre Toſcan.</s> <s xml:id="echoid-s9591" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div425" type="section" level="1" n="104"> <head xml:id="echoid-head313" style="it" xml:space="preserve">Piédeſtal Dorique.</head> <p> <s xml:id="echoid-s9592" xml:space="preserve">La hauteur du Piédeſtal étant de 5 modules 4 parties, on en <lb/> <anchor type="note" xlink:label="note-0462-02a" xlink:href="note-0462-02"/> donne 10 à la Baſe & </s> <s xml:id="echoid-s9593" xml:space="preserve">6 à la Corniche; </s> <s xml:id="echoid-s9594" xml:space="preserve">ainſi le Dé ou Tronc ſe trou-<lb/>ve de 4 modules de hauteur.</s> <s xml:id="echoid-s9595" xml:space="preserve"/> </p> <div xml:id="echoid-div425" type="float" level="2" n="1"> <note position="left" xlink:label="note-0462-02" xlink:href="note-0462-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>40.</note> </div> <note position="left" xml:space="preserve"><emph style="sc">Fig</emph>. 2.</note> <p> <s xml:id="echoid-s9596" xml:space="preserve">Des 10 parties de la Baſe on en donne 4 au Socle, deux & </s> <s xml:id="echoid-s9597" xml:space="preserve">de-<lb/>mi à la Plinthe, 2 au Talon renverſé, une à l’Aſtragale, & </s> <s xml:id="echoid-s9598" xml:space="preserve">une & </s> <s xml:id="echoid-s9599" xml:space="preserve"><lb/>demi au Filet.</s> <s xml:id="echoid-s9600" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9601" xml:space="preserve">La ſaillie du Socle eſt de 4 parties & </s> <s xml:id="echoid-s9602" xml:space="preserve">demi, celle de la Plinthe <lb/>de 4, celle du Talon renverſé de 3 & </s> <s xml:id="echoid-s9603" xml:space="preserve">demi, celle de l’Aſtragale <lb/>de 2, & </s> <s xml:id="echoid-s9604" xml:space="preserve">celle du Filet d’une, & </s> <s xml:id="echoid-s9605" xml:space="preserve">la largeur du Dé ſe trouve de 2 <lb/>modules 10 parties.</s> <s xml:id="echoid-s9606" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9607" xml:space="preserve">Des 6 parties qui compoſent la hauteur de la Corniche, on en <lb/>donne 1 & </s> <s xml:id="echoid-s9608" xml:space="preserve">demi au Talon, 2 & </s> <s xml:id="echoid-s9609" xml:space="preserve">demi à la Goûtiere, une demi au <lb/>Filet, une à l’Ove, & </s> <s xml:id="echoid-s9610" xml:space="preserve">une demi au Reglet.</s> <s xml:id="echoid-s9611" xml:space="preserve"/> </p> <pb o="19" file="0463" n="502" rhead="LIVRE V. DE LA DE’CORATION."/> <p> <s xml:id="echoid-s9612" xml:space="preserve">La ſaillie de la Corniche eſt égale à ſa hauteur; </s> <s xml:id="echoid-s9613" xml:space="preserve">c’eſt-à-dire qu’elle <lb/>eſt de 6 parties, dont il y en a 1 demi pour celle du Talon, 4 pour <lb/>celle de la Goûtiere, & </s> <s xml:id="echoid-s9614" xml:space="preserve">6 pour celle du Reglet & </s> <s xml:id="echoid-s9615" xml:space="preserve">de l’Ove qui eſt <lb/>au-deſſous.</s> <s xml:id="echoid-s9616" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div427" type="section" level="1" n="105"> <head xml:id="echoid-head314" style="it" xml:space="preserve">Colomne Dorique.</head> <p> <s xml:id="echoid-s9617" xml:space="preserve">De 16 modules que l’on donne à la hauteur de la Colomne, il <lb/>y en a une pour la Baſe & </s> <s xml:id="echoid-s9618" xml:space="preserve">une autre pour le Chapiteau: </s> <s xml:id="echoid-s9619" xml:space="preserve">ainſi il <lb/>reſte 14 modules pour le Fuſt, & </s> <s xml:id="echoid-s9620" xml:space="preserve">la diminution de cette Colomne <lb/>par le haut eſt de 4 parties, deux d’un côté, & </s> <s xml:id="echoid-s9621" xml:space="preserve">deux de l’autre; </s> <s xml:id="echoid-s9622" xml:space="preserve">par <lb/>conſequent, le vif de cette Colomne eſt d’un module 8 parties.</s> <s xml:id="echoid-s9623" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9624" xml:space="preserve">La Baſe étant de 12 parties, on en donne 6 à la Plinthe, 4 au Tore, <lb/>une à l’Aſtragale, & </s> <s xml:id="echoid-s9625" xml:space="preserve">une au Reglet ou Anneau: </s> <s xml:id="echoid-s9626" xml:space="preserve">ſur quoi il faut remar-<lb/>quer, qu’il n’y a que dans l’Ordre Toſcan & </s> <s xml:id="echoid-s9627" xml:space="preserve">le Dorique, où le Filet <lb/>fait partie de la Baſe; </s> <s xml:id="echoid-s9628" xml:space="preserve">car, dans les trois Ordres ſuivans il apartient <lb/>au Fuſt de la Colomne.</s> <s xml:id="echoid-s9629" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9630" xml:space="preserve">La largeur de la Plinthe auſſi-bien que celle du Tore eſt de 2 mo-<lb/>dules 10 parties, parce que ces deux membres n’ont point de ſaillie <lb/>au-deſſus du Dé du Piédeſtal; </s> <s xml:id="echoid-s9631" xml:space="preserve">mais, celle de l’Aſtragale eſt de 2 par-<lb/>ties 3 quarts au-deſſus de la Colomne, & </s> <s xml:id="echoid-s9632" xml:space="preserve">celle du Filet 2.</s> <s xml:id="echoid-s9633" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9634" xml:space="preserve">Ayant compris dans la hauteur du Tronc de la Colomne, l’Aſtra-<lb/> <anchor type="note" xlink:label="note-0463-01a" xlink:href="note-0463-01"/> gale & </s> <s xml:id="echoid-s9635" xml:space="preserve">le Filet qui ſe trouvent au ſommet, on doit dans cet Ordre <lb/> <anchor type="note" xlink:label="note-0463-02a" xlink:href="note-0463-02"/> auſſi-bien qu’au Toſcan ſéparer ces deux moulures du Chapiteau; <lb/></s> <s xml:id="echoid-s9636" xml:space="preserve">ainſi il ſuffira de dire que le Filet eſt d’une & </s> <s xml:id="echoid-s9637" xml:space="preserve">demi partie, & </s> <s xml:id="echoid-s9638" xml:space="preserve">l’Aſtra-<lb/>gale d’une, & </s> <s xml:id="echoid-s9639" xml:space="preserve">que la ſaillie de l’Aſtragale eſt de 2 parties, & </s> <s xml:id="echoid-s9640" xml:space="preserve">celle <lb/>du Filet d’une & </s> <s xml:id="echoid-s9641" xml:space="preserve">demi.</s> <s xml:id="echoid-s9642" xml:space="preserve"/> </p> <div xml:id="echoid-div427" type="float" level="2" n="1"> <note position="right" xlink:label="note-0463-01" xlink:href="note-0463-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>41.</note> <note position="right" xlink:label="note-0463-02" xlink:href="note-0463-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 2.</note> </div> <p> <s xml:id="echoid-s9643" xml:space="preserve">La Colomne commence à diminuer au tiers de ſa hauteur, ou <lb/>même dès le pied, auquel cas on lui donne 2 modules & </s> <s xml:id="echoid-s9644" xml:space="preserve">2 parties <lb/>pour le diamêtre qui répond au tiers de la hauteur, afin de la faire <lb/>renfler d’une partie de chaque côté: </s> <s xml:id="echoid-s9645" xml:space="preserve">nous parlerons dans la ſuite de <lb/>la maniere que ſe trace la diminution & </s> <s xml:id="echoid-s9646" xml:space="preserve">le renflement.</s> <s xml:id="echoid-s9647" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9648" xml:space="preserve">De 12 parties que le Chapiteau a de hauteur, on en donne 4 au <lb/>Gorgerin & </s> <s xml:id="echoid-s9649" xml:space="preserve">une demi à chacun des trois Reglets ou Anneaux qui <lb/>ſont immédiatement après, 2 & </s> <s xml:id="echoid-s9650" xml:space="preserve">demi à l’Ove qui eſt au-deſſus, 2 <lb/>& </s> <s xml:id="echoid-s9651" xml:space="preserve">demi à la Goûtiere de l’Abaque, une au Talon, & </s> <s xml:id="echoid-s9652" xml:space="preserve">une demi au <lb/>Reglet.</s> <s xml:id="echoid-s9653" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9654" xml:space="preserve">La ſaillie du Reglet de l’Abaque a 5 parties & </s> <s xml:id="echoid-s9655" xml:space="preserve">demi de chaque <lb/>côté, ainſi toute ſa largeur ſera de 2 modules 7 parties; </s> <s xml:id="echoid-s9656" xml:space="preserve">la ſaillie des <lb/>3 Reglets eſt d’une partie, celle de l’Ove eſt égale à ſa propre hau-<lb/>teur, celle de la Goûtiere eſt de 4 parties, & </s> <s xml:id="echoid-s9657" xml:space="preserve">la largeur du Gorge-<lb/>rin eſt égale à celle du haut de la Colomne.</s> <s xml:id="echoid-s9658" xml:space="preserve"/> </p> <pb o="20" file="0464" n="503" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s9659" xml:space="preserve">Le Reglet, le Talon, & </s> <s xml:id="echoid-s9660" xml:space="preserve">la Goûtiere de l’Abaque doivent être <lb/>quarrés dans tous les Ordres, & </s> <s xml:id="echoid-s9661" xml:space="preserve">les autres membres arrondis comme <lb/>le Fuſt de la Colomne.</s> <s xml:id="echoid-s9662" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9663" xml:space="preserve">Quand on veut embellir cet Ordre & </s> <s xml:id="echoid-s9664" xml:space="preserve">lui donner plus de délica-<lb/>teſſe, il faut canneler les Colomnes de 20 canelures à vive arrête; <lb/></s> <s xml:id="echoid-s9665" xml:space="preserve">c’eſt-à-dire par des canelures qui ne ſoient point ſeparées avec des <lb/>Reglets de la maniere que nous l’expliquerons plus particulierement <lb/>dans la ſuite: </s> <s xml:id="echoid-s9666" xml:space="preserve">on peut auſſi tailler des Roſes ou Fleurs, ou même <lb/>des Feuilles dans le Gorgerin; </s> <s xml:id="echoid-s9667" xml:space="preserve">&</s> <s xml:id="echoid-s9668" xml:space="preserve">, pour donner plus de grace, au lieu <lb/>de faire 3 Filets au haut du Gorgerin, n’en faire qu’un, & </s> <s xml:id="echoid-s9669" xml:space="preserve">changer les <lb/>deux autres en un Aſtragale retaillé d’olives & </s> <s xml:id="echoid-s9670" xml:space="preserve">de patenotres, & </s> <s xml:id="echoid-s9671" xml:space="preserve">re-<lb/>fendre l’Ove de 20 œufs qui doivent répondre à plomb ſur les ar-<lb/>rêtes des canelures: </s> <s xml:id="echoid-s9672" xml:space="preserve">les olives de l’Aſtragale doivent auſſi être au <lb/>nombre de 20. </s> <s xml:id="echoid-s9673" xml:space="preserve">& </s> <s xml:id="echoid-s9674" xml:space="preserve">répondre juſtement ſous les œufs de l’Ove.</s> <s xml:id="echoid-s9675" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div429" type="section" level="1" n="106"> <head xml:id="echoid-head315" style="it" xml:space="preserve">Entablement Dorique.</head> <p> <s xml:id="echoid-s9676" xml:space="preserve">La hauteur de l’Entablement étant de 4 modules ou de 48 par-<lb/>ties, l’on en donne 12 à l’Architrave, 18 à la Friſe, & </s> <s xml:id="echoid-s9677" xml:space="preserve">18 à la Cor-<lb/>niche; </s> <s xml:id="echoid-s9678" xml:space="preserve">& </s> <s xml:id="echoid-s9679" xml:space="preserve">comme cet Entablement eſt orné de pluſieurs petites par-<lb/>ties qui demandent d’être bien détaillées pour être executées avec <lb/>préciſion, nous allons faire enſorte de ne rien négliger.</s> <s xml:id="echoid-s9680" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9681" xml:space="preserve">Les Goutes au-deſſous des Trigliphes ſont toûjours au nombre <lb/>de 6, diſpoſées de façon que leur intervale en occupe la largeur: <lb/></s> <s xml:id="echoid-s9682" xml:space="preserve">ces Goutes ſont faites en forme de Clochettes, leur ſaillie eſt égale <lb/>à leur hauteur, l’une & </s> <s xml:id="echoid-s9683" xml:space="preserve">l’autre étant d’une partie & </s> <s xml:id="echoid-s9684" xml:space="preserve">demi, ſont <lb/>couronnées par un Filet qui a pour hauteur une demi partie, au-<lb/>deſſus duquel eſt un Reglet de 2 parties, & </s> <s xml:id="echoid-s9685" xml:space="preserve">dont la ſaillie eſt d’une <lb/>partie.</s> <s xml:id="echoid-s9686" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9687" xml:space="preserve">Les Trigliphes ſont élevés dans la Friſe de toute ſa hauteur, <lb/>& </s> <s xml:id="echoid-s9688" xml:space="preserve">ont par conſequent 18 parties, leur largeur eſt de 12 parties, <lb/>ils ſont refendus de 2 Canaux, qui ont chacun 2 parties ſeparées <lb/>par 3 Arêtes, qui ont auſſi 2 parties de largeur & </s> <s xml:id="echoid-s9689" xml:space="preserve">une de ſaillie, ac-<lb/>compagné par chaque côté d’un demi canal, le creux des canaux <lb/>eſt en angle droit, leur hauteur eſt de 16 parties. </s> <s xml:id="echoid-s9690" xml:space="preserve">J’ajouterai, que la <lb/>diſtance d’un Trigliphe à l’autre eſt ordinairement égal à la hau-<lb/>teur de la Friſe, c’eſt-à-dire de 18 parties: </s> <s xml:id="echoid-s9691" xml:space="preserve">cet eſpace, que l’on nom-<lb/>me Metope, eſt orné quelquefois par des noms en chifres, ou par <lb/>quelque autre deſſein fait à fantaiſie, mais qui doivent être ſimples.</s> <s xml:id="echoid-s9692" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9693" xml:space="preserve">De 18 parties que comprend la Corniche, il y en a 2 pour le <lb/>Reglet qui ſert de Chapiteau aux Trigliphes, 2 pour le Talon, un <pb o="21" file="0465" n="504" rhead="LIVRE V. DE LA DE’CORATION."/> demi pour le Filet qui eſt au-deſſus, 3 pour la Bandelette qui eſt <lb/>refenduë par des Denticules, au-deſſus deſquelles eſt une petite Ove <lb/>d’une demi partie: </s> <s xml:id="echoid-s9694" xml:space="preserve">la largeur des Denticules eſt de 2 parties, leur <lb/>intervale d’une partie & </s> <s xml:id="echoid-s9695" xml:space="preserve">demi, la Goûtiere de 4, le Talon de 2 & </s> <s xml:id="echoid-s9696" xml:space="preserve"><lb/>demi, le Filet d’une demie, le Cavet de 3, & </s> <s xml:id="echoid-s9697" xml:space="preserve">le Reglet d’une <lb/>partie.</s> <s xml:id="echoid-s9698" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9699" xml:space="preserve">Toute la ſaillie de la Corniche eſt de 2 modules ou de 24 parties; <lb/></s> <s xml:id="echoid-s9700" xml:space="preserve">ſurquoi la Bandelette des Denticules en a 6, le Larmier 14, faiſant <lb/>attention que les Denticules ſont quarrées par le bas, ayant autant <lb/>de ſaillie que de largeur; </s> <s xml:id="echoid-s9701" xml:space="preserve">à l’égard des ſaillies des autres moulures, <lb/>elles ſont égales à leur hauteur, comme on le voit marqué dans le <lb/>deſſein.</s> <s xml:id="echoid-s9702" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9703" xml:space="preserve">L’on taille ordinairement le Plafond de la Goûtiere, pour y pra-<lb/>tiquer un Canal & </s> <s xml:id="echoid-s9704" xml:space="preserve">des Goûtes, afin de l’orner & </s> <s xml:id="echoid-s9705" xml:space="preserve">de le rendre plus <lb/>leger.</s> <s xml:id="echoid-s9706" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9707" xml:space="preserve">Vitruve ne met point de difference entre le Chapiteau Dorique <lb/>& </s> <s xml:id="echoid-s9708" xml:space="preserve">le Toſcan en ce qui regarde les meſures, il ſe contente ſeulement <lb/>d’y ajoûter quelques ornemens pour le rendre moins nud; </s> <s xml:id="echoid-s9709" xml:space="preserve">mais <lb/>Vignole, & </s> <s xml:id="echoid-s9710" xml:space="preserve">tous les autres Architectes qui ſont venus après, n’ont <lb/>point ſuivi cette conformité, & </s> <s xml:id="echoid-s9711" xml:space="preserve">ont tous donné au Chapiteau Do-<lb/>rique à peu-près les mêmes proportions que nous avons raportéesici.</s> <s xml:id="echoid-s9712" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9713" xml:space="preserve">Vignole a tiré du Théatre de Marcellus le deſſein de l’Ordre <lb/>Dorique que nous venons de donner pour exemple, ſurquoi Mr. <lb/></s> <s xml:id="echoid-s9714" xml:space="preserve">Daviler remarque, que Vitruve n’a point été l’Architecte de ce <lb/>Monument, comme pluſieurs l’ont prétendu, parce que cet Auteur <lb/>étoit contemporain d’Auguſte, dont il étoit l’Ingenieur: </s> <s xml:id="echoid-s9715" xml:space="preserve">d’ailleurs, il <lb/>eſt à préſumer, que s’il y avoit eû part, il en auroit fait mention dans <lb/>ſon Livre; </s> <s xml:id="echoid-s9716" xml:space="preserve">mais, ceci eſt de peu d’importance: </s> <s xml:id="echoid-s9717" xml:space="preserve">on remarquera ſeu-<lb/>lement, que Vignole ne s’eſt pas attaché abſolument à ſuivre les <lb/>proportions du Théatre de Marcellus, parce que s’étant aperçû que <lb/>les membres de chaque partie n’étoient pas aſſés bien proportion-<lb/>nez entre eux, il a fait les changemens qu’il a jugé les plus neceſ-<lb/>ſaires; </s> <s xml:id="echoid-s9718" xml:space="preserve">par exemple, ayant trouvé que la Corniche n’étoit pas aſſés <lb/>élevée, il a ajoûté quelques moulures au-deſſous du Larmier, & </s> <s xml:id="echoid-s9719" xml:space="preserve"><lb/>par-là la hauteur de la Corniche ſe trouve égale à celle de la Friſe, <lb/>ce qui lui donne plus de grace & </s> <s xml:id="echoid-s9720" xml:space="preserve">de dégagement: </s> <s xml:id="echoid-s9721" xml:space="preserve">dailleurs, la plate-<lb/>bande, qui ſert ici de Chapiteau aux Trigliphes, fait partie de la <lb/>Corniche, & </s> <s xml:id="echoid-s9722" xml:space="preserve">non pas de la Friſe, ce qui eſt tout le contraire dans <lb/>les deſſeins que nous avons de ce Théatre.</s> <s xml:id="echoid-s9723" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9724" xml:space="preserve">Vignole raporte encore un autre Entablement de l’Ordre Do-<lb/>rique, qu’il a tiré à Rome de pluſieurs Fragmens antiques, & </s> <s xml:id="echoid-s9725" xml:space="preserve">que <pb o="22" file="0466" n="505" rhead="LA SCIENCE DES INGENIEURS,"/> l’on peut voir ſur la Planche 48. </s> <s xml:id="echoid-s9726" xml:space="preserve">qu’il eſt peu different de celui <lb/>dont nous venons de parler: </s> <s xml:id="echoid-s9727" xml:space="preserve">tout ce qu’on y trouve de plus re-<lb/>marquable, c’eſt qu’on n’y voit point de Denticule.</s> <s xml:id="echoid-s9728" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div430" type="section" level="1" n="107"> <head xml:id="echoid-head316" xml:space="preserve">CHAPITRE CINQUIE’ME.</head> <head xml:id="echoid-head317" style="it" xml:space="preserve">De l’Ordre Ionique.</head> <p> <s xml:id="echoid-s9729" xml:space="preserve">AYANT fait remarquer dans le ſecond Chapitre, que les <lb/>Trigliphes étoient des membres qui apartenoient particu-<lb/>lierement à l’Ordre Dorique, & </s> <s xml:id="echoid-s9730" xml:space="preserve">qui ſervoient à le faire reconnoître <lb/>entre les autres, de même que les Volutes du Chapiteau Ionique <lb/>étoient affectées à cet Ordre, ce qui ſert à le diſtinguer auſſi des <lb/>autres; </s> <s xml:id="echoid-s9731" xml:space="preserve">j’ajoûterai ici que les Voulutes ont été regardées par les An-<lb/>ciens comme exprimant les coëffures des anciennes Dames de la <lb/>Grece, & </s> <s xml:id="echoid-s9732" xml:space="preserve">que les canelures des Colomnes avoient été faites à l’imi-<lb/>tation des plis de leurs robes: </s> <s xml:id="echoid-s9733" xml:space="preserve">il y a des Auteurs, qui ne ſont point <lb/>de ce ſentiment, & </s> <s xml:id="echoid-s9734" xml:space="preserve">qui veulent que les Voulutes ayent été faites pour <lb/>repréſenter les pentes roulées des couſſinets que l’on feignoit avoir <lb/>mis ſur la tête des Cariatides, pour leur donner moins de peine à <lb/>porter le poids des Architraves; </s> <s xml:id="echoid-s9735" xml:space="preserve">mais, ce qu’il y a de certain, c’eſt <lb/>que l’Ordre Ionique a toûjours été regardé des Grecs, & </s> <s xml:id="echoid-s9736" xml:space="preserve">des Ro-<lb/>mains, comme étant le ſymbole du beau ſexe.</s> <s xml:id="echoid-s9737" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div431" type="section" level="1" n="108"> <head xml:id="echoid-head318" style="it" xml:space="preserve">Piédeſtal Ionique.</head> <p> <s xml:id="echoid-s9738" xml:space="preserve">La hauteur du Piédeſtal qui eſt de 6 modules ſe partage, en-<lb/>ſorte que la Baſe ait un demi-module & </s> <s xml:id="echoid-s9739" xml:space="preserve">la Corniche autant, ainſi <lb/>il reſte 5 modules pour la hauteur du Dé.</s> <s xml:id="echoid-s9740" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9741" xml:space="preserve">La Baſe eſt compoſée d’une Plinthe de 4 parties, d’un Filet de <lb/> <anchor type="note" xlink:label="note-0466-01a" xlink:href="note-0466-01"/> deux tiers, d’une Doucine de 3 parties, & </s> <s xml:id="echoid-s9742" xml:space="preserve">d’une Aſtragale d’une par-<lb/>tie & </s> <s xml:id="echoid-s9743" xml:space="preserve">un tiers.</s> <s xml:id="echoid-s9744" xml:space="preserve"/> </p> <div xml:id="echoid-div431" type="float" level="2" n="1"> <note position="left" xlink:label="note-0466-01" xlink:href="note-0466-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>40.</note> </div> <note position="left" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> <p> <s xml:id="echoid-s9745" xml:space="preserve">La ſaillie de la Plinthe eſt de 8 parties, celle du Filet de 7, & </s> <s xml:id="echoid-s9746" xml:space="preserve"><lb/>celle du centre de l’Aſtragale de 6.</s> <s xml:id="echoid-s9747" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9748" xml:space="preserve">La largeur du Dé doit être de 2 modules 14 parties, ſes mou-<lb/>lures ſont les Reglets du deſſous & </s> <s xml:id="echoid-s9749" xml:space="preserve">du deſſus avec leurs Chamfrains <lb/>qui ont chacun une partie, la ſaillie du Reglet d’enbas eſt d’une <lb/>partie, & </s> <s xml:id="echoid-s9750" xml:space="preserve">celle d’enhaut de deux.</s> <s xml:id="echoid-s9751" xml:space="preserve"/> </p> <pb o="23" file="0467" n="506" rhead="LIVRE V. DE LA DE’CORATION."/> <p> <s xml:id="echoid-s9752" xml:space="preserve">Les moulures de la Corniche ſont l’Aſtragale, qui a une partie, <lb/>l’Ove en a 3, la Goutiere auſſi 3, le Talon 1 & </s> <s xml:id="echoid-s9753" xml:space="preserve">un tiers, & </s> <s xml:id="echoid-s9754" xml:space="preserve">le Re-<lb/>glet 2 tiers ſeulement, la ſaillie de toute la Corniche eſt de 10 par-<lb/>ties, celle de la Goûtiere de 8, & </s> <s xml:id="echoid-s9755" xml:space="preserve">celle du haut de l’Ove 5.</s> <s xml:id="echoid-s9756" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div433" type="section" level="1" n="109"> <head xml:id="echoid-head319" style="it" xml:space="preserve">Colomne Ionique.</head> <p> <s xml:id="echoid-s9757" xml:space="preserve">La Baſe de la Colomne a pour hauteur un module, elle eſt <lb/>compoſée de la Plinthe qui a 6 parties, de l’Orle ou Anneau qui <lb/>n’a qu’un quart, de la Scotie qui a 2 parties, d’un autre Anneau <lb/>d’un quart, enſuite ſont 2 Aſtragales immédiatement l’un ſur l’autre <lb/>qui ont chacun une partie, au-deſſus eſt encore un Orlet d’un quart <lb/>de partie, & </s> <s xml:id="echoid-s9758" xml:space="preserve">une Scotie de 2 parties, un Filet d’un quart, le <lb/>tout terminé par un Tore de 5 parties.</s> <s xml:id="echoid-s9759" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9760" xml:space="preserve">Toute la ſaillie de la Baſe eſt de 7 parties de chaque côté afin <lb/>que la largeur ou le front de la Plinthe ſoit le même que le front <lb/>du Piédeſtal que nous avons dit cy-devant être de 2 modules 14 <lb/>parties, la ſaillie de l’Orle qui eſt ſur la Plinthe eſt de 6 parties & </s> <s xml:id="echoid-s9761" xml:space="preserve"><lb/>demi, celle des 2 Aſtragales & </s> <s xml:id="echoid-s9762" xml:space="preserve">du Tore de 5, & </s> <s xml:id="echoid-s9763" xml:space="preserve">celle du Reglet <lb/>qui eſt ſous le Tore de 2 & </s> <s xml:id="echoid-s9764" xml:space="preserve">demi.</s> <s xml:id="echoid-s9765" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9766" xml:space="preserve">La hauteur du Fuſt de la Colomne eſt de 16 modules 6 parties, <lb/> <anchor type="note" xlink:label="note-0467-01a" xlink:href="note-0467-01"/> le Reglet ou Orle de deſſous avec ſon Conge ou Cavet 1 partie <lb/> <anchor type="note" xlink:label="note-0467-02a" xlink:href="note-0467-02"/> & </s> <s xml:id="echoid-s9767" xml:space="preserve">demi, le Tronc de la Colomne 16 modules & </s> <s xml:id="echoid-s9768" xml:space="preserve">une partie & </s> <s xml:id="echoid-s9769" xml:space="preserve"><lb/>demi, l’Orle de deſſus avec ſon Conge 1 partie, & </s> <s xml:id="echoid-s9770" xml:space="preserve">l’Aſtragale 2 <lb/>parties.</s> <s xml:id="echoid-s9771" xml:space="preserve"/> </p> <div xml:id="echoid-div433" type="float" level="2" n="1"> <note position="right" xlink:label="note-0467-01" xlink:href="note-0467-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>41.</note> <note position="right" xlink:label="note-0467-02" xlink:href="note-0467-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s9772" xml:space="preserve">La ſaillie des Orles avec les Chamfarins, eſt de 2 parties, & </s> <s xml:id="echoid-s9773" xml:space="preserve">celle <lb/>de l’Aſtagale de 3: </s> <s xml:id="echoid-s9774" xml:space="preserve">la largeur de la Colomne par le bas eſt de 2 mo-<lb/>dules qui ſe conduit également juſqu’au tiers de la hauteur, d’où <lb/>elle eſt inſenſiblement diminuée juſques ſous l’Orle de deſſus, où <lb/>ſa largeur eſt reduite à un module & </s> <s xml:id="echoid-s9775" xml:space="preserve">12 parties, afin que la dimi-<lb/>nution ſoit de 3 parties de chaque côté.</s> <s xml:id="echoid-s9776" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9777" xml:space="preserve">Si l’on veut canneler les Colomnes Ioniques, il faut premiere-<lb/> <anchor type="note" xlink:label="note-0467-03a" xlink:href="note-0467-03"/> ment faire le plan du Fuſt à l’endroit de la baſe, c’eſt-à-dire qu’on <lb/>tracera un cercle dont le diamêtre ſera de 2 modules, enſuite on <lb/>en diviſera la circonference en 24 parties égales, tel que AB qu’il <lb/>faut partager chacune en 5 autres parties, aux points 1, 2, 3, & </s> <s xml:id="echoid-s9778" xml:space="preserve">4, <lb/>& </s> <s xml:id="echoid-s9779" xml:space="preserve">l’une de ces parties comme C, marque l’épaiſſeur des côtés ou <lb/>liſtels des Cannelures, & </s> <s xml:id="echoid-s9780" xml:space="preserve">les autres 4, comme A 4 ou BD, déter-<lb/>minent le creux ou le fond qui ſe fouille dans le vif de la Colom-<lb/>ne en forme d’un demi cercle, qui auroit pour diamêtre l’interva-<lb/>le A 4 ou BD; </s> <s xml:id="echoid-s9781" xml:space="preserve">ſes moulures ſont conduites depuis le pied de la <pb o="24" file="0468" n="507" rhead="LA SCIENCE DES INGENIEURS,"/> Colomne juſqu’au deſſous de l’Orle ſuperieure, enſorte que les li-<lb/>gnes montantes ſuivent toûjours entre elles le contour de la dimi-<lb/>nution de la Colomne, pour s’aprocher avec la même proportion; <lb/></s> <s xml:id="echoid-s9782" xml:space="preserve">ainſi la Colomne ſe trouve cannelée agreablement, & </s> <s xml:id="echoid-s9783" xml:space="preserve">ſuivant les <lb/>regles de la bonne Architecture, avec 24 creux & </s> <s xml:id="echoid-s9784" xml:space="preserve">autant de can-<lb/>nelures qui ſeront chacune égale au quart de la largeur du creux, <lb/>quoi qu’elles puiſſent être quelquefois plus grandes, enſorte nean-<lb/>moins qu’elles ne paſſent jamais au-deſſus du tiers, & </s> <s xml:id="echoid-s9785" xml:space="preserve">jamais au-<lb/>deſſous du cinquiéme du même creux, qui ſont les termes que les <lb/>Anciens ſe ſont preſcrits dans leurs cannelures.</s> <s xml:id="echoid-s9786" xml:space="preserve"/> </p> <div xml:id="echoid-div434" type="float" level="2" n="2"> <note position="right" xlink:label="note-0467-03" xlink:href="note-0467-03a" xml:space="preserve"><emph style="sc">Fig</emph>. 6.</note> </div> </div> <div xml:id="echoid-div436" type="section" level="1" n="110"> <head xml:id="echoid-head320" style="it" xml:space="preserve">Chapiteau Ionique.</head> <p> <s xml:id="echoid-s9787" xml:space="preserve">La hauteur du Chapiteau ſe fait de 12 parties, non compris la <lb/> <anchor type="note" xlink:label="note-0468-01a" xlink:href="note-0468-01"/> pente des Volutes, ſes moulures ſont l’Ove qui a 5 parties, la Plat-<lb/>te-Bande des Couſſinets des Volutes 3, la Bandelette ou Bordure <lb/>1, la Cimaiſe ou Talon de l’Abaque 2, & </s> <s xml:id="echoid-s9788" xml:space="preserve">la Regle de l’Abaque 1.</s> <s xml:id="echoid-s9789" xml:space="preserve"/> </p> <div xml:id="echoid-div436" type="float" level="2" n="1"> <note position="left" xlink:label="note-0468-01" xlink:href="note-0468-01a" xml:space="preserve"><emph style="sc">Fig</emph>. 3. <lb/>& 8.</note> </div> <p> <s xml:id="echoid-s9790" xml:space="preserve">Toute la ſaillie de l’Ove eſt de 7 parties, celle de l’Abaque en <lb/>a 5, celle des bordures des Volutes 4 & </s> <s xml:id="echoid-s9791" xml:space="preserve">demi, & </s> <s xml:id="echoid-s9792" xml:space="preserve">celle du fond <lb/>ou creux de la Platte-Bande du Couſſinet des Voulutes ſur l’Ove <lb/>6 & </s> <s xml:id="echoid-s9793" xml:space="preserve">demi.</s> <s xml:id="echoid-s9794" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9795" xml:space="preserve">La perpendiculaire, ou Catele CD de l’œil des Volutes, paſſe par <lb/>le milieu AB de toute la ſaillie de l’Abaque: </s> <s xml:id="echoid-s9796" xml:space="preserve">ſa longueur FD ſous <lb/>l’Abaque eſt de 16 parties, & </s> <s xml:id="echoid-s9797" xml:space="preserve">le centre E de l’œil ſe prend ſur la <lb/>9<emph style="sub">e</emph>. </s> <s xml:id="echoid-s9798" xml:space="preserve">enſorte qu’il y a 9 parties de F en E, & </s> <s xml:id="echoid-s9799" xml:space="preserve">7 de E en D. </s> <s xml:id="echoid-s9800" xml:space="preserve">On verra <lb/>par la ſuite comme on trouve dans l’œil de la Volute les centres <lb/>qui ſervent à la former, auſſi-bien que ceux qui donnent les Arcs <lb/>de la bordure ou Volute interieure.</s> <s xml:id="echoid-s9801" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9802" xml:space="preserve">Toute la face ou largeur de l’Abaque eſt de 2 modules 4 parties, <lb/>celle des Volutes par devant, & </s> <s xml:id="echoid-s9803" xml:space="preserve">par derriere, eſt de 2 modules 11 <lb/>parties, comme on le peut voir dans la figure 8 de la Planche 40, <lb/>qui repréſente tout le Chapiteau vu par le deſſous: </s> <s xml:id="echoid-s9804" xml:space="preserve">la largeur de la <lb/>face des côtés du Chapiteau eſt d’un module 17 parties, la largeur <lb/>de la Ceinture qui eſt entre les Baluſtres, ou qui attache le Couſſi-<lb/>net des Volutes ſur les côtés, eſt de 6 parties, avec un Filet de part <lb/>& </s> <s xml:id="echoid-s9805" xml:space="preserve">d’autre de 1 partie, elle prend ſon origine ſous le Talon de l’A-<lb/>baque, d’où elle deſcend inſenſiblement ſur la partie de l’Ove, <lb/>qu’elle embraſſe de-là avec un contour agreable, juſques ſur l’Orle <lb/>ſuperieur du Fuſt de la Colomne, d’où enfin elle remonte en <lb/>s’arrondiſſant en dedans ſur l’Aſtragale, pour ſe venir perdre au-deſ-<lb/>ſous de l’Ove, les extrémités des Baluſtres ſont enfermées d’un Ru- <pb o="25" file="0469" n="508" rhead="LIVRE V. DE LA DE’CORATION."/> ban ou Orle, qui a pour largeur 2 parties, enfin on taille des œufs <lb/>dans l’Ove qui répondent au vif des Cannelures. </s> <s xml:id="echoid-s9806" xml:space="preserve">Tout ceci s’en-<lb/>tendra parfaitement ſi l’on conſidere les deſſeins qui ſont relatifs à <lb/>ce diſcours.</s> <s xml:id="echoid-s9807" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9808" xml:space="preserve">Scamozzy fait le Chapiteau Ionique different de celui de Vigno-<lb/>le, comme on en peut juger par la figure 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s9809" xml:space="preserve">de la 41<emph style="sub">e</emph>. </s> <s xml:id="echoid-s9810" xml:space="preserve">Planche & </s> <s xml:id="echoid-s9811" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0469-01a" xlink:href="note-0469-01"/> la 9e. </s> <s xml:id="echoid-s9812" xml:space="preserve">de la 40<emph style="sub">e</emph>. </s> <s xml:id="echoid-s9813" xml:space="preserve">Ce Chapiteau a fort bonne grace & </s> <s xml:id="echoid-s9814" xml:space="preserve">paroit aprouvé <lb/> <anchor type="note" xlink:label="note-0469-02a" xlink:href="note-0469-02"/> des meilleurs Architectes; </s> <s xml:id="echoid-s9815" xml:space="preserve">&</s> <s xml:id="echoid-s9816" xml:space="preserve">, afin d’être mieux inſtruit des particu-<lb/> <anchor type="note" xlink:label="note-0469-03a" xlink:href="note-0469-03"/> larités qui lui apartiennent eſſentiellement, voici l’Explication qu’en <lb/> <anchor type="note" xlink:label="note-0469-04a" xlink:href="note-0469-04"/> donne Scamozzy lui-même dans le Chapitre 23 du 6<emph style="sub">e</emph> Livre de ſon <lb/>Idée generale d’ Architecture, où, après avoir décrit le Chapiteau Io-<lb/>nique ordinaire, il continue en ces termes.</s> <s xml:id="echoid-s9817" xml:space="preserve"/> </p> <div xml:id="echoid-div437" type="float" level="2" n="2"> <note position="right" xlink:label="note-0469-01" xlink:href="note-0469-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>41.</note> <note position="right" xlink:label="note-0469-02" xlink:href="note-0469-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> <note position="right" xlink:label="note-0469-03" xlink:href="note-0469-03a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>40.</note> <note position="right" xlink:label="note-0469-04" xlink:href="note-0469-04a" xml:space="preserve"><emph style="sc">Fig</emph>. 9.</note> </div> <p> <s xml:id="echoid-s9818" xml:space="preserve">Il faut à preſent, dit-il, expliquer un autre Chapiteau Ionique <lb/>de nôtre Invention, imité de l’Antique & </s> <s xml:id="echoid-s9819" xml:space="preserve">de Vitruve en partie, qui <lb/>eſt different des autres qui ont été faits juſqu’à preſent, en ce que <lb/>l’Abaque eſt dégagé pardeſſous, que les Voulutes ſont angulaires, <lb/>que les 4 faces en ſont égales, & </s> <s xml:id="echoid-s9820" xml:space="preserve">qu’il a beaucoup de raport à la <lb/>partie ſuperieure du Chapiteau Corinthien: </s> <s xml:id="echoid-s9821" xml:space="preserve">il eſt ſi regulier en <lb/>ſes parties, & </s> <s xml:id="echoid-s9822" xml:space="preserve">réüſſit avec tant de grace, qu’il a été mis en œu-<lb/>vre à la plûpart des Bâtimens que nous avons faits.</s> </p> <p> <s xml:id="echoid-s9823" xml:space="preserve">Son Plan quarré a un module & </s> <s xml:id="echoid-s9824" xml:space="preserve">un tiers à chaque face, il y <lb/>faut tracer des lignes diamêtrales & </s> <s xml:id="echoid-s9825" xml:space="preserve">d’autres diagonales qui ſe croi-<lb/>ſent & </s> <s xml:id="echoid-s9826" xml:space="preserve">qui ſe diviſent en 8 parties égales: </s> <s xml:id="echoid-s9827" xml:space="preserve">du centre on décrit la <lb/>circonference du diamêtre ſuperieur & </s> <s xml:id="echoid-s9828" xml:space="preserve">celle du Liſteau & </s> <s xml:id="echoid-s9829" xml:space="preserve">de <lb/>l’Aſtragale.</s> </p> <p> <s xml:id="echoid-s9830" xml:space="preserve">Enſuite ſur chaque diagonale il faut tracer à l’équerre une ligne <lb/>diſtante du centre d’un module moins un huitiéme, ainſi la diago-<lb/>nale reſte en tout longue d’un module 3 quarts: </s> <s xml:id="echoid-s9831" xml:space="preserve">cette ligne à cha-<lb/>cune des extrêmités des diagonales, fait les cornes de l’Abaque qui <lb/>ont 2 parties trois quarts de largeur, les 8 angles touchent les 4 cô-<lb/>tés du quarré, & </s> <s xml:id="echoid-s9832" xml:space="preserve">ſur un des côtés d’un des points qui le touche <lb/>il faut prendre la Baſe d’un triangle équilateral & </s> <s xml:id="echoid-s9833" xml:space="preserve">de ſon ſom-<lb/>met, tracer la ligne courbe de la face de l’Abaque, la profon-<lb/>deur de cette courbe ſera de 2 douziémes & </s> <s xml:id="echoid-s9834" xml:space="preserve">demi de module, <lb/>de ſorte que d’une courbure à l’autre, il y aura un module & </s> <s xml:id="echoid-s9835" xml:space="preserve">un <lb/>douziéme comme nous avons dit cy-devant, ce qui peut encore <lb/>ſervir pour faire l’Abaque quarré.</s> </p> <p> <s xml:id="echoid-s9836" xml:space="preserve">Au milieu de chaque face de l’Abaque, il faut mettre une <lb/>Fleur large d’un cinquiéme module ou de 3 parties, de 2 cinquié-<lb/>mes des 18, depuis l’extrémité de l’Aſtragale juſqu’à celle de la <lb/>corne de l’Abaque, il y aura 7 parties de largeur, le deſſous des <pb o="26" file="0470" n="509" rhead="LA SCIENCE DES INGENIEURS,"/> Volutes eſt de 2 parties & </s> <s xml:id="echoid-s9837" xml:space="preserve">3 quarts vers le devant, & </s> <s xml:id="echoid-s9838" xml:space="preserve">elles s’élar-<lb/>giſſent en dedans, & </s> <s xml:id="echoid-s9839" xml:space="preserve">s’éloignent de l’Ove & </s> <s xml:id="echoid-s9840" xml:space="preserve">entrent deſſous l’Aba-<lb/>que; </s> <s xml:id="echoid-s9841" xml:space="preserve">ſous les Fleurs regne l’Ove qui ſaille à chaque face de demi <lb/>partie plus que la courbure de l’Abaque, ce qui eſt pour le Plan.</s> </p> <p> <s xml:id="echoid-s9842" xml:space="preserve">La hauteur de ce Chapiteau avec ſes Volutes eſt de 9 parties <lb/>& </s> <s xml:id="echoid-s9843" xml:space="preserve">5 huitiémes des 18 du bas de la Colomne, nous nous ſervons <lb/>de ces meſures pour faire la diviſion & </s> <s xml:id="echoid-s9844" xml:space="preserve">donner les hauteurs des <lb/>parties. </s> <s xml:id="echoid-s9845" xml:space="preserve">L’Abaque a de front un module & </s> <s xml:id="echoid-s9846" xml:space="preserve">un tiers, ſa hauteur <lb/>eſt d’une partie & </s> <s xml:id="echoid-s9847" xml:space="preserve">de 5 huitiémes, qui comprennent le Filet & </s> <s xml:id="echoid-s9848" xml:space="preserve">le <lb/>Talon qui a une partie de ſaillie égale à ſa hauteur, ſous l’Aba-<lb/>que le Liſteau & </s> <s xml:id="echoid-s9849" xml:space="preserve">la Volute a une partie, & </s> <s xml:id="echoid-s9850" xml:space="preserve">le membre creux de <lb/>la Volute qui poſe ſur l’Ove une partie & </s> <s xml:id="echoid-s9851" xml:space="preserve">demi.</s> </p> <p> <s xml:id="echoid-s9852" xml:space="preserve">L’Ove a 2 parties de ce membre creuſé qui eſt à la Volute & </s> <s xml:id="echoid-s9853" xml:space="preserve"><lb/>finit ſur l’Aſtragale qui détermine le haut du Fuſt de la Colomne, <lb/>il y a un module & </s> <s xml:id="echoid-s9854" xml:space="preserve">un neuviéme de diamêtre, l’Aſtragale a une <lb/>partie de hauteur & </s> <s xml:id="echoid-s9855" xml:space="preserve">répond à l’œil de la Volute, le Liſteau au-<lb/>deſſous a 2 cinquiémes de cette partie, & </s> <s xml:id="echoid-s9856" xml:space="preserve">ſes membres doivent <lb/>être toûjours dégagés des Volutes qui pendent plus bas que le <lb/>Liſteau de 2 parties 2 cinquiémes.</s> </p> <p> <s xml:id="echoid-s9857" xml:space="preserve">Les Volutes depuis le deſſous de l’Abaque ont 8 parties de haut, <lb/>7 de large, & </s> <s xml:id="echoid-s9858" xml:space="preserve">leur épaiſſeur ſous la corne de l’Abaque eſt de 2 <lb/>parties 3 quarts, elles commencent à côté de la Fleur ſur l’Ove & </s> <s xml:id="echoid-s9859" xml:space="preserve"><lb/>ſe vont courber ſous la corne de l’Abaque, l’œil de la Volute qui <lb/>eſt d’une partie doit être de niveau avec l’Aſtragale; </s> <s xml:id="echoid-s9860" xml:space="preserve">dans le milieu <lb/>de l’œil on fait un quarré plus petit de moitié que le diamêtre & </s> <s xml:id="echoid-s9861" xml:space="preserve"><lb/>parallele aux lignes croiſées: </s> <s xml:id="echoid-s9862" xml:space="preserve">les diagonales de ce quarré ſe divi-<lb/>ſent en 6 parties égales qui font en tout 12 centres pour les tours <lb/>de la Volute, il faut prendre garde que les centres angulaires <lb/>ſont éloignés entr’eux d’une demi partie, ceux des lignes du <lb/>quarré d’un tiers de partie, & </s> <s xml:id="echoid-s9863" xml:space="preserve">ainſi la Volute diminue dans les <lb/>trois tours de ſes 12 quartiers.</s> </p> <p> <s xml:id="echoid-s9864" xml:space="preserve">Il y a 4 parties & </s> <s xml:id="echoid-s9865" xml:space="preserve">demi depuis le centre de l’œil juſques ſous <lb/>l’Abaque, & </s> <s xml:id="echoid-s9866" xml:space="preserve">4 depuis le centre juſqu’au dehors de la Volute qui <lb/>eſt à plomb ſous la face de la corne de l’Abaque, il y en a 3 & </s> <s xml:id="echoid-s9867" xml:space="preserve">de-<lb/>mi de ce même centre juſqu’au bas de la Volute; </s> <s xml:id="echoid-s9868" xml:space="preserve">ainſi elle di-<lb/>minuë de 2 parties dans le premier tour, c’eſt-à-dire une demi <lb/>partie pour chaque quartier; </s> <s xml:id="echoid-s9869" xml:space="preserve">& </s> <s xml:id="echoid-s9870" xml:space="preserve">dans le tour elle diminuë de 2 <lb/>tiers de parties, c’eſt-à-dire d’un ſixiéme pour chaque quartier, <lb/>de ſorte que c’eſt 4 parties pour les trois tours qui ſont dans l’eſ-<lb/>pace contenu depuis le deſſous de l’Abaque juſques ſur l’œil.</s> </p> <pb o="27" file="0471" n="510" rhead="LIVRE V. DE LA DE’CORATION."/> </div> <div xml:id="echoid-div439" type="section" level="1" n="111"> <head xml:id="echoid-head321" style="it" xml:space="preserve">Entablement Ionique.</head> <p> <s xml:id="echoid-s9871" xml:space="preserve">La hauteur de l’Architrave ſe fait d’un module 4 parties & </s> <s xml:id="echoid-s9872" xml:space="preserve">demi, <lb/>on donne 4 parties & </s> <s xml:id="echoid-s9873" xml:space="preserve">demi à la premiere Platte-Bande, 6 à la <lb/>ſeconde, 7 & </s> <s xml:id="echoid-s9874" xml:space="preserve">demi à la troiſiéme, 3 au Talon, & </s> <s xml:id="echoid-s9875" xml:space="preserve">une & </s> <s xml:id="echoid-s9876" xml:space="preserve">demi à la <lb/>Regle.</s> <s xml:id="echoid-s9877" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9878" xml:space="preserve">La premiere Bande repond au vif de la Colomne, la ſaillie de <lb/> <anchor type="note" xlink:label="note-0471-01a" xlink:href="note-0471-01"/> chacune des 2 autres eſt d’une partie, la Regle & </s> <s xml:id="echoid-s9879" xml:space="preserve">le Talon en ont <lb/> <anchor type="note" xlink:label="note-0471-02a" xlink:href="note-0471-02"/> cinq.</s> <s xml:id="echoid-s9880" xml:space="preserve"/> </p> <div xml:id="echoid-div439" type="float" level="2" n="1"> <note position="right" xlink:label="note-0471-01" xlink:href="note-0471-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>41.</note> <note position="right" xlink:label="note-0471-02" xlink:href="note-0471-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 3.</note> </div> <p> <s xml:id="echoid-s9881" xml:space="preserve">La Friſe a pour hauteur un module & </s> <s xml:id="echoid-s9882" xml:space="preserve">demi, elle ſe fait à plomb <lb/>& </s> <s xml:id="echoid-s9883" xml:space="preserve">répond au vif du haut de la Colomne, de même que la premiere <lb/>Platte-Bande, l’on peut y entailler des ornemens compoſés de Fi-<lb/>gures, de Fleurs, ou de Feuilles.</s> <s xml:id="echoid-s9884" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9885" xml:space="preserve">La hauteur de la Corniche eſt d’un module 13 parties & </s> <s xml:id="echoid-s9886" xml:space="preserve">demi, <lb/>ſes moulures ſont compoſées d’abord d’un Talon qui a 4 parties, de <lb/>la Regle qui en a 1, de la Bandelette des Denticules qui en a 6, <lb/>d’un Filet qui a une demi partie, d’un Aſtragale d’une partie, de <lb/>l’Ove qui en a 4, du Larmier qui en a 6, d’un Talon au-deſſus qui <lb/>en a 2, d’un Filet qui en a une demi, de la Doucine qui a 5 parties, <lb/>& </s> <s xml:id="echoid-s9887" xml:space="preserve">de la Regle qui en a 1 & </s> <s xml:id="echoid-s9888" xml:space="preserve">demi.</s> <s xml:id="echoid-s9889" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9890" xml:space="preserve">Toute la ſaillie de la Corniche eſt de 31 parties, celle de la Regle <lb/>eſt de 5, ſurquoi il faut en ajoûter 4 pour la ſaillie des Denticu-<lb/>les, 4 & </s> <s xml:id="echoid-s9891" xml:space="preserve">demi pour celle de l’Ove, 10 pour celle de la Goûtiere, <lb/>2 & </s> <s xml:id="echoid-s9892" xml:space="preserve">demi pour le Filet, & </s> <s xml:id="echoid-s9893" xml:space="preserve">5 pour la ſaillie de la Regle.</s> <s xml:id="echoid-s9894" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9895" xml:space="preserve">La hauteur des Denticules ſe fait de 6 parties, leur largeur de 4 <lb/>ſur autant de ſaillie, & </s> <s xml:id="echoid-s9896" xml:space="preserve">eſpacées de 2 parties: </s> <s xml:id="echoid-s9897" xml:space="preserve">ſur le haut du vuide <lb/>de ces intervales, on laiſſe en dedans une Regle qui a pour hauteur <lb/>une partie & </s> <s xml:id="echoid-s9898" xml:space="preserve">demi.</s> <s xml:id="echoid-s9899" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9900" xml:space="preserve">Quand on fouille des Feuillages ſur le Talon des Cimaiſes, des <lb/>œufs dans l’Ove, & </s> <s xml:id="echoid-s9901" xml:space="preserve">des grains d’Olive ou de Patenotres dans les Aſ-<lb/>tragales, on le doit faire de maniere que le Olives répondent à <lb/>plomb ſous les œufs, & </s> <s xml:id="echoid-s9902" xml:space="preserve">les œufs ſous les Denticules, auſſi-bien <lb/>que les Tiges des Feuillages de la Cimaiſe.</s> <s xml:id="echoid-s9903" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div441" type="section" level="1" n="112"> <head xml:id="echoid-head322" style="it" xml:space="preserve">Maniere de tracer la Volute Ionique.</head> <p> <s xml:id="echoid-s9904" xml:space="preserve">Pluſieurs ſçavans Architectes ont cherché des métodes pour tra-<lb/>cer la Volute Ionique, afin de lui donner cette forme agréable qu’on <lb/>remarque dans les Chapiteaux antiques; </s> <s xml:id="echoid-s9905" xml:space="preserve">car l’on a ignoré juſqu’ici <lb/>de quelle maniere les Anciens s’y ſont pris, ne nous étant reſté que <lb/>les Ecritsde Vitruve qui ne ſatisfont point aſſés, ce qui a été cauſe <pb o="28" file="0472" n="511" rhead="LA SCIENCE DES INGENIEURS,"/> qu’on a regardé long-tems la Deſcription de la Volute comme un <lb/>Problême fort interreſſant. </s> <s xml:id="echoid-s9906" xml:space="preserve">Vignole en donne deux ſolutions diffe-<lb/>rentes dont la pratique eſt aiſée, mais peu exactes, ainſi que plu-<lb/>ſieurs autres, dont je ne ferai pas mention.</s> <s xml:id="echoid-s9907" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9908" xml:space="preserve">Le plus ſûr moyen d’inſtruire un Lecteur à peu de frais, étant de <lb/>lui mettre d’abord ſous les yeux ce qu’il y a de meilleur, je me <lb/>contenteray de raporter ſeulement la Volute de Goldman, qui eſt <lb/>la plus eſtimée de toutes celles qu’on a imaginées juſqu’ici, parce <lb/>qu’elle ſe décrit Géometriquement auſſi-bien que le Liſtel ou <lb/>Volute interieure.</s> <s xml:id="echoid-s9909" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9910" xml:space="preserve">Supoſant qu’on a déterminé la grandeur du module qui doit ſer-<lb/> <anchor type="note" xlink:label="note-0472-01a" xlink:href="note-0472-01"/> vir à régler l’Ordonnance Ionique, on le diviſera comme je l’ai déja <lb/> <anchor type="note" xlink:label="note-0472-02a" xlink:href="note-0472-02"/> dit en 18 parties égales, on tirera une ligne AB, à laquelle on don-<lb/>nera 16 de ces parties, ou ſi l’on veut un module moins 2 parties, <lb/>enſuite on déterminera dans cette lignele point E enſorte qu’il ſoit <lb/>éloigné de 9 parties de l’extrémité A, & </s> <s xml:id="echoid-s9911" xml:space="preserve">de 7 del’extrémité B. </s> <s xml:id="echoid-s9912" xml:space="preserve">Ce <lb/>point ſera le centre de l’œil de la Volute, & </s> <s xml:id="echoid-s9913" xml:space="preserve">pour avoir cet œil, <lb/>on décrira un Cercle quiaura pour centre le point E, & </s> <s xml:id="echoid-s9914" xml:space="preserve">pour rayon <lb/>une partie, alors le diamêtre CD ſera de 2 parties, la ligne CA <lb/>de 8, & </s> <s xml:id="echoid-s9915" xml:space="preserve">la ligne DB de 6, ainſi que le preſcrit Vignole.</s> <s xml:id="echoid-s9916" xml:space="preserve"/> </p> <div xml:id="echoid-div441" type="float" level="2" n="1"> <note position="left" xlink:label="note-0472-01" xlink:href="note-0472-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>42.</note> <note position="left" xlink:label="note-0472-02" xlink:href="note-0472-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 5.</note> </div> <p> <s xml:id="echoid-s9917" xml:space="preserve">Cela poſé, il faut diviſer les demis diamêtres EC & </s> <s xml:id="echoid-s9918" xml:space="preserve">ED, en 2 éga-<lb/>lement aux points 1 & </s> <s xml:id="echoid-s9919" xml:space="preserve">4, & </s> <s xml:id="echoid-s9920" xml:space="preserve">ſur la ligne 1. </s> <s xml:id="echoid-s9921" xml:space="preserve">4, qui ſera égale au rayon, <lb/>faire le quarré 1. </s> <s xml:id="echoid-s9922" xml:space="preserve">2. </s> <s xml:id="echoid-s9923" xml:space="preserve">3. </s> <s xml:id="echoid-s9924" xml:space="preserve">4, dont le côté 2 & </s> <s xml:id="echoid-s9925" xml:space="preserve">3 touchera la circon-<lb/>ference du Cercle, on tirera les lignes E 2 & </s> <s xml:id="echoid-s9926" xml:space="preserve">E 3, & </s> <s xml:id="echoid-s9927" xml:space="preserve">l’on diviſera <lb/>la Baſe 1. </s> <s xml:id="echoid-s9928" xml:space="preserve">4. </s> <s xml:id="echoid-s9929" xml:space="preserve">en 6 parties é©gales, afin d’avoir les points 5. </s> <s xml:id="echoid-s9930" xml:space="preserve">9. </s> <s xml:id="echoid-s9931" xml:space="preserve">12. </s> <s xml:id="echoid-s9932" xml:space="preserve">8. <lb/></s> <s xml:id="echoid-s9933" xml:space="preserve">Après quoi ſur la ligne 5. </s> <s xml:id="echoid-s9934" xml:space="preserve">8. </s> <s xml:id="echoid-s9935" xml:space="preserve">on fera le quarré 5. </s> <s xml:id="echoid-s9936" xml:space="preserve">6. </s> <s xml:id="echoid-s9937" xml:space="preserve">7. </s> <s xml:id="echoid-s9938" xml:space="preserve">8, & </s> <s xml:id="echoid-s9939" xml:space="preserve">ſur la <lb/>ligne 9. </s> <s xml:id="echoid-s9940" xml:space="preserve">12, le quarré 9. </s> <s xml:id="echoid-s9941" xml:space="preserve">10. </s> <s xml:id="echoid-s9942" xml:space="preserve">11. </s> <s xml:id="echoid-s9943" xml:space="preserve">12, alors on aura 3 quarrés par <lb/>conſéquent 12 angles droits qui donneront 12 centres dont nous <lb/>nous ſervirons après avoir prolongé les côtés des quarrés indefi-<lb/>niment dans le ſens qu’on le voit ici.</s> <s xml:id="echoid-s9944" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9945" xml:space="preserve">Pour tracer le contour de la Volute, il faut du centre 1 & </s> <s xml:id="echoid-s9946" xml:space="preserve">de <lb/>l’intervale 1 A, décrire le quart de Cercle AF, du centre 2. </s> <s xml:id="echoid-s9947" xml:space="preserve">& </s> <s xml:id="echoid-s9948" xml:space="preserve">de <lb/>l’intervale 2. </s> <s xml:id="echoid-s9949" xml:space="preserve">F, le quart de Cercle FL, du centre 3 & </s> <s xml:id="echoid-s9950" xml:space="preserve">de l’inter-<lb/>vale 3. </s> <s xml:id="echoid-s9951" xml:space="preserve">L, le quatt de Cercle LO, du centre 4, & </s> <s xml:id="echoid-s9952" xml:space="preserve">de l’intervale <lb/>4. </s> <s xml:id="echoid-s9953" xml:space="preserve">O, le quart de Cercle OQ, du centre 5. </s> <s xml:id="echoid-s9954" xml:space="preserve">& </s> <s xml:id="echoid-s9955" xml:space="preserve">de l’intervale 5. </s> <s xml:id="echoid-s9956" xml:space="preserve">Q, <lb/>le quart de Cercle QG, du centre 6. </s> <s xml:id="echoid-s9957" xml:space="preserve">& </s> <s xml:id="echoid-s9958" xml:space="preserve">de l’intervale 6. </s> <s xml:id="echoid-s9959" xml:space="preserve">G, le quart <lb/>de Cercle GI, du centre 7. </s> <s xml:id="echoid-s9960" xml:space="preserve">& </s> <s xml:id="echoid-s9961" xml:space="preserve">de l’intervale 7. </s> <s xml:id="echoid-s9962" xml:space="preserve">I, le quart de Cer-<lb/>cle IN, du centre 8 & </s> <s xml:id="echoid-s9963" xml:space="preserve">de l’intervale 8. </s> <s xml:id="echoid-s9964" xml:space="preserve">N, le quart de Cercle NR, <lb/>du centre 9. </s> <s xml:id="echoid-s9965" xml:space="preserve">de l’intervale 9. </s> <s xml:id="echoid-s9966" xml:space="preserve">R, le quart de Cercle RH, du cen-<lb/>tre 10. </s> <s xml:id="echoid-s9967" xml:space="preserve">& </s> <s xml:id="echoid-s9968" xml:space="preserve">de l’intervale 10. </s> <s xml:id="echoid-s9969" xml:space="preserve">H, le quart de Cercle HK, du cen-<lb/>tre 11. </s> <s xml:id="echoid-s9970" xml:space="preserve">& </s> <s xml:id="echoid-s9971" xml:space="preserve">de l’intervale 11. </s> <s xml:id="echoid-s9972" xml:space="preserve">K, le quart de Cercle KM; </s> <s xml:id="echoid-s9973" xml:space="preserve">enfin du <pb o="29" file="0473" n="512" rhead="LIVRE V. DE LA DE’CORATION."/> centre 12. </s> <s xml:id="echoid-s9974" xml:space="preserve">& </s> <s xml:id="echoid-s9975" xml:space="preserve">de l’intervale 12. </s> <s xml:id="echoid-s9976" xml:space="preserve">M, l’Arc MS qui aille rencontrer <lb/>la circonference de l’œil de la Volute.</s> <s xml:id="echoid-s9977" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s9978" xml:space="preserve">Pour décrire le contour interieur, il faut prendre la ligne AP, <lb/>égale à une partie de module, enſuite chercher aux lignes CA, CP, <lb/>Ej, une 4<emph style="sub">e</emph> proportionnelle qui ſera aiſée à trouver; </s> <s xml:id="echoid-s9979" xml:space="preserve">car comme la <lb/>ligne CP, eſt les ſept huitiémes de la ligne CA, celle que l’on cher-<lb/>che doit être auſſi les ſept huitiémes de la ligne Ej, afin que les an-<lb/>tecedans ayent même raport à leurs conſéquents. </s> <s xml:id="echoid-s9980" xml:space="preserve">Cela poſé, ſi l’on <lb/>conſidere le quarré 1. </s> <s xml:id="echoid-s9981" xml:space="preserve">2. </s> <s xml:id="echoid-s9982" xml:space="preserve">3. </s> <s xml:id="echoid-s9983" xml:space="preserve">4. </s> <s xml:id="echoid-s9984" xml:space="preserve">de la 4<emph style="sub">e</emph> Figure que j’ai détaché de la <lb/>Volute pour l’exprimer plus en grand, l’on y verra la ligne Ej, qui <lb/>eſt ſupoſée égale aux ſept huitiémes de la ligne E 1. </s> <s xml:id="echoid-s9985" xml:space="preserve">Or ſi de l’autre <lb/>côté du point E, on prend la partie Em, égale à Ej, on aura la ligne <lb/>jm, qu’il faut diviſer en 6 parties égales, comme l’on a fait pour <lb/>la ligne 1. </s> <s xml:id="echoid-s9986" xml:space="preserve">4, & </s> <s xml:id="echoid-s9987" xml:space="preserve">faire ſur les Baſes jm, eh, & </s> <s xml:id="echoid-s9988" xml:space="preserve">ab, les quarrés iklm, <lb/>efgh, acdb, dont les 12 angles droits donneront encore 12 nouveaux <lb/>centres, qui ſerviront à tracer la Volute interieure que l’on voit <lb/>ponctuée ſur la figure. </s> <s xml:id="echoid-s9989" xml:space="preserve">Car ſi l’on ſupoſe pour un inſtant que les <lb/>quarrés, dont je viens de faire mention, ſoient placés ſur le diamêtre <lb/>de l’œil de la Volute, on commencera par décrire un quart de <lb/>Cercle qui aura pour centre le point j, & </s> <s xml:id="echoid-s9990" xml:space="preserve">pour rayon l’intervale <lb/>ip, & </s> <s xml:id="echoid-s9991" xml:space="preserve">alors ce quart de Cercle ira ſe terminer ſur le prolongement <lb/>du côté jk, comme on l’a fait en premier lieu, enſuite du point k, <lb/>qui ſervira de ſecond centre, on décrira un autre quart de Cercle <lb/>quiaura pour rayon l’intervale du point k, à l’endroit où le premier <lb/>quart de Cercle aura été ſe terminer ſur le prolongement de jk, & </s> <s xml:id="echoid-s9992" xml:space="preserve"><lb/>l’on continuera de ſuite à décrire tous lesautres contours de la mê-<lb/>me maniere que l’on a fait pour la premiere Volute, puiſque la <lb/>conſtruction eſt la même: </s> <s xml:id="echoid-s9993" xml:space="preserve">la ſeule difference eſt que les quarrés, qui <lb/>donnent les centres de l’une, ſont plus grands que ceux qui don-<lb/>nent les centres de l’autre; </s> <s xml:id="echoid-s9994" xml:space="preserve">& </s> <s xml:id="echoid-s9995" xml:space="preserve">il ſuffira, pour avoir une parfaite <lb/>intelligence de tout ceci, de prendre un compas & </s> <s xml:id="echoid-s9996" xml:space="preserve">lui faire faire <lb/>tous les mouvemens dont je viens de parler.</s> <s xml:id="echoid-s9997" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div443" type="section" level="1" n="113"> <head xml:id="echoid-head323" xml:space="preserve">CHAPITRE SIXIE’ME.</head> <head xml:id="echoid-head324" style="it" xml:space="preserve">De l’Ordre Corintbien.</head> <p> <s xml:id="echoid-s9998" xml:space="preserve">NOUS mettons ici l’Ordre Corinthien devant le Compoſite, <lb/>comme s’il étoit inferieur à ce dernier; </s> <s xml:id="echoid-s9999" xml:space="preserve">mais, c’eſt pour nous <lb/>conformer à Vignole: </s> <s xml:id="echoid-s10000" xml:space="preserve">autrement il ſeroit plus naturel de mettre <pb o="30" file="0474" n="513" rhead="LA SCIENCE DES INGENIEURS,"/> le Compoſite immédiatement après l’Ionique, comme ont fait Sca-<lb/>mozzy & </s> <s xml:id="echoid-s10001" xml:space="preserve">Mr. </s> <s xml:id="echoid-s10002" xml:space="preserve">de Chambray, qui ont regardé avec raiſon le Corin-<lb/>thien comme le plus parfait & </s> <s xml:id="echoid-s10003" xml:space="preserve">le plus délicat.</s> <s xml:id="echoid-s10004" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10005" xml:space="preserve">Vignole donne 20 modules de hauteur à la Colomne de l’Ordre <lb/>compoſé, en y comprenant ſa Baſe & </s> <s xml:id="echoid-s10006" xml:space="preserve">ſon Chapiteau; </s> <s xml:id="echoid-s10007" xml:space="preserve">il’diviſe encore <lb/>le module en 18 parties comme dans l’Ordre précédent, & </s> <s xml:id="echoid-s10008" xml:space="preserve">ſuit à peu-<lb/>près les mêmes proportions pour l’Entablement & </s> <s xml:id="echoid-s10009" xml:space="preserve">le Piédeſtal; </s> <s xml:id="echoid-s10010" xml:space="preserve">c’eſt-<lb/>à-dire, qu’il donnne à l’entablement 5 modules de hauteur, qui eſt <lb/>préciſement le quart de la Colomne; </s> <s xml:id="echoid-s10011" xml:space="preserve">mais au lieu de prendre le tiers <lb/>de cette même hauteur pour le Piédeſtal qui devroit être ici de 6 <lb/>modules & </s> <s xml:id="echoid-s10012" xml:space="preserve">12 parties, il le fait un tant ſoit peu plus élevé, lui donnant <lb/>7 modules, par conſéquent 6 parties de plus qu’il ne devroit avoir: <lb/></s> <s xml:id="echoid-s10013" xml:space="preserve"> <anchor type="note" xlink:label="note-0474-01a" xlink:href="note-0474-01"/> ſans doute qu’il en a uſé ainſi, pour faire paroître cet Ordre encore <lb/> <anchor type="note" xlink:label="note-0474-02a" xlink:href="note-0474-02"/> plus délicat, & </s> <s xml:id="echoid-s10014" xml:space="preserve">rendre la proportion du Piédeſtal plus agréable, en <lb/>faiſant que la hauteur du Dé ſoit double de ſa largeur, comme on <lb/>le va voir.</s> <s xml:id="echoid-s10015" xml:space="preserve"/> </p> <div xml:id="echoid-div443" type="float" level="2" n="1"> <note position="left" xlink:label="note-0474-01" xlink:href="note-0474-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>40.</note> <note position="left" xlink:label="note-0474-02" xlink:href="note-0474-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> </div> <div xml:id="echoid-div445" type="section" level="1" n="114"> <head xml:id="echoid-head325" style="it" xml:space="preserve">Piédeſtal Corinthien.</head> <p> <s xml:id="echoid-s10016" xml:space="preserve">La hauteur du Piédeſtal ſe faiſant de 7 modules, on donne 22 <lb/>parties pour la Baſe, & </s> <s xml:id="echoid-s10017" xml:space="preserve">14 pour la Corniche, ainſi il reſte 5 modu-<lb/>les 10 parties pour la hauteur du Dé, & </s> <s xml:id="echoid-s10018" xml:space="preserve">comme la largeur du même <lb/>Dé doit être de 2 modules 14 parties pour ſe trouver égale à celle <lb/>de la Plinthe de la Baſe de la Colomne, l’on voit comme je le viens <lb/>de dire que la hauteur du Dé ſe trouve double de ſa largeur.</s> <s xml:id="echoid-s10019" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10020" xml:space="preserve">Des 12 parties qui déterminent la hauteur de la Baſe du Piédeſ-<lb/>tal, on en donne 4 à la Plinthe, 3 au Tore, une à la Regle, 3 à la <lb/>Doucine ou Gueule, & </s> <s xml:id="echoid-s10021" xml:space="preserve">une à l’Aſtragale; </s> <s xml:id="echoid-s10022" xml:space="preserve">& </s> <s xml:id="echoid-s10023" xml:space="preserve">toute la ſaillie eſt de <lb/>8 parties. </s> <s xml:id="echoid-s10024" xml:space="preserve">A l’égard des moulures du Dé, elles ne ſont compoſées <lb/>que de 2 Regles qui ont chacune une partie: </s> <s xml:id="echoid-s10025" xml:space="preserve">de ces deux Regles, <lb/>il y en a une en bas & </s> <s xml:id="echoid-s10026" xml:space="preserve">l’autre en haut; </s> <s xml:id="echoid-s10027" xml:space="preserve">celle d’en bas avec ſon Conge <lb/>fait que la largeur du Dé ſe trouve réduite comme nous l’avons déja <lb/>dit à 2 modules 14 parties.</s> <s xml:id="echoid-s10028" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10029" xml:space="preserve">Des 14 parties que doit avoir la Corniche du Piédeſtal, on en <lb/>donne une à l’Aſtragale, 5 au Gorgerin, une au Filet, une à un autre <lb/>Aſtragale, une à l’Ove, 3 à la Goûtiere, une & </s> <s xml:id="echoid-s10030" xml:space="preserve">un tiers au Talon & </s> <s xml:id="echoid-s10031" xml:space="preserve"><lb/>2 tiers de parties au Filet qui eſt au-deſſus, à l’égard de toute la <lb/>ſaillie, elle eſt de 8 parties comme celle de la baſe.</s> <s xml:id="echoid-s10032" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div446" type="section" level="1" n="115"> <head xml:id="echoid-head326" style="it" xml:space="preserve">Colomne Corinthienne.</head> <p> <s xml:id="echoid-s10033" xml:space="preserve">La hauteur de la Baſe de cette Colomne eſt d’un module, ſes <lb/>moulures ſont la Plinthe qui a 6 parties, le Tore inferieur 4, le Fi- <pb o="31" file="0475" n="514" rhead="LIVRE V. DE LA DE’CORATION."/> let un quart, la Scotie de deſſous une partie & </s> <s xml:id="echoid-s10034" xml:space="preserve">demie, le Filet un <lb/>quart, l’Aſtragale inferieur une demi, l’Aſtragale ſuperieur auſſi une <lb/>demi, le Filet un quart, la Scotie de deſſus une demi, le Filet un <lb/>quart, enfin le Tore ſuperieur eſt de 3 parties; </s> <s xml:id="echoid-s10035" xml:space="preserve">à l’égard de la ſaillie <lb/>de la Baſe, elle eſt de 7 parties, par ce moyen la largeur de la Plin-<lb/>the ſe trouve de 2 modules & </s> <s xml:id="echoid-s10036" xml:space="preserve">14 parties, par conſequent égale à <lb/>celle du Dé du Piédeſtal comme nous l’avons dit ci-devant.</s> <s xml:id="echoid-s10037" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10038" xml:space="preserve">La hauteur du Fuſt de la Colomne eſt de 16 modules 12 parties, <lb/> <anchor type="note" xlink:label="note-0475-01a" xlink:href="note-0475-01"/> ſes moulures ſont l’Orle d’enbas avec ſon Chamfrain qui eſt d’une <lb/> <anchor type="note" xlink:label="note-0475-02a" xlink:href="note-0475-02"/> partie & </s> <s xml:id="echoid-s10039" xml:space="preserve">demi, & </s> <s xml:id="echoid-s10040" xml:space="preserve">l’Orle d’enhaut auſſi avec ſon Chamfrain qui <lb/>n’eſt que d’une partie, & </s> <s xml:id="echoid-s10041" xml:space="preserve">terminé par un Aſtragale qui en a 2.</s> <s xml:id="echoid-s10042" xml:space="preserve"/> </p> <div xml:id="echoid-div446" type="float" level="2" n="1"> <note position="right" xlink:label="note-0475-01" xlink:href="note-0475-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>41.</note> <note position="right" xlink:label="note-0475-02" xlink:href="note-0475-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 4.</note> </div> <p> <s xml:id="echoid-s10043" xml:space="preserve">La largeur de la Colomne par le bas eſt de 2 modules reduite à <lb/>un module 12 parties par le haut, ainſi la diminution eſt de 3 par-<lb/>ties de chaque côté, & </s> <s xml:id="echoid-s10044" xml:space="preserve">afin que l’Aſtragale quitermine la Colomne <lb/>réponde au vif de la même Colomne par le bas, on lui donne 3 <lb/>parties pour ſaillie.</s> <s xml:id="echoid-s10045" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10046" xml:space="preserve">La hauteur du Chapiteau Corinthien ſe fait de 2 modules 6 par-<lb/>ties: </s> <s xml:id="echoid-s10047" xml:space="preserve">on donne 2 modules aux Vaſe, Pannier, ou Tambour, & </s> <s xml:id="echoid-s10048" xml:space="preserve">6 parties à <lb/>l’Abaque, les Feüilles dont le Tambour eſt couvert ont auſſi leurs <lb/>proportions, les plus courtes ont 9 parties de hauteur, depuis leur <lb/>naiſſance juſqu’au ſommet de leur remplis ou courbure, & </s> <s xml:id="echoid-s10049" xml:space="preserve">leurs <lb/>plis en ont 3, les autres Feüilles qui ſont au-deſſus de celle-ci, les <lb/>ſurmontent de 9 parties, c’eſt-à-dire qu’elles en ont 18 de hauteur <lb/>depuis l’Aſtragale, leur reply eſt auſſi de 3 parties, enfin les Feüil-<lb/>les moyennes qui ſortent des tiges qu’on voit poſées dans les inter-<lb/>vales des grandes Feüilles ont 4 parties; </s> <s xml:id="echoid-s10050" xml:space="preserve">l’Orle ou bord du Vaſe a <lb/>pour hauteur 2 parties. </s> <s xml:id="echoid-s10051" xml:space="preserve">Les Volutes qui ſont ſous les angles ou <lb/>corne de l’Abaque ont pour hauteur 8 parties, depuis le deſſous de <lb/>leur enroulement juſqu’au deſſus de l’Orle du Tambour. </s> <s xml:id="echoid-s10052" xml:space="preserve">L’Abaque <lb/>a comme nous l’avons dit pour hauteur 6 parties dont on en donne <lb/>3 à la Plinthe, une à la Regle, & </s> <s xml:id="echoid-s10053" xml:space="preserve">2 à l’Ove, la largeur de la Campane <lb/>ou Tambour eſt la même que celle de la Colomne, & </s> <s xml:id="echoid-s10054" xml:space="preserve">doit être par <lb/>conſéquent d’un module 12 parties, & </s> <s xml:id="echoid-s10055" xml:space="preserve">par le haut de 2 modules 6 <lb/>parties, toute la longueur de la diagonale de l’Abaque eſt de 4 mo-<lb/>dules, la ſaillie de la Plinthe eſt de 4 parties, la Regle en a 2 & </s> <s xml:id="echoid-s10056" xml:space="preserve">de-<lb/>mi de plus; </s> <s xml:id="echoid-s10057" xml:space="preserve">la largeur des cornes de l’Abaque eſt de 4 parties, & </s> <s xml:id="echoid-s10058" xml:space="preserve"><lb/>pour avoir la ſaillie des Volutes & </s> <s xml:id="echoid-s10059" xml:space="preserve">des Feüilles, il faut que les unes <lb/>& </s> <s xml:id="echoid-s10060" xml:space="preserve">les autres aillent ſe terminer ſur la ligne tirée du bout de la cor-<lb/>ne de l’Abaque à l’extrémité de l’Aſtragale qui eſt au ſommet de la <lb/>Colomne: </s> <s xml:id="echoid-s10061" xml:space="preserve">à l’égard de la courbure qui forme l’enfoncement de <lb/>l’Abaque, elle ſe fait par une portion de Cercle qui a pour centre <pb o="32" file="0476" n="515" rhead="LA SCIENCE DES INGENIEURS,"/> l’angle du triangle équilateral, dont la Baſe eſt égale à la diſtance <lb/>du milieu d’une corne de l’Abaque à l’autre.</s> <s xml:id="echoid-s10062" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10063" xml:space="preserve">Les Feüilles de ce Chapiteau ſont toûjours au nombre de 16, <lb/>dont il y en a 8 à chaque rang, chaque Feüille ſe partage en 7 ou <lb/>9 Bouquets, dont on en donne 2, ou pour mieux dire un entier <lb/>& </s> <s xml:id="echoid-s10064" xml:space="preserve">demi de chaque côté pour former le revers, quelquefois ce re-<lb/>vers ſe fait de 3 Bouquets preſque entiers, refendus ſuivant la na-<lb/>ture de la Feüille.</s> <s xml:id="echoid-s10065" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10066" xml:space="preserve">Ces Feüilles ſe font d’Achante, d’Olive, ou de Perſil; </s> <s xml:id="echoid-s10067" xml:space="preserve">mais quand <lb/>l’Ordre Corinthien eſt fort élevé, il vaudroit mieux ſe ſervir des <lb/>Feüilles d’Olives que des autres, parce qu’étant aſſés plates & </s> <s xml:id="echoid-s10068" xml:space="preserve">rece-<lb/>vant mieux la lumiere que celles dont le travail eſt plus déclicat, el-<lb/>les paroiſſent plus diſtinctement étant vûës d’une grande diſtance, <lb/>que les autres qui ne ſont guére propres qu’à être vûës de près.</s> <s xml:id="echoid-s10069" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10070" xml:space="preserve">Quand on fait ces Feüilles, il faut avoir un ſoin tout particulier <lb/>de les deſſiner de bon goût; </s> <s xml:id="echoid-s10071" xml:space="preserve">prendre garde qu’en les refendant par <lb/>Bouquets, les Bouquets ne s’écartent trop, mais que toutes en-<lb/>ſemble forment une ſeule Feüille qui ne devienne pas trop étroite <lb/>vers le haut; </s> <s xml:id="echoid-s10072" xml:space="preserve">que chaque Bouquet tende à trouver ſon origine vers <lb/>le bas de la côte du milieu, autrement les Feüilles n’ont ni graces <lb/>ni beautés.</s> <s xml:id="echoid-s10073" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div448" type="section" level="1" n="116"> <head xml:id="echoid-head327" style="it" xml:space="preserve">Entablement Corinthien.</head> <p> <s xml:id="echoid-s10074" xml:space="preserve">La hauteur de cet Entablement eſt de 5 modules dont on en don-<lb/>ne un & </s> <s xml:id="echoid-s10075" xml:space="preserve">12 parties à l’Architrave, autant à la Friſe, & </s> <s xml:id="echoid-s10076" xml:space="preserve">2 mo-<lb/>dules à la Corniche; </s> <s xml:id="echoid-s10077" xml:space="preserve">les moulures de l’Architrave ſont la Bande <lb/>de deſſous qui a cinq parties, lAſtragale une, la Bande du mi-<lb/>lieu 6, le Talon 2, la Bande de deſſus 7, l’Aſtragale une, la <lb/>Gueule droite 4, & </s> <s xml:id="echoid-s10078" xml:space="preserve">la Regle une; </s> <s xml:id="echoid-s10079" xml:space="preserve">toute la ſaillie de l’Architrave <lb/>eſt de 5 parties, dont on en ôte 3 pour celle de la Gueule droite, <lb/>3 & </s> <s xml:id="echoid-s10080" xml:space="preserve">demi pour celle de la Bande de deſſous, & </s> <s xml:id="echoid-s10081" xml:space="preserve">4 & </s> <s xml:id="echoid-s10082" xml:space="preserve">demi pour <lb/>celle de la Bande du milieu.</s> <s xml:id="echoid-s10083" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10084" xml:space="preserve">La hauteur de la Friſe eſt auſſi d’un module 9 parties, la Bande <lb/>ou aire de la Friſe a un module 7 parties & </s> <s xml:id="echoid-s10085" xml:space="preserve">demi, le Fruit avec ſon <lb/>Conge a une demi partie, & </s> <s xml:id="echoid-s10086" xml:space="preserve">l’Aſtragale en a une entiere, la ſaillie <lb/>de cet Aſtragale eſt de 2 parties.</s> <s xml:id="echoid-s10087" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10088" xml:space="preserve">Les moulures de la Corniche ſont la Gueule droite qui a 3 par-<lb/>ties, le Filet ſous les Denticules une demi partie, la Bande des Den-<lb/>ticules 6, le filet au-deſſus une demi, l’Aſtragale une partie, l’Ove <lb/>4, la Regle ſous les modillons une demi partie, la Bande où ſont <lb/>les modillons 6 parties, le Talon un & </s> <s xml:id="echoid-s10089" xml:space="preserve">demi, la Goûtiere 5, le <pb o="33" file="0477" n="516" rhead="LIVRE V. DE LA DE’CORATION."/> Talon qui eſt enſuite un & </s> <s xml:id="echoid-s10090" xml:space="preserve">demi, le Filet un demi, la Doucine <lb/>qui eſt au-deſſus 5 parties, & </s> <s xml:id="echoid-s10091" xml:space="preserve">enfin la Regle qui termine letouten a <lb/>une; </s> <s xml:id="echoid-s10092" xml:space="preserve">la ſaillie de toute la Corniche eſt de 2 modules 2 parties, on <lb/>donne 5 parties pour celle de la Regle, & </s> <s xml:id="echoid-s10093" xml:space="preserve">de celle-ci il en faut ôter <lb/>une & </s> <s xml:id="echoid-s10094" xml:space="preserve">demi pour avoir celle des modillons, le Filet ſous les mo-<lb/>dillons en a 17 & </s> <s xml:id="echoid-s10095" xml:space="preserve">demi, deſquels on en retranche 4 & </s> <s xml:id="echoid-s10096" xml:space="preserve">demi pour <lb/>celle des Denticules, la longueur ou portée des Modillons eſt de <lb/>16 parties, leur largeur eſt de 8, & </s> <s xml:id="echoid-s10097" xml:space="preserve">leur entre-deux de 16, la largeur <lb/>de chaque Denticule eſt de 4, & </s> <s xml:id="echoid-s10098" xml:space="preserve">leur intervale de 2 parties.</s> <s xml:id="echoid-s10099" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10100" xml:space="preserve">Les ornemens particuliers des Talons ſe font avec des Feüilles de <lb/>Chêne, ou avec des Arceaux entrelaſſés de Feüilles & </s> <s xml:id="echoid-s10101" xml:space="preserve">de Fleurs, <lb/>ceux des Aſtragales ſe font avec des Olives mêlées de Grains de <lb/>Patenotes ou Grains de Lauriers, à l’égard des œufs qui ſe taillent <lb/>ſur l’Ove, ils doivent répondre à plomb ſur le milieu des Denticu-<lb/>les; </s> <s xml:id="echoid-s10102" xml:space="preserve">on taille auſſi des muffles ou têtes de Lyon dans la Doucine <lb/>qui doivent répondre au milieu de chaque Modillon.</s> <s xml:id="echoid-s10103" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10104" xml:space="preserve">J’ajoûterai qu’il eſt à propos que les Feüilles des Modillons <lb/>ſoient de la nature de celles qui font l’ornement du Chapiteau plû-<lb/>tôt que de toute autre eſpece.</s> <s xml:id="echoid-s10105" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div449" type="section" level="1" n="117"> <head xml:id="echoid-head328" xml:space="preserve">CHAPITRE SEPTIE’ME.</head> <head xml:id="echoid-head329" style="it" xml:space="preserve">De l’Ordre Compoſite.</head> <p> <s xml:id="echoid-s10106" xml:space="preserve">IL y a aparence que les anciens Architectes n’ont eû aucunes Re-<lb/>gles déterminées pour l’Ordre Compoſite. </s> <s xml:id="echoid-s10107" xml:space="preserve">Vitruve, après avoir <lb/>expliquéles meſures du Corinthien, dit à la fin du premier Chapitre <lb/>de ſon quatriéme Livre, qu’il y a d’autres ſortes de Chapiteaux de <lb/>differens noms, que l’on met ſur les mêmes Colomnes, mais dont il <lb/>ne peut marquer les proportions, ni leur donner le nom d’un Or-<lb/>dre, parce qu’étant pris du Dorique, Ionique, & </s> <s xml:id="echoid-s10108" xml:space="preserve">Corinthien, on en <lb/>a changé les moulures pour en faire d’autres nouvelles. </s> <s xml:id="echoid-s10109" xml:space="preserve">Ce ſont à <lb/>peu-près ſes termes; </s> <s xml:id="echoid-s10110" xml:space="preserve">d’où l’on peut conclure, que dans le tems que <lb/>cet Auteur a écrit, l’Ordre Compoſite n’étoit pas ſeparé des autres, <lb/>mais dépendoit du goût & </s> <s xml:id="echoid-s10111" xml:space="preserve">du caprice de ceux qui ne voulant pas <lb/>imiter exactement les trois Ordres Grecs ſe donnoient la liberté d’y <lb/>faire tous les changemens que pouvoit fournir leur imagination; <lb/></s> <s xml:id="echoid-s10112" xml:space="preserve">ainſi, les Architectes modernes ont crû ne pouvoir mieux faire <lb/>pour établir quelque choſe de certain pour l’Ordre Compoſite, que <pb o="34" file="0478" n="517" rhead="LA SCIENCE DES INGENIEURS,"/> de meſurer exactement quelques-uns des plus beaux Ouvrages de <lb/>l’Antiquité quinous ſont reſtés dans ce goût-la, & </s> <s xml:id="echoid-s10113" xml:space="preserve">s’en ſervir comme <lb/>de modeles & </s> <s xml:id="echoid-s10114" xml:space="preserve">de regles aſſurées pour en déterminer les proportions, <lb/>s’attachant d’ailleurs à lui donner les membres & </s> <s xml:id="echoid-s10115" xml:space="preserve">les moulures les <lb/>plus delicates & </s> <s xml:id="echoid-s10116" xml:space="preserve">les ornemens les plus recherchés.</s> <s xml:id="echoid-s10117" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10118" xml:space="preserve">Vignole ne met point de difference entre les meſures generales <lb/>de cet Ordre & </s> <s xml:id="echoid-s10119" xml:space="preserve">celles du Corinthien, donnant encore 20 modules <lb/>de hauteur à la Colomne Compoſite, y compris ſa Baſe & </s> <s xml:id="echoid-s10120" xml:space="preserve">ſon Cha-<lb/>piteau, 7 au Piédeſtal qui eſt un peu plus du tiers de la Colomne <lb/>pour les raiſons que l’on a vû ci-devant, & </s> <s xml:id="echoid-s10121" xml:space="preserve">5 à l’Entablement qui <lb/>eſt toûjours du quart dela Colomne: </s> <s xml:id="echoid-s10122" xml:space="preserve">ainſi, ce n’eſt que dans les <lb/>meſures particulieres des moulures, & </s> <s xml:id="echoid-s10123" xml:space="preserve">dans la figure du Chapiteau, <lb/>que cet Ordre differe du Corinthien.</s> <s xml:id="echoid-s10124" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div450" type="section" level="1" n="118"> <head xml:id="echoid-head330" style="it" xml:space="preserve">Piédeſtal Compoſite.</head> <p> <s xml:id="echoid-s10125" xml:space="preserve">La Baſe du Piédeſtal eſt de 12 parties, ſur quoi l’on en donne 4 <lb/> <anchor type="note" xlink:label="note-0478-01a" xlink:href="note-0478-01"/> à la Plinthe, 3 au Tore, une à la Regle, 3 au Talon renverſé, & </s> <s xml:id="echoid-s10126" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0478-02a" xlink:href="note-0478-02"/> une au Cordon; </s> <s xml:id="echoid-s10127" xml:space="preserve">toute la ſaillie eſt de 8 parties.</s> <s xml:id="echoid-s10128" xml:space="preserve"/> </p> <div xml:id="echoid-div450" type="float" level="2" n="1"> <note position="left" xlink:label="note-0478-01" xlink:href="note-0478-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>40.</note> <note position="left" xlink:label="note-0478-02" xlink:href="note-0478-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 5.</note> </div> <p> <s xml:id="echoid-s10129" xml:space="preserve">La hauteur du Tronc du Piédeſtal eſt de 5 modules 10 parties, & </s> <s xml:id="echoid-s10130" xml:space="preserve"><lb/>ſa largeur de 2 modules 14 parties, ſes moulures ſont la Regle in-<lb/>ferieure & </s> <s xml:id="echoid-s10131" xml:space="preserve">ſuperieure avec leurs Chanfrains, qui ont chacun une <lb/>partie.</s> <s xml:id="echoid-s10132" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10133" xml:space="preserve">La hauteur de la Corniche du Piédeſtal eſt de 14 parties, ſur quoi <lb/>l’on en donne une à l’Aſtragale, 5 au Gorgerin ou à la Friſe, une <lb/>au demi-creux, deux tiers au Filet, une & </s> <s xml:id="echoid-s10134" xml:space="preserve">un tiers à la Doucine, 3 <lb/>parties à la Goûtiere, une & </s> <s xml:id="echoid-s10135" xml:space="preserve">demi au Talon, & </s> <s xml:id="echoid-s10136" xml:space="preserve">deux tiers à la Re-<lb/>gle; </s> <s xml:id="echoid-s10137" xml:space="preserve">quant à la ſaillie elle eſt égale à celle de la Baſe, c’eſt-à-dire, <lb/>qu’elle eſt de 8 parties, le ſoffite de la Goûtiere eſt creuſé par-deſ-<lb/>ſous d’un Canal qui laiſſe en dehors une Bande d’une partie.</s> <s xml:id="echoid-s10138" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10139" xml:space="preserve">Il y a des Architectes qui mettent des Tables en ſaillie ou en <lb/>creux dans le Dé de ce Piédeſtal, ſans conſiderer le caractere de <lb/>l’Ordre. </s> <s xml:id="echoid-s10140" xml:space="preserve">Ces Tables à la verité font un fort bel effet: </s> <s xml:id="echoid-s10141" xml:space="preserve">mais, il faut <lb/>prendre garde qu’elles ne doivent avoir de ſaillie qu’aux Ordres <lb/>Toſcan & </s> <s xml:id="echoid-s10142" xml:space="preserve">Dorique; </s> <s xml:id="echoid-s10143" xml:space="preserve">car aux 3 autres Ordres elles doivent être <lb/>priſes en dedans. </s> <s xml:id="echoid-s10144" xml:space="preserve">Il eſt vrai, que les Anciens n’ont pas pratiqué ces <lb/>eſpeces d’ornemens aux Piédeſtaux, ayant toûjours laiſſé nud les <lb/>faces du Dé, parce qu’aparament ils aprehendoient que cela fût <lb/>contraire à la ſolidité.</s> <s xml:id="echoid-s10145" xml:space="preserve"/> </p> <pb o="35" file="0479" n="518" rhead="LIVRE V. DE LA DE’CORATION."/> </div> <div xml:id="echoid-div452" type="section" level="1" n="119"> <head xml:id="echoid-head331" style="it" xml:space="preserve">Colomne Compoſite.</head> <p> <s xml:id="echoid-s10146" xml:space="preserve">La Baſe de la Colomne eſt encore d’un module ou de 18 parties, <lb/>ſur quoi l’on en donne 6 à la Plinthe, 4 au Tore inferieur, un quart <lb/>au Filet, 2 parties à la Scotie inferieure, un quart au Filet, 3 parties <lb/>au Tore ſuperieur, un demi à l’Aſtragale, un quart au Filet, un & </s> <s xml:id="echoid-s10147" xml:space="preserve"><lb/>demi à la Scotie ſuperieure, un quart au Filet, & </s> <s xml:id="echoid-s10148" xml:space="preserve">3 parties au Tore <lb/>ſuperieur; </s> <s xml:id="echoid-s10149" xml:space="preserve">la ſaillie eſt de 7 parties de chaque côté, & </s> <s xml:id="echoid-s10150" xml:space="preserve">ainſi la Plin-<lb/>the en front eſt de 2 modules 14 parties, il en faut ôter 3 parties <lb/>3 quarts pour la ſaillie du Tore ſuperieur, pour celle de l’Aſtragale <lb/>4 & </s> <s xml:id="echoid-s10151" xml:space="preserve">demi, & </s> <s xml:id="echoid-s10152" xml:space="preserve">5 pour celle du Filet.</s> <s xml:id="echoid-s10153" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10154" xml:space="preserve">Le Fuſt de la Colomne a pour hauteur 16 modules 12 parties, <lb/>ſes moulures ſont l’Orle inferieur avec ſon Chanfrain qui a une <lb/>partie & </s> <s xml:id="echoid-s10155" xml:space="preserve">demi, le Tronc a 16 modules 7 parties & </s> <s xml:id="echoid-s10156" xml:space="preserve">demi, l’Orle <lb/>ſuperieur avec ſon Chanfrain une partie, & </s> <s xml:id="echoid-s10157" xml:space="preserve">l’Aſtragale 2, la groſ-<lb/>ſeur du pied de la Colomne eſt de 2 modules, & </s> <s xml:id="echoid-s10158" xml:space="preserve">réduite par le <lb/>haut à un module 12 parties, ainſi la diminution eſt de 3 parties <lb/>de chaque côté: </s> <s xml:id="echoid-s10159" xml:space="preserve">la ſaillie de l’Orle inferieur eſt de 2 parties, celle <lb/>du ſuperieur d’un & </s> <s xml:id="echoid-s10160" xml:space="preserve">demi, & </s> <s xml:id="echoid-s10161" xml:space="preserve">celle de l’Aſtragale de 3, afin qu’il <lb/>réponde au vif de la Colomne.</s> <s xml:id="echoid-s10162" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10163" xml:space="preserve">La hauteur du Chapiteau eſt de 2 modules 6 parties comme au <lb/> <anchor type="note" xlink:label="note-0479-01a" xlink:href="note-0479-01"/> Corinthien, le Tambour a 2 modules, & </s> <s xml:id="echoid-s10164" xml:space="preserve">l’Abaque 6 parties, les <lb/> <anchor type="note" xlink:label="note-0479-02a" xlink:href="note-0479-02"/> membres du Tambour ſont les Feüilles baſſes qui ont 9 parties, <lb/>leur repli 3, les Feuilles hautes 9, leur repli 3, l’eſpace des Ro-<lb/>ſetes 4, l’Orle un’demi, l’Aſtragale un & </s> <s xml:id="echoid-s10165" xml:space="preserve">demi, l’Ove 4 parties, <lb/>l’Orle de la Campane 2; </s> <s xml:id="echoid-s10166" xml:space="preserve">les membres de l’Abaque ſont la Plinthe <lb/>ou Goutiere qui a 4 parties, le Filet une demi, l’Ove une & </s> <s xml:id="echoid-s10167" xml:space="preserve">demi, <lb/>la hauteur des Volutes 16 parties, depuis le haut des Feuilles juſ-<lb/>qu’au Filet de l’Abaque; </s> <s xml:id="echoid-s10168" xml:space="preserve">les ſaillies dépendent du Plan & </s> <s xml:id="echoid-s10169" xml:space="preserve">du Profil <lb/>ſur la diagonale comme au Corinthien, ſur lequel il faut tirer une <lb/>ligne du coin de l’Ove de l’Abaque juſqu’à l’Aſtragale du Fuſt de <lb/>la Colomne qui déterminera celle des Feuilles, & </s> <s xml:id="echoid-s10170" xml:space="preserve">ſi l’on tire une <lb/>ligne parallele aux moulures de l’Abaque par le point où la ligne de <lb/>la hauteur de la Volute eſt diviſée, enſorte qu’elle laiſſe 9 parties <lb/>au-deſſus & </s> <s xml:id="echoid-s10171" xml:space="preserve">7 au-deſſous, & </s> <s xml:id="echoid-s10172" xml:space="preserve">qu’on prenne ſur cette ligne en dedans 8 <lb/>parties, à commencer du point où elle coupe celle qui détermine <lb/>les ſaillies, l’on aurale centre de l’œil de la Voulute qui ſe décrira com-<lb/>me l’Ionique, avec cette difference ſeulement que les Ioniques <lb/>ſont droites ou plattes ſur les deux faces anterieures ou poſterieu-<lb/>res du Chapiteau, au lieu que celles-ci ſuivent le contour du ren- <pb o="36" file="0480" n="519" rhead="LA SCIENCE DES INGENIEURS,"/> foncement des 4 faces du Chapiteau. </s> <s xml:id="echoid-s10173" xml:space="preserve">A l’égard de la ſtructure du <lb/>plan & </s> <s xml:id="echoid-s10174" xml:space="preserve">du contour du renfoncement de l’Abaque, c’eſt la même <lb/>choſe qu’au Corinthien, la ſaillie de l’Ove ſur le vif du haut de la <lb/>Colomne a 6 parties, celle de l’Aſtragale 3, & </s> <s xml:id="echoid-s10175" xml:space="preserve">celle de l’Orle 1 <lb/>& </s> <s xml:id="echoid-s10176" xml:space="preserve">demi: </s> <s xml:id="echoid-s10177" xml:space="preserve">le front des cornes de l’Abaque eſt de 6 parties, ſa largeur <lb/>diagonale eſt de 4 modules, dont on ôte 4 parties de chaque côté <lb/>pour la goutiere de l’Abaque, & </s> <s xml:id="echoid-s10178" xml:space="preserve">2 & </s> <s xml:id="echoid-s10179" xml:space="preserve">demi pour le Filet, la largeur <lb/>de la fleur du milieu eſt de 8 parties.</s> <s xml:id="echoid-s10180" xml:space="preserve"/> </p> <div xml:id="echoid-div452" type="float" level="2" n="1"> <note position="right" xlink:label="note-0479-01" xlink:href="note-0479-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>41.</note> <note position="right" xlink:label="note-0479-02" xlink:href="note-0479-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 5.</note> </div> </div> <div xml:id="echoid-div454" type="section" level="1" n="120"> <head xml:id="echoid-head332" style="it" xml:space="preserve">Entablement Compoſite.</head> <p> <s xml:id="echoid-s10181" xml:space="preserve">L’Architrave a 1 module 9 parties, ſur quoi l’on en donne 8 à <lb/>la premiere Bande, 2 au Talon, 10 à la ſeconde Bande, 1 à l’Aſ-<lb/>tragle, 3 à l’Ove, 2 au Demi-Creux, & </s> <s xml:id="echoid-s10182" xml:space="preserve">une à la Regle: </s> <s xml:id="echoid-s10183" xml:space="preserve">la ſaillie <lb/>a 7 parties, dont l’on ôte 2 pour le pied du Demi-Creux, & </s> <s xml:id="echoid-s10184" xml:space="preserve">5 <lb/>pour la ſeconde Bande.</s> <s xml:id="echoid-s10185" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10186" xml:space="preserve">La Friſe a auſſi 1 module 9 parties, ſur quoi l’on en donne 1 & </s> <s xml:id="echoid-s10187" xml:space="preserve"><lb/>demi au Filet avec ſon Chanfrain, & </s> <s xml:id="echoid-s10188" xml:space="preserve">1 au Cordon ou Aſtragale.</s> <s xml:id="echoid-s10189" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10190" xml:space="preserve">La Corniche a 2 modules ou 36 parties, dont l’on donne 5 <lb/>à l’Ove, 1 à la Regle ſous les Denticules, 8 à la Bande des Denti-<lb/>cules, 4 au Talon, 1 à la Regle, 1 & </s> <s xml:id="echoid-s10191" xml:space="preserve">demi à l’Ove, 5 à la Gou-<lb/>tiere, 1 à l’Aſtragale, 2 au Talon, 1 à la Regle, 5 à la Doucine, & </s> <s xml:id="echoid-s10192" xml:space="preserve"><lb/>1 & </s> <s xml:id="echoid-s10193" xml:space="preserve">demi à la Regle; </s> <s xml:id="echoid-s10194" xml:space="preserve">la ſaillie eſt égale à la hauteur, c’eſt-à-dire a <lb/>2 modules, dont il faut ôter 5 parties pour celle de la Regle, & </s> <s xml:id="echoid-s10195" xml:space="preserve">8 <lb/>pour la Goutiere, & </s> <s xml:id="echoid-s10196" xml:space="preserve">de celle-ci 10 pour celle de la Regle, la ſaillie <lb/>de la Bande des Denticules eſt de 14 parties, celle de la Regle ſous <lb/>les Denticules 8, & </s> <s xml:id="echoid-s10197" xml:space="preserve">celle du pied de l’Ove 2. </s> <s xml:id="echoid-s10198" xml:space="preserve">Sous le ſoffite de la <lb/>Goutierre on entaille un Canal, dont le contour doit ſuivre agrea-<lb/>blement celui de l’Ove de deſſous, & </s> <s xml:id="echoid-s10199" xml:space="preserve">laiſſe une Bande en dehors <lb/>de la largeur de deux parties, le front des Denticules eſt de 6 par-<lb/>ties, & </s> <s xml:id="echoid-s10200" xml:space="preserve">leur intervale de 3; </s> <s xml:id="echoid-s10201" xml:space="preserve">dans le fond des intervales on laiſſe une <lb/>Regle ſous le Talon, creuſée à la moitié & </s> <s xml:id="echoid-s10202" xml:space="preserve">ſoutenuë de deux pe-<lb/>tits ronds.</s> <s xml:id="echoid-s10203" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10204" xml:space="preserve">L’on fait auſſi des canelures aux Colomnes Corinthiennes & </s> <s xml:id="echoid-s10205" xml:space="preserve">Com-<lb/>poſites, de la façon que nous avons dit qu’on le pratiquoit à l’Io-<lb/>nique, c’eſt-à-dire qu’elles doivent être au nombre de 24 & </s> <s xml:id="echoid-s10206" xml:space="preserve">tracées <lb/>de même: </s> <s xml:id="echoid-s10207" xml:space="preserve">on taille quelquefois dans ces canelures, pour rendre leurs <lb/>côtes moins fragiles & </s> <s xml:id="echoid-s10208" xml:space="preserve">moins ſujettes à être briſées, certains orne-<lb/>mens qu’on nomme Rudentures, qui ont la figure de cordes ou de ba-<lb/>tons; </s> <s xml:id="echoid-s10209" xml:space="preserve">par exemple, quand on fait des Colomnes ou des Pilaſtres ca-<lb/>nelées ſans piédeſtaux & </s> <s xml:id="echoid-s10210" xml:space="preserve">poſées à crû ſur le rez-de-Chauſſée, ou du <pb file="0481" n="520"/> <pb file="0481a" n="521"/> <anchor type="figure" xlink:label="fig-0481a-01a" xlink:href="fig-0481a-01"/> <pb file="0482" n="522"/> <pb file="0483" n="523"/> <pb file="0483a" n="524"/> <anchor type="figure" xlink:label="fig-0483a-01a" xlink:href="fig-0483a-01"/> <pb file="0484" n="525"/> <pb o="37" file="0485" n="526" rhead="LIVRE V. DE LA DE’CORATION."/> moins ſi peu élevées qu’on les peut toucher de la main, il faut ru-<lb/>denter les canelures juſqu’au tiers de leur hauteur, c’eſt-à-dire qu’il <lb/>faut les remplir en partie juſqu’à cette hauteur de ces Rudentures, <lb/>afin d’en fortifier les côtes qui autrement ſeroient bien-tôt ruinées.</s> <s xml:id="echoid-s10211" xml:space="preserve"/> </p> <div xml:id="echoid-div454" type="float" level="2" n="1"> <figure xlink:label="fig-0481a-01" xlink:href="fig-0481a-01a"> <image file="0481a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0481a-01"/> </figure> <figure xlink:label="fig-0483a-01" xlink:href="fig-0483a-01a"> <image file="0483a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0483a-01"/> </figure> </div> <p> <s xml:id="echoid-s10212" xml:space="preserve">Ces Rudentures, qui furent d’abord imaginées pour l’utilité, ont <lb/>donné enſuite occaſion d’en faire des ornemens pour enrichir les <lb/>canelures: </s> <s xml:id="echoid-s10213" xml:space="preserve">ainſi au lieu de ces Rudentures fortes & </s> <s xml:id="echoid-s10214" xml:space="preserve">ſimples, on en <lb/>fait quelquefois de très legeres, on les travaille en figures de ru-<lb/>bans tortillés, de feüillages, de chapelets, de fleurons & </s> <s xml:id="echoid-s10215" xml:space="preserve">autres or-<lb/>nemens délicats & </s> <s xml:id="echoid-s10216" xml:space="preserve">fort riches; </s> <s xml:id="echoid-s10217" xml:space="preserve">mais, cesſortes de Rudentures ne doi-<lb/>vent être pratiquées que dans des Colomnes ou des Pilaſtres de <lb/>Marbre, & </s> <s xml:id="echoid-s10218" xml:space="preserve">qui ſont hors la portée des mains du public.</s> <s xml:id="echoid-s10219" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10220" xml:space="preserve">Il faut que le nombre des canelures ſoit moindre, lorſqu’on y <lb/>taille de ces ornemens pour les degager davantage, enſorte qu’au <lb/>lieu de 24 qui ſont ordinairement au Corinthien, il n’y en ait que <lb/>20, & </s> <s xml:id="echoid-s10221" xml:space="preserve">même que chaque côté n’ait environ que le quart de la lar-<lb/>geur de la canelure. </s> <s xml:id="echoid-s10222" xml:space="preserve">On diſpoſe ces ornemens de differentes manie-<lb/>res, où les faiſant ſortir du Roſeau de la longueur du tiers du Fuſt <lb/>comme aux Colomnes Ioniques des Thuileries, ce qui eſt la meil-<lb/>leure maniere, en les eſpaçant ſans Roſeaux, comme lorſqu’il n’y <lb/>a dans chaque Canelure qu’une branche au bas, une autre au tiers <lb/>ou à la moitié, & </s> <s xml:id="echoid-s10223" xml:space="preserve">une troiſiéme au haut, ou enfin par petits bouquets <lb/>mêlez alternativement dans les canelures.</s> <s xml:id="echoid-s10224" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div456" type="section" level="1" n="121"> <head xml:id="echoid-head333" style="it" xml:space="preserve">Remarques ſur les cinq Ordres en général, ſuivies de l’Ex-<lb/>plication de quelques Fragmens des plus beaux Ediſices <lb/>antiques de Rome.</head> <p> <s xml:id="echoid-s10225" xml:space="preserve">Si l’on en veut croire Mr. </s> <s xml:id="echoid-s10226" xml:space="preserve">de Chambrai, l’Orde Toſcan ne doit être <lb/>employé qu’aux Maiſons de Campagne, c’eſt-à-dire aux lieux ruſti-<lb/>ques & </s> <s xml:id="echoid-s10227" xml:space="preserve">champêtres: </s> <s xml:id="echoid-s10228" xml:space="preserve">il eſt vrai que de la maniere dont Vitruve, <lb/>Palladio, & </s> <s xml:id="echoid-s10229" xml:space="preserve">quelques autres l’ont traité, il n’a rien de recommanda-<lb/>ble; </s> <s xml:id="echoid-s10230" xml:space="preserve">mais il faut convenir, que, ſuivant la Compoſition de Vignole, <lb/>il a dans ſa ſimplicité des beautez qui le rendent très eſtimable.</s> <s xml:id="echoid-s10231" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10232" xml:space="preserve">L’Ordre Dorique peut paſſer pour le premier que les Grecs ont <lb/>inventé, ſa compoſition eſt grande & </s> <s xml:id="echoid-s10233" xml:space="preserve">noble, les Trigliphes qui font <lb/>l’ornement de la Friſe ont quelque choſe de gracieux & </s> <s xml:id="echoid-s10234" xml:space="preserve">de fier; <lb/></s> <s xml:id="echoid-s10235" xml:space="preserve">dans les plus anciens Monumens qu’on a fait de cet Ordre, les Co-<lb/>lomnes y étoient ſans baſe, & </s> <s xml:id="echoid-s10236" xml:space="preserve">on eſt aſſés embarraſſé d’en donner <lb/>une raiſon ſatisfaiſante. </s> <s xml:id="echoid-s10237" xml:space="preserve">Vitruve veut qu’étant compoſèes à l’imita-<lb/>tion d’un homme nud, fort & </s> <s xml:id="echoid-s10238" xml:space="preserve">nerveux, tel que ſeroit un Hercule, <pb o="38" file="0486" n="527" rhead="LA SCIENCE DES INGENIEURS,"/> elles ne doivent point avoir de baſe, voulant qu’une baſe ſoit à la <lb/>Colomne ce qu’une chauſſure eſt à l’homme; </s> <s xml:id="echoid-s10239" xml:space="preserve">mais, j’avouë que je ne <lb/>puis conſiderer une Colomne ſans baſe, en la comparant à un hom-<lb/>me, qu’en même-tems je n’aye l’idée d’un homme ſans pieds, plû-<lb/>tôt que ſans chauſſure: </s> <s xml:id="echoid-s10240" xml:space="preserve">ainſi, j’aime mieux croire que les premiers <lb/>Architectes ne s’étoient pas encore aviſez de donner des baſes à leurs <lb/>Colomnes, lorſqu’ils imaginerent cet Ordre.</s> <s xml:id="echoid-s10241" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10242" xml:space="preserve">Vitruve prétend, que les Colomnes de l’Ordre Ionique ont été <lb/>compoſées ſur le modéle d’une jeune fille coëffée en cheveux, & </s> <s xml:id="echoid-s10243" xml:space="preserve"><lb/>d’une taille gracieuſe: </s> <s xml:id="echoid-s10244" xml:space="preserve">les Romains les employoient particuliere-<lb/>ment aux Temples, & </s> <s xml:id="echoid-s10245" xml:space="preserve">aux endroits où l’on rendoit la Juſtice. </s> <s xml:id="echoid-s10246" xml:space="preserve">A l’é-<lb/>gard de la baſe que Vignole leur donne, elle paroît de mauvais goût, <lb/>le gros Tore qui la termine faiſant un vilain effet ſur les Aſtragales <lb/>& </s> <s xml:id="echoid-s10247" xml:space="preserve">les Cavets qui ſont au-deſſous: </s> <s xml:id="echoid-s10248" xml:space="preserve">les Anciens y mettoient ordinai-<lb/>rement une baſe attique, ſemblable à celle qui eſt repreſentée par <lb/>la 7<emph style="sub">e</emph> figure de la Planche 40. </s> <s xml:id="echoid-s10249" xml:space="preserve">Comme on peut s’en ſervir indiffe-<lb/> <anchor type="note" xlink:label="note-0486-01a" xlink:href="note-0486-01"/> remment dans les trois derniers Ordres, & </s> <s xml:id="echoid-s10250" xml:space="preserve">qu’elle eſt plus belle que <lb/> <anchor type="note" xlink:label="note-0486-02a" xlink:href="note-0486-02"/> toutes celles de Vignole, je vais en donner les proportions, afin <lb/>que dans l’occaſion on puiſſe en faire uſage.</s> <s xml:id="echoid-s10251" xml:space="preserve"/> </p> <div xml:id="echoid-div456" type="float" level="2" n="1"> <note position="left" xlink:label="note-0486-01" xlink:href="note-0486-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>40.</note> <note position="left" xlink:label="note-0486-02" xlink:href="note-0486-02a" xml:space="preserve"><emph style="sc">Fig</emph>. 7.</note> </div> <p> <s xml:id="echoid-s10252" xml:space="preserve">La hauteur de cette baſe eſt d’un module comme à l’ordinaire, <lb/>ſes moulures ſont la Plinthe qui a 6 parties, le Tore inferieur 4 & </s> <s xml:id="echoid-s10253" xml:space="preserve"><lb/>demi, l’Orle inferieur un demi, la Scotie 3 parties, l’Orle ſuperieur <lb/>un demi, & </s> <s xml:id="echoid-s10254" xml:space="preserve">le Tore ſuperieur 3 & </s> <s xml:id="echoid-s10255" xml:space="preserve">demi, toute la ſaillie eſt de 7 par-<lb/>ties, dont on en donne 2 tiers pour celle du Tore ſuperieur, 4 & </s> <s xml:id="echoid-s10256" xml:space="preserve"><lb/>demi pour celle de l’Orle qui eſt au-deſſous, & </s> <s xml:id="echoid-s10257" xml:space="preserve">6 pour le Creux <lb/>de la Scotie.</s> <s xml:id="echoid-s10258" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10259" xml:space="preserve">La figure 6<emph style="sub">e</emph> repreſente encore une autre baſe de fort bon goût, <lb/>qui eſt un peu plus ornée que l’autre, mais cependant ſans confu-<lb/>ſion, elle eſt compoſée de la Plinthe qui a 6 parties, du Tore in-<lb/>ferieur qui en a 3 & </s> <s xml:id="echoid-s10260" xml:space="preserve">demi, d’un Aſtragale qui en a 1, d’un Filet qui <lb/>n’a qu’une demie, d’une Scotie qui en a 2 & </s> <s xml:id="echoid-s10261" xml:space="preserve">demi, au-deſſous de <lb/>laquelle eſt un Filet de demie partie, un Aſtragale de 1 partie, le <lb/>tout terminé par un Tore qui en a 3, les ſaillies ſont les mêmes <lb/>que les précedentes.</s> <s xml:id="echoid-s10262" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10263" xml:space="preserve">L’Ordre Corinthien eſt le plus noble, le plus riche, & </s> <s xml:id="echoid-s10264" xml:space="preserve">le plus dé-<lb/>licat de tous ceux qui ont été imaginés par les Anciens & </s> <s xml:id="echoid-s10265" xml:space="preserve">les Mo-<lb/>dernes, (car les Modernes ont auſſi voulu inventer un Ordre, mais <lb/>avec peu de ſuccès.) </s> <s xml:id="echoid-s10266" xml:space="preserve">Les proportions que lui donne Vignole me pa-<lb/>roiſſent fort belles: </s> <s xml:id="echoid-s10267" xml:space="preserve">on lui reproche ſeulement d’avoir mis dans la <lb/>Corniche de l’Entablement des Denticules avec des Modillons; </s> <s xml:id="echoid-s10268" xml:space="preserve">par-<lb/>ceque, dit-on, cela eſt contraire à la Regle preſcrite par Vitruve, qui <pb o="39" file="0487" n="528" rhead="LIVRE V. DE LA DE’CORATION."/> les condamne, & </s> <s xml:id="echoid-s10269" xml:space="preserve">qui ne veut de Denticules qu’aux Ordres Dori-<lb/>que & </s> <s xml:id="echoid-s10270" xml:space="preserve">Ionique. </s> <s xml:id="echoid-s10271" xml:space="preserve">Cependant, il ſemble que les meilleurs Architectes <lb/>de notre tems ne ſe ſont pas arrêtés au ſentiment de Vitruve, puiſ-<lb/>qu’ils en ont mis dans tous les autres Ordres, excepté au Toſcan; </s> <s xml:id="echoid-s10272" xml:space="preserve">& </s> <s xml:id="echoid-s10273" xml:space="preserve"><lb/>je ne vois pas qu’on puiſſe leur en faire un crime, puiſqu’elles pro-<lb/>duiſent un fort bel effet: </s> <s xml:id="echoid-s10274" xml:space="preserve">mais il y a des gens qui ont un reſpect <lb/>ſuperſticieux pour tout ce qui vient des Anciens, & </s> <s xml:id="echoid-s10275" xml:space="preserve">dont la pré-<lb/>vention eſt ſi grande, que les meilleures raiſons ne ſont pas capa-<lb/>bles de les deſabuſer.</s> <s xml:id="echoid-s10276" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10277" xml:space="preserve">Vitruve raporte un trait aſſés ſingulier au ſujet de l’Invention de <lb/>cet Ordre: </s> <s xml:id="echoid-s10278" xml:space="preserve">il dit qu’une jeune Fille de Corinthe étant morte, ſa <lb/>nourrice mit ſur ſon tombeau un Panier dans lequel étoient quel-<lb/>ques petits Vaſes qu’elle avoit aimés pendant ſa vie; </s> <s xml:id="echoid-s10279" xml:space="preserve">&</s> <s xml:id="echoid-s10280" xml:space="preserve">, pour em-<lb/>pêcher que la pluye ne les gâtât, elle mit une Thuile ſur le Panier, <lb/>qui par haſard ayant été poſé ſur une racine d’Acanthe, il arriva <lb/>qu’au Printems les Feüilles venant à pouſſer au tour du Pannier ſe <lb/>recourberent ſous les coins de la Thuile où elles formerent une <lb/>maniere de Volute, & </s> <s xml:id="echoid-s10281" xml:space="preserve">quele Sculpteur Callimachus s’étant apperçû <lb/>de l’effet ſingulier & </s> <s xml:id="echoid-s10282" xml:space="preserve">gracieux que produiſoient ces Feüilles ainſi <lb/>diſpoſées profita de l’idée que lui fournit la Nature pour en com-<lb/>poſer le Chapiteau qu’on a depuis nommé Corinthien.</s> <s xml:id="echoid-s10283" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10284" xml:space="preserve">Je n’ai rien à dire de particulier ſur l’Ordre Compoſite, en ayant <lb/>aſſés fait mention dans les Chapitres précédens: </s> <s xml:id="echoid-s10285" xml:space="preserve">j’ajoûterai ſeule-<lb/>ment qu’on n’approuve point que Vignole ait donné la même pro-<lb/>portion à la Colomne de cet Ordre, qu’à celle du Corinthien, puiſ-<lb/>que naturellement il devoit avoir égard à la difference de leurs <lb/>Chapiteaux; </s> <s xml:id="echoid-s10286" xml:space="preserve">on lui reproche auſſi d’avoir fait les Entablemens de <lb/>ces deux derniers Ordres trop lourds, & </s> <s xml:id="echoid-s10287" xml:space="preserve">d’y avoir employé des <lb/>Denticules plus groſſieres que dans le Dorique, puiſqu’il ſemble <lb/>qu’il auroit dû faire tout le contraire.</s> <s xml:id="echoid-s10288" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10289" xml:space="preserve">Si les Ordres d’Architecture avoient eû des beautés poſitives & </s> <s xml:id="echoid-s10290" xml:space="preserve"><lb/>bien connuës, comme l’a voulu inſinuer Mr. </s> <s xml:id="echoid-s10291" xml:space="preserve">Perrault dans la Pré-<lb/>face de ſon Livre de l’Ordonnance des cinq eſpeces de Colomnes ſelon la <lb/>Méthode des Anciens, les Architectes auroient été obligés de conve-<lb/>nir entr’eux de leurs regles; </s> <s xml:id="echoid-s10292" xml:space="preserve">mais, ces beautés n’étant qu’arbitraires, <lb/>puiſqu’elles ne ſont fondées ſur aucune démonſtration conſtante, <lb/>ceux qui en ont traité nous ont donné des principes bien oppoſés <lb/>ſuivant leur goût & </s> <s xml:id="echoid-s10293" xml:space="preserve">leur genie. </s> <s xml:id="echoid-s10294" xml:space="preserve">Cependant, quoiqu’un même Ordre <lb/>puiſſe avoir des beautés & </s> <s xml:id="echoid-s10295" xml:space="preserve">des proportions différentes, on convient <lb/>qu’il eſt conſtant qu’entre ces diverſes beautés & </s> <s xml:id="echoid-s10296" xml:space="preserve">proportions il y en <lb/>a qui plaiſent davantage, & </s> <s xml:id="echoid-s10297" xml:space="preserve">qui ſont plus univerſellement aprouvées;</s> <s xml:id="echoid-s10298" xml:space="preserve"> <pb o="40" file="0488" n="529" rhead="LA SCIENCE DES INGENIEURS,"/> & </s> <s xml:id="echoid-s10299" xml:space="preserve">c’eſt ce que l’on peut dire des Ordres de Palladio & </s> <s xml:id="echoid-s10300" xml:space="preserve">de Vignole. <lb/></s> <s xml:id="echoid-s10301" xml:space="preserve">Et pour qu’on en puiſſe faire le Paralelle, il eſt bon qu’on ſoit pré-<lb/>venu que les cinq Ordres qui ſontſur les Planches 37. </s> <s xml:id="echoid-s10302" xml:space="preserve">38. </s> <s xml:id="echoid-s10303" xml:space="preserve">& </s> <s xml:id="echoid-s10304" xml:space="preserve">39. </s> <s xml:id="echoid-s10305" xml:space="preserve">ſont <lb/>ceux de Palladio, que je ne m’arreterai point à détailler, pour ne <lb/>pas groſſir ce Livre mal-à-propos: </s> <s xml:id="echoid-s10306" xml:space="preserve">il ſuffira ſeulement, qu’en con-<lb/>ſiderant avec attention les deſſeins de cet Auteur, on ſe mette en <lb/>état de juger en voyant un Edifice s’il eſt décoré ſelon lui ou Vi-<lb/>gnole; </s> <s xml:id="echoid-s10307" xml:space="preserve">car, il eſt bien aiſé de ne pas prendre le change, la compoſi-<lb/>tion de ce dernier étant beaucoup plus grande & </s> <s xml:id="echoid-s10308" xml:space="preserve">plus majeſtueuſe.</s> <s xml:id="echoid-s10309" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10310" xml:space="preserve">Pour faire voir que c’eſt avec juſtice que j’ai donné, dans le com-<lb/>mencement de ce cinquiéme Livre, tant d’Eloge à l’Architecture <lb/>ancienne, je vais expliquer quelques Fragmens des plus beaux Edi-<lb/>fices de Rome, que j’ai tiré du Paralelle de l’Architecture antique avec <lb/>la moderne de Mr. </s> <s xml:id="echoid-s10311" xml:space="preserve">de Chambray, qui peut paſſer ſans contredit pour <lb/>un des grands hommes de ſon tems, & </s> <s xml:id="echoid-s10312" xml:space="preserve">le plus habile Architecte <lb/>que nous ayons eû en France: </s> <s xml:id="echoid-s10313" xml:space="preserve">l’honneur qu’il fait à la Nation mé-<lb/>rite bien que je m’arrête un moment pour rapporter quelques traits <lb/>de ſon Hiſtoire; </s> <s xml:id="echoid-s10314" xml:space="preserve">les habiles gens m’en ſauront gré, & </s> <s xml:id="echoid-s10315" xml:space="preserve">je m’acqui-<lb/>terai en partie de la reconnoiſſance que je dois à ſa mémoire pour <lb/>les lumieres que j’ai tirées de la lecture de ſes Ouvrages.</s> <s xml:id="echoid-s10316" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10317" xml:space="preserve">Rollant Freart de Chambray, Couſin germain de Mr. </s> <s xml:id="echoid-s10318" xml:space="preserve">Deſnoyers, Se-<lb/>cretaire d’Etat de la Guerre & </s> <s xml:id="echoid-s10319" xml:space="preserve">Surintendant des Bâtimens ſous Loüis <lb/>XIII. </s> <s xml:id="echoid-s10320" xml:space="preserve">fut envoyé à Rome par Ordre de Sa Majeſté en 1640, pour <lb/>négocier des Affaires importantes avec Sa Sainteté. </s> <s xml:id="echoid-s10321" xml:space="preserve">Ce fut dans ce <lb/>Voyage, qu’aidé de Mr. </s> <s xml:id="echoid-s10322" xml:space="preserve">de Chantelou ſon frere, & </s> <s xml:id="echoid-s10323" xml:space="preserve">de Mr. </s> <s xml:id="echoid-s10324" xml:space="preserve">Pouſſin le <lb/>Raphaël de ſon ſiécle, il recueillit ce que l’Italie pouvoit offrir de <lb/>plus rare & </s> <s xml:id="echoid-s10325" xml:space="preserve">de plus curieux. </s> <s xml:id="echoid-s10326" xml:space="preserve">De retour en France, on le députa une <lb/>ſeconde fois pour faire benir deux Couronnes de Diamans que leurs <lb/>Majeſtés offroient à N. </s> <s xml:id="echoid-s10327" xml:space="preserve">Dame de Lorette en action de grace de la <lb/>naiſſance du Dauphin, c’eſt-à-dire de Loüis le Grand; </s> <s xml:id="echoid-s10328" xml:space="preserve">& </s> <s xml:id="echoid-s10329" xml:space="preserve">comme le <lb/>Roy avoit été fort ſatisfait des ſavantes Recherches de ſon premier <lb/>Voyage, il luiordonna d’en faire de nouvelles, & </s> <s xml:id="echoid-s10330" xml:space="preserve">de nerien négliger <lb/>pour tout ce qui pouvoit contribuer à la perfection de l’Architec-<lb/>ture, & </s> <s xml:id="echoid-s10331" xml:space="preserve">à la beauté du Louvre que l’on bâtiſſoit alors. </s> <s xml:id="echoid-s10332" xml:space="preserve">C’eſt à ces <lb/>deux Voyages, que nous devons en partie ſon excellent Livre du <lb/>Paralelle.</s> <s xml:id="echoid-s10333" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10334" xml:space="preserve">Louïs XIV, voulant faire continuer le Bâtiment du Louvre, en-<lb/>gagea par ſon Ambaſſadeur à Rome le Cavalier Bernin, Architecte <lb/>fameux, de venir en France: </s> <s xml:id="echoid-s10335" xml:space="preserve">il n’y fut pas plûtôt arrivé, que Mr. </s> <s xml:id="echoid-s10336" xml:space="preserve">de <lb/>Chambray eût ordre de travailler de concert avec lui; </s> <s xml:id="echoid-s10337" xml:space="preserve">mais, l’Italien <lb/>ne fut pas longtems ſans connoître combien les connoiſſances de <pb file="0489" n="530"/> <pb file="0489a" n="531"/> <anchor type="figure" xlink:label="fig-0489a-01a" xlink:href="fig-0489a-01"/> <pb file="0490" n="532"/> <pb o="41" file="0491" n="533" rhead="LIVRE V. DE LA DE’CORATION."/> Mr. </s> <s xml:id="echoid-s10338" xml:space="preserve">de Chambray étoient ſuperieures aux ſiennes; </s> <s xml:id="echoid-s10339" xml:space="preserve">& </s> <s xml:id="echoid-s10340" xml:space="preserve">ce quieſt éga-<lb/>lement à la louange de tous deux, c’eſt que le Cavalier Bernin dit <lb/>au Roi, que Sa Majeſté auroit pû ſe diſpenſer de le faire venir de ſi <lb/>loin, puiſqu’il avoit trouvé dans Mr. </s> <s xml:id="echoid-s10341" xml:space="preserve">de Chambray un Maître qu’il <lb/>ſe feroit honneur de ſuivre, & </s> <s xml:id="echoid-s10342" xml:space="preserve">qu’il n’étoit pas aſſés temeraire pour <lb/>rien changer à ſon projet. </s> <s xml:id="echoid-s10343" xml:space="preserve">Exemple rare, où la concurrence s’eſt <lb/>dépoüillée de ſes propres interets pour rendre hommage au vrai <lb/>mérite; </s> <s xml:id="echoid-s10344" xml:space="preserve">mais, cela ne doit pas ſurprendre: </s> <s xml:id="echoid-s10345" xml:space="preserve">les grands Hommes ont <lb/>toûjours des traits qui marquent leur caractere, au lieu que l’igno-<lb/>rance croit ſe ſignaler, & </s> <s xml:id="echoid-s10346" xml:space="preserve">trouver de la reſſource, dans les ſentimens <lb/>de jalouſie qu’elle fait éclater.</s> <s xml:id="echoid-s10347" xml:space="preserve"/> </p> <div xml:id="echoid-div457" type="float" level="2" n="2"> <figure xlink:label="fig-0489a-01" xlink:href="fig-0489a-01a"> <image file="0489a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0489a-01"/> </figure> </div> <p> <s xml:id="echoid-s10348" xml:space="preserve">Comme il ne reſte aucun ancien Monument de l’Ordre Toſcan <lb/>qui ſe ſoit trouvé digne de quelque attention, Mr. </s> <s xml:id="echoid-s10349" xml:space="preserve">de Chambray <lb/>n’en donne point d’exemple; </s> <s xml:id="echoid-s10350" xml:space="preserve">mais, en récompenſe, on a lieu d’être <lb/>ſatisfait de ceux qu’il raporte des autres Ordres: </s> <s xml:id="echoid-s10351" xml:space="preserve">& </s> <s xml:id="echoid-s10352" xml:space="preserve">comme, tout ad-<lb/>mirables qu’ils ſont, on ne peut les regarder ſans faire quelque <lb/>choix, puiſqu’il ſe trouve de chaque Ordre en particulier des Pro-<lb/>fils mieux proportionnés les uns que les autres, je me ſuis attaché <lb/>à décrire les plus aprouvés dans le rang qui leur convenoit relati-<lb/>vement à celui que Vignole donne aux ſiens.</s> <s xml:id="echoid-s10353" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10354" xml:space="preserve">Si l’on conſidere la Planche 43. </s> <s xml:id="echoid-s10355" xml:space="preserve">l’on verra qu’elle repreſente un <lb/> <anchor type="note" xlink:label="note-0491-01a" xlink:href="note-0491-01"/> Chapiteau & </s> <s xml:id="echoid-s10356" xml:space="preserve">un Entablement Dorique tirés des Termes de Diocle-<lb/>tien. </s> <s xml:id="echoid-s10357" xml:space="preserve">Ce morceau eſt regardé comme un des plus excellens de tous <lb/>les ouvrages antiques de cet Ordre, ſa compoſition eſt noble & </s> <s xml:id="echoid-s10358" xml:space="preserve"><lb/>réguliere, les ornemens ſont apliqués avec goût ſur chaque mem-<lb/>bre, en enrichiſſant les uns ſans bleſſer les autres.</s> <s xml:id="echoid-s10359" xml:space="preserve"/> </p> <div xml:id="echoid-div458" type="float" level="2" n="3"> <note position="right" xlink:label="note-0491-01" xlink:href="note-0491-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>43.</note> </div> <p> <s xml:id="echoid-s10360" xml:space="preserve">Comme la Colomne ne ſubſiſte plus en entier, on ne peut juger <lb/>poſitivement des proportions generales qu’on y a ſuivi: </s> <s xml:id="echoid-s10361" xml:space="preserve">cependant, <lb/>l’on remarque que l’entablement eſt de 4 modules; </s> <s xml:id="echoid-s10362" xml:space="preserve">ce qui fait pré-<lb/>ſumer que la Colomne en avoit 16, parceque les Anciens ont preſ-<lb/>que toûjours donné à la hauteur de l’Entablement le quart de la <lb/>Colomne: </s> <s xml:id="echoid-s10363" xml:space="preserve">quant à ſa Baſe, Mr. </s> <s xml:id="echoid-s10364" xml:space="preserve">de Chambray ne la raporte point, <lb/>parce qu’aparamment il n’en paroit plus, la barbarie de certains <lb/>ſiécles ayant tellement défiguré la plupart des anciens Monumens, <lb/>que ce n’eſt qu’avec bien de la peine qu’on en a tiré quelque mor-<lb/>ceau entier.</s> <s xml:id="echoid-s10365" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10366" xml:space="preserve">La 44<emph style="sub">e</emph>. </s> <s xml:id="echoid-s10367" xml:space="preserve">Planche repréſente un Profil Ionique qui peut paſſer pour <lb/> <anchor type="note" xlink:label="note-0491-02a" xlink:href="note-0491-02"/> l’ouvrage le plus parfait qui nous ſoit reſté des Anciens. </s> <s xml:id="echoid-s10368" xml:space="preserve">Mr. </s> <s xml:id="echoid-s10369" xml:space="preserve">de Cham-<lb/>bray le regarde comme le Chef-d’œuvre de la plus haute Perfec-<lb/>tion. </s> <s xml:id="echoid-s10370" xml:space="preserve">Palladio, qui l’a auſſi raporté dans le treiziéme Chapitre de <lb/>ſon quatriéme Livre, ne peut lui donner trop d’éloge; </s> <s xml:id="echoid-s10371" xml:space="preserve">& </s> <s xml:id="echoid-s10372" xml:space="preserve">quand on <pb o="42" file="0492" n="534" rhead="LA SCIENCE DES INGENIEURS,"/> manqueroit de goût pour en connoître toute la beauté, il ſuffiroit <lb/>du Jugement de ces deux grands Maîtres pour en ſentir le prix.</s> <s xml:id="echoid-s10373" xml:space="preserve"/> </p> <div xml:id="echoid-div459" type="float" level="2" n="4"> <note position="right" xlink:label="note-0491-02" xlink:href="note-0491-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>44.</note> </div> <p> <s xml:id="echoid-s10374" xml:space="preserve">L’Ordre entier, depuis le rez-de-Chauſſée juſqu’à la Corniche, a <lb/>pour hauteur 11 diamêtres ou 22 modules, la Colomne avec ſa <lb/>Baſe & </s> <s xml:id="echoid-s10375" xml:space="preserve">ſon Chapiteau en a 18, & </s> <s xml:id="echoid-s10376" xml:space="preserve">l’Entablement c’eſt-à-dire l’Ar-<lb/>chitrave, la Friſe, & </s> <s xml:id="echoid-s10377" xml:space="preserve">la Corniche en a 4, qui eſt un peu moins du <lb/>quart de la Colomne. </s> <s xml:id="echoid-s10378" xml:space="preserve">Si l’on veut juger de la proportion des autres <lb/>parties, on n’aura qu’à conſiderer les chiſſres qui ſont cottés à l’en-<lb/>droit de chaque membre: </s> <s xml:id="echoid-s10379" xml:space="preserve">ſurquoi il eſt à propos que j’avertiſſe <lb/>que Mr. </s> <s xml:id="echoid-s10380" xml:space="preserve">de Chambray diviſe le module en 30 parties égales qu’il <lb/>nomme minutes.</s> <s xml:id="echoid-s10381" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10382" xml:space="preserve">La Planche 45 comprend un Profil Corinthien ſi riche & </s> <s xml:id="echoid-s10383" xml:space="preserve">ſi ſu-<lb/> <anchor type="note" xlink:label="note-0492-01a" xlink:href="note-0492-01"/> perbe, qu’il ne paroit pas qu’on puiſſe rien faire de plus magnifique <lb/>que ce qu’on voit dans cet exemple, qu’on ne peut imiter à pro-<lb/>pos, dit Mr. </s> <s xml:id="echoid-s10384" xml:space="preserve">de Chambray, qu’avec beaucoup de prudence & </s> <s xml:id="echoid-s10385" xml:space="preserve">de cir-<lb/>conſpection; </s> <s xml:id="echoid-s10386" xml:space="preserve">car l’abondance des ornemens eſt ſujette à embroüil-<lb/>ler s’ils ne ſont employés avec œconomie, autrement ils font naître <lb/>une confuſion qui bleſſe l’œil des connoiſſeurs; </s> <s xml:id="echoid-s10387" xml:space="preserve">& </s> <s xml:id="echoid-s10388" xml:space="preserve">c’eſt en effet ce <lb/>que j’ai remarqué à Paris à quelque Portail d’Egliſe que l’on a gâté <lb/>en le chargeant d’ornemens ſuperflus: </s> <s xml:id="echoid-s10389" xml:space="preserve">je croi qu’on ſentira bien, <lb/>que je ne veux point parler de celui de St. </s> <s xml:id="echoid-s10390" xml:space="preserve">Gervais, qui peut paſſer <lb/>pour le morceau d’Architecture le plus accompli que nous ayons <lb/>en France.</s> <s xml:id="echoid-s10391" xml:space="preserve"/> </p> <div xml:id="echoid-div460" type="float" level="2" n="5"> <note position="left" xlink:label="note-0492-01" xlink:href="note-0492-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>45.</note> </div> <p> <s xml:id="echoid-s10392" xml:space="preserve">Pour expliquer les proportions generales du profil dont il eſt <lb/>queſtion preſentement, l’on ſaura que la Colomne avec ſa Baſe & </s> <s xml:id="echoid-s10393" xml:space="preserve"><lb/>ſon Chapiteau a 20 modules, que l’Entablement a deux neuviémes <lb/>de la hauteur de la Colomne, ſur quoi l’Architrave & </s> <s xml:id="echoid-s10394" xml:space="preserve">la Friſe ont <lb/>chacun un module & </s> <s xml:id="echoid-s10395" xml:space="preserve">un tiers, c’eſt-à-dire 40 minutes, & </s> <s xml:id="echoid-s10396" xml:space="preserve">la Cor-<lb/>niche deux modules moins 8 minutes, c’eſt-à-dire 52 minutes.</s> <s xml:id="echoid-s10397" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10398" xml:space="preserve">Quant à la Baſe de la Colomne, elle me paroit de fort bon goût, <lb/>étant compoſée de pluſieurs moulures qui font enſemble un tout <lb/>qui réüſſit fort bien.</s> <s xml:id="echoid-s10399" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10400" xml:space="preserve">La Planche 46. </s> <s xml:id="echoid-s10401" xml:space="preserve">comprend encore un’autre Profil Corinthien, <lb/> <anchor type="note" xlink:label="note-0492-02a" xlink:href="note-0492-02"/> qu’on a compoſé ſur l’idée que pluſieurs Hiſtoriens célébres don-<lb/>nent de quelque partie du Temple de Salomon; </s> <s xml:id="echoid-s10402" xml:space="preserve">& </s> <s xml:id="echoid-s10403" xml:space="preserve">comme il me <lb/>ſiéroit mal d’entrer dans aucune Diſſertation critique ſur un Sujet ſi <lb/>équivoque, je prens le parti de raporter à la lettre ce qu’en dit Mr. <lb/></s> <s xml:id="echoid-s10404" xml:space="preserve">de Chambray, & </s> <s xml:id="echoid-s10405" xml:space="preserve">je laiſſe au Lecteur éclairé d’en porter le juge-<lb/>ment qu’il jugera à propos.</s> <s xml:id="echoid-s10406" xml:space="preserve"/> </p> <div xml:id="echoid-div461" type="float" level="2" n="6"> <note position="left" xlink:label="note-0492-02" xlink:href="note-0492-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>46.</note> </div> <p> <s xml:id="echoid-s10407" xml:space="preserve">Voici, dit-il, un Ordre particulier, mais d’une excellente Com-<lb/>poſition: </s> <s xml:id="echoid-s10408" xml:space="preserve">&</s> <s xml:id="echoid-s10409" xml:space="preserve">, quoique je n’oſe pas aſſurer que ce Profil ſoit préci- <pb o="43" file="0493" n="535" rhead="LIVRE V. DE LA DE’CORATION."/> ſément le même que celui du Temple de Salomon (qui eſt le Mo-<lb/>dele que je me ſuis propoſé) neanmoins, autant qu’on peut apro-<lb/>cher de cette divine Idée par la Deſcription qui en paroit dans la <lb/>Bible, & </s> <s xml:id="echoid-s10410" xml:space="preserve">en quelques Hiſtoriens célébres que Vilalpandus raporte <lb/>en ſon grand Ouvrage, où les ornemens & </s> <s xml:id="echoid-s10411" xml:space="preserve">toutes les principales <lb/>proportions de chaque membre ſont exactement ſpecifiés; </s> <s xml:id="echoid-s10412" xml:space="preserve">je crois <lb/>qu’il lui eſt aſſés conforme. </s> <s xml:id="echoid-s10413" xml:space="preserve">La Compoſition en eſt toute Corin-<lb/>thienne, quoique les Feüillages du Chapiteau & </s> <s xml:id="echoid-s10414" xml:space="preserve">ſes Caulicoles <lb/>ſoient de Palmes, & </s> <s xml:id="echoid-s10415" xml:space="preserve">que la Friſe de l’Entablement ait emprunté <lb/>l’Ornement Dorique quiſont des Trigliphes, la Solidité deſquels <lb/>n’a pas beaucoup de conformité avec la Délicateſſe Corinthienne. <lb/></s> <s xml:id="echoid-s10416" xml:space="preserve">Mais, quelque Nom qu’on veüille donner à cet Ordre, neanmoins <lb/>Joſephe dit que c’étoit le Corinthien. </s> <s xml:id="echoid-s10417" xml:space="preserve">Il eſt aſſuré, qu’il n’y en a <lb/>jamais eû de plus parfait: </s> <s xml:id="echoid-s10418" xml:space="preserve">&</s> <s xml:id="echoid-s10419" xml:space="preserve">, bien que le Corinthien ſoit un Or-<lb/>dre tendre & </s> <s xml:id="echoid-s10420" xml:space="preserve">virginal, lequel ne demande pas cette Fermeté & </s> <s xml:id="echoid-s10421" xml:space="preserve">Vi-<lb/>rilité Dorique qui nous eſt ſymboliſée par les Trigliphes, ſi eſt-ce <lb/>qu’on peut en certaines occaſions l’y introduire avec tant d’a-<lb/>dreſſe & </s> <s xml:id="echoid-s10422" xml:space="preserve">de raiſon, qu’elle ſera non-ſeulement excuſable, mais <lb/>très-judicieuſe.</s> </p> <p> <s xml:id="echoid-s10423" xml:space="preserve">L’Ordre Compoſite étant celui qui ſouſſre le plus de difficulté <lb/> <anchor type="note" xlink:label="note-0493-01a" xlink:href="note-0493-01"/> dans l’execution, à cauſe de l’incertitude des proportions que lui ont <lb/>donné les Anciens, je croi qu’on ſera bien aiſe d’en voir un exemple <lb/>ſur la Planche 47. </s> <s xml:id="echoid-s10424" xml:space="preserve">qui repreſente un Profil tiré de l’Arc de Titus à Ro-<lb/>me. </s> <s xml:id="echoid-s10425" xml:space="preserve">Comme cet Arc de Triomphe fut élevé à la gloire de Titus au re-<lb/>tour de la Conquête de Jeruſalem, Mr. </s> <s xml:id="echoid-s10426" xml:space="preserve">de Chambray croit que <lb/>l’Architecte qui le conſtruiſit y avoit ſuivi cet Empereur, où, ſelon <lb/>toute aparence, il étudia les Beautés du Temple, ayant introduit <lb/>dans les Ornemens de la Friſe ſes principales Dépoüilles, comme le <lb/>Chandelier à ſept branches qui étoit dans le Sanctuaire, la Table <lb/>d’Or qui ſervoit à mettre le Pain de Propoſition, & </s> <s xml:id="echoid-s10427" xml:space="preserve">pluſieurs autres <lb/>choſes touchant les Sacrifices, qui ſe voyent encore aujourd’hui. </s> <s xml:id="echoid-s10428" xml:space="preserve">Il <lb/>ajoûte, que cet Arc eſt le premier & </s> <s xml:id="echoid-s10429" xml:space="preserve">le plus achevé qui ait été éle-<lb/>vé à la Gloire des Héros.</s> <s xml:id="echoid-s10430" xml:space="preserve"/> </p> <div xml:id="echoid-div462" type="float" level="2" n="7"> <note position="right" xlink:label="note-0493-01" xlink:href="note-0493-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>47.</note> </div> <figure> <image file="0493-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0493-01"/> </figure> <pb o="44" file="0494" n="536" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div464" type="section" level="1" n="122"> <head xml:id="echoid-head334" xml:space="preserve">CHAPITRE HUITIE’ME.</head> <head xml:id="echoid-head335" style="it" xml:space="preserve">Des Colomnes & de leur Diminution, des Perſiques, & des <lb/>Cariatides.</head> <p> <s xml:id="echoid-s10431" xml:space="preserve">SI l’on juge de l’origine des’Colomnes par ce qu’en diſent quel-<lb/>ques Hiſtoriens, il y a apparence qu’elles ſont trés anciennes, <lb/>& </s> <s xml:id="echoid-s10432" xml:space="preserve">que l’uſage en étoit frequent long-tems avant l’Invention des Or-<lb/>dres. </s> <s xml:id="echoid-s10433" xml:space="preserve">On les fit ſervir d’abord de Monumens pour éterniſer la memoi-<lb/>re des grands hommes, ou pour marquer à la poſterité la reconnoiſ-<lb/>ſance des bienfaits qu’on en avoit reçûs: </s> <s xml:id="echoid-s10434" xml:space="preserve">après leur mort, on dreſ-<lb/>ſoit une Colomne, au ſommet de laquelle étoit l’Urne qui renfer-<lb/>moit leurs cendres, & </s> <s xml:id="echoid-s10435" xml:space="preserve">il y a apparence que c’eſt cette Urne qui a <lb/>donné lieu au Chapiteau dont on s’eſt ſervi depuis pour les cou-<lb/>ronner agreablement.</s> <s xml:id="echoid-s10436" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10437" xml:space="preserve">Vitruve dit que les premieres Colomnes, qui parurent en Grece, <lb/>furent celles du Temple de Junon dans Argos; </s> <s xml:id="echoid-s10438" xml:space="preserve">& </s> <s xml:id="echoid-s10439" xml:space="preserve">que les Doriens, <lb/>ne ſachant quelle proportion leur donner, conſidererent que le pied <lb/>de l’homme étoit ordinairement la ſixiéme partie de ſa hauteur, & </s> <s xml:id="echoid-s10440" xml:space="preserve"><lb/>ſur cet exemple ils firent les Colomnes ſextuples de leur groſſeur: </s> <s xml:id="echoid-s10441" xml:space="preserve">en-<lb/>ſuite, ils en augmenterent la hauteur au Temple de Diane à Epheſe, <lb/>parce qu’ils voulurent leur donner des meſures proportionnées à <lb/>la ſtature des femmes de leur Païs. </s> <s xml:id="echoid-s10442" xml:space="preserve">Quoiqu’il en ſoit, les Architec-<lb/>tes ont toûjours paru fort partagez ſur la hauteur qu’il falloit leur <lb/>donner pour chaque Ordre: </s> <s xml:id="echoid-s10443" xml:space="preserve">c’eſt pourquoi, nous nous en tiendrons <lb/>aux proportions de Vignole, ſans nous arrêter à raporter tout <lb/>ce qu’on pourroit dire ſur ce ſujet.</s> <s xml:id="echoid-s10444" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10445" xml:space="preserve">Les premiers Architectes ayant fait les Colomnes à l’imita-<lb/>tion des arbres, qui ſont ordinairement plus gros par le pied que <lb/>vers le haut, ils les ont auſſi diminuées dans le même goût: </s> <s xml:id="echoid-s10446" xml:space="preserve">mais, <lb/>comme l’on s’eſt aperçu que cette diminution produiſoit un effet <lb/>deſagreable, on s’eſt contenté de ne la commencer qu’au tiers de <lb/>la tige; </s> <s xml:id="echoid-s10447" xml:space="preserve">c’eſt-à-dire, qu’ayant diviſé la hauteur de la tige en trois <lb/>parties égales, la premiere reſte a plomb & </s> <s xml:id="echoid-s10448" xml:space="preserve">partfaitement cilindri-<lb/>que, & </s> <s xml:id="echoid-s10449" xml:space="preserve">les deux autres vont en diminuant imperceptiblement juſ-<lb/>qu’à l’Aſtragale: </s> <s xml:id="echoid-s10450" xml:space="preserve">cette diminution ſe fait plus ou moins ſenſible, <lb/>ſelon la groſſeur ou la delicateſſe des Colomnes, & </s> <s xml:id="echoid-s10451" xml:space="preserve">c’eſt ce que l’on <lb/>a dû remarquer dans les Chapitres precedens.</s> <s xml:id="echoid-s10452" xml:space="preserve"/> </p> <pb file="0495" n="537"/> <pb file="0495a" n="538"/> <figure> <image file="0495a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0495a-01"/> </figure> <pb file="0496" n="539"/> <pb file="0497" n="540"/> <pb file="0497a" n="541"/> <figure> <image file="0497a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0497a-01"/> </figure> <pb file="0498" n="542"/> <pb file="0499" n="543"/> <pb file="0499a" n="544"/> <figure> <image file="0499a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0499a-01"/> </figure> <pb file="0500" n="545"/> <pb file="0501" n="546"/> <pb file="0501a" n="547"/> <figure> <image file="0501a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0501a-01"/> </figure> <pb file="0502" n="548"/> <pb file="0503" n="549"/> <pb file="0503a" n="550"/> <figure> <image file="0503a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0503a-01"/> </figure> <pb file="0504" n="551"/> <pb o="45" file="0505" n="552" rhead="LIVRE V. DE LA DE’CORATION."/> <p> <s xml:id="echoid-s10453" xml:space="preserve">On a auſſi donné du renflement aux Colomnes à l’imitation du <lb/>corps humain, qui eſt plus large vers le milieu que vers les extré-<lb/>mitez: </s> <s xml:id="echoid-s10454" xml:space="preserve">mais, les Architectes ſont encore partagez ſur ce ſujet, parce <lb/>qu’on n’en a point d’exemple antique; </s> <s xml:id="echoid-s10455" xml:space="preserve">il y en a même, qui traitent <lb/>ce renflement d’abus inſuportable: </s> <s xml:id="echoid-s10456" xml:space="preserve">cependant, l’uſage de renfler les <lb/>Colomnes à leurs tiers eſt ſi pratiqué par les modernes, qu’on n’en <lb/>voit preſque point quine le ſoient: </s> <s xml:id="echoid-s10457" xml:space="preserve">c’eſt pourquoi on a cherché plu-<lb/>ſieurs moyens pour le faire agreablement; </s> <s xml:id="echoid-s10458" xml:space="preserve">car, moins il eſt ſenſible, <lb/>& </s> <s xml:id="echoid-s10459" xml:space="preserve">plus il eſt beau. </s> <s xml:id="echoid-s10460" xml:space="preserve">Or, pour ſavoir de quelle maniere on doit les <lb/>diminuer ou les renfler, voici les deux Pratiques que donne Vigno-<lb/>le, que je raporterai preferablement à pluſieurs autres qui ſont à la <lb/>verité moins mécaniques, mais plus difficiles à executer.</s> <s xml:id="echoid-s10461" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div465" type="section" level="1" n="123"> <head xml:id="echoid-head336" style="it" xml:space="preserve">Maniere de diminuer les Colomnes.</head> <p> <s xml:id="echoid-s10462" xml:space="preserve">Après avoir déterminé la hauteur & </s> <s xml:id="echoid-s10463" xml:space="preserve">la groſſeur des Colomnes, <lb/> <anchor type="note" xlink:label="note-0505-01a" xlink:href="note-0505-01"/> avec la quantité dont on veut qu’elle diminue depuis le tiers juſ-<lb/>qu’au haut, il faut d’écrire un demi-cercle ſur le diamêtre CD, en-<lb/>ſuite mener la parallele GE à l’Axe AB, enſorte qu’elle vienne ren-<lb/>contrer le demi-cercle au point E, afin d’avoir l’arc CE: </s> <s xml:id="echoid-s10464" xml:space="preserve">l’on divi-<lb/>ſera enſuite la ligne AM en un certain nombre de parties égales, <lb/>comme en 10 ou 12; </s> <s xml:id="echoid-s10465" xml:space="preserve">mais, je me contenterai de ne la diviſer ici <lb/>qu’en ſix, afin de rendre la figure moins confuſe: </s> <s xml:id="echoid-s10466" xml:space="preserve">il faut diviſer de <lb/>même l’Arc CE en autant de parties égales que la ligne AM, & </s> <s xml:id="echoid-s10467" xml:space="preserve">par <lb/>chaque point de diviſion mener des paralleles à l’Axe: </s> <s xml:id="echoid-s10468" xml:space="preserve">on menera <lb/>auſſi par les points I d’autres paralleles au diamêtre CD, qui, venant <lb/>rencontrer les précédentes, donneront les points K qui marqueront <lb/>de combien la Colomne doit diminuer. </s> <s xml:id="echoid-s10469" xml:space="preserve">Or, pour tracer cette dimi-<lb/>nution, il faut prendre une grande Regle flexible, & </s> <s xml:id="echoid-s10470" xml:space="preserve">la faire paſſer <lb/>par tous les points que la courbe doit rencontrer.</s> <s xml:id="echoid-s10471" xml:space="preserve"/> </p> <div xml:id="echoid-div465" type="float" level="2" n="1"> <note position="right" xlink:label="note-0505-01" xlink:href="note-0505-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>48.</note> </div> </div> <div xml:id="echoid-div467" type="section" level="1" n="124"> <head xml:id="echoid-head337" style="it" xml:space="preserve">Maniere de renfler les Colomnes.</head> <p> <s xml:id="echoid-s10472" xml:space="preserve">Ayant déterminé les meſures de la Colomne & </s> <s xml:id="echoid-s10473" xml:space="preserve">tiré le diamêtre <lb/>DE, qui doit paſſer par le tiers de l’Axe AB comme ci-devant, il <lb/>faut avec le Compas prendre le demi-diamêtre CE, (que je ſupoſe <lb/>égal à celui de la Colomne) & </s> <s xml:id="echoid-s10474" xml:space="preserve">le porter à l’extrémité G du diamê-<lb/>tre GH, enſorte que venant rencontrer l’Axe AB au point I, la <lb/>ligne GI ſoit égale au demi-diamêtre CE: </s> <s xml:id="echoid-s10475" xml:space="preserve">enſuite il faut prolonger <lb/>cette ligne auſſi-bien que le diamêtre DE, de maniere que l’un & </s> <s xml:id="echoid-s10476" xml:space="preserve"><lb/>l’autre, venant ſerencontrer, donnent le point F, duquel il faut tirer <lb/>un nombre de lignes qui viendront couper l’Axe de la Colomne, <pb o="46" file="0506" n="553" rhead="LA SCIENCE DES INGENIEURS,"/> en autant de points differens LL &</s> <s xml:id="echoid-s10477" xml:space="preserve">c. </s> <s xml:id="echoid-s10478" xml:space="preserve">au-deſſus & </s> <s xml:id="echoid-s10479" xml:space="preserve">au-deſſous du point <lb/>C; </s> <s xml:id="echoid-s10480" xml:space="preserve">ſur chacune de ces lignes au de-là de l’Axe, il faut faire LK égal <lb/>à GI, c’eſt-à-dire au demi-diamêtre CE, & </s> <s xml:id="echoid-s10481" xml:space="preserve">alors on aura tous les <lb/>points K, par leſquels doit paſſer la courbe qui fera le renfle-<lb/>ment & </s> <s xml:id="echoid-s10482" xml:space="preserve">la diminution de la Colomne.</s> <s xml:id="echoid-s10483" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10484" xml:space="preserve">Ce que l’on vient d’enſeigner, au ſujet de la diminution & </s> <s xml:id="echoid-s10485" xml:space="preserve">du ren-<lb/>flement des Colomnes, ſert pour tracer l’épure, c’eſt-à-dire le pa-<lb/>tron, à l’aide duquel on pourra creuſer dans une planche la cour-<lb/>bure dont il s’agit, afin qu’appliquant enſuite cette concavité ſur le <lb/>vif de la Colomne, on puiſſe, en la faiſant tourner à l’entour de <lb/>l’Axe, diminuer le Fuſt, & </s> <s xml:id="echoid-s10486" xml:space="preserve">lui donner une figure qui s’accorde par-<lb/>faitement avec ce que l’on aura tracé en premier lieu.</s> <s xml:id="echoid-s10487" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10488" xml:space="preserve">La difficulté d’avoir des pierres d’une aſſés belle grandeur, pour <lb/>faire des Colonnes toutes d’une piéce, n’embarraſſoit guére les An-<lb/>ciens; </s> <s xml:id="echoid-s10489" xml:space="preserve">lorſqu’ils étoient contraints de les faire de pluſieurs morceaux, <lb/>ils les poſoient avec tant de précaution les uns ſur les autres, que <lb/>les joints ne paroiſſoient point: </s> <s xml:id="echoid-s10490" xml:space="preserve">pour cela, ils laiſſoient le parement <lb/>brut, comme je l’ai dit ailleurs, mais ils étoient très attentifs à tail-<lb/>ler les pierres juſtes ſur leurs lits, afin qu’elles ſe rencontraſſent <lb/>parfaitement; </s> <s xml:id="echoid-s10491" xml:space="preserve">ſe gardant bien de ſe ſervir de Cales pour les dreſ-<lb/>ſer & </s> <s xml:id="echoid-s10492" xml:space="preserve">les ficher comme nous faiſons aujourd’hui; </s> <s xml:id="echoid-s10493" xml:space="preserve">& </s> <s xml:id="echoid-s10494" xml:space="preserve">lors qu’elles <lb/>étoient toutes poſées, ils les poliſſoient & </s> <s xml:id="echoid-s10495" xml:space="preserve">donnoient à leur face la <lb/>figure qu’elles devoient former, pouſſant les moulures les plus dé-<lb/>licates ſur le Tas, parce qu’autrement elles n’auroient pû ſe ren-<lb/>contrer juſtes, ſi elles avoient été taillées chacune à part.</s> <s xml:id="echoid-s10496" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10497" xml:space="preserve">Il y a aparence que les Anciens n’ont jamais employé d’autres <lb/>Colomnes que la Circulaire, puiſque toutes celles qui nous reſtent <lb/>ont cette figure; </s> <s xml:id="echoid-s10498" xml:space="preserve">& </s> <s xml:id="echoid-s10499" xml:space="preserve">je croi qu’il n’y a que le mauvais goût de quel-<lb/>ques Architectes modernes, qui en ait pû imaginer d’Ovales, de <lb/>Triangulaires, & </s> <s xml:id="echoid-s10500" xml:space="preserve">à Pans. </s> <s xml:id="echoid-s10501" xml:space="preserve">Un défaut inſuportable des Colomnes <lb/>Ovales, c’eſt que, ſi elles font face par le côté du plus grand diamê-<lb/>tre, & </s> <s xml:id="echoid-s10502" xml:space="preserve">qu’on veuille ſe ſervir de ce diamêtre comme de modules, <lb/>elles deviennent d’une hauteur extravagante lorſqu’on les regarde <lb/>du côté le plus étroit, parceque le petit diamêtre n’a plus de pro-<lb/>portion avec la hauteur de la Colomne le contraire arrive, ſi l’on <lb/>veut prendre le petit diamêtre: </s> <s xml:id="echoid-s10503" xml:space="preserve">pour module, car quand on vient <lb/>à les regarder du côté du grand, elles ſont trop baſſes & </s> <s xml:id="echoid-s10504" xml:space="preserve">trop écra-<lb/>ſées. </s> <s xml:id="echoid-s10505" xml:space="preserve">Je ne dis rien des Colomnes Triangulaires, étant ſi défectueu-<lb/>ſes, qu’elles ne meritent pas qu’on s’y arrête: </s> <s xml:id="echoid-s10506" xml:space="preserve">à l’égard de celles qui <lb/>ſont à Pans, je les trouve plus ſuportables; </s> <s xml:id="echoid-s10507" xml:space="preserve">mais, après tout, quelle ne-<lb/>ceſſité de vouloir donner aux Colomnes des figures extraordinaires?</s> <s xml:id="echoid-s10508" xml:space="preserve"> <pb o="47" file="0507" n="554" rhead="LIVRE V. DE LA DE’CORATION."/> Eſt-il poſſible, que les hommes ayent tant de peine à ſe conſormer <lb/>aux Regles de la Nature, & </s> <s xml:id="echoid-s10509" xml:space="preserve">qu’ils ne ſeront jamais convaincus que <lb/>ce n’eſt qu’en l’imitant qu’on peut réuſſir!</s> </p> <p> <s xml:id="echoid-s10510" xml:space="preserve">Les Colomnes Torſes paroiſſent auſſi peu aprouvées des habiles <lb/>gens; </s> <s xml:id="echoid-s10511" xml:space="preserve">car, les Colomnes étant faites pour ſoutenir un fardeau, <lb/>la raiſon veut qu’on leur donne toute la force qu’elles peuvent avoir: <lb/></s> <s xml:id="echoid-s10512" xml:space="preserve">ainſi, c’eſt un défaut de les affoiblir par des retours qui les éloi-<lb/>gnent de la perpendiculaire. </s> <s xml:id="echoid-s10513" xml:space="preserve">Cependant, leur beauté a fait qu’on n’a <lb/>point eu égard à cette conſideration, puiſqu’on les employe au-<lb/>jourd’hui comme un des plus beaux ornemens qu’il y ait dans l’Ar-<lb/>chitecture, non pas à la verité à des endroits qui demandent de la <lb/>ſolidité, mais dans des lieux de diſtinction, comme aux Autels, <lb/>aux Tombeaux, aux Salons, &</s> <s xml:id="echoid-s10514" xml:space="preserve">c. </s> <s xml:id="echoid-s10515" xml:space="preserve">Au reſte, comme les occaſions de <lb/>s’en ſervir ſemblent n’avoir pas grand raport avec un Traité comme <lb/>celui-ci, je ne m’arrêterai point à montrer comme on s’y prend <lb/>pour les tracer, parce que d’ailleurs il n’y a point de Livre d’Archi-<lb/>tecture où elle ne ſe trouve.</s> <s xml:id="echoid-s10516" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10517" xml:space="preserve">Il y a auſſi des Colomnes ſimboliques, & </s> <s xml:id="echoid-s10518" xml:space="preserve">qui repreſentent des Fi-<lb/>gures humaines: </s> <s xml:id="echoid-s10519" xml:space="preserve">leur origine vient des Grecs, qui, voulant conſer-<lb/>ver la memoire de leurs victoires, donnoient ſouvent, aux Colom-<lb/>nes de leurs édifices publics, la Figure & </s> <s xml:id="echoid-s10520" xml:space="preserve">la Reſſemblance de leurs <lb/>ennemis. </s> <s xml:id="echoid-s10521" xml:space="preserve">Les femmes des Cariens ayant été reduites en ſervitude, <lb/>& </s> <s xml:id="echoid-s10522" xml:space="preserve">les Perſes vaincus par les Lacedemoniens à la Bataille de Platée, <lb/>furent les premiers ſujets de ces Colomnes; </s> <s xml:id="echoid-s10523" xml:space="preserve">de-là ſont dérivez les <lb/>noms des Cariatides & </s> <s xml:id="echoid-s10524" xml:space="preserve">des Perſiques, qu’on a donnez depuis aux Co-<lb/>lomnes qui ont été faites ſous des Figures humaines: </s> <s xml:id="echoid-s10525" xml:space="preserve">cependant, on ne <lb/>donne plus aux Cariatides des repreſentations d’eſclavage & </s> <s xml:id="echoid-s10526" xml:space="preserve">de ſer-<lb/>vitude comme autrefois; </s> <s xml:id="echoid-s10527" xml:space="preserve">ces caracteres étant trop injurieux au beau <lb/>ſexe, on leur en donne de tout oppoſées, ne les employant plus que <lb/>ſous les ſimboles de Prudence, de Sageſſe, de Juſtice, de Temperan-<lb/>ce, &</s> <s xml:id="echoid-s10528" xml:space="preserve">c. </s> <s xml:id="echoid-s10529" xml:space="preserve">Quand elles ſont izolées, elles ne doivent porter tout au <lb/>plus que quelque Balcon, Tribune, ou Couronnement leger; </s> <s xml:id="echoid-s10530" xml:space="preserve">mais, <lb/>lorſqu’elles joignent un mur, il eſt à propos de les mettre ſous une <lb/>Conſole qui paroiſſe porter tout le poids de l’Entablement.</s> <s xml:id="echoid-s10531" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10532" xml:space="preserve">Les Colomnes Perſiques ſont le plus ſouvent repreſentées ſous <lb/>des Figures d’hommes nerveux & </s> <s xml:id="echoid-s10533" xml:space="preserve">barbus; </s> <s xml:id="echoid-s10534" xml:space="preserve">elles conviennent beau-<lb/>coup mieux que celles des femmes, pour repreſenter l’eſclavage: <lb/></s> <s xml:id="echoid-s10535" xml:space="preserve">on en fait auſſi des ſimboles de Vertu, de Force, de Valeur, & </s> <s xml:id="echoid-s10536" xml:space="preserve"><lb/>même des Divinitez de la Fable, comme quand on leur donne des <lb/>Figures d’Hercule, de Mars, de Mercure, ou de Faune & </s> <s xml:id="echoid-s10537" xml:space="preserve">de <lb/>Satire.</s> <s xml:id="echoid-s10538" xml:space="preserve"/> </p> <pb o="48" file="0508" n="555" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s10539" xml:space="preserve">Il y a encore d’autres Colomnes Simboliques de Figures humai-<lb/>nes, dont la moitié du corps paroit ſortir d’une gaine: </s> <s xml:id="echoid-s10540" xml:space="preserve">ces Co-<lb/>lomnes ſont nommées Thermes, & </s> <s xml:id="echoid-s10541" xml:space="preserve">ne doivent jamais entrer en pa-<lb/>rallele avec d’autres Colomnes, non plus que les Cariatides; </s> <s xml:id="echoid-s10542" xml:space="preserve">cepen-<lb/>dant, elles ont cet avantage qu’on leur donne telle élegance que l’on <lb/>veut, en allongeant leurs gaines pour les faire monter à une hau-<lb/>teur convenable à l’Entablement qui eſt au-deſſus.</s> <s xml:id="echoid-s10543" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10544" xml:space="preserve">Comme les Figures contribuent extrémement à enrichir la Déco-<lb/>ration, & </s> <s xml:id="echoid-s10545" xml:space="preserve">qu’il faut beaucoup d’Art pour qu’elles accompagnent les <lb/>Ordres agreablement, voici quelques Obſervations de Mr. </s> <s xml:id="echoid-s10546" xml:space="preserve">de la Hi-<lb/>re, tirées du Traité d’Architecture qu’il a dicté autrefois dans ſon <lb/>Ecole du Louvre.</s> <s xml:id="echoid-s10547" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10548" xml:space="preserve">Je ſupoſe ici que l’Ordre eſt Ionique & </s> <s xml:id="echoid-s10549" xml:space="preserve">qu’il tient le milieu en-<lb/>tre les autres, afin de faire une comparaiſon plus juſte, & </s> <s xml:id="echoid-s10550" xml:space="preserve">qui con-<lb/>vienne mieux entre les Figures & </s> <s xml:id="echoid-s10551" xml:space="preserve">les Colomnes; </s> <s xml:id="echoid-s10552" xml:space="preserve">je ſupoſe auſſi que <lb/>la Colomne a 18 modules ou 9 diamêtres de hauteur.</s> <s xml:id="echoid-s10553" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10554" xml:space="preserve">Je prens d’abord une Colomne d’une moyenne groſſeur, dont <lb/>la hauteur eſt de 18 pieds & </s> <s xml:id="echoid-s10555" xml:space="preserve">le diamêtre de 2 pieds, & </s> <s xml:id="echoid-s10556" xml:space="preserve">je trouve <lb/>par experience qu’une Figure qui a 6 pieds de hauteur peut fort <lb/>bien l’accompagner: </s> <s xml:id="echoid-s10557" xml:space="preserve">cette Figure ſera donc le tiers de la hauteur <lb/>de la Colomne.</s> <s xml:id="echoid-s10558" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10559" xml:space="preserve">Si la Colomne a 27 pieds de hauteur ou 3 pieds de diamêtre, l’on <lb/>peut donner à la Figure 7 pieds & </s> <s xml:id="echoid-s10560" xml:space="preserve">demi: </s> <s xml:id="echoid-s10561" xml:space="preserve">ſi elle a 36 pieds de hau-<lb/>teur & </s> <s xml:id="echoid-s10562" xml:space="preserve">4 pieds de diamêtre, la Figure peut avoir environ 9 pieds: <lb/></s> <s xml:id="echoid-s10563" xml:space="preserve">ſi elle a 45 pieds de hauteur & </s> <s xml:id="echoid-s10564" xml:space="preserve">5 de diamêtre, la Figure peut en <lb/>avoir 10 & </s> <s xml:id="echoid-s10565" xml:space="preserve">demi; </s> <s xml:id="echoid-s10566" xml:space="preserve">enfin, ſi la Colomne a 54 pieds de hauteur & </s> <s xml:id="echoid-s10567" xml:space="preserve">6 <lb/>pieds de diamêtre, on peut donner à la Figure 12 pieds de hau-<lb/>teur.</s> <s xml:id="echoid-s10568" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10569" xml:space="preserve">Dans ces proportions la Figure eſt augmentée depuis 6 pieds, à <lb/>raiſon d’un pied par toiſe d’augmentation à la hauteur de la Co-<lb/>lomne; </s> <s xml:id="echoid-s10570" xml:space="preserve">mais, ſi la Colomne n’a que 12 pieds de hauteur & </s> <s xml:id="echoid-s10571" xml:space="preserve">un pied <lb/>& </s> <s xml:id="echoid-s10572" xml:space="preserve">demi de diamêtre, une Figure de 5 pieds peut fort bien y conve-<lb/>nir. </s> <s xml:id="echoid-s10573" xml:space="preserve">Si elle n’avoit que 9 pieds de hauteur, on y pourra mettre une <lb/>Figure de 4 pieds & </s> <s xml:id="echoid-s10574" xml:space="preserve">demi: </s> <s xml:id="echoid-s10575" xml:space="preserve">ce qui montre auſſi que la même regle <lb/>pourra ſervir pour les Colomnes plus petites que 18 pieds, en di-<lb/>minuant la hauteur des Figures au-deſſous de la moyenne qui eſt de <lb/>6 pieds, à raiſon d’un pied par toiſe de diminution de hauteur à la <lb/>Colomne, & </s> <s xml:id="echoid-s10576" xml:space="preserve">ſemblablement dans une même raiſon pour les hau-<lb/>teurs qui ſont entre deux.</s> <s xml:id="echoid-s10577" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10578" xml:space="preserve">Pour ce qui eſt de la proportion que doivent avoir entr’elles des <lb/>Figures poſées en differente hauteur, il n’eſt pas poſſible d’en don- <pb o="49" file="0509" n="556" rhead="LIVRE V. DE LA DE’CORATION."/> ner de meſures certaines à cauſe qu’on juge la Figure plus ou moins <lb/>éloignée de l’œil ſuivant les accompagnemens. </s> <s xml:id="echoid-s10579" xml:space="preserve">On doit auſſi remar-<lb/>quer que les Figures, qu’on met ſur les Colomnes, doivent être un <lb/>peu plus grandes que celles qui ſont poſées contre les Bâtimens, <lb/>ou dans une Niche; </s> <s xml:id="echoid-s10580" xml:space="preserve">& </s> <s xml:id="echoid-s10581" xml:space="preserve">moins groſſes & </s> <s xml:id="echoid-s10582" xml:space="preserve">moins garnies de Draperie <lb/>que celles qui ſont izolées, & </s> <s xml:id="echoid-s10583" xml:space="preserve">qui n’ont point d’autres fond que le <lb/>Ciel.</s> <s xml:id="echoid-s10584" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div468" type="section" level="1" n="125"> <head xml:id="echoid-head338" xml:space="preserve">CHAPITRE NEUVIE’ME.</head> <head xml:id="echoid-head339" style="it" xml:space="preserve">De la Proportion des Pilaſtres & des Frontons.</head> <p> <s xml:id="echoid-s10585" xml:space="preserve">LES Pilaſtres ſont des Colomnes quarrées de pluſieurs eſpeces, <lb/>dont les differences ſe prennent de la maniere qu’elles ſont ap-<lb/>pliquées au mur: </s> <s xml:id="echoid-s10586" xml:space="preserve">il y en a d’entierement izolées, d’autres attachées <lb/>aux encoignures des Edifices & </s> <s xml:id="echoid-s10587" xml:space="preserve">qui n’ont que deux faces, d’autres <lb/>qui étant enfoncées en partie dans le mur ne preſentent que la face <lb/>de devant, & </s> <s xml:id="echoid-s10588" xml:space="preserve">ce ſont les plus en uſage aujourd’hui.</s> <s xml:id="echoid-s10589" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10590" xml:space="preserve">Les Pilaſtres quarrés & </s> <s xml:id="echoid-s10591" xml:space="preserve">izolés s’employent aux extrêmités des <lb/>Portiques, pour donner plus de fermeté aux encoignures: </s> <s xml:id="echoid-s10592" xml:space="preserve">les autres, <lb/>qui ſont engagés dans le mur, ſervent à décorer les Edifices avec <lb/>beaucoup de grace; </s> <s xml:id="echoid-s10593" xml:space="preserve">mais, pour qu’ils puiſſent réüſſir, il y a pluſieurs <lb/>choſes à obſerver à l’égard de leurs ſaillies, de leur diminution, de <lb/>la maniere que l’Entablement doit poſer deſſus, & </s> <s xml:id="echoid-s10594" xml:space="preserve">de la façon qu’ils <lb/>doivent être canelés.</s> <s xml:id="echoid-s10595" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10596" xml:space="preserve">La’ſaillie des Pilaſtres, qui n’ont qu’une face hors du mur, doit <lb/>être de toute la moitié, ou ne ſortir au plus que de la ſixiéme partie <lb/>lorſqu’il n’y a aucune raiſon qui oblige de lui en donner davantage: <lb/></s> <s xml:id="echoid-s10597" xml:space="preserve">par exemple, quand les Pilaſtres doivent recevoir des impoſtes qui <lb/>viennent profiler contre leurs côtés, il faut alors leur donner pour <lb/>ſaillie le quart du diamêtre, c’eſt-à-dire le quart de la face qui tient <lb/>lieu ici de diamêtre; </s> <s xml:id="echoid-s10598" xml:space="preserve">& </s> <s xml:id="echoid-s10599" xml:space="preserve">cette proportion a cela de commode, qu’el-<lb/>le n’oblige point à tronquer irrégulierement les Chapiteaux Corin-<lb/>thien & </s> <s xml:id="echoid-s10600" xml:space="preserve">Compoſite, car il ſe rencontre que la feüille d’en bas eſt <lb/>coupée juſtement par la moitié, & </s> <s xml:id="echoid-s10601" xml:space="preserve">qu’à l’Ordre Corinthien la Ti-<lb/>gette eſt coupée de même: </s> <s xml:id="echoid-s10602" xml:space="preserve">par cette raiſon, lorſqu’on employe des <lb/>demi Pilaſtres aux angles rentrans, il faut leur donner un peu plus <lb/>de la moitié de leur diamêtre.</s> <s xml:id="echoid-s10603" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10604" xml:space="preserve">On ne diminuë point ordinairement les Pilaſtres lorſqu’ils n’ont <pb o="50" file="0510" n="557" rhead="LA SCIENCE DES INGENIEURS,"/> qu’une face hors du mur; </s> <s xml:id="echoid-s10605" xml:space="preserve">mais quand il s’en trouve ſur un même <lb/>allignement avec des Colomnes, & </s> <s xml:id="echoid-s10606" xml:space="preserve">qu’on veut faire paſſer l’Enta-<lb/>blement ſur les uns & </s> <s xml:id="echoid-s10607" xml:space="preserve">ſur les autres, il faut alors donner aux Pi-<lb/>laſtres la même diminution qu’aux Colomnes: </s> <s xml:id="echoid-s10608" xml:space="preserve">cela s’entend de la <lb/>face de devant, car pour les côtés doivent reſter auſſi larges en haut <lb/>qu’en bas; </s> <s xml:id="echoid-s10609" xml:space="preserve">mais, quand le Pilaſtre a deux faces hors du mur, comme <lb/>cela arrive aux encoignures, & </s> <s xml:id="echoid-s10610" xml:space="preserve">qu’il y en a une qui regarde une Co-<lb/>lomne, cette face doit être diminuée de même que la Colomne.</s> <s xml:id="echoid-s10611" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10612" xml:space="preserve">Les canelures, qui ſe font quelquefois aux Pilaſtres, doivent toû-<lb/>jours être en nombre impair, afin qu’il s’en trouve une dans le mi-<lb/>lieu; </s> <s xml:id="echoid-s10613" xml:space="preserve">mais, s’il s’agit des demi Pilaſtres qui ſe rencontrent aux an-<lb/>gles rentrans, on ajoûte une canelure afin que le nombre en ſoit <lb/>pair, & </s> <s xml:id="echoid-s10614" xml:space="preserve">alors on en donne la moitié d’un côté & </s> <s xml:id="echoid-s10615" xml:space="preserve">la moitié de l’au-<lb/>tre; </s> <s xml:id="echoid-s10616" xml:space="preserve">c’eſt-à-dire que ſi dans un Pilaſtre entier on en mettoit 7, il <lb/>en faudroit 4 à chaque demi Pilaſtre.</s> <s xml:id="echoid-s10617" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10618" xml:space="preserve">Les proportions des Baſes des Chapiteaux & </s> <s xml:id="echoid-s10619" xml:space="preserve">de l’Entablement <lb/>pour les Pilaſtres ſont les mêmes que celles des Colomnes de <lb/>l’Ordre ſelon lequel on veut faire la Décoration: </s> <s xml:id="echoid-s10620" xml:space="preserve">ainſi, je ne ſache <lb/>point qu’il y ait aucunes regles particulieres à donner qui ſoient <lb/>differentes de celles que nous avons enſeignées pour la compoſi-<lb/>tion des ordonnances en general.</s> <s xml:id="echoid-s10621" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10622" xml:space="preserve">Quand les Pilaſtres ſont engagés dans le mur, il faut prendre garde <lb/>qu’ils ſaillent aſſés en dehors pour recevoir les Corniches des Por-<lb/>tes, des Fenêtres, & </s> <s xml:id="echoid-s10623" xml:space="preserve">des autres ouvertures qui ſeront entre-deux, les <lb/>ſaillies des Corniches faiſant un bon effet, lorſqu’étant continuées <lb/>elles viennent mourir juſtement dans les flancs des Pilaſtres. </s> <s xml:id="echoid-s10624" xml:space="preserve">C’eſt <lb/>pourquoi Scamozzy veut que les Pilaſtres ne ſortent au plus hors <lb/>du mur que d’un quart de leur largeur: </s> <s xml:id="echoid-s10625" xml:space="preserve">car, par ce moyen, dit-il, <lb/>ils pourront recevoir dans leurs côtés toutes les ſaillies des orne-<lb/>mens des Portes & </s> <s xml:id="echoid-s10626" xml:space="preserve">Fenêtres, qui ne doivent jamais exceder les Pi-<lb/>laſtres; </s> <s xml:id="echoid-s10627" xml:space="preserve">quoiqu’il y ait des exemples antiques & </s> <s xml:id="echoid-s10628" xml:space="preserve">modernes, où l’on <lb/>remarque que ces ſaillies s’avançent, non-ſeulement au-delà des Pi-<lb/>laſtres, mais même des Colomnes qu’elles embraſſent en paſſant, <lb/>ce qui fait un très-mauvais effet. </s> <s xml:id="echoid-s10629" xml:space="preserve">Mais, s’il arrivoit qu’on fût obligé <lb/>de donner aux Corniches des Portes ou des Fenêtres des ſaillies plus <lb/>grandes que ne ſont les flancs des Pilaſtres, il vaudroit en ce cas <lb/>beaucoup mieux couper ces Corniches au droit des Tableaux des <lb/>Portes ou Fenêtres, & </s> <s xml:id="echoid-s10630" xml:space="preserve">les continuer en Platte-Bande ſeulement <lb/>couronnées de quelques Cymaiſes ou autres moulures, qui toutes <lb/>enſemble euſſent autant de ſaillie que le flanc du Pilaſtre, que de les <lb/>faire avancer avec toute leur portée.</s> <s xml:id="echoid-s10631" xml:space="preserve"/> </p> <pb o="51" file="0511" n="558" rhead="LIVRE V. DE LA DE’CORATION."/> <p> <s xml:id="echoid-s10632" xml:space="preserve">Lorſque les Pilaſtres engagés dans le mur n’ont pas trop de ſail-<lb/>lie, l’on peut faire regner les Architraves ſans interruption, & </s> <s xml:id="echoid-s10633" xml:space="preserve">les <lb/>laiſſer déborder en dehors du mur qui eſt entre les Pilaſtres, d’au-<lb/>tant qu’ils ont de ſaillie: </s> <s xml:id="echoid-s10634" xml:space="preserve">mais, quand ils en ont par trop, il faut re-<lb/>tirer les Architraves en dedans; </s> <s xml:id="echoid-s10635" xml:space="preserve">& </s> <s xml:id="echoid-s10636" xml:space="preserve">en ce cas, ou J’on rompt les En-<lb/>tablemens en les faiſant reſſaillir ſur les Pilaſtres, ou bien l’on ſe-<lb/>contente de donner ces reſſauts à l’Architrave ſeul, ou quelque-<lb/>fois même à l’Architrave & </s> <s xml:id="echoid-s10637" xml:space="preserve">la Friſe, laiſſant paſſer le reſte de l’En-<lb/>tablement depuis un Pilaſtre juſqu’à l’autre ſans interruption.</s> <s xml:id="echoid-s10638" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10639" xml:space="preserve">L’on peut faire le même raiſonnement ſur les Pilaſtres qui ſe met-<lb/>tent aux encoignures des murs: </s> <s xml:id="echoid-s10640" xml:space="preserve">car, s’ils font face des deux côtés, <lb/>il faut que les Architraves & </s> <s xml:id="echoid-s10641" xml:space="preserve">les autres parties des Entablemens <lb/>courent dans les retours ſur les murs des flancs, de la même ma-<lb/>niere qu’ils auront été mis ſur celui de la façade; </s> <s xml:id="echoid-s10642" xml:space="preserve">c’eſt-à-dire, ſans <lb/>reſſauts ou avec reſſauts, ſi ce n’eſt qu’ayant donné aux Pilaſtres <lb/>beaucoup de ſaillie ſur les faces de devant, qui ayent obligé à faire <lb/>des reſſauts dans l’Entablement, on ne la retranche ſur les flancs, <lb/>& </s> <s xml:id="echoid-s10643" xml:space="preserve">par ce moyen on peut faire courir l’Architrave & </s> <s xml:id="echoid-s10644" xml:space="preserve">le reſte de l’En-<lb/>tablement ſans interruption.</s> <s xml:id="echoid-s10645" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10646" xml:space="preserve">Si le Pilaſtre angulaire ſe termine ſur, l’allignement du mur de cô-<lb/>té, ſansy faire face, & </s> <s xml:id="echoid-s10647" xml:space="preserve">ſans avoir aucune ſaillie au dehors de cette part, <lb/>il faut en ce cas que l’Entablement qui eſt ſur le devant vienne mou-<lb/>rir dans le retour du coin du flanc du Pilaſtre, ſans le faire paſſer <lb/>ſur le mur de côté; </s> <s xml:id="echoid-s10648" xml:space="preserve">ou ſi l’on veut que le flanc ſoit couvert de l’En-<lb/>tablement, il faut que le coin du retour de l’Architrave ſoit au <lb/>dehors du vif du Pilaſtre.</s> <s xml:id="echoid-s10649" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10650" xml:space="preserve">Quelquefois, quand le dernier Pilaſtre de la façade ne ſe trouve <lb/>point ſur le coin du retour, & </s> <s xml:id="echoid-s10651" xml:space="preserve">laiſſe une Alete dans l’encoignure, <lb/>& </s> <s xml:id="echoid-s10652" xml:space="preserve">qu’il y ait un autre Pilaſtre à pareille diſtance dans le mur du flanc, <lb/>il faut faire tourner l’Entablement de l’un à l’autre avec des reſſauts <lb/>ſur le coin. </s> <s xml:id="echoid-s10653" xml:space="preserve">S’il s’en rencontre dans la façade, ou bien s’il n’y en a <lb/>point, on le fera paſſer droit ſur les côtés ſans reſſauts; </s> <s xml:id="echoid-s10654" xml:space="preserve">& </s> <s xml:id="echoid-s10655" xml:space="preserve">s’il n’y <lb/>avoit point de Pilaſtres ſur le côté, il faudroit continuer l’Entable-<lb/>ment de devant avec des reſſauts ou ſans reſſauts ſuivant l’ordonnance <lb/>de la façade juſques ſur le coin du mur, d’où il doit retourner tout <lb/>droit ſur les flancs, en laiſſant ſeulement à l’Architrave autant de <lb/>ſaillie qu’il lui en faut pour le dégager du mur.</s> <s xml:id="echoid-s10656" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10657" xml:space="preserve">Toutes ces pratiques ſont bonnes, & </s> <s xml:id="echoid-s10658" xml:space="preserve">il y en a de beaux exemples <lb/>dans les Ouvrages les plus aprouvés; </s> <s xml:id="echoid-s10659" xml:space="preserve">mais, dans tout ceci, il faut re-<lb/>marquer que l’on ſupoſe que les Pilaſtres ſont ſeuls, & </s> <s xml:id="echoid-s10660" xml:space="preserve">n’accompa-<lb/>gnent point de Colomnes.</s> <s xml:id="echoid-s10661" xml:space="preserve"/> </p> <pb o="52" file="0512" n="559" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s10662" xml:space="preserve">Les Frontons augmentent auſſi beaucoup la beauté des façades <lb/>lorſqu’ils ſont mis à propos; </s> <s xml:id="echoid-s10663" xml:space="preserve">mais, pour qu’ils ayent plus de grace, <lb/>il faut que le corps qui en eſt couronné faſſe quelque ſaillie, afin <lb/>de ſe diſtinguer & </s> <s xml:id="echoid-s10664" xml:space="preserve">maîtriſer les autres parties continuées de l’Edifice.</s> <s xml:id="echoid-s10665" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10666" xml:space="preserve">Selon Scamozzy, pour avoir la plus belle proportion des Fron-<lb/> <anchor type="note" xlink:label="note-0512-01a" xlink:href="note-0512-01"/> tons, il faut diviſer la Corniche AB qui lui ſert de Baſe en neuf <lb/>parties égales, & </s> <s xml:id="echoid-s10667" xml:space="preserve">en donner deux à la perpendiculaire EC, pour <lb/>déterminer la hauteur qu’il doit avoir depuis l’Entablement juſqu’au <lb/>ſommet; </s> <s xml:id="echoid-s10668" xml:space="preserve">cette proportion étant plus agréable à la vûë, que de lui <lb/>donner pour hauteur la cinquiéme partie de la Baſe comme font <lb/>quelques Architectes, & </s> <s xml:id="echoid-s10669" xml:space="preserve">plus commode pour faciliter l’écoulement <lb/>des eaux. </s> <s xml:id="echoid-s10670" xml:space="preserve">On peut auſſi tracer un cercle dont la Baſe AB ſervira de <lb/>diamêtre que l’on diviſera en deux également, par la perpendicu-<lb/>laire DF & </s> <s xml:id="echoid-s10671" xml:space="preserve">du point D comme centre, & </s> <s xml:id="echoid-s10672" xml:space="preserve">de l’intervale DA, on <lb/>décrira l’arc ACB qui venant couper la perpendiculaire au point C, <lb/>on n’aura qu’à tracer l’angle ACB, qui donnera celui qui doit for-<lb/>mer le Fronton. </s> <s xml:id="echoid-s10673" xml:space="preserve">L’on remarquera que cet angle eſt égal à celui <lb/>de la circonference d’un Octogonne, puiſque le point D, étant <lb/>le centre de l’arc que l’on a décrit, les deux rayons DA & </s> <s xml:id="echoid-s10674" xml:space="preserve">DB, <lb/>forment un angle droit.</s> <s xml:id="echoid-s10675" xml:space="preserve"/> </p> <div xml:id="echoid-div468" type="float" level="2" n="1"> <note position="left" xlink:label="note-0512-01" xlink:href="note-0512-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>48.</note> </div> <p> <s xml:id="echoid-s10676" xml:space="preserve">Il ſe fait auſſi des Frontons en portion de cercle qui ont la même <lb/>hauteur que les Triangulaires, puiſque l’Arc AGHB, qui en dé-<lb/>termine la figure, doit avoir pour centre le point D, dont nous <lb/>nous ſommes ſervi pour le précédent: </s> <s xml:id="echoid-s10677" xml:space="preserve">on peut donc dire, que les <lb/>Frontons ronds ſont compoſés d’un ſecment de cercle qui com-<lb/>prend le quart de la circonference.</s> <s xml:id="echoid-s10678" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10679" xml:space="preserve">Quand on a un rang de Fenêtres ſur un même alignement, & </s> <s xml:id="echoid-s10680" xml:space="preserve"><lb/>qu’on veut les couronner par des Frontons, il faut pour les varier les <lb/>faire alternativement ronds & </s> <s xml:id="echoid-s10681" xml:space="preserve">triangulaires; </s> <s xml:id="echoid-s10682" xml:space="preserve">enſorte qu’ils répon-<lb/>dent avec ſimétrie à droit & </s> <s xml:id="echoid-s10683" xml:space="preserve">à gauche du milieu de la façade, ainſi <lb/>qu’on l’a pratiqué à la Gallerie du Louvre & </s> <s xml:id="echoid-s10684" xml:space="preserve">aux Thuileries. </s> <s xml:id="echoid-s10685" xml:space="preserve">Ce-<lb/>pendant, quoique ce Bâtiment ſoit des plus magnifiques, & </s> <s xml:id="echoid-s10686" xml:space="preserve">qu’on <lb/>pourroit le citer pour exemple en bien des choſes, je ne ſaurois <lb/>m’empêcher de dire qu’il eſt ridicule de voir qu’on ait affecté d’y <lb/>mettre une ſi grande quantité de Frontons: </s> <s xml:id="echoid-s10687" xml:space="preserve">les choſes qui réüſſiſſent <lb/>le mieux ont beſoin d’être menagées; </s> <s xml:id="echoid-s10688" xml:space="preserve">autrement, quand elles ſont <lb/>trop repetées, elles apportent plus de confuſion que d’agrément.</s> <s xml:id="echoid-s10689" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10690" xml:space="preserve">Soit qu’on faſſe les Frontons triangulaires ou circulaires, la Cor-<lb/>niche qui couronne le timpan doit toûjours être ſemblable à celle <lb/>de l’Entablement: </s> <s xml:id="echoid-s10691" xml:space="preserve">il faut ſeulement remarquer, que la partie de la <lb/>Corniche qui ſert de Baſe au Fronton doit être ſans Cymaiſe, par- <pb o="53" file="0513" n="560" rhead="LIVRE V. DE LA DE’CORATION."/> ce que la Cymaiſe du reſte de la Corniche, venant à rencontrer le <lb/>Fronton, paſſe par-deſſus, comme on le peut voir dans les Figu-<lb/>res X & </s> <s xml:id="echoid-s10692" xml:space="preserve">r de la Planche 48. </s> <s xml:id="echoid-s10693" xml:space="preserve">dont il y en a une qui marque plus <lb/>en grand que l’autre de quelle maniere la Corniche du Fronton <lb/>doit ſe rencontrer avec celle de l’Entablement.</s> <s xml:id="echoid-s10694" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10695" xml:space="preserve">Quand il y a des modillons à la Corniche de l’Entablement, on <lb/>en met auſſi à celle du Fronton; </s> <s xml:id="echoid-s10696" xml:space="preserve">& </s> <s xml:id="echoid-s10697" xml:space="preserve">ces derniers doivent ſe rencon-<lb/>trer à plomb avec ceux de l’Entablement. </s> <s xml:id="echoid-s10698" xml:space="preserve">Vitruve dit que les An-<lb/>ciens n’aprouvoient pas les Modillons dans la Corniche d’un Fron-<lb/>ton, parce que ſelon eux ces Modillons n’ayant été imaginés que <lb/>pour repreſenter des extrêmités de chevrons, c’étoit mal-à-propos <lb/>qu’on en vouloit exprimer dans les pentes d’un Fronton où il ne s’en <lb/>pouvoit rencontrer: </s> <s xml:id="echoid-s10699" xml:space="preserve">mais les Modillons étant plûtôt des ornemens <lb/>pour ſoulager la grande ſaillie du Larmier, que pour repreſenter des <lb/>chevrons ou autres pieces de Charpente, on ne doit point avoir égard <lb/>à ces prétenduës raiſons; </s> <s xml:id="echoid-s10700" xml:space="preserve">d’autant plus que ces ornemens font un <lb/>très-bon effet, ſur-tout quand on les employe dans de grands Fron-<lb/>tons.</s> <s xml:id="echoid-s10701" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10702" xml:space="preserve">Il eſt à remarquer, que le nud du Fronton, c’eſt-à-dire ſon Timpan <lb/>doit toûjours répondre à plomb ſur la Friſe de l’Entablement qui <lb/>eſt au-deſſous; </s> <s xml:id="echoid-s10703" xml:space="preserve">cependant, il eſt aſſés ordinaire d’y faire des orne-<lb/>mens de ſculpture qui repreſentent le caractere de l’Edifice: </s> <s xml:id="echoid-s10704" xml:space="preserve">on y met <lb/>quelquefois les Armes du Roy ou des Trophées, quand il s’agit de <lb/>quelque Bâtiment Militaire, comme on l’a pû voir ſur pluſieurs <lb/>Planches du quatriéme Livre.</s> <s xml:id="echoid-s10705" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10706" xml:space="preserve">Un Fronton pointu peut couronner juſquà trois Arcades ou trois <lb/>grandes Croiſées qui ſeroient dans le milieu de la façade d’un Bâ-<lb/>timent; </s> <s xml:id="echoid-s10707" xml:space="preserve">mais le rond ne peut couronner qu’une Arcade agréable-<lb/>ment: </s> <s xml:id="echoid-s10708" xml:space="preserve">& </s> <s xml:id="echoid-s10709" xml:space="preserve">quand on en voudra mettre deux l’un ſur l’autre, il eſt <lb/>bon que l’un ſoit ceintré & </s> <s xml:id="echoid-s10710" xml:space="preserve">l’autre pointu, & </s> <s xml:id="echoid-s10711" xml:space="preserve">que ce dernier termine <lb/>la façade en forme de Pignon. </s> <s xml:id="echoid-s10712" xml:space="preserve">Il y a des Architectes, qui ont mis <lb/>fort mal-à-propos deux Frontons l’un dans l’autre, comme on en <lb/>voit au vieux Louvre; </s> <s xml:id="echoid-s10713" xml:space="preserve">mais, en verité, de pareilles licences méritent <lb/>d’être ſifflées, & </s> <s xml:id="echoid-s10714" xml:space="preserve">choqueront toûjours les perſonnes de bon goût.</s> <s xml:id="echoid-s10715" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10716" xml:space="preserve">Vitruve voudroit que toutes les parties qui ſont au-deſſus des Co-<lb/>lomnes & </s> <s xml:id="echoid-s10717" xml:space="preserve">des Pilaſtres, c’eſt-à-dire qui ſont élevés au-deſſus de la <lb/>vûe, comme les faces de l’Architrave, la Friſe, le Timpan du Fron-<lb/>ton, les Acroteres, auſſi-bien que leurs Figures ou Statuës, fuſſent in-<lb/>clinés en devant de la 12<emph style="sub">e</emph> partie de leur hauteur; </s> <s xml:id="echoid-s10718" xml:space="preserve">mais, n’ayant pas <lb/>d’autre raiſon pour cela, que d’expoſer ces parties plus à la vûe de <lb/>ceux qui les regardent de bas en haut, je ne croi pas qu’on doive <pb o="54" file="0514" n="561" rhead="LA SCIENCE DES INGENIEURS,"/> ſuivre ſon ſentiment, qui n’eſt appuyé que d’une opinion particuliere <lb/>qui préjudicieroit conſiderablement à la régle generale, qui veut <lb/>que toutes les parties d’un Bâtiment & </s> <s xml:id="echoid-s10719" xml:space="preserve">d’une belle Architecture <lb/>ſoient bien à plomb, parce qu’autrement elles feroient un très-mé-<lb/>chant effet étant regardées de côté d’où elles paroîtroient comme <lb/>prêtes à tomber en devant. </s> <s xml:id="echoid-s10720" xml:space="preserve">Cependant, les Sculpteurs obſervent <lb/>cette maxime de Vitruve fort judicieuſement à l’égard de leurs Sta-<lb/>tues, lorſqu’elles doivent être élevées aſſés haut, & </s> <s xml:id="echoid-s10721" xml:space="preserve">qu’elles ne peu-<lb/>vent être vûes que par-devant & </s> <s xml:id="echoid-s10722" xml:space="preserve">de bas en haut.</s> <s xml:id="echoid-s10723" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10724" xml:space="preserve">Je ne dis rien des Frontons coupés pour faire place à des Ta-<lb/>bleaux ou à des Cartouches, de ceux qui ſont briſés ſur le haut & </s> <s xml:id="echoid-s10725" xml:space="preserve"><lb/>repliés en dedans, des autres roulés en Volute, ni de ceux qui ſont <lb/>renverſés la pointe en bas, n’y ayant rien de plus diſgracieux & </s> <s xml:id="echoid-s10726" xml:space="preserve">de <lb/>plus contraire à leur uſage, qui eſt de couvrir entierement ce qui <lb/>ſe trouve au-deſſous.</s> <s xml:id="echoid-s10727" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10728" xml:space="preserve">Il me reſte à parler des Acroteres, qui ſont des petits Piédeſtaux <lb/>que l’on met ſur le coin & </s> <s xml:id="echoid-s10729" xml:space="preserve">au ſommet des Frontons, afin d’y poſer <lb/>des Figures, comme on le peut voir ſur la 51<emph style="sub">e</emph> Planche. </s> <s xml:id="echoid-s10730" xml:space="preserve">Scamozzy, <lb/> <anchor type="note" xlink:label="note-0514-01a" xlink:href="note-0514-01"/> après avoir examiné la regle de Vitruve ſur ce ſujet, & </s> <s xml:id="echoid-s10731" xml:space="preserve">y avoir trou-<lb/>vé pluſieurs deffauts, en preſcrit une que Mr. </s> <s xml:id="echoid-s10732" xml:space="preserve">Blondel approuve <lb/>fort, qui eſt de faire la hauteur du Dé des Acroteres des coins, <lb/>égale à la ſaillie de la Corniche de l’Entablement, obſervant que ce-<lb/>lui du milieu, c’eſt-à-dire qui eſt poſé au ſommet du Fronton, ſoit <lb/>un peu plus élevé que les précedens.</s> <s xml:id="echoid-s10733" xml:space="preserve"/> </p> <div xml:id="echoid-div469" type="float" level="2" n="2"> <note position="left" xlink:label="note-0514-01" xlink:href="note-0514-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>51.</note> </div> <p> <s xml:id="echoid-s10734" xml:space="preserve">La largeur du Dé des Acroteres, ſuivant le même Architecte, <lb/>doit être égale à celle du haut des Colomnes auſquelles ils doivent <lb/>répondre: </s> <s xml:id="echoid-s10735" xml:space="preserve">mais, ceci ne peut avoir lieu que quand l’on ne met <lb/>qu’une Statue à chaque coin; </s> <s xml:id="echoid-s10736" xml:space="preserve">car, ſi l’on avoit deſſein d’y placer un <lb/>Groupe de Figures, il faudroit alors continuer la largeur des Acro-<lb/>teres, & </s> <s xml:id="echoid-s10737" xml:space="preserve">la faire mourir ſur les côtés du Fronton.</s> <s xml:id="echoid-s10738" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10739" xml:space="preserve">On ne fait point ordinairement de Baſe à ces ſortes de Piédeſtaux, <lb/>parce qu’elle ne ſeroit point vûe, à cauſe de la ſaillie de la Corniche <lb/>de l’Entablement; </s> <s xml:id="echoid-s10740" xml:space="preserve">ainſi, après avoir fait la hauteur du Dé égale à la <lb/>ſaillie de la Corniche de l’Entablement, comme nous le venons de <lb/>dire, il faut le couronner par une petite Corniche qui ſoit propor-<lb/>tionnée à la hauteur du même Dé, obſervant de ne lui donner que <lb/>peu de moulures, afin qu’on puiſſe les diſtinguer de loin.</s> <s xml:id="echoid-s10741" xml:space="preserve"/> </p> <pb file="0515" n="562"/> <pb file="0515a" n="563"/> <figure> <image file="0515a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0515a-01"/> </figure> <pb file="0516" n="564"/> <pb o="55" file="0517" n="565" rhead="LIVRE V. DE LA DE’CORATION."/> </div> <div xml:id="echoid-div471" type="section" level="1" n="126"> <head xml:id="echoid-head340" xml:space="preserve">CHAPITRE DIXIE’ME. <lb/>Des Periſtiles ou Colonnates, des Arcades, & des Niches.</head> <p> <s xml:id="echoid-s10742" xml:space="preserve">L’ON n’a rien imaginé juſqu’ici de plus grand & </s> <s xml:id="echoid-s10743" xml:space="preserve">de plus ſuper-<lb/>be pour orner les Bâtimens conſiderables, que les Periſtiles <lb/>ou Portiques. </s> <s xml:id="echoid-s10744" xml:space="preserve">Les Anciens s’en ſervoient aux Temples, aux Baſili-<lb/>ques, aux Places, & </s> <s xml:id="echoid-s10745" xml:space="preserve">aux Marchez publics: </s> <s xml:id="echoid-s10746" xml:space="preserve">nous avons en France <lb/>des morceaux dans ce genre qui feront à jamais l’admiration des <lb/>connoiſſeurs, entr’autres le Periſtile du Louvre à Paris, qui eſt <lb/>aſſurement l’ouvrage le plus achevé & </s> <s xml:id="echoid-s10747" xml:space="preserve">le plus parfait qu’ily ait. </s> <s xml:id="echoid-s10748" xml:space="preserve">C’eſt <lb/>encore ici, comme en tant d’autres choſes, que les Architectes an-<lb/>ciens & </s> <s xml:id="echoid-s10749" xml:space="preserve">modernes ſont fort partagés, pour déterminer les Entre-<lb/>Colomnes dans tous les Ordres; </s> <s xml:id="echoid-s10750" xml:space="preserve">car, il eſt aſſés difficile de ſavoir à <lb/>qui donner la préférence: </s> <s xml:id="echoid-s10751" xml:space="preserve">ce ſujet eſt pourtant eſſentiel pour la <lb/>beauté & </s> <s xml:id="echoid-s10752" xml:space="preserve">la ſolidité des Edifices, puiſqu’à le bien prendre c’en eſt-<lb/>là le point critique.</s> <s xml:id="echoid-s10753" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10754" xml:space="preserve">Quand les Colomnes ſont izolées & </s> <s xml:id="echoid-s10755" xml:space="preserve">qu’elles compoſent des Co-<lb/>lonnates, Vignole, pour en regler l’intervale dans l’Ordre Toſcan, <lb/>donne 4 modules deuxtiers du Fuſt de l’une au Fuſt de l’autre, dans <lb/>l’Ordre Dorique 5 & </s> <s xml:id="echoid-s10756" xml:space="preserve">demi, dans l’Ionique 4 & </s> <s xml:id="echoid-s10757" xml:space="preserve">demi, & </s> <s xml:id="echoid-s10758" xml:space="preserve">dans le Co-<lb/>rinthien & </s> <s xml:id="echoid-s10759" xml:space="preserve">le Compoſite 4 modules deux tiers comme au Toſcan; <lb/></s> <s xml:id="echoid-s10760" xml:space="preserve">ce qui eſt aſſés extraordinaire, d’avoir laiſſé des intervales égaux aux <lb/>Ordres les plus éloignés l’un de l’autre, comme ſont le Toſcan & </s> <s xml:id="echoid-s10761" xml:space="preserve"><lb/>le Corinthien, auſſi-bien que d’avoir fait les Entre-Colomnes Do-<lb/>riques plus grands que les Toſcans, contre le Sentiment de Vitru-<lb/>ve, qui veut que les Entre-Colomnes des Ordres maſſifs ſoient <lb/>plus grands que ceux des plus legers.</s> <s xml:id="echoid-s10762" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10763" xml:space="preserve">La Regle de Scamozzy eſt differente; </s> <s xml:id="echoid-s10764" xml:space="preserve">il donne 6 modules aux <lb/>Entre-Colomnes Toſcanes, 5 & </s> <s xml:id="echoid-s10765" xml:space="preserve">demi aux Doriques, 5 aux Ioni-<lb/>ques, 4 & </s> <s xml:id="echoid-s10766" xml:space="preserve">demiaux Compoſites, & </s> <s xml:id="echoid-s10767" xml:space="preserve">4 aux Corinthiens: </s> <s xml:id="echoid-s10768" xml:space="preserve">ainſi, il prend <lb/>trois nombres proportionnels Arithmetiques entre 6 & </s> <s xml:id="echoid-s10769" xml:space="preserve">4, qu’il <lb/>regarde comme les termes extrêmes de ces Entre-Colomnes. </s> <s xml:id="echoid-s10770" xml:space="preserve">Et <lb/>pour ne point tomber dans la faute qu’il reproche aux autres Ar-<lb/>chitectes, qui font tous leurs Entre-Colomnes égaux, il donne plus <lb/>de largeur à celui du milieu des façades, qu’aux autres qui ſont à <lb/>droit & </s> <s xml:id="echoid-s10771" xml:space="preserve">à gauche: </s> <s xml:id="echoid-s10772" xml:space="preserve">par exemple, ſelon lui, il faut que l’Entre-Colom-<lb/>ne du milieu pour l’Ordre Dorique ſoit plus grand que les autres <pb o="56" file="0518" n="566" rhead="LA SCIENCE DES INGENIEURS,"/> d’un Trigliphe & </s> <s xml:id="echoid-s10773" xml:space="preserve">d’un Metope; </s> <s xml:id="echoid-s10774" xml:space="preserve">& </s> <s xml:id="echoid-s10775" xml:space="preserve">à l’Ionique, au Compoſite, & </s> <s xml:id="echoid-s10776" xml:space="preserve"><lb/>au Corinthien, plus grands d’un Mutule.</s> <s xml:id="echoid-s10777" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10778" xml:space="preserve">Les Regles précédentes ne ſont point ſi genérales, qu’on ne puiſ-<lb/>ſe quelquefois s’en écarter, parce que l’Entablement des Ordres obli-<lb/>ge à certaines ſujetions, auſquelles il faut avoir égard abſolument <lb/>pour regler les Entre-Colomnes: </s> <s xml:id="echoid-s10779" xml:space="preserve">il n’y a que l’Ordre Toſcan qui <lb/>peut s’executer ſans aucune difficulté, parce qu’on n’eſt pas gêné <lb/>par les Trigliphes, les Denticules, ni les Modillons; </s> <s xml:id="echoid-s10780" xml:space="preserve">car il ſuffit <lb/>pour cet Ordre, que l’Entablement ſoit ſolidement établi, & </s> <s xml:id="echoid-s10781" xml:space="preserve">n’aye <lb/>pas trop de portée.</s> <s xml:id="echoid-s10782" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10783" xml:space="preserve">Il n’en eſt pas de même pour le Dorique, étant le plus difficile <lb/>de tous à mettre en œuvre, parce que la diſtance de ces Colom-<lb/>nes eſt déterminée par les eſpaces des Trigliphes & </s> <s xml:id="echoid-s10784" xml:space="preserve">des Metopes; <lb/></s> <s xml:id="echoid-s10785" xml:space="preserve">car entre deux Colomnes il ne peut y avoir que depuis un Trigli-<lb/>phe juſqu’à 5, prenant garde qu’on ne compte que ceux qui por-<lb/>tent ſur le vuide, & </s> <s xml:id="echoid-s10786" xml:space="preserve">non pas ceux qui ſont à plomb ſur les Colom-<lb/>nes. </s> <s xml:id="echoid-s10787" xml:space="preserve">Pluſieurs n’ont pas voulu ſe contraindre à la préciſion que cet <lb/>Ordre demande, & </s> <s xml:id="echoid-s10788" xml:space="preserve">ne ſe ſont point embarraſſés de s’aſſujetir à faire les <lb/>Metopes quarrés; </s> <s xml:id="echoid-s10789" xml:space="preserve">mais, comme c’eſt juſtement de-là que dépend la <lb/>beauté de cet Ordre, ceux qui n’ont pas ſuivi la maxime des Anciens <lb/>n’ont pas été aprouvés: </s> <s xml:id="echoid-s10790" xml:space="preserve">d’autres, pour n’être contraints en rien, ont <lb/>executé l’Ordre Dorique ſans Trigliphes ni Metopes, n’ayant mis <lb/>nulle diſtribution dans la Friſe, mais alors c’eſt le priver de ce qu’il <lb/>a de plus beau pour en faire un autre auquel on ne ſait quel nom <lb/>donner.</s> <s xml:id="echoid-s10791" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10792" xml:space="preserve">A l’égard des trois autres Ordres, la ſujetion n’en eſt pas ſi gran-<lb/>de pour regler les Entre-Colomnes, ne s’agiſſant que d’avoir égard <lb/>à la diſtribution des Modillons & </s> <s xml:id="echoid-s10793" xml:space="preserve">des Denticules, mais principale-<lb/>ment des Modillons, parce qu’on doit obſerver pour regle conſtan-<lb/>te, qu’il doit toûjours y en avoir un qui réponde au milieu de cha-<lb/>que Colomne; </s> <s xml:id="echoid-s10794" xml:space="preserve">& </s> <s xml:id="echoid-s10795" xml:space="preserve">c’eſt au jugement de l’Architecte, de propor-<lb/>tionner ſi bien la grandeur, la ſaillie, & </s> <s xml:id="echoid-s10796" xml:space="preserve">l’eſpace des autres, que le <lb/>tout puiſſe cadrer de maniere, qu’il ne paroiſſe pas qu’on ait été <lb/>gêné en rien.</s> <s xml:id="echoid-s10797" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10798" xml:space="preserve">Outre les cinq eſpeces d’Entre-Colomnes dont nous venons de <lb/>parler, les Modernes en ont inventé une ſixiéme, que l’on nomme <lb/>Colomnes Couplées; </s> <s xml:id="echoid-s10799" xml:space="preserve">parce qu’elles ſont deux à deux fort prés l’une <lb/>de l’autre; </s> <s xml:id="echoid-s10800" xml:space="preserve">par exemple, s’il y a pluſieurs Colomnes de ſuite diſ-<lb/>poſées ſelon les regles précédentes, on accouple la 2<emph style="sub">e</emph> avec la pre-<lb/>miere, la 4<emph style="sub">e</emph> avec la 3<emph style="sub">e</emph>, la 6<emph style="sub">e</emph> avec la 5<emph style="sub">e</emph>: </s> <s xml:id="echoid-s10801" xml:space="preserve">c’eſt ainſi qu’on a fait le <lb/>Periſtile du Louvre dont j’ai parlé &</s> <s xml:id="echoid-s10802" xml:space="preserve">, quoi qu’il y ait peu d’exem- <pb o="57" file="0519" n="567" rhead="LIVRE V. DE LA DE’CORATION."/> ples antiques où cela ait été pratiqué, on a trouvé que les Colon-<lb/>nates dans ce goût-la réuſſiſſoient ſi bien, qu’il n’y a preſque point <lb/>de Bâtiment conſiderable où il n’y en ait.</s> <s xml:id="echoid-s10803" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10804" xml:space="preserve">Les Colomnes couplées n’ont ordinairement qu’un Piédeſtal com-<lb/>mun, parce que devant être autant près l’une de l’autre qu’il eſt poſ-<lb/>ſible, ſi l’on vouloit que leurs Piédeſtaux fuſſent ſeparés, les Corni-<lb/>ches & </s> <s xml:id="echoid-s10805" xml:space="preserve">les Baſes de ces Piédeſtaux ſe trouveroient confondus en-<lb/>ſemble, ce qui feroit un méchant effet. </s> <s xml:id="echoid-s10806" xml:space="preserve">Cependant, ſi les deux Co-<lb/>lomnes pouvoient être aſſés éloignées l’une de l’autre pour ne pas <lb/>mêler les Corniches & </s> <s xml:id="echoid-s10807" xml:space="preserve">les Baſes des Piédeſtaux, elles pourroient <lb/>avoir chacune le leur, ce qui eſt quelquefois neceſſaire comme <lb/>quand deux Colomnes ſont élevées ſur deux autres, parce qu’alors <lb/>il eſt à propos de rendre les Piédeſtaux legers.</s> <s xml:id="echoid-s10808" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10809" xml:space="preserve">Quand il y a pluſieurs Colomnes de file à une égale diſtance, <lb/>ou même quand elles ſont couplées, on leur donne encore un eſpe-<lb/>ce de Piédeſtal commun qui regne ſur toute la longueur du Periſtile <lb/>& </s> <s xml:id="echoid-s10810" xml:space="preserve">n’eſt qu’à hauteur d’apui: </s> <s xml:id="echoid-s10811" xml:space="preserve">& </s> <s xml:id="echoid-s10812" xml:space="preserve">l’intervale qu’il y a d’une Colomne <lb/>à l’autre ſe remplit par une baluſtrade qui lie enſemble toutes les <lb/>parties qui ſervent de ſoubaſſement.</s> <s xml:id="echoid-s10813" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10814" xml:space="preserve">La régle la plus génerale que l’on ſuit aux Arcades des Portiques <lb/>eſt de leur donner pour hauteur deux fois leur largeur, & </s> <s xml:id="echoid-s10815" xml:space="preserve">c’eſt ce <lb/>que Vignole fait aux Arcades de l’Ordre Toſcan, Dorique, & </s> <s xml:id="echoid-s10816" xml:space="preserve">Ioni-<lb/>que; </s> <s xml:id="echoid-s10817" xml:space="preserve">mais pour le Corinthien & </s> <s xml:id="echoid-s10818" xml:space="preserve">le Compoſite, il leur donne pour <lb/>hauteur un module de plus que le double de leur largeur; </s> <s xml:id="echoid-s10819" xml:space="preserve">cependant <lb/>comme les Colomnes qui accompagnent ces Arcades apportent <lb/>quelque changement à leur largeur, parce qu’elle ſe fait plus grande <lb/>quand il y a des Piédeſtaux aux Colomnes que quand il n’y en a <lb/>point, voici encore ce que Vignole preſcrit pour ces deux cas.</s> <s xml:id="echoid-s10820" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10821" xml:space="preserve">Dans l’Ordre Toſcan, quand il n’y a point de Piédeſtaux aux Co-<lb/>lomnes, il faut donner 6 modules & </s> <s xml:id="echoid-s10822" xml:space="preserve">demi de largeur aux Arcades <lb/>& </s> <s xml:id="echoid-s10823" xml:space="preserve">3 à leurs Jambages; </s> <s xml:id="echoid-s10824" xml:space="preserve">mais, quand les Colomnes ont des Piéde-<lb/>ſtaux, la largeur des Arcades ſe fait de 3 modules 3 quarts, & </s> <s xml:id="echoid-s10825" xml:space="preserve">celle <lb/>des Jambages de quatre.</s> <s xml:id="echoid-s10826" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10827" xml:space="preserve">Dans le Dorique ſans Piédeſtaux, il faut donner 7 modules de <lb/>largeur aux Arcades & </s> <s xml:id="echoid-s10828" xml:space="preserve">3 à leurs Jambages; </s> <s xml:id="echoid-s10829" xml:space="preserve">& </s> <s xml:id="echoid-s10830" xml:space="preserve">quand il y a des Pié-<lb/>deſtaux, la largeur des Arcades ſe fait de 10 modules & </s> <s xml:id="echoid-s10831" xml:space="preserve">celles des <lb/>Jambages de cinq.</s> <s xml:id="echoid-s10832" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10833" xml:space="preserve">Dans l’Ionique ſans Piédeſtaux, la largeur des Arcades doit être <lb/>de 8 modules & </s> <s xml:id="echoid-s10834" xml:space="preserve">demi, & </s> <s xml:id="echoid-s10835" xml:space="preserve">celle des Jambages de 3; </s> <s xml:id="echoid-s10836" xml:space="preserve">& </s> <s xml:id="echoid-s10837" xml:space="preserve">quand il y <lb/>a des Piédeſtaux, il faut 11 modules de largeur aux Arcades & </s> <s xml:id="echoid-s10838" xml:space="preserve">3 <lb/>aux Jambages.</s> <s xml:id="echoid-s10839" xml:space="preserve"/> </p> <pb o="58" file="0520" n="568" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s10840" xml:space="preserve">Enfin aux Ordres Corinthien & </s> <s xml:id="echoid-s10841" xml:space="preserve">Cempoſite ſans Piédeſtaux, il <lb/>faut donner 9 modules à la largeur des Arcades & </s> <s xml:id="echoid-s10842" xml:space="preserve">3 à celle des Jam-<lb/>bages; </s> <s xml:id="echoid-s10843" xml:space="preserve">& </s> <s xml:id="echoid-s10844" xml:space="preserve">quand il y a des Piédeſtaux, la largeur des Arcades ſe <lb/>fait de 12 modules, & </s> <s xml:id="echoid-s10845" xml:space="preserve">celle des Jambages de trois.</s> <s xml:id="echoid-s10846" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10847" xml:space="preserve">Quand les Colomnes ſont engagées dans les Jambages, Vignole <lb/>veut dans tous les Ordres que la partie engagée ne ſoit que les 3 <lb/>quarts du demi-diamêtre. </s> <s xml:id="echoid-s10848" xml:space="preserve">Scamozzy ne ſuit pas tout-à-fait cette <lb/>régle, voulant que la Colomne ſorte au juſte des 3 quarts de ſon <lb/>diamêtre.</s> <s xml:id="echoid-s10849" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10850" xml:space="preserve">Comme il arrive ſouvent qu’on fait des Arcades ſans Colomne <lb/>ni Pilaſtre, il eſt bon d’obſerver qu’il faut autant qu’il eſt poſſible <lb/>donner à leurs Jambages les mêmes proportions que s’il y en avoit, <lb/>& </s> <s xml:id="echoid-s10851" xml:space="preserve">de ne jamais faire les Jambages plus larges que la moitié de l’Ar-<lb/>cade, ni plus étroit que le tiers, & </s> <s xml:id="echoid-s10852" xml:space="preserve">que les Bayes ſoient toûjours <lb/>plus grandes aux ordres maſſifs qu’aux plus délicats.</s> <s xml:id="echoid-s10853" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10854" xml:space="preserve">Pour empêcher que la ligne courbe de l’Arcade, en venant join-<lb/>dre la ligne à plomb de l’Alette, ne paroiſſe faire un jarret ou cou-<lb/>de, on termine les piédroits par une impoſte, qui n’eſt autre choſe <lb/>qu’une petite Corniche dont la ſaillie ne doit point exceder les Pi-<lb/>laſtres quand il y en a aux Jambages, ni la rondeur ou le plus <lb/>gros des Colomnes; </s> <s xml:id="echoid-s10855" xml:space="preserve">& </s> <s xml:id="echoid-s10856" xml:space="preserve">c’eſt ce que Vignole a parfaitement bien <lb/>obſervé dans les deſſeins des impoſtes qu’il a donnez pour tous les <lb/>Ordres, n’ayant pas ſuivi la plûpart des Bâtimens antiques, où elles <lb/>ont une ſigrande ſaillie, qu’elles ſemblent être plûtôt des Corniches <lb/>d’Entablement, que des Couſſinets pour recevoir la retombée des <lb/>Arcades avec leurs Bandeaux ou Archivoltes.</s> <s xml:id="echoid-s10857" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10858" xml:space="preserve">Selon Scamozzy, les impoſtes des grandes Arcades, dont les Co-<lb/>lomnes ne portent que ſur des Socles ſans Piédeſtaux, doivent avoir <lb/>de hauteur une treiziéme partie & </s> <s xml:id="echoid-s10859" xml:space="preserve">demi de celle des Jambages: </s> <s xml:id="echoid-s10860" xml:space="preserve">il <lb/>ajoûte que les Bandeaux de l’Arc, ou Archivolte, ne doivent ja-<lb/>mais avoir pour l’Ordre Toſcan plus de largeur que la neuviême <lb/>partie de celle de l’Arcade, & </s> <s xml:id="echoid-s10861" xml:space="preserve">la dixiéme pour le Corinthien, ainſi <lb/>entre ces deux proportions pour les autres Ordres. </s> <s xml:id="echoid-s10862" xml:space="preserve">A l’égard du <lb/>Boſſage de la clef qui excede le Bandeau de l’Arc, ſuivant le mê-<lb/>me Architecte, il le faut faire au moins de 2 tiers de modules, ou <lb/>au plus d’un module, obſervant de lui donner moins de hauteur <lb/>aux Ordres ſimples, & </s> <s xml:id="echoid-s10863" xml:space="preserve">de l’augmenter à proportion aux Ordres dé-<lb/>licats: </s> <s xml:id="echoid-s10864" xml:space="preserve">Ces Boſſages peuvent recevoir des ornemens conformes à <lb/>l’uſage du Bâtiment, comme des Conſoles, des Têtes d’Animaux, <lb/>des Maſques, des Caſques, &</s> <s xml:id="echoid-s10865" xml:space="preserve">c.</s> <s xml:id="echoid-s10866" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10867" xml:space="preserve">Pour donner quelque exemple de tout ce que nous venons d’en- <pb file="0521" n="569"/> <pb file="0522" n="570"/> <pb file="0522a" n="571"/> <anchor type="figure" xlink:label="fig-0522a-01a" xlink:href="fig-0522a-01"/> <pb file="0523" n="572"/> <pb file="0524" n="573"/> <pb file="0524a" n="574"/> <anchor type="figure" xlink:label="fig-0524a-01a" xlink:href="fig-0524a-01"/> <pb o="59" file="0525" n="575" rhead="LIVRE V. DE LA DE’CORATION."/> feigner, on peut conſiderer un Portique Dorique repreſenté ſur la <lb/> <anchor type="note" xlink:label="note-0525-01a" xlink:href="note-0525-01"/> 50<emph style="sub">e</emph> Planche, par lequel on pourra juger de ceuxdes autres Ordres: <lb/></s> <s xml:id="echoid-s10868" xml:space="preserve">on verra de même ſur la Plance 51 un autre Portique ſuivant l’Or-<lb/>dre Ionique, tiré des Edifices antiques de Rome, raporté par Mr. </s> <s xml:id="echoid-s10869" xml:space="preserve"><lb/>de Chambray, qui en parle comme du plus noble & </s> <s xml:id="echoid-s10870" xml:space="preserve">du plus magni-<lb/>fique morceau qu’on puiſſe voir; </s> <s xml:id="echoid-s10871" xml:space="preserve">il conviendra d’autant mieux ici, <lb/>qu’on y verra l’aſſemblage de toutes les parties d’une ordonnance.</s> <s xml:id="echoid-s10872" xml:space="preserve"/> </p> <div xml:id="echoid-div471" type="float" level="2" n="1"> <figure xlink:label="fig-0522a-01" xlink:href="fig-0522a-01a"> <image file="0522a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0522a-01"/> </figure> <figure xlink:label="fig-0524a-01" xlink:href="fig-0524a-01a"> <image file="0524a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0524a-01"/> </figure> <note position="right" xlink:label="note-0525-01" xlink:href="note-0525-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>50 & 51.</note> </div> <p> <s xml:id="echoid-s10873" xml:space="preserve">A l’égard des moulures & </s> <s xml:id="echoid-s10874" xml:space="preserve">des autres ornemens qu’on peut don-<lb/>ner aux impoſtes & </s> <s xml:id="echoid-s10875" xml:space="preserve">aux Archivoltes des Arcades ſuivant les Or-<lb/> <anchor type="note" xlink:label="note-0525-02a" xlink:href="note-0525-02"/> dres, on en peut voir des modeles ſur la Plance 42: </s> <s xml:id="echoid-s10876" xml:space="preserve">par exemple, <lb/>les Figures 2 & </s> <s xml:id="echoid-s10877" xml:space="preserve">3. </s> <s xml:id="echoid-s10878" xml:space="preserve">pourront ſervir pour les Arcades faites ſelon <lb/>l’Ordre Toſcan, la 7<emph style="sub">e</emph> pour le Dorique, la 8<emph style="sub">e</emph> pour l’Ionique, la <lb/>premiere pour le Corinthien & </s> <s xml:id="echoid-s10879" xml:space="preserve">la 6<emph style="sub">e</emph> pour le Compoſite, les ayant <lb/>deſſinées d’après Vignole; </s> <s xml:id="echoid-s10880" xml:space="preserve">pour ce qui eſt des nombres qui en dé-<lb/>terminent les proportions, ils expriment des parties de module, <lb/>ſelon que le module eſt diviſé en 12 ou en 18 parties égales par <lb/>raport à l’Ordre dont il s’agit.</s> <s xml:id="echoid-s10881" xml:space="preserve"/> </p> <div xml:id="echoid-div472" type="float" level="2" n="2"> <note position="right" xlink:label="note-0525-02" xlink:href="note-0525-02a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>42.</note> </div> <p> <s xml:id="echoid-s10882" xml:space="preserve">Pour dire auſſi quelque choſe des Niches, que l’on creuſe dans <lb/>les murs pour y placer agréablement quelques Statues, l’on ſaura <lb/>que leur plus belle proportion eſt de leur donner pour hauteur 2 <lb/>fois & </s> <s xml:id="echoid-s10883" xml:space="preserve">demi leur largeur: </s> <s xml:id="echoid-s10884" xml:space="preserve">ainſi, voulant faire une niche de 3 pieds de <lb/>large, on donnera 6 pieds depuis le bas juſqu’à la naiſſance du de-<lb/>mi-cercle du cul-de-four qui termine le haut de la niche; </s> <s xml:id="echoid-s10885" xml:space="preserve">& </s> <s xml:id="echoid-s10886" xml:space="preserve">com-<lb/>me la hauteur de ce demi-cercle ſe trouvera d’un pied & </s> <s xml:id="echoid-s10887" xml:space="preserve">demi, <lb/>celle de toute la niche ſera de 7 pieds & </s> <s xml:id="echoid-s10888" xml:space="preserve">demi, c’eſt-à-dire de 2 <lb/>fois & </s> <s xml:id="echoid-s10889" xml:space="preserve">demi ſa largeur: </s> <s xml:id="echoid-s10890" xml:space="preserve">pour ce qui eſt de l’enfoncement de la Ni-<lb/>che, il ſe fait preſque toûjours d’un demi-cercle, dont le diamêtre <lb/>eſt égal à celui de la largeur de la Niche même.</s> <s xml:id="echoid-s10891" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10892" xml:space="preserve">Souvent les Niches ont une impoſte & </s> <s xml:id="echoid-s10893" xml:space="preserve">une Archivolte: </s> <s xml:id="echoid-s10894" xml:space="preserve">la lar-<lb/>geur de l’Archivolte ſe fait de la 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s10895" xml:space="preserve">ou 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s10896" xml:space="preserve">partie de l’ouverture de la <lb/>Niche, & </s> <s xml:id="echoid-s10897" xml:space="preserve">celle de I’impoſte de la 5<emph style="sub">e</emph>. </s> <s xml:id="echoid-s10898" xml:space="preserve">ou 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s10899" xml:space="preserve">partie de la même ou-<lb/>verture; </s> <s xml:id="echoid-s10900" xml:space="preserve">l’une & </s> <s xml:id="echoid-s10901" xml:space="preserve">l’autre doivent être compoſées de moulures qui <lb/>ayent raport à l’Architecture du lieu: </s> <s xml:id="echoid-s10902" xml:space="preserve">mais, ſi la Niche étoit placée <lb/>au-deſſous d’une impoſte, entre deux Colomnes ou Pilaſtres, alors <lb/>elle ne doit point en avoir; </s> <s xml:id="echoid-s10903" xml:space="preserve">parce que deux impoſtes l’une au-deſſus <lb/>de l’autre font un méchant effet: </s> <s xml:id="echoid-s10904" xml:space="preserve">il ne faut pas non plus mettre de <lb/>Niches entre les Pilaſtres, s’ils ne ſont éloignés l’un de l’autre de <lb/>près d’un tiers de leur hauteur; </s> <s xml:id="echoid-s10905" xml:space="preserve">autrement elles ſeroient trop petites <lb/>& </s> <s xml:id="echoid-s10906" xml:space="preserve">trop étroites: </s> <s xml:id="echoid-s10907" xml:space="preserve">à l’égard de l’élevation des Niches, le bas doit ré-<lb/>pondre au niveau des Corniches des Piédeſtaux des Pilaſtres ou <lb/>Colomnes qui les accompagnent.</s> <s xml:id="echoid-s10908" xml:space="preserve"/> </p> <pb o="60" file="0526" n="576" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s10909" xml:space="preserve">Comme il doit regner une proportion entre la hauteur des Ni-<lb/>ches & </s> <s xml:id="echoid-s10910" xml:space="preserve">celle des Figures qu’on veut y placer, on obſervera de po-<lb/>ſer la Figure ſur un Socle, dont l’élevation ſoit égale à la moitié de <lb/>la hauteur de la tête de la Figure, & </s> <s xml:id="echoid-s10911" xml:space="preserve">que le menton de cette Figure <lb/>réponde à peu-près au niveau de l’impoſte de la Niche: </s> <s xml:id="echoid-s10912" xml:space="preserve">ainſi la Fi-<lb/>gure ayant 6 pieds, ſi on en ôte 9 pouces pour la hauteur de la tête <lb/>qui en eſt ordinairement la 8<emph style="sub">e</emph>. </s> <s xml:id="echoid-s10913" xml:space="preserve">partie, il reſtera 5 pieds 3 pouces <lb/>pour la hauteur du Socle, on aura 5 pieds 8 pouces pour celle de <lb/>la Niche juſqu’à l’impoſte, & </s> <s xml:id="echoid-s10914" xml:space="preserve">2 pieds 10 pouces pour ſa largeur, <lb/>c’eſt pourquoi la hauteur ſous la clef ſera de 7 pieds un pouce. </s> <s xml:id="echoid-s10915" xml:space="preserve">Si <lb/>la Figure avoit 9 pieds, on trouvera par la même régle que la hau-<lb/>teur de la Niche ſous la clef ſera de 10 pieds 6 pouces. </s> <s xml:id="echoid-s10916" xml:space="preserve">On peut <lb/>donc de-là tirer une regle pour la proportion de la hauteur des Ni-<lb/>ches avec celle des Figures, qui eſt d’ajoûter à la hauteur de la <lb/>Figure, autant de fois 2 pouces qu’elle a de pieds, ainſi pour une <lb/>Figure de 5 pieds, la Niche doit être haute de 5 pieds 10 pouces.</s> <s xml:id="echoid-s10917" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div474" type="section" level="1" n="127"> <head xml:id="echoid-head341" xml:space="preserve">CHAPITRE ONZIE’ ME. <lb/>De l’Aſſemblage des Ordres, ou de pluſieurs Ordres mis les <lb/>uns ſur les autres.</head> <p> <s xml:id="echoid-s10918" xml:space="preserve">QUAND on veut décorer un Edifice de conſequence par <lb/>pluſieurs Ordres d’Architecture differens, poſés les uns ſur les <lb/>autres, on doit obſerver pour régle génerale que le fort por-<lb/>te foible, c’eſt-à-dire que l’Ordre ſuperieur ſoit toûjours plus déli-<lb/>cat que l’inferieur: </s> <s xml:id="echoid-s10919" xml:space="preserve">ainſi, il faut que le Toſcan ſoit ſous le Dorique, <lb/>le Dorique ſous l’Ionique, l’Ionique ſous le Corinthien, & </s> <s xml:id="echoid-s10920" xml:space="preserve">le Corin-<lb/>thien ſous le Compoſite; </s> <s xml:id="echoid-s10921" xml:space="preserve">en ſorte que les Axes des Colomnes ſe <lb/>rencontrent toûjours en même aplomb.</s> <s xml:id="echoid-s10922" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10923" xml:space="preserve">Lorſque les Colomnes ſont entierement iſolées, & </s> <s xml:id="echoid-s10924" xml:space="preserve">qu’elles por-<lb/>tent tout le poids de l’Entablement, la régle de Vitruve eſt que <lb/>celles du ſecond Ordre ſoient toûjours un quart moindre en groſ-<lb/>ſeur que celles du premier, & </s> <s xml:id="echoid-s10925" xml:space="preserve">celles du troiſiéme un quart moindre <lb/>que celles du ſecond; </s> <s xml:id="echoid-s10926" xml:space="preserve">parce que, dit-il, il eſt juſte que ce qui porte <lb/>ſoit plus fort que ce qui doit être porté, & </s> <s xml:id="echoid-s10927" xml:space="preserve">d’ailleurs pour imiter <lb/>les Arbres dont la groſſeur diminue toûjours à meſure que la tige <lb/>s’éloigne de la racine.</s> <s xml:id="echoid-s10928" xml:space="preserve"/> </p> <pb o="61" file="0527" n="577" rhead="LIVRE V. DE LA DE’CORATION."/> <p> <s xml:id="echoid-s10929" xml:space="preserve">Ce qui nous eſt reſté des Monumens antiques nes’éloigne guére <lb/>de cette régle, dit Mr. </s> <s xml:id="echoid-s10930" xml:space="preserve">Blondel; </s> <s xml:id="echoid-s10931" xml:space="preserve">car les Colomnes du ſecond Ordre <lb/>du Portique de la Scene qui eſt au Théatre de Pole en Dalmatie <lb/>ſont les trois quarts de celles de deſſous; </s> <s xml:id="echoid-s10932" xml:space="preserve">celles du troiſiéme Ordre <lb/>du Settizone de Severe étoient auſſi les trois quarts de celles du <lb/>ſecond: </s> <s xml:id="echoid-s10933" xml:space="preserve">mais celles du ſecond Ordre étoient plus hautes à l’égard de <lb/>celles du premier; </s> <s xml:id="echoid-s10934" xml:space="preserve">car celles-ci ne ſurpaſſoient les Colomnes du <lb/>milieu que d’une 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s10935" xml:space="preserve">partie, c’eſt-à-dire que la hauteur des Colom-<lb/>nes de deſſous étoit à celles des Colomnes du milieu comme 6 <lb/>à 5.</s> <s xml:id="echoid-s10936" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10937" xml:space="preserve">Scamozzy blâme cette régle de Vitruve, diſant qu’elle n’eſt fon-<lb/>dée ſur aucune raiſon: </s> <s xml:id="echoid-s10938" xml:space="preserve">il veut que les Colomnes de deſſus pren-<lb/>nent la meſure de leur groſſeur ſur celles de deſſous, c’eſt-à-dire <lb/>que la groſſeur du pied de la Colomne ſuperieure doit être la même <lb/>que celle du haut de la Colomne inferieure, comme ſi les Colomnes <lb/>des differens Ordres provenoient d’un grand Arbre coupé par piéces, <lb/>dont les morceaux étant poſés les uns ſur les autres ſuivroient leur <lb/>diminution naturelle.</s> <s xml:id="echoid-s10939" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10940" xml:space="preserve">Serlio donne auſſi pour régle générale aux ordonnances que l’on <lb/>doit mettre l’une ſur l’autre, que la ſuperieure ſoit toûjours les trois <lb/>quarts de celle ſur laquelle elle poſe immédiatement, excepté aux <lb/>Edifices qui ont un ruſtique nud pour premiere ordonnance, parce <lb/>qu’il eſt à propos que celle qui eſt au-deſſus lui ſoit égale; </s> <s xml:id="echoid-s10941" xml:space="preserve">car autre-<lb/>ment les ordonnances plus hautes paroîtroient trop petites, & </s> <s xml:id="echoid-s10942" xml:space="preserve">le <lb/>ruſtique ſeroit trop élevé à proportion du reſte: </s> <s xml:id="echoid-s10943" xml:space="preserve">les Ordonnances <lb/>de cet Auteur ſont toutes avec Piédeſtal, ou toutes ſans Piédeſtal, <lb/>afin que les ſuperieures étant diviſées en même proportion que les <lb/>inferieures, les Colomnes & </s> <s xml:id="echoid-s10944" xml:space="preserve">les Entablemens de deſſus ſe trou-<lb/>vent toûjours les trois quarts de l’étage de deſſous.</s> <s xml:id="echoid-s10945" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10946" xml:space="preserve">Sans m’arrêter à raporter les differentes régles que les Architec-<lb/>tes ont données pour la compoſition des ordonnances des Colomnes <lb/>qui doivent être miſes les unes ſur les autres, nous nous en tiendrons <lb/>à celle de Scamozzy qui me paroît bien entenduë: </s> <s xml:id="echoid-s10947" xml:space="preserve">c’eſt pourquoi <lb/>je dirai une fois pour tout, que lorſqu’on voudra mettre deux Or-<lb/>dres l’un ſur l’autre, il faut, après avoir déterminé la diminution de <lb/>la Colomne de l’Orde inferieur, ſe ſervir du demi-diamêtre du haut <lb/>du Fuſt pour le module qui doit régler l’ordonnance ſuperieure; </s> <s xml:id="echoid-s10948" xml:space="preserve">par <lb/>exemple, voulant mettre le Corinthien ſur l’Ionique, ayant vû dans <lb/>le troiſiéme Chapitre que la Colomne Ionique ſelon Vignole devoit <lb/>diminuer par le haut de 3 parties de chaque côté, enſorte que le <lb/>diamêtre du ſommet du Fuſt ſoit réduit à un module 12 parties, <pb o="62" file="0528" n="578" rhead="LA SCIENCE DES INGENIEURS,"/> il faut faire une ligne égale à la moitié de cette quantité, c’eſt-à-<lb/>dire qui vaille 15 parties, & </s> <s xml:id="echoid-s10949" xml:space="preserve">s’en ſervir pour le module qui doit ré-<lb/>gler l’Ordre Corinthien, après toutesfois qu’on l’aura diviſé en 18 <lb/>parties égales, afin de ſe conformer aux meſures dont Vignole ſe <lb/>ſert pour cet Ordre: </s> <s xml:id="echoid-s10950" xml:space="preserve">de même, voulant mettre un troiſiéme Ordre <lb/>ſur les deux précédens, c’eſt-à-dire le Compoſite ſur le Corinthien, <lb/>l’on verra que la Colomne Corinthienne devant diminuer de façon <lb/>que le demi-diamêtre qui eſt de 16 parties par le bas ſoit réduit à 15 <lb/>par le haut, on ſe ſervira encore de ce demi-diamêtre réduit pour <lb/>le module qui doit régler la troiſiéme ordonnance.</s> <s xml:id="echoid-s10951" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10952" xml:space="preserve">La régle précédente ne doit pourtant pas être regardée comme ſi <lb/>générale, qu’on ne puiſſe s’en écarter quelquefois: </s> <s xml:id="echoid-s10953" xml:space="preserve">car il arrive aſſez <lb/>ſouvent qu’on eſt obligé d’aſſujettir la hauteur des Colomnes à celle <lb/>des étages, auſſi-bien qu’à la difference de leurs Ordres; </s> <s xml:id="echoid-s10954" xml:space="preserve">car tantôt <lb/>il faut avoir égard à la proportion que la hauteur d’un façade doit <lb/>avoir avec ſa largeur, tantôt à la hauteur de l’Edifice même; </s> <s xml:id="echoid-s10955" xml:space="preserve">car à <lb/>ceux qui ſont fort élevés, le grand éloignement de la vûë peut al-<lb/>terer conſiderablement les meſures ordinaires & </s> <s xml:id="echoid-s10956" xml:space="preserve">les rendre differen-<lb/>tes de celles dont on fe ſerviroit dans les diſtances moins éloignées: </s> <s xml:id="echoid-s10957" xml:space="preserve">& </s> <s xml:id="echoid-s10958" xml:space="preserve"><lb/>c’eſt ſans doute pour cette raiſon, dit Mr. </s> <s xml:id="echoid-s10959" xml:space="preserve">Blondel, que l’Architecte du <lb/>Coliſée a donné plus de hauteur au Pilaſtre du dernier Ordre, qu’aux <lb/>Colomnes Corinthienes du troiſiéme, & </s> <s xml:id="echoid-s10960" xml:space="preserve">à celles-ci plus de hauteur <lb/>qu’aux Colomnes Ioniques du ſecond; </s> <s xml:id="echoid-s10961" xml:space="preserve">car, après avoir diſpoſé les <lb/>deux premiers Ordres, de maniere que les Colomnes Doriques du <lb/>deſſous fuſſent plus hautes que les Ioniques dans le raport de 38 à <lb/>35. </s> <s xml:id="echoid-s10962" xml:space="preserve">qu’il a pris comme celui qui répondoit aſſez juſte à leur éleva-<lb/>tion, c’eſt-à-dire à la diſtance d’où elles devoient être vûës, il a <lb/>fait celles du troiſiéme Ordre plus hautes que celles du ſecond, dans <lb/>la raiſon de 37 à 35, & </s> <s xml:id="echoid-s10963" xml:space="preserve">celles du dernier Ordre encore plus hau-<lb/>tes que celles du troiſiéme, dans la raiſon de 38 à 37, parce qu’il a <lb/>crû que ces hauteurs, dans un ſi grand éloignement, ſeroient rai-<lb/>ſonnablement diminuées pour produire un bon effet aux yeux des <lb/>Spectateurs.</s> <s xml:id="echoid-s10964" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10965" xml:space="preserve">La difficulté de bien déterminer les groſſeurs des Colomnes que <lb/>l’on met les unes ſur les autres vient de la rigidité de cette régle <lb/>d’Architecture qui ne ſouffre pas qu’il y ait aucune charge dans le <lb/>Bâtiment, qui porte à faux; </s> <s xml:id="echoid-s10966" xml:space="preserve">& </s> <s xml:id="echoid-s10967" xml:space="preserve">comme elle veut que la Plinthe de <lb/>la Baſe d’une Colomne réponde au vif du Dé du Piédeſtal ſur le-<lb/>quel elle eſt aſſiſe, que l’Architrave réponde au vif du haut de la <lb/>Colomne, & </s> <s xml:id="echoid-s10968" xml:space="preserve">la Friſe à celui de l’Architrave, auſſi-bien que le <lb/>nud du Timpan du Frontiſpice, il faudroit ſur ce principe que la <pb o="63" file="0529" n="579" rhead="LIVRE V. DE LA DE’CORATION."/> Plinthe de la Baſe du ſecond étage, au cas qu’elle ſe trouvât poſée <lb/>immédiatement ſur la Corniche du premier, répondit au vif du <lb/>haut de la Colomne de deſſous, & </s> <s xml:id="echoid-s10969" xml:space="preserve">que les membres que l’on vou-<lb/>droit mettre entre-deux, ſoit Socle, ſoit Piédeſtal, fuſſent ſitués de <lb/>même. </s> <s xml:id="echoid-s10970" xml:space="preserve">Mais, ſi l’on donne à toutes ces parties la ſaillie qui leur con-<lb/>vient ſuivant la nature de leur Ordre, il arrive, ou que le vif de la <lb/>Colomne de deſſous ſe trouve le plus ſouvent reculé en arriere <lb/>& </s> <s xml:id="echoid-s10971" xml:space="preserve">en retraite hors de l’aplomb de celui de la Colomne de deſſous, <lb/>ou que ſon diamêtre eſt tellement diminué, que la Colomne de-<lb/>vient hors de meſure, ce qui preſente bien des difficultés qu’il <lb/>n’eſt pas aiſé de ſurmonter.</s> <s xml:id="echoid-s10972" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10973" xml:space="preserve">L’Architecte du Coliſée, dit Mr. </s> <s xml:id="echoid-s10974" xml:space="preserve">Blondel, ne s’eſt pas ſoucié <lb/>que les Colomnes ſuperieures fuſſent aplomb ſur celles de deſſous; <lb/></s> <s xml:id="echoid-s10975" xml:space="preserve">au contraire, il les a reculées de beaucoup en arriere, les poſant <lb/>ſur les retraites du corps du mur, & </s> <s xml:id="echoid-s10976" xml:space="preserve">par ce moyen il a eu toute <lb/>la facilité poſſible pour que rien ne porte à faux.</s> <s xml:id="echoid-s10977" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10978" xml:space="preserve">Nous avons un exemple de cette pratique, dit-il encore, au <lb/>Portail de l’Egliſe S. </s> <s xml:id="echoid-s10979" xml:space="preserve">Loüis des PP. </s> <s xml:id="echoid-s10980" xml:space="preserve">Jeſuites de la Ruë S. </s> <s xml:id="echoid-s10981" xml:space="preserve">Antoine <lb/>à Paris, où les Colomnes des Ordres ſuperieurs ſe retirent par de-<lb/>gré en dedans; </s> <s xml:id="echoid-s10982" xml:space="preserve">ce qui ne paroît point de front, mais ſeulement <lb/>lorſqu’on les regarde de profil: </s> <s xml:id="echoid-s10983" xml:space="preserve">& </s> <s xml:id="echoid-s10984" xml:space="preserve">cela, ſuivant le ſentiment de <lb/>quelques Modernes, fait un méchant effet à la vûe.</s> </p> <p> <s xml:id="echoid-s10985" xml:space="preserve">Ces mêmes Architectes, pour éviter ces embarras, ſont d’avis <lb/>que l’on ne mette jamais de Piédeſtaux dans les Ordonnances ſu-<lb/>perieures, mais ſeulement des Socles ſous les Baſes des Colom-<lb/>nes, ce qui eſt contraire à la doctrine de Vitruve, qui met des <lb/>Piédeſtaux dans toutes les ordonnances de la Scene deſon Théâ-<lb/>tre & </s> <s xml:id="echoid-s10986" xml:space="preserve">par tout ailleurs, & </s> <s xml:id="echoid-s10987" xml:space="preserve">à la pratique de Anciens dont il y a <lb/>peu d’exemples de Colomnes poſéesl’une ſur l’autre ſans Piédeſtal: <lb/></s> <s xml:id="echoid-s10988" xml:space="preserve">les Architectes modernes s’en ſervent preſque toûjours pour <lb/>marquer la hauteur des appuis des Arcs ou des Fenêtres qui ſont <lb/>dans les Entre-Colomnes des Ordres ſuperieurs.</s> </p> <p> <s xml:id="echoid-s10989" xml:space="preserve">N’ayant rien trouvé d’aſſés précis dans les Auteurs pour ſavoir <lb/>quel parti prendre dans le choix de tout ce qui a été dit & </s> <s xml:id="echoid-s10990" xml:space="preserve">executé <lb/>au ſujet de la Compoſition des Ordres, je ſuis obligé de convenir <lb/>que cette partie de la Décoration eſt très-difficile, & </s> <s xml:id="echoid-s10991" xml:space="preserve">demande bien <lb/>des connoiſſances qui ne peuvent guére être dévelopées dans un <lb/>Traité auſſi abrégé que celui-ci: </s> <s xml:id="echoid-s10992" xml:space="preserve">c’eſt pourquoi, tout ce que je puis <lb/>faire de mieux eſt d’inſinuer quelques Obſervations generales; </s> <s xml:id="echoid-s10993" xml:space="preserve">laiſ-<lb/>ſant à ceux, qui voudront s’appliquer particulierement à l’Archîtec-<lb/>ture, de s’inſtruire plus à fond par la lecture des bons Auteurs, &</s> <s xml:id="echoid-s10994" xml:space="preserve"> <pb o="64" file="0530" n="580" rhead="LA SCIENCE DES INGENIEURS,"/> l’examen des Edifices les plus aprouvés, qui eſt à la verité un tra-<lb/>vail plus grand qu’on ne penſe, ſi j’en juge par ce que m’a coûté le <lb/>peu d’acquis que j’ai dans ce genre d’étude.</s> <s xml:id="echoid-s10995" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s10996" xml:space="preserve">Il ne paroît pas qu’on doive mettre plus de trois Ordres de Co-<lb/>lomnes l’un ſur l’autre; </s> <s xml:id="echoid-s10997" xml:space="preserve">car, outre qu’un quatriéme ſe trouveroit avoir <lb/>ſes Colomnes trop écartées pour leur hauteur, il ſeroit à craindre <lb/>que quatre étages de Colomnes ne fuſſent point aſſés ſolides: </s> <s xml:id="echoid-s10998" xml:space="preserve">ce-<lb/>pendant, on pourroit faire le premier étage ſelon un Ordre ruſtique <lb/>pour ſervir comme de ſoûbaſſement au premier des trois autres.</s> <s xml:id="echoid-s10999" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11000" xml:space="preserve">Quand on met pluſieurs Ordres de Pilaſtres les uns ſur les autres, <lb/>on rencontre moins de difficulté pour régler la compoſition des <lb/>ordonnances, que lorſqu’il s’agit des Colomnes, puiſqu’alors il <lb/>ſuffit d’avoir égard à la difference des étages, ſans que les ſaillies <lb/>contraignent à aucune ſujetion génante.</s> <s xml:id="echoid-s11001" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11002" xml:space="preserve">Les Pilaſtres étant de même largeur en haut qu’en bas, il ſemble <lb/>d’abord que la régularité voudroit que ceux qui ſont les uns ſur les <lb/>autres fuſſent auſſi de même largeur. </s> <s xml:id="echoid-s11003" xml:space="preserve">Mais, deux raiſons obligent à <lb/>faire le contraire: </s> <s xml:id="echoid-s11004" xml:space="preserve">la premiere eſt que les Ordres devant augmenter <lb/>en délicateſſe, les Pilaſtres doivent auſſi augmenter en hauteur par <lb/>raport à leur largeur. </s> <s xml:id="echoid-s11005" xml:space="preserve">Or, ſi le module demeuroit le même pour les <lb/>ſuperieurs comme pour les inferieurs, il s’enſuivroit que les Or-<lb/>dres & </s> <s xml:id="echoid-s11006" xml:space="preserve">les étages augmenteroient en hauteur à meſure qu’ils s’éle-<lb/>veroient les uns ſur les autres: </s> <s xml:id="echoid-s11007" xml:space="preserve">ce qui ne conviendroit point, ſur-<lb/>tout aux Façades qui n’ont point une grande élevation, & </s> <s xml:id="echoid-s11008" xml:space="preserve">dont l’œil <lb/>qui les regarde n’eſt pas fort éloigné des parties qui compoſent <lb/>l’ordonnance.</s> <s xml:id="echoid-s11009" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11010" xml:space="preserve">La ſeconde eſt que s’il y avoit des Colomnes avec des Pilaſtres, <lb/>comme cela arrive ſouvent, le diamêtre des Pilaſtres ſuperieurs ſe <lb/>trouveroit plus fort que celui du haut de la Colomne inferieure, <lb/>ce qui cauſeroit encore un autre défaut contraire à la bonne Ar-<lb/>chitecture.</s> <s xml:id="echoid-s11011" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11012" xml:space="preserve">Supoſant donc qu’on veuille mettre pluſieurs Ordres de Pilaſtres <lb/>les uns ſur les autres, je croi que la meilleure maniere eſt de com-<lb/>mencer d’abord par régler la hauteur de chaque Ordonnance ſelon <lb/>les maximes de Vitruve; </s> <s xml:id="echoid-s11013" xml:space="preserve">c’eſt-à-dire que l’étage ſuperieur ſoit toû-<lb/>jours les trois quarts de celui qui eſt immédiatement deſſous: </s> <s xml:id="echoid-s11014" xml:space="preserve">en-<lb/>ſuite on ſuivra ce qui eſt enſeigné dans le ſecond Chapitre page 14. <lb/></s> <s xml:id="echoid-s11015" xml:space="preserve">comme s’il étoit queſtion de Colomnes, & </s> <s xml:id="echoid-s11016" xml:space="preserve">alors le diamêtre des Co-<lb/>lomnes déterminera la largeur & </s> <s xml:id="echoid-s11017" xml:space="preserve">la hauteur des Pilaſtres, par con-<lb/>ſéquent la moitié de cette largeur, ou le demi-diamêtre deviendra <lb/>le module, qu’on n’aura plus qu’à diviſer en autant de parties égales <pb o="65" file="0531" n="581" rhead="LIVRE V. DE LA DE’CORATION."/> que le preſcrit Vignole pour l’Ordre dont il ſera queſtion: </s> <s xml:id="echoid-s11018" xml:space="preserve">ainſi il <lb/>ſera aiſé de régler toutes les parties de chaque Ordonnance.</s> <s xml:id="echoid-s11019" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11020" xml:space="preserve">Lorſque les Pilaſtres ſervent d’arriere-corps à des Colomnesiſo-<lb/>lées, il faut prendre garde que ces Pilaſtres ſoient aſſés éloignés <lb/>des Colomnes, pour empêcher que les Chapiteaux ne ſe confon-<lb/>dent comme au Portail de la Sorbonne.</s> <s xml:id="echoid-s11021" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11022" xml:space="preserve">Quand on veut décorer un Edifice, & </s> <s xml:id="echoid-s11023" xml:space="preserve">qu’on a des raiſons pour <lb/>lui donner un air deſolidité, il faut faire le premier étage d’un goût <lb/>ruſtique, ſur lequel on pourra élever un Ordre de Colomnes ou de <lb/>Pilaſtres, (car j’entens ici par premier étage celui du rez-de-Chauſ-<lb/>ſée,) ſurquoi il eſt à remarquer qu’on peut faire le ſecond étage plus <lb/>élevé que le premier, parce qu’alors le premier n’eſt regardé que <lb/>comme le ſoûbaſſement du ſecond: </s> <s xml:id="echoid-s11024" xml:space="preserve">mais, s’il s’agiſſoit d’un corps de <lb/>logis qu’on voulût faire plus élevé que les aîles qui doivent l’accom-<lb/>pagner, alors il ne faut pas que l’Ordre du rez-de-Chauſſée ſoit <lb/>plus élevé que celui des ailes; </s> <s xml:id="echoid-s11025" xml:space="preserve">mais il doit par-tout regner égale-<lb/>ment, & </s> <s xml:id="echoid-s11026" xml:space="preserve">ce ſera par le moyen d’un ſecond Ordre qu’on donnera <lb/>au corps de logis du commandement ſur les aîles.</s> <s xml:id="echoid-s11027" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11028" xml:space="preserve">Quand il y a des Appartemens qui tirent du jour ſous des Portiques <lb/>par des Croiſées qui ont un appuy, alors les Pilaſtres doivent avoir <lb/>des Piédeſtaux de la hauteur même des appuis, ou pour mieux dire <lb/>les Piédeſtaux doivent être continués & </s> <s xml:id="echoid-s11029" xml:space="preserve">ſervir d’appuis aux Croiſées; <lb/></s> <s xml:id="echoid-s11030" xml:space="preserve">mais ſi ces Croiſées n’avoient point d’appuis, & </s> <s xml:id="echoid-s11031" xml:space="preserve">qu’elles deſcendiſ-<lb/>ſent juſqu’au niveau du Parquet des Appartemens, alors il vaudroit <lb/>beaucoup mieux ne point donner de Piédeſtaux aux Pilaſtres.</s> <s xml:id="echoid-s11032" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11033" xml:space="preserve">On doit auſſi remarquer, que des Colomnes de differentes gran-<lb/>deurs ne doivent jamais ſe rencontrer à côté l’une de l’autre, ne <lb/>pouvant faire que des diſpoſitions très-déſagréables: </s> <s xml:id="echoid-s11034" xml:space="preserve">de même quand <lb/>on veut ajoûter quelques piéces à un Bâtiment déja fait, il faut <lb/>bien ſe garder de le faire d’un autre Ordre; </s> <s xml:id="echoid-s11035" xml:space="preserve">au contraire, il faut que <lb/>la piéce ajoûtée paroiſſe avoir été ordonnée par le même Architecte <lb/>qui a conduit le reſte du Bâtiment, & </s> <s xml:id="echoid-s11036" xml:space="preserve">pour tout dire enfin, il faut <lb/>que les parties ſe rapportent au tout autant qu’il eſt poſſible. </s> <s xml:id="echoid-s11037" xml:space="preserve">C’eſt <lb/>ce qui ne ſe rencontre pas bien exactement au Palais des Thuille-<lb/>ries du côté du Jardin: </s> <s xml:id="echoid-s11038" xml:space="preserve">la Façade, toute magnifique qu’elle paroiſſe, <lb/>eſt remplie de défauts inſuportables, parce qu’elle n’eſt compoſée <lb/>que de piéces ajoûtées, dont le tout ne réüſſit pas des mieux; </s> <s xml:id="echoid-s11039" xml:space="preserve">au <lb/>lieu que ce qui avoit été fait anciennement étoit un morceau ache-<lb/>vé dans ſon eſpece, avant qu’on l’eût accompagné de ce qui devoit <lb/>contribuer au deſſein general du Louvre.</s> <s xml:id="echoid-s11040" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11041" xml:space="preserve">Pour dire auſſi quelque choſe de l’Ordre Attique, qui eſt un pe- <pb o="66" file="0532" n="582" rhead="LA SCIENCE DES INGENIEURS,"/> tit Ordre toûjours élevé au-deſſus d’un plus grand, parce qu’il ſert <lb/>de dernier étage pour terminer le haut d’une Façade, il eſt bon <lb/>qu’on ſache qu’on ne lui donne ordinairement pour hauteur que le <lb/>tiers de l’Ordonnance du deſſous lorſqu’il n’y en a qu’une ſeule; <lb/></s> <s xml:id="echoid-s11042" xml:space="preserve">mais s’il s’en trouve pluſieurs, il peut avoir juſqu’à la moitié, & </s> <s xml:id="echoid-s11043" xml:space="preserve">mê-<lb/>me les deux tiers, de celle ſur laquelle il eſt immediatement aſſis.</s> <s xml:id="echoid-s11044" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11045" xml:space="preserve">L’ornement le plus ordinaire des Attiques ſe fait avec des Pi-<lb/>laſtres racourcis, que l’on nomme ainſi, parce que ces Pilaſtres <lb/>n’ayant pas moins de groſſeur qu’en ont par le haut les Colomnes <lb/>ou Pilaſtres qui ſont à l’Ordonnance de deſſous, leur hauteur ne peut <lb/>être aſſés grande pour ſe trouver conforme aux régles, puiſque le <lb/>plus ſouvent ils n’ont tout au plus que 5 ou 6 fois leur groſſeur com-<lb/>pris la Baſe & </s> <s xml:id="echoid-s11046" xml:space="preserve">le Chapiteau. </s> <s xml:id="echoid-s11047" xml:space="preserve">Leur Baſe ſe fait comme à l’ordi-<lb/>naire; </s> <s xml:id="echoid-s11048" xml:space="preserve">mais, les Chapiteaux ſont preſque toûjours quarrés, je veux <lb/>dire auſſi hauts que le Pilaſtre eſt large. </s> <s xml:id="echoid-s11049" xml:space="preserve">L’on prend ün 7<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11050" xml:space="preserve">de cette <lb/>hauteur pour l’Abaque, & </s> <s xml:id="echoid-s11051" xml:space="preserve">le reſte eſt occupé par un Vaſe renverſé <lb/>d’un ſeul rang de Feüillage pareil à ceux du Chapiteau Corinthien. <lb/></s> <s xml:id="echoid-s11052" xml:space="preserve">A l’égard de l’Entablement, il doit être proportionné à la hauteur <lb/>de ces ſortes de Pilaſtres; </s> <s xml:id="echoid-s11053" xml:space="preserve">mais, le plus ſouvent il n’eſt compoſé que <lb/>d’une Corniche ſans Friſe ni Architrave.</s> <s xml:id="echoid-s11054" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11055" xml:space="preserve">Il y en a qui mettent un Attique entre-deux étages à l’exemple <lb/>de Vitruve, qui, dans la Deſcription de ſa Baſilique, ſemble placer <lb/>une maniere d’Attique entre deux Ordonnances de Colomnes. <lb/></s> <s xml:id="echoid-s11056" xml:space="preserve">Mais à vrai dire un Attique, qui ſe trouve ailleurs qu’au haut d’une <lb/>Façade, me paroît faire un méchant effet.</s> <s xml:id="echoid-s11057" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11058" xml:space="preserve">L’aſſemblage des Ordres a fait naître une Queſtion qui a fait beau-<lb/>coup de bruit il y a 40 à 50 ans; </s> <s xml:id="echoid-s11059" xml:space="preserve">ſçavoir dans quel goût on pour-<lb/>roit faire une Ordonnance qui pût être élevée au-deſſus de l’Ordre <lb/>Compoſite; </s> <s xml:id="echoid-s11060" xml:space="preserve">c’eſt-à-dire, inventer un 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11061" xml:space="preserve">Ordre, qui eût au-deſſus du <lb/>5<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11062" xml:space="preserve">les mêmes avantages en délicateſſe & </s> <s xml:id="echoid-s11063" xml:space="preserve">en grace, que le Compo-<lb/>ſite peut avoir ſur les quatre autres. </s> <s xml:id="echoid-s11064" xml:space="preserve">Cet Ordre, qu’on devoit nom-<lb/>mer l’Ordre François, fut propoſé de la part du Roy à tous les ſa-<lb/>vans Architectes de l’Europe, avec un Prix conſiderable pour ceux <lb/>qui produiroient quelque nouveau deſſein qui mériteroit de porter un <lb/>Nom ſiglorieux. </s> <s xml:id="echoid-s11065" xml:space="preserve">Auſſi-tôt les habiles Gens de toute nation & </s> <s xml:id="echoid-s11066" xml:space="preserve">de tout <lb/>pays firent tous leurs efforts pour donner des productions de leurs <lb/>genies; </s> <s xml:id="echoid-s11067" xml:space="preserve">mais, par une fatalité qui ne paroit preſque pas croyable, il <lb/>eſt arrivé que d’un million de differens deſſeins qui ont été propoſés <lb/>il ne s’en eſt pas trouvé un ſeul qui ait merité le moindre applau-<lb/>diſſement. </s> <s xml:id="echoid-s11068" xml:space="preserve">Mr. </s> <s xml:id="echoid-s11069" xml:space="preserve">Blondel dit que la plûpart n’étoient remplis que d’ex-<lb/>travagances, de chimeres gothiques, & </s> <s xml:id="echoid-s11070" xml:space="preserve">de fades alluſions. </s> <s xml:id="echoid-s11071" xml:space="preserve">J’ai vû <pb o="67" file="0533" n="583" rhead="LIVRE V. DE LA DE’CORATION."/> auſſi pluſieurs morceaux, qui n’avoient rien de recommandable, <lb/>quoique fort vantés par des gens d’un certain rang, quiavoient ap-<lb/>paremment intereſt de les faire valoir. </s> <s xml:id="echoid-s11072" xml:space="preserve">Je conviendrai pourtant, <lb/>qu’il y a quelques Profils de l’invention de Sebaſtien le Clerc, qui ne <lb/>doivent point être confondus avec ceux dont je parle: </s> <s xml:id="echoid-s11073" xml:space="preserve">le goût <lb/>exquis de cet Auteur s’eſt aſſés fait admirer des gens les plus dlicats, <lb/>pour avoir un ſentiment avantageux de ce qui vient de luy.</s> <s xml:id="echoid-s11074" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11075" xml:space="preserve">Quoique les peines, que l’on a priſes pour inventer un nouvel <lb/>Ordre, n’ayent pas fait beaucoup d’honneur au dernier ſiécle, on <lb/>auroit pourtant tort d’en demeurer-là: </s> <s xml:id="echoid-s11076" xml:space="preserve">il ſe rencontre quelquefois <lb/>des genies heureux, qui produiſent ſans effort ce que leurs pré deceſ-<lb/>ſeurs ont cherché en vain; </s> <s xml:id="echoid-s11077" xml:space="preserve">car ce que la nature refuſe dans un tems, <lb/>elle le donne quelquefois avec uſure dans un autre. </s> <s xml:id="echoid-s11078" xml:space="preserve">Nous admirons <lb/>aujourd’hui les anciens Architectes: </s> <s xml:id="echoid-s11079" xml:space="preserve">il en viendra peut-être par la <lb/>ſuite pour leſquels on aura les mêmes ſentimens; </s> <s xml:id="echoid-s11080" xml:space="preserve">mais, en attendant, <lb/>l’on peut, ſur un Ordre Compoſé, placer un Ordre Compoſé, à <lb/>l’exemple des Anciens, qui n’ont pas fait difficulté de mettre un <lb/>Corinthien ſur un autre: </s> <s xml:id="echoid-s11081" xml:space="preserve">il ne ſeroit pas non plus mal-à-propos d’y <lb/>mettre des Caritatides ou des Perſiques, parce que ne faiſant point <lb/>d’Ordre particulier, il ſemble qu’ils peuvent convenir l’un & </s> <s xml:id="echoid-s11082" xml:space="preserve">l’au-<lb/>tre à tous les Ordres. </s> <s xml:id="echoid-s11083" xml:space="preserve">Il ne faut pas avoir la délicateſſe de ceux qui <lb/>ne veulent rien ſouffrir dans l’Architecture dont on n’ait des exem-<lb/>ples antiques: </s> <s xml:id="echoid-s11084" xml:space="preserve">car, au ſujet de l’Ordre Compoſé, nous avons autant <lb/>de droit de changer les penſées des Romains, que ceux-ci en ont eu <lb/>d’alterer celles des Grecs; </s> <s xml:id="echoid-s11085" xml:space="preserve">mais, on ne le doit faire qu’avec beaucoup <lb/>de ſageſſe, ſans ſortir de certaines régles generales dans leſquelles on <lb/>remarque que ces mêmes Romains ont toûjours renfermé leur in-<lb/>vention; </s> <s xml:id="echoid-s11086" xml:space="preserve">car, la plûpart des choſes qu’ils ont changé ou ajoûté ne <lb/>ſont point eſſentielles à la beauté de l’Architecture, s’étant toûjours <lb/>conformés aux régles légitimes.</s> <s xml:id="echoid-s11087" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11088" xml:space="preserve">Quelques Architectes de nos jours ont été bien plus hardis, ayant <lb/>entierement abandonné les anciennes régles, pour ne ſuivre que <lb/>celles d’une folle imagination; </s> <s xml:id="echoid-s11089" xml:space="preserve">&</s> <s xml:id="echoid-s11090" xml:space="preserve">, s’ils avoient eû beaucoup d’imi-<lb/>tateurs, l’Architecture Gothique, malgré ſon ridicule, auroit peut-<lb/>être regné une ſeconde fois. </s> <s xml:id="echoid-s11091" xml:space="preserve">L’Egliſe des Théatins à Paris nous en <lb/>offre un exemple qu’on ne devoit pas attendre d’un ſiécle auſſi éclairé <lb/>que le nôtre: </s> <s xml:id="echoid-s11092" xml:space="preserve">car, il ſemble que celui qui l’a bâti ait voulu épuiſer <lb/>tout ce que l’eſprit humain peut inſpirer de plus extravagant; </s> <s xml:id="echoid-s11093" xml:space="preserve">non-<lb/>ſeulement dans l’Ordonnance, dont le goût eſt mille fois plus bizarre <lb/>que ce que l’on n’a jamais vû dans le Gothique, mais même <lb/>dans la diſtribution du terrain, qui pêche contre le ſens-commun.</s> <s xml:id="echoid-s11094" xml:space="preserve"> <pb o="68" file="0534" n="584" rhead="LA SCIENCE DES INGENIEURS,"/> Qu’on me permette encore cette Réflexion. </s> <s xml:id="echoid-s11095" xml:space="preserve">Rien n’eſt plus dan-<lb/>gereux dans la ſocieté, que ceux qui ne veulent pas ſe conformer <lb/>aux maximes generalement reçûës: </s> <s xml:id="echoid-s11096" xml:space="preserve">car, comme le mépris qu’ils en <lb/>font procede toûjours de ce qu’ils n’ont pas aſſés de capacité pour <lb/>en connoître les avantages, ils cherchent à en établir ſuivant leur <lb/>caprice; </s> <s xml:id="echoid-s11097" xml:space="preserve">&</s> <s xml:id="echoid-s11098" xml:space="preserve">, quoi qu’ils donnent dans le faux, l’eſprit de nouveauté <lb/>fait que bien des gens ſe rengent de leur parti. </s> <s xml:id="echoid-s11099" xml:space="preserve">Enſuite, il ne faut <lb/>plus que du tems, pour que les choſes les plus monſtrueuſes ſoient <lb/>regardées comme des Loys ſacrées: </s> <s xml:id="echoid-s11100" xml:space="preserve">la raiſon veut en vain y trou-<lb/>ver à redire; </s> <s xml:id="echoid-s11101" xml:space="preserve">on lui impoſe ſilence, & </s> <s xml:id="echoid-s11102" xml:space="preserve">ce n’eſt qu’en tremblant <lb/>qu’on ôſe ſe déclarer pour elle.</s> <s xml:id="echoid-s11103" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div475" type="section" level="1" n="128"> <head xml:id="echoid-head342" xml:space="preserve">CHAPITRE DOUZIE’ME. <lb/>De la Diſtribution & de la Décoration des Ediſices en général.</head> <p> <s xml:id="echoid-s11104" xml:space="preserve">J’ENTEND par la diſtribution l’uſage qu’on doit faire d’un ter-<lb/>rein dans lequel on peut élever un Bâtiment: </s> <s xml:id="echoid-s11105" xml:space="preserve">cette partie de l’Ar-<lb/>chitecture peut être regardée comme la principale & </s> <s xml:id="echoid-s11106" xml:space="preserve">la plus eſ-<lb/>ſentielle, toutes les autres lui étant ſubordonnées; </s> <s xml:id="echoid-s11107" xml:space="preserve">en effet, quand on <lb/>mettroit Colomnes ſur Colomnes, que les Profils ſeroient plus ré-<lb/>guliers & </s> <s xml:id="echoid-s11108" xml:space="preserve">plus délicats que ceux des plus beaux Edifices antiques, <lb/>& </s> <s xml:id="echoid-s11109" xml:space="preserve">qu’on employeroit les plus habiles Sculpteurs à la Décoration, <lb/>quel ſuccès pourroit-on en attendre, ſi le terrain eſt mal diſtribué, <lb/>que les principales parties n’ayent pas la grandeur, la nobleſſe, & </s> <s xml:id="echoid-s11110" xml:space="preserve"><lb/>les dégagemens qui leur conviennent, ou ſi l’on manquoit dans <lb/>quelque point eſſentiel qui répugnât à la qualité du Bâtiment dont <lb/>il s’agit?</s> <s xml:id="echoid-s11111" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11112" xml:space="preserve">Il eſt vrai que cette partie a bien plus d’étenduë aujourd’huy <lb/>qu’elle n’avoit autrefois. </s> <s xml:id="echoid-s11113" xml:space="preserve">Les François ont pouſſé la diſtribution à un <lb/>point qui les met en cela fort au-deſſus des autres Nations: </s> <s xml:id="echoid-s11114" xml:space="preserve">nous <lb/>avons en France, & </s> <s xml:id="echoid-s11115" xml:space="preserve">en Italie, des Palais faits dans les ſiécles préce-<lb/>dens, dont l’exterieur eſt décoré d’une aſſés belle Architecture, <lb/>tandis que la diſtribution des dedans n’a rien qui y réponde; </s> <s xml:id="echoid-s11116" xml:space="preserve">on <lb/>n’y trouve aucune commodité, il ſemble qu’on ait affecté d’en éloi-<lb/>gner le grand jour & </s> <s xml:id="echoid-s11117" xml:space="preserve">d’y faire regner un crepuſcule perpetuel, <lb/>les Cheminées occupent le plus grand eſpace des Apartemens, les <lb/>Portes ſont petites & </s> <s xml:id="echoid-s11118" xml:space="preserve">donnent une foible idée des lieux où elles <lb/>conduiſent: </s> <s xml:id="echoid-s11119" xml:space="preserve">mais, quoique depuis un ſiécle on ait inventé un nou- <pb o="69" file="0535" n="585" rhead="LIVRE V. DE LA DE’CORATION."/> vel art de la diſtribution, il ne faut pas croire que tout ce qu’on <lb/>bâtit aujourd’hui ſoit exempt de deffauts; </s> <s xml:id="echoid-s11120" xml:space="preserve">par exemple, on fait dans <lb/>des Palais de conſéquence des Veſtibules, des Eſcaliers, des Salons, <lb/>des Anti-Chambres, des Chambres de Parade, des Cabinets, & </s> <s xml:id="echoid-s11121" xml:space="preserve">plu-<lb/>ſieurs autres Piéces de cette nature, d’une grandeur au-deſſus de <lb/>l’ordinaire, & </s> <s xml:id="echoid-s11122" xml:space="preserve">proportionnée à celle de l’Edifice: </s> <s xml:id="echoid-s11123" xml:space="preserve">cela eſt en place, <lb/>& </s> <s xml:id="echoid-s11124" xml:space="preserve">il eſt permis de ſortir des proportions communes dans ces occa-<lb/>ſions; </s> <s xml:id="echoid-s11125" xml:space="preserve">mais il eſt ridicule, comme cela eſt arrivé à pluſieurs Archi-<lb/>tectes, de faire de ſemblables piéces dans une place d’une médiocre <lb/>étenduë, au lieu d’avoir menagé le terrein pour un meilleur uſage.</s> <s xml:id="echoid-s11126" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11127" xml:space="preserve">Il ne ſuffit pas d’employer aſſés bien l’eſpace que l’on veut oc-<lb/>cuper, & </s> <s xml:id="echoid-s11128" xml:space="preserve">de trouver à peu-près toutes les commodités néceſſaires, <lb/>il faut encore en faiſant la diſtribution avoir égard à la décoration <lb/>des dehors, ſoit par des avants-Corps ou Pavillons proportionnés <lb/>à la maſſe de l’Edifice, ſoit en plaçant les Portes & </s> <s xml:id="echoid-s11129" xml:space="preserve">Croiſées, de <lb/>maniere qu’elles faſſent une parfaite ſimetrie, ou en diſtribuant les <lb/>Tremeaux enſorte qu’ils ſoient ſuſceptibles des ornemens qu’on <lb/>voudra y mettre; </s> <s xml:id="echoid-s11130" xml:space="preserve">en un mot, s’il n’y a un accord de toute part, il ne <lb/>faut pas croire qu’on ait l’approbation des perſonnes de bon goût. <lb/></s> <s xml:id="echoid-s11131" xml:space="preserve">On peut dire au contraire, qu’en mariant les dehors avec les com-<lb/>poſitions des dedans, on fait naître un plaiſir ſecret dans l’ame des <lb/>Spectateurs, qui, ſans pouvoir rendre raiſon de la ſatisfaction qu’ils <lb/>reſſentent, ne ſavent à quoi l’attribuer quoiqu’ils ne voyent dans ce <lb/>qu’ils admirent que des Croiſées, des Pilaſtres, des Maſques, des <lb/>Conſoles, & </s> <s xml:id="echoid-s11132" xml:space="preserve">d’autres pareils ornemens qu’ils ont remarqué cent fois <lb/>ailleurs ſans ſentir la même émotion.</s> <s xml:id="echoid-s11133" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11134" xml:space="preserve">Je ne ſaurois m’empêcher de dire, qu’il eſt très-difficile pour ne <lb/>pas dire impoſſible, d’atteindre à un rapport parfait des parties inte-<lb/>rieures d’un Bâtiment avec celles des dehors, lorſqu’un Architecte <lb/>n’eſt pas maître abſolu de ſon ſujet, & </s> <s xml:id="echoid-s11135" xml:space="preserve">qu’on dérange ſes idées le <lb/>plus ſouvent pour des bagatelles; </s> <s xml:id="echoid-s11136" xml:space="preserve">car s’il mollit, & </s> <s xml:id="echoid-s11137" xml:space="preserve">qu’il ait affaire à <lb/>des perſonnes entêtées & </s> <s xml:id="echoid-s11138" xml:space="preserve">prévenuës d’une prétenduë capacité, il <lb/>ne peut qu’être blâmé dans la ſuite, puiſqu’on le rendra reſponſable <lb/>des fautes qu’on lui aura fait faire: </s> <s xml:id="echoid-s11139" xml:space="preserve">les demi-ſavans ſont dangereux <lb/>dans toute ſorte de genre; </s> <s xml:id="echoid-s11140" xml:space="preserve">mais, ils ſont inſuportables en fait de <lb/>Bâtimens, & </s> <s xml:id="echoid-s11141" xml:space="preserve">le fâcheux eſt que tout le monde veut être Architecte.</s> <s xml:id="echoid-s11142" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11143" xml:space="preserve">Comme ce n’eſt point ici le lieu d’enſeigner à faire une diſtribu-<lb/>tion, & </s> <s xml:id="echoid-s11144" xml:space="preserve">qu’on ne le pourroit même qu’en donnant les Plans des plus <lb/>beaux Hôtels de Paris avec les Remarques neceſſaires, je me con-<lb/>tenterai de dire, qu’on ne ſauroit parvenir à faire un Plan achevé, ſi <lb/>en compoſant celui du rez-de-Chauſſée on n’a égard aux ſuperieurs, <pb o="70" file="0536" n="586" rhead="LA SCIENCE DES INGENIEURS,"/> à commencer depuis les ſoûterrains juſqu’au comble: </s> <s xml:id="echoid-s11145" xml:space="preserve">ſans ces pré-<lb/>cautions, on s’expoſe à des inconveniens très-facheux, & </s> <s xml:id="echoid-s11146" xml:space="preserve">qui devien-<lb/>nent quelquefois irréparables; </s> <s xml:id="echoid-s11147" xml:space="preserve">car ce qui rend une diſtribution par-<lb/>faite, c’eſt l’arrangement naturel de toutes les piéces de l’Edifice, <lb/>dans leſquelles il faut conſerver la nobleſſe, la grandeur, & </s> <s xml:id="echoid-s11148" xml:space="preserve">la pro-<lb/>portion qui leur eſt convenable.</s> <s xml:id="echoid-s11149" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11150" xml:space="preserve">Si nous avons ſurpaſſé les Anciens dans la diſtribution, parce qu’ils <lb/>pouvoient avoir moins de délicateſſe, ou que nous jugeons mal de <lb/>leur magnificence, on peur dire avec juſtice que nous ne ſommes <lb/>que leurs copiſtes pour la décoration, & </s> <s xml:id="echoid-s11151" xml:space="preserve">que la plus belle Architec-<lb/>ture de nosjours n’a de prix qu’autant qu’elle eſt conforme à la leur; <lb/></s> <s xml:id="echoid-s11152" xml:space="preserve">mais il eſt plus difficile qu’on ne penſe de la bien imiter, puiſque <lb/>quelque habile que l’on ſoit on ne peut jamais s’aſſurer du ſuccès, ne <lb/>travaillant pour ainſi dire que par conjecture, n’ayant point de princi-<lb/>pes démontrés ſur leſquels on puiſſe ſe déterminer. </s> <s xml:id="echoid-s11153" xml:space="preserve">Si l’on peut ſe <lb/>fonder ſur quelques régles certaines, ce ne peut être que ſur celle de <lb/>la Perſpective qui pourra faire connoîtreles vraies proportions qu’on <lb/>doit ſuivre. </s> <s xml:id="echoid-s11154" xml:space="preserve">On doit donc s’apliquer avec tout le ſoin poſſible <lb/>à l’étude d’une ſcience ſi neceſſaire, & </s> <s xml:id="echoid-s11155" xml:space="preserve">dont l’union eſt ſi étroite <lb/>avec l’Architecture, qu’il eſt preſque impoſſible d’atteindre à la <lb/>perfection de celle-ci ſans avoir une connoiſſance très diſtincte <lb/>de l’autre; </s> <s xml:id="echoid-s11156" xml:space="preserve">car il ſe trouve dans la décoration des grands Edifices <lb/>tant de parties differentes, dont les unes ſont plus enfoncées que les <lb/>autres, qu’il faut convenir qu’on ne ſauroit guére juger de leurs <lb/>effets par une ſimple Elevation Géometralle.</s> <s xml:id="echoid-s11157" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11158" xml:space="preserve">Les ſaillies les plus utiles & </s> <s xml:id="echoid-s11159" xml:space="preserve">les plus belles pour décorer les Bâ-<lb/>timens ſont les Corniches, parce qu’elles les couronnent avec grace <lb/>& </s> <s xml:id="echoid-s11160" xml:space="preserve">conſervent le parement contre les injures de l’air: </s> <s xml:id="echoid-s11161" xml:space="preserve">la hauteur & </s> <s xml:id="echoid-s11162" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0536-01a" xlink:href="note-0536-01"/> la ſaillie des Entablemens dépendent de l’élevation des Edifices & </s> <s xml:id="echoid-s11163" xml:space="preserve"><lb/>de la diſtance d’où ils doivent être vûs: </s> <s xml:id="echoid-s11164" xml:space="preserve">les moindres Corniches ſont <lb/>en Chanfrain, & </s> <s xml:id="echoid-s11165" xml:space="preserve">n’ont qu’une moulure couronnée comme un gros <lb/>Talon, un quart de rond, ou une Doucine avec quelques Filets ou <lb/>Aſtragales, ellesne s’employent qu’aux Bâtimens ruſtiques qu’on ne <lb/>veut point décorer; </s> <s xml:id="echoid-s11166" xml:space="preserve">mais quand on veut les faire plus riches, on <lb/>peut employer à propos celles de l’Entablement d’un des cinq Ordres, <lb/>ſelon qu’on juge qu’elles pourront convenir à l’Edifice: </s> <s xml:id="echoid-s11167" xml:space="preserve">ce qui neſe <lb/>fait guére que lorſqu’on employe tout l’Entablement du même Or-<lb/>dre, puiſqu’à le bien prendre il vaut mieux compoſerla Corniche ex-<lb/>près, afin d’avoir égard aux circonſtances les plus eſſentielles, ſoit <lb/>par raport aux differens effets que peuvent cauſer les moulures, <lb/>ou à la nature de la pierre, qui ne ſe rencontre pas toûjours pro- <pb o="71" file="0537" n="587" rhead="LIVRE V. DE LA DE’CORATION."/> pre pour exprimer des parties délicates: </s> <s xml:id="echoid-s11168" xml:space="preserve">la couleur même peut faire <lb/>beaucoup; </s> <s xml:id="echoid-s11169" xml:space="preserve">car ſi c’eſt une pierre colorée ou mélée, il faut des mou-<lb/>lures qui ayent beaucoup de relief, & </s> <s xml:id="echoid-s11170" xml:space="preserve">qu’on puiſſe diſtinguer aiſé-<lb/>ment, ſans quoi elles cauſent plus de confuſion que d’ornemens; <lb/></s> <s xml:id="echoid-s11171" xml:space="preserve">au lieu que ſi la pierre eſt blanche, il y a moins de ſujetion, à cauſe <lb/>que la lumiere qui s’y réflêchit fait que rien neſe perd dans l’ombre.</s> <s xml:id="echoid-s11172" xml:space="preserve"/> </p> <div xml:id="echoid-div475" type="float" level="2" n="1"> <note position="left" xlink:label="note-0536-01" xlink:href="note-0536-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>48.</note> </div> <p> <s xml:id="echoid-s11173" xml:space="preserve">Pour qu’une Corniche ſoit bien profilée, il faut que les moulures <lb/>ayent entr’elles un certain raport, pour cela on évite que deux ou <lb/>trois moulures ſemblables ſe rencontrent de ſuite, ainſi que plu-<lb/>ſieurs d’une même hauteur; </s> <s xml:id="echoid-s11174" xml:space="preserve">car il doit ſe trouver un contraſte dans <lb/>leur diſtribution par l’opoſé qui regne entr’elles en les faifant alter-<lb/>nativement circulaires & </s> <s xml:id="echoid-s11175" xml:space="preserve">angulaires, ou par la difference de leur <lb/>grandeur: </s> <s xml:id="echoid-s11176" xml:space="preserve">mais, en général, la ſaillie d’une Corniche doit être à <lb/>peu-près égale à ſa hauteur.</s> <s xml:id="echoid-s11177" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11178" xml:space="preserve">Quand le Batiment eſt fort exhauſſé, & </s> <s xml:id="echoid-s11179" xml:space="preserve">que ſon uſage le diſtingue <lb/>des autres, un Entablement entier lui convient beaucoup mieux <lb/>qu’une Corniche ſeule, & </s> <s xml:id="echoid-s11180" xml:space="preserve">la maſſe en eſt couronnée avec beaucoup <lb/>de grace; </s> <s xml:id="echoid-s11181" xml:space="preserve">la proportion doit s’en déterminer en le faiſant comme <lb/>s’il y avoit un Ordre entier; </s> <s xml:id="echoid-s11182" xml:space="preserve">cependant, quand on le juge à propos, <lb/>on peut en diminuer l’Architrave & </s> <s xml:id="echoid-s11183" xml:space="preserve">la Friſe, ce qui doit ſe faire <lb/>avec beaucoup d’Art: </s> <s xml:id="echoid-s11184" xml:space="preserve">ſi l’Entablement eſt tout entier, on doit enri-<lb/>chir la Friſe de Conſoles, & </s> <s xml:id="echoid-s11185" xml:space="preserve">la Corniche de Modillons; </s> <s xml:id="echoid-s11186" xml:space="preserve">on peut <lb/>voir quelques exemples de tout ceci, en conſidérant les Corniches <lb/>& </s> <s xml:id="echoid-s11187" xml:space="preserve">Entablemens qui ſont raportés ſur la Planche 48<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11188" xml:space="preserve">deſquels on <lb/> <anchor type="note" xlink:label="note-0537-01a" xlink:href="note-0537-01"/> pourra tirer des idées pour s’en ſervir dans l’occaſion.</s> <s xml:id="echoid-s11189" xml:space="preserve"/> </p> <div xml:id="echoid-div476" type="float" level="2" n="2"> <note position="right" xlink:label="note-0537-01" xlink:href="note-0537-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>48.</note> </div> <p> <s xml:id="echoid-s11190" xml:space="preserve">Il eſt bon d’ajoûter, qu’on ne doit jamais interrompre le cours d’une <lb/>Corniche, en la coupant à l’endroit des Lucarnes des Etages en ga-<lb/>letas, parce que cela choque le coup d’oeil & </s> <s xml:id="echoid-s11191" xml:space="preserve">eſt contre toutes les <lb/>régles; </s> <s xml:id="echoid-s11192" xml:space="preserve">je dirai auſſi, que quand on veut déterminer la proportion <lb/>des moulures, on peut, au lieu de ſe ſervir des parties du module, <lb/>commencer par tracer la plus grande moulure, enſorte qu’elle ait <lb/>avec toute la hauteur le raport qui conviendra le mieux, enſuite <lb/>diviſer la hauteur de cette moulure en autant de parties égales <lb/>qu’on jugera à propos, & </s> <s xml:id="echoid-s11193" xml:space="preserve">s’en ſervir pour régler les autres parties.</s> <s xml:id="echoid-s11194" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11195" xml:space="preserve">Quant aux ornemens des Fenêtres, les unes ſont compoſées d’un <lb/>Chambranle ſimple ſans aucune moulure, les autres ont un Cham-<lb/>branle avec des moulures & </s> <s xml:id="echoid-s11196" xml:space="preserve">une Corniche au-deſſus: </s> <s xml:id="echoid-s11197" xml:space="preserve">enfin les plus <lb/>belles ſont celles qui ont un Chambranle avec des Conſoles & </s> <s xml:id="echoid-s11198" xml:space="preserve">un <lb/>Fronton ſans montant aux côtés des Chambranles.</s> <s xml:id="echoid-s11199" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11200" xml:space="preserve">Les grandes Croiſées doivent avoir une Corniche aſſés ſaillante <lb/>pour donner du couvert à ceux qui s’y préſentent, & </s> <s xml:id="echoid-s11201" xml:space="preserve">alors on fait <pb o="72" file="0538" n="588" rhead="LA SCIENCE DES INGENIEURS,"/> porter cette ſaillie par deux Conſoles auſſi-bien que l’appui ou ac-<lb/>coudoir qui termine la Croiſée par en bas.</s> <s xml:id="echoid-s11202" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11203" xml:space="preserve">Les Conſoles de la Corniche doivent être auſſi larges en bas qu’en <lb/>haut, afin qu’elles ſuivent régulierement le Chambranle & </s> <s xml:id="echoid-s11204" xml:space="preserve">le mon-<lb/>tant; </s> <s xml:id="echoid-s11205" xml:space="preserve">la largeur du Chambranle peut être d’une 6<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11206" xml:space="preserve">partie de la Croi-<lb/>ſée ou Fenêtre. </s> <s xml:id="echoid-s11207" xml:space="preserve">Au-delà du Chambranle, il y a une platte-Bande <lb/>qui lui ſert d’arriere-corps, elle peut avoir autant de largeur que <lb/>le Chambranle, ou un peu moins, elle ſert particulierement à placer <lb/>les Conſoles de la Corniche, ſi la Corniche n’eſt pas portée par <lb/>des Conſoles. </s> <s xml:id="echoid-s11208" xml:space="preserve">Cet arriere-corps doit être moins large de moitié & </s> <s xml:id="echoid-s11209" xml:space="preserve"><lb/>ſans aucune moulure que celles qui compoſent ſa Corniche. </s> <s xml:id="echoid-s11210" xml:space="preserve">Les <lb/>Conſoles qui portent l’appui doivent être placées au-deſſous du <lb/>Chambranle & </s> <s xml:id="echoid-s11211" xml:space="preserve">avoir même largeur, leurs enroulemens auront bon-<lb/>ne grace s’ils ſe portent de dehors par les côtés. </s> <s xml:id="echoid-s11212" xml:space="preserve">La hauteur de ces <lb/>Conſoles peut être de la moitié de l’ouverture de la Fenêtre tout <lb/>au plus, ou du tiers au moins; </s> <s xml:id="echoid-s11213" xml:space="preserve">on les fait ordinairement plus étroi-<lb/>tes en bas qu’en haut, cependant j’aimerois mieux qu’elles fuſſent <lb/>également larges. </s> <s xml:id="echoid-s11214" xml:space="preserve">Souvent la hauteur du Perron termine le bas de <lb/>ces Conſoles.</s> <s xml:id="echoid-s11215" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11216" xml:space="preserve">La principale Porte d’un Edifice étant la partie la plus remarqua-<lb/>ble de la Façade, il faut neceſſairement qu’elle ſoit décorée à pro-<lb/>portion de la conſéquence du Batiment, ſa grandeur doit même être <lb/>aſſujettie à cette circonſtance, par exemple ſi la Façade retient quel-<lb/>que partie d’un Ordre d’Architecture, il faut pour le Toſcan & </s> <s xml:id="echoid-s11217" xml:space="preserve"><lb/>Dorique que la Porte ait de hauteur un peu moins du double de ſa <lb/>largeur, pour l’Ionique on pourra lui donner poſitivement le dou-<lb/>ble de la largeur, & </s> <s xml:id="echoid-s11218" xml:space="preserve">pour le Corinthien & </s> <s xml:id="echoid-s11219" xml:space="preserve">le Compoſite un peu <lb/>plus; </s> <s xml:id="echoid-s11220" xml:space="preserve">quant à leur Figure, les plus belles ſont rondes ou quarrées; <lb/></s> <s xml:id="echoid-s11221" xml:space="preserve">c’eſt-à-dire qu’elles ſont terminées par un demi-Cercle, ou par une <lb/>platte-Bande, il y en a d’autres qui approchent de ces figures, com-<lb/>me celles dont le ceintre eſt en ance de panier ou ſurbaiſſé, ou qui <lb/>ayant la Figure d’une platte-Bande ſont un peu ceintrées. </s> <s xml:id="echoid-s11222" xml:space="preserve">Quand <lb/>on les fait comme cette derniere, le trait le plus parfait eſt celui <lb/>qui ſe décrit ſur la Baſe d’un Triangle équilateral dont le ſommet <lb/>eſt le centre; </s> <s xml:id="echoid-s11223" xml:space="preserve">je ne dis rien de celles qu’on fait à pan; </s> <s xml:id="echoid-s11224" xml:space="preserve">c’eſt-à-dire <lb/>terminées par pluſieurs faces, parce qu’elles ont mauvaiſe grace, <lb/>& </s> <s xml:id="echoid-s11225" xml:space="preserve">ne ſont point aprouvées.</s> <s xml:id="echoid-s11226" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11227" xml:space="preserve">Si l’on veut avoir un Balcon au-deſſus de la Porte, on peut le faire <lb/>porter par des Colomnes quand le lieu le permet; </s> <s xml:id="echoid-s11228" xml:space="preserve">en ce cas on fait <lb/>ſaillir les ornemens d’Architecture: </s> <s xml:id="echoid-s11229" xml:space="preserve">ou bien, ſi l’on ne fait pas de <lb/>Colomnes, le Balcon eſt porté par des Conſoles; </s> <s xml:id="echoid-s11230" xml:space="preserve">mais lorſqu’on eſt <pb o="73" file="0539" n="589" rhead="LIVRE V. DE LA DE’CORATION."/> obligé de ménager la Place, on fait des Pilaſtres ou avant-Corps <lb/>qui ont peu de ſaillie, quelquefois même on prend la Porte dans <lb/>un renfoncement, & </s> <s xml:id="echoid-s11231" xml:space="preserve">alors les ornemens ſe diſtribuent ſelon la ne-<lb/>ceſſité & </s> <s xml:id="echoid-s11232" xml:space="preserve">les circonſtances.</s> <s xml:id="echoid-s11233" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11234" xml:space="preserve">A l’égard des Entablemens qui couronnent les Portes, Scamozzy <lb/>veut qu’ils ayent pour l’Ordre Toſcan la 4<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11235" xml:space="preserve">partie de la hauteur du <lb/>vuide, & </s> <s xml:id="echoid-s11236" xml:space="preserve">la 5<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11237" xml:space="preserve">partie pour l’Ordre Compoſé, & </s> <s xml:id="echoid-s11238" xml:space="preserve">qu’on prenne des <lb/>moyennes proportionnelles entre ces deux Ordres pour l’Ionique, <lb/>le Dorique, & </s> <s xml:id="echoid-s11239" xml:space="preserve">le Compoſite; </s> <s xml:id="echoid-s11240" xml:space="preserve">enſuite la hauteur de l’Entablement <lb/>doit être diviſé en 15 parties, dont on en donne 5 à l’Architrave, <lb/>4 à la Friſe, & </s> <s xml:id="echoid-s11241" xml:space="preserve">6 à la Corniche, & </s> <s xml:id="echoid-s11242" xml:space="preserve">les moulures ſe font à proportion: <lb/></s> <s xml:id="echoid-s11243" xml:space="preserve">la largeur des piés-droits ou montans des Chambranles & </s> <s xml:id="echoid-s11244" xml:space="preserve">ſes mou-<lb/>lures doivent être pareilles à celles du Linteau, dont le Profil eſt <lb/>ordinairement ſemblable à celui de l’Architrave.</s> <s xml:id="echoid-s11245" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11246" xml:space="preserve">Il faut autant qu’il eſt poſſible laiſſer les venteaux des grandes <lb/>Portes de toute leur hauteur, à moins qu’on n’en ſoit empêché par <lb/>un entre-ſole. </s> <s xml:id="echoid-s11247" xml:space="preserve">Si la Porte eſt ronde, & </s> <s xml:id="echoid-s11248" xml:space="preserve">qu’on y mette un dormant, <lb/>il doit occuper la partie ceintrée, enſorte que l’impoſte continué <lb/>ſerve de Linteau; </s> <s xml:id="echoid-s11249" xml:space="preserve">à l’égard de leur compartiment il y faut peu de <lb/>panneaux, & </s> <s xml:id="echoid-s11250" xml:space="preserve">que ceux d’enbas ſoient arraſés comme du Parquet, <lb/>que la richeſſe des cadres & </s> <s xml:id="echoid-s11251" xml:space="preserve">des moulures ſoient conformes à la <lb/>Décoration de l’Architecture; </s> <s xml:id="echoid-s11252" xml:space="preserve">ſi l’on y pratique des ornemens de <lb/>Sculpture, il faut qu’ils ayent peu de relief, faiſant enſorte qu’ils <lb/>ſe trouvent dans l’épaiſſeur du bois ſans être adaptés.</s> <s xml:id="echoid-s11253" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11254" xml:space="preserve">Pour dire auſſi quelque choſe de l’interieur des Edifices, il faut <lb/>convenir qu’on n’a jamais eu tant de Goût qu’on en remarque au-<lb/>jourd’hui dans les Appartemens de conſéquence; </s> <s xml:id="echoid-s11255" xml:space="preserve">la maniere d’or-<lb/>ner les Cheminées demanderoit elle ſeule un grand détail, ſi l’on <lb/>vouloit raporter des exemples pour montrer l’Art de mêler à pro-<lb/>pos le Marbre, la Sculpture, & </s> <s xml:id="echoid-s11256" xml:space="preserve">le Bronze doré pour accompagner <lb/>les Glaces qui en font le principal ornement; </s> <s xml:id="echoid-s11257" xml:space="preserve">mais, je renvoye le <lb/>Lecteur au Livre de Daviler, qui a traité ce ſujet à fond, & </s> <s xml:id="echoid-s11258" xml:space="preserve">me <lb/>contenterai de parler des autres ornemens qui ſemblent apartenir <lb/>eſſentiellement à l’Architecture.</s> <s xml:id="echoid-s11259" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11260" xml:space="preserve">Les Anciens, au rapport de Vitruve, ornoient leurs Plafonds de <lb/>bois précieux & </s> <s xml:id="echoid-s11261" xml:space="preserve">d’ouvrages de Marqueterie, fort riches par la di-<lb/>verſité des bois de couleur, de l’Yvoire, & </s> <s xml:id="echoid-s11262" xml:space="preserve">de nacre de Perle, dont <lb/>ils compoſoient des compartimens qui étoient enrichis par des la-<lb/>mes de Bronze. </s> <s xml:id="echoid-s11263" xml:space="preserve">Il eſt conſtant que les Plafonds conviennent fort aux <lb/>Salons & </s> <s xml:id="echoid-s11264" xml:space="preserve">aux grandes piéces où la hauteur des Planchers donnent <lb/>affés d’éloignement pour les voir d’une diſtance raiſonnable, parce <pb o="74" file="0540" n="590" rhead="LA SCIENCE DES INGENIEURS,"/> que dans les petites piéces il faut le moins de relief qu’il ſe peut. <lb/></s> <s xml:id="echoid-s11265" xml:space="preserve">Pour faire la diviſion des compartimens, les cadres doivent répon-<lb/>dre au vuide des murs, comme Fenêtres & </s> <s xml:id="echoid-s11266" xml:space="preserve">Portes, ce que les Poû-<lb/>tres réglent aſſés facilement. </s> <s xml:id="echoid-s11267" xml:space="preserve">Dans les grandes piéces il faut de gran-<lb/>des parties, particulierement une qui marque le milieu & </s> <s xml:id="echoid-s11268" xml:space="preserve">qui ſoit <lb/>differente des autres par ſa figure; </s> <s xml:id="echoid-s11269" xml:space="preserve">par exemple, elle doit être ronde <lb/>ou octogone pour les piéces quarrées, & </s> <s xml:id="echoid-s11270" xml:space="preserve">ovale pour les longues: </s> <s xml:id="echoid-s11271" xml:space="preserve"><lb/>les enfoncemens peuvent être ornés de Roſes tombantes, qui ne doi-<lb/>vent point exceder l’arraſement des Poûtres principales; </s> <s xml:id="echoid-s11272" xml:space="preserve">les Corni-<lb/>ches ou Entablemens doivent être tellement proportionnés, que <lb/>leurs Profils ayent la même hauteur que s’il y avoit un Ordre au-<lb/>deſſous, parce qu’alors on eſt ſur que la Corniche ne ſera ni trop <lb/>puiſſante ni trop foible lorſqu’elle ſera élévée à la hauteur de l’Ordre <lb/>qu’elle doit couronner: </s> <s xml:id="echoid-s11273" xml:space="preserve">à l’égard de la Friſe, elle peut recevoir de <lb/>beaux ornemens, mais il faut qu’ils ſoient répandus avec choix & </s> <s xml:id="echoid-s11274" xml:space="preserve"><lb/>avec goût, & </s> <s xml:id="echoid-s11275" xml:space="preserve">qu’ils conviennent au lieu où ils ſont employés; </s> <s xml:id="echoid-s11276" xml:space="preserve">mais <lb/>pour régler d’une maniere generale la proportion que doivent avoir <lb/>les Entablemens qui portent les Plafonds, s’il n’y a qu’un Architrave <lb/>ou Impoſte, il faut ſelon Scamozzy qu’elle ait la 16<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11277" xml:space="preserve">partie de la <lb/>hauteur depuis le Plancher juſques ſous le Plafond; </s> <s xml:id="echoid-s11278" xml:space="preserve">& </s> <s xml:id="echoid-s11279" xml:space="preserve">ſi le lieu <lb/>permet d’y mettre une Corniche, ſoit avec modillons ou ſans mo-<lb/>dillons, il faut qu’elle ait alors la 13<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11280" xml:space="preserve">partie & </s> <s xml:id="echoid-s11281" xml:space="preserve">demi de cette hauteur. </s> <s xml:id="echoid-s11282" xml:space="preserve"><lb/>Daviler veut qu’on donne aux Corniches la 12<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11283" xml:space="preserve">partie de la hauteur <lb/>de Chambres, ou, ce qui revient au même, un pouce par pied, <lb/>& </s> <s xml:id="echoid-s11284" xml:space="preserve">cela pour les piéces qui auroient depuis 8 pieds juſqu’à 15 d’ex-<lb/>hauſſement, & </s> <s xml:id="echoid-s11285" xml:space="preserve">pour celles qui en ont d’avantage & </s> <s xml:id="echoid-s11286" xml:space="preserve">où l’on a coû-<lb/>tume de faire des Entablemens, il prétend qu’un 10<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11287" xml:space="preserve">de la hau-<lb/>teur conviendroit mieux.</s> <s xml:id="echoid-s11288" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11289" xml:space="preserve">Pour les ornemens des Portes des Appartemens, il faut en divi-<lb/>ſer la hauteur en 15 parties, dont on en donnera 5 à l’Architrave <lb/>ou Linteau, 4 à la Friſe, & </s> <s xml:id="echoid-s11290" xml:space="preserve">6 à la Corniche, le Chambranle ne doit <lb/>jamais avoir plus de 2 faces avec ſes moulures; </s> <s xml:id="echoid-s11291" xml:space="preserve">on peut auſſi met-<lb/>tre des Conſoles avec de la Sculpture pour porter les Corniches <lb/>& </s> <s xml:id="echoid-s11292" xml:space="preserve">ces Conſoles portent ſur de petits montans au côté des Cham-<lb/>branles.</s> <s xml:id="echoid-s11293" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11294" xml:space="preserve">Je ne m’étend pas beaucoup ſur la Décoration interieure des <lb/>Edifices, parce qu’il eſt bien difficile d’y appliquer des régles auſ-<lb/>quelles le caprice veüille ſe ſoûmettre: </s> <s xml:id="echoid-s11295" xml:space="preserve">car, ſur ce ſujet, les Archi-<lb/>tectes ont tous les jours des idées nouvelles; </s> <s xml:id="echoid-s11296" xml:space="preserve">& </s> <s xml:id="echoid-s11297" xml:space="preserve">s’il s’en trouve qui <lb/>ont fait des choſes dignes d’admiration, il faut avoüer qu’il y en a <lb/>auſſi un grand nombre d’autres qui en ont imaginées qui ne ſont <pb o="75" file="0541" n="591" rhead="LIVRE V. DE LA DE’CORATION."/> point ſuportables: </s> <s xml:id="echoid-s11298" xml:space="preserve">&</s> <s xml:id="echoid-s11299" xml:space="preserve">, pour faire voir que je n’en parle qu’après les <lb/>plus habiles gens, voici ce que dit Mr. </s> <s xml:id="echoid-s11300" xml:space="preserve">Courtonne, Architecte du <lb/>Roy, à la fin de ſon Traité de Perſpective.</s> <s xml:id="echoid-s11301" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11302" xml:space="preserve">Pour dire à preſent quelque choſe des parties interieures des <lb/>Palais & </s> <s xml:id="echoid-s11303" xml:space="preserve">des Hôtels les plus conſidérables, on a fait de ſi grands <lb/>changemens à leurs décorations depuis une trentaine d’années, <lb/>qu’on ne s’y reconnoît plus aujourd’hui, & </s> <s xml:id="echoid-s11304" xml:space="preserve">l’on auroit le dernier <lb/>mépris pour un Architecte quin’ajoûteroit pas quelque nouveauté <lb/>ſinguliere à toutes celles qu’on a introduites depuis ce même tems, <lb/>contre l’uſage, & </s> <s xml:id="echoid-s11305" xml:space="preserve">peut-être même contre la raiſon & </s> <s xml:id="echoid-s11306" xml:space="preserve">le bon-ſens. <lb/></s> <s xml:id="echoid-s11307" xml:space="preserve">Je ſçai bien qu’on s’y eſt tellement accoûtumé, qu’il ſeroit dan-<lb/>gereux d’aller contrele torrent, & </s> <s xml:id="echoid-s11308" xml:space="preserve">de ſe roidir contre des modes <lb/>que trente années de preſcription ſemblent avoir aſſés autoriſées: </s> <s xml:id="echoid-s11309" xml:space="preserve"><lb/>auſſi mon intention n’eſt pas de les cenſurer; </s> <s xml:id="echoid-s11310" xml:space="preserve">mais, on me per-<lb/>mettra de dire en paſſant, que l’inconſtance de notre Nation avoit <lb/>aſſés de matiere à s’exercer ſur les choſes de peu de durée, comme <lb/>ſont toutes celles qui ont du mouvement: </s> <s xml:id="echoid-s11311" xml:space="preserve">les Meubles, les Car-<lb/>roſſes, les Habillemens, ſont de cette nature, au nombre deſ-<lb/>quelles on ne doit pas mettre les Edifices, & </s> <s xml:id="echoid-s11312" xml:space="preserve">tout ce qui en fait <lb/>partie, dont la durée doit aller juſqu’à nos derniers neveux.</s> </p> <p> <s xml:id="echoid-s11313" xml:space="preserve">Il eſt vrai que des ornemens de Sculpture bien traités relevent <lb/>infiniment les beautés del’Architecture, & </s> <s xml:id="echoid-s11314" xml:space="preserve">ſur-tout dans les parties <lb/>interieures des Bâtimens dont il s’agit en cet endroit; </s> <s xml:id="echoid-s11315" xml:space="preserve">mais com-<lb/>me ils ne ſont à proprement parler qu’acceſſoires, & </s> <s xml:id="echoid-s11316" xml:space="preserve">qu’on doit <lb/>toûjours regarder la proportion de tousles membres d’Architec-<lb/>ture comme le principal objet, il ne faut s’en ſervir qu’avec beau-<lb/>coup de ménagement, ſi l’on veut que l’œil ſoit fatisfait & </s> <s xml:id="echoid-s11317" xml:space="preserve">qu’il <lb/>en goûte pleinement toutes les beautés: </s> <s xml:id="echoid-s11318" xml:space="preserve">mais, lorſqu’on jette des <lb/>ornemens ſur toutes les parties ſans choix & </s> <s xml:id="echoid-s11319" xml:space="preserve">ſansnéceſſité, il n’y a <lb/>plus que de la confuſion, l’œil ne ſait plus où ſe repoſer, l’Ar-<lb/>chitecture eſt cachée ſous ces voiles, & </s> <s xml:id="echoid-s11320" xml:space="preserve">rien ne nous frape, parce <lb/>que rien ne nous émeut aſſés pour le ſentir.</s> </p> <p> <s xml:id="echoid-s11321" xml:space="preserve">Comme ces Réflexions nous meneroient trop loin, s’il falloit ci-<lb/>ter des exemples qui déplairoient ſans doute auxperſonnes inte-<lb/>reſſées, je me contenterai de dire que ce n’eſt pas encore aſſés de <lb/>retrancher la confuſion des ornemens de Sculpture, ſi l’on n’en ſait <lb/>pas faire le choix qui dépend ordinairement de la qualité des em-<lb/>ploys & </s> <s xml:id="echoid-s11322" xml:space="preserve">même des inclinations particulieres des Seigneurs qui <lb/>font bâtir. </s> <s xml:id="echoid-s11323" xml:space="preserve">On pourra donc choiſir parmi tous les differens Tro-<lb/>phées ou Attributs de Guerre, de Marine, de Chaſſe, de Mu-<lb/>ſique, de Science, & </s> <s xml:id="echoid-s11324" xml:space="preserve">tant d’autres que je pourrois nommer, ceux <pb o="76" file="0542" n="592" rhead="LA SCIENCE DES INGENIEURS,"/> qui conviendront le mieux auſujet que l’on aura à traiter; </s> <s xml:id="echoid-s11325" xml:space="preserve">& </s> <s xml:id="echoid-s11326" xml:space="preserve">c’eſt <lb/>à quoi l’on doit s’étudier le plus, quand on veut avoir l’approba-<lb/>tion des connoiſſeurs.</s> </p> <p> <s xml:id="echoid-s11327" xml:space="preserve">Mais comme ces dedans ſont aujourd’hui d’une très grande <lb/>importance par la grande dépenſe que la mode a rendu comme <lb/>neceſſaire, il faut que l’Architecte épuiſe tous les ſecrets de ſon <lb/>art à la diſtribution & </s> <s xml:id="echoid-s11328" xml:space="preserve">l’arrangement de toutes leurs parties, qui <lb/>conſiſtent dans une belle proportion, dans un choix délicat des <lb/>plus beaux Profils, & </s> <s xml:id="echoid-s11329" xml:space="preserve">dans une grande varieté.</s> </p> <p> <s xml:id="echoid-s11330" xml:space="preserve">J’entens par la proportion la hauteur qu’il faut donner aux <lb/>Corniches ſous les Plafonds, la diſtribution des Pilaſtres, Pan-<lb/>neaux, Cadres, & </s> <s xml:id="echoid-s11331" xml:space="preserve">autres parties des Lambris de Menuiſerie dont <lb/>l’arrangement dépend de la grandeur des piéces, de leur hauteur, <lb/>& </s> <s xml:id="echoid-s11332" xml:space="preserve">des ſujetions cauſées par les Portes, Croiſées, ou Cheminées.</s> </p> <p> <s xml:id="echoid-s11333" xml:space="preserve">Les Profils, qui ſe font dans ces piéces, ſont bien differens de <lb/>ceux que l’on fait au dehors: </s> <s xml:id="echoid-s11334" xml:space="preserve">ils doivent être fort délicats, avoir <lb/>peu de ſaillie, auſſi-bien que les ornemens de Sculpture qui s’y <lb/>font; </s> <s xml:id="echoid-s11335" xml:space="preserve">& </s> <s xml:id="echoid-s11336" xml:space="preserve">l’Architecte doit en faire lui-même les Profils, & </s> <s xml:id="echoid-s11337" xml:space="preserve">ne s’en <lb/>rapporter jamais aux Ouvriers.</s> </p> <p> <s xml:id="echoid-s11338" xml:space="preserve">A l’égard de la varieté, elle doit regner dans toutes lespiéces <lb/>d’un Appartement, c’eſt-à-dire que les deſſeins en doivent être <lb/>differens auſſi-bien que les Profils & </s> <s xml:id="echoid-s11339" xml:space="preserve">les ornemens; </s> <s xml:id="echoid-s11340" xml:space="preserve">avec cette <lb/>remarque, que les premieres piéces ſe font pour l’ordinaire moins <lb/>riches que celles qui ſuivent.</s> </p> <p> <s xml:id="echoid-s11341" xml:space="preserve">Enfin, ſi l’on veut donner toute la perfection à ſon ouvrage, il ne <lb/>faut pas ſe contenter de donner aux Ouvriers un deſſein bien lavé <lb/>& </s> <s xml:id="echoid-s11342" xml:space="preserve">cotté pour chaque piéce, on doit le faire crayonner en grand <lb/>ſur le lieu même où doit être poſé le Lambris, & </s> <s xml:id="echoid-s11343" xml:space="preserve">y faire deſſiner <lb/>le plus exactement que l’on pourra tous les ornemens qu’on vou-<lb/>dray mettre, afin de pouvoir corriger, augementer, ou diminuer <lb/>les parties qui paroîtront trop fortes ou trop foibles; </s> <s xml:id="echoid-s11344" xml:space="preserve">car on juge <lb/>bien autrement de ces ſortes d’ouvrages quand on les voit dans leur <lb/>grandeur naturelle, qu’on ne fait ſur un deſſein réduit en petit, ce <lb/>que l’experience apprendra beaucoup mieux que le diſcours.</s> </p> <p> <s xml:id="echoid-s11345" xml:space="preserve">On peut voir déja par le peu deremarques que nous avons faites <lb/>jufqu’ici, que les connoiſſances néceſſaires à un bon Architecte <lb/>ont plus détenduë qu’on ne s’imagine, & </s> <s xml:id="echoid-s11346" xml:space="preserve">qu’il ne ſuffit pas d’avoir <lb/>exercé la fonction de deſſinateur pendant quelques années pour <lb/>en mériter le titre, comme cela n’eſt que trop ordinaire; </s> <s xml:id="echoid-s11347" xml:space="preserve">car bien <lb/>loin d’avoir acquis la plus grande partie des Sciences qui ſont ab-<lb/>ſolument neceſſaires, on prend cette qualité ſans avoir même la <pb o="77" file="0543" n="593" rhead="LIVRE V. DE LA DE’CORATION."/> pratique, ni cette experience conſommée dans les Bâtimens, & </s> <s xml:id="echoid-s11348" xml:space="preserve"><lb/>qui ne s’apprend point dans le Cabinet, mais par des Travaux <lb/>pénibles & </s> <s xml:id="echoid-s11349" xml:space="preserve">non interrompus. </s> <s xml:id="echoid-s11350" xml:space="preserve">Ilne faut plus donc s’étonner, ſi l’Ar-<lb/>chitecture a perdu beaucoup de ſon premier éclat depuis un cer-<lb/>tain nombre d’années; </s> <s xml:id="echoid-s11351" xml:space="preserve">& </s> <s xml:id="echoid-s11352" xml:space="preserve">l’on doit même apprehender que ce mal <lb/>n’augmente, ſi l’on n’exige point d’autres diſpoſitions de ceux qui <lb/>ſe prévalent de cette qualité.</s> </p> <p> <s xml:id="echoid-s11353" xml:space="preserve">Comme ce Diſcours de Mr Courtonne renferme pluſieurs choſes <lb/>inſtructives, je n’y ai rien voulu changer: </s> <s xml:id="echoid-s11354" xml:space="preserve">j’ai ſuprimé ſeulement un <lb/>article où il m’a parû qu’il marquoit un peu trop d’aigreur contre <lb/>quelques perſonnes de ſa profeſſion, qu’il ne nomme pas à la verité, <lb/>mais dont l’aplication eſt à craindre; </s> <s xml:id="echoid-s11355" xml:space="preserve">au reſte, je reviens à l’expli-<lb/>cation de quelques ſujets qui doivent finir ce Chapitre.</s> <s xml:id="echoid-s11356" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11357" xml:space="preserve">L’on fait toûjours un Peron aux grands Bâtimens, comme à l’en-<lb/>trée d’une Egliſe, d’un Palais, ou de tout autre Edifice conſidéra-<lb/>ble: </s> <s xml:id="echoid-s11358" xml:space="preserve">un Peron, comme l’on ſait, eſt élevé par pluſieurs marches ou <lb/>dégrés, dont le Pallier pour bien faire doit s’étendre ſur toute la <lb/>largeur du Portail, les marches ſelon Vitruve doivent être en nom-<lb/>bre impair de 5 à 6 pouces de hauteur au plus, ſur 10 à 12 pouces <lb/>de giron; </s> <s xml:id="echoid-s11359" xml:space="preserve">c’eſt-à-dire qu’il faut leur donner pour largeur environ le <lb/>double de leur hauteur, afin de rendre la montée plus douce & </s> <s xml:id="echoid-s11360" xml:space="preserve">plus <lb/>facile.</s> <s xml:id="echoid-s11361" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11362" xml:space="preserve">Quand un Peron eſt élevé de 13 à 15 marches, il eſt à propos <lb/>d’en interrompre la ſuite par un ou deux repos, afin de n’avoir pas <lb/>tant de dégrés à monter de ſuite, & </s> <s xml:id="echoid-s11363" xml:space="preserve">que la vûë ne ſe trouve bleſſée <lb/>en deſcendant une ſi grande hauteur ſans appui; </s> <s xml:id="echoid-s11364" xml:space="preserve">mais il faut ſur-tout <lb/>prendre garde que le Peron ſoit toûjours pratiqué dans la hauteur <lb/>du ſocle ou ſoûbaſſement de l’Edifice, obſervant que quoique le <lb/>ſoûbaſſement tienne lieu ici de Piédeſtal continué, il ne doit avoir <lb/>ni Baſe ni Corniche.</s> <s xml:id="echoid-s11365" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11366" xml:space="preserve">Pour faire auſſi mention des Baluſtres & </s> <s xml:id="echoid-s11367" xml:space="preserve">Baluſtrades qui ſe pra-<lb/>tiquent ſi utilement dans les Edifices, ſoit pour la commodité ou <lb/>ſeulement pour la décoration (comme quand on en fait au-deſſus de <lb/>la Corniche des Entablemens pour égaïer une Façade & </s> <s xml:id="echoid-s11368" xml:space="preserve">la terminer <lb/>avec grace) l’on ſaura que les Baluſtrades ne ſont autre choſe qu’une <lb/>ſuite de Baluſtres compoſée d’une ou’de pluſieurs travées terminées <lb/>par des Piédeſtaux de même hauteur, le tout portant une tablette <lb/>en maniere d’appui. </s> <s xml:id="echoid-s11369" xml:space="preserve">Ces travées doivent finir par des demi-Pilaſtres <lb/>joints aux Piédeſtaux: </s> <s xml:id="echoid-s11370" xml:space="preserve">les Baluſtres ſe font de pluſieurs figures; </s> <s xml:id="echoid-s11371" xml:space="preserve">mais <lb/>les ronds, & </s> <s xml:id="echoid-s11372" xml:space="preserve">les quarrés, ſont préférables à tous les autres.</s> <s xml:id="echoid-s11373" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11374" xml:space="preserve">Au lieu de Baluſtres, on fait quelquesfois des entre-lacs, qui n’ont <pb o="78" file="0544" n="594" rhead="LA SCIENCE DES INGENIEURS,"/> pas moins d’agrément: </s> <s xml:id="echoid-s11375" xml:space="preserve">on les rend plus ou moins délicats, ſuivant <lb/>les lieux où ils doivent être placés par exemple, ceux qui ſont éle-<lb/>vés au-deſſus d’un Bâtiment, qu’on ne pourra voir que de loin, doi-<lb/>vent être plus maſſifs que ceux qui ſont faits pour être vûs de près.</s> <s xml:id="echoid-s11376" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11377" xml:space="preserve">Les Trophées compoſent encore dans l’Architecture un orne-<lb/>ment fort noble, leur figure eſt un tronc d’Arbre chargé & </s> <s xml:id="echoid-s11378" xml:space="preserve">envi-<lb/>ronné d’Armes de toute ſorte d’eſpece, leur origne vient des Grecs <lb/>qui dreſſoient ſur le Champ de Bataille un tronc chargé des dépoüil-<lb/>les des Ennemis pour marquer leur Victoire. </s> <s xml:id="echoid-s11379" xml:space="preserve">Ces monumens étoient <lb/>conſacrés à Mars, & </s> <s xml:id="echoid-s11380" xml:space="preserve">l’on n’y pouvoit toucher ſans ſacrilege, ſi on <lb/>en juge par ce que raporte Vitruve dans le huitiéme Chapitre de <lb/>ſon ſecond Livre, où il dit que la Reine Artemiſe, ayant pris la <lb/>Ville de Rhodes, dreſſa un Trophée dans le milieu de la Place avec <lb/>deux Statues de Bronze, dont l’une étoit élevée à ſa gloire, & </s> <s xml:id="echoid-s11381" xml:space="preserve">l’autre <lb/>marquoit la Ville de Rhodes ſous des ſignes de ſervitude; </s> <s xml:id="echoid-s11382" xml:space="preserve">& </s> <s xml:id="echoid-s11383" xml:space="preserve">que <lb/>les Rhodiens dans la ſuite n’ôſant y toucher le renfermerent d’une <lb/>enceinte, parce que, ajoûte-il, il n’étoit pas permis d’ôter les Tro-<lb/>phées conſacrés aux Dieux.</s> <s xml:id="echoid-s11384" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11385" xml:space="preserve">Les Trophées peuvent ſe faire dans toute ſorte de goût, ſelon le <lb/>genre de l’Edifice où on veut les apliquer: </s> <s xml:id="echoid-s11386" xml:space="preserve">par exemple, on en fait <lb/>de Livres, de Spheres, de Globes, & </s> <s xml:id="echoid-s11387" xml:space="preserve">d’Inſtrumens de Mathema-<lb/>tique, pour repréſenter les Arts & </s> <s xml:id="echoid-s11388" xml:space="preserve">les Sciences, d’autres avec des <lb/>Inſtrumens de Muſique, d’autres qui conviennent à l’Agriculture, <lb/>d’autres enfin pour la Marine, les Manufactures, & </s> <s xml:id="echoid-s11389" xml:space="preserve">les Magaſins <lb/>publics ou Arſenaux.</s> <s xml:id="echoid-s11390" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11391" xml:space="preserve">A l’égard des Trophées d’Armes, qui ſont les plus ordinaires & </s> <s xml:id="echoid-s11392" xml:space="preserve"><lb/>les plus conſidérables, il ſemble que lorſqu’il s’agit de quelque Edi-<lb/>fice Militaire, il convient beaucoup mieux de ſe ſervir des Armes <lb/>qui ſont en uſage aujourd’hui, que d’employer celles dont ſe ſer-<lb/>voient les Anciens: </s> <s xml:id="echoid-s11393" xml:space="preserve">nos Canons, nos Mouſquets, nos Mortiers, <lb/>nos Bombes, nos Drapeaux, nos Picques, nos Tambours, nos <lb/>Timbales, nos Trompettes, &</s> <s xml:id="echoid-s11394" xml:space="preserve">c. </s> <s xml:id="echoid-s11395" xml:space="preserve">ne ſont point moins nobles ni <lb/>moins beaux à la vûë, quand ils ſont diſpoſés enſemble avec Art, <lb/>que les Boucliers, les Carquois, les Fléches, les Baliſtes, les Cata-<lb/>pultes, les Belliers, & </s> <s xml:id="echoid-s11396" xml:space="preserve">les autres Armes des Anciens. </s> <s xml:id="echoid-s11397" xml:space="preserve">Au reſte, tout <lb/>ce qui s’appelle ornement doit dépendre du Jugement de l’Archi-<lb/>tecte; </s> <s xml:id="echoid-s11398" xml:space="preserve">c’eſt en cela qu’on connoîtra ſon goût & </s> <s xml:id="echoid-s11399" xml:space="preserve">ſa capacité, non-<lb/>ſeulement dans l’invention des Sujets, mais dans la juſte aplication <lb/>qu’il en ſaura faire.</s> <s xml:id="echoid-s11400" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11401" xml:space="preserve">Lorſque l’on veut décorer une Place publique qui doit contri-<lb/>buer à la beauté d’une Ville, on ne ſauroit donner trop d’aparence <pb o="79" file="0545" n="595" rhead="LIVRE V. DE LA DE’CORATION."/> aux Bâtimens qui l’environnent. </s> <s xml:id="echoid-s11402" xml:space="preserve">Or, pour que la magnificence & </s> <s xml:id="echoid-s11403" xml:space="preserve"><lb/>l’utilité ſe trouvent de concert, il eſt à propos de pratiquer 2 éta-<lb/>ges dans la hauteur de l’Ordonnance; </s> <s xml:id="echoid-s11404" xml:space="preserve">&</s> <s xml:id="echoid-s11405" xml:space="preserve">, ſi on éleve le tout ſur un <lb/>Ordre ruſtique, l’Ordonnance en aura une augmentation de beau-<lb/>té: </s> <s xml:id="echoid-s11406" xml:space="preserve">c’eſt ce que l’on a fait avec beaucoup de ſuccés aux Places de <lb/>Vendôme & </s> <s xml:id="echoid-s11407" xml:space="preserve">de Victoire, à Paris.</s> <s xml:id="echoid-s11408" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11409" xml:space="preserve">On pourra élever une Baluſtrade au-deſſus de l’Entablement, pour <lb/>terminer agréablement la Façade, & </s> <s xml:id="echoid-s11410" xml:space="preserve">cacher en partie le comble qui <lb/>ne fait jamais un bon effet quand il eſt queſtion d’une belle Archi-<lb/>tecture: </s> <s xml:id="echoid-s11411" xml:space="preserve">mais à propos des Baluſtrades, j’ai oublié de dire ci-devant <lb/>que le Socle ſur lequel on poſoit les Baluſtres devoit avoir une hau-<lb/>teur égale à la ſaillie entiere de l’Entablement, & </s> <s xml:id="echoid-s11412" xml:space="preserve">même quelque <lb/>choſe de plus; </s> <s xml:id="echoid-s11413" xml:space="preserve">& </s> <s xml:id="echoid-s11414" xml:space="preserve">qu’il falloit donner aux Baluſtres 2 pieds de hau-<lb/>teur comme on l’a pratiqué aux plus beaux Bâtimens de Paris: <lb/></s> <s xml:id="echoid-s11415" xml:space="preserve">j’ajoûterai encore, qu’il faut obſerver de ne point faire leurs travées <lb/>ſi longues qu’on ſoit obligé d’employer pluſieurs piéces pour la <lb/>Tablette, ce qui eſt contraire à la bonne grace & </s> <s xml:id="echoid-s11416" xml:space="preserve">à la ſolidité; </s> <s xml:id="echoid-s11417" xml:space="preserve">car <lb/>rien n’eſt ſi ſec que de voir 15 ou 20 Baluſtres de ſuite ſans Pila-<lb/>ſtres & </s> <s xml:id="echoid-s11418" xml:space="preserve">ſans aucune liaiſon, ainſi je croi que 9 ou 10 au plus par <lb/>travées doivent ſuffire.</s> <s xml:id="echoid-s11419" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11420" xml:space="preserve">L’on met quelquefois dans le milieu des Places Publiques des <lb/>Piramides, qui ſont des Monumens fervant à tranſmettre à la poſte-<lb/>rité la Memoire des grands Princes: </s> <s xml:id="echoid-s11421" xml:space="preserve">on les orne ordinairement <lb/>d’un Trophée d’Armes, de Figures, de Bas-Reliefs, qui repreſen-<lb/>tent leurs actions mémorables, leurs victoires, leur vertu, leur <lb/>puiſſance, & </s> <s xml:id="echoid-s11422" xml:space="preserve">les Ennemis qu’ils ont vaincus.</s> <s xml:id="echoid-s11423" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11424" xml:space="preserve">Une Piramide doit être d’une hauteur qui l’éleve au-deſſus de <lb/>tous les Bâtimens des environs; </s> <s xml:id="echoid-s11425" xml:space="preserve">enſorte même qu’elle ſoit vûë de <lb/>la Campagne, & </s> <s xml:id="echoid-s11426" xml:space="preserve">qu’elle faſſe un riche ornement pour la Ville ou <lb/>elle ſera érigée. </s> <s xml:id="echoid-s11427" xml:space="preserve">Il faut prendre garde auſſi qu’une Piramide doit <lb/>être ſeule, autrement elle perdroit ſa véritable ſignification, qui <lb/>eſt de repréſenter la gloire du Prince qui regne ou qui a regné.</s> <s xml:id="echoid-s11428" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11429" xml:space="preserve">Je ne finirois jamais, ſi je voulois parler de tout ce qui peut ap-<lb/>partenir à la Décoration des Edifices: </s> <s xml:id="echoid-s11430" xml:space="preserve">ce ſujet eſt ſi abondant, que <lb/>plus on l’examine, & </s> <s xml:id="echoid-s11431" xml:space="preserve">plus l’on trouve matiere à de nouvelles re-<lb/>flexions. </s> <s xml:id="echoid-s11432" xml:space="preserve">L’inclination, dont je me ſens animé pour l’inſtruction des <lb/>Lecteurs, fait que je voudrois ne leur rien laiſſer à déſirer, & </s> <s xml:id="echoid-s11433" xml:space="preserve">leur <lb/>donner au moins une connoiſſance generale de tout ce qui peut <lb/>s’offrir aux yeux; </s> <s xml:id="echoid-s11434" xml:space="preserve">cependant, je ſuis ſouvent contraint de retenir ma <lb/>plume, crainte qu’on ne la trouve point aſſés intereſſante, & </s> <s xml:id="echoid-s11435" xml:space="preserve">qu’on ne <lb/>ſe plaigne que je m’arrête à des choſes qui paroiſſent trop éloignées <pb o="80" file="0546" n="596" rhead="LA SCIENCE DES INGENIEURS."/> de mon ſujet: </s> <s xml:id="echoid-s11436" xml:space="preserve">il ne faut pourtant pas croire que c’eſt la paſſion d’é-<lb/>crire qui me guide; </s> <s xml:id="echoid-s11437" xml:space="preserve">je me ſuis preſcrit des bornes, & </s> <s xml:id="echoid-s11438" xml:space="preserve">elles paroî-<lb/>tront peut être trop étroites, quand on entrera bien dans mes ſenti-<lb/>mens, car voici comme j’ai raiſonné en compoſant ce 5<emph style="sub">e</emph>. </s> <s xml:id="echoid-s11439" xml:space="preserve">Livre.</s> <s xml:id="echoid-s11440" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11441" xml:space="preserve">L’ouvrage que je veux donner au Public a pour objet l’Inſtruc-<lb/>tion des jeunes Ingenieurs, & </s> <s xml:id="echoid-s11442" xml:space="preserve">de tous ceux qui ont la conduite des <lb/>Travaux pour le Roy ou pour les Particuliers: </s> <s xml:id="echoid-s11443" xml:space="preserve">les uns & </s> <s xml:id="echoid-s11444" xml:space="preserve">les autres <lb/>parlent ſans ceſſe Bâtimens; </s> <s xml:id="echoid-s11445" xml:space="preserve">& </s> <s xml:id="echoid-s11446" xml:space="preserve">je ſai par experience qu’on n’en <lb/>peut raiſonner juſte, ſans en avoir fait une longue & </s> <s xml:id="echoid-s11447" xml:space="preserve">pénible étude: <lb/></s> <s xml:id="echoid-s11448" xml:space="preserve">peu de gens ont aſſés de loiſir & </s> <s xml:id="echoid-s11449" xml:space="preserve">aſſés de courage pour lire 25 ou <lb/>30 gros Volumes, qu’on ne peut avoir qu’en faiſant des dépenſes <lb/>conſidérables dont on n’eſt pas toûjours à portée, & </s> <s xml:id="echoid-s11450" xml:space="preserve">que ce ſeroit <lb/>leur abreger beaucoup de chemin de leur donner en peu de mots <lb/>tout ce qui pourroit contribuer à les mettre en état, non-ſeulement <lb/>de travailler par eux-mêmes, mais de porter un jugement ſolide <lb/>de tous les Edifices qui méritent quelqu’attention, ſoit que leur <lb/>profeſſion les y engage, ou ſeulement pour ſatisfaire leur curioſité, <lb/>principalement ſur un ſujet qui étant purement de goût, tout le <lb/>monde ſe croit en droit de blàmer ou d’aplaudir. </s> <s xml:id="echoid-s11451" xml:space="preserve">Je me ſuis donc <lb/>chargé de toute la peine que pouvoit donner le ſoin de débroüiller <lb/>& </s> <s xml:id="echoid-s11452" xml:space="preserve">de mettre en Ordre les Penſées & </s> <s xml:id="echoid-s11453" xml:space="preserve">les Principes de tant d’Au-<lb/>teurs differens, dans l’eſperance qu’on ſeroit ſatisfait du motif qui <lb/>me guide.</s> <s xml:id="echoid-s11454" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div478" type="section" level="1" n="129"> <head xml:id="echoid-head343" style="it" xml:space="preserve">Fin du cinquiéme Livre.</head> <figure> <image file="0546-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0546-01"/> </figure> <pb file="0547" n="597"/> <figure> <image file="0547-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0547-01"/> </figure> </div> <div xml:id="echoid-div479" type="section" level="1" n="130"> <head xml:id="echoid-head344" xml:space="preserve">LA SCIENCE <lb/>DES INGENIEURS <lb/>DANS LA CONDUITE DES TRAVAUX <lb/>DE FORTIFICATION.</head> <head xml:id="echoid-head345" xml:space="preserve">LIVRE SIXIE’ME.</head> <p style="it"> <s xml:id="echoid-s11455" xml:space="preserve">Qui comprend la Maniere de faire les Devis pour la con-<lb/>ſtruction des Fortifications, & </s> <s xml:id="echoid-s11456" xml:space="preserve">celle des Bâtimens civils.</s> <s xml:id="echoid-s11457" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11458" xml:space="preserve"><emph style="sc">COmme</emph> l’on ne peut bien faire les Devis, ſans avoir <lb/>une connoiſſance parfaite des ouvrages quel’on veut <lb/>exécuter, il m’a paru qu’il convenoit de ne traiter <lb/>cette matiere qu’aprèsavoir enſeigné tout ce quel’on <lb/>a vû dans les quatre premiers Livres: </s> <s xml:id="echoid-s11459" xml:space="preserve">car pour bien <lb/>dreſſer un Devis, il faut non-ſeulement ſçavoir faire <lb/>un bon choix des matériaux, afin de ſpécifier les conditions de <lb/>ceux que l’on voudra employer, & </s> <s xml:id="echoid-s11460" xml:space="preserve">la maniere de les mettre en <lb/>œuvre; </s> <s xml:id="echoid-s11461" xml:space="preserve">mais il faut encore régler les dimenſions des ouvrages, <lb/>afin qu’on puiſſe voir toutes les particularités du projet juſques dans <pb o="2" file="0548" n="598" rhead="LA SCIENCE DES INGENIEURS,"/> les moindres parties. </s> <s xml:id="echoid-s11462" xml:space="preserve">C’eſt dans un Devis qu’un Ingénieur habile <lb/>peut donner des marques de ſa capacité, & </s> <s xml:id="echoid-s11463" xml:space="preserve">c’eſt en effet l’endroit <lb/>par lequel on peut en juger ſûrement; </s> <s xml:id="echoid-s11464" xml:space="preserve">car s’il a du goût & </s> <s xml:id="echoid-s11465" xml:space="preserve">de bons <lb/>principes d’Architecture militaire & </s> <s xml:id="echoid-s11466" xml:space="preserve">civile, il le fera voir par les <lb/>dimenſions qui ſeront preſcrites dans ſon Devis; </s> <s xml:id="echoid-s11467" xml:space="preserve">s’il a l’eſprit net <lb/>& </s> <s xml:id="echoid-s11468" xml:space="preserve">juſte, on y appercevra un Ordre & </s> <s xml:id="echoid-s11469" xml:space="preserve">un Arrangement qui rendront <lb/>intereſſans les ſujets les plus ingrats; </s> <s xml:id="echoid-s11470" xml:space="preserve">enfin s’il eſt capable de faire <lb/>exécuter les travaux les plus difficiles, on en ſera convaincu par <lb/>les détails bien circonſtanciés de tout ce qui doit entrer dans leur <lb/>conſtruction: </s> <s xml:id="echoid-s11471" xml:space="preserve">ſa pénétration ira même juſqu’à prévoir les accidens <lb/>qui pourroient ſurvenir, & </s> <s xml:id="echoid-s11472" xml:space="preserve">rien ne lui échapera. </s> <s xml:id="echoid-s11473" xml:space="preserve">On peut donc <lb/>dire qu’un Devis doit être regardé commele chef d’œuvre de l’In-<lb/>génieur, & </s> <s xml:id="echoid-s11474" xml:space="preserve">que c’eſt de-là que dépend abfolument l’exécution <lb/>bonne ou mauvaiſe du deſſein que l’on a en vûë. </s> <s xml:id="echoid-s11475" xml:space="preserve">Combien de fois <lb/>n’eſt-il pas arrivé que de grands ouvrages ont échoüé faute d’avoir <lb/>été précédés d’un bon Devis? </s> <s xml:id="echoid-s11476" xml:space="preserve">Et que ne pourroit-on pas alléguer <lb/>pour en prouver la conſequence?</s> <s xml:id="echoid-s11477" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11478" xml:space="preserve">Dans l’uſage ordinaire ce ſont Meſſieurs les Directeurs de For-<lb/>tifications qui font les Devis, & </s> <s xml:id="echoid-s11479" xml:space="preserve">le plus ſouvent les Ingénieurs en <lb/>chef; </s> <s xml:id="echoid-s11480" xml:space="preserve">mais comme il n’y a point d’Ingénieurs qui ne puiſſent ſe <lb/>trouver dans le cas de projetter par eux-mêmes, on peut regarder <lb/>ce ſixiéme Livre comme celui qu’il importe le plus de bien ſça-<lb/>voir, puiſque, comme je l’ai déja dit, les autres qui précedent <lb/>n’en ſont que l’Introduction.</s> <s xml:id="echoid-s11481" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11482" xml:space="preserve">Le Devis eſt un Mémoire inſtructif de toutes les parties d’un ou-<lb/>vrage qu’on veut conſtruire; </s> <s xml:id="echoid-s11483" xml:space="preserve">il explique l’Ordre & </s> <s xml:id="echoid-s11484" xml:space="preserve">la Conduite du <lb/>travail, les qualités & </s> <s xml:id="echoid-s11485" xml:space="preserve">façons des matériaux, & </s> <s xml:id="echoid-s11486" xml:space="preserve">géneralement tout <lb/>ce qui a rapport à la conſtruction & </s> <s xml:id="echoid-s11487" xml:space="preserve">à la perfection de l’ouvrage.</s> <s xml:id="echoid-s11488" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11489" xml:space="preserve">Ses qualités principales ſont que toutes les matieres ſoient miſes <lb/>dans un bel Ordre, énoncées clairement & </s> <s xml:id="echoid-s11490" xml:space="preserve">bien détaillées, ſans <lb/>confuſion, n’omettant rien d’eſſentiel, & </s> <s xml:id="echoid-s11491" xml:space="preserve">de ne laiſſer aucun équi-<lb/>voque qui puiſſe donner lieu dans la ſuite à des conteſtations avec <lb/>les Entrepreneurs; </s> <s xml:id="echoid-s11492" xml:space="preserve">il doit être relatif au plan & </s> <s xml:id="echoid-s11493" xml:space="preserve">profil du projet: <lb/></s> <s xml:id="echoid-s11494" xml:space="preserve">quand il eſt revêtu de toutes ces conditions, il ſert de guide à l’En-<lb/>trepreneur, aux ouvriers, & </s> <s xml:id="echoid-s11495" xml:space="preserve">à l’Ingénieur même, parce qu’alors il <lb/>aſſujettit les uns & </s> <s xml:id="echoid-s11496" xml:space="preserve">les autres à travailler de concert & </s> <s xml:id="echoid-s11497" xml:space="preserve">conformé-<lb/>ment à l’intention du Directeur, ou de celui qui a fait le projet.</s> <s xml:id="echoid-s11498" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11499" xml:space="preserve">Il n’y a point de ſorte d’ouvrage qui ne demande ſon Devis par-<lb/>ticulier; </s> <s xml:id="echoid-s11500" xml:space="preserve">mais comme il faudroit un détail infini pour en circonſ-<lb/>tancier chaque eſpece, je me contenterai d’en donner une idée ge-<lb/>nerale qui ſuffira pour en faire l’application à toute ſorte de tra- <pb o="3" file="0549" n="599" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> vaux, & </s> <s xml:id="echoid-s11501" xml:space="preserve">à ceux même dont je ne ferai point mention; </s> <s xml:id="echoid-s11502" xml:space="preserve">pour cela <lb/>nous ſuppoſerons, comme nous l’avons fait juſqu’ici, qu’il s’agit <lb/>de bâtir une Place neuve dont tous les deſſeins ſont cottés & </s> <s xml:id="echoid-s11503" xml:space="preserve">réglés <lb/>définitivement, & </s> <s xml:id="echoid-s11504" xml:space="preserve">qu’il n’eſt plus queſtion que d’en faire le Devis <lb/>pour enſuite proceder à l’adjudication: </s> <s xml:id="echoid-s11505" xml:space="preserve">en rempliſſant ce deſſein <lb/>je remettrai ſous les yeux du Lecteur toutes les differentes eſpeces <lb/>d’ouvrages dont j’ai fait mention juſqu’ici; </s> <s xml:id="echoid-s11506" xml:space="preserve">mais, avant cela il eſt à <lb/>propos que je m’arrête un moment pour faire voir la diſpoſition <lb/>générale d’un Devis tel que celui dont nous parlons.</s> <s xml:id="echoid-s11507" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11508" xml:space="preserve">Il faut commencer d’abord par faire mention de la ſituation de <lb/>la Place & </s> <s xml:id="echoid-s11509" xml:space="preserve">de ſon tracé, des principales pieces de fortifications qui <lb/>doivent compoſer ſon enceinte, comme du corps de la Place, des <lb/>ouvrages détachés & </s> <s xml:id="echoid-s11510" xml:space="preserve">des chemins couverts, on doit dire un mot <lb/>en paſſant des meſures qu’il faudra prendre pour établir le Rez-<lb/>de-chauſſée général, & </s> <s xml:id="echoid-s11511" xml:space="preserve">pour former la diſtribution des ruës, de-là <lb/>on paſſe aux dimenſions de chaque eſpece d’ouvrage, commençant <lb/>par le corps de la Place, & </s> <s xml:id="echoid-s11512" xml:space="preserve">continuant par les autres ouvrages dé-<lb/>tachés, & </s> <s xml:id="echoid-s11513" xml:space="preserve">cela à meſure qu’il s’éloigne du centre; </s> <s xml:id="echoid-s11514" xml:space="preserve">on fait mention <lb/>des épaiſſeurs que doivent avoir les murs au ſommet & </s> <s xml:id="echoid-s11515" xml:space="preserve">ſur la baſe, <lb/>de leurs taluds, retraites & </s> <s xml:id="echoid-s11516" xml:space="preserve">empatemens, de la hauteur & </s> <s xml:id="echoid-s11517" xml:space="preserve">épaiſ-<lb/>ſeur des contreforts, de la largeur & </s> <s xml:id="echoid-s11518" xml:space="preserve">profondeur des foſſez, de la <lb/>diſpoſition des chemins couverts & </s> <s xml:id="echoid-s11519" xml:space="preserve">glacis, des voûtes, portes, ſou-<lb/>terrains & </s> <s xml:id="echoid-s11520" xml:space="preserve">latrines, le tout en géneral ſeulement; </s> <s xml:id="echoid-s11521" xml:space="preserve">& </s> <s xml:id="echoid-s11522" xml:space="preserve">c’eſt ce qui <lb/>doit faire la premiere partie du Devis.</s> <s xml:id="echoid-s11523" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11524" xml:space="preserve">On entre enſuite dans le détail de la qualité des matériaux, com-<lb/>me des mortiers, ciment, ſable, chaux, pierre de taille, moëlon, <lb/>pierres de parement, carreaux & </s> <s xml:id="echoid-s11525" xml:space="preserve">boutiſſes, joints, hauteur des <lb/>aſſiſes, libages, fichages des pierres, fer, bois, pilotis, placage & </s> <s xml:id="echoid-s11526" xml:space="preserve"><lb/>gazonage, ce qui forme la ſeconde partie; </s> <s xml:id="echoid-s11527" xml:space="preserve">& </s> <s xml:id="echoid-s11528" xml:space="preserve">on continuë en re-<lb/>prenant chaque ouvrage l’un après l’autre ſuivant l’Ordre de ſa conſ-<lb/>truction particuliere, détaillant toutes les précautions, aſſujettiſ-<lb/>ſemens, formes & </s> <s xml:id="echoid-s11529" xml:space="preserve">règles du travail dans toutes leurs circonſtan-<lb/>ces, obſervant toûjours de commencer par le corps de la Place, <lb/>comme il vient d’être dit, & </s> <s xml:id="echoid-s11530" xml:space="preserve">d’en épuiſer la matiere avant que de <lb/>paſſer aux autres ouvrages, qu’on doit enſuite traiter tour-à-tour <lb/>avec la même méthode.</s> <s xml:id="echoid-s11531" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11532" xml:space="preserve">Enfin le Devis ſe termine par la conſtruction des Ponts, Puits, <lb/>Magaſins, Arſenaux, Hôpitaux, Pavillons, & </s> <s xml:id="echoid-s11533" xml:space="preserve">Corps de Cazernes, <lb/>quoique cependant il ſoit d’uſage de faire un Devis particulier pour <lb/>ces derniers; </s> <s xml:id="echoid-s11534" xml:space="preserve">en tout cas, on doit garder le même ordre pour ces <lb/>ſortes de bâtimens, que pour la Place même, c’eſt-à-dire, déſigner <pb o="4" file="0550" n="600" rhead="LA SCIENCE DES INGENIEURS,"/> d’abord leurs dimenſions principales, parler enſuite de la qualité <lb/>des matériaux, & </s> <s xml:id="echoid-s11535" xml:space="preserve">ſuivre après en détail l’Ordre de leur conſtruc-<lb/>tion, commençant par les gros ouvrages, & </s> <s xml:id="echoid-s11536" xml:space="preserve">finiſſant par les legers, <lb/>après quoi l’on met les conditions qui regardent les Entrepre-<lb/>neurs.</s> <s xml:id="echoid-s11537" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11538" xml:space="preserve">Voilà ce qu’on peut dire en général ſur l’Ordre & </s> <s xml:id="echoid-s11539" xml:space="preserve">l’Arrangement <lb/>des parties d’un Devis. </s> <s xml:id="echoid-s11540" xml:space="preserve">Quant aux autres qualités qu’il demande <lb/>pour être bien fait, elles ſe réduiſent, comme je l’ai déja dit, à la <lb/>netteté & </s> <s xml:id="echoid-s11541" xml:space="preserve">à la préciſion, c’eſt-à-dire, à diſtinguer chaque choſe <lb/>clairement, à ne rien oublier d’eſſentiel, de même qu’à ne rien <lb/>mettre d’inutile; </s> <s xml:id="echoid-s11542" xml:space="preserve">à ne point faire des répétitions qu’autant qu’elles <lb/>ſont abſolument néceſſaires pour un plus parfait éclairciſſement, <lb/>à ne laiſſer aucun équivoque ou doute qui puiſſe donner matiere <lb/>aux Entrepreneurs de conteſter, & </s> <s xml:id="echoid-s11543" xml:space="preserve">à ſpécifier toûjours autant qu’il <lb/>eſt poſſible, la qualité & </s> <s xml:id="echoid-s11544" xml:space="preserve">la force de chaque nature d’ouvrage, <lb/>afin que l’Entrepreneur ſoit obligé de s’y aſſujettir, & </s> <s xml:id="echoid-s11545" xml:space="preserve">que non <lb/>ſeulement on ſoit en droit de lui faire éxécuter ſon marché dans <lb/>toutes ſes circonſtances, mais encore qu’il ne puiſſe trouver aucun <lb/>faux-fuyant pour ſe diſculper des frais que le plus ou moins de <lb/>propreté dans l’ouvrage, ou le plus ou moins de force dans cha-<lb/>que choſe, pourroit occaſionner.</s> <s xml:id="echoid-s11546" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11547" xml:space="preserve">Il ne faut pas non plus dans un Devis multiplier les titres mal à <lb/>propos, ce défaut le rend ordinairement obſcur, & </s> <s xml:id="echoid-s11548" xml:space="preserve">lui ôte cet air <lb/>de netteté qu’il doit avoir. </s> <s xml:id="echoid-s11549" xml:space="preserve">Il vaut beaucoup mieux renfermer ſous <lb/>un ſeul titre toutes les matieres qui peuvent y avoir rapport, & </s> <s xml:id="echoid-s11550" xml:space="preserve"><lb/>les apoſtiller à la marge chacune en particulier, afin qu’on les puiſ-<lb/>ſe trouver du premier coup d’œil, quand l’occaſion le demande.</s> <s xml:id="echoid-s11551" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11552" xml:space="preserve">J’ai tâché de me conformer dans le modele ſuivant aux régles <lb/>que je viens de preſcrire, & </s> <s xml:id="echoid-s11553" xml:space="preserve">la lecture ſera plus inſtructive qu’un <lb/>plus ample diſcours. </s> <s xml:id="echoid-s11554" xml:space="preserve">On y trouvera la plûpart des dimenſions & </s> <s xml:id="echoid-s11555" xml:space="preserve"><lb/>des conditions qui ont été obſervées au Neuf-Briſac, que j’ai choi-<lb/>ſi exprès préferablement à toute autre Place, à cauſe de l’eſtime <lb/>que l’on fait de la beauté de ſes ouvrages. </s> <s xml:id="echoid-s11556" xml:space="preserve">C’eſt effectivement le <lb/>ſujet le plus parfait qui puiſſe être traité; </s> <s xml:id="echoid-s11557" xml:space="preserve">cependant, je ne m’aſſu-<lb/>jettirai point au Devis primitif qui en a été fait, quoique je le pren-<lb/>drois ſans balancer pour unique modele, ſi cet abregé me permet-<lb/>toit d’entrer dans tout ſon détail.</s> <s xml:id="echoid-s11558" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11559" xml:space="preserve">J’ai ajoûté à la fin de ce Devis deux planches qui ſerviront à dé-<lb/>velopper la Fortification du Neuf-Briſac; </s> <s xml:id="echoid-s11560" xml:space="preserve">les Tours baſtionnées, qui <lb/>ſont repréſentées ſur la ſeconde, ne ſont point tout-à-fait confor-<lb/>mes à celles qui ont été exécutées, parce que je les ai tirées d’un <pb o="5" file="0551" n="601" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> nouveau projet que M. </s> <s xml:id="echoid-s11561" xml:space="preserve">le Marêchal de Vauban a fait quelqu’an-<lb/>nées avant ſa mort, pour rectifier celui du Neuf-Briſac; </s> <s xml:id="echoid-s11562" xml:space="preserve">mais com-<lb/>me la difference eſt très peu de choſe, j’ai crû qu’au lieu d’y trou-<lb/>ver à redire, on me ſçauroit bon gré d’avoir rapporté celles-ci pré-<lb/>ferablement aux autres qui ſont connuës de tout le monde; </s> <s xml:id="echoid-s11563" xml:space="preserve">d’ail-<lb/>leurs il eſt bon que l’on ſçache que ces deux planches, que j’ai fait <lb/>graver il y a pluſieurs années, ne devoient point ſe trouver dans <lb/>ce Volume-ci, leur veritable place étant dans celui où je parle de <lb/>l’art de fortifier les Places, & </s> <s xml:id="echoid-s11564" xml:space="preserve">de la maniere de faire les projets de <lb/>Fortification, que je mettrai au jour dans la ſuite; </s> <s xml:id="echoid-s11565" xml:space="preserve">c’eſt pourquoi <lb/>elles contiennent des lettres & </s> <s xml:id="echoid-s11566" xml:space="preserve">des chiffres deſquels je ne fais point <lb/>mention preſentement, parce qu’ils ont rapport à un diſcours qui <lb/>n’eſt pas du ſujet que je traite ici; </s> <s xml:id="echoid-s11567" xml:space="preserve">mais ſans s’en mettre en peine, <lb/>il ſuffira en liſant ce Devis de jetter de tems en tems les yeux ſur <lb/>les deſſeins, afin d’avoir une parfaite intelligence de l’objet de cha-<lb/>que article, & </s> <s xml:id="echoid-s11568" xml:space="preserve">on ne trouvera pas moins ces deux planches avec <lb/>leur Diſſertation dans le Volume dont je viens de parler.</s> <s xml:id="echoid-s11569" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div480" type="section" level="1" n="131"> <head xml:id="echoid-head346" xml:space="preserve">MODELE D’UN DEVIS POUR UNE PLACE <lb/>neuve, telle que le Neuf-Briſac.</head> <p style="it"> <s xml:id="echoid-s11570" xml:space="preserve">Devis des Ouvrages de Maçonnerie, Terre & </s> <s xml:id="echoid-s11571" xml:space="preserve">Gazonnages, <lb/>Charpente, Couverture, Menuiſerie & </s> <s xml:id="echoid-s11572" xml:space="preserve">autres que le Roy a <lb/>ordonné être faits pour la Conſtruction d’une nouvelle Place. <lb/></s> <s xml:id="echoid-s11573" xml:space="preserve">On marque ici ſon nom & </s> <s xml:id="echoid-s11574" xml:space="preserve">ſa ſituation.</s> <s xml:id="echoid-s11575" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div481" type="section" level="1" n="132"> <head xml:id="echoid-head347" xml:space="preserve">I. <lb/><emph style="sc">Situation de la</emph> <emph style="sc">Place</emph>.</head> <p> <s xml:id="echoid-s11576" xml:space="preserve">LA Place ſera ſituée dans la plaine de.</s> <s xml:id="echoid-s11577" xml:space="preserve">..</s> <s xml:id="echoid-s11578" xml:space="preserve">. ou ſur la riviere de.</s> <s xml:id="echoid-s11579" xml:space="preserve">.. <lb/></s> <s xml:id="echoid-s11580" xml:space="preserve"> <anchor type="note" xlink:label="note-0551-01a" xlink:href="note-0551-01"/> & </s> <s xml:id="echoid-s11581" xml:space="preserve">ſera tracée ſuivant les meſures de ſon plan en octogone ré-<lb/>gulier, formant huit poligones égaux; </s> <s xml:id="echoid-s11582" xml:space="preserve">ſur chaque angle deſquels <lb/>ſera conſtruite une Tour baſtionnée ſuivant les dimenſions qui ſe-<lb/>ront ſpécifiées ci-après.</s> <s xml:id="echoid-s11583" xml:space="preserve"/> </p> <div xml:id="echoid-div481" type="float" level="2" n="1"> <note position="right" xlink:label="note-0551-01" xlink:href="note-0551-01a" xml:space="preserve">Figure & <lb/>ſituation de <lb/>la Place.</note> </div> <p> <s xml:id="echoid-s11584" xml:space="preserve">Les dehors de la Place conſiſteront en huit baſtions détachés, ou <lb/> <anchor type="note" xlink:label="note-0551-02a" xlink:href="note-0551-02"/> contregardes tracés ſur la capitale de ces Tours, huit tenailles de-<lb/>vant les courtines, huit réduits, huit demi-lunes devant ces ré-<lb/>duits, & </s> <s xml:id="echoid-s11585" xml:space="preserve">un ouvrage à corne devant tel.</s> <s xml:id="echoid-s11586" xml:space="preserve">..</s> <s xml:id="echoid-s11587" xml:space="preserve">. front; </s> <s xml:id="echoid-s11588" xml:space="preserve">le tout envelop-<lb/>pé d’un chemin couvert.</s> <s xml:id="echoid-s11589" xml:space="preserve"/> </p> <div xml:id="echoid-div482" type="float" level="2" n="2"> <note position="right" xlink:label="note-0551-02" xlink:href="note-0551-02a" xml:space="preserve">Dehors de <lb/>la Place.</note> </div> <pb o="6" file="0552" n="602" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s11590" xml:space="preserve">Après que la Place aura été tracée, on fera courir le niveau <lb/> <anchor type="note" xlink:label="note-0552-01a" xlink:href="note-0552-01"/> tout au tour, & </s> <s xml:id="echoid-s11591" xml:space="preserve">ſur ſes differentes élevations on prendra un mi-<lb/>lieu pour établir le Rez-de-chauſſée, ce qui ſe fera en abaiſſant les <lb/>parties les plus élevées, & </s> <s xml:id="echoid-s11592" xml:space="preserve">en relevant celles qui ſe trouveront <lb/>trop baſſes. </s> <s xml:id="echoid-s11593" xml:space="preserve">Ce même niveau réglera ceux de dedans & </s> <s xml:id="echoid-s11594" xml:space="preserve">du dehors <lb/>de la Place.</s> <s xml:id="echoid-s11595" xml:space="preserve"/> </p> <div xml:id="echoid-div483" type="float" level="2" n="3"> <note position="left" xlink:label="note-0552-01" xlink:href="note-0552-01a" xml:space="preserve">Rez-de-<lb/>chauſſée.</note> </div> <p> <s xml:id="echoid-s11596" xml:space="preserve">On fera en même tems la diſtribution des ruës qui doivent ſépa-<lb/> <anchor type="note" xlink:label="note-0552-02a" xlink:href="note-0552-02"/> rer les Places à bâtir, & </s> <s xml:id="echoid-s11597" xml:space="preserve">on en marquera la deſtination par de <lb/>grands piquets auſquels ſeront attachés des écriteaux de fer-blanc <lb/>qui ſerviront d’indices; </s> <s xml:id="echoid-s11598" xml:space="preserve">& </s> <s xml:id="echoid-s11599" xml:space="preserve">pour avoir les pentes néceſſaires à l’é-<lb/>coulement des eaux, on relevera le centre de la Place de quatre <lb/>pieds, & </s> <s xml:id="echoid-s11600" xml:space="preserve">on chiffrera des piquets fixes qui régleront l’alignement <lb/>des ruës, & </s> <s xml:id="echoid-s11601" xml:space="preserve">indiqueront les rehauſſemens ou rabaiſſemens qu’il y <lb/>aura à faire à chaque partie.</s> <s xml:id="echoid-s11602" xml:space="preserve"/> </p> <div xml:id="echoid-div484" type="float" level="2" n="4"> <note position="left" xlink:label="note-0552-02" xlink:href="note-0552-02a" xml:space="preserve">Diſtribu-<lb/>tion des <lb/>ruës & pen-<lb/>tes pour l’é-<lb/>coulement <lb/>des eaux.</note> </div> </div> <div xml:id="echoid-div486" type="section" level="1" n="133"> <head xml:id="echoid-head348" xml:space="preserve">II. <lb/>DIMENSIONS DES PARTIES PRINCIPALES <lb/>de la Place.</head> <head xml:id="echoid-head349" style="it" xml:space="preserve">CORPS DE LA PLACE.</head> <head xml:id="echoid-head350" xml:space="preserve"><emph style="sc">Poligone et</emph> <emph style="sc">Courtine</emph>.</head> <p> <s xml:id="echoid-s11603" xml:space="preserve">CHaque Poligone extérieur aura 180 toiſes de longueur d’un <lb/> <anchor type="note" xlink:label="note-0552-03a" xlink:href="note-0552-03"/> angle à l’autre.</s> <s xml:id="echoid-s11604" xml:space="preserve"/> </p> <div xml:id="echoid-div486" type="float" level="2" n="1"> <note position="left" xlink:label="note-0552-03" xlink:href="note-0552-03a" xml:space="preserve">Poligone.</note> </div> <p> <s xml:id="echoid-s11605" xml:space="preserve">Les Courtines auront 124 toiſes 4 pieds {3/4} chacune entre les <lb/> <anchor type="note" xlink:label="note-0552-04a" xlink:href="note-0552-04"/> Tours, & </s> <s xml:id="echoid-s11606" xml:space="preserve">ſeront coupées en deux endroits par des flancs de 4 toi-<lb/>ſes 4 pieds, formées par le prolongement de ceux des contre-<lb/>gardes.</s> <s xml:id="echoid-s11607" xml:space="preserve"/> </p> <div xml:id="echoid-div487" type="float" level="2" n="2"> <note position="left" xlink:label="note-0552-04" xlink:href="note-0552-04a" xml:space="preserve">Courtines.</note> </div> <p> <s xml:id="echoid-s11608" xml:space="preserve">Leur revêtement aura dix pieds deux pouces d’épaiſſeur au <lb/> <anchor type="note" xlink:label="note-0552-05a" xlink:href="note-0552-05"/> deſſus des fondemens, y compris le chanfrain des trois aſſiſes de <lb/>pierre de taille, & </s> <s xml:id="echoid-s11609" xml:space="preserve">ſera élevé de trente pieds depuis le deſſus des <lb/>fondemens juſqu’à la hauteur du deſſus du cordon, où l’épaiſſeur <lb/>ſera réduite à cinq.</s> <s xml:id="echoid-s11610" xml:space="preserve"/> </p> <div xml:id="echoid-div488" type="float" level="2" n="3"> <note position="left" xlink:label="note-0552-05" xlink:href="note-0552-05a" xml:space="preserve">Revétemens <lb/>des Courti-<lb/>nes.</note> </div> <p> <s xml:id="echoid-s11611" xml:space="preserve">Au niveau du fond du foſſé ſera faite une retraite de trois pou-<lb/> <anchor type="note" xlink:label="note-0552-06a" xlink:href="note-0552-06"/> ces de ſaillie au dehors du nud dudit revêtement, & </s> <s xml:id="echoid-s11612" xml:space="preserve">un peu audeſ-<lb/>ſous une autre pareille retraite, de ſorte que les fondemens auront <lb/>dix pieds huit pouces d’épaiſſeur par le bas, ſur trois pieds de pro-<lb/>fondeur. </s> <s xml:id="echoid-s11613" xml:space="preserve">On obſervera les même retraites, empatemens tant des <lb/>Tours baſtionnées que des contregardes, tenailles, demi-lunes, <lb/>réduits & </s> <s xml:id="echoid-s11614" xml:space="preserve">autres pieces, ainſi il n’en ſera plus parlé dans la ſuite.</s> <s xml:id="echoid-s11615" xml:space="preserve"/> </p> <div xml:id="echoid-div489" type="float" level="2" n="4"> <note position="left" xlink:label="note-0552-06" xlink:href="note-0552-06a" xml:space="preserve">Retraites <lb/>& fonde-<lb/>mens.</note> </div> <pb o="7" file="0553" n="603" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s11616" xml:space="preserve">Les Contreforts ſeront conſtruits auſſi bas que le revêtement, <lb/> <anchor type="note" xlink:label="note-0553-01a" xlink:href="note-0553-01"/> & </s> <s xml:id="echoid-s11617" xml:space="preserve">élevés à même hauteur, on les eſpacera à quinze pieds de diſ-<lb/>tance les uns des autres de milieu en milieu, & </s> <s xml:id="echoid-s11618" xml:space="preserve">ils auront huit <lb/>pieds de long, cinq de large à la racine, & </s> <s xml:id="echoid-s11619" xml:space="preserve">trois à la queue.</s> <s xml:id="echoid-s11620" xml:space="preserve"/> </p> <div xml:id="echoid-div490" type="float" level="2" n="5"> <note position="right" xlink:label="note-0553-01" xlink:href="note-0553-01a" xml:space="preserve">Contre-<lb/>forts.</note> </div> <p> <s xml:id="echoid-s11621" xml:space="preserve">Pour ſuppléer aux affaiſſemens des terres, les Remparts ſeront <lb/> <anchor type="note" xlink:label="note-0553-02a" xlink:href="note-0553-02"/> élevés de trois pieds plus de la hauteur des revêtemens, & </s> <s xml:id="echoid-s11622" xml:space="preserve">la ſur-<lb/>face de leur terre-plain ſera dreſſée ſur trente pieds de largeur en <lb/>pente d’un pied & </s> <s xml:id="echoid-s11623" xml:space="preserve">demi à prendre depuis la banquette juſqu’au ta-<lb/>lud intérieur des mêmes remparts, qui aura les deux tiers de ſa <lb/>hauteur; </s> <s xml:id="echoid-s11624" xml:space="preserve">ces Remparts ſeront ornés de deux rangs d’arbres qui <lb/>formeront une allée ſur le terre-plain, & </s> <s xml:id="echoid-s11625" xml:space="preserve">d’un troiſiéme qui ſera <lb/>planté au pied du talud du rempart.</s> <s xml:id="echoid-s11626" xml:space="preserve"/> </p> <div xml:id="echoid-div491" type="float" level="2" n="6"> <note position="right" xlink:label="note-0553-02" xlink:href="note-0553-02a" xml:space="preserve">Rempart@.</note> </div> <p> <s xml:id="echoid-s11627" xml:space="preserve">La Banquette aura quatre pieds & </s> <s xml:id="echoid-s11628" xml:space="preserve">demi de large ſur un pied & </s> <s xml:id="echoid-s11629" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0553-03a" xlink:href="note-0553-03"/> demi de haut, taluant de trois pieds.</s> <s xml:id="echoid-s11630" xml:space="preserve"/> </p> <div xml:id="echoid-div492" type="float" level="2" n="7"> <note position="right" xlink:label="note-0553-03" xlink:href="note-0553-03a" xml:space="preserve">Banquette.</note> </div> <p> <s xml:id="echoid-s11631" xml:space="preserve">Les Parapets auront dix-huit pieds d’épaiſſeur au ſommet, & </s> <s xml:id="echoid-s11632" xml:space="preserve">ſe-<lb/>ront élevés pardevant de quatre pieds au-deſſus du cordon, & </s> <s xml:id="echoid-s11633" xml:space="preserve">de <lb/>quatre pieds & </s> <s xml:id="echoid-s11634" xml:space="preserve">demi au-deſſus de la Banquette, formant une pen-<lb/>te de deux pieds & </s> <s xml:id="echoid-s11635" xml:space="preserve">demi du derriere au devant. </s> <s xml:id="echoid-s11636" xml:space="preserve">Le talud du ga-<lb/>zonnage intérieur ſera du quart de ſa hauteur.</s> <s xml:id="echoid-s11637" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div494" type="section" level="1" n="134"> <head xml:id="echoid-head351" xml:space="preserve"><emph style="sc">Tours</emph> <emph style="sc">Bastionne’es</emph>.</head> <p> <s xml:id="echoid-s11638" xml:space="preserve">Chaque Tour ſera compoſée de deux faces, deux flancs, & </s> <s xml:id="echoid-s11639" xml:space="preserve">une <lb/> <anchor type="note" xlink:label="note-0553-04a" xlink:href="note-0553-04"/> gorge de Maçonnerie; </s> <s xml:id="echoid-s11640" xml:space="preserve">chaque face aura deux toiſes cinq pieds <lb/>huit pouces de long, meſurés au cordon; </s> <s xml:id="echoid-s11641" xml:space="preserve">chaque flanc ſix toiſes; <lb/></s> <s xml:id="echoid-s11642" xml:space="preserve">chaque demi-gorge ſept, & </s> <s xml:id="echoid-s11643" xml:space="preserve">la capitale neuf toiſes deux pieds ſix <lb/>pouces.</s> <s xml:id="echoid-s11644" xml:space="preserve"/> </p> <div xml:id="echoid-div494" type="float" level="2" n="1"> <note position="right" xlink:label="note-0553-04" xlink:href="note-0553-04a" xml:space="preserve">Tours baſ-<lb/>tionnées.</note> </div> <p> <s xml:id="echoid-s11645" xml:space="preserve">Son revêtement ſera élevé de vingt-huit pieds depuis le deſſus <lb/> <anchor type="note" xlink:label="note-0553-05a" xlink:href="note-0553-05"/> des fondemens où il y aura treize pieds un pouce d’épaiſſeur, juſ-<lb/>qu’au cordon où l’épaiſſeur ſe réduira à huit pieds, & </s> <s xml:id="echoid-s11646" xml:space="preserve">ſera ſur-<lb/>monté d’un Parapet de maçonnerie de briques auſſi de huit pieds <lb/>d’épaiſſeur & </s> <s xml:id="echoid-s11647" xml:space="preserve">de ſix de hauteur, dans lequel ſeront obſervées, auſſi <lb/>bien qu’à l’étage inferieur, toutes les embraſures, évents, & </s> <s xml:id="echoid-s11648" xml:space="preserve">Gué-<lb/>rites marqués dans les Plans & </s> <s xml:id="echoid-s11649" xml:space="preserve">Profils.</s> <s xml:id="echoid-s11650" xml:space="preserve"/> </p> <div xml:id="echoid-div495" type="float" level="2" n="2"> <note position="right" xlink:label="note-0553-05" xlink:href="note-0553-05a" xml:space="preserve">Revéte-<lb/>ment & p@-<lb/>rape@.</note> </div> <p> <s xml:id="echoid-s11651" xml:space="preserve">On élevera le long des faces deux Banquettes de maçonnerie, <lb/> <anchor type="note" xlink:label="note-0553-06a" xlink:href="note-0553-06"/> faiſant enſemble trois pieds de largeur ſur trois de hauteur.</s> <s xml:id="echoid-s11652" xml:space="preserve"/> </p> <div xml:id="echoid-div496" type="float" level="2" n="3"> <note position="right" xlink:label="note-0553-06" xlink:href="note-0553-06a" xml:space="preserve">Banquett<unsure/>e<unsure/>.</note> </div> <p> <s xml:id="echoid-s11653" xml:space="preserve">Le mur des gorges n’aura que ſix pieds d’épaiſſeur au-deſſus des <lb/> <anchor type="note" xlink:label="note-0553-07a" xlink:href="note-0553-07"/> fondemens, & </s> <s xml:id="echoid-s11654" xml:space="preserve">ſera érigé à plomb juſqu’à la hauteur du ſommet <lb/>du Parapet des Tours.</s> <s xml:id="echoid-s11655" xml:space="preserve"/> </p> <div xml:id="echoid-div497" type="float" level="2" n="4"> <note position="right" xlink:label="note-0553-07" xlink:href="note-0553-07a" xml:space="preserve">Gorges.</note> </div> <p> <s xml:id="echoid-s11656" xml:space="preserve">Au centre de chacune de ces Tours ſera fait un noyau de ma-<lb/> <anchor type="note" xlink:label="note-0553-08a" xlink:href="note-0553-08"/> çonnerie fondé auſſi-bas que le revêtement, pour recevoir & </s> <s xml:id="echoid-s11657" xml:space="preserve">ſou- <pb o="8" file="0554" n="604" rhead="LA SCIENCE DES INGENIEURS,"/> tenir les voûtes qui regneront le long des flancs & </s> <s xml:id="echoid-s11658" xml:space="preserve">gorges; </s> <s xml:id="echoid-s11659" xml:space="preserve">ces <lb/>voûtes auront dix-huit pieds de longueur de vuide, & </s> <s xml:id="echoid-s11660" xml:space="preserve">ſeront conſ-<lb/>truites à plein-ceintre. </s> <s xml:id="echoid-s11661" xml:space="preserve">Au milieu du noyau ſera pratiqué un Ma-<lb/>gazin à poudre voûté auſſi à plein-ceintre de quinze pieds de lar-<lb/>geur dans œuvre & </s> <s xml:id="echoid-s11662" xml:space="preserve">de vingt pieds de longueur.</s> <s xml:id="echoid-s11663" xml:space="preserve"/> </p> <div xml:id="echoid-div498" type="float" level="2" n="5"> <note position="right" xlink:label="note-0553-08" xlink:href="note-0553-08a" xml:space="preserve">Noyau & <lb/>Voûtes.</note> </div> <p> <s xml:id="echoid-s11664" xml:space="preserve">Il ſera fait aux deux côtés de chaque Tour une poterne voûtée <lb/> <anchor type="note" xlink:label="note-0554-01a" xlink:href="note-0554-01"/> pour communiquer aux contregardes, dont les allées débouche-<lb/>ront dans le foſſé à côté des flancs, & </s> <s xml:id="echoid-s11665" xml:space="preserve">auront ſix pieds de largeur <lb/>chacune juſqu’à la jonction du gros mur de la courtine, où le paſ-<lb/>ſage de la porte ſera maſqué de maçonnerie pour n’être ouverte <lb/>que dans le beſoin, & </s> <s xml:id="echoid-s11666" xml:space="preserve">réduit à quatre pieds & </s> <s xml:id="echoid-s11667" xml:space="preserve">demi. </s> <s xml:id="echoid-s11668" xml:space="preserve">Le mur qui <lb/>ſoutiendra les terres du côté du Rempart, aura cinq pieds d’é-<lb/>paiſſeur au-deſſus des fondemens, où ſera faite une retraite de trois <lb/>pouces de chaque côté, & </s> <s xml:id="echoid-s11669" xml:space="preserve">cinq pieds & </s> <s xml:id="echoid-s11670" xml:space="preserve">demi de hauteur juſqu’à <lb/>la naiſſance des voûtes.</s> <s xml:id="echoid-s11671" xml:space="preserve"/> </p> <div xml:id="echoid-div499" type="float" level="2" n="6"> <note position="left" xlink:label="note-0554-01" xlink:href="note-0554-01a" xml:space="preserve">Poternes.</note> </div> <p> <s xml:id="echoid-s11672" xml:space="preserve">Le paſſage de l’entrée inferieure des Tours ſera auſſi voûté ſur <lb/> <anchor type="note" xlink:label="note-0554-02a" xlink:href="note-0554-02"/> douze pieds de largeur à l’endroit du rempart, & </s> <s xml:id="echoid-s11673" xml:space="preserve">formé par deux <lb/>murs qui auront chacun cinq pieds & </s> <s xml:id="echoid-s11674" xml:space="preserve">demi d’épaiſſeur au-deſſus <lb/>de leurs fondemens, avec trois pouces de retraite de chaque cô-<lb/>té, & </s> <s xml:id="echoid-s11675" xml:space="preserve">quatre pieds de hauteur au-deſſus du rez-de-chauſſée de <lb/>l’interieur des Tours. </s> <s xml:id="echoid-s11676" xml:space="preserve">Ces murs ſeront ſoutenus du côté des terres <lb/>par des contreforts de ſix pieds de longeur, quatre & </s> <s xml:id="echoid-s11677" xml:space="preserve">demi de <lb/>largeur à la racine, & </s> <s xml:id="echoid-s11678" xml:space="preserve">trois à la queuë.</s> <s xml:id="echoid-s11679" xml:space="preserve"/> </p> <div xml:id="echoid-div500" type="float" level="2" n="7"> <note position="left" xlink:label="note-0554-02" xlink:href="note-0554-02a" xml:space="preserve">Paſſage & <lb/>l’entrée des <lb/>Tours.</note> </div> <p> <s xml:id="echoid-s11680" xml:space="preserve">A l’entrée de ces paſſages, & </s> <s xml:id="echoid-s11681" xml:space="preserve">ſur l’alignement du retour du rem-<lb/> <anchor type="note" xlink:label="note-0554-03a" xlink:href="note-0554-03"/> part, ſera faite une porte de pierre de taille avec les fermetures <lb/>de huit pieds de longeur, & </s> <s xml:id="echoid-s11682" xml:space="preserve">neuf & </s> <s xml:id="echoid-s11683" xml:space="preserve">demi de hauteur ſous clef, <lb/>dont les pieds droits ſeront prolongez en dehors juſqu’au pied <lb/>du talud du rempart, formant deux aîles en rampe ſuivant le mê-<lb/>me talud, qui auront trois pieds d’épaiſſeur chacune aux extremi-<lb/>tez avec des ébraſſemens de part & </s> <s xml:id="echoid-s11684" xml:space="preserve">d’autre; </s> <s xml:id="echoid-s11685" xml:space="preserve">& </s> <s xml:id="echoid-s11686" xml:space="preserve">à chaque côté de <lb/>cette entrée ſera fait un eſcalier de pierre de taille, dont les mar-<lb/>ches auront quatre pieds & </s> <s xml:id="echoid-s11687" xml:space="preserve">demi de longueur ſur ſix pouces de <lb/>hauteur, contregardé par un petit mur d’appui de deux pieds d’é-<lb/>paiſſeur.</s> <s xml:id="echoid-s11688" xml:space="preserve"/> </p> <div xml:id="echoid-div501" type="float" level="2" n="8"> <note position="left" xlink:label="note-0554-03" xlink:href="note-0554-03a" xml:space="preserve">Porte de <lb/>l’entrée des <lb/>Tours & <lb/>eſcalier.</note> </div> </div> <div xml:id="echoid-div503" type="section" level="1" n="135"> <head xml:id="echoid-head352" xml:space="preserve">GRANDES PORTES ET CORPS DE GARDE <lb/><emph style="sc">DES</emph> <emph style="sc">Entre’es principales</emph>.</head> <p> <s xml:id="echoid-s11689" xml:space="preserve">Sur le milieu des quatre courtines qui répondront aux entrées <lb/> <anchor type="note" xlink:label="note-0554-04a" xlink:href="note-0554-04"/> principales de la Place, ſera fait quatre grandes Portes d’Archi-<lb/>tecture. </s> <s xml:id="echoid-s11690" xml:space="preserve">La hauteur du frontiſpice de chaque porte ſera de huit <pb o="9" file="0555" n="605" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> toiſes depuis le deſſus des fondemens juſqu’au deſſus de la corniche <lb/>de l’entablement, & </s> <s xml:id="echoid-s11691" xml:space="preserve">ſa largeur de huit toiſes trois pieds au deſſus <lb/>du ſoubaſſement, ſur onze pieds d’épaiſſeur par le bas, & </s> <s xml:id="echoid-s11692" xml:space="preserve">ſept par le <lb/>haut, non compris la ſaillie des pilaſtres. </s> <s xml:id="echoid-s11693" xml:space="preserve">Le fronton aura douze <lb/>pieds d’élevation dans ſon milieu. </s> <s xml:id="echoid-s11694" xml:space="preserve">Chaque porte aura neuf pieds <lb/>neuf pouces de largeur entre les pieds droits, treize pieds de hau-<lb/>teur entre le ſeuil & </s> <s xml:id="echoid-s11695" xml:space="preserve">la clef, & </s> <s xml:id="echoid-s11696" xml:space="preserve">ſera décorée conformément au deſ-<lb/>ſein.</s> <s xml:id="echoid-s11697" xml:space="preserve"/> </p> <div xml:id="echoid-div503" type="float" level="2" n="1"> <note position="left" xlink:label="note-0554-04" xlink:href="note-0554-04a" xml:space="preserve">Portès <lb/>d’Architec-<lb/>ture.</note> </div> <p> <s xml:id="echoid-s11698" xml:space="preserve">Le paſſage des entrées aura douze pieds de largeur dans œuvre <lb/> <anchor type="note" xlink:label="note-0555-01a" xlink:href="note-0555-01"/> entre les doſſerets, non compris la refuite des côtés. </s> <s xml:id="echoid-s11699" xml:space="preserve">Il ſera voûté <lb/>au deſſus de l’impoſte, & </s> <s xml:id="echoid-s11700" xml:space="preserve">formé par des murs de cinq pieds de hau-<lb/>teur juſqu’audit impoſte, & </s> <s xml:id="echoid-s11701" xml:space="preserve">cinq pieds & </s> <s xml:id="echoid-s11702" xml:space="preserve">demi d’épaiſſeur au deſ-<lb/>ſus de leur fondement, faiſant retraite de trois pouces de part & </s> <s xml:id="echoid-s11703" xml:space="preserve"><lb/>d’autre. </s> <s xml:id="echoid-s11704" xml:space="preserve">Ces murs ſeront ſoutenus de chaque côté par deux con-<lb/>treforts qui auront chacun ſix pieds de longueur, cinq de largeur <lb/>à la racine, & </s> <s xml:id="echoid-s11705" xml:space="preserve">trois à la queuë. </s> <s xml:id="echoid-s11706" xml:space="preserve">Ce paſſage ſera garni de toutes ſes <lb/>fermetures, ponts-levis, orgues, & </s> <s xml:id="echoid-s11707" xml:space="preserve">baſcules conformement au deſ-<lb/>ſein, & </s> <s xml:id="echoid-s11708" xml:space="preserve">ſera précedé d’un periſtile ou veſtibule de trente huit pieds <lb/> <anchor type="note" xlink:label="note-0555-02a" xlink:href="note-0555-02"/> de largeur dans un ſens, & </s> <s xml:id="echoid-s11709" xml:space="preserve">vingt-un & </s> <s xml:id="echoid-s11710" xml:space="preserve">demi dans l’autre, qui ſera <lb/>voûté à même hauteur que le paſſage de la porte, & </s> <s xml:id="echoid-s11711" xml:space="preserve">ſoûtenu par <lb/>des doſſerets & </s> <s xml:id="echoid-s11712" xml:space="preserve">piliers de pierre de taille de trois pieds ſur trois & </s> <s xml:id="echoid-s11713" xml:space="preserve"><lb/>demi d’épaiſſeur, cimetriſant avec la Décoration des pieds droits <lb/>du paſſage.</s> <s xml:id="echoid-s11714" xml:space="preserve"/> </p> <div xml:id="echoid-div504" type="float" level="2" n="2"> <note position="right" xlink:label="note-0555-01" xlink:href="note-0555-01a" xml:space="preserve">Paſſage.</note> <note position="right" xlink:label="note-0555-02" xlink:href="note-0555-02a" xml:space="preserve">Veſtibule.</note> </div> <p> <s xml:id="echoid-s11715" xml:space="preserve">La partie de ce periſtile, qui regarde le dedans de la Place, ſera <lb/>revêtuë de pierre de taille dedans & </s> <s xml:id="echoid-s11716" xml:space="preserve">dehors ſur toute ſa hauteur, <lb/>& </s> <s xml:id="echoid-s11717" xml:space="preserve">aura cinq pieds d’épaiſſeur au deſſus des fondemens; </s> <s xml:id="echoid-s11718" xml:space="preserve">elle fera <lb/>retraite de deux pouces à deux pieds au deſſus de ces fondemens, <lb/>puis élevée de ſeize pieds depuis le deſſus de cette retraite juſqu’au <lb/>deſſus du plinthe, formant trois arcades dont celle du milieu aura <lb/>dix pieds d’ouverture, & </s> <s xml:id="echoid-s11719" xml:space="preserve">les deux joignantes huit pieds ſeulement; <lb/></s> <s xml:id="echoid-s11720" xml:space="preserve">toutes trois de quatorze pieds de hauteur.</s> <s xml:id="echoid-s11721" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11722" xml:space="preserve">A droite & </s> <s xml:id="echoid-s11723" xml:space="preserve">à gauche du même periſtile ſeront faits deux Corps <lb/> <anchor type="note" xlink:label="note-0555-03a" xlink:href="note-0555-03"/> de garde & </s> <s xml:id="echoid-s11724" xml:space="preserve">une Priſon, dont les murs de face & </s> <s xml:id="echoid-s11725" xml:space="preserve">de retour auront <lb/>quatre pieds & </s> <s xml:id="echoid-s11726" xml:space="preserve">demi d’épaiſſeur au-deſſus de toutes les retraites; <lb/></s> <s xml:id="echoid-s11727" xml:space="preserve">ces pieces ſeront éclairées par quatre croiſées de quatre pieds de <lb/>largeur & </s> <s xml:id="echoid-s11728" xml:space="preserve">huit de hauteur chacune, diſpoſée & </s> <s xml:id="echoid-s11729" xml:space="preserve">décorée avec <lb/>ſimetrie, deux de chaque côté du veſtibule, & </s> <s xml:id="echoid-s11730" xml:space="preserve">auront enſemble <lb/>dix toiſes un pied de longueur de face du côté de la Place.</s> <s xml:id="echoid-s11731" xml:space="preserve"/> </p> <div xml:id="echoid-div505" type="float" level="2" n="3"> <note position="right" xlink:label="note-0555-03" xlink:href="note-0555-03a" xml:space="preserve">Corps d@ <lb/>garde.</note> </div> <p> <s xml:id="echoid-s11732" xml:space="preserve">Le logement au-deſſus ſera conforme en tout à la diſtribution <lb/> <anchor type="note" xlink:label="note-0555-04a" xlink:href="note-0555-04"/> figurée dans le deſſein; </s> <s xml:id="echoid-s11733" xml:space="preserve">& </s> <s xml:id="echoid-s11734" xml:space="preserve">ſa façade, qui ſera percée de neuf croi-<lb/>ſées, & </s> <s xml:id="echoid-s11735" xml:space="preserve">réduites à deux pieds d’épaiſſeur, ſera élevée de dix-ſept <pb o="10" file="0556" n="606" rhead="LA SCIENCE DES INGENIEURS,"/> pieds depuis le deſſus du plinthe juſqu’au deſſus de l’entablement; <lb/></s> <s xml:id="echoid-s11736" xml:space="preserve">le tout décoré ſuivant les élevations du même deſſein, & </s> <s xml:id="echoid-s11737" xml:space="preserve">ſurmonté <lb/>d’un fronton, de quatre lucarnes, & </s> <s xml:id="echoid-s11738" xml:space="preserve">d’un comble de ſeize pieds de <lb/>hauteur. </s> <s xml:id="echoid-s11739" xml:space="preserve">La chambre aux orgues, la cage de baſcule, & </s> <s xml:id="echoid-s11740" xml:space="preserve">les eſca-<lb/>liers à droite & </s> <s xml:id="echoid-s11741" xml:space="preserve">à gauche des portes pour monter ſur le rempart, <lb/>ſeront auſſi conſtruits ſuivant leur plans & </s> <s xml:id="echoid-s11742" xml:space="preserve">profils particuliers. </s> <s xml:id="echoid-s11743" xml:space="preserve">Ces <lb/>eſcaliers ſeront de pierre de taille, ils auront quatre pieds & </s> <s xml:id="echoid-s11744" xml:space="preserve">demi <lb/>de largeur dans œuvre, & </s> <s xml:id="echoid-s11745" xml:space="preserve">un mur d’apui rempant de deux pieds <lb/>& </s> <s xml:id="echoid-s11746" xml:space="preserve">demi d’épaiſſeur.</s> <s xml:id="echoid-s11747" xml:space="preserve"/> </p> <div xml:id="echoid-div506" type="float" level="2" n="4"> <note position="right" xlink:label="note-0555-04" xlink:href="note-0555-04a" xml:space="preserve">Lo<unsure/>gement <lb/>audeſſus & <lb/>chambre <lb/>aux orgues.</note> </div> </div> <div xml:id="echoid-div508" type="section" level="1" n="136"> <head xml:id="echoid-head353" xml:space="preserve"><emph style="sc">Poternes de</emph> <emph style="sc">Sortie</emph>.</head> <p> <s xml:id="echoid-s11748" xml:space="preserve">Dansle milieu de chaque courtine où il n’y aura point de gran-<lb/> <anchor type="note" xlink:label="note-0556-01a" xlink:href="note-0556-01"/> de porte, ſera faite une poterne pour communiquer aux tenailles; <lb/></s> <s xml:id="echoid-s11749" xml:space="preserve">l’on y deſcendra par un eſcalier de pierre de taille hors œuvre, <lb/>voûté ſur ſix pieds de largeur, & </s> <s xml:id="echoid-s11750" xml:space="preserve">ſurmonté à l’aplomb du talud <lb/>ſuperieur du rempart, d’un mur de brique d’un pied & </s> <s xml:id="echoid-s11751" xml:space="preserve">demi d’é-<lb/>paiſſeur, & </s> <s xml:id="echoid-s11752" xml:space="preserve">de quatre de hauteur au deſſus du terre-plain.</s> <s xml:id="echoid-s11753" xml:space="preserve"/> </p> <div xml:id="echoid-div508" type="float" level="2" n="1"> <note position="left" xlink:label="note-0556-01" xlink:href="note-0556-01a" xml:space="preserve">Poternes <lb/>de ſortie.</note> </div> <p> <s xml:id="echoid-s11754" xml:space="preserve">Son paſſage ſera enfoncé de cinq pieds au deſſus du ſol de la <lb/> <anchor type="note" xlink:label="note-0556-02a" xlink:href="note-0556-02"/> Place, & </s> <s xml:id="echoid-s11755" xml:space="preserve">aura douze pieds de largeur. </s> <s xml:id="echoid-s11756" xml:space="preserve">Ses portes, ainſi que celles <lb/>des poternes des Tours baſtionnées, auront quatre pieds & </s> <s xml:id="echoid-s11757" xml:space="preserve">demi <lb/>de largeur, & </s> <s xml:id="echoid-s11758" xml:space="preserve">ſeront garnies de leurs fermetures d’une force con-<lb/>venable, obſervant de les maſquer toutes enſuite du côté du foſſé <lb/>d’une bonne maçonnerie de quatre pieds à quatre pieds & </s> <s xml:id="echoid-s11759" xml:space="preserve">demi <lb/>d’épaiſſeur, & </s> <s xml:id="echoid-s11760" xml:space="preserve">de pratiquer un petit évent dans ce maſque.</s> <s xml:id="echoid-s11761" xml:space="preserve"/> </p> <div xml:id="echoid-div509" type="float" level="2" n="2"> <note position="left" xlink:label="note-0556-02" xlink:href="note-0556-02a" xml:space="preserve">Paſſage.</note> </div> <p> <s xml:id="echoid-s11762" xml:space="preserve">Les pieds droits de ce paſſage auront ſix pieds de hauteur & </s> <s xml:id="echoid-s11763" xml:space="preserve">cinq <lb/>d’épaiſſeur au-deſſus de leurs fondemens, faiſant retraite de trois <lb/>pouces de chaque côté, & </s> <s xml:id="echoid-s11764" xml:space="preserve">ſeront ſoûtenus par des contreforts de <lb/>trois pieds de large à la racine, deux à la queuë, & </s> <s xml:id="echoid-s11765" xml:space="preserve">quatre & </s> <s xml:id="echoid-s11766" xml:space="preserve">de-<lb/>mi de long.</s> <s xml:id="echoid-s11767" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11768" xml:space="preserve">Et pour faciliter l’écoulement des eaux de la Place, ſera conſ-<lb/> <anchor type="note" xlink:label="note-0556-03a" xlink:href="note-0556-03"/> truit au deſſous de ces Poternes un petit Aqueduc voûté de deux <lb/>pieds de largeur dans œuvre, ſur trois de hauteur, dont les pieds <lb/>droits auront chacun deux pieds & </s> <s xml:id="echoid-s11769" xml:space="preserve">demi d’épaiſſeur. </s> <s xml:id="echoid-s11770" xml:space="preserve">On en fera <lb/>de pareils à chaque côté des quatre grandes portes.</s> <s xml:id="echoid-s11771" xml:space="preserve"/> </p> <div xml:id="echoid-div510" type="float" level="2" n="3"> <note position="left" xlink:label="note-0556-03" xlink:href="note-0556-03a" xml:space="preserve">@quedue.</note> </div> </div> <div xml:id="echoid-div512" type="section" level="1" n="137"> <head xml:id="echoid-head354" xml:space="preserve"><emph style="sc">Souterrains</emph>.</head> <p> <s xml:id="echoid-s11772" xml:space="preserve">Il ſera fait des ſouterrains ſous les briſures de chaque courtine, <lb/> <anchor type="note" xlink:label="note-0556-04a" xlink:href="note-0556-04"/> qui feront l’office de flanc bas, à l’exception de deux ſeulement, <lb/>qui ſeront conduits en pente douce, & </s> <s xml:id="echoid-s11773" xml:space="preserve">perceront du dedans de la <pb o="11" file="0557" n="607" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> Place juſqu’au fond du foſſé, pour y abreuver les chevaux en tems <lb/>de Siége. </s> <s xml:id="echoid-s11774" xml:space="preserve">Ces ſouterrains ſeront pavés proprement, & </s> <s xml:id="echoid-s11775" xml:space="preserve">fermés par <lb/>des portes ſûres à chaque extrémité, puis murées ſolidement pour <lb/>n’être ouvertes que dans les beſoins preſſans; </s> <s xml:id="echoid-s11776" xml:space="preserve">ils auront dix-huit <lb/>pieds de largeur dans œuvre, leurs pieds droits ſept pieds & </s> <s xml:id="echoid-s11777" xml:space="preserve">demi <lb/>juſqu’à la naiſſance des voûtes, & </s> <s xml:id="echoid-s11778" xml:space="preserve">quatre pieds & </s> <s xml:id="echoid-s11779" xml:space="preserve">demi d’épaiſ-<lb/>ſeur, leurs contreforts ſix pieds de longueur, quatre de largeur à <lb/>la racine, & </s> <s xml:id="echoid-s11780" xml:space="preserve">trois à la queuë.</s> <s xml:id="echoid-s11781" xml:space="preserve"/> </p> <div xml:id="echoid-div512" type="float" level="2" n="1"> <note position="left" xlink:label="note-0556-04" xlink:href="note-0556-04a" xml:space="preserve">Souter-<lb/>@ains.</note> </div> <p> <s xml:id="echoid-s11782" xml:space="preserve">Pour deſcendre dans les premiers de ces ſouterrains, on prati-<lb/> <anchor type="note" xlink:label="note-0557-01a" xlink:href="note-0557-01"/> quera intérieurement à leur entrée un eſcalier de pierre de taille <lb/>de ſept pieds de largeur, fondé ſur un bon maſſif avec des murs <lb/>d’apui d’un pied & </s> <s xml:id="echoid-s11783" xml:space="preserve">demi d’épaiſſeur. </s> <s xml:id="echoid-s11784" xml:space="preserve">Les pieds droits de cette entrée <lb/>ſeront prolongés par dehors juſqu’au pied du talud du rempart, & </s> <s xml:id="echoid-s11785" xml:space="preserve"><lb/>ébraſés de ſix pieds de chaque côté. </s> <s xml:id="echoid-s11786" xml:space="preserve">Ils auront cinq pieds d’épaiſ-<lb/>ſeur au deſſus des fondemens, & </s> <s xml:id="echoid-s11787" xml:space="preserve">ſeront réduits à trois à leur ſom-<lb/>met. </s> <s xml:id="echoid-s11788" xml:space="preserve">On obſervera de pratiquer dans un des pieds droits de ces <lb/>ſouterrains, & </s> <s xml:id="echoid-s11789" xml:space="preserve">contiguëment à l’entrée, un petit magazin à poudre <lb/>de huit ſur douze pieds de largeur dans œuvre, & </s> <s xml:id="echoid-s11790" xml:space="preserve">d’élever ſur cette <lb/>entrée un petit mur d’un pied & </s> <s xml:id="echoid-s11791" xml:space="preserve">demi d’épaiſſeur qui ſurmonte de <lb/>trois à quatre pieds le terre-plein du rempart. </s> <s xml:id="echoid-s11792" xml:space="preserve">On obſervera de <lb/>même toutes les cheminées, évens, & </s> <s xml:id="echoid-s11793" xml:space="preserve">embraſures qui ſont marqués <lb/>dans le plan.</s> <s xml:id="echoid-s11794" xml:space="preserve"/> </p> <div xml:id="echoid-div513" type="float" level="2" n="2"> <note position="right" xlink:label="note-0557-01" xlink:href="note-0557-01a" xml:space="preserve">Eſcalier.</note> </div> </div> <div xml:id="echoid-div515" type="section" level="1" n="138"> <head xml:id="echoid-head355" xml:space="preserve"><emph style="sc">Bastions detache’s, ou</emph> <emph style="sc">Contregardes</emph>.</head> <p> <s xml:id="echoid-s11795" xml:space="preserve">Les faces des contregardes auront ſoixante toiſes de longueur <lb/> <anchor type="note" xlink:label="note-0557-02a" xlink:href="note-0557-02"/> chacune, & </s> <s xml:id="echoid-s11796" xml:space="preserve">les flancs vingt-deux. </s> <s xml:id="echoid-s11797" xml:space="preserve">Ces faces & </s> <s xml:id="echoid-s11798" xml:space="preserve">ces flancs ſeront <lb/>élevés à demi-revêtement depuis le deſſus de leurs fondemens, & </s> <s xml:id="echoid-s11799" xml:space="preserve"><lb/>auront dix-huit pieds de hauteur à l’angle du flanc & </s> <s xml:id="echoid-s11800" xml:space="preserve">de la <lb/> <anchor type="note" xlink:label="note-0557-03a" xlink:href="note-0557-03"/> gorge, dix-huit & </s> <s xml:id="echoid-s11801" xml:space="preserve">demi à celui de l’épaule, & </s> <s xml:id="echoid-s11802" xml:space="preserve">vingt à l’angle flan-<lb/>qué, taluant d’un ſur ſix; </s> <s xml:id="echoid-s11803" xml:space="preserve">ce revêtement aura ſept pieds huit pou-<lb/>ces d’épaiſſeur au deſſus des fondemens, & </s> <s xml:id="echoid-s11804" xml:space="preserve">à trois pieds près du ſom-<lb/>met dudit revêtement; </s> <s xml:id="echoid-s11805" xml:space="preserve">la maçonnerie ſera arrangée & </s> <s xml:id="echoid-s11806" xml:space="preserve">réduite par <lb/>ſon talud à cinq pieds d’épaiſſeur. </s> <s xml:id="echoid-s11807" xml:space="preserve">Les trois autres pieds d’élevation <lb/>ſeront continués ſuivant le talud du parement exterieur ſur trois <lb/>pieds d’épaiſſeur par le bas, revenant à deux pieds & </s> <s xml:id="echoid-s11808" xml:space="preserve">demi au ſom-<lb/>met.</s> <s xml:id="echoid-s11809" xml:space="preserve"/> </p> <div xml:id="echoid-div515" type="float" level="2" n="1"> <note position="right" xlink:label="note-0557-02" xlink:href="note-0557-02a" xml:space="preserve">Faces & <lb/>flancs des <lb/>contregar-<lb/>des.</note> <note position="right" xlink:label="note-0557-03" xlink:href="note-0557-03a" xml:space="preserve">Executé <lb/>à Briſac.</note> </div> <p> <s xml:id="echoid-s11810" xml:space="preserve">Sur-tout on aura ſoin d’élever ſur chaque angle flanqué un petit <lb/>mur en forme de ſurtout de quarante-deux pieds de longueur, & </s> <s xml:id="echoid-s11811" xml:space="preserve"><lb/>de quatre & </s> <s xml:id="echoid-s11812" xml:space="preserve">demi de hauteur, dont le couronnement ſe racordera <lb/>à celui des faces par une rechûte en talud de douze pieds.</s> <s xml:id="echoid-s11813" xml:space="preserve"/> </p> <pb o="12" file="0558" n="608" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s11814" xml:space="preserve">Le revêtement des gorges aura deux pieds & </s> <s xml:id="echoid-s11815" xml:space="preserve">demi d’épaiſſeur au <lb/> <anchor type="note" xlink:label="note-0558-01a" xlink:href="note-0558-01"/> ſommet, & </s> <s xml:id="echoid-s11816" xml:space="preserve">ſeize de hauteur à prendre depuis le deſſus des fonde-<lb/>mens, il taluera auſſi d’un ſur ſix, & </s> <s xml:id="echoid-s11817" xml:space="preserve">ſuivra le profil des parapets, <lb/>banquettes, & </s> <s xml:id="echoid-s11818" xml:space="preserve">remparts.</s> <s xml:id="echoid-s11819" xml:space="preserve"/> </p> <div xml:id="echoid-div516" type="float" level="2" n="2"> <note position="left" xlink:label="note-0558-01" xlink:href="note-0558-01a" xml:space="preserve">Gorges.</note> </div> <p> <s xml:id="echoid-s11820" xml:space="preserve">Les contreforts des flancs & </s> <s xml:id="echoid-s11821" xml:space="preserve">des faces auront les mêmes dimen-<lb/> <anchor type="note" xlink:label="note-0558-02a" xlink:href="note-0558-02"/> ſions que ceux des courtines, & </s> <s xml:id="echoid-s11822" xml:space="preserve">ſeront eſpacés du même inter-<lb/>valle. </s> <s xml:id="echoid-s11823" xml:space="preserve">On les élevera à trois pieds près du ſommet des revêtemens. <lb/></s> <s xml:id="echoid-s11824" xml:space="preserve">Ceux des gorges n’auront que quatre pieds de longueur, trois d’é-<lb/>paiſſeur à la racine, & </s> <s xml:id="echoid-s11825" xml:space="preserve">deux à la queuë, & </s> <s xml:id="echoid-s11826" xml:space="preserve">ſeront d’un pied plus <lb/>bas que le ſommet des gorges.</s> <s xml:id="echoid-s11827" xml:space="preserve"/> </p> <div xml:id="echoid-div517" type="float" level="2" n="3"> <note position="left" xlink:label="note-0558-02" xlink:href="note-0558-02a" xml:space="preserve">Contre-<lb/>forts.</note> </div> <p> <s xml:id="echoid-s11828" xml:space="preserve">Au niveau de la brique-de-cant qui terminera le revêtement des <lb/> <anchor type="note" xlink:label="note-0558-03a" xlink:href="note-0558-03"/> flancs & </s> <s xml:id="echoid-s11829" xml:space="preserve">des faces, ſera faite une berme de dix pieds de largeur, <lb/>ſur laquelle on plantera une haye vive, après quoi on continuëra <lb/>l’élevation des remparts & </s> <s xml:id="echoid-s11830" xml:space="preserve">des parapets de ces pieces, en parement <lb/>de gazon ou avec placage ſeulement, en taluant des deux tiers <lb/>de la hauteur. </s> <s xml:id="echoid-s11831" xml:space="preserve">L’interieur de ces parapets auſſi bien que les ban-<lb/>quettes ſeront en tout ſemblables à ce qui a été dit pour ceux du <lb/>corps de la Place, & </s> <s xml:id="echoid-s11832" xml:space="preserve">leur extérieur ſurmontera de quatre pieds le <lb/>niveau du terre-plein du rempart.</s> <s xml:id="echoid-s11833" xml:space="preserve"/> </p> <div xml:id="echoid-div518" type="float" level="2" n="4"> <note position="left" xlink:label="note-0558-03" xlink:href="note-0558-03a" xml:space="preserve">Berme & <lb/>parapet.</note> </div> <p> <s xml:id="echoid-s11834" xml:space="preserve">Ces remparts auront trente pieds de largeur depuis le bord de <lb/> <anchor type="note" xlink:label="note-0558-04a" xlink:href="note-0558-04"/> leur talud interieur juſqu’au pied de la banquette, à l’endroit de <lb/>laquelle ils ſeront élevés de dix pieds au deſſus de la berme des ou-<lb/>vrages avec pente d’un pied & </s> <s xml:id="echoid-s11835" xml:space="preserve">demi du côté de la Place, obſer-<lb/>vant de les élever d’un pied plus à l’angle de l’épaule, qu’à celui <lb/>du flanc & </s> <s xml:id="echoid-s11836" xml:space="preserve">de la gorge, & </s> <s xml:id="echoid-s11837" xml:space="preserve">de trois pieds à l’angle flanqué plus <lb/>qu’à celui de l’épaule. </s> <s xml:id="echoid-s11838" xml:space="preserve">Dans cette hauteur de dix pieds ſont com-<lb/>pris les trois pieds qu’on donnera pour ſuppléer aux affaiſſemens des <lb/>terres, & </s> <s xml:id="echoid-s11839" xml:space="preserve">ces mêmes dix pieds joints aux quatre pieds du parapet <lb/>donneront en tout quatorze pieds de hauteur par devant de gazon-<lb/>nage ou placage. </s> <s xml:id="echoid-s11840" xml:space="preserve">L’on obſervera auſſi les rempes néceſſaires pour <lb/>la montée du canon, & </s> <s xml:id="echoid-s11841" xml:space="preserve">elles auront onze toiſes de longueur ſur <lb/>neuf pieds de largeur.</s> <s xml:id="echoid-s11842" xml:space="preserve"/> </p> <div xml:id="echoid-div519" type="float" level="2" n="5"> <note position="left" xlink:label="note-0558-04" xlink:href="note-0558-04a" xml:space="preserve">Remparts.</note> </div> <p> <s xml:id="echoid-s11843" xml:space="preserve">Il ſera fait un ſouterrain ſous le rempart de chaque flanc, pour com-<lb/> <anchor type="note" xlink:label="note-0558-05a" xlink:href="note-0558-05"/> muniquer aux tenailles; </s> <s xml:id="echoid-s11844" xml:space="preserve">ſon paſſage ſera conduit en pente depuis <lb/>l’interieur des contregardes juſqu’au niveau de la rempe, quiſera pri-<lb/>ſe dans ces mêmes tenailles huit pieds au deſſus des fondemens, il aura <lb/>ſix pieds de largeur, & </s> <s xml:id="echoid-s11845" xml:space="preserve">ſes pieds droits auront trois pieds d’épaiſ-<lb/>ſeur, & </s> <s xml:id="echoid-s11846" xml:space="preserve">cinq de hauteur juſqu’à la naiſſance des voûtes. </s> <s xml:id="echoid-s11847" xml:space="preserve">L’entrée de <lb/>ces ſouterrains ſera formée par un mur élevé à l’aplomb du talud ſu-<lb/>perieur du rempart par un profil de dixhuit pieds de longueur. </s> <s xml:id="echoid-s11848" xml:space="preserve">Ces <lb/>deux murs ſeront érigés perpendiculairement, & </s> <s xml:id="echoid-s11849" xml:space="preserve">auront chacun <lb/>trois pieds d’épaiſſeur.</s> <s xml:id="echoid-s11850" xml:space="preserve"/> </p> <div xml:id="echoid-div520" type="float" level="2" n="6"> <note position="left" xlink:label="note-0558-05" xlink:href="note-0558-05a" xml:space="preserve">Commani-<lb/>cation.</note> </div> <pb o="13" file="0559" n="609" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> </div> <div xml:id="echoid-div522" type="section" level="1" n="139"> <head xml:id="echoid-head356" xml:space="preserve"><emph style="sc">Tenailles</emph>.</head> <p> <s xml:id="echoid-s11851" xml:space="preserve">Chaque tenaille ſera compoſée de deux faces qui auront vingt-<lb/> <anchor type="note" xlink:label="note-0559-01a" xlink:href="note-0559-01"/> huit toiſes de longueur chacune, & </s> <s xml:id="echoid-s11852" xml:space="preserve">ſera revêtuë devant & </s> <s xml:id="echoid-s11853" xml:space="preserve">derrie-<lb/>re. </s> <s xml:id="echoid-s11854" xml:space="preserve">Elle ſera coupée dans ſon angle rentrant par un paſſage pris <lb/>ſous ſon parapet, & </s> <s xml:id="echoid-s11855" xml:space="preserve">voûté de ſix pieds de largeur qui ſervira de <lb/>communication aux demi-lunes par le milieu du foſſé.</s> <s xml:id="echoid-s11856" xml:space="preserve"/> </p> <div xml:id="echoid-div522" type="float" level="2" n="1"> <note position="right" xlink:label="note-0559-01" xlink:href="note-0559-01a" xml:space="preserve">Tenailles.</note> </div> <p> <s xml:id="echoid-s11857" xml:space="preserve">Le revêtement des faces aura cinq pieds huit pouces d’épaiſſeur <lb/> <anchor type="note" xlink:label="note-0559-02a" xlink:href="note-0559-02"/> au deſſus des fondemens, & </s> <s xml:id="echoid-s11858" xml:space="preserve">ſera élevé de neuf pieds taluant d’un <lb/>ſur ſix par devant, à laquelle hauteur il ſera réduit à quatre pieds <lb/> <anchor type="note" xlink:label="note-0559-03a" xlink:href="note-0559-03"/> d’épais, puis ſera continué ſuivant le même talud juſqu’à trois pieds <lb/>plus haut ſur trois d’épaiſſeur ſeulement, réduit à deux & </s> <s xml:id="echoid-s11859" xml:space="preserve">demi <lb/>au ſommet, obſervant que ce ſommet ne ſoit pas plus élevé que <lb/>la ſurface du chemin couvert.</s> <s xml:id="echoid-s11860" xml:space="preserve"/> </p> <div xml:id="echoid-div523" type="float" level="2" n="2"> <note position="right" xlink:label="note-0559-02" xlink:href="note-0559-02a" xml:space="preserve">Revéte-<lb/>ment.</note> <note position="right" xlink:label="note-0559-03" xlink:href="note-0559-03a" xml:space="preserve">Executé à <lb/>Briſac.</note> </div> <p> <s xml:id="echoid-s11861" xml:space="preserve">A cette hauteur ſera faite une berme ſemblable à celle des con-<lb/> <anchor type="note" xlink:label="note-0559-04a" xlink:href="note-0559-04"/> tregardes, mais d’un pied ſix pouces de largeur ſeulement, & </s> <s xml:id="echoid-s11862" xml:space="preserve">ſans <lb/>haye vive; </s> <s xml:id="echoid-s11863" xml:space="preserve">ſur laquelle on élevera le parapet de la tenaille en ga-<lb/>zonnage ou placage, & </s> <s xml:id="echoid-s11864" xml:space="preserve">ce parapet aura huit pieds de hauteur par <lb/> <anchor type="note" xlink:label="note-0559-05a" xlink:href="note-0559-05"/> dehors, & </s> <s xml:id="echoid-s11865" xml:space="preserve">ſept & </s> <s xml:id="echoid-s11866" xml:space="preserve">demi par dedans, avec une banquette de deux <lb/>pieds de haut, du pied de laquelle le terre-plein de la tenaille ira <lb/>gagner le ſommet de la gorge.</s> <s xml:id="echoid-s11867" xml:space="preserve"/> </p> <div xml:id="echoid-div524" type="float" level="2" n="3"> <note position="right" xlink:label="note-0559-04" xlink:href="note-0559-04a" xml:space="preserve">Bermes & <lb/>parapet.</note> <note position="right" xlink:label="note-0559-05" xlink:href="note-0559-05a" xml:space="preserve">Executé à <lb/>Briſac.</note> </div> <p> <s xml:id="echoid-s11868" xml:space="preserve">Les gorges n’auront que quatre pieds dix pouces d’épaiſſeur par <lb/> <anchor type="note" xlink:label="note-0559-06a" xlink:href="note-0559-06"/> le bas, & </s> <s xml:id="echoid-s11869" xml:space="preserve">deux pieds & </s> <s xml:id="echoid-s11870" xml:space="preserve">demi par le haut, elles ſeront élevées de <lb/>quatorze pieds au deſſus des fondemens.</s> <s xml:id="echoid-s11871" xml:space="preserve"/> </p> <div xml:id="echoid-div525" type="float" level="2" n="4"> <note position="right" xlink:label="note-0559-06" xlink:href="note-0559-06a" xml:space="preserve">Gorges.</note> </div> <p> <s xml:id="echoid-s11872" xml:space="preserve">Les contreforts des faces auront cinq pieds de long, quatre de <lb/> <anchor type="note" xlink:label="note-0559-07a" xlink:href="note-0559-07"/> largeur à la racine, & </s> <s xml:id="echoid-s11873" xml:space="preserve">trois à la queuë, & </s> <s xml:id="echoid-s11874" xml:space="preserve">ne ſeront élevés que de <lb/>neuf pieds, ceux des gorges auront quatre pieds de longueur, <lb/>trois de largeur à la racine, deux à la queuë, & </s> <s xml:id="echoid-s11875" xml:space="preserve">ſeront de deux <lb/>pieds plus bas que le ſommet des gorges, ils ſeront tous eſpacés à <lb/>quinze pieds de diſtance les uns des autres de milieu en milieu.</s> <s xml:id="echoid-s11876" xml:space="preserve"/> </p> <div xml:id="echoid-div526" type="float" level="2" n="5"> <note position="right" xlink:label="note-0559-07" xlink:href="note-0559-07a" xml:space="preserve">Contre-<lb/>forts.</note> </div> <p> <s xml:id="echoid-s11877" xml:space="preserve">Pour communiquer au pont qui forme le paſſage de la contre-<lb/> <anchor type="note" xlink:label="note-0559-08a" xlink:href="note-0559-08"/> garde à la tenaille, il faudra pratiquer à l’extremité de ce pont <lb/>une rempe de ſix à ſept pieds de largeur dont les côtés ſeront re-<lb/>vêtus, & </s> <s xml:id="echoid-s11878" xml:space="preserve">former deux autres rempes joignant l’angle des gorges de <lb/>douze à quinze pieds de largeur, ſur trois toiſes cinq pieds de lon-<lb/>gueur, pour deſcendre dans le foſſé.</s> <s xml:id="echoid-s11879" xml:space="preserve"/> </p> <div xml:id="echoid-div527" type="float" level="2" n="6"> <note position="right" xlink:label="note-0559-08" xlink:href="note-0559-08a" xml:space="preserve">Rempes.</note> </div> </div> <div xml:id="echoid-div529" type="section" level="1" n="140"> <head xml:id="echoid-head357" xml:space="preserve"><emph style="sc">Demi</emph>-<emph style="sc">Lunes</emph>.</head> <p> <s xml:id="echoid-s11880" xml:space="preserve">Les faces des demi-lunes auront quarante huit toiſes de longueur <lb/> <anchor type="note" xlink:label="note-0559-09a" xlink:href="note-0559-09"/> chacune, & </s> <s xml:id="echoid-s11881" xml:space="preserve">les flancs ſept.</s> <s xml:id="echoid-s11882" xml:space="preserve"/> </p> <div xml:id="echoid-div529" type="float" level="2" n="1"> <note position="right" xlink:label="note-0559-09" xlink:href="note-0559-09a" xml:space="preserve">Demi-<lb/>lunss.</note> </div> <pb o="14" file="0560" n="610" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s11883" xml:space="preserve">Leur revêtement ſera de ſept pieds quatre pouces d’épaiſſeur au-<lb/> <anchor type="note" xlink:label="note-0560-01a" xlink:href="note-0560-01"/> deſſus des fondemens, de cinq à la hauteur de treize pieds, & </s> <s xml:id="echoid-s11884" xml:space="preserve">de <lb/>deux pieds ſix pouces au ſommet, faiſant en tout ſeize pieds d’é-<lb/>levation avec talud d’un ſur ſix. </s> <s xml:id="echoid-s11885" xml:space="preserve">Les gorges auront quinze pieds <lb/>de hauteur, & </s> <s xml:id="echoid-s11886" xml:space="preserve">tous les contreforts de ces pieces ſeront entiere-<lb/>ment conformes à ce qui a été dit pour ceux des contregardes.</s> <s xml:id="echoid-s11887" xml:space="preserve"/> </p> <div xml:id="echoid-div530" type="float" level="2" n="2"> <note position="left" xlink:label="note-0560-01" xlink:href="note-0560-01a" xml:space="preserve">Revéte-<lb/>ment des <lb/>demi-lunes, <lb/>gorges & <lb/>contreforts.</note> </div> <p> <s xml:id="echoid-s11888" xml:space="preserve">Il ſera fait, au niveau du ſommet du revêtement de ces faces & </s> <s xml:id="echoid-s11889" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0560-02a" xlink:href="note-0560-02"/> flancs, une berme de dix pieds de largeur garnie d’une haye vive, <lb/>ſur laquelle ſeront élevés les remparts & </s> <s xml:id="echoid-s11890" xml:space="preserve">parapets avec parement <lb/>exterieur de gazonnage taluant d’un tiers, ou avec placage ſeule-<lb/>ment taluant des deux tiers, ſur quinze pieds de hauteur à l’en-<lb/>droit des angles flanqués, & </s> <s xml:id="echoid-s11891" xml:space="preserve">quatorze pieds aux angles d’épaule, <lb/>y compris les trois pieds donnés pour l’affaiſſemenr des terres.</s> <s xml:id="echoid-s11892" xml:space="preserve"/> </p> <div xml:id="echoid-div531" type="float" level="2" n="3"> <note position="left" xlink:label="note-0560-02" xlink:href="note-0560-02a" xml:space="preserve">Bermes.</note> </div> <p> <s xml:id="echoid-s11893" xml:space="preserve">Les parapets & </s> <s xml:id="echoid-s11894" xml:space="preserve">banquettes auront d’ailleurs les mêmes dimen-<lb/> <anchor type="note" xlink:label="note-0560-03a" xlink:href="note-0560-03"/> ſions qu’aux contregardes.</s> <s xml:id="echoid-s11895" xml:space="preserve"/> </p> <div xml:id="echoid-div532" type="float" level="2" n="4"> <note position="left" xlink:label="note-0560-03" xlink:href="note-0560-03a" xml:space="preserve">Parapets & <lb/>banquettes.</note> </div> <p> <s xml:id="echoid-s11896" xml:space="preserve">Le terre-plein du rempart aura vingt pieds de largeur depuis le <lb/> <anchor type="note" xlink:label="note-0560-04a" xlink:href="note-0560-04"/> pied de la banquette juſqu’au bord du talud interieur, & </s> <s xml:id="echoid-s11897" xml:space="preserve">ſera <lb/>dreſſé en pente d’un pied & </s> <s xml:id="echoid-s11898" xml:space="preserve">demi du devant au derriere. </s> <s xml:id="echoid-s11899" xml:space="preserve">On y ob-<lb/>ſervera toutes les rempes & </s> <s xml:id="echoid-s11900" xml:space="preserve">eſcaliers qui ſont figurés dans le plan.</s> <s xml:id="echoid-s11901" xml:space="preserve"/> </p> <div xml:id="echoid-div533" type="float" level="2" n="5"> <note position="left" xlink:label="note-0560-04" xlink:href="note-0560-04a" xml:space="preserve">Rempart.</note> </div> <p> <s xml:id="echoid-s11902" xml:space="preserve">A chacune des quatre demi-lunes qui couvrirontles courtines des <lb/> <anchor type="note" xlink:label="note-0560-05a" xlink:href="note-0560-05"/> entrées principales de la Place, ſera faite une porte d’Architecture <lb/>de neuf pieds neuf pouces de largeur, & </s> <s xml:id="echoid-s11903" xml:space="preserve">treize de hauteur ſous <lb/>clef, avec les ornemens conformes aux deſſeins qui en ont été ré-<lb/>glés.</s> <s xml:id="echoid-s11904" xml:space="preserve"/> </p> <div xml:id="echoid-div534" type="float" level="2" n="6"> <note position="left" xlink:label="note-0560-05" xlink:href="note-0560-05a" xml:space="preserve">Portes d’ar-<lb/>chitecture.</note> </div> <p> <s xml:id="echoid-s11905" xml:space="preserve">Sera fait enſuite le revêtement du paſſage des entrées de ces de-<lb/> <anchor type="note" xlink:label="note-0560-06a" xlink:href="note-0560-06"/> mi-lunes, ſur toute la largeur de leur rempart & </s> <s xml:id="echoid-s11906" xml:space="preserve">parapet, & </s> <s xml:id="echoid-s11907" xml:space="preserve">les <lb/>murs de ces revêtemens ſeront élevés à plomb des deux côtés juſ-<lb/>qu’à la hauteur des parties qu’ils profileront ſur quatre pieds & </s> <s xml:id="echoid-s11908" xml:space="preserve"><lb/>demi d’épaiſſeur au deſſus des fondemens, avec retraite de trois <lb/>pouces de chaque côté. </s> <s xml:id="echoid-s11909" xml:space="preserve">Les contreforts auront cinq pieds de long, <lb/>quatre de large à la racine, trois à la queuë, & </s> <s xml:id="echoid-s11910" xml:space="preserve">ſeront eſpacés <lb/>comme ceux dont il a été parlé ci-deſſus. </s> <s xml:id="echoid-s11911" xml:space="preserve">Les paſſages ſeront ac-<lb/>compagnés de leurs ponts-levis, baſcules, & </s> <s xml:id="echoid-s11912" xml:space="preserve">deſcentes, ſuivant les <lb/>meſures de leurs plans & </s> <s xml:id="echoid-s11913" xml:space="preserve">profils particuliers.</s> <s xml:id="echoid-s11914" xml:space="preserve"/> </p> <div xml:id="echoid-div535" type="float" level="2" n="7"> <note position="left" xlink:label="note-0560-06" xlink:href="note-0560-06a" xml:space="preserve">Paſſage des <lb/>entrées.</note> </div> </div> <div xml:id="echoid-div537" type="section" level="1" n="141"> <head xml:id="echoid-head358" xml:space="preserve"><emph style="sc">Reduits dans les</emph> <emph style="sc">Demi</emph>-<emph style="sc">Lunes</emph>.</head> <p> <s xml:id="echoid-s11915" xml:space="preserve">Les faces des reduits auront dix-huit toiſes de longueur, les flancs <lb/> <anchor type="note" xlink:label="note-0560-07a" xlink:href="note-0560-07"/> trois toiſes, & </s> <s xml:id="echoid-s11916" xml:space="preserve">les retours des demi gorges ſix, le tout bien revêtu. <lb/></s> <s xml:id="echoid-s11917" xml:space="preserve">Le revêtement des faces & </s> <s xml:id="echoid-s11918" xml:space="preserve">flancs aura vingt-trois pieds de hauteur <lb/>depuis le deſſus des fondemens juſqu’au deſſus du cordon, où l’é- <pb o="15" file="0561" n="611" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> paiſſeur ſera réduite à cinq pieds, taluant par dehors d’un ſur ſix, <lb/>de ſorte qu’il aura neuf pieds d’épaiſſeur au-deſſus deſdits fonde-<lb/>mens, y compris les deux pouces de la ſaillie du ſoubaſſement.</s> <s xml:id="echoid-s11919" xml:space="preserve"/> </p> <div xml:id="echoid-div537" type="float" level="2" n="1"> <note position="left" xlink:label="note-0560-07" xlink:href="note-0560-07a" xml:space="preserve">Reduits. <lb/>Executé à <lb/>Briſac.</note> </div> <p> <s xml:id="echoid-s11920" xml:space="preserve">Les contreforts derriere cerevêtement ſeront élevés à même hau-<lb/> <anchor type="note" xlink:label="note-0561-01a" xlink:href="note-0561-01"/> teur que le deſſus du cordon, & </s> <s xml:id="echoid-s11921" xml:space="preserve">auront ſept pieds de longueur <lb/>chacun, quatre pieds de largeur à la racine, & </s> <s xml:id="echoid-s11922" xml:space="preserve">trois à la queuë.</s> <s xml:id="echoid-s11923" xml:space="preserve"/> </p> <div xml:id="echoid-div538" type="float" level="2" n="2"> <note position="right" xlink:label="note-0561-01" xlink:href="note-0561-01a" xml:space="preserve">Contreforts.</note> </div> <p> <s xml:id="echoid-s11924" xml:space="preserve">Au deſſus du cordon ſera élevé le revêtement du parapet en ma-<lb/> <anchor type="note" xlink:label="note-0561-02a" xlink:href="note-0561-02"/> çonnerie de brique ſur quatre pieds de hauteur & </s> <s xml:id="echoid-s11925" xml:space="preserve">trois d’épaiſ-<lb/>ſeur, & </s> <s xml:id="echoid-s11926" xml:space="preserve">le revêtement ſera remblayé de douze pieds de terre qui <lb/>formeront un parapet de quinze pieds d’épaiſſeur au ſommet, avec <lb/>plongée de deux pieds & </s> <s xml:id="echoid-s11927" xml:space="preserve">demi du dedans au dehors.</s> <s xml:id="echoid-s11928" xml:space="preserve"/> </p> <div xml:id="echoid-div539" type="float" level="2" n="3"> <note position="right" xlink:label="note-0561-02" xlink:href="note-0561-02a" xml:space="preserve">Parapet.</note> </div> <p> <s xml:id="echoid-s11929" xml:space="preserve">Les banquettes de ces pieces ſeront ſemblables à celles des de-<lb/> <anchor type="note" xlink:label="note-0561-03a" xlink:href="note-0561-03"/> mi-lunes; </s> <s xml:id="echoid-s11930" xml:space="preserve">les remparts auront quinze pieds de largeur avec pente <lb/>d’un pied & </s> <s xml:id="echoid-s11931" xml:space="preserve">demi du côté de la Place, & </s> <s xml:id="echoid-s11932" xml:space="preserve">dix pieds de talud inte-<lb/>rieur; </s> <s xml:id="echoid-s11933" xml:space="preserve">les gorges ſeront revêtues comme celles des demi-lunes, & </s> <s xml:id="echoid-s11934" xml:space="preserve"><lb/>auront les mêmes dimenſions.</s> <s xml:id="echoid-s11935" xml:space="preserve"/> </p> <div xml:id="echoid-div540" type="float" level="2" n="4"> <note position="right" xlink:label="note-0561-03" xlink:href="note-0561-03a" xml:space="preserve">Banquet-<lb/>tes, rem-<lb/>parts & <lb/>gorges.</note> </div> <p> <s xml:id="echoid-s11936" xml:space="preserve">Quatre de ces réduits ſeront percés d’un paſſage de ſix pieds de <lb/> <anchor type="note" xlink:label="note-0561-04a" xlink:href="note-0561-04"/> largeur, revêtu & </s> <s xml:id="echoid-s11937" xml:space="preserve">voûté pour ſervir de communication aux de-<lb/>mi-lunes. </s> <s xml:id="echoid-s11938" xml:space="preserve">Le revêtement de ce paſſage ſera élevé à plomb, & </s> <s xml:id="echoid-s11939" xml:space="preserve">aura <lb/>quatre pieds & </s> <s xml:id="echoid-s11940" xml:space="preserve">demi d’épaiſſeur au-deſſus de ſes fondemens, ſur au-<lb/>tant de hauteur, où la maçonnerie ſera miſe de niveau pour com-<lb/>mencer la naiſſance des voûtes qui ſeront conſtruites à plein cein-<lb/>tre. </s> <s xml:id="echoid-s11941" xml:space="preserve">Les entrées & </s> <s xml:id="echoid-s11942" xml:space="preserve">ſorties du paſſage auront quatre pieds & </s> <s xml:id="echoid-s11943" xml:space="preserve">demi <lb/>de largeur entre les pieds droits qui auront chacun double feüillu-<lb/>re, ainſi que tous ceux des autres poternes, pour y poſer des por-<lb/>tes de quatre pouces d’épaiſſeur. </s> <s xml:id="echoid-s11944" xml:space="preserve">On obſervera dans ces réduits, <lb/>comme aux demi-lunes, les rempes & </s> <s xml:id="echoid-s11945" xml:space="preserve">eſcaliers néceſſaires pour éta-<lb/>blir les communications, & </s> <s xml:id="echoid-s11946" xml:space="preserve">on y pratiquera de plus une deſcente <lb/>au foſſé de trois pieds de largeur dans œuvre, ſur vingt de longueur, <lb/>joignant le mur de la gorge qui ſera percé d’un paſſage de trois <lb/>pieds de largeur pour communiquer au foſſé; </s> <s xml:id="echoid-s11947" xml:space="preserve">le mur, qui ſoutien-<lb/>dra les marches du côté des terres, aura auſſi trois pieds d’épaiſ-<lb/>ſeur, & </s> <s xml:id="echoid-s11948" xml:space="preserve">le deſſus de cette deſcente ſera recouvert par une trape <lb/>garnie de ferrures & </s> <s xml:id="echoid-s11949" xml:space="preserve">ſerrures néceſſaires, pour empêcher qu’on n’y <lb/>entre qu’en cas de beſoin. </s> <s xml:id="echoid-s11950" xml:space="preserve">On formera auſſi quatre grands paſſa-<lb/>ges pour les voitures, ſemblables à ceux des demi-lunes, aux qua-<lb/>tre réduits qui ſe trouveront ſur les entrées principales, & </s> <s xml:id="echoid-s11951" xml:space="preserve">ſur <lb/>chacun deſdits paſſages ſera érigée une porte d’architecture confor-<lb/>me à ſon deſſein particulier, de même qu’un petit corps de <lb/>garde.</s> <s xml:id="echoid-s11952" xml:space="preserve"/> </p> <div xml:id="echoid-div541" type="float" level="2" n="5"> <note position="right" xlink:label="note-0561-04" xlink:href="note-0561-04a" xml:space="preserve">Commu-<lb/>nication.</note> </div> <pb o="16" file="0562" n="612" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div543" type="section" level="1" n="142"> <head xml:id="echoid-head359" xml:space="preserve"><emph style="sc">Ouvrage a corne</emph>.</head> <p> <s xml:id="echoid-s11953" xml:space="preserve">Les branches de l’ouvrage à corne auront cent vingt toiſes de <lb/> <anchor type="note" xlink:label="note-0562-01a" xlink:href="note-0562-01"/> longueur chacune, ſon poligone cent cinquante, ſes faces qua-<lb/>rante, ſes flancs quinze, & </s> <s xml:id="echoid-s11954" xml:space="preserve">ſa courtine ſoixante-neuf.</s> <s xml:id="echoid-s11955" xml:space="preserve"/> </p> <div xml:id="echoid-div543" type="float" level="2" n="1"> <note position="left" xlink:label="note-0562-01" xlink:href="note-0562-01a" xml:space="preserve">Ouvrage à <lb/>corne.</note> </div> <p> <s xml:id="echoid-s11956" xml:space="preserve">Tous les revêtemens de cet ouvrage, auſſi-bien que les remparts, <lb/>banquettes, & </s> <s xml:id="echoid-s11957" xml:space="preserve">parapet, ſeront conformes en toutes choſes à ceux <lb/>des demi-lunes, avec cette ſeule difference que la tête des branches <lb/>ſera plus élevée de quatre pieds que leurs extrémités, dont la hau-<lb/>teur ne ſurpaſſera pas celle du chemin couvert, obſervant encore <lb/>de ne terraſſer les revêtemens que juſqu’à dix-huit toiſes près du-<lb/>dit chemin couvert, & </s> <s xml:id="echoid-s11958" xml:space="preserve">de diminuer la largeur du rempart depuis <lb/>le canal de l’Hôpital qui y ſera renfermé, juſqu’à cette diſtance, <lb/>de maniere que le tout ſe réduiſe dans le cours des dix-huit toiſes <lb/>ci-deſſus marquées aux banquettes pures & </s> <s xml:id="echoid-s11959" xml:space="preserve">ſimples.</s> <s xml:id="echoid-s11960" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11961" xml:space="preserve">On obſervera au ſurplus de faire des batteries à barbette ſur les <lb/> <anchor type="note" xlink:label="note-0562-02a" xlink:href="note-0562-02"/> pointes des baſtions & </s> <s xml:id="echoid-s11962" xml:space="preserve">demi-lunes de l’ouvrage à corne, qui ſeront <lb/>retournées de ſept à huit toiſes de part & </s> <s xml:id="echoid-s11963" xml:space="preserve">d’autre des angles flan-<lb/>qués.</s> <s xml:id="echoid-s11964" xml:space="preserve"/> </p> <div xml:id="echoid-div544" type="float" level="2" n="2"> <note position="left" xlink:label="note-0562-02" xlink:href="note-0562-02a" xml:space="preserve">Barbettes.</note> </div> <p> <s xml:id="echoid-s11965" xml:space="preserve">Vis-à-vis le rempart ſera fait le revêtement en parement de pier-<lb/> <anchor type="note" xlink:label="note-0562-03a" xlink:href="note-0562-03"/> re de taille du canal qui traverſe les deux longs côtés, & </s> <s xml:id="echoid-s11966" xml:space="preserve">cela ſur <lb/>ſept pieds & </s> <s xml:id="echoid-s11967" xml:space="preserve">demi d’épaiſſeur, non compris ſix pouces pour les re-<lb/>traites des fondemens. </s> <s xml:id="echoid-s11968" xml:space="preserve">On fera auſſi des arcades de pierre de taille <lb/>aux entrées & </s> <s xml:id="echoid-s11969" xml:space="preserve">ſorties dudit canal, & </s> <s xml:id="echoid-s11970" xml:space="preserve">on y pratiquera les couliſſes <lb/>néceſſaires pour leurs fermetures: </s> <s xml:id="echoid-s11971" xml:space="preserve">Le reſte de ce paſſage, qui ſera <lb/>compris entre les arcades & </s> <s xml:id="echoid-s11972" xml:space="preserve">le talud des banquettes, ſera voûté <lb/>de briques ſur trois pieds d’épaiſſeur, & </s> <s xml:id="echoid-s11973" xml:space="preserve">recouvert d’une chape <lb/>de ciment.</s> <s xml:id="echoid-s11974" xml:space="preserve"><anchor type="note" xlink:href="" symbol="*"/> <anchor type="note" xlink:label="note-0562-04a" xlink:href="note-0562-04"/> Livre.</s> </p> </div> <div xml:id="echoid-div546" type="section" level="1" n="143"> <head xml:id="echoid-head360" xml:space="preserve"><emph style="sc">Fossez</emph>.</head> <p><s xml:id="echoid-s11975" xml:space="preserve"> <anchor type="note" xlink:label="note-0562-05a" xlink:href="note-0562-05"/> meſurées à l’aplomb du cordon, ou du trait principal des ouvra- ges & du ſommet de la contreſcarpe. Sçavoir aux angles flan- qués des Tours baſtionnées, ſept toiſes; vis-à-vis le milieu des courtines, ſeize toiſes trois pieds; entre les contregardes & les te- nailles, cinq toiſes; vis-à-vis le milieu des faces des contregardes, quinze à ſeize ſelon le beſoin qu’on aura de terre; vis-à-vis les faces des réduits, ſix toiſes; vis-à-vis celles des demi-lunes, dix; vis-à-vis les branches & demi-baſtions de l’ouvrage à corne, dix; vis-à-vis la demi-lune de cet ouvrage à corne, ſept.</s></p> <div xml:id="echoid-div546" type="float" level="2" n="1"> <note position="left" xlink:label="note-0562-03" xlink:href="note-0562-03a" xml:space="preserve">Revéte-<lb/>ment du <lb/>paſſage du <lb/>canal.</note> <note position="left" xlink:label="note-0562-05" xlink:href="note-0562-05a" xml:space="preserve">Largeur <lb/>des Foſſez.</note> </div> <pb o="17" file="0563" n="613" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s11976" xml:space="preserve">Tous ces foſſez en general ſeront approfondis de quatorze à <lb/> <anchor type="note" xlink:label="note-0563-01a" xlink:href="note-0563-01"/> quinze pieds au-deſſus du rez-de-chauſſée de la Place, & </s> <s xml:id="echoid-s11977" xml:space="preserve">revêtus <lb/>d’un mur de pareille hauteur taluant de ſon ſixiéme par dehors, <lb/>& </s> <s xml:id="echoid-s11978" xml:space="preserve">réduits à trois pieds d’épaiſſeur au ſommet.</s> <s xml:id="echoid-s11979" xml:space="preserve"/> </p> <div xml:id="echoid-div547" type="float" level="2" n="2"> <note position="right" xlink:label="note-0563-01" xlink:href="note-0563-01a" xml:space="preserve">Profondeur <lb/>& revête-<lb/>ment des <lb/>foſſez.</note> </div> <p> <s xml:id="echoid-s11980" xml:space="preserve">Il ſera fait en même tems des contreforts derriere le mur à quin-<lb/> <anchor type="note" xlink:label="note-0563-02a" xlink:href="note-0563-02"/> ze pieds de diſtance les uns des autres de milieu en milieu, dont <lb/>la longueur ſera de quatre pieds, la largeur de quatre & </s> <s xml:id="echoid-s11981" xml:space="preserve">demi à <lb/>la racine, & </s> <s xml:id="echoid-s11982" xml:space="preserve">de trois à la queuë, & </s> <s xml:id="echoid-s11983" xml:space="preserve">la hauteur un pied plus bas <lb/>que le ſommet de revêtement.</s> <s xml:id="echoid-s11984" xml:space="preserve"/> </p> <div xml:id="echoid-div548" type="float" level="2" n="3"> <note position="right" xlink:label="note-0563-02" xlink:href="note-0563-02a" xml:space="preserve">Contreforts.</note> </div> <p> <s xml:id="echoid-s11985" xml:space="preserve">En faiſant la diſtribution de ces contreforts, on aura ſoin d’en <lb/>placer deux à l’endroit de toutes les traverſes du chemin couvert, <lb/>afin que les profils des traverſes qui ſeront auſſi revêtus, en ſoient <lb/>mieux ſoutenus & </s> <s xml:id="echoid-s11986" xml:space="preserve">plus ſolidement établis. </s> <s xml:id="echoid-s11987" xml:space="preserve">Ces contreforts doivent <lb/>avoir un pied de largeur & </s> <s xml:id="echoid-s11988" xml:space="preserve">ſix pouces d’épaiſſeur en tous ſens <lb/>plus que les précedens.</s> <s xml:id="echoid-s11989" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s11990" xml:space="preserve">Quant à l’excavation des grands foſſez de la Place, il faut avoir <lb/>attention de donner près de vingt pieds de profondeur vis-à-<lb/>vis les angles flanqués des contregardes, & </s> <s xml:id="echoid-s11991" xml:space="preserve">de remonter inſen-<lb/>ſiblement vers le milieu des tenailles & </s> <s xml:id="echoid-s11992" xml:space="preserve">courtines. </s> <s xml:id="echoid-s11993" xml:space="preserve">On obſervera <lb/>encore d’approfondir le petit foſſé qui ſera entre le derriere des <lb/>tenailles & </s> <s xml:id="echoid-s11994" xml:space="preserve">les petits flancs des courtines, de trois ou quatre pieds <lb/>plus que celui de la Place, afin qu’il puiſſe y avoir de l’eau en tout <lb/>tems. </s> <s xml:id="echoid-s11995" xml:space="preserve">Pareille attention ſera faite le long des flancs des contregar-<lb/>des, & </s> <s xml:id="echoid-s11996" xml:space="preserve">le revêtement de ces parties qui ſera fondé plus bas que <lb/>les autres à proportion.</s> <s xml:id="echoid-s11997" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div550" type="section" level="1" n="144"> <head xml:id="echoid-head361" xml:space="preserve"><emph style="sc">Chemin</emph> <emph style="sc">Couvert</emph>.</head> <p> <s xml:id="echoid-s11998" xml:space="preserve">Tous les chemins couverts ſeront tracés parallelement aux foſ-<lb/> <anchor type="note" xlink:label="note-0563-03a" xlink:href="note-0563-03"/> ſez de la Place ſur cinq toiſes de largeur, à compter depuis le pied <lb/>de la banquette juſqu’au bord de ces mêmes foſſez, & </s> <s xml:id="echoid-s11999" xml:space="preserve">ſeront dreſ-<lb/>ſés en pente d’un pied & </s> <s xml:id="echoid-s12000" xml:space="preserve">demi du côté des ouvrages: </s> <s xml:id="echoid-s12001" xml:space="preserve">on y obſer-<lb/>vera tous les petits retours, redens, & </s> <s xml:id="echoid-s12002" xml:space="preserve">traverſes qui ſont figurés ſur <lb/>le plan.</s> <s xml:id="echoid-s12003" xml:space="preserve"/> </p> <div xml:id="echoid-div550" type="float" level="2" n="1"> <note position="right" xlink:label="note-0563-03" xlink:href="note-0563-03a" xml:space="preserve">Chemin <lb/>couvert.</note> </div> <p> <s xml:id="echoid-s12004" xml:space="preserve">Les Places d’armes auront dix toiſes & </s> <s xml:id="echoid-s12005" xml:space="preserve">demie de gorge, & </s> <s xml:id="echoid-s12006" xml:space="preserve">trei-<lb/> <anchor type="note" xlink:label="note-0563-04a" xlink:href="note-0563-04"/> ze de face.</s> <s xml:id="echoid-s12007" xml:space="preserve"/> </p> <div xml:id="echoid-div551" type="float" level="2" n="2"> <note position="right" xlink:label="note-0563-04" xlink:href="note-0563-04a" xml:space="preserve">Places d’ar-<lb/>mes.</note> </div> <p> <s xml:id="echoid-s12008" xml:space="preserve">Les traverſes dix-huit pieds d’épaiſſeur meſurés au ſommet, & </s> <s xml:id="echoid-s12009" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0563-05a" xlink:href="note-0563-05"/> les banquettes cinq pieds de largeur, un pied & </s> <s xml:id="echoid-s12010" xml:space="preserve">demi de hauteur, <lb/>& </s> <s xml:id="echoid-s12011" xml:space="preserve">trois pieds de talud.</s> <s xml:id="echoid-s12012" xml:space="preserve"/> </p> <div xml:id="echoid-div552" type="float" level="2" n="3"> <note position="right" xlink:label="note-0563-05" xlink:href="note-0563-05a" xml:space="preserve">Traverſes.</note> </div> <p> <s xml:id="echoid-s12013" xml:space="preserve">Le parapet ſera élevé de quatre pieds & </s> <s xml:id="echoid-s12014" xml:space="preserve">demiau deſſus de la ban-<lb/> <anchor type="note" xlink:label="note-0563-06a" xlink:href="note-0563-06"/> quette, & </s> <s xml:id="echoid-s12015" xml:space="preserve">revêtu de deux pieds & </s> <s xml:id="echoid-s12016" xml:space="preserve">demi d’épaiſſeur avec talud d’un <pb o="18" file="0564" n="614" rhead="LA SCIENCE DES INGENIEURS,"/> ſixiéme par devant juſqu’à un pied {1/2} près du ſommet, qui ſera en-<lb/>ſuite achevé en gazonnage, & </s> <s xml:id="echoid-s12017" xml:space="preserve">bordé ainſi que les traverſes d’un <lb/>rang de paliſſades plantées & </s> <s xml:id="echoid-s12018" xml:space="preserve">conditionnées, comme il eſt dit en <lb/>ſon lieu.</s> <s xml:id="echoid-s12019" xml:space="preserve"/> </p> <div xml:id="echoid-div553" type="float" level="2" n="4"> <note position="right" xlink:label="note-0563-06" xlink:href="note-0563-06a" xml:space="preserve">Parapet.</note> </div> <p> <s xml:id="echoid-s12020" xml:space="preserve">Le Parapet ſera coupé en pluſieurs endroits le long des branches <lb/> <anchor type="note" xlink:label="note-0564-01a" xlink:href="note-0564-01"/> du chemin couvert, & </s> <s xml:id="echoid-s12021" xml:space="preserve">dans les faces des Places d’armes, par <lb/>des paſſages de ſortie de dix à douze pieds d’ouverture, dont la <lb/>rempe ſe prendra dans le glacis, & </s> <s xml:id="echoid-s12022" xml:space="preserve">s’étendra à deux ou trois toi-<lb/>ſes. </s> <s xml:id="echoid-s12023" xml:space="preserve">Ces paſſages, de même que ceux qui aboutiſſent aux entrées <lb/>principales de la Place, ſeront revêtus de maçonnerie, & </s> <s xml:id="echoid-s12024" xml:space="preserve">fermés <lb/>par des barrieres de force ſuffiſante à deux venteaux; </s> <s xml:id="echoid-s12025" xml:space="preserve">on poſera <lb/>auſſi des barrieres à un ſeul ventail au paſſage de chaque traverſe.</s> <s xml:id="echoid-s12026" xml:space="preserve"/> </p> <div xml:id="echoid-div554" type="float" level="2" n="5"> <note position="left" xlink:label="note-0564-01" xlink:href="note-0564-01a" xml:space="preserve">Paſſage de <lb/>ſortie.</note> </div> </div> <div xml:id="echoid-div556" type="section" level="1" n="145"> <head xml:id="echoid-head362" xml:space="preserve"><emph style="sc">Glacis</emph>.</head> <p> <s xml:id="echoid-s12027" xml:space="preserve">Le glacis ſera bien dreſſé & </s> <s xml:id="echoid-s12028" xml:space="preserve">parfaitement ſoumis à la découverte <lb/> <anchor type="note" xlink:label="note-0564-02a" xlink:href="note-0564-02"/> des contregardes & </s> <s xml:id="echoid-s12029" xml:space="preserve">demi-lunes, deſquelles il ſera défendu; </s> <s xml:id="echoid-s12030" xml:space="preserve">il ſera <lb/>étendu de vingt-cinq ou trente toiſes au moins, & </s> <s xml:id="echoid-s12031" xml:space="preserve">ſa pente ſera re-<lb/>glée ſuivant le ſommet du parapet du chemin couvert, fichant, à un <lb/>pied au-deſſous du ſommet des parapets, des demi-lunes & </s> <s xml:id="echoid-s12032" xml:space="preserve">contre-<lb/>gardes.</s> <s xml:id="echoid-s12033" xml:space="preserve"/> </p> <div xml:id="echoid-div556" type="float" level="2" n="1"> <note position="left" xlink:label="note-0564-02" xlink:href="note-0564-02a" xml:space="preserve">Glacis.</note> </div> </div> <div xml:id="echoid-div558" type="section" level="1" n="146"> <head xml:id="echoid-head363" xml:space="preserve"><emph style="sc">Ponts</emph>.</head> <p> <s xml:id="echoid-s12034" xml:space="preserve">Il ſe fera des ponts de charpente de quinze pieds dans œuvre, <lb/> <anchor type="note" xlink:label="note-0564-03a" xlink:href="note-0564-03"/> ſur les travers tant du grand foſſé, que de ceux des réduits, de-<lb/>mi-lunes & </s> <s xml:id="echoid-s12035" xml:space="preserve">tenailles des quatre entrées principales de la Place, <lb/>dont les fermes ſeront eſpacées à douze pieds les unes des autres <lb/>de milieu en milieu, & </s> <s xml:id="echoid-s12036" xml:space="preserve">poſées ſur une pile de maçonnerie de pier-<lb/>re de taille d’un pied & </s> <s xml:id="echoid-s12037" xml:space="preserve">demi de largeur, & </s> <s xml:id="echoid-s12038" xml:space="preserve">d’un pied de hauteur <lb/>au deſſus du fond du foſſé.</s> <s xml:id="echoid-s12039" xml:space="preserve"/> </p> <div xml:id="echoid-div558" type="float" level="2" n="1"> <note position="left" xlink:label="note-0564-03" xlink:href="note-0564-03a" xml:space="preserve">Ponts-dor-<lb/>mans.</note> </div> <p> <s xml:id="echoid-s12040" xml:space="preserve">Il ſera fait auſſi de petits ponts de communication des Tours <lb/>baſtionnées aux contregardes, & </s> <s xml:id="echoid-s12041" xml:space="preserve">des contregardes aux tenailles, <lb/>qui auront chacun cinq pieds de largeur dans œuvre, & </s> <s xml:id="echoid-s12042" xml:space="preserve">ſeront <lb/>conſtruits avec les mêmes précautions que les précédens.</s> <s xml:id="echoid-s12043" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12044" xml:space="preserve">Tous les ponts-levis des entrées principales joignant les courtines <lb/>& </s> <s xml:id="echoid-s12045" xml:space="preserve">demi-lunes ſeront à baſcules, & </s> <s xml:id="echoid-s12046" xml:space="preserve">les autres à fleches; </s> <s xml:id="echoid-s12047" xml:space="preserve">on poſera <lb/>de grandes barrieres à doubles ventaux, tant aux tenailles qu’à la <lb/>tête des ponts-dormans, & </s> <s xml:id="echoid-s12048" xml:space="preserve">à l’entrée du chemin couvert; </s> <s xml:id="echoid-s12049" xml:space="preserve">de ſorte <lb/>qu’il y aura quatre ponts-levis à chaque entrée principale, ſçavoir <lb/>un à la grande porte du corps de la Place, un autre à la tenaille, <lb/>un au réduit, & </s> <s xml:id="echoid-s12050" xml:space="preserve">un à la demi-lune; </s> <s xml:id="echoid-s12051" xml:space="preserve">& </s> <s xml:id="echoid-s12052" xml:space="preserve">trois barrieres, ſçavoir une <pb o="19" file="0565" n="615" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> à la tête du grand pont, une à la tête de celui de la demi-lune, <lb/>& </s> <s xml:id="echoid-s12053" xml:space="preserve">la troiſiéme au chemin couvert; </s> <s xml:id="echoid-s12054" xml:space="preserve">le tout conſtruit & </s> <s xml:id="echoid-s12055" xml:space="preserve">executé <lb/>ſuivant les deſſeins qui en ont été reglés. </s> <s xml:id="echoid-s12056" xml:space="preserve">On fera auſſi les petits <lb/>ponts-levis néceſſaires aux ponts de communication des contre-<lb/>gardes aux tenailles.</s> <s xml:id="echoid-s12057" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div560" type="section" level="1" n="147"> <head xml:id="echoid-head364" xml:space="preserve"><emph style="sc">Puits et</emph> <emph style="sc">Pave’ de la</emph> <emph style="sc">Place</emph>.</head> <p> <s xml:id="echoid-s12058" xml:space="preserve">Il ſera fait quatre Puits ſur la grande Place, de cinq pieds de <lb/>diametre chacun, & </s> <s xml:id="echoid-s12059" xml:space="preserve">ſur toute l’étenduë de la Place ſera fait un <lb/>Pavé de cailloux avec toutes les pentes & </s> <s xml:id="echoid-s12060" xml:space="preserve">ruiſſeaux néceſſaires.</s> <s xml:id="echoid-s12061" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div561" type="section" level="1" n="148"> <head xml:id="echoid-head365" xml:space="preserve"><emph style="sc">Batimens principaux</emph>.</head> <p> <s xml:id="echoid-s12062" xml:space="preserve">Il ſera conſtruit dans l’enceinte de ces ouvrages, ſçavoir au pied <lb/>du rempart de chaque front, un corps de Cazernes avec un pa-<lb/>villon pour les Officiers à chacune de ſes extremités, une Egliſe, <lb/>une Maiſon de Ville, un Arſenal & </s> <s xml:id="echoid-s12063" xml:space="preserve">une Munition, des Magazins <lb/>& </s> <s xml:id="echoid-s12064" xml:space="preserve">Hangards tant pour les vivres que pour l’artillerie, un Logement <lb/>pour le Gouverneur, un pour le Lieutenant de Roi & </s> <s xml:id="echoid-s12065" xml:space="preserve">Major, un <lb/>pour les Aides Majors & </s> <s xml:id="echoid-s12066" xml:space="preserve">Capitaines des Portes, un pour l’Inten-<lb/>dant & </s> <s xml:id="echoid-s12067" xml:space="preserve">le Commiſſaire, & </s> <s xml:id="echoid-s12068" xml:space="preserve">un pour les Ingenieurs. </s> <s xml:id="echoid-s12069" xml:space="preserve">Tous ces bâti-<lb/>mens, auſſi-bien que les Corps de gardes & </s> <s xml:id="echoid-s12070" xml:space="preserve">latrines, ſeront conſtruits <lb/>chacun ſelon leurs deſſeins & </s> <s xml:id="echoid-s12071" xml:space="preserve">devis particuliers. </s> <s xml:id="echoid-s12072" xml:space="preserve">A l’égard de l’Hô-<lb/>pital, il convient qu’il ſoit placé dans l’interieur de l’ouvrage à <lb/>corne.</s> <s xml:id="echoid-s12073" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div562" type="section" level="1" n="149"> <head xml:id="echoid-head366" xml:space="preserve">III. <lb/>QUALITE’S ET FAÇONS DES MATERIAUX <lb/>qui ſeront employés aux ſuſdits Ouvrages. <lb/><emph style="sc">Chaux</emph>, <emph style="sc">Sable</emph>, <emph style="sc">Mortier, et</emph> <emph style="sc">Ciment</emph>.</head> <p> <s xml:id="echoid-s12074" xml:space="preserve">LA chaux, qui ſera employée à la conſtruction de la maçonne-<lb/> <anchor type="note" xlink:label="note-0565-01a" xlink:href="note-0565-01"/> rie, ſera priſe à .</s> <s xml:id="echoid-s12075" xml:space="preserve">..</s> <s xml:id="echoid-s12076" xml:space="preserve">. & </s> <s xml:id="echoid-s12077" xml:space="preserve">autres lieux où elle ſe trouvera de <lb/>même qualité. </s> <s xml:id="echoid-s12078" xml:space="preserve">On obſervera, 10. </s> <s xml:id="echoid-s12079" xml:space="preserve">qu’elle ſoit bien cuite, ſans biſ-<lb/>cuit, non éventée; </s> <s xml:id="echoid-s12080" xml:space="preserve">20. </s> <s xml:id="echoid-s12081" xml:space="preserve">qu’elle ſoit éteinte un jour ou deux au moins <lb/>avant que de l’employer; </s> <s xml:id="echoid-s12082" xml:space="preserve">& </s> <s xml:id="echoid-s12083" xml:space="preserve">on aura ſoin d’en faire ôter tous les <lb/>biſcuits & </s> <s xml:id="echoid-s12084" xml:space="preserve">durillons qui pourront s’y rencontrer.</s> <s xml:id="echoid-s12085" xml:space="preserve"/> </p> <div xml:id="echoid-div562" type="float" level="2" n="1"> <note position="right" xlink:label="note-0565-01" xlink:href="note-0565-01a" xml:space="preserve">Chaux.</note> </div> <p> <s xml:id="echoid-s12086" xml:space="preserve">Le ſable ſera de deux eſpeces, l’un gros, & </s> <s xml:id="echoid-s12087" xml:space="preserve">l’autre fin, tous deux <lb/> <anchor type="note" xlink:label="note-0565-02a" xlink:href="note-0565-02"/> tirés de la riviere de .</s> <s xml:id="echoid-s12088" xml:space="preserve">..</s> <s xml:id="echoid-s12089" xml:space="preserve">. du foſſé de la Place, ou de ſes environs: <lb/></s> <s xml:id="echoid-s12090" xml:space="preserve">le gros ſera employé à faire le mortier de la maçonnerie de moë- <pb o="20" file="0566" n="616" rhead="LA SCIENCE DES INGENIEURS,"/> lon, & </s> <s xml:id="echoid-s12091" xml:space="preserve">le fin à faire celui de la maçonnerie de brique, des pare-<lb/>mens, & </s> <s xml:id="echoid-s12092" xml:space="preserve">des pierres de taille; </s> <s xml:id="echoid-s12093" xml:space="preserve">on aura ſoin qu’il ſoit ſec, criant à <lb/>la main, bien lavé, & </s> <s xml:id="echoid-s12094" xml:space="preserve">non gras ni terreux.</s> <s xml:id="echoid-s12095" xml:space="preserve"/> </p> <div xml:id="echoid-div563" type="float" level="2" n="2"> <note position="right" xlink:label="note-0565-02" xlink:href="note-0565-02a" xml:space="preserve">Sable.</note> </div> <p> <s xml:id="echoid-s12096" xml:space="preserve">Le mortier ſera compoſé d’un tiers de chaux meſurée vive, & </s> <s xml:id="echoid-s12097" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0566-01a" xlink:href="note-0566-01"/> de deux tiers de ſable, mêlé, broyé, & </s> <s xml:id="echoid-s12098" xml:space="preserve">incorporé avec la chaux <lb/>tant & </s> <s xml:id="echoid-s12099" xml:space="preserve">ſi long-tems, que les eſpeces ſoient totalement confonduës <lb/>l’une dans l’autre, juſqu’à n’y plus reconnoître de difference. </s> <s xml:id="echoid-s12100" xml:space="preserve">On <lb/>n’y employera que l’eau ſimplement néceſſaire à leur mêlange, & </s> <s xml:id="echoid-s12101" xml:space="preserve"><lb/>cela une ſeule fois, & </s> <s xml:id="echoid-s12102" xml:space="preserve">non plus.</s> <s xml:id="echoid-s12103" xml:space="preserve"/> </p> <div xml:id="echoid-div564" type="float" level="2" n="3"> <note position="left" xlink:label="note-0566-01" xlink:href="note-0566-01a" xml:space="preserve">Mortier.</note> </div> <p> <s xml:id="echoid-s12104" xml:space="preserve">Si on n’employe la chaux qu’après avoir été éteinte, comme il <lb/>eſt d’uſage en pluſieurs endroits, il faudra en augmenter la doſe à <lb/>proportion de ſa qualité, ce qui va quelquefois à la moitié.</s> <s xml:id="echoid-s12105" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12106" xml:space="preserve">Le ciment ſera fait de vieux tuileaux bien cuits & </s> <s xml:id="echoid-s12107" xml:space="preserve">réduits en <lb/> <anchor type="note" xlink:label="note-0566-02a" xlink:href="note-0566-02"/> farine par la meule, puis paſſés au tamis du Boulanger, ou au <lb/>bluteau. </s> <s xml:id="echoid-s12108" xml:space="preserve">Il ſera compoſé des deux tiers de cette farine, & </s> <s xml:id="echoid-s12109" xml:space="preserve">d’un tiers <lb/>de chaux meſurée vive; </s> <s xml:id="echoid-s12110" xml:space="preserve">le tout bien battu & </s> <s xml:id="echoid-s12111" xml:space="preserve">corroyé enſemble, & </s> <s xml:id="echoid-s12112" xml:space="preserve"><lb/>démêlé pendant un long eſpace de tems & </s> <s xml:id="echoid-s12113" xml:space="preserve">à pluſieurs repriſes, <lb/>dans un petit baſſin de planches, quarré, fait exprès; </s> <s xml:id="echoid-s12114" xml:space="preserve">obſervant de <lb/>n’y mettre de l’eau qu’une ſeule fois, & </s> <s xml:id="echoid-s12115" xml:space="preserve">de l’employer, autant que <lb/>faire ſe pourra, tout chaud & </s> <s xml:id="echoid-s12116" xml:space="preserve">frais battu, de même que de ne le <lb/>doſer que par rapport à la force de la chaux, & </s> <s xml:id="echoid-s12117" xml:space="preserve">à la qualité du <lb/>ciment.</s> <s xml:id="echoid-s12118" xml:space="preserve"/> </p> <div xml:id="echoid-div565" type="float" level="2" n="4"> <note position="left" xlink:label="note-0566-02" xlink:href="note-0566-02a" xml:space="preserve">Ciment.</note> </div> </div> <div xml:id="echoid-div567" type="section" level="1" n="150"> <head xml:id="echoid-head367" xml:space="preserve"><emph style="sc">Pierre de taille</emph>, <emph style="sc">Moelon, et</emph> <emph style="sc">Brique</emph>.</head> <p> <s xml:id="echoid-s12119" xml:space="preserve">Toute la pierre de taille, tant des angles ſaillans des ouvrages, <lb/> <anchor type="note" xlink:label="note-0566-03a" xlink:href="note-0566-03"/> que des ſoubaſſemens, cordons, & </s> <s xml:id="echoid-s12120" xml:space="preserve">autres parties où il en ſera be-<lb/>ſoin, ſera tirée des carrieres de .</s> <s xml:id="echoid-s12121" xml:space="preserve">..</s> <s xml:id="echoid-s12122" xml:space="preserve">. ou autres lieux qui en pour-<lb/>ront fournir de pareille qualité, c’eſt-à-dire, qui ſoit pleine, du-<lb/>re, non ſujette à la lune ni à la gelée; </s> <s xml:id="echoid-s12123" xml:space="preserve">obſervant de n’employer <lb/>que celle qui ſera bien ébouſinée, ſans fil, ni moye, qui la traver-<lb/>ſe ou qui paroiſſe, à ſix pouces près des paremens.</s> <s xml:id="echoid-s12124" xml:space="preserve"/> </p> <div xml:id="echoid-div567" type="float" level="2" n="1"> <note position="left" xlink:label="note-0566-03" xlink:href="note-0566-03a" xml:space="preserve">Pierres de <lb/>taille.</note> </div> <p> <s xml:id="echoid-s12125" xml:space="preserve">Les carreaux, qui formeront ces paremens, ſeront taillés avec ci-<lb/> <anchor type="note" xlink:label="note-0566-04a" xlink:href="note-0566-04"/> zelure relevée aux arêtes, piqués proprement à la petite pointe <lb/>dans leurs faces, auſſi-bien que dreſſés à la régle, & </s> <s xml:id="echoid-s12126" xml:space="preserve">démaigris <lb/>pour le mortier, de même que leurs lits & </s> <s xml:id="echoid-s12127" xml:space="preserve">joints; </s> <s xml:id="echoid-s12128" xml:space="preserve">ils ſeront poſés <lb/>à petits joints, & </s> <s xml:id="echoid-s12129" xml:space="preserve">bonne liaiſon, par aſſiſe reglée de neuf à dix <lb/>pouces de hauteur au moins, ſur douze à quinze pouces de lit. </s> <s xml:id="echoid-s12130" xml:space="preserve">On <lb/>aura ſoin dans l’emploi de ces carreaux, qu’ils ſoient toûjours mê-<lb/>lés d’un tiers de boutiſſes de vingt à vingt-cinq pouces de queuë, <lb/>qu’ils ayent au moins ſix pouces de joint quarré, & </s> <s xml:id="echoid-s12131" xml:space="preserve">le tout bien lié <lb/>avec le reſte de la maçonnerie.</s> <s xml:id="echoid-s12132" xml:space="preserve"/> </p> <div xml:id="echoid-div568" type="float" level="2" n="2"> <note position="left" xlink:label="note-0566-04" xlink:href="note-0566-04a" xml:space="preserve">Pierres de <lb/>parament.</note> </div> <pb o="21" file="0567" n="617" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s12133" xml:space="preserve">Les pierres des ſoubaſſemens, qui ſeront poſées au deſſus des fon-<lb/> <anchor type="note" xlink:label="note-0567-01a" xlink:href="note-0567-01"/> demens, ſeront auſſi taillées proprement dans leurs faces, lits & </s> <s xml:id="echoid-s12134" xml:space="preserve"><lb/>joints, & </s> <s xml:id="echoid-s12135" xml:space="preserve">auront douze, quinze, à dix-huit pouces de lit, & </s> <s xml:id="echoid-s12136" xml:space="preserve">huit <lb/>à dix de joint à l’équerre. </s> <s xml:id="echoid-s12137" xml:space="preserve">Seront de plus mêlées d’un tiers de bou-<lb/>tiſſes qui auront au moins deux pieds de queuë, le tout poſé en <lb/>bonne liaiſon, à petits joints & </s> <s xml:id="echoid-s12138" xml:space="preserve">en bain de mortier.</s> <s xml:id="echoid-s12139" xml:space="preserve"/> </p> <div xml:id="echoid-div569" type="float" level="2" n="3"> <note position="right" xlink:label="note-0567-01" xlink:href="note-0567-01a" xml:space="preserve">Pierres de <lb/>ſoubaſſe. <lb/>mens.</note> </div> <p> <s xml:id="echoid-s12140" xml:space="preserve">Tous les angles ſaillans, tant du corps de la Place que des con-<lb/> <anchor type="note" xlink:label="note-0567-02a" xlink:href="note-0567-02"/> tregardes, tenailles, demi-lunes, ouvrages à cornes, & </s> <s xml:id="echoid-s12141" xml:space="preserve">reduits, ſe-<lb/>ront armés de pierres de taille de graiſſerie, taillées en petit boſſage <lb/>d’un pouce & </s> <s xml:id="echoid-s12142" xml:space="preserve">demi de relief, & </s> <s xml:id="echoid-s12143" xml:space="preserve">poſées par aſſiſes reglées d’un pied <lb/>de hauteur, ayant les joints d’équerre ſur dix-huit pouces de long, <lb/>deux pieds de lit, & </s> <s xml:id="echoid-s12144" xml:space="preserve">trois de queuë, le tout mêlé d’un tiers de bou-<lb/>tiſſes, retourné & </s> <s xml:id="echoid-s12145" xml:space="preserve">poſé alternativement, de maniere qu’il ſe trouve <lb/>de chaque côté des harpies d’un pied élevées à l’aplomb par les <lb/>bouts les unes ſur les autres, & </s> <s xml:id="echoid-s12146" xml:space="preserve">que les aſſiſes les plus courtes re-<lb/>viennent ſous le cordon à quatre pieds de longueur de part & </s> <s xml:id="echoid-s12147" xml:space="preserve">d’au-<lb/>tre des angles.</s> <s xml:id="echoid-s12148" xml:space="preserve"/> </p> <div xml:id="echoid-div570" type="float" level="2" n="4"> <note position="right" xlink:label="note-0567-02" xlink:href="note-0567-02a" xml:space="preserve">Pierres des <lb/>angles.</note> </div> <p> <s xml:id="echoid-s12149" xml:space="preserve">Les cordons ſeront auſſi de pierres de taille de graiſſerie d’un <lb/> <anchor type="note" xlink:label="note-0567-03a" xlink:href="note-0567-03"/> pied de hauteur, taillées en demi rond, & </s> <s xml:id="echoid-s12150" xml:space="preserve">poſées en ſaillie de la <lb/>moitié de leur diametre, ayant les joints d’équerre ſur ſeize à dix-<lb/>huit pouces de long, & </s> <s xml:id="echoid-s12151" xml:space="preserve">deux pieds de lit, non compris la ſaillie, <lb/>le tout mêlé d’un tiers de boutiſſes qui auront trois pieds de queuë.</s> <s xml:id="echoid-s12152" xml:space="preserve"/> </p> <div xml:id="echoid-div571" type="float" level="2" n="5"> <note position="right" xlink:label="note-0567-03" xlink:href="note-0567-03a" xml:space="preserve">Cordons.</note> </div> <p> <s xml:id="echoid-s12153" xml:space="preserve">Tous les autres moëlons, dont on ſe ſervira pour remplir & </s> <s xml:id="echoid-s12154" xml:space="preserve">garnir <lb/> <anchor type="note" xlink:label="note-0567-04a" xlink:href="note-0567-04"/> le corps de la maçonnerie brute, ſeront tirés ou. </s> <s xml:id="echoid-s12155" xml:space="preserve">de l’excavation <lb/>du foſſé, ou des carrieres de .</s> <s xml:id="echoid-s12156" xml:space="preserve">..</s> <s xml:id="echoid-s12157" xml:space="preserve">. obſervant de choiſir les plus gros <lb/>libages pour en former les fondemens, & </s> <s xml:id="echoid-s12158" xml:space="preserve">de réſerver les moindres <lb/>pour le revêtement au deſſus, comme auſſi d’arraſer de niveau <lb/>toute la maçonnerie à chaque levée que l’on fera de dix-huit pou-<lb/>ces, & </s> <s xml:id="echoid-s12159" xml:space="preserve">de la traverſer, s’il eſt jugé néceſſaire pour plus grande ſo-<lb/>lidité, par des chaînes de brique ſur toute l’épaiſſeur des murs, <lb/>ce qui formera un renouvellement d’aſſiette.</s> <s xml:id="echoid-s12160" xml:space="preserve"/> </p> <div xml:id="echoid-div572" type="float" level="2" n="6"> <note position="right" xlink:label="note-0567-04" xlink:href="note-0567-04a" xml:space="preserve">Moëlon.</note> </div> <p> <s xml:id="echoid-s12161" xml:space="preserve">Les cailloux de la riviere de .</s> <s xml:id="echoid-s12162" xml:space="preserve">..</s> <s xml:id="echoid-s12163" xml:space="preserve">. ou de la plaine de .</s> <s xml:id="echoid-s12164" xml:space="preserve">..</s> <s xml:id="echoid-s12165" xml:space="preserve">. & </s> <s xml:id="echoid-s12166" xml:space="preserve">ceux <lb/> <anchor type="note" xlink:label="note-0567-05a" xlink:href="note-0567-05"/> qui ſe trouveront dans les excavations, pourront auſſi être em-<lb/>ployés dans la garniture du corps de la maçonnerie, en les poſant <lb/>par aſſiſes reglées, mais en cas de beſoin ſeulement, & </s> <s xml:id="echoid-s12167" xml:space="preserve">au défaut <lb/>de moëlon, encore faudra-t’il que la quantité de ces cailloux n’ex-<lb/>cede pas le tiers du ſolide de la maçonnerie, & </s> <s xml:id="echoid-s12168" xml:space="preserve">que chaque levée <lb/>de dix-huit pouces de hauteur ſoit auſſi recouverte d’une chaîne <lb/>de brique.</s> <s xml:id="echoid-s12169" xml:space="preserve"/> </p> <div xml:id="echoid-div573" type="float" level="2" n="7"> <note position="right" xlink:label="note-0567-05" xlink:href="note-0567-05a" xml:space="preserve">Cailloux.</note> </div> <p> <s xml:id="echoid-s12170" xml:space="preserve">Toutes ces pierres en general ſeront proprement aſſiſes & </s> <s xml:id="echoid-s12171" xml:space="preserve">bien <lb/> <anchor type="note" xlink:label="note-0567-06a" xlink:href="note-0567-06"/> callées aux paremens, poſées, coulées, fichées, & </s> <s xml:id="echoid-s12172" xml:space="preserve">jointoyées les <pb o="22" file="0568" n="618" rhead="LA SCIENCE DES INGENIEURS,"/> unes en mortier de ciment, les autres en mortier de chaux & </s> <s xml:id="echoid-s12173" xml:space="preserve">ſable, <lb/>ſuivant que les qualités de l’ouvrage l’exigeront. </s> <s xml:id="echoid-s12174" xml:space="preserve">Les libages & </s> <s xml:id="echoid-s12175" xml:space="preserve">moë-<lb/>lons de rempliſſage ſeront poſés dans le maſſif des revêtemens à <lb/>bain de mortier, avec de bonnes liaiſons de quatre à cinq pouces <lb/>au moins les unes contre les autres, & </s> <s xml:id="echoid-s12176" xml:space="preserve">d’autant des unes ſur les <lb/>autres.</s> <s xml:id="echoid-s12177" xml:space="preserve"/> </p> <div xml:id="echoid-div574" type="float" level="2" n="8"> <note position="right" xlink:label="note-0567-06" xlink:href="note-0567-06a" xml:space="preserve">Fichage <lb/>des pierres.</note> </div> <p> <s xml:id="echoid-s12178" xml:space="preserve">A l’égard des revêtemens qui ſe feront en parement de brique, <lb/> <anchor type="note" xlink:label="note-0568-01a" xlink:href="note-0568-01"/> on n’y employera que les neuves & </s> <s xml:id="echoid-s12179" xml:space="preserve">les mieux cuites, & </s> <s xml:id="echoid-s12180" xml:space="preserve">de la meil-<lb/>leure qualité, dont les plus belles ſeront choiſies pour former le <lb/>parement, & </s> <s xml:id="echoid-s12181" xml:space="preserve">poſées par aſſiſes liaiſonnées ſur cinq rangs de hau-<lb/>teur, élevées par diminution d’une demie brique à chaque rang, <lb/>c’eſt-à-dire, depuis trois briques & </s> <s xml:id="echoid-s12182" xml:space="preserve">demie au premier rang, juſ-<lb/>qu’à une & </s> <s xml:id="echoid-s12183" xml:space="preserve">demie au cinquiéme; </s> <s xml:id="echoid-s12184" xml:space="preserve">obſervant de bien froter ces <lb/>briques, & </s> <s xml:id="echoid-s12185" xml:space="preserve">de les dreſſer l’une contre l’autre avant que de <lb/>les employer; </s> <s xml:id="echoid-s12186" xml:space="preserve">& </s> <s xml:id="echoid-s12187" xml:space="preserve">qu’il y ait toûjours moitié de boutiſſes en pare-<lb/>mens. </s> <s xml:id="echoid-s12188" xml:space="preserve">Si l’on employe des cailloux dans le corps de la maçonnerie <lb/>faute de moëlon, on fera, comme il vient d’être dit, à chaque le-<lb/>vée de dix-huit pouces, une chaîne ou recouvrement de deux bri-<lb/>ques de hauteur, qui garnira toute la ſurface du revêtement & </s> <s xml:id="echoid-s12189" xml:space="preserve"><lb/>des contreforts, & </s> <s xml:id="echoid-s12190" xml:space="preserve">traverſera toute leur épaiſſeur. </s> <s xml:id="echoid-s12191" xml:space="preserve">Le premier rang <lb/>qu’on poſera enſuite en parement au deſſus de ladite chaîne, re-<lb/>commencera par trois briques & </s> <s xml:id="echoid-s12192" xml:space="preserve">demie d’épaiſſeur, finiſſant toû-<lb/>jours par une demie.</s> <s xml:id="echoid-s12193" xml:space="preserve"/> </p> <div xml:id="echoid-div575" type="float" level="2" n="9"> <note position="left" xlink:label="note-0568-01" xlink:href="note-0568-01a" xml:space="preserve">Briques.</note> </div> </div> <div xml:id="echoid-div577" type="section" level="1" n="151"> <head xml:id="echoid-head368" xml:space="preserve"><emph style="sc">Placage, et</emph> <emph style="sc">Gazonnage</emph>.</head> <p> <s xml:id="echoid-s12194" xml:space="preserve">Le placage ſera fait de terre noire de jardin ou de labeur, non <lb/> <anchor type="note" xlink:label="note-0568-02a" xlink:href="note-0568-02"/> pierreuſe: </s> <s xml:id="echoid-s12195" xml:space="preserve">il aura ſix pouces d’épaiſſeur, & </s> <s xml:id="echoid-s12196" xml:space="preserve">non taluant de huit <lb/>pouces par pied.</s> <s xml:id="echoid-s12197" xml:space="preserve"/> </p> <div xml:id="echoid-div577" type="float" level="2" n="1"> <note position="left" xlink:label="note-0568-02" xlink:href="note-0568-02a" xml:space="preserve">Placage.</note> </div> <p> <s xml:id="echoid-s12198" xml:space="preserve">Le gazon ſera coupé de biais en prez bien herbus & </s> <s xml:id="echoid-s12199" xml:space="preserve">racineux, ou <lb/> <anchor type="note" xlink:label="note-0568-03a" xlink:href="note-0568-03"/> vieilles pâtures un peu humides, & </s> <s xml:id="echoid-s12200" xml:space="preserve">non tourbeuſes, ni ſabloneuſes. <lb/></s> <s xml:id="echoid-s12201" xml:space="preserve">On poſera de trois lits en trois lits une couche de faſcines, & </s> <s xml:id="echoid-s12202" xml:space="preserve">cha-<lb/>cun de ces lits ſera bien garni de terre ſur toute ſa hauteur, & </s> <s xml:id="echoid-s12203" xml:space="preserve">bien <lb/>battu à la dame, pour être lié parfaitement avec les terres du <lb/>rempart.</s> <s xml:id="echoid-s12204" xml:space="preserve"/> </p> <div xml:id="echoid-div578" type="float" level="2" n="2"> <note position="left" xlink:label="note-0568-03" xlink:href="note-0568-03a" xml:space="preserve">Gazon.</note> </div> </div> <div xml:id="echoid-div580" type="section" level="1" n="152"> <head xml:id="echoid-head369" xml:space="preserve"><emph style="sc">Bois</emph>.</head> <p> <s xml:id="echoid-s12205" xml:space="preserve">La charpente des ponts dormans, ponts-levis, & </s> <s xml:id="echoid-s12206" xml:space="preserve">barriere, de mê-<lb/> <anchor type="note" xlink:label="note-0568-04a" xlink:href="note-0568-04"/> me que celle des madriers des fondemens de toutes les principales <lb/>parties des Bâtimens, ſera de bois de chêne bien ſain, coupé en <lb/>bonne ſaiſon, & </s> <s xml:id="echoid-s12207" xml:space="preserve">bien équarri à vive arête ſans aubier, non piqué, <pb o="23" file="0569" n="619" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> ni échauffé, roulé, vermineux, ni trop nouveau, non plus que <lb/>ſur le retour, mais de bon âge, de droit fil, & </s> <s xml:id="echoid-s12208" xml:space="preserve">de bon emploi.</s> <s xml:id="echoid-s12209" xml:space="preserve"/> </p> <div xml:id="echoid-div580" type="float" level="2" n="1"> <note position="left" xlink:label="note-0568-04" xlink:href="note-0568-04a" xml:space="preserve">Bois.</note> </div> </div> <div xml:id="echoid-div582" type="section" level="1" n="153"> <head xml:id="echoid-head370" xml:space="preserve">IV. <lb/>CONSTRUCTION DES OUVRAGES. <lb/><emph style="sc">Courtines</emph>.</head> <p> <s xml:id="echoid-s12210" xml:space="preserve">APrès que les alignemens auront été donnés & </s> <s xml:id="echoid-s12211" xml:space="preserve">rectifiés par l’In-<lb/> <anchor type="note" xlink:label="note-0569-01a" xlink:href="note-0569-01"/> genieur, qui aura la principale conduite des ouvrages, ils <lb/>ſeront montrés aux Entreprenneurs qui feront faire auſſi-tôt les <lb/>déblais des revétemens de toute l’enceinte de la Place, ſur quinze <lb/>à ſeize pieds de profondeur au deſſous du niveau des chemins cou-<lb/>verts, & </s> <s xml:id="echoid-s12212" xml:space="preserve">comprendront en même tems la moitié de la largeur des <lb/>foſſez, reſervant l’autre pour être remblayée derriere les revête-<lb/>mens, à meſure qu’ils s’éleveront. </s> <s xml:id="echoid-s12213" xml:space="preserve">Enſuite de quoi ſeront appro-<lb/>fondis les fondemens de trois pieds au deſſous du foſſé, & </s> <s xml:id="echoid-s12214" xml:space="preserve">plus bas, <lb/>s’il eſt néceſſaire, pour trouver le fond ſolide, dont les terres, ainſi <lb/>que celles qui proviendront des autres déblais, ſeront portées à la <lb/>maſſe des remparts, où elles ſeront dreſſées par lit d’un pied de <lb/>hauteur ſur toute l’étenduë des alignemens, & </s> <s xml:id="echoid-s12215" xml:space="preserve">dans l’ordre qu’il <lb/>ſera expliqué ci-près.</s> <s xml:id="echoid-s12216" xml:space="preserve"/> </p> <div xml:id="echoid-div582" type="float" level="2" n="1"> <note position="right" xlink:label="note-0569-01" xlink:href="note-0569-01a" xml:space="preserve">Deblais des <lb/>fondemens.</note> </div> <p> <s xml:id="echoid-s12217" xml:space="preserve">Pour prévenir les affaiſſemens que la tranſpiration des eaux de.</s> <s xml:id="echoid-s12218" xml:space="preserve">..</s> <s xml:id="echoid-s12219" xml:space="preserve">. <lb/> <anchor type="note" xlink:label="note-0569-02a" xlink:href="note-0569-02"/> pourroit cauſer, on aſſûrera le fond des fondemens par un rang de <lb/>madriers de bois de chêne de quatre à douze pouces de groſſeur, <lb/>qui ſera poſé ſur le devant, & </s> <s xml:id="echoid-s12220" xml:space="preserve">fera ſaillie d’un pouce au dehors du <lb/>nud du mur. </s> <s xml:id="echoid-s12221" xml:space="preserve">Que ſi quelque partie des fondemens ſe trouve ten-<lb/>dre ou douteuſe, on continuëra de mettre un rang de madriers <lb/>ſur le milieu & </s> <s xml:id="echoid-s12222" xml:space="preserve">ſur le derriere du revêtement. </s> <s xml:id="echoid-s12223" xml:space="preserve">Enfin ſi le fond ſe <lb/>trouve trop foible, on le fortifiera par un grillage de charpente <lb/>compoſé de longrines & </s> <s xml:id="echoid-s12224" xml:space="preserve">racineaux de bois de chêne, ou ſapin rou-<lb/>ge, de neuf à dix pouces de gros, aſſemblés à leur extrémité par <lb/>entaille à queuë d’hironde, & </s> <s xml:id="echoid-s12225" xml:space="preserve">tenus en raiſon par un rang de pi-<lb/>lots-de-garde battus ſur le devant au refus du mouton; </s> <s xml:id="echoid-s12226" xml:space="preserve">ce qui <lb/> <anchor type="note" xlink:label="note-0569-03a" xlink:href="note-0569-03"/> étant ainſi préparé, & </s> <s xml:id="echoid-s12227" xml:space="preserve">les fondemens dreſſés à plomb par dehors <lb/>& </s> <s xml:id="echoid-s12228" xml:space="preserve">par dedans, & </s> <s xml:id="echoid-s12229" xml:space="preserve">mis bien de niveau par devant avec ſix pouces <lb/>de pente par derriere, on les remplira de bonne & </s> <s xml:id="echoid-s12230" xml:space="preserve">ſolide maçon-<lb/>nerie conſtruite des plus gros libages & </s> <s xml:id="echoid-s12231" xml:space="preserve">moëlons qui ſe pourront <lb/>trouver, leſquels ſeront bien garnis & </s> <s xml:id="echoid-s12232" xml:space="preserve">poſés en bain de mortier <lb/>compoſé comme il eſt dit ci-devant, de ſorte qu’il ne reſte aucun <pb o="24" file="0570" n="620" rhead="LA SCIENCE DES INGENIEURS,"/> vuide dans le corps de la maçonnerie, & </s> <s xml:id="echoid-s12233" xml:space="preserve">que preſſant les pierres de <lb/>la main & </s> <s xml:id="echoid-s12234" xml:space="preserve">du marteau, le mortier ſouffle de toute part; </s> <s xml:id="echoid-s12235" xml:space="preserve">ce qui <lb/>doit être obſervé dans tout le compoſé de la maçonnerie, de mê-<lb/>me que les retraites ſur le devant.</s> <s xml:id="echoid-s12236" xml:space="preserve"/> </p> <div xml:id="echoid-div583" type="float" level="2" n="2"> <note position="right" xlink:label="note-0569-02" xlink:href="note-0569-02a" xml:space="preserve">Madriers. <lb/>en fonde-<lb/>ment.</note> <note position="right" xlink:label="note-0569-03" xlink:href="note-0569-03a" xml:space="preserve">Fondement.</note> </div> <p> <s xml:id="echoid-s12237" xml:space="preserve">Sur la ſeconde de ces retraites, & </s> <s xml:id="echoid-s12238" xml:space="preserve">à trois pouces près de ſon <lb/> <anchor type="note" xlink:label="note-0570-01a" xlink:href="note-0570-01"/> bord exterieur, ſeront poſées en parement, ſuivant le talud du re-<lb/>vêtement, trois aſſiſes de pierre de taille de façon & </s> <s xml:id="echoid-s12239" xml:space="preserve">qualité ſuſ-<lb/>dites, qui formeront un ſoubaſſement de trois pieds de hauteur, <lb/>dont le ſommet ſera taillé en chanfrain de deux pouces, & </s> <s xml:id="echoid-s12240" xml:space="preserve">bien <lb/>garni par derriere au deſſus du quel ſera fait parement net de <lb/>moëlon piqué, garni de groſſe maçonnerie qui ſera élevée juſqu’au <lb/>deſſus du cordon avec talud d’un ſur ſix par devant, & </s> <s xml:id="echoid-s12241" xml:space="preserve">à plomb <lb/>par derriere; </s> <s xml:id="echoid-s12242" xml:space="preserve">on obſervera de maçonner le parement de ce ſou-<lb/>baſſement en mortier de ciment, & </s> <s xml:id="echoid-s12243" xml:space="preserve">de jointoyer de même tout ce <lb/>qui ſera expoſé aux flots de l’eau.</s> <s xml:id="echoid-s12244" xml:space="preserve"/> </p> <div xml:id="echoid-div584" type="float" level="2" n="3"> <note position="left" xlink:label="note-0570-01" xlink:href="note-0570-01a" xml:space="preserve">Soubaſſe-<lb/>mens.</note> </div> <p> <s xml:id="echoid-s12245" xml:space="preserve">On établira en même tems les contreforts ſuivant l’Ordre de leur <lb/> <anchor type="note" xlink:label="note-0570-02a" xlink:href="note-0570-02"/> diſtribution, & </s> <s xml:id="echoid-s12246" xml:space="preserve">on les fondera auſſi bas que le revêtement, pour <lb/>les élever enſuite à la hauteur du deſſus du même cordon à plomb <lb/>de deux côtés & </s> <s xml:id="echoid-s12247" xml:space="preserve">avec ébraſement égal de part & </s> <s xml:id="echoid-s12248" xml:space="preserve">d’autre d’après <lb/>leur milieu, au ſurplus conſtruits & </s> <s xml:id="echoid-s12249" xml:space="preserve">maçonnés comme le corps des <lb/>revêtemens, à l’exception des paremens qui ſeront aſſis de hazard <lb/>& </s> <s xml:id="echoid-s12250" xml:space="preserve">ſoumis ſeulement aux ſimples alignemens des cordeaux.</s> <s xml:id="echoid-s12251" xml:space="preserve"/> </p> <div xml:id="echoid-div585" type="float" level="2" n="4"> <note position="left" xlink:label="note-0570-02" xlink:href="note-0570-02a" xml:space="preserve">Contre-<lb/>forts.</note> </div> <p> <s xml:id="echoid-s12252" xml:space="preserve">Le ſommet de ces revêtemens ſera terminé par un cordon de <lb/> <anchor type="note" xlink:label="note-0570-03a" xlink:href="note-0570-03"/> pierre de taille des façons & </s> <s xml:id="echoid-s12253" xml:space="preserve">qualitez ci-devant énoncées, & </s> <s xml:id="echoid-s12254" xml:space="preserve">ſera <lb/>ſurmonté d’un mur de brique de quatre pieds de haut & </s> <s xml:id="echoid-s12255" xml:space="preserve">trois d’é-<lb/>paiſſeur, maçonné en bain de mortier ordinaire, qui ſervira de re-<lb/>vêtement aux parapets; </s> <s xml:id="echoid-s12256" xml:space="preserve">ce mur ſera auſſi terminé ſur toute ſon épaiſ-<lb/>ſeur par une aſſiſe de briques poſées en liaiſon alternative de quatre <lb/>briques de cant, & </s> <s xml:id="echoid-s12257" xml:space="preserve">d’autant de bout, avec pente de quatre pouces du <lb/>derriere au devant, obſervant d’y faire un larmier débordant d’un <lb/>pouce ſur le foſſé, & </s> <s xml:id="echoid-s12258" xml:space="preserve">conſtruit à petits joints en bonne liaiſon & </s> <s xml:id="echoid-s12259" xml:space="preserve"><lb/>avec mortier de ciment bien reciré à la truelle.</s> <s xml:id="echoid-s12260" xml:space="preserve"/> </p> <div xml:id="echoid-div586" type="float" level="2" n="5"> <note position="left" xlink:label="note-0570-03" xlink:href="note-0570-03a" xml:space="preserve">Cordon & <lb/>revêtement <lb/>des para-<lb/>pets.</note> </div> <p> <s xml:id="echoid-s12261" xml:space="preserve">Les angles d’épaule des petits flancs des courtines ſeront armés <lb/> <anchor type="note" xlink:label="note-0570-04a" xlink:href="note-0570-04"/> de pierres de taille conditionnées comme ci-deſſus, & </s> <s xml:id="echoid-s12262" xml:space="preserve">ſur le mi-<lb/>lieu de chaque courtine ſera fait une guérite auſſi de pierre de tail-<lb/>le ſuivant les plans & </s> <s xml:id="echoid-s12263" xml:space="preserve">profils qui en ont été arrêtés, & </s> <s xml:id="echoid-s12264" xml:space="preserve">ce qui en <lb/>ſera encore dit dans la ſuite.</s> <s xml:id="echoid-s12265" xml:space="preserve"/> </p> <div xml:id="echoid-div587" type="float" level="2" n="6"> <note position="left" xlink:label="note-0570-04" xlink:href="note-0570-04a" xml:space="preserve">Angles de <lb/>pierres de <lb/>taille.</note> </div> <p> <s xml:id="echoid-s12266" xml:space="preserve">A meſure que les revêtemens s’éleveront, on continuëra le dé-<lb/>blais des terres du foſſé, dont les plus douces ſeront choiſies & </s> <s xml:id="echoid-s12267" xml:space="preserve">mi-<lb/>ſes à part ſur le chemin couvert pour en former les parapets tant <lb/>dudit chemin couvert, que des ouvrages de la Place, & </s> <s xml:id="echoid-s12268" xml:space="preserve">le ſurplus <pb o="25" file="0571" n="621" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> ſera porté à la maſſe des remparts derriere & </s> <s xml:id="echoid-s12269" xml:space="preserve">joignant les revête-<lb/>mens & </s> <s xml:id="echoid-s12270" xml:space="preserve">contreforts, où elles ſeront rangées & </s> <s xml:id="echoid-s12271" xml:space="preserve">battues avec da-<lb/>mes du poids de vingt-cinq à trente livres, par lits de ſix pouces de <lb/>hauteur ſur douze pieds de largeur, & </s> <s xml:id="echoid-s12272" xml:space="preserve">dreſſées à chacun de ces <lb/>lits en pente de ſix pouces ſur le derriere, tant pour ſoulager ces <lb/>revêtemens du poids des terres, que pour empêcher la pénetra-<lb/>tion des eaux au pied des fondemens.</s> <s xml:id="echoid-s12273" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12274" xml:space="preserve">Le côté des terres, qui joindra la maçonnerie, relevera d’autant: <lb/></s> <s xml:id="echoid-s12275" xml:space="preserve"> <anchor type="note" xlink:label="note-0571-01a" xlink:href="note-0571-01"/> & </s> <s xml:id="echoid-s12276" xml:space="preserve">ſur chaque deux lits, faiſant enſemble un pied de hauteur, bien <lb/>battus & </s> <s xml:id="echoid-s12277" xml:space="preserve">bien dreſſés, comme il vient d’être dit, ſera poſé un rang <lb/>de faſcines, & </s> <s xml:id="echoid-s12278" xml:space="preserve">eſpacés brins à brins à deux doigts de diſtance l’un <lb/>de l’autre, le gros bout appuyé contre le derriere du revêtement, <lb/>ce qui ſera ainſi réïteré à chaque pied de hauteur juſqu’à l’entiere <lb/>élevation des remparts; </s> <s xml:id="echoid-s12279" xml:space="preserve">faiſant attention que ces remparts doivent <lb/>être élevés de trois pieds plus que les revêtemens pour les raiſons <lb/>qui ont été ſpécifiées, & </s> <s xml:id="echoid-s12280" xml:space="preserve">que leur terre-plein doit être dreſſé en <lb/>pente d’un pied & </s> <s xml:id="echoid-s12281" xml:space="preserve">demi depuis la banquette juſqu’au talud inte-<lb/>rieur, ainſi que celle du terre-plein, ſera recouverte de la moins <lb/>mauvaiſe terre qu’il ſe pourra trouver, & </s> <s xml:id="echoid-s12282" xml:space="preserve">de la plus épierrée.</s> <s xml:id="echoid-s12283" xml:space="preserve"/> </p> <div xml:id="echoid-div588" type="float" level="2" n="7"> <note position="right" xlink:label="note-0571-01" xlink:href="note-0571-01a" xml:space="preserve">Terraſſe-<lb/>ment des <lb/>Remparts.</note> </div> <p> <s xml:id="echoid-s12284" xml:space="preserve">Les parapets & </s> <s xml:id="echoid-s12285" xml:space="preserve">banquettes ſeront conſtruits dans le même ordre <lb/> <anchor type="note" xlink:label="note-0571-02a" xlink:href="note-0571-02"/> que les remparts, c’eſt-à-dire, que l’on obſervera ce qui a été dit <lb/>au ſujet du battement des terres & </s> <s xml:id="echoid-s12286" xml:space="preserve">de l’arrangement des faſcines; <lb/></s> <s xml:id="echoid-s12287" xml:space="preserve">avec cette difference, qu’on n’y employera que des terres douces, <lb/>choiſies & </s> <s xml:id="echoid-s12288" xml:space="preserve">bien épierrées: </s> <s xml:id="echoid-s12289" xml:space="preserve">que s’il ne s’en trouvoit pas ſuffiſamment <lb/>de cette qualité, il en faudroit paſſer avec des clayes aſſez fines, <lb/>pour qu’il n’y reſte aucun gravier, ni cailloutage.</s> <s xml:id="echoid-s12290" xml:space="preserve"/> </p> <div xml:id="echoid-div589" type="float" level="2" n="8"> <note position="right" xlink:label="note-0571-02" xlink:href="note-0571-02a" xml:space="preserve">Terraſſe-<lb/>ment des <lb/>parapets & <lb/>banquettes.</note> </div> <p> <s xml:id="echoid-s12291" xml:space="preserve">On gazonnera le parement interieur de ce parapet avec les pré <lb/> <anchor type="note" xlink:label="note-0571-03a" xlink:href="note-0571-03"/> cautions dont il a été parlé, & </s> <s xml:id="echoid-s12292" xml:space="preserve">le gros bout de la faſcine appuyera <lb/>ſur la queuë du gazon.</s> <s xml:id="echoid-s12293" xml:space="preserve"/> </p> <div xml:id="echoid-div590" type="float" level="2" n="9"> <note position="right" xlink:label="note-0571-03" xlink:href="note-0571-03a" xml:space="preserve">Gazonna-<lb/>ge des pa-<lb/>rapets.</note> </div> </div> <div xml:id="echoid-div592" type="section" level="1" n="154"> <head xml:id="echoid-head371" xml:space="preserve"><emph style="sc">Tours</emph> <emph style="sc">Bastionne’es</emph>.</head> <p> <s xml:id="echoid-s12294" xml:space="preserve">Les Tours baſtionnéesſeront fondées avec les mêmes précautions <lb/> <anchor type="note" xlink:label="note-0571-04a" xlink:href="note-0571-04"/> que les courtines, & </s> <s xml:id="echoid-s12295" xml:space="preserve">à la même profondeur, ſuppoſé que le fond <lb/>s’y trouve vif & </s> <s xml:id="echoid-s12296" xml:space="preserve">ſolide, auquel cas on ne changera rien à la diſ-<lb/>poſition qui a été marquée pour les fondemens du corps de la Pla-<lb/>ce, excepté que les madriers ſeront redoublés au droit des angles, <lb/>& </s> <s xml:id="echoid-s12297" xml:space="preserve">retournés de douze pieds de chaque côté. </s> <s xml:id="echoid-s12298" xml:space="preserve">Que ſi le fond ſe trouve <lb/>tendre ou douteux, après l’avoir approfondi autant qu’on aura <lb/>pû, on donnera ſix & </s> <s xml:id="echoid-s12299" xml:space="preserve">douze pouces d’épaiſſeur aux madriers, & </s> <s xml:id="echoid-s12300" xml:space="preserve"><lb/>on en poſera ſur le milieu & </s> <s xml:id="echoid-s12301" xml:space="preserve">ſur le derriere des fondemens, com- <pb o="26" file="0572" n="622" rhead="LA SCIENCE DES INGENIEURS,"/> me ſur le devant, ſinon il faudra griller; </s> <s xml:id="echoid-s12302" xml:space="preserve">& </s> <s xml:id="echoid-s12303" xml:space="preserve">s’il y a encore plus de <lb/>précaution à prendre, on couvrira la ſuperficie de la grille d’un <lb/>plancher de madriers de ſix pouces d’épaiſſeur.</s> <s xml:id="echoid-s12304" xml:space="preserve"/> </p> <div xml:id="echoid-div592" type="float" level="2" n="1"> <note position="right" xlink:label="note-0571-04" xlink:href="note-0571-04a" xml:space="preserve">Fondement <lb/>des Tours.</note> </div> <p> <s xml:id="echoid-s12305" xml:space="preserve">Au ſurplus, tout ſe fera comme il vient d’être dit pour la conſ-<lb/> <anchor type="note" xlink:label="note-0572-01a" xlink:href="note-0572-01"/> truction des courtines, & </s> <s xml:id="echoid-s12306" xml:space="preserve">on obſervera tant les deux retraites dans <lb/>les fondemens, que les trois aſſiſes de pierre de taille qui forment <lb/>le ſoubaſſement & </s> <s xml:id="echoid-s12307" xml:space="preserve">la retraite qui eſt au deſſus. </s> <s xml:id="echoid-s12308" xml:space="preserve">On fera auſſi une <lb/>retraite de trois pouces du côté des terres, & </s> <s xml:id="echoid-s12309" xml:space="preserve">cela au niveau du <lb/>dedans des Tours, qui ſera élevée de ſix pieds au deſſus du fond du <lb/>foſſé, à laquelle hauteur toute l’épaiſſeur du revêtement ſera ré-<lb/>duite à douze pieds un pouce; </s> <s xml:id="echoid-s12310" xml:space="preserve">& </s> <s xml:id="echoid-s12311" xml:space="preserve">ce revêtement continué extérieu-<lb/>rement en même parement & </s> <s xml:id="echoid-s12312" xml:space="preserve">même garniture, que celui des cour-<lb/>tines, taluant toûjours d’un ſur ſix, & </s> <s xml:id="echoid-s12313" xml:space="preserve">a plomb par derriere. </s> <s xml:id="echoid-s12314" xml:space="preserve">Le pa-<lb/>rement interieur qui formera le pied droit des voûtes, ſera fait de <lb/>brique ſur un pied & </s> <s xml:id="echoid-s12315" xml:space="preserve">demi d’épaiſſeur, & </s> <s xml:id="echoid-s12316" xml:space="preserve">ſera poſé ſur deux aſ-<lb/>ſiſes de pierre de taille qui regneront autour des faces, flancs, & </s> <s xml:id="echoid-s12317" xml:space="preserve"><lb/>gorges parallelement au plan du noyau.</s> <s xml:id="echoid-s12318" xml:space="preserve"/> </p> <div xml:id="echoid-div593" type="float" level="2" n="2"> <note position="left" xlink:label="note-0572-01" xlink:href="note-0572-01a" xml:space="preserve">Revéte-<lb/>mens.</note> </div> <p> <s xml:id="echoid-s12319" xml:space="preserve">Le cordon qui terminera ce revêtement ſera de qualité & </s> <s xml:id="echoid-s12320" xml:space="preserve">façon <lb/> <anchor type="note" xlink:label="note-0572-02a" xlink:href="note-0572-02"/> ſuſdites; </s> <s xml:id="echoid-s12321" xml:space="preserve">& </s> <s xml:id="echoid-s12322" xml:space="preserve">le parapet qui le ſurmontera ſera entierement fait de <lb/>maçonnerie de brique, dans laquelle ſeront pratiquées quatre em-<lb/>braſures, deux à chaque flanc auſſi à parement de briques choiſies, <lb/>frottées l’une contre l’autre juſqu’à ce qu’elles ſoient bien droites, <lb/>& </s> <s xml:id="echoid-s12323" xml:space="preserve">poſées enſuite de cant & </s> <s xml:id="echoid-s12324" xml:space="preserve">debout en bonne liaiſon ſur trois pieds <lb/>d’épaiſſeur, tant par le fond que par les côtés; </s> <s xml:id="echoid-s12325" xml:space="preserve">& </s> <s xml:id="echoid-s12326" xml:space="preserve">ces embraſures <lb/>ſeront réglées ſuivant les meſures de leurs plans & </s> <s xml:id="echoid-s12327" xml:space="preserve">profils, avec <lb/>leurs rempes & </s> <s xml:id="echoid-s12328" xml:space="preserve">plongées; </s> <s xml:id="echoid-s12329" xml:space="preserve">ce qui s’obſervera de même pour les em-<lb/>braſures du bas étage. </s> <s xml:id="echoid-s12330" xml:space="preserve">Enfin, ledit parapet ſera terminé par une aſ-<lb/>ſiſe de briques poſées alternativement de cant & </s> <s xml:id="echoid-s12331" xml:space="preserve">debout, faiſant <lb/>ſaillie d’un pouce ſur le foſſé, & </s> <s xml:id="echoid-s12332" xml:space="preserve">maçonnées en bain de ciment <lb/>compoſé comme il eſt dit.</s> <s xml:id="echoid-s12333" xml:space="preserve"/> </p> <div xml:id="echoid-div594" type="float" level="2" n="3"> <note position="left" xlink:label="note-0572-02" xlink:href="note-0572-02a" xml:space="preserve">Parapet.</note> </div> <p> <s xml:id="echoid-s12334" xml:space="preserve">Seront auſſi conſtruits à parement de brique les évens & </s> <s xml:id="echoid-s12335" xml:space="preserve">chemi-<lb/> <anchor type="note" xlink:label="note-0572-03a" xlink:href="note-0572-03"/> nées néceſſaires pour l’évaporation de la fumée, ſuivant qu’ils ſont <lb/>marqués ſur le plan, c’eſt-à-dire, entre les embraſures du bas <lb/>étage, & </s> <s xml:id="echoid-s12336" xml:space="preserve">chacun de ces évens aura trois pieds de longueur ſur <lb/>neuf pouces de largeur par le bas, revenant à ſix pouces par le <lb/>haut, où il débouchera dans l’épaiſſeur des parapets.</s> <s xml:id="echoid-s12337" xml:space="preserve"/> </p> <div xml:id="echoid-div595" type="float" level="2" n="4"> <note position="left" xlink:label="note-0572-03" xlink:href="note-0572-03a" xml:space="preserve">Evens.</note> </div> <p> <s xml:id="echoid-s12338" xml:space="preserve">On a dit en ſon lieu quelles doivent être les dimenſions des ban-<lb/> <anchor type="note" xlink:label="note-0572-04a" xlink:href="note-0572-04"/> quettes de ces pieces, on obſervera ſeulement qu’elles ſoient tou-<lb/>tes de maçonnerie.</s> <s xml:id="echoid-s12339" xml:space="preserve"/> </p> <div xml:id="echoid-div596" type="float" level="2" n="5"> <note position="left" xlink:label="note-0572-04" xlink:href="note-0572-04a" xml:space="preserve">Banquettes.</note> </div> <p> <s xml:id="echoid-s12340" xml:space="preserve">Les angles du parement exterieur ſeront tous armés de pierres de <lb/> <anchor type="note" xlink:label="note-0572-05a" xlink:href="note-0572-05"/> taille de façon & </s> <s xml:id="echoid-s12341" xml:space="preserve">qualité ſuſdites, & </s> <s xml:id="echoid-s12342" xml:space="preserve">ſur l’angle flanqué de chaque <pb o="27" file="0573" n="623" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> Tour ſera faite une guerite auſſi de pierre de taille, conformement <lb/>à ce qui ſera dit ci-après.</s> <s xml:id="echoid-s12343" xml:space="preserve"/> </p> <div xml:id="echoid-div597" type="float" level="2" n="6"> <note position="left" xlink:label="note-0572-05" xlink:href="note-0572-05a" xml:space="preserve">Angles & <lb/>guerites.</note> </div> <p> <s xml:id="echoid-s12344" xml:space="preserve">Le noyau ſera fondé auſſi bas que les autres parties de la Tour, <lb/> <anchor type="note" xlink:label="note-0573-01a" xlink:href="note-0573-01"/> & </s> <s xml:id="echoid-s12345" xml:space="preserve">avec les mêmes précautions. </s> <s xml:id="echoid-s12346" xml:space="preserve">Il ſera élevé à parement brute juſ-<lb/>qu’au niveau du rez-de-chauſſée interieur de ladite Tour, & </s> <s xml:id="echoid-s12347" xml:space="preserve">après <lb/>que ſes alignemens auront été dreſſés, & </s> <s xml:id="echoid-s12348" xml:space="preserve">ſes pans réduits à leur <lb/>juſte meſure, on fera parement net par deux aſſiſes de pierre de tail-<lb/>le, qui regneront tout autour parallelement à l’interieur des flancs, <lb/>faces, & </s> <s xml:id="echoid-s12349" xml:space="preserve">gorges, de même qu’autour des côtés du Magazin à pou-<lb/>dre, puis on élevera le ſurplus de la hauteur en groſſe maçonne-<lb/>rie avec parement de brique d’un pied & </s> <s xml:id="echoid-s12350" xml:space="preserve">demi d’épaiſſeur, & </s> <s xml:id="echoid-s12351" xml:space="preserve">à <lb/>plomb de quatre pieds & </s> <s xml:id="echoid-s12352" xml:space="preserve">demi au deſſus des fondemens, à laquelle <lb/>hauteur la maçonnerie ſera proprement arraſée & </s> <s xml:id="echoid-s12353" xml:space="preserve">diſpoſée pour <lb/>commencer la naiſſance des voûtes.</s> <s xml:id="echoid-s12354" xml:space="preserve"/> </p> <div xml:id="echoid-div598" type="float" level="2" n="7"> <note position="right" xlink:label="note-0573-01" xlink:href="note-0573-01a" xml:space="preserve">Noyau.</note> </div> <p> <s xml:id="echoid-s12355" xml:space="preserve">Les angles du noyau ſeront auſſi de pierres de taille poſées par <lb/> <anchor type="note" xlink:label="note-0573-02a" xlink:href="note-0573-02"/> aſſiſes retournées de de ux en trois; </s> <s xml:id="echoid-s12356" xml:space="preserve">on obſervera la même conſtruc-<lb/>tion aux gorges des Tours qu’à leur noyau, c’eſt-à-dire, même <lb/>parement, même garniture, même profondeur des fondemens, & </s> <s xml:id="echoid-s12357" xml:space="preserve"><lb/>même retraite. </s> <s xml:id="echoid-s12358" xml:space="preserve">Au milieu de ces gorges & </s> <s xml:id="echoid-s12359" xml:space="preserve">au niveau du rez-de-<lb/>chauſſée de ces Tours, ſera fait une porte de huit pieds de largeur <lb/>ſur huit & </s> <s xml:id="echoid-s12360" xml:space="preserve">demi de hauteur, dont les pieds droits & </s> <s xml:id="echoid-s12361" xml:space="preserve">vouſſoirs ſe-<lb/>ront de pierre de taille, ainſi que les ſeüils & </s> <s xml:id="echoid-s12362" xml:space="preserve">arrieres-vouſſoirs. <lb/></s> <s xml:id="echoid-s12363" xml:space="preserve">On aura attention d’y faire double feüilleure, & </s> <s xml:id="echoid-s12364" xml:space="preserve">de pratiquer à cha-<lb/>cun de ces côtés des creneaux plongeans & </s> <s xml:id="echoid-s12365" xml:space="preserve">bien voyans dans leſ-<lb/>dites Tours. </s> <s xml:id="echoid-s12366" xml:space="preserve">Ce paſſage ſera fermé par une porte de bois de chêne <lb/>de quatre pouces d’épaiſſeur, garnie de ferrures & </s> <s xml:id="echoid-s12367" xml:space="preserve">verroüils de <lb/>force ſuffiſante, & </s> <s xml:id="echoid-s12368" xml:space="preserve">de deux bonnes ſerrures; </s> <s xml:id="echoid-s12369" xml:space="preserve">ſera fait une pareille <lb/>ouverture dans le milieu de cette gorge au niveau du rempart, <lb/>avec une fermeture auſſi de bois de chêne, garnie des ferrures né-<lb/>ceſſaires, le tout de force convenable.</s> <s xml:id="echoid-s12370" xml:space="preserve"/> </p> <div xml:id="echoid-div599" type="float" level="2" n="8"> <note position="right" xlink:label="note-0573-02" xlink:href="note-0573-02a" xml:space="preserve">Gorges.</note> </div> <p> <s xml:id="echoid-s12371" xml:space="preserve">L’intervale qui ſe trouvera entre les noyaux des Tours & </s> <s xml:id="echoid-s12372" xml:space="preserve">leurs <lb/> <anchor type="note" xlink:label="note-0573-03a" xlink:href="note-0573-03"/> faces, flancs, & </s> <s xml:id="echoid-s12373" xml:space="preserve">gorges, ſera voûté à plein-ceintre ſur dix-huit pieds <lb/>de largeur, & </s> <s xml:id="echoid-s12374" xml:space="preserve">trois & </s> <s xml:id="echoid-s12375" xml:space="preserve">demi d’épaiſſeur, le tout de brique, ſur <lb/>quoi ſera élevé en chape avec moëlon & </s> <s xml:id="echoid-s12376" xml:space="preserve">mortier de chaux & </s> <s xml:id="echoid-s12377" xml:space="preserve">ſable, <lb/>la maçonnerie du couronnement des voûtes, dont la pente ſera <lb/>prolongée de part & </s> <s xml:id="echoid-s12378" xml:space="preserve">d’autre pour donner del’écoulement aux eaux; <lb/></s> <s xml:id="echoid-s12379" xml:space="preserve">cette pente aboutira à un petit ruiſſeau qui ſera formé le long des <lb/>parapets à un pied & </s> <s xml:id="echoid-s12380" xml:space="preserve">demi, puis les eaux s’écouleront dans le foſſé <lb/>par le moyen de quelques gargoüilles, qui les porteront à trois <lb/>pieds au-delà du talud des revêtemens; </s> <s xml:id="echoid-s12381" xml:space="preserve">on voûtera de même le <lb/>Magaſin à poudre ſur toute ſa largeur, & </s> <s xml:id="echoid-s12382" xml:space="preserve">on y pratiquera les por-<lb/>tes & </s> <s xml:id="echoid-s12383" xml:space="preserve">évens néceſſaires.</s> <s xml:id="echoid-s12384" xml:space="preserve"/> </p> <div xml:id="echoid-div600" type="float" level="2" n="9"> <note position="right" xlink:label="note-0573-03" xlink:href="note-0573-03a" xml:space="preserve">Voûtes.</note> </div> <pb o="28" file="0574" n="624" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s12385" xml:space="preserve">Les voûtes étant terminées, on les couvrira ſur toute leur lon-<lb/> <anchor type="note" xlink:label="note-0574-01a" xlink:href="note-0574-01"/> gueur & </s> <s xml:id="echoid-s12386" xml:space="preserve">largeur d’une chape de ciment.</s> <s xml:id="echoid-s12387" xml:space="preserve"/> </p> <div xml:id="echoid-div601" type="float" level="2" n="10"> <note position="left" xlink:label="note-0574-01" xlink:href="note-0574-01a" xml:space="preserve">Chapes de <lb/>Ciment.</note> </div> <p> <s xml:id="echoid-s12388" xml:space="preserve">L’ouvrage étant bien conditionné & </s> <s xml:id="echoid-s12389" xml:space="preserve">exactement viſité, on ter-<lb/> <anchor type="note" xlink:label="note-0574-02a" xlink:href="note-0574-02"/> raſſera ſur les voûtes, commençant par un lit de gros ſable ou de <lb/>gravier, ſi on en a, ou de menuës recoupes de pierres de cinq à <lb/>ſix pouces d’épaiſſeur, étendu & </s> <s xml:id="echoid-s12390" xml:space="preserve">poſé également ſur toute la ſu-<lb/>perficie de la chape, & </s> <s xml:id="echoid-s12391" xml:space="preserve">continuant par un lit de terre douce d’un <lb/>pied d’épais, qu’on battra bien à la dame, & </s> <s xml:id="echoid-s12392" xml:space="preserve">qu’on rechargera <lb/>de même terre lit par lit juſqu’à l’entier terraſſement qui ſera élevé <lb/>au moins de trois pieds au deſſus de l’arête ou ſommet des chapes.</s> <s xml:id="echoid-s12393" xml:space="preserve"/> </p> <div xml:id="echoid-div602" type="float" level="2" n="11"> <note position="left" xlink:label="note-0574-02" xlink:href="note-0574-02a" xml:space="preserve">Terraſſe-<lb/>ment des <lb/>voûtes.</note> </div> <p> <s xml:id="echoid-s12394" xml:space="preserve">Les pieds droits, ou côtés des poternes de ſortie joignant les flancs <lb/> <anchor type="note" xlink:label="note-0574-03a" xlink:href="note-0574-03"/> des Tours, ſeront fondés avec les mêmes précautions & </s> <s xml:id="echoid-s12395" xml:space="preserve">ſolidité <lb/>qu’il a été dit ci-devant, & </s> <s xml:id="echoid-s12396" xml:space="preserve">ſeront élevés à plomb au deſſus de leurs <lb/>fondemens en groſſe maçonnerie, avec parement de brique d’un <lb/>pied & </s> <s xml:id="echoid-s12397" xml:space="preserve">demi d’épaiſſeur du côté de la galerie ſeulement.</s> <s xml:id="echoid-s12398" xml:space="preserve"/> </p> <div xml:id="echoid-div603" type="float" level="2" n="12"> <note position="left" xlink:label="note-0574-03" xlink:href="note-0574-03a" xml:space="preserve">Poter’nes de <lb/>ſortie.</note> </div> <p> <s xml:id="echoid-s12399" xml:space="preserve">On adoſſera l’exterieur de ces pieds droits, de pierres ou petits <lb/> <anchor type="note" xlink:label="note-0574-04a" xlink:href="note-0574-04"/> murs ſecs de deux pieds d’épaiſſeur, qui ſeront faits avec blocailles <lb/>arrangées proprement à la main ſans mortier, & </s> <s xml:id="echoid-s12400" xml:space="preserve">arraſées à chaque <lb/>levée de goiſes ou gros gravier pour en remplir les joints. </s> <s xml:id="echoid-s12401" xml:space="preserve">Ces murs <lb/>ſeront élevés juſqu’à deux pieds près de la ſuperficie du terre-plein <lb/>des remparts, & </s> <s xml:id="echoid-s12402" xml:space="preserve">ces deux pieds ſeront continuées en maçonnerie de <lb/>chaux & </s> <s xml:id="echoid-s12403" xml:space="preserve">ſable juſqu’à la rencontre de la chape de ciment, qu’il <lb/>faudra prolonger ſur toute leur épaiſſeur, afin que la tranſpiration <lb/>& </s> <s xml:id="echoid-s12404" xml:space="preserve">humidité ne ſe faſſent point ſentir dans les gros murs. </s> <s xml:id="echoid-s12405" xml:space="preserve">Il faudra <lb/>fonder ces pierrées un pied ou deux plus bas que l’aire des ſouter-<lb/>rains, & </s> <s xml:id="echoid-s12406" xml:space="preserve">on aura ſoin d’y pratiquer des conduits proprement mouſ-<lb/>ſés pour faciliter l’égout des eaux. </s> <s xml:id="echoid-s12407" xml:space="preserve">On fera auſſi de pareilles pier-<lb/>rées aux paſſages de l’entrée des Tours, & </s> <s xml:id="echoid-s12408" xml:space="preserve">à ceux des portes, po-<lb/>ternes, flancs bas, ſouterrains, & </s> <s xml:id="echoid-s12409" xml:space="preserve">generalement à tous les autres <lb/>murs qui ſoutiendront des terres, quand même ils ſeroient cou-<lb/>verts, afin que les eaux s’y raſſemblent, & </s> <s xml:id="echoid-s12410" xml:space="preserve">qu’elles ne penetrent <lb/>point dans les ſouterrains.</s> <s xml:id="echoid-s12411" xml:space="preserve"/> </p> <div xml:id="echoid-div604" type="float" level="2" n="13"> <note position="left" xlink:label="note-0574-04" xlink:href="note-0574-04a" xml:space="preserve">Piérrées.</note> </div> <p> <s xml:id="echoid-s12412" xml:space="preserve">La voûte, qui portera ſur les pieds droits de ces poternes, ſera <lb/> <anchor type="note" xlink:label="note-0574-05a" xlink:href="note-0574-05"/> conſtruite en plein-ceintre de deux pieds d’épaiſſeur ſeulement, & </s> <s xml:id="echoid-s12413" xml:space="preserve"><lb/>le ſurplus ſera de groſſe maçonnerie, & </s> <s xml:id="echoid-s12414" xml:space="preserve">élevée en demi cape contre <lb/>la gorge de la Tour, recouvrant le mur ſec, & </s> <s xml:id="echoid-s12415" xml:space="preserve">recouvert enſuite <lb/>d’une chape de ciment.</s> <s xml:id="echoid-s12416" xml:space="preserve"/> </p> <div xml:id="echoid-div605" type="float" level="2" n="14"> <note position="left" xlink:label="note-0574-05" xlink:href="note-0574-05a" xml:space="preserve">Voûtes des <lb/>poternes.</note> </div> <p> <s xml:id="echoid-s12417" xml:space="preserve">Il ſera érigé dans le ſouterrain deux portes de pierre de taille <lb/>de quatre pieds & </s> <s xml:id="echoid-s12418" xml:space="preserve">demi de largeur chacune, ſur ſept de hauteur <lb/>ſous clef, obſervant de faire dans les pieds droits les feüilleures <lb/>néceſſaires pour y appliquer les fermetures.</s> <s xml:id="echoid-s12419" xml:space="preserve"/> </p> <pb o="29" file="0575" n="625" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s12420" xml:space="preserve">Les murs du paſſage de l’entrée des Tours, auſſi-bien que leur <lb/> <anchor type="note" xlink:label="note-0575-01a" xlink:href="note-0575-01"/> ébraſement exterieur, ſeront conſtruits dans le même ordre que <lb/>les poternes, & </s> <s xml:id="echoid-s12421" xml:space="preserve">leur voûte faite en plein-ceintre de trois pieds d’é-<lb/>paiſſeur de brique, ſurmontés d’une petite chape de maçonnerie & </s> <s xml:id="echoid-s12422" xml:space="preserve"><lb/>d’une autre de ciment. </s> <s xml:id="echoid-s12423" xml:space="preserve">Les pieds droits de la porte auront chacun <lb/>dix-huit pouces de tableau, & </s> <s xml:id="echoid-s12424" xml:space="preserve">trois pieds de coinçon, ce qui fera <lb/>quatre pieds ſix pouces d’épaiſſeur de mur au deſſus des fondemens; <lb/></s> <s xml:id="echoid-s12425" xml:space="preserve">cette porte ſera voûtée à plein-ceintre, & </s> <s xml:id="echoid-s12426" xml:space="preserve">aura ſon arriere-vouſſoir <lb/>par derriere, & </s> <s xml:id="echoid-s12427" xml:space="preserve">un ſeüil de pierre de taille d’un pied d’épaiſſeur, & </s> <s xml:id="echoid-s12428" xml:space="preserve">de <lb/>la longueur des tableaux. </s> <s xml:id="echoid-s12429" xml:space="preserve">A l’égard des embraſemens, ils ſeront ter-<lb/>minés par une aſſiſe de briques poſées de cant & </s> <s xml:id="echoid-s12430" xml:space="preserve">debout en bain de <lb/>ciment, qui formera une tablette ou larmier débordant d’un pouce <lb/>ſur le devant.</s> <s xml:id="echoid-s12431" xml:space="preserve"/> </p> <div xml:id="echoid-div606" type="float" level="2" n="15"> <note position="right" xlink:label="note-0575-01" xlink:href="note-0575-01a" xml:space="preserve">Paſſage <lb/>de l’entrée <lb/>des Tours.</note> </div> <p> <s xml:id="echoid-s12432" xml:space="preserve">Toutes les portes de menuiſerie, tant des Tours que de leurs <lb/> <anchor type="note" xlink:label="note-0575-02a" xlink:href="note-0575-02"/> paſſages & </s> <s xml:id="echoid-s12433" xml:space="preserve">poternes, ſeront de bon bois de chêne bien ſec, de <lb/>deux pouces d’épaiſſeur pour les petites portes, & </s> <s xml:id="echoid-s12434" xml:space="preserve">de quatre pou-<lb/>ces pour les grandes d’aſſemblage, redoublées avec gonds & </s> <s xml:id="echoid-s12435" xml:space="preserve">fortes <lb/>pentures à queuë d’hironde, bien attachées aux portes avec un <lb/>clou rivé au collet, pluſieurs autres clous limés à tête ronde le long <lb/>des branches, & </s> <s xml:id="echoid-s12436" xml:space="preserve">trois aux extrémités des queuës d’hironde traver-<lb/>ſant toute l’épaiſſeur du bois, à pointe rabattuë & </s> <s xml:id="echoid-s12437" xml:space="preserve">contre-cognée, <lb/>le tout de force ſuffiſante, ainſi que les ſerrures & </s> <s xml:id="echoid-s12438" xml:space="preserve">autres ferrures.</s> <s xml:id="echoid-s12439" xml:space="preserve"/> </p> <div xml:id="echoid-div607" type="float" level="2" n="16"> <note position="right" xlink:label="note-0575-02" xlink:href="note-0575-02a" xml:space="preserve">Portes de <lb/>menuiſerie.</note> </div> <p> <s xml:id="echoid-s12440" xml:space="preserve">On fondera les eſcaliers qui ſeront joignans l’entrée des Tours, <lb/> <anchor type="note" xlink:label="note-0575-03a" xlink:href="note-0575-03"/> ſur un maſſif de maçonnerie de vingt & </s> <s xml:id="echoid-s12441" xml:space="preserve">un pieds de long, & </s> <s xml:id="echoid-s12442" xml:space="preserve">ſix & </s> <s xml:id="echoid-s12443" xml:space="preserve"><lb/>demi de largeur. </s> <s xml:id="echoid-s12444" xml:space="preserve">Toutes les marches ſeront de pierre de taille, ainſi <lb/>que les encognures du mur d’apui, qui ſera recouvert d’une ta-<lb/>blette auſſi de pierres de taille de ſix pouces d’épaiſſeur, & </s> <s xml:id="echoid-s12445" xml:space="preserve">deux <lb/>pieds deux pouces de largeur, bien jointes & </s> <s xml:id="echoid-s12446" xml:space="preserve">bien cramponées avec <lb/>crampons de fer coulés en plomb, & </s> <s xml:id="echoid-s12447" xml:space="preserve">proprement enchaſſés de leur <lb/>épaiſſeur dans ladite tablette.</s> <s xml:id="echoid-s12448" xml:space="preserve"/> </p> <div xml:id="echoid-div608" type="float" level="2" n="17"> <note position="right" xlink:label="note-0575-03" xlink:href="note-0575-03a" xml:space="preserve">Eſcaliers,</note> </div> <p> <s xml:id="echoid-s12449" xml:space="preserve">Le rez-de-chauſſée des Tours, auſſi-bien que celui de tous leurs <lb/> <anchor type="note" xlink:label="note-0575-04a" xlink:href="note-0575-04"/> paſſages, poternes, & </s> <s xml:id="echoid-s12450" xml:space="preserve">ſorties, ſera pavé de briques choiſies, dreſſées <lb/>l’une contre l’autre, & </s> <s xml:id="echoid-s12451" xml:space="preserve">poſées de cant en bain de mortier de chaux <lb/>& </s> <s xml:id="echoid-s12452" xml:space="preserve">ſable fin, & </s> <s xml:id="echoid-s12453" xml:space="preserve">bien de niveau: </s> <s xml:id="echoid-s12454" xml:space="preserve">quant aux Tours qui ſerviront de <lb/>Magazin à poudre, on y fera un plancher de poutrelles de huit à <lb/>neuf pouces de gros, recouvert de madriers de chêne de deux <lb/>pouces d’épaiſſeur, bien chevillés ſur les poutrelles, & </s> <s xml:id="echoid-s12455" xml:space="preserve">proprement <lb/>joints & </s> <s xml:id="echoid-s12456" xml:space="preserve">aſſemblés, ſur leſquels ſeront enſuite chevillés les chan-<lb/>tiers deſtinés à porter les barils.</s> <s xml:id="echoid-s12457" xml:space="preserve"/> </p> <div xml:id="echoid-div609" type="float" level="2" n="18"> <note position="right" xlink:label="note-0575-04" xlink:href="note-0575-04a" xml:space="preserve">Pavé dej <lb/>Tours, & <lb/>plancher.</note> </div> <pb o="30" file="0576" n="626" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div611" type="section" level="1" n="155"> <head xml:id="echoid-head372" xml:space="preserve">GRANDES PORTES, PASSAGES, ET CORPS DE <lb/><emph style="sc">Garde des</emph> <emph style="sc">Entre’es principales</emph>.</head> <p> <s xml:id="echoid-s12458" xml:space="preserve">Les façades exterieures des quatre grandes portes d’architecture, <lb/> <anchor type="note" xlink:label="note-0576-01a" xlink:href="note-0576-01"/> de même que les murs de leurs paſſages, ſeront fondés en même <lb/>tems que les revêtemens du corps de la Place, & </s> <s xml:id="echoid-s12459" xml:space="preserve">avec les mêmes <lb/>précautions. </s> <s xml:id="echoid-s12460" xml:space="preserve">Chaque façade aura neuf toiſes & </s> <s xml:id="echoid-s12461" xml:space="preserve">demie de longueur <lb/>en fondemens, ſur quatorze & </s> <s xml:id="echoid-s12462" xml:space="preserve">demie de largeur, & </s> <s xml:id="echoid-s12463" xml:space="preserve">aprés avoir <lb/>été élevée à plomb devant & </s> <s xml:id="echoid-s12464" xml:space="preserve">derriere en groſſe maçonnerie, avec <lb/>des retraites pareilles à celles des courtines, elle ſera arraſée bien <lb/>de niveau d’après le fond du foſſe2;</s> <s xml:id="echoid-s12465" xml:space="preserve">; ſur lequel arraſement ſera érigé <lb/>en pierre de taille liſſe & </s> <s xml:id="echoid-s12466" xml:space="preserve">mortier de ciment, le ſoubaſſement de <lb/>la façade avec le corps & </s> <s xml:id="echoid-s12467" xml:space="preserve">arriere-corps figurés ſur le plan, & </s> <s xml:id="echoid-s12468" xml:space="preserve">avec <lb/>talud juſqu’au rez-de-chauſſée de la Place, où il ſera terminé par <lb/>un cordon de pierre de taille de dix pouces de hauteur, & </s> <s xml:id="echoid-s12469" xml:space="preserve">de cinq <lb/>de ſaillie.</s> <s xml:id="echoid-s12470" xml:space="preserve"/> </p> <div xml:id="echoid-div611" type="float" level="2" n="1"> <note position="left" xlink:label="note-0576-01" xlink:href="note-0576-01a" xml:space="preserve">Fondemens <lb/>des ſoubaſ-<lb/>ſemens.</note> </div> <p> <s xml:id="echoid-s12471" xml:space="preserve">On obſervera, en conſtruiſant ce ſoubaſſement, de ne lui donner <lb/> <anchor type="note" xlink:label="note-0576-02a" xlink:href="note-0576-02"/> qu’un pied & </s> <s xml:id="echoid-s12472" xml:space="preserve">demi d’épaiſſeur par le haut à l’endroit du baſcula-<lb/>ge, afin que rien ne gêne le mouvement de la baſcule, dont la cage <lb/>aura douze pieds & </s> <s xml:id="echoid-s12473" xml:space="preserve">demi de largeur ſur treize de profondeur, & </s> <s xml:id="echoid-s12474" xml:space="preserve"><lb/>ſera revêtuë du côté des terres en groſſe maçonnerie d’un mur de <lb/>trois pieds & </s> <s xml:id="echoid-s12475" xml:space="preserve">demi d’épaiſſeur au deſſus de ſes fondemens, & </s> <s xml:id="echoid-s12476" xml:space="preserve">ré-<lb/>duits à deux pieds & </s> <s xml:id="echoid-s12477" xml:space="preserve">demi par le haut. </s> <s xml:id="echoid-s12478" xml:space="preserve">On obſervera encore, pour <lb/>deſcendre dans ladite cage, de pratiquer dans un de ſes côtés un <lb/>petit eſcalier voûté, de deux pieds & </s> <s xml:id="echoid-s12479" xml:space="preserve">demi de largeur; </s> <s xml:id="echoid-s12480" xml:space="preserve">& </s> <s xml:id="echoid-s12481" xml:space="preserve">de don-<lb/>ner un peu de pente au fond de la cage avec une gargoüille pour <lb/>écouler les eaux qui pourroient y ſéjourner.</s> <s xml:id="echoid-s12482" xml:space="preserve"/> </p> <div xml:id="echoid-div612" type="float" level="2" n="2"> <note position="left" xlink:label="note-0576-02" xlink:href="note-0576-02a" xml:space="preserve">Cage de <lb/>la baſcule.</note> </div> <p> <s xml:id="echoid-s12483" xml:space="preserve">Au deſſus du cordon du ſoubaſſement, ſeront erigées les façades <lb/> <anchor type="note" xlink:label="note-0576-03a" xlink:href="note-0576-03"/> des portes ſuivant les dimenſions qui ont été marquées ci-deſſus: <lb/></s> <s xml:id="echoid-s12484" xml:space="preserve">elles ſeront decorées de quatre pilaſtres d’architecture dans les pro-<lb/>portions de l’Ordre Toſcan, avec tous les refends, ſocles, baſes, <lb/>impoſtes, chapiteaux, architraves, friſes, corniches, frontons, & </s> <s xml:id="echoid-s12485" xml:space="preserve"><lb/>autres accompagnemens dudit Ordre; </s> <s xml:id="echoid-s12486" xml:space="preserve">ſeront de plus ſculptées les <lb/>Armes du Roi dans l’arcade au deſſus de la porte, & </s> <s xml:id="echoid-s12487" xml:space="preserve">la Deviſe de <lb/>Sa Majeſté dans le fronton, le tout taillé-liſſe, poſé en mortier de <lb/>ciment, bien appareillé, & </s> <s xml:id="echoid-s12488" xml:space="preserve">proprement mis en œuvre; </s> <s xml:id="echoid-s12489" xml:space="preserve">obſervant <lb/>de plus que tous les joints ſoient d’équerre ſur dix-huit pouces de <lb/>long, que les carreaux ſoient mêlés d’un tiers de boutiſſes de deux <lb/>pieds de queuë, & </s> <s xml:id="echoid-s12490" xml:space="preserve">que les arrieres-corps, écoinçons, & </s> <s xml:id="echoid-s12491" xml:space="preserve">generale-<lb/>ment toute la decoration, ſoient abſolument conformes aux plans <pb o="31" file="0577" n="627" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> & </s> <s xml:id="echoid-s12492" xml:space="preserve">aux profils. </s> <s xml:id="echoid-s12493" xml:space="preserve">Les arriere-vouſſures ſeront auſſi toutes de pierre <lb/>de taille, de même que le derriere des gros murs des portes, & </s> <s xml:id="echoid-s12494" xml:space="preserve"><lb/>les retours du haut & </s> <s xml:id="echoid-s12495" xml:space="preserve">du bas des façades.</s> <s xml:id="echoid-s12496" xml:space="preserve"/> </p> <div xml:id="echoid-div613" type="float" level="2" n="3"> <note position="left" xlink:label="note-0576-03" xlink:href="note-0576-03a" xml:space="preserve">Façades <lb/>des portes.</note> </div> <p> <s xml:id="echoid-s12497" xml:space="preserve">Les fondemens des murs qui formeront le paſſage de ces portes <lb/> <anchor type="note" xlink:label="note-0577-01a" xlink:href="note-0577-01"/> ſeront élevés juſqu’au niveau de ce paſſage; </s> <s xml:id="echoid-s12498" xml:space="preserve">puis, après avoir fait <lb/>trois pouces de retraites de chaque côté, on poſera du côté du paſ-<lb/>ſage deux aſſiſes de pierres de taille liſſe d’un pied de hauteur cha-<lb/>cune, & </s> <s xml:id="echoid-s12499" xml:space="preserve">mêlés d’un tiers de boutiſſes d’un pied & </s> <s xml:id="echoid-s12500" xml:space="preserve">demi de lon-<lb/>gueur ou environ: </s> <s xml:id="echoid-s12501" xml:space="preserve">ſur ces aſſiſes on fera une autre retraite de deux <lb/>pouces, pour élever enſuite à plomb les murs en parement de bri-<lb/>que d’un pied & </s> <s xml:id="echoid-s12502" xml:space="preserve">demi d’épaiſſeur, & </s> <s xml:id="echoid-s12503" xml:space="preserve">le ſurplus du côté des terres <lb/>en moëlon, caillou, & </s> <s xml:id="echoid-s12504" xml:space="preserve">brique juſqu’à cinq pied de hauteur, où la <lb/>maçonnerie ſera arraſée bien de niveau pour recevoir un impoſte <lb/>de pierre de taille de huit pouces de haut, ſur lequel commencera <lb/>la naiſſance des voûtes. </s> <s xml:id="echoid-s12505" xml:space="preserve">Les contreforts de ces murs ſeront fondés à <lb/>même profondeur, & </s> <s xml:id="echoid-s12506" xml:space="preserve">conſtruits de groſſe maçonnerie; </s> <s xml:id="echoid-s12507" xml:space="preserve">les doſſe-<lb/> <anchor type="note" xlink:label="note-0577-02a" xlink:href="note-0577-02"/> rets, ou arcs doubleaux, ſeront auſſi de pierre de taille, & </s> <s xml:id="echoid-s12508" xml:space="preserve">auront <lb/>deux pieds de largeur ſur deux de ſaillie; </s> <s xml:id="echoid-s12509" xml:space="preserve">ceux, dans leſquels ſe <lb/>trouvera le paſſage des orgues, auront quatre pieds dix pouces de <lb/>largeur, y compris les feüillures qui auront dix pouces d’ouvertu-<lb/>re, & </s> <s xml:id="echoid-s12510" xml:space="preserve">autant d’enfoncement, & </s> <s xml:id="echoid-s12511" xml:space="preserve">ceux du milieu du paſſage n’au-<lb/>ront que quatre pieds. </s> <s xml:id="echoid-s12512" xml:space="preserve">Ils ſeront tous eſpacés à neuf pieds & </s> <s xml:id="echoid-s12513" xml:space="preserve">demi <lb/>de diſtance les uns contre les autres, & </s> <s xml:id="echoid-s12514" xml:space="preserve">les aſſiſes, dont ils ſeront <lb/>compoſés, feront parpin entre deux une, obſervant que celles qui <lb/>ne le feront point ſoient de deux pieces ſeulement, & </s> <s xml:id="echoid-s12515" xml:space="preserve">non plus; <lb/></s> <s xml:id="echoid-s12516" xml:space="preserve">ce qui ſe continuëra juſqu’à la fermeture des arcades.</s> <s xml:id="echoid-s12517" xml:space="preserve"/> </p> <div xml:id="echoid-div614" type="float" level="2" n="4"> <note position="right" xlink:label="note-0577-01" xlink:href="note-0577-01a" xml:space="preserve">Paſſage des <lb/>entrées.</note> <note position="right" xlink:label="note-0577-02" xlink:href="note-0577-02a" xml:space="preserve">Doſſerets.</note> </div> <p> <s xml:id="echoid-s12518" xml:space="preserve">On fera une pierrée à chaque côté de ces murs, puis on com-<lb/>mencera la naiſſance des voûtes au deſſus de l’impoſte. </s> <s xml:id="echoid-s12519" xml:space="preserve">Ces voûtes <lb/>ſeront conſtruites de brique ſur deux pieds d’épaiſſeur, à petits <lb/>joints ſur le devant, & </s> <s xml:id="echoid-s12520" xml:space="preserve">groſſiſſant inſenſiblement ſur le derriere, <lb/>ſuivant la coupe de leur ceintre, puis ſeront recouvertes d’une <lb/>chape de ciment d’un pouce d’épaiſſeur; </s> <s xml:id="echoid-s12521" xml:space="preserve">mais cela, aux endroits <lb/>ſeulement où elles ne ſeront point couvertes par les bâtimens.</s> <s xml:id="echoid-s12522" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12523" xml:space="preserve">Les veſtibules & </s> <s xml:id="echoid-s12524" xml:space="preserve">corps de garde de ces paſſages ſeront fondés <lb/> <anchor type="note" xlink:label="note-0577-03a" xlink:href="note-0577-03"/> & </s> <s xml:id="echoid-s12525" xml:space="preserve">élevés avec la même attention, & </s> <s xml:id="echoid-s12526" xml:space="preserve">ſeront parfaitement confor-<lb/>mes aux meſures & </s> <s xml:id="echoid-s12527" xml:space="preserve">décorations de leurs plans & </s> <s xml:id="echoid-s12528" xml:space="preserve">profils.</s> <s xml:id="echoid-s12529" xml:space="preserve"/> </p> <div xml:id="echoid-div615" type="float" level="2" n="5"> <note position="right" xlink:label="note-0577-03" xlink:href="note-0577-03a" xml:space="preserve">Veſtibules <lb/>& corps de <lb/>garde.</note> </div> <p> <s xml:id="echoid-s12530" xml:space="preserve">A droite & </s> <s xml:id="echoid-s12531" xml:space="preserve">à gauche de ce paſſage ſera poſé des bornes de pierre de <lb/> <anchor type="note" xlink:label="note-0577-04a" xlink:href="note-0577-04"/> taille pour empêcher que les moyeux desrouës des voitures n’offen-<lb/>ſent les doſſerets & </s> <s xml:id="echoid-s12532" xml:space="preserve">pieds droits des voûtes, & </s> <s xml:id="echoid-s12533" xml:space="preserve">chacune de ces bornes <lb/>aura cinq pieds & </s> <s xml:id="echoid-s12534" xml:space="preserve">demide hauteur, dont deux pieds & </s> <s xml:id="echoid-s12535" xml:space="preserve">demi ſeront <lb/>enterrés & </s> <s xml:id="echoid-s12536" xml:space="preserve">ſcellés dans un petit maſſif de maçonnerie, dix-huit <pb o="32" file="0578" n="628" rhead="LA SCIENCE DES INGENIEURS,"/> pouces de diamettre au niveau du pavé, & </s> <s xml:id="echoid-s12537" xml:space="preserve">onze à douze à la tête; <lb/></s> <s xml:id="echoid-s12538" xml:space="preserve">ſeront toutes auſſi arondies & </s> <s xml:id="echoid-s12539" xml:space="preserve">piquées proprement à leur place.</s> <s xml:id="echoid-s12540" xml:space="preserve"/> </p> <div xml:id="echoid-div616" type="float" level="2" n="6"> <note position="right" xlink:label="note-0577-04" xlink:href="note-0577-04a" xml:space="preserve">Bornes & <lb/>pavé.</note> </div> <p> <s xml:id="echoid-s12541" xml:space="preserve">Le rez-de-chauſſée, tant du paſſage que des corps de gardes & </s> <s xml:id="echoid-s12542" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0578-01a" xlink:href="note-0578-01"/> veſtibules, ſera pavé avec cailloux poſés dans une forme de ſable <lb/>conditionnée comme il ſera dit ci-après.</s> <s xml:id="echoid-s12543" xml:space="preserve"/> </p> <div xml:id="echoid-div617" type="float" level="2" n="7"> <note position="left" xlink:label="note-0578-01" xlink:href="note-0578-01a" xml:space="preserve">Pavé.</note> </div> <p> <s xml:id="echoid-s12544" xml:space="preserve">Les eſcaliers pour monter ſur le rempart, ſeront conſtruits de la <lb/> <anchor type="note" xlink:label="note-0578-02a" xlink:href="note-0578-02"/> même maniere que ceux des Tours baſtionnées, avec cette diffe-<lb/>rence qu’on pratiquera ſous chacun de ceux-ci une latrine, dans <lb/>laquelle tomberont par un égoût les eaux de la Ville, pour enſuite <lb/>dégorger dans le foſſé. </s> <s xml:id="echoid-s12545" xml:space="preserve">Les murs d’enceinte de ces latrines, de mê-<lb/>me que celui du retour de leur entrée, n’aura qu’un pied & </s> <s xml:id="echoid-s12546" xml:space="preserve">demi <lb/>d’épaiſſeur. </s> <s xml:id="echoid-s12547" xml:space="preserve">Les fermetures, orgues, baſcules, ſeront conſtruites <lb/>ſuivant leurs deſſeins particuliers.</s> <s xml:id="echoid-s12548" xml:space="preserve"/> </p> <div xml:id="echoid-div618" type="float" level="2" n="8"> <note position="left" xlink:label="note-0578-02" xlink:href="note-0578-02a" xml:space="preserve">Eſcaliers <lb/>& latrines.</note> </div> </div> <div xml:id="echoid-div620" type="section" level="1" n="156"> <head xml:id="echoid-head373" xml:space="preserve"><emph style="sc">Logement au dessus</emph>.</head> <p> <s xml:id="echoid-s12549" xml:space="preserve">Les murs de face & </s> <s xml:id="echoid-s12550" xml:space="preserve">de refend, tant du logement au deſſus des <lb/> <anchor type="note" xlink:label="note-0578-03a" xlink:href="note-0578-03"/> veſtibules & </s> <s xml:id="echoid-s12551" xml:space="preserve">corps de garde, que de la chambre des orgues, ſeront <lb/>conſtruits de brique, crépis proprement par dehors, enduits & </s> <s xml:id="echoid-s12552" xml:space="preserve"><lb/>blanchis par dedans, & </s> <s xml:id="echoid-s12553" xml:space="preserve">garnis de pierre de taille dans leurs angles. <lb/></s> <s xml:id="echoid-s12554" xml:space="preserve">Les pieds droits des jambages, portes, croiſées de leurs ſeüils, <lb/>appuis, & </s> <s xml:id="echoid-s12555" xml:space="preserve">fermetures ſeront auſſi de pierres de taille proprement <lb/>apareillées.</s> <s xml:id="echoid-s12556" xml:space="preserve"/> </p> <div xml:id="echoid-div620" type="float" level="2" n="1"> <note position="left" xlink:label="note-0578-03" xlink:href="note-0578-03a" xml:space="preserve">Mur de fa-<lb/>ce & de <lb/>refend.</note> </div> <p> <s xml:id="echoid-s12557" xml:space="preserve">Les cheminées ſeront conſtruites de brique ſur ſix pouces d’é-<lb/> <anchor type="note" xlink:label="note-0578-04a" xlink:href="note-0578-04"/> paiſſeur, elles ſeront enfoncées de trois pouces dans l’épaiſſeur des <lb/>murs de refend & </s> <s xml:id="echoid-s12558" xml:space="preserve">pignon, élevées de trois pieds au deſſus du com-<lb/>ble, & </s> <s xml:id="echoid-s12559" xml:space="preserve">crépies & </s> <s xml:id="echoid-s12560" xml:space="preserve">enduites des deux côtés avec plinte de brique au <lb/>niveau du faîtage, & </s> <s xml:id="echoid-s12561" xml:space="preserve">un autre à trois pieds plus haut à l’endroit de <lb/>la fermeture. </s> <s xml:id="echoid-s12562" xml:space="preserve">Les tuyaux de ces cheminées auront trois pieds de <lb/>longueur dans œuvre, & </s> <s xml:id="echoid-s12563" xml:space="preserve">dix pouces de largeur.</s> <s xml:id="echoid-s12564" xml:space="preserve"/> </p> <div xml:id="echoid-div621" type="float" level="2" n="2"> <note position="left" xlink:label="note-0578-04" xlink:href="note-0578-04a" xml:space="preserve">Cheminées.</note> </div> <p> <s xml:id="echoid-s12565" xml:space="preserve">Les croiſées ſeront faites de bois de chêne bien ſec, leurs chaſſis <lb/> <anchor type="note" xlink:label="note-0578-05a" xlink:href="note-0578-05"/> dormans auront deux pouces d’épaiſſeur, leurs chaſſis à verre un <lb/>pouce & </s> <s xml:id="echoid-s12566" xml:space="preserve">demi, & </s> <s xml:id="echoid-s12567" xml:space="preserve">les volets un pouce, le tout bien aſſemblé à <lb/>raînure & </s> <s xml:id="echoid-s12568" xml:space="preserve">abouëment. </s> <s xml:id="echoid-s12569" xml:space="preserve">Seront de plus garnies de toutes leurs ferru-<lb/>res, ſçavoir ſeize gonds, ſeize fiches à charniere, ſeize targettes <lb/>ovales, & </s> <s xml:id="echoid-s12570" xml:space="preserve">ſeize crampons, le tout proprement limé, & </s> <s xml:id="echoid-s12571" xml:space="preserve">mis en œu-<lb/>vre, les vîtres ſeront de verre blanc, & </s> <s xml:id="echoid-s12572" xml:space="preserve">miſes en plomb de force <lb/>ſuffiſante, puis arrêtées avec trois vergettes bien ſoudées à chaque <lb/>panneau.</s> <s xml:id="echoid-s12573" xml:space="preserve"/> </p> <div xml:id="echoid-div622" type="float" level="2" n="3"> <note position="left" xlink:label="note-0578-05" xlink:href="note-0578-05a" xml:space="preserve">Croiſées de <lb/>menuiſerie.</note> </div> <p> <s xml:id="echoid-s12574" xml:space="preserve">Les portes communes ſeront faites des hauteurs & </s> <s xml:id="echoid-s12575" xml:space="preserve">largeurs des <lb/> <anchor type="note" xlink:label="note-0578-06a" xlink:href="note-0578-06"/> bayes avec bois de chêne bien ſec, d’un pouce & </s> <s xml:id="echoid-s12576" xml:space="preserve">demi d’épaiſſeur, <pb o="33" file="0579" n="629" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> aſſemblées à raînure, collées & </s> <s xml:id="echoid-s12577" xml:space="preserve">emboëtées par les deux bouts de <lb/>ſix pouces de hauteur; </s> <s xml:id="echoid-s12578" xml:space="preserve">ſeront auſſi garnies des gonds en pierre d’un <lb/>pied de long ſur un pouce & </s> <s xml:id="echoid-s12579" xml:space="preserve">demi en quarré, bien ſcellés & </s> <s xml:id="echoid-s12580" xml:space="preserve">coulés <lb/>en plomb, avec penture à queuë d’hironde de deux pouces de lar-<lb/>geur, ſur deux pieds & </s> <s xml:id="echoid-s12581" xml:space="preserve">demi de longueur, attachée auſdites portes <lb/>avec un clou rivé au collet, le tout bruni & </s> <s xml:id="echoid-s12582" xml:space="preserve">bien limé, de même <lb/>que la ſerrure qui ſera à tour & </s> <s xml:id="echoid-s12583" xml:space="preserve">demi avec deux verroüils garnis de <lb/>leurs gâches & </s> <s xml:id="echoid-s12584" xml:space="preserve">de la boule pour les tirer.</s> <s xml:id="echoid-s12585" xml:space="preserve"/> </p> <div xml:id="echoid-div623" type="float" level="2" n="4"> <note position="left" xlink:label="note-0578-06" xlink:href="note-0578-06a" xml:space="preserve">Portes de <lb/>menuiſerie.</note> </div> <p> <s xml:id="echoid-s12586" xml:space="preserve">La partie du plancher dudit bâtiment, qui ſe trouvera au deſſus <lb/> <anchor type="note" xlink:label="note-0579-01a" xlink:href="note-0579-01"/> du veſtibule, portera ſur de petites lambourdes qui ſeront poſées <lb/>au deſſus de la voûte, & </s> <s xml:id="echoid-s12587" xml:space="preserve">l’autre partie ſe trouvant ſur les corps <lb/>de garde qui ne ſont point voûtés, portera ſur des ſolives ſou-<lb/>tenues par des poutres qui auront treize à quinze pouces de gros, <lb/>& </s> <s xml:id="echoid-s12588" xml:space="preserve">les ſolives ſept à cinq; </s> <s xml:id="echoid-s12589" xml:space="preserve">les unes & </s> <s xml:id="echoid-s12590" xml:space="preserve">les autres ſeront des longueurs <lb/>& </s> <s xml:id="echoid-s12591" xml:space="preserve">qualités requiſes, & </s> <s xml:id="echoid-s12592" xml:space="preserve">d’un bon bois de chêne bien équarri à vive <lb/>arête & </s> <s xml:id="echoid-s12593" xml:space="preserve">ſans aubier. </s> <s xml:id="echoid-s12594" xml:space="preserve">Les arbalêtriers du comble, ſes jambes de <lb/>force, entraits, poinçons, blochets, & </s> <s xml:id="echoid-s12595" xml:space="preserve">plattes formes ſeront de mê-<lb/>me bois, le ſurplus de l’aſſemblage ſera de bois de ſapin, & </s> <s xml:id="echoid-s12596" xml:space="preserve">des <lb/>longueurs & </s> <s xml:id="echoid-s12597" xml:space="preserve">groſſeurs dont il ſera donné un détail ci-après. </s> <s xml:id="echoid-s12598" xml:space="preserve">Les <lb/>planchers ſeront auſſi de ſapin, bien dreſſés & </s> <s xml:id="echoid-s12599" xml:space="preserve">bien blanchis, à <lb/>l’exception de ceux qu’on pavera de brique.</s> <s xml:id="echoid-s12600" xml:space="preserve"/> </p> <div xml:id="echoid-div624" type="float" level="2" n="5"> <note position="right" xlink:label="note-0579-01" xlink:href="note-0579-01a" xml:space="preserve">Charbente <lb/>& plancher.</note> </div> <p> <s xml:id="echoid-s12601" xml:space="preserve">La couverture de ces bâtimens ſera faite double, & </s> <s xml:id="echoid-s12602" xml:space="preserve">de tuiles bien <lb/> <anchor type="note" xlink:label="note-0579-02a" xlink:href="note-0579-02"/> cuites du moule ordinaire du pays, poſées ſur un latis deſapin bien <lb/>attaché aux chevrons, & </s> <s xml:id="echoid-s12603" xml:space="preserve">de quatre pouces de pureau. </s> <s xml:id="echoid-s12604" xml:space="preserve">Les égoûts <lb/>y ſeront redoublés, & </s> <s xml:id="echoid-s12605" xml:space="preserve">les faîtieres & </s> <s xml:id="echoid-s12606" xml:space="preserve">arêtieres recouvertes de tui-<lb/>les creuſes, poſées en mortier de chaux & </s> <s xml:id="echoid-s12607" xml:space="preserve">ſable.</s> <s xml:id="echoid-s12608" xml:space="preserve"/> </p> <div xml:id="echoid-div625" type="float" level="2" n="6"> <note position="right" xlink:label="note-0579-02" xlink:href="note-0579-02a" xml:space="preserve">Couvertu-<lb/>re.</note> </div> </div> <div xml:id="echoid-div627" type="section" level="1" n="157"> <head xml:id="echoid-head374" xml:space="preserve"><emph style="sc">Poternes de</emph> <emph style="sc">Sortie</emph>, <emph style="sc">Souterrains, et</emph> <emph style="sc">Aqueducs</emph>.</head> <p> <s xml:id="echoid-s12609" xml:space="preserve">On fondera les pieds droits des poternes de ſortie & </s> <s xml:id="echoid-s12610" xml:space="preserve">des ſouter-<lb/> <anchor type="note" xlink:label="note-0579-03a" xlink:href="note-0579-03"/> rains ou flancs bas, ſur un bon & </s> <s xml:id="echoid-s12611" xml:space="preserve">vif fond avec groſſe maçonnerie <lb/>de même que les eſcaliers pour y deſcendre, puis toute retraite <lb/>faite, on les élevera en parement de brique d’un pied & </s> <s xml:id="echoid-s12612" xml:space="preserve">demi d’é-<lb/>paiſſeur du côté de leur paſſage, & </s> <s xml:id="echoid-s12613" xml:space="preserve">le ſurplus en maçonnerie brute, <lb/>de même que les contreforts, obſervant d’y pratiquer tous les évens <lb/>& </s> <s xml:id="echoid-s12614" xml:space="preserve">cheminées qui ſont marqués ſur le plan. </s> <s xml:id="echoid-s12615" xml:space="preserve">Les voûtes ſeront auſſi <lb/>conſtruites avec briques choiſies ſur trois pieds d’épaiſſeur, puis <lb/>ſeront recouvertes d’une chape de ciment.</s> <s xml:id="echoid-s12616" xml:space="preserve"/> </p> <div xml:id="echoid-div627" type="float" level="2" n="1"> <note position="right" xlink:label="note-0579-03" xlink:href="note-0579-03a" xml:space="preserve">Poternes & <lb/>ſouterrains.</note> </div> <p> <s xml:id="echoid-s12617" xml:space="preserve">Les portes des entrées ſeront depierre de taille toute ſimple & </s> <s xml:id="echoid-s12618" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0579-04a" xlink:href="note-0579-04"/> ſans aucune façon, que celle des feüillures, où ſeront appliquées <lb/>des portes de bois de chêne à deux ventaux de quatre pouces d’é- <pb o="34" file="0580" n="630" rhead="LA SCIENCE DES INGENIEURS,"/> paiſſeur, garnies de quatre gonds, quatre pentures, deux verroüils, <lb/>& </s> <s xml:id="echoid-s12619" xml:space="preserve">deux ſerrures de force ſuffiſante.</s> <s xml:id="echoid-s12620" xml:space="preserve"/> </p> <div xml:id="echoid-div628" type="float" level="2" n="2"> <note position="right" xlink:label="note-0579-04" xlink:href="note-0579-04a" xml:space="preserve">Portes.</note> </div> <p> <s xml:id="echoid-s12621" xml:space="preserve">Les maſſifs, qui porteront les aqueducs, ſeront fondés ſur bon & </s> <s xml:id="echoid-s12622" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0580-01a" xlink:href="note-0580-01"/> vif fond de ſept pieds de largeur, & </s> <s xml:id="echoid-s12623" xml:space="preserve">les pieds droits ſeront revêtus <lb/>par dedans de deux aſſiſes de pierres de taille, d’un pied de hauteur <lb/>chacune, poſées & </s> <s xml:id="echoid-s12624" xml:space="preserve">garnies en ciment, & </s> <s xml:id="echoid-s12625" xml:space="preserve">bien cramponnées avec <lb/>crampons de fer coulés en plomb. </s> <s xml:id="echoid-s12626" xml:space="preserve">Le fond de ces aqueducs ſera <lb/>pavé de pierres de taille à joints recouverts, auſſi poſées en ciment <lb/>ſuivant ſa pente, puis ſera ſurmonté d’une voûte de brique de deux <lb/>pieds d’épaiſſeur terminée pardeſſus en talud, & </s> <s xml:id="echoid-s12627" xml:space="preserve">dont les joints ſe-<lb/>ront bien recirés avant que d’être recouverts de terre; </s> <s xml:id="echoid-s12628" xml:space="preserve">on aura ſoin <lb/>de griller l’entrée de ces aqueducs du côté de la Place, & </s> <s xml:id="echoid-s12629" xml:space="preserve">leur <lb/>ſortie du côté du foſſé, laquelle ſortie ſera réduite à dixpouces de <lb/>largeur ſur un pied de hauteur, avec une gargoüille de pierre de <lb/>taille, qui portera les eaux au de-là du talud du revêtement.</s> <s xml:id="echoid-s12630" xml:space="preserve"/> </p> <div xml:id="echoid-div629" type="float" level="2" n="3"> <note position="left" xlink:label="note-0580-01" xlink:href="note-0580-01a" xml:space="preserve">Aqueducs.</note> </div> </div> <div xml:id="echoid-div631" type="section" level="1" n="158"> <head xml:id="echoid-head375" xml:space="preserve">CONTREGARDES, DEMI-LUNES, TENAILLES, <lb/><emph style="sc">ET</emph> <emph style="sc">Ouvrage a corne</emph>.</head> <p> <s xml:id="echoid-s12631" xml:space="preserve">Lesrevêtemens des contregardes, demi-lunes, tenailles, & </s> <s xml:id="echoid-s12632" xml:space="preserve">ouvra-<lb/> <anchor type="note" xlink:label="note-0580-02a" xlink:href="note-0580-02"/> ge à corne, ſeront fondés auſſi bas que ceux du corps de la Place, <lb/>& </s> <s xml:id="echoid-s12633" xml:space="preserve">avec mêmes materiaux & </s> <s xml:id="echoid-s12634" xml:space="preserve">mêmes précautions, puis ſeront élevés <lb/>comme les courtines, en parement de moëlon piqué, poſé ſur deux <lb/>aſſiſes de pierres de taille ſeulement avec retraite de deux pouces <lb/>par devant, & </s> <s xml:id="echoid-s12635" xml:space="preserve">talud d’un ſixiéme de leur hauteur. </s> <s xml:id="echoid-s12636" xml:space="preserve">Le derriere de <lb/>ce parement ſera élevé à plomb & </s> <s xml:id="echoid-s12637" xml:space="preserve">conſtruit de groſſe maçonnerie <lb/>compoſée comme il eſt dit ci-devant. </s> <s xml:id="echoid-s12638" xml:space="preserve">Puis à la hauteur qui a été <lb/>ſpécifiée en ſon lieu, la maçonnerie ſera arraſée & </s> <s xml:id="echoid-s12639" xml:space="preserve">terminée par <lb/>une aſſiſe de briques poſées de cant & </s> <s xml:id="echoid-s12640" xml:space="preserve">debout, en bonne liaiſon <lb/>& </s> <s xml:id="echoid-s12641" xml:space="preserve">bain de mortier fin. </s> <s xml:id="echoid-s12642" xml:space="preserve">On armera les angles de groſſes pierres de <lb/>taille des meſures & </s> <s xml:id="echoid-s12643" xml:space="preserve">qualités ſuſdites, & </s> <s xml:id="echoid-s12644" xml:space="preserve">on obſervera de pratiquer <lb/>dans les gorges les rempes & </s> <s xml:id="echoid-s12645" xml:space="preserve">eſcaliers déſignés dans le plan, de <lb/>même que l’exacte diſtribution des contreforts qui ſeront auſſi de <lb/>groſſe maçonnerie.</s> <s xml:id="echoid-s12646" xml:space="preserve"/> </p> <div xml:id="echoid-div631" type="float" level="2" n="1"> <note position="left" xlink:label="note-0580-02" xlink:href="note-0580-02a" xml:space="preserve">Revête-<lb/>ment.</note> </div> <p> <s xml:id="echoid-s12647" xml:space="preserve">Les terres des foſſez de ces pieces ſeront portées à la maſſe de <lb/> <anchor type="note" xlink:label="note-0580-03a" xlink:href="note-0580-03"/> leurs remparts & </s> <s xml:id="echoid-s12648" xml:space="preserve">parapets, & </s> <s xml:id="echoid-s12649" xml:space="preserve">employées à les terraſſer; </s> <s xml:id="echoid-s12650" xml:space="preserve">ce qui ſe <lb/>fera par lits battus d’un pied de hauteur, & </s> <s xml:id="echoid-s12651" xml:space="preserve">faſcinés dans le même <lb/>ordre qu’il a été dit pour le corps de la Place.</s> <s xml:id="echoid-s12652" xml:space="preserve"/> </p> <div xml:id="echoid-div632" type="float" level="2" n="2"> <note position="left" xlink:label="note-0580-03" xlink:href="note-0580-03a" xml:space="preserve">Terraſſe-<lb/>ment.</note> </div> <p> <s xml:id="echoid-s12653" xml:space="preserve">A la hauteur du ſommet du revêtement des faces & </s> <s xml:id="echoid-s12654" xml:space="preserve">flancs des <lb/> <anchor type="note" xlink:label="note-0580-04a" xlink:href="note-0580-04"/> ouvrages, & </s> <s xml:id="echoid-s12655" xml:space="preserve">depuis le bord exterieur dudit ſommet, ſera faite une <lb/>berme de dix pieds de largeur aux contregardes, d’un pied & </s> <s xml:id="echoid-s12656" xml:space="preserve">demi <pb o="35" file="0581" n="631" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> aux tenailles, & </s> <s xml:id="echoid-s12657" xml:space="preserve">de dix aux demi-lunes & </s> <s xml:id="echoid-s12658" xml:space="preserve">à l’ouvrage à corne; <lb/></s> <s xml:id="echoid-s12659" xml:space="preserve">le long de laquelle ſera continuée l’élevation des remparts & </s> <s xml:id="echoid-s12660" xml:space="preserve">pa-<lb/>rapets en gazonnage, ou placage ſeulement, obſervant de mettre <lb/>à part toutes les meilleures terresqui ont été portées dans ces pieces <lb/>pour être enſuite paſſées à la claye, & </s> <s xml:id="echoid-s12661" xml:space="preserve">employées tant à la conſtruc-<lb/>tion des parapets, qu’à recouvrir d’un pied & </s> <s xml:id="echoid-s12662" xml:space="preserve">demi de hauteur <lb/>toutes les ſuperficies des terre-plein & </s> <s xml:id="echoid-s12663" xml:space="preserve">talud des remparts, qui <lb/>ſeront, ainſi que les banquettes, bien battus, bien dreſſés, & </s> <s xml:id="echoid-s12664" xml:space="preserve">arraſés <lb/>ſuivant leur niveau & </s> <s xml:id="echoid-s12665" xml:space="preserve">alignement.</s> <s xml:id="echoid-s12666" xml:space="preserve"/> </p> <div xml:id="echoid-div633" type="float" level="2" n="3"> <note position="left" xlink:label="note-0580-04" xlink:href="note-0580-04a" xml:space="preserve">Berme.</note> </div> <p> <s xml:id="echoid-s12667" xml:space="preserve">On plantera ſur ces bermes, à l’exception toutefois de celles des <lb/> <anchor type="note" xlink:label="note-0581-01a" xlink:href="note-0581-01"/> tenailles, une haye vive d’épine blanche, conditionnée comme il <lb/>a été dit ailleurs.</s> <s xml:id="echoid-s12668" xml:space="preserve"/> </p> <div xml:id="echoid-div634" type="float" level="2" n="4"> <note position="right" xlink:label="note-0581-01" xlink:href="note-0581-01a" xml:space="preserve">Haye vive.</note> </div> <p> <s xml:id="echoid-s12669" xml:space="preserve">Les poternes de communication des contregardes aux tenailles <lb/> <anchor type="note" xlink:label="note-0581-02a" xlink:href="note-0581-02"/> ſeront conſtruites dans le même Ordre que celles des courtines, n’y <lb/>ayant de difference que dans leurs dimenſions, qui ont déja été <lb/>expliquées dans leur article.</s> <s xml:id="echoid-s12670" xml:space="preserve"/> </p> <div xml:id="echoid-div635" type="float" level="2" n="5"> <note position="right" xlink:label="note-0581-02" xlink:href="note-0581-02a" xml:space="preserve">Poternes <lb/>des contre-<lb/>gardes.</note> </div> <p> <s xml:id="echoid-s12671" xml:space="preserve">Il ſera fait au paſſage des quatre demi-lunes, qui ſont aux entrées <lb/> <anchor type="note" xlink:label="note-0581-03a" xlink:href="note-0581-03"/> principales de la Place, des portes d’architecture des dimenſions & </s> <s xml:id="echoid-s12672" xml:space="preserve"><lb/>qualités énoncées ci-deſſus; </s> <s xml:id="echoid-s12673" xml:space="preserve">& </s> <s xml:id="echoid-s12674" xml:space="preserve">ces portes ſeront ornées de deux pi-<lb/>laſtres érigés ſuivant les proportions de l’Ordre Toſcan avec leurs <lb/>ſocles, baſes, chapiteaux, architraves, friſes, & </s> <s xml:id="echoid-s12675" xml:space="preserve">corniches, puis ſe-<lb/>ront terminées par un fronton dans lequel ſeront ſculptées les Ar-<lb/>mes du Roi, & </s> <s xml:id="echoid-s12676" xml:space="preserve">ſur lequel ſeront poſées trois boules à feu, montées <lb/>ſur leurs pieds d’eſtaux, garnies de leurs flames, & </s> <s xml:id="echoid-s12677" xml:space="preserve">ſcellées avec <lb/>goujon de fer d’un pied delong coulé en plomb. </s> <s xml:id="echoid-s12678" xml:space="preserve">L’une de ces boules <lb/>ſera miſe ſur le milieu du timpan, & </s> <s xml:id="echoid-s12679" xml:space="preserve">les deux autres ſur les pilaſ-<lb/>tres. </s> <s xml:id="echoid-s12680" xml:space="preserve">Le ſoubaſſement ſera de pierre de taille depuis le deſſus de ſes <lb/>fondemens juſqu’au deſſous du pont-levis, ainſi que tout le com-<lb/>poſé deſdites portes. </s> <s xml:id="echoid-s12681" xml:space="preserve">L’on y obſervera tous les corps & </s> <s xml:id="echoid-s12682" xml:space="preserve">arrieres-corps <lb/>marqués au deſſein, de même que les baſculages & </s> <s xml:id="echoid-s12683" xml:space="preserve">autres aſſorti-<lb/>mens.</s> <s xml:id="echoid-s12684" xml:space="preserve"/> </p> <div xml:id="echoid-div636" type="float" level="2" n="6"> <note position="right" xlink:label="note-0581-03" xlink:href="note-0581-03a" xml:space="preserve">Portes <lb/>d’architec-<lb/>ture.</note> </div> <p> <s xml:id="echoid-s12685" xml:space="preserve">Les fondemens des profils du paſſage, ainſi que leurs contreſorts, <lb/> <anchor type="note" xlink:label="note-0581-04a" xlink:href="note-0581-04"/> ſeront aſſis ſur bon & </s> <s xml:id="echoid-s12686" xml:space="preserve">vif fond, & </s> <s xml:id="echoid-s12687" xml:space="preserve">conſtruits de groſſe maçonnerie; <lb/></s> <s xml:id="echoid-s12688" xml:space="preserve">& </s> <s xml:id="echoid-s12689" xml:space="preserve">après avoir fait les retraites ordinaires au niveau de ce paſſage, <lb/>on commencera l’élevation des murs par deux aſſiſes de pierres de <lb/>taille d’un pied de hauteur chacune, que l’on continuëra enſuite à <lb/>plomb de deux côtés, & </s> <s xml:id="echoid-s12690" xml:space="preserve">en parement de brique d’un pied & </s> <s xml:id="echoid-s12691" xml:space="preserve">demi <lb/>d’épaiſſeur du côté du paſſage; </s> <s xml:id="echoid-s12692" xml:space="preserve">le ſurplus en groſſe maçonnerie <lb/>juſqu’à la hauteur du rempart, au deſſus duquel la maçonnerie des <lb/>parties excedentes ſera faite de brique ſur toute ſon épaiſſeur. </s> <s xml:id="echoid-s12693" xml:space="preserve">Sur <lb/>quoi on obſervera d’arraſer bien de niveau, dès le bas, ladite ma- <pb o="36" file="0582" n="632" rhead="LA SCIENCE DES INGENIEURS,"/> çonnerie à chaque pied & </s> <s xml:id="echoid-s12694" xml:space="preserve">demi de hauteur, & </s> <s xml:id="echoid-s12695" xml:space="preserve">d’y mettre des tra-<lb/>verſes de brique pour faire plus de liaiſon; </s> <s xml:id="echoid-s12696" xml:space="preserve">après quoi on la termi-<lb/>nera à la hauteur du rempart par une aſſiſe auſſi de briques poſées <lb/>de cant & </s> <s xml:id="echoid-s12697" xml:space="preserve">debout en bain de ciment.</s> <s xml:id="echoid-s12698" xml:space="preserve"/> </p> <div xml:id="echoid-div637" type="float" level="2" n="7"> <note position="right" xlink:label="note-0581-04" xlink:href="note-0581-04a" xml:space="preserve">Profils du <lb/>paſſage.</note> </div> </div> <div xml:id="echoid-div639" type="section" level="1" n="159"> <head xml:id="echoid-head376" xml:space="preserve"><emph style="sc">Reduits dans les</emph> <emph style="sc">Demi-lunes</emph>.</head> <p> <s xml:id="echoid-s12699" xml:space="preserve">La conſtruction des reduits ſera conforme en toutes choſes à ce <lb/> <anchor type="note" xlink:label="note-0582-01a" xlink:href="note-0582-01"/> qui a été dit pour celle du corps de la Place; </s> <s xml:id="echoid-s12700" xml:space="preserve">on y obſervera mêmes <lb/>angles, mêmes ſoubaſſemens, mêmes paremens, cordon, garniture, <lb/>& </s> <s xml:id="echoid-s12701" xml:space="preserve">terraſſemens, avec les portes, paſſages, rempes, eſcaliers, & </s> <s xml:id="echoid-s12702" xml:space="preserve">ge-<lb/>neralement tout ce qui eſt exprimé dans leurs plans & </s> <s xml:id="echoid-s12703" xml:space="preserve">profils.</s> <s xml:id="echoid-s12704" xml:space="preserve"/> </p> <div xml:id="echoid-div639" type="float" level="2" n="1"> <note position="left" xlink:label="note-0582-01" xlink:href="note-0582-01a" xml:space="preserve">Reduits.</note> </div> </div> <div xml:id="echoid-div641" type="section" level="1" n="160"> <head xml:id="echoid-head377" xml:space="preserve"><emph style="sc">Revetement des</emph> <emph style="sc">Fossez</emph>.</head> <p> <s xml:id="echoid-s12705" xml:space="preserve">La maçonnerie des revêtemens des foſſez ſera ſemblable à celle <lb/> <anchor type="note" xlink:label="note-0582-02a" xlink:href="note-0582-02"/> des gros revêtemens, & </s> <s xml:id="echoid-s12706" xml:space="preserve">terminée au ſommet par une aſſiſe de bri-<lb/>ques choiſies, poſées de cant & </s> <s xml:id="echoid-s12707" xml:space="preserve">debout en bain de ciment avec un <lb/>pouce de ſaillie ſur le foſſé, & </s> <s xml:id="echoid-s12708" xml:space="preserve">un pouce & </s> <s xml:id="echoid-s12709" xml:space="preserve">demi de pente par deſſus <lb/>vers le même côté. </s> <s xml:id="echoid-s12710" xml:space="preserve">Les angles ſaillans ſeront arondis, & </s> <s xml:id="echoid-s12711" xml:space="preserve">les rentrans <lb/>garnis de pierre de taille ſur deux ou trois pieds de part & </s> <s xml:id="echoid-s12712" xml:space="preserve">d’autre; <lb/></s> <s xml:id="echoid-s12713" xml:space="preserve">obſervant de pratiquer des montées & </s> <s xml:id="echoid-s12714" xml:space="preserve">des deſcentes de trois pieds <lb/>& </s> <s xml:id="echoid-s12715" xml:space="preserve">demi de largeur en rempe d’eſcaliers, dont les marches ſeront <lb/>auſſi de pierres de taille, & </s> <s xml:id="echoid-s12716" xml:space="preserve">d’une ſeule piece, & </s> <s xml:id="echoid-s12717" xml:space="preserve">auront huit pouces <lb/>de hauteur ſur dix de giron, poſées & </s> <s xml:id="echoid-s12718" xml:space="preserve">jointoyées en mortier de ci-<lb/>ment. </s> <s xml:id="echoid-s12719" xml:space="preserve">On aura attention d’augmenter de deux pieds d’épaiſſeur <lb/>de ces revêtements à l’endroit des eſcaliers.</s> <s xml:id="echoid-s12720" xml:space="preserve"/> </p> <div xml:id="echoid-div641" type="float" level="2" n="1"> <note position="left" xlink:label="note-0582-02" xlink:href="note-0582-02a" xml:space="preserve">Revêtement <lb/>des Foſſez</note> </div> </div> <div xml:id="echoid-div643" type="section" level="1" n="161"> <head xml:id="echoid-head378" xml:space="preserve"><emph style="sc">Chemin couvert, et</emph> <emph style="sc">Glacis</emph>.</head> <p> <s xml:id="echoid-s12721" xml:space="preserve">Le parapet des chemins couverts ſera revêtu, comme il a été dit, <lb/> <anchor type="note" xlink:label="note-0582-03a" xlink:href="note-0582-03"/> juſqu’à un pied & </s> <s xml:id="echoid-s12722" xml:space="preserve">demi près de ſon ſommet; </s> <s xml:id="echoid-s12723" xml:space="preserve">ce revêtement ſera fon-<lb/>dé deux pieds plus bas que le deſſus de la banquette, & </s> <s xml:id="echoid-s12724" xml:space="preserve">établi ſur <lb/>deux rangs de madriers de quatre à douze pouces de gros, au deſſus <lb/>deſquels il ſera élevé à plomb juſqu’au niveau de la banquette, <lb/>puis ſuivant le talud du gazon juſqu’à la hauteur de trois pieds & </s> <s xml:id="echoid-s12725" xml:space="preserve">à <lb/>plomb par derriere, le tout en groſſe maçonnerie.</s> <s xml:id="echoid-s12726" xml:space="preserve"/> </p> <div xml:id="echoid-div643" type="float" level="2" n="1"> <note position="left" xlink:label="note-0582-03" xlink:href="note-0582-03a" xml:space="preserve">Chemin <lb/>convert.</note> </div> <p> <s xml:id="echoid-s12727" xml:space="preserve">Le ſurplus de la hauteur ſera gazonné juſqu’au ſommet, & </s> <s xml:id="echoid-s12728" xml:space="preserve">faſ-<lb/> <anchor type="note" xlink:label="note-0582-04a" xlink:href="note-0582-04"/> ciné à l’ordinaire, obſervant d’y employer trois pieds de hau-<lb/>teur de terre douce qu’il faudra étendre juſqu’à cinq toiſes de <lb/>la paliſſade, & </s> <s xml:id="echoid-s12729" xml:space="preserve">bien épierrée, de même que toute la ſurface du gla- <pb o="37" file="0583" n="633" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> cis qu’on aura ſoin de bien unir, & </s> <s xml:id="echoid-s12730" xml:space="preserve">de dreſſer parfaitement ſuivant <lb/>ſa pente.</s> <s xml:id="echoid-s12731" xml:space="preserve"/> </p> <div xml:id="echoid-div644" type="float" level="2" n="2"> <note position="left" xlink:label="note-0582-04" xlink:href="note-0582-04a" xml:space="preserve">Glacis.</note> </div> <p> <s xml:id="echoid-s12732" xml:space="preserve">On élevera l’interieur du parapet des traverſes à même hauteur <lb/> <anchor type="note" xlink:label="note-0583-01a" xlink:href="note-0583-01"/> que celui du chemin couvert, & </s> <s xml:id="echoid-s12733" xml:space="preserve">avec pente d’un pied ou un pied <lb/>& </s> <s xml:id="echoid-s12734" xml:space="preserve">demi du côté de la Place; </s> <s xml:id="echoid-s12735" xml:space="preserve">on le revêtira de maçonnerie comme <lb/>celui du chemin couvert, ou de gazonnage ſeulement, & </s> <s xml:id="echoid-s12736" xml:space="preserve">l’exterieur <lb/>de placage, obſervant auſſi de mettre trois pieds de terre douce <lb/>ſur toute la ſurface ſuperieure de la traverſe, & </s> <s xml:id="echoid-s12737" xml:space="preserve">de la battre par <lb/>lits de ſix pouces, & </s> <s xml:id="echoid-s12738" xml:space="preserve">faſciner de pied en pied. </s> <s xml:id="echoid-s12739" xml:space="preserve">Leurs profils, tant du <lb/>côté du foſſé, que de celui de leur paſſage de communication, ſe-<lb/>ront revêtus ſur toute leur hauteur, & </s> <s xml:id="echoid-s12740" xml:space="preserve">leur ſommet terminé par <lb/>une aſſiſe de briques poſées de cant & </s> <s xml:id="echoid-s12741" xml:space="preserve">debout en mortier de ciment. <lb/></s> <s xml:id="echoid-s12742" xml:space="preserve">Les paſſages de ces traverſes auront chacun quatre pieds & </s> <s xml:id="echoid-s12743" xml:space="preserve">demi <lb/>de largeur priſe dans l’épaiſſeur du glacis, & </s> <s xml:id="echoid-s12744" xml:space="preserve">une toiſe de retour <lb/>pour ſe couvrir des enfilades. </s> <s xml:id="echoid-s12745" xml:space="preserve">Les banquettes ſeront ſemblables à <lb/>celles des chemins couverts.</s> <s xml:id="echoid-s12746" xml:space="preserve"/> </p> <div xml:id="echoid-div645" type="float" level="2" n="3"> <note position="right" xlink:label="note-0583-01" xlink:href="note-0583-01a" xml:space="preserve">Traverſes.</note> </div> <p> <s xml:id="echoid-s12747" xml:space="preserve">On revêtira auſſi à même hauteur que celle des revêtemens des <lb/> <anchor type="note" xlink:label="note-0583-02a" xlink:href="note-0583-02"/> chemins couverts, tous les profils des ſorties & </s> <s xml:id="echoid-s12748" xml:space="preserve">paſſages des barrie-<lb/>res. </s> <s xml:id="echoid-s12749" xml:space="preserve">A l’égard de ceux qui ſe trouveront vis-à-vis les entrées des <lb/>quatre grandes portes de la Place, on les revêtira d’un mur de bri-<lb/>que de deux pieds neuf pouces d’épaiſſeur du côté du chemin cou-<lb/>vert, & </s> <s xml:id="echoid-s12750" xml:space="preserve">de deux pieds trois pouces à ſon autre extremité du côté <lb/>du glacis, avec talud & </s> <s xml:id="echoid-s12751" xml:space="preserve">retraite en ſaillie de trois pouces pour les <lb/>fondemens. </s> <s xml:id="echoid-s12752" xml:space="preserve">Ce mur ſera élevé à la hauteur du glacis dont il ſuivra <lb/>la pente & </s> <s xml:id="echoid-s12753" xml:space="preserve">ſon ſommet terminé par une aſſiſe de briques poſées de <lb/>cant & </s> <s xml:id="echoid-s12754" xml:space="preserve">debout en bain de ciment.</s> <s xml:id="echoid-s12755" xml:space="preserve"/> </p> <div xml:id="echoid-div646" type="float" level="2" n="4"> <note position="right" xlink:label="note-0583-02" xlink:href="note-0583-02a" xml:space="preserve">Profils des <lb/>paſſages des <lb/>barrieres.</note> </div> <p> <s xml:id="echoid-s12756" xml:space="preserve">Les paliſſades du chemin couvert des traverſes ſeront faites de <lb/> <anchor type="note" xlink:label="note-0583-03a" xlink:href="note-0583-03"/> bois de chêne, & </s> <s xml:id="echoid-s12757" xml:space="preserve">auront huit pieds de hauteur ſur dix-huit à vingt <lb/>pouces de tour, on les eſpacera de deux doigts marqués ſur leur lit-<lb/>teau, l’une de l’autre, après les avoir bien appointées.</s> <s xml:id="echoid-s12758" xml:space="preserve"/> </p> <div xml:id="echoid-div647" type="float" level="2" n="5"> <note position="right" xlink:label="note-0583-03" xlink:href="note-0583-03a" xml:space="preserve">Paliſſades.</note> </div> <p> <s xml:id="echoid-s12759" xml:space="preserve">Pour fermer les paſſages & </s> <s xml:id="echoid-s12760" xml:space="preserve">ſorties du chemin couvert, ſera fait des <lb/> <anchor type="note" xlink:label="note-0583-04a" xlink:href="note-0583-04"/> barrieres de la longueur des paſſages, à deux ventaux tournans ſur pi-<lb/>vots, arrêtés par le haut avec des collets & </s> <s xml:id="echoid-s12761" xml:space="preserve">aſſemblés par des traver-<lb/>ſes & </s> <s xml:id="echoid-s12762" xml:space="preserve">contre-fiches. </s> <s xml:id="echoid-s12763" xml:space="preserve">Ces barrieres ſeront entretenuës par des poteaux <lb/>de dix à onze pouces de gros, & </s> <s xml:id="echoid-s12764" xml:space="preserve">neuf pieds & </s> <s xml:id="echoid-s12765" xml:space="preserve">demi de longueur, <lb/>ayant la pointe à même hauteur que celle des paliſſades, tenus en rai-<lb/>ſon chacun par un patin de ſept pieds de long, & </s> <s xml:id="echoid-s12766" xml:space="preserve">ſept à huit pouces <lb/>de gros, & </s> <s xml:id="echoid-s12767" xml:space="preserve">aſſemblés par deux ſeüils de la longeur des bayes, & </s> <s xml:id="echoid-s12768" xml:space="preserve"><lb/>de neuf à dix pouces de groſſeur, dont l’un ſera enterré de deux à <lb/>trois pieds, & </s> <s xml:id="echoid-s12769" xml:space="preserve">l’autre poſé au niveau du paſſage; </s> <s xml:id="echoid-s12770" xml:space="preserve">le tout de bois de <lb/>chêne conditionné comme il eſt dit en ſon lieu, & </s> <s xml:id="echoid-s12771" xml:space="preserve">garni de ſes fer-<lb/>rures & </s> <s xml:id="echoid-s12772" xml:space="preserve">ſerrures de force convenable.</s> <s xml:id="echoid-s12773" xml:space="preserve"/> </p> <div xml:id="echoid-div648" type="float" level="2" n="6"> <note position="right" xlink:label="note-0583-04" xlink:href="note-0583-04a" xml:space="preserve">Grandes <lb/>barrieres.</note> </div> <pb o="38" file="0584" n="634" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s12774" xml:space="preserve">Il ſera auſſi poſé de petites barrieres à un ſeul ventail de quatre <lb/> <anchor type="note" xlink:label="note-0584-01a" xlink:href="note-0584-01"/> pieds & </s> <s xml:id="echoid-s12775" xml:space="preserve">demi de largeur à l’entrée des paſſages de chaque traverſe, <lb/>& </s> <s xml:id="echoid-s12776" xml:space="preserve">ſeront des mêmes hauteurs, bois, aſſemblages, & </s> <s xml:id="echoid-s12777" xml:space="preserve">ferrures, que <lb/>les précedens, à l’exception des poteaux qui n’auront que neuf à <lb/>dix pouces de groſſeur.</s> <s xml:id="echoid-s12778" xml:space="preserve"/> </p> <div xml:id="echoid-div649" type="float" level="2" n="7"> <note position="left" xlink:label="note-0584-01" xlink:href="note-0584-01a" xml:space="preserve">Petites <lb/>barrieres.</note> </div> </div> <div xml:id="echoid-div651" type="section" level="1" n="162"> <head xml:id="echoid-head379" xml:space="preserve"> <emph style="sc">Ponts de la</emph> <emph style="sc">Place</emph> </head> <p> <s xml:id="echoid-s12779" xml:space="preserve">Les ponts dormans des entrées principales de la Place, tant ſur <lb/> <anchor type="note" xlink:label="note-0584-02a" xlink:href="note-0584-02"/> le grand foſſé, que ſur celui des demi-lunes & </s> <s xml:id="echoid-s12780" xml:space="preserve">reduits, porteront <lb/>ſur des fermes eſpacées à douze pieds de diſtance l’une de l’autre <lb/>de milieu en milieu, & </s> <s xml:id="echoid-s12781" xml:space="preserve">chacune de ces fermes ſur une pile de ma-<lb/>çonnerie de pierre de taille d’un pied de hauteur & </s> <s xml:id="echoid-s12782" xml:space="preserve">d’un & </s> <s xml:id="echoid-s12783" xml:space="preserve">demi de <lb/>largeur, qui ſaillira hors du nud des ſeüils, & </s> <s xml:id="echoid-s12784" xml:space="preserve">ſera érigé au deſſus <lb/>d’un maſſif de groſſe maçonnerie fondé ſur des madriers de chêne.</s> <s xml:id="echoid-s12785" xml:space="preserve"/> </p> <div xml:id="echoid-div651" type="float" level="2" n="1"> <note position="left" xlink:label="note-0584-02" xlink:href="note-0584-02a" xml:space="preserve">Ponts-dor-<lb/>mans des <lb/>entrées <lb/>principales.</note> </div> <p> <s xml:id="echoid-s12786" xml:space="preserve">Ces fermes ſeront compoſées de cinq poteaux, chacun de douze <lb/>à quatorze pouces de groſſeur, dont un ſera poſé dans le milieu & </s> <s xml:id="echoid-s12787" xml:space="preserve"><lb/>à plomb, & </s> <s xml:id="echoid-s12788" xml:space="preserve">deux autres de chaque côté en talud avec des contre-<lb/>fiches & </s> <s xml:id="echoid-s12789" xml:space="preserve">liens de neuf à dix pouces, le tout aſſemblé à tenons & </s> <s xml:id="echoid-s12790" xml:space="preserve"><lb/>mortoiſes avec renfort dans le ſeüil & </s> <s xml:id="echoid-s12791" xml:space="preserve">dans le chapeau.</s> <s xml:id="echoid-s12792" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12793" xml:space="preserve">On poſera ſur chaque travée cinq poutrelles de treize pieds de <lb/>longueur chacune, & </s> <s xml:id="echoid-s12794" xml:space="preserve">de douze à treize pouces de groſſeur, qu’on aura <lb/>ſoin d’eſpacer également ſur quinze pieds de largeur qui ſera celle <lb/>de ces ponts, puis on les couvrira en travers d’un couchis de ma-<lb/>driers de chêne de ſeize pieds de longueur & </s> <s xml:id="echoid-s12795" xml:space="preserve">de quatre pouces d’é-<lb/>paiſſeur ſeulement, ſur le milieu deſquels ſera fait en redoublement <lb/>d’autres madriers de même bois de dix pieds de longueur, & </s> <s xml:id="echoid-s12796" xml:space="preserve">detrois <lb/>pouces d’épaiſſeur, pour garantir le premier plancher de l’effort & </s> <s xml:id="echoid-s12797" xml:space="preserve"><lb/>frottement des voitures.</s> <s xml:id="echoid-s12798" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12799" xml:space="preserve">Les poteaux des appuis ſeront enſuite dreſſés ſur les chapeaux, <lb/>& </s> <s xml:id="echoid-s12800" xml:space="preserve">auront chacun ſix pieds de long, & </s> <s xml:id="echoid-s12801" xml:space="preserve">ſept à huit pouces de gros; <lb/></s> <s xml:id="echoid-s12802" xml:space="preserve">ils ſeront garnis de leurs liens pendans, appuis, ſous-appuis, pote-<lb/>lets, & </s> <s xml:id="echoid-s12803" xml:space="preserve">croix de ſaint André. </s> <s xml:id="echoid-s12804" xml:space="preserve">Les liens pendans auront chacun ſix pieds <lb/>de longueur ſur ſix à douze de groſſeur; </s> <s xml:id="echoid-s12805" xml:space="preserve">les appuis & </s> <s xml:id="echoid-s12806" xml:space="preserve">ſous-appuis <lb/>chacun douze pieds de long, & </s> <s xml:id="echoid-s12807" xml:space="preserve">ſix à ſix de gros; </s> <s xml:id="echoid-s12808" xml:space="preserve">les poetlets cha-<lb/>cun trois pieds de long ſur cinq à ſix de gros, & </s> <s xml:id="echoid-s12809" xml:space="preserve">les croix de ſaint <lb/>André ſix pieds de long ſur cinq à ſix de gros. </s> <s xml:id="echoid-s12810" xml:space="preserve">Si l’on pavoit ces <lb/>ponts, le garde pavé aura neuf à neuf pouces d’épaiſſeur ſur toute <lb/>la longueur des ponts.</s> <s xml:id="echoid-s12811" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12812" xml:space="preserve">Les ponts-levis ſeront faits de longueur & </s> <s xml:id="echoid-s12813" xml:space="preserve">ouverture des portes <lb/> <anchor type="note" xlink:label="note-0584-03a" xlink:href="note-0584-03"/> de la Place, & </s> <s xml:id="echoid-s12814" xml:space="preserve">ſeront aſſortis de leurs fléches, baſcules, chaſſis, <pb o="39" file="0585" n="635" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> entre-toiſes, chaînes, ſerrures, & </s> <s xml:id="echoid-s12815" xml:space="preserve">ferrures néceſſaires, le tout bien <lb/>arrêté & </s> <s xml:id="echoid-s12816" xml:space="preserve">attaché avec boulons, vis, & </s> <s xml:id="echoid-s12817" xml:space="preserve">écrou proprement enchaſſés <lb/>& </s> <s xml:id="echoid-s12818" xml:space="preserve">mis en œuvre conformement aux deſſeins qui en ſeront donnés. <lb/></s> <s xml:id="echoid-s12819" xml:space="preserve">Obſervant en general de donner vingt-ſept pieds de longueur aux <lb/>fleches ſur douze & </s> <s xml:id="echoid-s12820" xml:space="preserve">quatorze pouces de groſſeur par le gros bout, <lb/>& </s> <s xml:id="echoid-s12821" xml:space="preserve">neuf à dix par le petit; </s> <s xml:id="echoid-s12822" xml:space="preserve">reglant au ſurplus leurs aſſemblages ſe-<lb/>lon les calibres néceſſaires pour lever le marche-pied de ces ponts, <lb/>dont il n’y doit avoir que le chaſſis de bois de chêne, & </s> <s xml:id="echoid-s12823" xml:space="preserve">le reſte de <lb/>bois de ſapin pour être plus leger & </s> <s xml:id="echoid-s12824" xml:space="preserve">plus facile à lever & </s> <s xml:id="echoid-s12825" xml:space="preserve">à mouvoir.</s> <s xml:id="echoid-s12826" xml:space="preserve"/> </p> <div xml:id="echoid-div652" type="float" level="2" n="2"> <note position="left" xlink:label="note-0584-03" xlink:href="note-0584-03a" xml:space="preserve">Ponts-le-<lb/>vis.</note> </div> <p> <s xml:id="echoid-s12827" xml:space="preserve">Les ponts de communication des contregardes aux tenailles ſe-<lb/> <anchor type="note" xlink:label="note-0585-01a" xlink:href="note-0585-01"/> ront plus legers que les précedens, & </s> <s xml:id="echoid-s12828" xml:space="preserve">conſiſteront ſeulement en <lb/>trois fermes eſpacées à dix pieds neuf pouces de diſtance les unes <lb/>des autres de milieu en milieu, dont chacune ſera compoſée d’un <lb/>ſeüil, d’un chapeau, de deux montans, & </s> <s xml:id="echoid-s12829" xml:space="preserve">des liens néceſſaires. </s> <s xml:id="echoid-s12830" xml:space="preserve">Les <lb/>ſeüils auront dix pieds onze pouces de long ſur ſept à huit pouces <lb/>de gros; </s> <s xml:id="echoid-s12831" xml:space="preserve">les poteaux ſept pieds cinq pouces de longueur entre ſeüil <lb/>& </s> <s xml:id="echoid-s12832" xml:space="preserve">chapeau, ſur ſept à ſept de groſſeur; </s> <s xml:id="echoid-s12833" xml:space="preserve">les chapeaux ſix pieds trois <lb/>pouces de long ſur ſept à ſept; </s> <s xml:id="echoid-s12834" xml:space="preserve">les liens trois pieds ſur ſix à ſix; <lb/></s> <s xml:id="echoid-s12835" xml:space="preserve">les poutrelles vingt-quatre pieds & </s> <s xml:id="echoid-s12836" xml:space="preserve">demi ſur ſix à ſept, & </s> <s xml:id="echoid-s12837" xml:space="preserve">les ma-<lb/>driers du plancher quatre pouces d’épaiſſeur. </s> <s xml:id="echoid-s12838" xml:space="preserve">Leſdites fermes ſe-<lb/>ront auſſi poſées ſur un maſſif de maçonnerie, & </s> <s xml:id="echoid-s12839" xml:space="preserve">le pont-levis ſera <lb/>de la grandeur de l’ouverture de la porte du ſouterrain avec des <lb/>groſſeurs proportionnées.</s> <s xml:id="echoid-s12840" xml:space="preserve"/> </p> <div xml:id="echoid-div653" type="float" level="2" n="3"> <note position="right" xlink:label="note-0585-01" xlink:href="note-0585-01a" xml:space="preserve">Ponts de <lb/>communi-<lb/>cation des <lb/>contregar-<lb/>des aux te-<lb/>nailles.</note> </div> </div> <div xml:id="echoid-div655" type="section" level="1" n="163"> <head xml:id="echoid-head380" xml:space="preserve"><emph style="sc">Guerites</emph>.</head> <p> <s xml:id="echoid-s12841" xml:space="preserve">Les guerites de pierre de taille ſe feront à chaque angle flanqué <lb/> <anchor type="note" xlink:label="note-0585-02a" xlink:href="note-0585-02"/> des Tours baſtionnées, de même qu’au milieu de chaque courtine, <lb/>ſeront de figure pentagonale, & </s> <s xml:id="echoid-s12842" xml:space="preserve">auront quatre pieds & </s> <s xml:id="echoid-s12843" xml:space="preserve">demi de <lb/>diametre dans œuvre, & </s> <s xml:id="echoid-s12844" xml:space="preserve">huit pouces d’épaiſſeur de parpin. </s> <s xml:id="echoid-s12845" xml:space="preserve">On pra-<lb/>tiquera à leur entrée une porte de deux pieds de largeur ſur ſix de <lb/>hauteur, & </s> <s xml:id="echoid-s12846" xml:space="preserve">à chacune de leurs faces un petit creneau de deux <lb/>pieds de hauteur & </s> <s xml:id="echoid-s12847" xml:space="preserve">de ſix pouces de largeur dans le milieu de ſon <lb/>épaiſſeur, faiſant dedans & </s> <s xml:id="echoid-s12848" xml:space="preserve">dehors un ébraſement de trois pouces <lb/>de chaque côté de ce creneau. </s> <s xml:id="echoid-s12849" xml:space="preserve">On obſervera d’ailleurs tous les pan-<lb/>neaux, boſſages, cordons, & </s> <s xml:id="echoid-s12850" xml:space="preserve">ornemens qui ſont marqués dans le <lb/>deſſein. </s> <s xml:id="echoid-s12851" xml:space="preserve">Ces guerites ſeront poſées ſur un cul de lampe auſſi de pierres <lb/>de taille, dans la face duquel ſeront proprement ſculptées les Ar-<lb/>mes du Roy, puis elles ſeront ſurmontées d’une voûte en dôme <lb/>taillées & </s> <s xml:id="echoid-s12852" xml:space="preserve">poſées à joints recouverts par aſſiſes égales, bien travaillées <lb/>& </s> <s xml:id="echoid-s12853" xml:space="preserve">miſes en mortier de ciment. </s> <s xml:id="echoid-s12854" xml:space="preserve">Au deſſus du dôme ſera élevée une <pb o="40" file="0586" n="636" rhead="LA SCIENCE DES INGENIEURS,"/> fleur de lys de même pierre, arrêtée ſur ſon pied d’eſtal avec un <lb/>goujon de fer d’un pied de longueur, bien ſcellée en plomb.</s> <s xml:id="echoid-s12855" xml:space="preserve"/> </p> <div xml:id="echoid-div655" type="float" level="2" n="1"> <note position="right" xlink:label="note-0585-02" xlink:href="note-0585-02a" xml:space="preserve">Guerites <lb/>de pierre de <lb/>taille.</note> </div> <p> <s xml:id="echoid-s12856" xml:space="preserve">On communiquera à ces guerites par un paſſage de deux pieds & </s> <s xml:id="echoid-s12857" xml:space="preserve"><lb/> <anchor type="note" xlink:label="note-0586-01a" xlink:href="note-0586-01"/> demi à trois pieds de largeur, revêtu de chaque côté d’un mur de <lb/>brique d’un pied & </s> <s xml:id="echoid-s12858" xml:space="preserve">demi d’épaiſſeur qui profilera les parapets & </s> <s xml:id="echoid-s12859" xml:space="preserve"><lb/>banquettes.</s> <s xml:id="echoid-s12860" xml:space="preserve"/> </p> <div xml:id="echoid-div656" type="float" level="2" n="2"> <note position="left" xlink:label="note-0586-01" xlink:href="note-0586-01a" xml:space="preserve">Paſſage des <lb/>Guerites,</note> </div> <p> <s xml:id="echoid-s12861" xml:space="preserve">Toutes les autres guerites, tant des contregardes que des demi-<lb/> <anchor type="note" xlink:label="note-0586-02a" xlink:href="note-0586-02"/> lunes, ouvrages à corne, & </s> <s xml:id="echoid-s12862" xml:space="preserve">autres de la Place, où il en ſera beſoin, <lb/>ſeront de charpente de bois de chêne, & </s> <s xml:id="echoid-s12863" xml:space="preserve">auront deux pieds & </s> <s xml:id="echoid-s12864" xml:space="preserve">de-<lb/>mi de largeur en quarré dans œuvre, ſur cinq pieds huit pouces de <lb/>hauteur, non compriſe ſa couverture. </s> <s xml:id="echoid-s12865" xml:space="preserve">Les bois des montans & </s> <s xml:id="echoid-s12866" xml:space="preserve">en-<lb/>tre-toiſes auront ſix pouces de gros, & </s> <s xml:id="echoid-s12867" xml:space="preserve">le chaſſis d’en bas ſept à huit. <lb/></s> <s xml:id="echoid-s12868" xml:space="preserve">Elles ſeront recouvertes, par les flancs & </s> <s xml:id="echoid-s12869" xml:space="preserve">par le deſſus, de planches <lb/>de ſapin bien attachées, & </s> <s xml:id="echoid-s12870" xml:space="preserve">ſeront percées de crenaux par les côtés.</s> <s xml:id="echoid-s12871" xml:space="preserve"/> </p> <div xml:id="echoid-div657" type="float" level="2" n="3"> <note position="left" xlink:label="note-0586-02" xlink:href="note-0586-02a" xml:space="preserve">Guerites <lb/>de bois.</note> </div> </div> <div xml:id="echoid-div659" type="section" level="1" n="164"> <head xml:id="echoid-head381" xml:space="preserve"><emph style="sc">Puits</emph>.</head> <p> <s xml:id="echoid-s12872" xml:space="preserve">Les puits de la Place ſeront approfondis juſqu’à ce qu’ily ait qua-<lb/> <anchor type="note" xlink:label="note-0586-03a" xlink:href="note-0586-03"/> tre à cinq pieds d’eau vive, & </s> <s xml:id="echoid-s12873" xml:space="preserve">plus, s’il eſt poſſible, après quoi on <lb/>placera dans le fond un roüet de bois de chêne de quatre à douze <lb/>pouces de groſſeur, & </s> <s xml:id="echoid-s12874" xml:space="preserve">de quatre pieds de diametre dans œuvre, <lb/>ſur lequel ſeront poſés quatre aſſiſes de pierres de taille l’un ſur <lb/>l’autre, d’un pied de hauteur chacune, faiſant parpin de dix-huit <lb/>pouces d’épaiſſeur, taillées dedans & </s> <s xml:id="echoid-s12875" xml:space="preserve">dehors, poſées en ciment & </s> <s xml:id="echoid-s12876" xml:space="preserve"><lb/>bien cramponées avec crampons de fer coulés en plomb. </s> <s xml:id="echoid-s12877" xml:space="preserve">Le ſurplus <lb/>ſera élevé en maçonnerie de brique ou de moëlon, faite avec un <lb/>mortier de chaux & </s> <s xml:id="echoid-s12878" xml:space="preserve">ſable juſqu’à trois pouces près de la hauteur,<unsure/> <lb/>du rez-de-chauſſée de la Place, puis ſera ſurmonté de trois autres <lb/>aſſiſes auſſi de pierre de taille d’un pied de hauteur chacune, fai-<lb/>ſant parpin & </s> <s xml:id="echoid-s12879" xml:space="preserve">proprement taillées dedans & </s> <s xml:id="echoid-s12880" xml:space="preserve">dehors, la derniere <lb/>deſquelles ſervira de margelle, & </s> <s xml:id="echoid-s12881" xml:space="preserve">ces trois aſſiſes ſeront poſées en <lb/>ciment, & </s> <s xml:id="echoid-s12882" xml:space="preserve">cramponées comme il vient d’être dit; </s> <s xml:id="echoid-s12883" xml:space="preserve">au ſurplus, les <lb/>puits ſeront garnis de leurs chaînes, poulies, ſeaux, & </s> <s xml:id="echoid-s12884" xml:space="preserve">aſſemblage <lb/>de charpente néceſſaire, tant pour le ſuport des poulies, que pour <lb/>la couverture, s’il en eſt beſoin.</s> <s xml:id="echoid-s12885" xml:space="preserve"/> </p> <div xml:id="echoid-div659" type="float" level="2" n="1"> <note position="left" xlink:label="note-0586-03" xlink:href="note-0586-03a" xml:space="preserve">Puits.</note> </div> </div> <div xml:id="echoid-div661" type="section" level="1" n="165"> <head xml:id="echoid-head382" xml:space="preserve"><emph style="sc">Pave’ de la</emph> <emph style="sc">Place</emph>.</head> <p> <s xml:id="echoid-s12886" xml:space="preserve">Le pavé de la grande Place ſera conſtruit de plus gros cailloux <lb/> <anchor type="note" xlink:label="note-0586-04a" xlink:href="note-0586-04"/> que l’on pourra trouver, & </s> <s xml:id="echoid-s12887" xml:space="preserve">ſera conduit régulierement ſur une <lb/>pente égale pour faciliter l’écoulement des eaux; </s> <s xml:id="echoid-s12888" xml:space="preserve">on élevera pour <pb file="0587" n="637"/> <pb file="0587a" n="638"/> <anchor type="figure" xlink:label="fig-0587a-01a" xlink:href="fig-0587a-01"/> <pb file="0588" n="639"/> <anchor type="figure" xlink:label="fig-0588-01a" xlink:href="fig-0588-01"/> <pb file="0589" n="640"/> <pb file="0589a" n="641"/> <anchor type="figure" xlink:label="fig-0589a-01a" xlink:href="fig-0589a-01"/> <pb file="0590" n="642"/> <pb o="41" file="0591" n="643" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> cet effet le centre de la Place de quatre pieds, comme il a été dit, <lb/>ce qui reviendra à trois ou quatre lignes par toiſe ou environ: </s> <s xml:id="echoid-s12889" xml:space="preserve">& </s> <s xml:id="echoid-s12890" xml:space="preserve"><lb/>on obſervera, non ſeulement de placer les ruiſſeaux dans le milieu <lb/>des ruës avec pentes d’envion deux pouces & </s> <s xml:id="echoid-s12891" xml:space="preserve">demi par toiſe, à <lb/>commencer du pied des maiſons juſqu’auſdits ruiſſeaux; </s> <s xml:id="echoid-s12892" xml:space="preserve">mais en-<lb/>core de diriger les pentes de longueur ſuivant la pente generale qu’il <lb/>y aura depuis le centre de la Place juſqu’aux remparts. </s> <s xml:id="echoid-s12893" xml:space="preserve">Ce pavé <lb/>ſera ſur une forme de ſable de huit pouces de hauteur à petits joints <lb/>& </s> <s xml:id="echoid-s12894" xml:space="preserve">en bonne liaiſon, puis ſera bien battu & </s> <s xml:id="echoid-s12895" xml:space="preserve">dreſſé avec la damoi-<lb/>ſelle le plus uniment que faire ſe pourra.</s> <s xml:id="echoid-s12896" xml:space="preserve"/> </p> <div xml:id="echoid-div661" type="float" level="2" n="1"> <note position="left" xlink:label="note-0586-04" xlink:href="note-0586-04a" xml:space="preserve">Pavé.</note> <figure xlink:label="fig-0587a-01" xlink:href="fig-0587a-01a"> <image file="0587a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0587a-01"/> </figure> <figure xlink:label="fig-0588-01" xlink:href="fig-0588-01a"> <image file="0588-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0588-01"/> </figure> <figure xlink:label="fig-0589a-01" xlink:href="fig-0589a-01a"> <image file="0589a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0589a-01"/> </figure> </div> <p> <s xml:id="echoid-s12897" xml:space="preserve">Voilà à peu près tout ce qui concerne la conſtruction d’une Place <lb/>neuve, & </s> <s xml:id="echoid-s12898" xml:space="preserve">l’arrangement qu’on doit obſerver dans ſon Devis. </s> <s xml:id="echoid-s12899" xml:space="preserve">S’il ſe <lb/>trouvoit d’ailleurs des pilotages, écluſes & </s> <s xml:id="echoid-s12900" xml:space="preserve">autres ouvrages à faire <lb/>dont il n’a pas été parlé, parce que nous nous propoſons d’en faire <lb/>le détail dans l’Architecture hydraulique, il faudroit les y inſerer, <lb/>n’ayant mis ici préciſement que ce qui a rapport au Neuf-Briſac, <lb/>dont j’ai tâché de ne rien omettre, tant pour ce qui regarde la <lb/>diſtribution des parties, que l’ordre de l’execution. </s> <s xml:id="echoid-s12901" xml:space="preserve">Je n’y ai point <lb/>parlé non plus des magazins à poudre ordinaires, parce que leur <lb/>conſtruction a été ſuffiſamment traitée dans le quatriéme Livre.</s> <s xml:id="echoid-s12902" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12903" xml:space="preserve">A l’égard des Devis qui ſe font annuellement pour l’entretien ou <lb/>la réparation des Places, on ſuit communement l’ordre des articles <lb/>de l’état de la Cour, & </s> <s xml:id="echoid-s12904" xml:space="preserve">on traite chaque article en particulier & </s> <s xml:id="echoid-s12905" xml:space="preserve"><lb/>définitivement, ſans s’aſſujettir aux diviſions que j’ai obſervées dans <lb/>le Devis précédent, qui n’ont lieu que dans les ouvrages de conſe-<lb/>quence. </s> <s xml:id="echoid-s12906" xml:space="preserve">Cependant, s’il ſe trouve dans les Devis annuels quelque <lb/>choſe de neuf à conſtruire, & </s> <s xml:id="echoid-s12907" xml:space="preserve">qui demande une attention particu-<lb/>liere, il ſera bon d’en faire un article détaillé, conformement au <lb/>modele ci-deſſus, & </s> <s xml:id="echoid-s12908" xml:space="preserve">d’y obſerver toutes les conditions & </s> <s xml:id="echoid-s12909" xml:space="preserve">formalités <lb/>juſques dans les moindres circonſtances.</s> <s xml:id="echoid-s12910" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div663" type="section" level="1" n="166"> <head xml:id="echoid-head383" xml:space="preserve">CONDITIONS ELEMENTAIRES DU DEVIS <lb/>d’un Bâtiment civil.</head> <head xml:id="echoid-head384" xml:space="preserve"><emph style="sc">De’blais des</emph> <emph style="sc">Terres</emph>.</head> <p> <s xml:id="echoid-s12911" xml:space="preserve">A Près avoir tracé les murs du Bâtiment, & </s> <s xml:id="echoid-s12912" xml:space="preserve">rectifié ſon aligne-<lb/>ment, il ſera fait le déblais des terres des fondemens ſur en-<lb/>viron quatre pieds de largeur par le haut, & </s> <s xml:id="echoid-s12913" xml:space="preserve">trois par le bas, juſ-<lb/>qu’à ce qu’on ait trouvé un fond ferme & </s> <s xml:id="echoid-s12914" xml:space="preserve">ſolide, lequel ſera en- <pb o="42" file="0592" n="644" rhead="LA SCIENCE DES INGENIEURS,"/> ſuite dreſſé bien de niveau dans toute ſon étenduë, & </s> <s xml:id="echoid-s12915" xml:space="preserve">aſſuré, s’il <lb/>eſt beſoin, par des madriers de trois à quatre pouces d’épaiſſeur.</s> <s xml:id="echoid-s12916" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div664" type="section" level="1" n="167"> <head xml:id="echoid-head385" xml:space="preserve"><emph style="sc">Maçonnerie</emph>.</head> <p> <s xml:id="echoid-s12917" xml:space="preserve">Les fondemens des murs de face auront deux pieds & </s> <s xml:id="echoid-s12918" xml:space="preserve">demi d’é-<lb/>paiſſeur, & </s> <s xml:id="echoid-s12919" xml:space="preserve">ſeront non bloqués contre les terres, mais élevés à plomb <lb/>& </s> <s xml:id="echoid-s12920" xml:space="preserve">parallelement entre deux lignes, faiſant parement de chaque cô-<lb/>té, puis ſeront bien garnis & </s> <s xml:id="echoid-s12921" xml:space="preserve">arraſés de niveau, le tout poſé en <lb/>bonne liaiſon, & </s> <s xml:id="echoid-s12922" xml:space="preserve">maçonné avec bon moëlon & </s> <s xml:id="echoid-s12923" xml:space="preserve">mortier compoſé <lb/>d’un tiers de chaux meſurée vive, & </s> <s xml:id="echoid-s12924" xml:space="preserve">de deux tiers de ſable; </s> <s xml:id="echoid-s12925" xml:space="preserve">au <lb/>deſſus de ces fondemens & </s> <s xml:id="echoid-s12926" xml:space="preserve">avec même materiaux on érigera les <lb/>murs des faces ſur deux pieds d’épaiſſeur, non compriſe la ſaillie <lb/>du ſoubaſſement, hors du nud duquel ſera fait retraite de trois <lb/>pouces par dehors & </s> <s xml:id="echoid-s12927" xml:space="preserve">de deux par dedans, & </s> <s xml:id="echoid-s12928" xml:space="preserve">ces murs ſeront éle-<lb/>vés de onze pieds juſqu’à la hauteur du deſſous du plinte qui aura <lb/>un pouce de ſaillie, & </s> <s xml:id="echoid-s12929" xml:space="preserve">huit de hauteur.</s> <s xml:id="echoid-s12930" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12931" xml:space="preserve">On élevera enſuite les murs du premier étage de dix pieds au <lb/>deſſus du plinte, & </s> <s xml:id="echoid-s12932" xml:space="preserve">on obſervera de leur faire faire une retraite <lb/>d’un pouce par devant ſur l’aplomb des murs inferieurs (ce qui <lb/>s’executera de même au deſſus du plinte du ſecond étage) & </s> <s xml:id="echoid-s12933" xml:space="preserve">leur <lb/>ſommet ſera terminé par un entablement decoré ſuivant le deſſein, <lb/>mis bien de niveau, & </s> <s xml:id="echoid-s12934" xml:space="preserve">conſtruit de pierres de taille, ainſi que le <lb/>plinte, ou de briques choiſies, poſées en liaiſon dans le corps du <lb/>mur.</s> <s xml:id="echoid-s12935" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12936" xml:space="preserve">Tous les murs de refend auront deux pieds d’epaiſſeur dans les <lb/>fondemens, & </s> <s xml:id="echoid-s12937" xml:space="preserve">ſeront réduits à un pied & </s> <s xml:id="echoid-s12938" xml:space="preserve">demi au deſſus, obſer-<lb/>vant de leur donner auſſi trois pouces de retraite de chaque côté, <lb/>& </s> <s xml:id="echoid-s12939" xml:space="preserve">de les élever avec un peu de fruit pour être réduits à ſeize pou-<lb/>ces d’épaiſſeur au deſſus du premier plancher, & </s> <s xml:id="echoid-s12940" xml:space="preserve">à quatorze au-<lb/>deſſus du ſecond, le tout conſtruit de même que les murs de face, <lb/>avec moëlon & </s> <s xml:id="echoid-s12941" xml:space="preserve">mortier compoſé comme ci-devant, puis crépis <lb/>proprement, & </s> <s xml:id="echoid-s12942" xml:space="preserve">blanchis des deux côtés.</s> <s xml:id="echoid-s12943" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12944" xml:space="preserve">Les murs de cloiſon, ainſi que les aîles & </s> <s xml:id="echoid-s12945" xml:space="preserve">faces des lucarnes, ſe-<lb/>ront conſtruits de brique; </s> <s xml:id="echoid-s12946" xml:space="preserve">ſçavoir, les faces ſur dix-huit pouces <lb/>d’épaiſſeur, & </s> <s xml:id="echoid-s12947" xml:space="preserve">les aîles & </s> <s xml:id="echoid-s12948" xml:space="preserve">cloiſons ſur ſix pouces ſeulement. </s> <s xml:id="echoid-s12949" xml:space="preserve">Les <lb/>contre-cœurs des grandes cheminées ſeront auſſi faits de brique ſur <lb/>neuf pieds de hauteur, & </s> <s xml:id="echoid-s12950" xml:space="preserve">ceux des communes ſur quatre ſeule-<lb/>ment avec un pouce de fruit par pied. </s> <s xml:id="echoid-s12951" xml:space="preserve">Les hottes des manteaux, <lb/>languettes & </s> <s xml:id="echoid-s12952" xml:space="preserve">fermetures des cheminées, ſeront également conſtrui-<lb/>tes d’une épaiſſeur de brique, & </s> <s xml:id="echoid-s12953" xml:space="preserve">les ouvertures des tuyaux auront <pb o="43" file="0593" n="645" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> trois pieds & </s> <s xml:id="echoid-s12954" xml:space="preserve">demi de long ſur dix à onze pouces de large, & </s> <s xml:id="echoid-s12955" xml:space="preserve">trois <lb/>pieds d’élevation au deſſus du faîte, le tout bien uni & </s> <s xml:id="echoid-s12956" xml:space="preserve">crépi, & </s> <s xml:id="echoid-s12957" xml:space="preserve"><lb/>enduit dedans & </s> <s xml:id="echoid-s12958" xml:space="preserve">dehors.</s> <s xml:id="echoid-s12959" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div665" type="section" level="1" n="168"> <head xml:id="echoid-head386" xml:space="preserve"><emph style="sc">Pierre de</emph> <emph style="sc">Taille</emph>.</head> <p> <s xml:id="echoid-s12960" xml:space="preserve">Les angles du Bâtiment ſeront armés de pierres de taille, choiſies <lb/>dans la meilleure carriere du pays, non geliſſes, ni filtreuſes, po-<lb/>ſées en bonne liaiſon par aſſiſes d’un pied de hauteur ſur ſeize à dix-<lb/>huit pouces de lit, ayant les joints d’équerre avec harpe de ſix pou-<lb/>ces de chaque côté, & </s> <s xml:id="echoid-s12961" xml:space="preserve">faiſant retour alternativement de vingt & </s> <s xml:id="echoid-s12962" xml:space="preserve"><lb/>un pouces de face, & </s> <s xml:id="echoid-s12963" xml:space="preserve">de deux pieds & </s> <s xml:id="echoid-s12964" xml:space="preserve">demi. </s> <s xml:id="echoid-s12965" xml:space="preserve">Les encognures des <lb/>plintes & </s> <s xml:id="echoid-s12966" xml:space="preserve">entablement ſeront de mêmes pierres, ainſi que les pieds <lb/>droits des grandes portes d’entrées & </s> <s xml:id="echoid-s12967" xml:space="preserve">leurs fermertures, qui porte-<lb/>ront parpin d’une pierre entre deux; </s> <s xml:id="echoid-s12968" xml:space="preserve">la plus courte deſquelles fera <lb/>au moins neuf pouces de liaiſon, & </s> <s xml:id="echoid-s12969" xml:space="preserve">aura un pied & </s> <s xml:id="echoid-s12970" xml:space="preserve">demi de lon-<lb/>gueur en tête, & </s> <s xml:id="echoid-s12971" xml:space="preserve">un pied en retour de l’écoinçon; </s> <s xml:id="echoid-s12972" xml:space="preserve">les pierres des <lb/>pieds droits, qui ſeront de deux pieces, auront leurs joints bien à <lb/>l’équerre, & </s> <s xml:id="echoid-s12973" xml:space="preserve">les deux pierres formeront l’épaiſſeur du mur.</s> <s xml:id="echoid-s12974" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12975" xml:space="preserve">On eſpacera les croiſées & </s> <s xml:id="echoid-s12976" xml:space="preserve">autres portes ſuivant les meſures de <lb/>leur deſſein, leur fermeture ſera bombée par dehors & </s> <s xml:id="echoid-s12977" xml:space="preserve">par dedans, <lb/>conſtruite de pierre de taille ou de brique, ainſi que les pieds droits <lb/>avec un ſeüil ou appui de pierre dure d’une ſeule piece, de ſept <lb/>pouces d’épaiſſeur & </s> <s xml:id="echoid-s12978" xml:space="preserve">dix de largeur. </s> <s xml:id="echoid-s12979" xml:space="preserve">Apres quoi ſera faite une dé-<lb/>charge au deſſus de ces portes, & </s> <s xml:id="echoid-s12980" xml:space="preserve">croiſées, pour ſoulager leurs plat-<lb/>tes bandes.</s> <s xml:id="echoid-s12981" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div666" type="section" level="1" n="169"> <head xml:id="echoid-head387" xml:space="preserve"><emph style="sc">Charpente</emph>.</head> <p> <s xml:id="echoid-s12982" xml:space="preserve">La Charpente conſiſtera dans les pieces ſuivantes, dont tous les <lb/>bois ſeront bien équarris & </s> <s xml:id="echoid-s12983" xml:space="preserve">ſans aubier, proprement taillés & </s> <s xml:id="echoid-s12984" xml:space="preserve">aſ-<lb/>ſemblés les uns aux autres avec tenons & </s> <s xml:id="echoid-s12985" xml:space="preserve">mortoiſes bien chevillées.</s> <s xml:id="echoid-s12986" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s12987" xml:space="preserve">10. </s> <s xml:id="echoid-s12988" xml:space="preserve">Les jambes des forces des combles auront chacune dix pouces <lb/>de gros ſur .</s> <s xml:id="echoid-s12989" xml:space="preserve">..</s> <s xml:id="echoid-s12990" xml:space="preserve">. de longueur; </s> <s xml:id="echoid-s12991" xml:space="preserve">les liens dix pouces de gros ſur .</s> <s xml:id="echoid-s12992" xml:space="preserve">..</s> <s xml:id="echoid-s12993" xml:space="preserve">. <lb/>de longueur; </s> <s xml:id="echoid-s12994" xml:space="preserve">les entraits dix à douze pouces ſur .</s> <s xml:id="echoid-s12995" xml:space="preserve">..</s> <s xml:id="echoid-s12996" xml:space="preserve">.; </s> <s xml:id="echoid-s12997" xml:space="preserve">les blochets <lb/>huit à dix pouces ſur .</s> <s xml:id="echoid-s12998" xml:space="preserve">..</s> <s xml:id="echoid-s12999" xml:space="preserve">.; </s> <s xml:id="echoid-s13000" xml:space="preserve">& </s> <s xml:id="echoid-s13001" xml:space="preserve">les plattes formes ſur l’entablement <lb/>quatre, & </s> <s xml:id="echoid-s13002" xml:space="preserve">douze pouces de gros: </s> <s xml:id="echoid-s13003" xml:space="preserve">le tout de bois de chêne. </s> <s xml:id="echoid-s13004" xml:space="preserve">Le ſur-<lb/>plus de l’aſſemblage ſera de bois de ſapin.</s> <s xml:id="echoid-s13005" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13006" xml:space="preserve">20. </s> <s xml:id="echoid-s13007" xml:space="preserve">Les arbalêtriers auront .</s> <s xml:id="echoid-s13008" xml:space="preserve">..</s> <s xml:id="echoid-s13009" xml:space="preserve">. de longueur ſur huit à neuf de <lb/>gros; </s> <s xml:id="echoid-s13010" xml:space="preserve">les poinçons .</s> <s xml:id="echoid-s13011" xml:space="preserve">..</s> <s xml:id="echoid-s13012" xml:space="preserve">. de longueur ſur neuf à dix; </s> <s xml:id="echoid-s13013" xml:space="preserve">les pannes por-<lb/>teront ſur les jambes de force, & </s> <s xml:id="echoid-s13014" xml:space="preserve">auront les longueurs néceſſaires <lb/>ſur ſept à huit de gros; </s> <s xml:id="echoid-s13015" xml:space="preserve">les contrefiches .</s> <s xml:id="echoid-s13016" xml:space="preserve">..</s> <s xml:id="echoid-s13017" xml:space="preserve">. de longueur ſur ſept à <pb o="44" file="0594" n="646" rhead="LA SCIENCE DES INGENIEURS,"/> ſept de gros; </s> <s xml:id="echoid-s13018" xml:space="preserve">les chevrons .</s> <s xml:id="echoid-s13019" xml:space="preserve">..</s> <s xml:id="echoid-s13020" xml:space="preserve">. de long & </s> <s xml:id="echoid-s13021" xml:space="preserve">quatre pouces de gros, <lb/>leſquels chevrons ſeront d’une ſeule piece, & </s> <s xml:id="echoid-s13022" xml:space="preserve">eſpacés à un pied de <lb/>diſtance les uns des autres, bien brandis & </s> <s xml:id="echoid-s13023" xml:space="preserve">arrêtés ſur les pannes, & </s> <s xml:id="echoid-s13024" xml:space="preserve"><lb/>les empanons bien dreſſés à la ligne.</s> <s xml:id="echoid-s13025" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13026" xml:space="preserve">Tous les ſoliveaux des planchers ſeront poſés bien de niveau à <lb/>deux pieds de diſtance l’un de l’autre de milieu en milieu, & </s> <s xml:id="echoid-s13027" xml:space="preserve">au-<lb/>ront .</s> <s xml:id="echoid-s13028" xml:space="preserve">..</s> <s xml:id="echoid-s13029" xml:space="preserve">. de longueur ſur huit à neuf pouces de groſſeur; </s> <s xml:id="echoid-s13030" xml:space="preserve">on y ob-<lb/>ſervera les enchevetrures néceſſaires. </s> <s xml:id="echoid-s13031" xml:space="preserve">Les giſtes ou lambourdes <lb/>ſous le plancher du rez-de-chauſſée auront quatre à cinq pouces de <lb/>gros ſur les longueurs néceſſaires, & </s> <s xml:id="echoid-s13032" xml:space="preserve">ſeront eſpacées de deux pieds <lb/>& </s> <s xml:id="echoid-s13033" xml:space="preserve">demi de milieu en milieu. </s> <s xml:id="echoid-s13034" xml:space="preserve">La ſabliere, qui doit être poſée ſur les <lb/>murs, aura douze pouces de largeur ſur trois à quatre d’épaiſſeur. <lb/></s> <s xml:id="echoid-s13035" xml:space="preserve">Les poteaux des cloiſons auront cinq à ſix pouces de groſſeur, & </s> <s xml:id="echoid-s13036" xml:space="preserve"><lb/>ſeront aſſemblés haut & </s> <s xml:id="echoid-s13037" xml:space="preserve">bas à tenons & </s> <s xml:id="echoid-s13038" xml:space="preserve">mortoiſes dans des ſablieres <lb/>de ſix à ſept pouces de groſſeur, & </s> <s xml:id="echoid-s13039" xml:space="preserve">delardés pour retenir la maçon-<lb/>nerie des panneaux.</s> <s xml:id="echoid-s13040" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13041" xml:space="preserve">Tous les bois des eſcaliers ſeront de la même qualité & </s> <s xml:id="echoid-s13042" xml:space="preserve">dreſſés <lb/>au rabot à vive arête avec les moulures convenables. </s> <s xml:id="echoid-s13043" xml:space="preserve">Les baluſtres <lb/>ſeront auſſi de même bois, & </s> <s xml:id="echoid-s13044" xml:space="preserve">tournés ou faits à la main. </s> <s xml:id="echoid-s13045" xml:space="preserve">Les mar-<lb/>ches maſſives, délardées avec un demi rond ſur le devant; </s> <s xml:id="echoid-s13046" xml:space="preserve">les li-<lb/>mons ſeront gros de cinq à dix; </s> <s xml:id="echoid-s13047" xml:space="preserve">les noyaux de cinq; </s> <s xml:id="echoid-s13048" xml:space="preserve">les appuis & </s> <s xml:id="echoid-s13049" xml:space="preserve"><lb/>les potelets de trois à cinq.</s> <s xml:id="echoid-s13050" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div667" type="section" level="1" n="170"> <head xml:id="echoid-head388" xml:space="preserve"><emph style="sc">Couverture</emph>.</head> <p> <s xml:id="echoid-s13051" xml:space="preserve">On n’employera aux couvertures que des tuiles choiſies & </s> <s xml:id="echoid-s13052" xml:space="preserve">bien <lb/>cuite. </s> <s xml:id="echoid-s13053" xml:space="preserve">Les lattes ſeront de bon bois de ſapin de droit fil ſans aubier, <lb/>bien clouées ſur chaques chevrons d’un clou à latte, & </s> <s xml:id="echoid-s13054" xml:space="preserve">poſées à <lb/>diſtance égale & </s> <s xml:id="echoid-s13055" xml:space="preserve">de niveau, afin que les pureaux le ſoient auſſi.</s> <s xml:id="echoid-s13056" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div668" type="section" level="1" n="171"> <head xml:id="echoid-head389" xml:space="preserve"><emph style="sc">Menuiserie</emph>.</head> <p> <s xml:id="echoid-s13057" xml:space="preserve">Les planchers au deſſus des ſolives ſeront faits de planches de ſa-<lb/>pin bien ſec d’un pouce ou un pouce & </s> <s xml:id="echoid-s13058" xml:space="preserve">demi d’épaiſſeur, blanchies <lb/>du côté vû, aſſemblées à raînure & </s> <s xml:id="echoid-s13059" xml:space="preserve">languette, bien dreſſées & </s> <s xml:id="echoid-s13060" xml:space="preserve">at-<lb/>tachées aux ſolives avec autant de clous qu’il ſera néceſſaire pour <lb/>les empêcher de ſe déjetter.</s> <s xml:id="echoid-s13061" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13062" xml:space="preserve">Toutes les croiſées de menuiſerie auront ſept pieds & </s> <s xml:id="echoid-s13063" xml:space="preserve">demi de hau-<lb/>teur ſur quatre pieds quatre pouces de largeur, & </s> <s xml:id="echoid-s13064" xml:space="preserve">ſeront aſſemblées <lb/>à bouëment. </s> <s xml:id="echoid-s13065" xml:space="preserve">Les chaſſis dormans auront deux pouces d’épaiſſeur, <lb/>& </s> <s xml:id="echoid-s13066" xml:space="preserve">ſeront ornés de meneaux ronds ſur les montans & </s> <s xml:id="echoid-s13067" xml:space="preserve">traverſes, avec <pb o="45" file="0595" n="647" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> un quart de rond ſur l’apui élegi dans ces traverſes. </s> <s xml:id="echoid-s13068" xml:space="preserve">Les chaſſis à <lb/>verre auront un pouce & </s> <s xml:id="echoid-s13069" xml:space="preserve">demi d’épaiſſeur, & </s> <s xml:id="echoid-s13070" xml:space="preserve">les volets un pouce, <lb/>le tout de bon bois de chêne bien ſec & </s> <s xml:id="echoid-s13071" xml:space="preserve">bien aſſemblé, garni de ſes <lb/>ferrures qui conſiſteront pour chaque croiſée en huit gonds, huit <lb/>fiches ou gonds à charniere, quatre targettes, quatre crampons, & </s> <s xml:id="echoid-s13072" xml:space="preserve"><lb/>huit équerres proprement limés & </s> <s xml:id="echoid-s13073" xml:space="preserve">mis en œuvre. </s> <s xml:id="echoid-s13074" xml:space="preserve">Chaque panneau <lb/>des croiſées ſera garni de verre blanc poſé en plomb ou en maſtic, <lb/>ſoutenu & </s> <s xml:id="echoid-s13075" xml:space="preserve">arrêté par trois vergettes de fer arrondies, bien clouées <lb/>aux panneaux, & </s> <s xml:id="echoid-s13076" xml:space="preserve">attachées avec bonnes attaches de plomb ſuivant <lb/>l’uſage.</s> <s xml:id="echoid-s13077" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13078" xml:space="preserve">S’il eſt jugé néceſſaire de barrer ces croiſées, on y employera des <lb/>barreaux de fer quarré de trois quarts de pouce de groſſeur, qui <lb/>entreront de quatre pouces dans les appuis & </s> <s xml:id="echoid-s13079" xml:space="preserve">couvertes, & </s> <s xml:id="echoid-s13080" xml:space="preserve">ſeront <lb/>ſcellés en plomb. </s> <s xml:id="echoid-s13081" xml:space="preserve">Les portes communes ſeront auſſi de bon bois de <lb/>chêne bien ſec, de ſix pieds & </s> <s xml:id="echoid-s13082" xml:space="preserve">demi de hauteur, de trois de largeur, <lb/>& </s> <s xml:id="echoid-s13083" xml:space="preserve">un pouce & </s> <s xml:id="echoid-s13084" xml:space="preserve">demi d’épaiſſeur, bien aſſemblées avec clef, collées <lb/>& </s> <s xml:id="echoid-s13085" xml:space="preserve">emboëttées par les deux bouts avec des emboëtures de cinq à ſix <lb/>pouces de haut, & </s> <s xml:id="echoid-s13086" xml:space="preserve">garnies chacune d’une ſerrure à tour & </s> <s xml:id="echoid-s13087" xml:space="preserve">demi, <lb/>benardée à l’uſage de France, bien limée & </s> <s xml:id="echoid-s13088" xml:space="preserve">polie de même que ſes <lb/>pentures & </s> <s xml:id="echoid-s13089" xml:space="preserve">gonds qui ſeront ſeulement limés, brunis, & </s> <s xml:id="echoid-s13090" xml:space="preserve">d’une for-<lb/>ce convenable.</s> <s xml:id="echoid-s13091" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13092" xml:space="preserve">Les portes à deux ventaux auront chacune quatre pieds & </s> <s xml:id="echoid-s13093" xml:space="preserve">demi <lb/>de large, & </s> <s xml:id="echoid-s13094" xml:space="preserve">ſept à huit de hauteur, & </s> <s xml:id="echoid-s13095" xml:space="preserve">ſeront de bois de chêne d’un <lb/>pouce & </s> <s xml:id="echoid-s13096" xml:space="preserve">demi à deux pouces d’épaiſſeur d’aſſemblage, & </s> <s xml:id="echoid-s13097" xml:space="preserve">d’un pouce <lb/>ſeulement pour les panneaux. </s> <s xml:id="echoid-s13098" xml:space="preserve">Elles ſeront collées & </s> <s xml:id="echoid-s13099" xml:space="preserve">emboëtées com-<lb/>me les précedentes, ſur la largeur & </s> <s xml:id="echoid-s13100" xml:space="preserve">épaiſſeur du bois, & </s> <s xml:id="echoid-s13101" xml:space="preserve">bien ra-<lb/>bottées de deux côtés. </s> <s xml:id="echoid-s13102" xml:space="preserve">Seront de plus garnies de reſſorts, verroüils, <lb/>ſerrures & </s> <s xml:id="echoid-s13103" xml:space="preserve">autres ferrures néceſſaires, le tout proprement limé & </s> <s xml:id="echoid-s13104" xml:space="preserve"><lb/>de force ſuffiſante.</s> <s xml:id="echoid-s13105" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13106" xml:space="preserve">Les grandes portes cocheres auront neuf pieds de largeur ſur dou-<lb/>ze à treize de hauteur, leurs battans ſeront épais de quatre pouces <lb/>& </s> <s xml:id="echoid-s13107" xml:space="preserve">larges de huit à neuf, les batis de trois pouces d’épaiſſeur, les <lb/>cadres de quatre, & </s> <s xml:id="echoid-s13108" xml:space="preserve">les panneaux d’un pouce & </s> <s xml:id="echoid-s13109" xml:space="preserve">demi.</s> <s xml:id="echoid-s13110" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13111" xml:space="preserve">Le lambris des plafonds & </s> <s xml:id="echoid-s13112" xml:space="preserve">côtés des chambres ſera fait de bon <lb/>bois de chêne ou de ſapin bien ſec, à grands panneaux aſſemblés, <lb/>collés & </s> <s xml:id="echoid-s13113" xml:space="preserve">bien arrêtés dans les murs, ou de planches ſeulement bien <lb/>blanchies du côté vû, & </s> <s xml:id="echoid-s13114" xml:space="preserve">recouvertes de liteau ſur tous les joints.</s> <s xml:id="echoid-s13115" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13116" xml:space="preserve">Les conditions de cet Abregé peuvent s’appliquer aux Cazernes, <lb/>Pavillons, Arſenaux, Logemens d’Etat-Major, & </s> <s xml:id="echoid-s13117" xml:space="preserve">autres, en chan-<lb/>geant ſeulement ce qui pourra faire quelque difference tant dans la <lb/>décoration, que dans la pierre de taille & </s> <s xml:id="echoid-s13118" xml:space="preserve">la qualité des materiaux <pb o="46" file="0596" n="648" rhead="LASCIENCE DES INGENIEURS,"/> qui ſont tous arbitraires ſuivant les lieux, la deſtination, & </s> <s xml:id="echoid-s13119" xml:space="preserve">la dé <lb/>penſe qu’on juge à propos d’y faire.</s> <s xml:id="echoid-s13120" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div669" type="section" level="1" n="172"> <head xml:id="echoid-head390" xml:space="preserve">DE LA FORME DES ADJUDICATIONS, <lb/>Formalités qui s’y obſervent, & du Stile dans lequel <lb/>elles ſont conçûës.</head> <p> <s xml:id="echoid-s13121" xml:space="preserve">LE Devis étant reglé, & </s> <s xml:id="echoid-s13122" xml:space="preserve">partie des fonds aſſignée, l’Intendant <lb/>de la Province fait publier & </s> <s xml:id="echoid-s13123" xml:space="preserve">afficher dans toutes les Places <lb/>de ſon Département, & </s> <s xml:id="echoid-s13124" xml:space="preserve">même dans les Provinces voiſines, qu’à tel <lb/>jour nommé, il ſera procedé en ſon Hôtel & </s> <s xml:id="echoid-s13125" xml:space="preserve">par devant lui, à l’ad-<lb/>judication des ouvrages à faire pour la conſtruction de la nouvelle <lb/>Place, où ſeront admis tous ceux qui voudront ſe charger de cette <lb/>entrepriſe, & </s> <s xml:id="echoid-s13126" xml:space="preserve">faire la condition du Roi la meilleure, en donnant <lb/>bonne & </s> <s xml:id="echoid-s13127" xml:space="preserve">ſuffiſante caution.</s> <s xml:id="echoid-s13128" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13129" xml:space="preserve">Le jour arrivé, l’Intendant, accompagné du Directeur des Forti-<lb/>fications, & </s> <s xml:id="echoid-s13130" xml:space="preserve">autres aſſemblés à ce ſujet, fait lire à haute voix le De-<lb/>vis tout entier, afin que les prétendans à ladite entrepriſe puiſſent <lb/>être informés de la nature des ouvrages qu’on veut conſtruire, & </s> <s xml:id="echoid-s13131" xml:space="preserve"><lb/>des conditions auſquelles ils doivent s’aſſujettir; </s> <s xml:id="echoid-s13132" xml:space="preserve">apres quoi com-<lb/>mencent les differentes miſes des Entrepreneurs, eſpece d’ouvrage <lb/>par eſpece d’ouvrage, qu’on inſcrit à meſure qu’elles ſe font. </s> <s xml:id="echoid-s13133" xml:space="preserve">Puis <lb/>quand il ne ſe trouve plus perſonne qui mette au rabais, on allume <lb/>trois feux de bougie conſecutifs, pendant la durée deſquels un nou-<lb/>vel Entrepreneur peut encore être reçu à faire un nouveau rabais; <lb/></s> <s xml:id="echoid-s13134" xml:space="preserve">& </s> <s xml:id="echoid-s13135" xml:space="preserve">enfin aprés l’extinction deſdits feux, l’entrepriſe eſt adjugée à <lb/>celui qui a fait la condition du Roy la meilleure, & </s> <s xml:id="echoid-s13136" xml:space="preserve">on en dreſſe <lb/>procès verbal à peu près dans les termes ſuivans.</s> <s xml:id="echoid-s13137" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13138" xml:space="preserve">Ce jourd’hui .</s> <s xml:id="echoid-s13139" xml:space="preserve">.. </s> <s xml:id="echoid-s13140" xml:space="preserve">mois, an, & </s> <s xml:id="echoid-s13141" xml:space="preserve">jour .</s> <s xml:id="echoid-s13142" xml:space="preserve">.. </s> <s xml:id="echoid-s13143" xml:space="preserve">Nous .</s> <s xml:id="echoid-s13144" xml:space="preserve">..</s> <s xml:id="echoid-s13145" xml:space="preserve">. noms & </s> <s xml:id="echoid-s13146" xml:space="preserve">qualités <lb/>de l’Intendant de la Province, étant en notre Hôtel à .</s> <s xml:id="echoid-s13147" xml:space="preserve">.. </s> <s xml:id="echoid-s13148" xml:space="preserve">nom de <lb/>la Ville, après pluſieurs affiches & </s> <s xml:id="echoid-s13149" xml:space="preserve">publications faites tant dans la-<lb/>dite Ville, que dans les autress Places de la Province, portant que <lb/>ledit jour il ſeroit par nous procedé à l’adjucation & </s> <s xml:id="echoid-s13150" xml:space="preserve">au rabais des <lb/>ouvrages que le Roy a ordonné être faits pour la conſtruction d’une <lb/>Place neuve à.</s> <s xml:id="echoid-s13151" xml:space="preserve">..</s> <s xml:id="echoid-s13152" xml:space="preserve">. nom du lieu qu’on doit fortifier, ſuivant le deſ-<lb/>ſein de M.</s> <s xml:id="echoid-s13153" xml:space="preserve">..</s> <s xml:id="echoid-s13154" xml:space="preserve">.. </s> <s xml:id="echoid-s13155" xml:space="preserve">y avons procedé en preſence & </s> <s xml:id="echoid-s13156" xml:space="preserve">de l’avis de M. </s> <s xml:id="echoid-s13157" xml:space="preserve">.</s> <s xml:id="echoid-s13158" xml:space="preserve">..</s> <s xml:id="echoid-s13159" xml:space="preserve">. <lb/>Ingenieur-Directeur des Fortifications deſdites Places, aux clauſes <lb/>& </s> <s xml:id="echoid-s13160" xml:space="preserve">conditions dont la teneur s’enſuit.</s> <s xml:id="echoid-s13161" xml:space="preserve"/> </p> <pb o="47" file="0597" n="649" rhead="LVI. VI. DE LA MANIERE DE FAIRE LES DEVIS"/> <p style="it"> <s xml:id="echoid-s13162" xml:space="preserve">Devis des ouvrages, &</s> <s xml:id="echoid-s13163" xml:space="preserve">c. </s> <s xml:id="echoid-s13164" xml:space="preserve">On copie ici le Devis tout entier dans la <lb/>forme qui a été preſcrite, & </s> <s xml:id="echoid-s13165" xml:space="preserve">après quoi on continuë le procès verbal de <lb/>la maniere ſuivante.</s> <s xml:id="echoid-s13166" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13167" xml:space="preserve">Les Entrepreneurs, acceptant les conditions du preſent Devis, <lb/>ſe fourniront de tous les materiaux, peines d’ouvriers, voitures, <lb/>échaffaudages, ponts, planches, outils, engins, cordages, & </s> <s xml:id="echoid-s13168" xml:space="preserve">gene-<lb/>ralement de toutes les choſes néceſſaires à l’execution de leur en-<lb/>trepriſe, ſeront auſſi à leurs frais tous les épuiſemens d’eaux; </s> <s xml:id="echoid-s13169" xml:space="preserve">& </s> <s xml:id="echoid-s13170" xml:space="preserve">ſe-<lb/>ront obligés, un an après la conſtruction de la Place, de refaire tous <lb/>les joints de la maçonnerie avec bon mortier de chaux & </s> <s xml:id="echoid-s13171" xml:space="preserve">ſable, ſans <lb/>qu’ils puiſſent prétendre autre choſe de la part de Sa Majeſté, que <lb/>les prix portés par l’adjudication qui leur en ſera faite, obſervans <lb/>qu’aucune terre ne ſoit toiſée deux fois, quoique parties ſoient ſu-<lb/>jettes à un ſecond tranſport, à l’éxception toutefois de celles qui <lb/>ſeront paſſées à la claye, & </s> <s xml:id="echoid-s13172" xml:space="preserve">des terres douces qui ſeront miſes à part <lb/>pour former les parapets, dont on tiendra compte pour le ſecond <lb/>tranſport; </s> <s xml:id="echoid-s13173" xml:space="preserve">on obſervera encore qu’aucun remblais ne ſoit toiſé, ni <lb/>aucun vuide dans le cube de la maçonnerie. </s> <s xml:id="echoid-s13174" xml:space="preserve">Seront au ſurplus leſ-<lb/>dits ouvrages executés avec toute la diligence poſſible, ſujets aux <lb/>verifications & </s> <s xml:id="echoid-s13175" xml:space="preserve">receptions ſuivant la maniere accoutumée, & </s> <s xml:id="echoid-s13176" xml:space="preserve">ga-<lb/>rantis un an après qu’ils auront été reçûs par les Ingenieurs qui en <lb/>ſeront chargés.</s> <s xml:id="echoid-s13177" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13178" xml:space="preserve">Au moyen deſdits prix, les Entrepreneurs ſeront exemts de guet <lb/>& </s> <s xml:id="echoid-s13179" xml:space="preserve">garde, de toute corvée & </s> <s xml:id="echoid-s13180" xml:space="preserve">logement des gens de guerre, & </s> <s xml:id="echoid-s13181" xml:space="preserve">il <lb/>leur ſera permis de faire couper tous les gazons dont ils auront be-<lb/>ſoin, dans les prairies ou vieilles pâtures les plus à portée, qui leur <lb/>ſeront marquées par notre Subdelegué, ou par les Magiſtrats des <lb/>lieux, & </s> <s xml:id="echoid-s13182" xml:space="preserve">l’Ingenieur en chef de la Place, ſans que leſdits Entrepre-<lb/>neurs ſoient obligés d’en rien payer aux Proprietaires des terres. </s> <s xml:id="echoid-s13183" xml:space="preserve">Si la <lb/>Place eſt bien frontiere, & </s> <s xml:id="echoid-s13184" xml:space="preserve">qu’on ſoit en tems de guerre, on pourra ajoûter <lb/>qu’il ſera donné à l’Entrepreneur les eſcortes néceſſaires pour la conſer-<lb/>vation de ſes beſtiaux, ſoit chevaux ou bœufs employés à voiturer les <lb/>materiaux pour la conſtruction des ouvrages. </s> <s xml:id="echoid-s13185" xml:space="preserve">Que ſi leſdits chevaux ou <lb/>bœufs viennent à être pris avec les eſcortes par quelque parti ennemi, <lb/>ſoit de troupes regléés ou autres, en voiturant les materiaux, l’Entre-<lb/>preneur en ſera indemniſé ſuivant leur juſte valeur. </s> <s xml:id="echoid-s13186" xml:space="preserve">Qu’au cas que ledit <lb/>Entrepreneur, ou ſes Commis, ſoient pris priſonniers par les ennemis en <lb/>faiſant le Service du Roy, leur rançon ſera payée par Sa Majeſté.</s> <s xml:id="echoid-s13187" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13188" xml:space="preserve">Et après lecture faite du Devis ci-deſſus à haute & </s> <s xml:id="echoid-s13189" xml:space="preserve">intelligible <lb/> <anchor type="note" xlink:label="note-0597-01a" xlink:href="note-0597-01"/> voix, que les Entrepreneurs aſſemblés pour mettre leur rabais ont <lb/>dit entendre, leſdits ouvrages ont été mis à prix, ſçavoir,</s> </p> <div xml:id="echoid-div669" type="float" level="2" n="1"> <note position="right" xlink:label="note-0597-01" xlink:href="note-0597-01a" xml:space="preserve">Suite dis <lb/>trocès ver-<lb/>bal.</note> </div> <pb o="48" file="0598" n="650" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s13190" xml:space="preserve">La toiſe cube de groſſe maçonnerie, par le Sieur.</s> <s xml:id="echoid-s13191" xml:space="preserve">.. </s> <s xml:id="echoid-s13192" xml:space="preserve">à trente liv. <lb/></s> <s xml:id="echoid-s13193" xml:space="preserve">par le Sieur.</s> <s xml:id="echoid-s13194" xml:space="preserve">.. </s> <s xml:id="echoid-s13195" xml:space="preserve">à vingt-cinq livres, par le Sieur.</s> <s xml:id="echoid-s13196" xml:space="preserve">.. </s> <s xml:id="echoid-s13197" xml:space="preserve">à vingt-deux <lb/>livres, & </s> <s xml:id="echoid-s13198" xml:space="preserve">par le ſieur.</s> <s xml:id="echoid-s13199" xml:space="preserve">.. </s> <s xml:id="echoid-s13200" xml:space="preserve">à vingt livres.</s> <s xml:id="echoid-s13201" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13202" xml:space="preserve">La toiſe cube des terres, &</s> <s xml:id="echoid-s13203" xml:space="preserve">c.</s> <s xml:id="echoid-s13204" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s13205" xml:space="preserve">Et ainſi de ſuite, déſignant chaque eſpece differente d’ouvrages, ſans <lb/>en oublier aucun, s’il eſt poſſible, pour éviter toute conteſtation dans la <lb/>ſuite, & </s> <s xml:id="echoid-s13206" xml:space="preserve">ſpecifiant à chaque article toutes les miſes qui y ont été faites <lb/>ſuivant l’ordre, & </s> <s xml:id="echoid-s13207" xml:space="preserve">finiſſant par la derniere & </s> <s xml:id="echoid-s13208" xml:space="preserve">la plus foible.</s> <s xml:id="echoid-s13209" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13210" xml:space="preserve">Après quoi, nous avons fait allumer trois feux conſecutifs, pour <lb/> <anchor type="note" xlink:label="note-0598-01a" xlink:href="note-0598-01"/> voir ſi pendant leur durée quelque Particulier de ladite Aſſem-<lb/>blée ne feroit point quelque nouveau rabais; </s> <s xml:id="echoid-s13211" xml:space="preserve">mais leſdits feux <lb/>s’étant tous éteints, & </s> <s xml:id="echoid-s13212" xml:space="preserve">ayant fait trois autres remiſes à differens <lb/>jours ſans qu’il ſe ſoit preſenté perſonne qui ait voulu mettre <lb/>leſdits ouvrages à plus bas prix, ni faire la condition du Roy plus <lb/>avantageuſe que le Sieur.</s> <s xml:id="echoid-s13213" xml:space="preserve">.. </s> <s xml:id="echoid-s13214" xml:space="preserve">Nous, de l’avis de M.</s> <s xml:id="echoid-s13215" xml:space="preserve">..</s> <s xml:id="echoid-s13216" xml:space="preserve">. Directeur, <lb/>& </s> <s xml:id="echoid-s13217" xml:space="preserve">ſous le bon plaiſir de Sa Majeſté, lui avons adjugé & </s> <s xml:id="echoid-s13218" xml:space="preserve">adjugeons <lb/>leſdits ouvrages, à charge de donner bonne & </s> <s xml:id="echoid-s13219" xml:space="preserve">ſuffiſante caution. <lb/></s> <s xml:id="echoid-s13220" xml:space="preserve">Sçavoir,</s> </p> <div xml:id="echoid-div670" type="float" level="2" n="2"> <note position="left" xlink:label="note-0598-01" xlink:href="note-0598-01a" xml:space="preserve">Suite du-<lb/>procès ver-<lb/>bal.</note> </div> <p> <s xml:id="echoid-s13221" xml:space="preserve">Audit Sieur.</s> <s xml:id="echoid-s13222" xml:space="preserve">..</s> <s xml:id="echoid-s13223" xml:space="preserve">. la toiſe cube de maçonnerie à vingt livres.</s> <s xml:id="echoid-s13224" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13225" xml:space="preserve">La toiſe cube des terres, &</s> <s xml:id="echoid-s13226" xml:space="preserve">c.</s> <s xml:id="echoid-s13227" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s13228" xml:space="preserve">Reprenant ainſi de ſuite toutes les dernieres miſes dudit Entrepre-<lb/>neur.</s> <s xml:id="echoid-s13229" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13230" xml:space="preserve">Leſquels prix ſeront payés audit Entrepreneur des derniers de Sa <lb/> <anchor type="note" xlink:label="note-0598-02a" xlink:href="note-0598-02"/> Majeſté ſur les fonds faits & </s> <s xml:id="echoid-s13231" xml:space="preserve">à faire pour leſdits ouvrages au fur & </s> <s xml:id="echoid-s13232" xml:space="preserve"><lb/>à meſure de leur avancement, & </s> <s xml:id="echoid-s13233" xml:space="preserve">ſur les billets de l’Ingenieur qui <lb/>aura la principale conduite. </s> <s xml:id="echoid-s13234" xml:space="preserve">Fait à.</s> <s xml:id="echoid-s13235" xml:space="preserve">.. </s> <s xml:id="echoid-s13236" xml:space="preserve">jour & </s> <s xml:id="echoid-s13237" xml:space="preserve">an que deſſus, ſigné <lb/>l’Intendant, le Directeur, & </s> <s xml:id="echoid-s13238" xml:space="preserve">l’Entrepreneur.</s> <s xml:id="echoid-s13239" xml:space="preserve"/> </p> <div xml:id="echoid-div671" type="float" level="2" n="3"> <note position="left" xlink:label="note-0598-02" xlink:href="note-0598-02a" xml:space="preserve">Suite du-<lb/>procès ver-<lb/>bal.</note> </div> <p> <s xml:id="echoid-s13240" xml:space="preserve">Et à l’inſtant ledit Sieur.</s> <s xml:id="echoid-s13241" xml:space="preserve">.. </s> <s xml:id="echoid-s13242" xml:space="preserve">nous a preſenté pour Caution la per-<lb/>ſonne de Guillaume.</s> <s xml:id="echoid-s13243" xml:space="preserve">.. </s> <s xml:id="echoid-s13244" xml:space="preserve">demeurant à.</s> <s xml:id="echoid-s13245" xml:space="preserve">.. </s> <s xml:id="echoid-s13246" xml:space="preserve">lequel tant en cette qua-<lb/>lité, qu’en celle d’Aſſocié, s’eſt obligé pour ce preſent, & </s> <s xml:id="echoid-s13247" xml:space="preserve">s’oblige <lb/>ſolidairement comme pour les propres deniers & </s> <s xml:id="echoid-s13248" xml:space="preserve">affaires de Sa Ma-<lb/>jeſté, & </s> <s xml:id="echoid-s13249" xml:space="preserve">par les mêmes voyes que ledit Entrepreneur eſt tenu. </s> <s xml:id="echoid-s13250" xml:space="preserve">Fait <lb/>leſdits jour & </s> <s xml:id="echoid-s13251" xml:space="preserve">an que deſſus. </s> <s xml:id="echoid-s13252" xml:space="preserve">Signé l’Intendant de la Province & </s> <s xml:id="echoid-s13253" xml:space="preserve">la <lb/>Caution.</s> <s xml:id="echoid-s13254" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13255" xml:space="preserve">Pour la conduite que les Ingenieurs doivent avoir avec les En-<lb/>trepreneurs, il faut d’abord ſe perſuader, que comme les entrepri-<lb/>ſes ne ſe font qu’en vûe du gain, on a beſoin de toute ſon atten-<lb/>tion pour empêcher que ce motif n’occaſionne bien des mal-façons, <lb/>ou de la négligence dans le travail. </s> <s xml:id="echoid-s13256" xml:space="preserve">Ainſi, pour y obvier, il eſt du <lb/>devoir de l’Ingenieur de n’épargner, ni ſes ſoins, ni ſes peines, pour <lb/>que toutes choſes ſoient faites dans l’ordre, & </s> <s xml:id="echoid-s13257" xml:space="preserve">d’être toûjours pre- <pb o="49" file="0599" n="651" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> ſent, autant qu’il eſt poſſible à tout ce qui s’execute. </s> <s xml:id="echoid-s13258" xml:space="preserve">Les maçon-<lb/>neries ſur-tout demandent une preſence actuelle, de même que la <lb/>façon des mortiers, & </s> <s xml:id="echoid-s13259" xml:space="preserve">le choix de l’emploi des pierres: </s> <s xml:id="echoid-s13260" xml:space="preserve">il ne faut <lb/>avoir ſur cela aucune indulgence, les ouvriers ſe relâchent aſſez <lb/>d’ailleurs. </s> <s xml:id="echoid-s13261" xml:space="preserve">On doit auſſi avoir beaucoup de regularité dans ſes regiſ-<lb/>tres, dans la preſſe des attachemens, dans la diſtribution des té-<lb/>moins, dans l’acceptation des materiaux, & </s> <s xml:id="echoid-s13262" xml:space="preserve">ne pas oublier de fixer <lb/>la groſſeur des bois avant que l’ouvrage ſe faſſe, de crainte que <lb/>l’Entrepreneur ne meſuſe de la condeſcendance qu’on auroit de lui <lb/>laiſſer employer à ſa volonté, & </s> <s xml:id="echoid-s13263" xml:space="preserve">qu’il ne multiplie mal à propos le <lb/>nombre de cent de ſolives; </s> <s xml:id="echoid-s13264" xml:space="preserve">abus qui n’eſt pas moins grand, & </s> <s xml:id="echoid-s13265" xml:space="preserve">qui <lb/>ſouvent n’eſt pas moins préjudiciable à l’ouvrage, que celui d’em-<lb/>ployer des bois trop foibles; </s> <s xml:id="echoid-s13266" xml:space="preserve">il en eſt de même des ferrures & </s> <s xml:id="echoid-s13267" xml:space="preserve">de <lb/>pluſieurs autres choſes, qu’il ſeroit trop long de détailler.</s> <s xml:id="echoid-s13268" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13269" xml:space="preserve">D’un autre côté, il ne faut pas non plus être inquiet, ni vetiller <lb/>ſans ſujet: </s> <s xml:id="echoid-s13270" xml:space="preserve">le bien du ſervice veut que l’Entrepreneur s’execute, & </s> <s xml:id="echoid-s13271" xml:space="preserve"><lb/>qu’il n’épargne rien pour la bonté des ouvrages; </s> <s xml:id="echoid-s13272" xml:space="preserve">mais, il veut auſſi <lb/>que le même Entrepreneur trouve, en travaillant bien, dequoi ſe dé-<lb/>dommager de ſes frais & </s> <s xml:id="echoid-s13273" xml:space="preserve">de ſes peines. </s> <s xml:id="echoid-s13274" xml:space="preserve">Si cependant il a fait un mau-<lb/>vais marché, ou qu’il lui arrive dans le cours du travail des con-<lb/>tre-tems fàcheux & </s> <s xml:id="echoid-s13275" xml:space="preserve">inévitables, ce n’eſt point à l’Ingenieur à y en-<lb/>trer: </s> <s xml:id="echoid-s13276" xml:space="preserve">l’Entrepreneur a la voye de repreſentation à la Cour, comme <lb/>cela eſt arrivé pluſieurs fois; </s> <s xml:id="echoid-s13277" xml:space="preserve">&</s> <s xml:id="echoid-s13278" xml:space="preserve">, quand il eſt bien fondé, il eſt com-<lb/>me aſſûré de trouver dans la bonté du Roy de quoi l’indemniſer <lb/>de ſes pertes. </s> <s xml:id="echoid-s13279" xml:space="preserve">Mais, qu’on s’embaraſſe peu d’ailleurs des tons plain-<lb/>tifs qui ſont aſſez ordinaires à ces Meſſieurs. </s> <s xml:id="echoid-s13280" xml:space="preserve">Un Ingenieur, qui ſçait <lb/>ſon métier, voit aiſément ce qui eſt juſte & </s> <s xml:id="echoid-s13281" xml:space="preserve">raiſonnable à faire; </s> <s xml:id="echoid-s13282" xml:space="preserve">& </s> <s xml:id="echoid-s13283" xml:space="preserve"><lb/>pour peu qu’il prenne la peine d’entrer dans le détail de chaque <lb/>choſe, il connoît d’un coup d’œil à quoi il doit s’en tenir.</s> <s xml:id="echoid-s13284" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13285" xml:space="preserve">On demande s’il eſt plus avantageux de n’avoir à faire qu’à un <lb/>ſeul Entrepreneur general, qu’à pluſieurs qui ſeroient chargés de dif-<lb/>ferentes eſpeces d’ouvrages. </s> <s xml:id="echoid-s13286" xml:space="preserve">L’un & </s> <s xml:id="echoid-s13287" xml:space="preserve">l’autre peut avoir lieu, comme <lb/>cela arrive quelquefois. </s> <s xml:id="echoid-s13288" xml:space="preserve">Cependant, il convient mieux qu’un ſeul <lb/>en ſoit chargé; </s> <s xml:id="echoid-s13289" xml:space="preserve">& </s> <s xml:id="echoid-s13290" xml:space="preserve">pluſieurs raiſons ſemblent autoriſer mon ſenti-<lb/>ment.</s> <s xml:id="echoid-s13291" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13292" xml:space="preserve">10. </s> <s xml:id="echoid-s13293" xml:space="preserve">Quand tout eſt réüni dans la mème perſonne, le travail ſe <lb/>ſuit mieux, il ſurvient moins de diſcuſſions & </s> <s xml:id="echoid-s13294" xml:space="preserve">de faux-fuyans.</s> <s xml:id="echoid-s13295" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13296" xml:space="preserve">20. </s> <s xml:id="echoid-s13297" xml:space="preserve">Les interêts du Roy ne périclitent pas tant, & </s> <s xml:id="echoid-s13298" xml:space="preserve">il eſt plus aiſé <lb/>de faire des recherches, ſi le cas y échoit.</s> <s xml:id="echoid-s13299" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13300" xml:space="preserve">30. </s> <s xml:id="echoid-s13301" xml:space="preserve">L’Entrepreneur general trouve toûjours lui-même des gens <lb/>ſolvables & </s> <s xml:id="echoid-s13302" xml:space="preserve">capables pour ſoutraiter avec lui; </s> <s xml:id="echoid-s13303" xml:space="preserve">& </s> <s xml:id="echoid-s13304" xml:space="preserve">enfin dans les diffe- <pb o="50" file="0600" n="652" rhead="LA SCIENCE DES INGENIEURS,"/> rentes manœuvres qui ſurviennent, on ſçait d’abord à qui s’adreſſer, <lb/>& </s> <s xml:id="echoid-s13305" xml:space="preserve">ſur qui cela doit rouler, ſans être expoſé aux mauvais procedés <lb/>qui arrivent ſouvent, quand pluſieurs Entrepreneurs s’en mêlent. <lb/></s> <s xml:id="echoid-s13306" xml:space="preserve">Ainſi, il n’y a point à balancer dans ce choix; </s> <s xml:id="echoid-s13307" xml:space="preserve">& </s> <s xml:id="echoid-s13308" xml:space="preserve">il eſt même d’uſage <lb/>dans une groſſe entrepriſe de donner le tout à celui qui eſt chargé <lb/>des plus gros ouvrages, quand même il s’en ſeroit trouvé d’autres <lb/>qui euſſent détaché quelque choſe: </s> <s xml:id="echoid-s13309" xml:space="preserve">mais auſſi l’Entrepreneur ge-<lb/>neral ne peut exiger que le prix des miſes qui auront été faites.</s> <s xml:id="echoid-s13310" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div673" type="section" level="1" n="173"> <head xml:id="echoid-head391" xml:space="preserve">AVERTISSEMENT.</head> <p style="it"> <s xml:id="echoid-s13311" xml:space="preserve">VOici le Devis des Cazernes de Bethune, relatif aux Deſſeins de <lb/>la trentiéme Planche, tel qu’il m’a été envoyé par M. </s> <s xml:id="echoid-s13312" xml:space="preserve">Darte-<lb/>zay qui étoit alors Ingenieur en chef de cette Place. </s> <s xml:id="echoid-s13313" xml:space="preserve">Comme ce Devis <lb/>eſt fort ample & </s> <s xml:id="echoid-s13314" xml:space="preserve">très inſtructif, on y trouvera quantité de détails, dont <lb/>il n’a pas été fait mention dans les autres précédens. </s> <s xml:id="echoid-s13315" xml:space="preserve">Il y a quelques <lb/>endroits qui auroient eu beſoin d’être retouchés, pour rendre le Stile plus <lb/>net; </s> <s xml:id="echoid-s13316" xml:space="preserve">& </s> <s xml:id="echoid-s13317" xml:space="preserve">ſans doute que M. </s> <s xml:id="echoid-s13318" xml:space="preserve">Dartezay l’auroit fait avec plaiſir, s’il avoit <lb/>eu le tems de le repaſſer: </s> <s xml:id="echoid-s13319" xml:space="preserve">mais comme l’Impreſſion de mon Livre étoit <lb/>fort avancée, quand je le lui ai demandé, c’eſt à moi qu’on doit s’en <lb/>prendre, & </s> <s xml:id="echoid-s13320" xml:space="preserve">non pas à lui. </s> <s xml:id="echoid-s13321" xml:space="preserve">F’ajoûterai, que ce Devis étoit accompa-<lb/>gné d’un autre pour la Citerne qui a été conſtruite ſous le même Bâti-<lb/>ment, que j’ai ſupprimé, parce que rapportant celui de la grande Ci-<lb/>terne de Calais, il étoit inutile de multiplier les êtres ſans néceſſité.</s> <s xml:id="echoid-s13322" xml:space="preserve"/> </p> <figure> <image file="0600-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/xxxxxxxx/figures/0600-01"/> </figure> <pb o="51" file="0601" n="653" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> </div> <div xml:id="echoid-div674" type="section" level="1" n="174"> <head xml:id="echoid-head392" xml:space="preserve">DEVIS ET CONDITIONS QU’OBSERVERONT <lb/>les Entrepreneurs des Cazernes ordonnées <lb/>à faire à Bethune.</head> <head xml:id="echoid-head393" xml:space="preserve"><emph style="sc">Premierement</emph>.</head> <p> <s xml:id="echoid-s13323" xml:space="preserve">L Es terres pour les fondemens ſeront enlevées & </s> <s xml:id="echoid-s13324" xml:space="preserve">poſées dans <lb/> <anchor type="note" xlink:label="note-0601-01a" xlink:href="note-0601-01"/> les lieux indiqués, conformement aux alignemens & </s> <s xml:id="echoid-s13325" xml:space="preserve">piquers <lb/>de hauteur qui ſeront donnés, pour relever le terrain autant qu’il <lb/>ſera jugé convenir par l’Ingenieur-Directeur, ou celuien chef, pour <lb/>remplir les trous, & </s> <s xml:id="echoid-s13326" xml:space="preserve">mettre à hauteur les ruës quiy communiquent, <lb/>afin de rendre le terrain bien uni, avec les pentes d’eau néceſſai-<lb/>res, obſervant de les arranger & </s> <s xml:id="echoid-s13327" xml:space="preserve">dreſſer par lits dans toute l’éten-<lb/>duë qu’elles devront occuper, & </s> <s xml:id="echoid-s13328" xml:space="preserve">de les bien battre avec des dames <lb/>ou maſſes de bois; </s> <s xml:id="echoid-s13329" xml:space="preserve">& </s> <s xml:id="echoid-s13330" xml:space="preserve">s’il s’en trouve trop, l’Entrepreneur les fera <lb/>porter hors la Ville aux endroits qui lui ſeront marqués; </s> <s xml:id="echoid-s13331" xml:space="preserve">& </s> <s xml:id="echoid-s13332" xml:space="preserve">quand <lb/>il s’en trouvera de mal miſes, il ſera obligé de les ôter, & </s> <s xml:id="echoid-s13333" xml:space="preserve">rétablir <lb/>à ſes frais.</s> <s xml:id="echoid-s13334" xml:space="preserve"/> </p> <div xml:id="echoid-div674" type="float" level="2" n="1"> <note position="right" xlink:label="note-0601-01" xlink:href="note-0601-01a" xml:space="preserve">Terres.</note> </div> <p> <s xml:id="echoid-s13335" xml:space="preserve">Ces terres ſeront meſurées & </s> <s xml:id="echoid-s13336" xml:space="preserve">reduites à la toiſe cube dans les <lb/>lieux de leur déblai, & </s> <s xml:id="echoid-s13337" xml:space="preserve">payées au pris de l’adjudication.</s> <s xml:id="echoid-s13338" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div676" type="section" level="1" n="175"> <head xml:id="echoid-head394" xml:space="preserve">II.</head> <p> <s xml:id="echoid-s13339" xml:space="preserve">L’excavation faite en profondeur ſuffiſante, & </s> <s xml:id="echoid-s13340" xml:space="preserve">le fond reconnu <lb/> <anchor type="note" xlink:label="note-0601-02a" xlink:href="note-0601-02"/> bon par l’Ingenieur, il ſera applani bien de niveau; </s> <s xml:id="echoid-s13341" xml:space="preserve">après que les ali-<lb/>gnemens auront été verifiés, on y commencera la maçonnerie <lb/>en libage & </s> <s xml:id="echoid-s13342" xml:space="preserve">gros moëlon juſqu’à un pied au deſſous du rez, la <lb/>quelle aura de largeur ou d’empatement, ſçavoir, le pignon qui <lb/>regarde la Ville, & </s> <s xml:id="echoid-s13343" xml:space="preserve">la partie du mur de face qui regarde le rem-<lb/>part des deux bouts qui doivent butter les voûtes des écuries, cinq <lb/>pieds huit pouces juſqu’à la premiere retraite, cinq pieds quatre <lb/>pouces pour la deuxiéme, & </s> <s xml:id="echoid-s13344" xml:space="preserve">cinq pieds en nette maçonnerie.</s> <s xml:id="echoid-s13345" xml:space="preserve"/> </p> <div xml:id="echoid-div676" type="float" level="2" n="1"> <note position="right" xlink:label="note-0601-02" xlink:href="note-0601-02a" xml:space="preserve">Maçonne-<lb/>rie des fon-<lb/>demens.</note> </div> <p> <s xml:id="echoid-s13346" xml:space="preserve">Le pignon qui regarde le Château, trois pieds quatre pouces juſ-<lb/>qu’à la premiere retraite, trois pieds pour la deuxiéme, & </s> <s xml:id="echoid-s13347" xml:space="preserve">deux <lb/>pieds huit pouces en nette maçonnerie.</s> <s xml:id="echoid-s13348" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13349" xml:space="preserve">Les murs de faces, trois pieds deux pouces juſqu’à la premiere <lb/>retraite, deux pieds dix pouces pour la deuxiéme, & </s> <s xml:id="echoid-s13350" xml:space="preserve">deux pieds <lb/>ſix pouces en nette maçonnerie.</s> <s xml:id="echoid-s13351" xml:space="preserve"/> </p> <pb o="52" file="0602" n="654" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s13352" xml:space="preserve">Ceux de refends qui doivent contenir les cheminées, & </s> <s xml:id="echoid-s13353" xml:space="preserve">l’entre-<lb/>fends qui traverſe en long les écuries dans le milieu du bâtiment <lb/>au quartier des ſoldats, trois pieds juſqu’à la premiere retraite, <lb/>deux pieds huit pouces pour la deuxiéme, & </s> <s xml:id="echoid-s13354" xml:space="preserve">deux pieds quatre <lb/>pouces, ou trois briques & </s> <s xml:id="echoid-s13355" xml:space="preserve">demie de huit pouces en nette maçon-<lb/>nerie.</s> <s xml:id="echoid-s13356" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13357" xml:space="preserve">Les dix contreforts des cinq angles, de cinq pieds juſqu’à la pre-<lb/>miere retraite, quatre pieds huit pouces pour la deuxiéme, & </s> <s xml:id="echoid-s13358" xml:space="preserve">qua-<lb/>tre pieds quatre pouces en nette maçonnerie.</s> <s xml:id="echoid-s13359" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13360" xml:space="preserve">Les autres murs qui font la cage des deux eſcaliers, de deux pieds <lb/>quatre pouces juſqu’à la premiere retraite, deux pieds pour la deu-<lb/>xiéme, & </s> <s xml:id="echoid-s13361" xml:space="preserve">un pied huit pouces, ou deux briques & </s> <s xml:id="echoid-s13362" xml:space="preserve">demie en net-<lb/>te maçonnerie.</s> <s xml:id="echoid-s13363" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13364" xml:space="preserve">Le mur d’échiffe au quartier des ſoldats, d’un pied huit pouces <lb/>juſqu’à la premiere retraite, un pied quatre pouces pour la deu-<lb/>xiéme, & </s> <s xml:id="echoid-s13365" xml:space="preserve">un pied, ou brique & </s> <s xml:id="echoid-s13366" xml:space="preserve">demie en nette maçonnerie.</s> <s xml:id="echoid-s13367" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13368" xml:space="preserve">Les deux murs d’entrefends pour le corridor au quartier des Offi-<lb/>ciers, deux pieds juſqu’à la premiere retraite, un pied huit pouces <lb/>pour la deuxiéme, & </s> <s xml:id="echoid-s13369" xml:space="preserve">un pied quatre pouces en nette maçonnerie.</s> <s xml:id="echoid-s13370" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13371" xml:space="preserve">Le mur qui ſepare le quatrier des Officiers de celui des Soldats <lb/>deux pieds juſqu’à la premiere retraite, un pied huit pouces pour <lb/>la deuxiéme, & </s> <s xml:id="echoid-s13372" xml:space="preserve">un pied quatre pouces ou deux briques en nette <lb/>maçonnerie.</s> <s xml:id="echoid-s13373" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13374" xml:space="preserve">Et l’autre murtraverſant les deux dernieres écuries, de trois pieds <lb/>juſqu’à la premiere retraite, deux pieds huit pouces pour la deu-<lb/>xiéme, & </s> <s xml:id="echoid-s13375" xml:space="preserve">deux pieds, quatre ou trois briques & </s> <s xml:id="echoid-s13376" xml:space="preserve">demie en nette <lb/>maçonnerie.</s> <s xml:id="echoid-s13377" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13378" xml:space="preserve">Les parties, qui ſe trouveront plus baſſes que ſix à ſept pieds, au-<lb/>ront une augmentation d’épaiſſeur, à raiſon de quatre pouces par <lb/>retraite ſur deux pieds & </s> <s xml:id="echoid-s13379" xml:space="preserve">demi de hauteur; </s> <s xml:id="echoid-s13380" xml:space="preserve">& </s> <s xml:id="echoid-s13381" xml:space="preserve">ſi l’on rencontre le <lb/>ſable boüillant, on diligentera les fondemens en les découvrant, <lb/>lui donnant toute l’épaiſſeur, ou empatement, qu’on croira néceſ-<lb/>ſaire, qui ſera toûjours réduit en nette maçonnerie aux épaiſſeurs <lb/>dites ci-deſſus juſqu’au plancher du premier étage.</s> <s xml:id="echoid-s13382" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13383" xml:space="preserve">Les murs des latrines ſeront de même conſtruction que ceux des <lb/>faces des bâtimens.</s> <s xml:id="echoid-s13384" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13385" xml:space="preserve">Puis après avoir élevé trois rangs de brique bien de niveau, fai-<lb/>ſant chaîne ſur toute l’épaiſſeur de ces murs, & </s> <s xml:id="echoid-s13386" xml:space="preserve">verifié de nouveau <lb/>les alignemens & </s> <s xml:id="echoid-s13387" xml:space="preserve">les angles, on y poſera une graiſſerie ſervant de <lb/>baſe en dehors, laquelle aura trois pieds de hauteur, où l’on laiſ-<lb/>ſera un chanfrain de deux pouces coupé en glacis, qui fera une <lb/>retraite.</s> <s xml:id="echoid-s13388" xml:space="preserve"/> </p> <pb o="53" file="0603" n="655" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s13389" xml:space="preserve">La même graiſſerie ſera continuée en dedans des écuries pour la <lb/>conſervation des murs, il en ſera pareillement des pilaſtres des an-<lb/>gles, ou encognures du rez-de-chauſſée, qui feront un avant-corps <lb/>de deux pouces de ſaillie; </s> <s xml:id="echoid-s13390" xml:space="preserve">des pieds droits, ou jambages des fe-<lb/>nêtres & </s> <s xml:id="echoid-s13391" xml:space="preserve">portes, leſquels ſeront élevés juſqu’à la hauteur de ſept <lb/>pieds, obſervant les ébraſemens & </s> <s xml:id="echoid-s13392" xml:space="preserve">battées ſuivant l’uſage.</s> <s xml:id="echoid-s13393" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13394" xml:space="preserve">Les appuis des fenêtres, les ſeüils des portes en dehors, les pre-<lb/>mieres marches, ſeront auſſi de grès d’une ſeule pierre, le tout <lb/>proprement piqué conformement au modele du nouveau Pavil-<lb/>lon de ſaint Prix; </s> <s xml:id="echoid-s13395" xml:space="preserve">les marches de l’eſcalier au quartier des ſol-<lb/>dats, auſſi d’une ſeule pierre, ſeront débrutties, & </s> <s xml:id="echoid-s13396" xml:space="preserve">miſes en œuvre <lb/>à joints quarrés & </s> <s xml:id="echoid-s13397" xml:space="preserve">recouverts; </s> <s xml:id="echoid-s13398" xml:space="preserve">elles auront douze pouces de giron <lb/>ſur ſix de hauteur, à porter dans les murs de trois à quatre pouces <lb/>de chaque côté, ce qui fera quatre pieds deux pouces de longueur <lb/>totale ou environ, ſans défauts, ni défectuoſités vicieuſes; </s> <s xml:id="echoid-s13399" xml:space="preserve">après <lb/>quoi l’on achevera de même façon les angles, les portes, les fenê-<lb/>tres, les cordons à chaque étage, les entablemens, & </s> <s xml:id="echoid-s13400" xml:space="preserve">les ſouches <lb/>des cheminées au-deſſus des toits, en pierres blanches, ainſi que <lb/>les ornemens qu’on laiſſera en attente de ſculpture.</s> <s xml:id="echoid-s13401" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13402" xml:space="preserve">Le reſte de la maçonnerie ſera fait en brique depuis le deſſus de <lb/>la graiſſerie, ainſi que les voûtes des écuries, & </s> <s xml:id="echoid-s13403" xml:space="preserve">celles des eſcaliers <lb/>au quartier des ſoldats.</s> <s xml:id="echoid-s13404" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13405" xml:space="preserve">On gardera bien exactement les diſtributions des chambres & </s> <s xml:id="echoid-s13406" xml:space="preserve">écu-<lb/>ries, & </s> <s xml:id="echoid-s13407" xml:space="preserve">les décorations ſuivant les deſſeins, plans, & </s> <s xml:id="echoid-s13408" xml:space="preserve">profils qui ſeront <lb/>donnez à l’Entrepreneur, ainſi que les retraites, ſçavoir au pre-<lb/>mier étage, le pignon & </s> <s xml:id="echoid-s13409" xml:space="preserve">la partie de mur de face, qui butteront les <lb/>deux bouts des voutes des écuries, ſeront réduits à la même epaiſ-<lb/>ſeur, & </s> <s xml:id="echoid-s13410" xml:space="preserve">tout ainſi que les autres murs de même nature diminuent <lb/>une demie brique, de ſorte que les deux pignons auront ſeulement <lb/>deux pieds quatre pouces, ou trois briques & </s> <s xml:id="echoid-s13411" xml:space="preserve">demie d’épaiſſeur, <lb/>les murs de faces deux pieds ou trois briques, ceux des cordons au <lb/>quartier des Officiers, & </s> <s xml:id="echoid-s13412" xml:space="preserve">à celui des ſoldats au deſſus des voûtes <lb/>des écuries; </s> <s xml:id="echoid-s13413" xml:space="preserve">les murs qui font la cage des eſcaliers, & </s> <s xml:id="echoid-s13414" xml:space="preserve">celui qui ſe-<lb/>pare les deux quartiers, ſeront reduits à un pied ou une brique & </s> <s xml:id="echoid-s13415" xml:space="preserve"><lb/>demie depuis le premier étage juſqu’à leur hauteur totale.</s> <s xml:id="echoid-s13416" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13417" xml:space="preserve">Les murs de refends, qui contiennent les cheminées, leſquelles <lb/>ſeront dévoyées à côté l’une de l’autre dans l’épaiſſeur des murs <lb/>du bas en haut, ne peuvent ſouffrir de reduction.</s> <s xml:id="echoid-s13418" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13419" xml:space="preserve">Tous les autres murs diminuëront de quatre pouces à chaque <lb/>étage.</s> <s xml:id="echoid-s13420" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13421" xml:space="preserve">Le bâtiment des latrines ſera de même conſtruction, & </s> <s xml:id="echoid-s13422" xml:space="preserve">des di- <pb o="54" file="0604" n="656" rhead="LA SCIENCE DES INGENIEURS,"/> menſions des murs de face, dont les voûtes en plein ceintre auront <lb/>les ouvertures néceſſaires pour le paſſage des matieres, le fond pa-<lb/>vé de grès avec une décharge dans la riviere.</s> <s xml:id="echoid-s13423" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13424" xml:space="preserve">Les chambres du rez auront onze pieds de hauteur, lesautres des <lb/>étages au deſſus dix, non compris l’épaiſſeur des planchers, les ga-<lb/>letas auront auſſi dix pieds d’élevation juſques ſous les entraits, <lb/>tous leſquels planchers ſeront compaſſés, de ſorte que l’appui des <lb/>fenêtres & </s> <s xml:id="echoid-s13425" xml:space="preserve">l’entablement ſe trouvent à trois pieds de hauteur au <lb/>deſſus tout au plus.</s> <s xml:id="echoid-s13426" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13427" xml:space="preserve">Les murs du dedansen general ſeront élevés bien à plomb; </s> <s xml:id="echoid-s13428" xml:space="preserve">& </s> <s xml:id="echoid-s13429" xml:space="preserve">ceux <lb/>qui font face auront environ un pouce & </s> <s xml:id="echoid-s13430" xml:space="preserve">demi de fruit en dehors.</s> <s xml:id="echoid-s13431" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13432" xml:space="preserve">Les materiaux pour la conſtruction de ces choſes, ſeront bons, <lb/> <anchor type="note" xlink:label="note-0604-01a" xlink:href="note-0604-01"/> bien choiſis, conditionnés, & </s> <s xml:id="echoid-s13433" xml:space="preserve">de l’échantillon ordinaire, les blancs <lb/>ou gros libages pour les fondemens, provenans des carrieres de la <lb/>Buſſiere ou de Barloüin, tirés au moins d’un an, en bonne ſaiſon, <lb/>il en ſera de même des grès dont les boutiſſes dans les murs auront <lb/>dix-huit à vingt pouces de queuë, eſpacés de trois en trois pieds <lb/>de milieu en milieu en dedans & </s> <s xml:id="echoid-s13434" xml:space="preserve">en dehors alternativement, & </s> <s xml:id="echoid-s13435" xml:space="preserve">les <lb/>panereſſes ou carreaux dix à douze.</s> <s xml:id="echoid-s13436" xml:space="preserve"/> </p> <div xml:id="echoid-div677" type="float" level="2" n="2"> <note position="left" xlink:label="note-0604-01" xlink:href="note-0604-01a" xml:space="preserve">Qualité des <lb/>materiaux.</note> </div> <p> <s xml:id="echoid-s13437" xml:space="preserve">Les pierres de taille pour les pilaſtres desangles, les pieds droits, <lb/>les ouvertures, les cordons, les entablemens, les fenêtres du gale-<lb/>tas, & </s> <s xml:id="echoid-s13438" xml:space="preserve">les ornemens des ſouches des cheminées, ſeront auſſi tirées <lb/>au moins d’un an, en bonne ſaiſon, ayant été expoſées aux injures <lb/>de l’hyver, bien ébouſinées juſqu’au vif, en ſorte qu’il n’y reſte ni <lb/>fil, ni moye, ni veines jaunes, proprement taillées & </s> <s xml:id="echoid-s13439" xml:space="preserve">ragrées au fer <lb/>ſuivant les panneaux & </s> <s xml:id="echoid-s13440" xml:space="preserve">deſſeins qui enſeigneront auſſi les ſaillies <lb/>qu’elles devront avoir.</s> <s xml:id="echoid-s13441" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13442" xml:space="preserve">Les briques ſeront toutes de même échantillon ordinaire, bien <lb/>cuites & </s> <s xml:id="echoid-s13443" xml:space="preserve">bien conditionnées, dont on choiſira les plus belles pour <lb/>les paremens, poſées en bain flotant de mortier, de même que les <lb/>pierres de taille, avec attention de les placer dans leur lit, ainſi <lb/>que la graiſſerie, le tout par aſſiſes égales de niveau & </s> <s xml:id="echoid-s13444" xml:space="preserve">en liaiſon, <lb/>bien & </s> <s xml:id="echoid-s13445" xml:space="preserve">dûëment frottées, reparées, & </s> <s xml:id="echoid-s13446" xml:space="preserve">dans les joints, recirées au <lb/>fer à meſure que le travail avancera, obſervant de les bien appa-<lb/>reiller; </s> <s xml:id="echoid-s13447" xml:space="preserve">principalement les pierres de taille, & </s> <s xml:id="echoid-s13448" xml:space="preserve">les graiſſeries join-<lb/>toyées au mortier de cendrée.</s> <s xml:id="echoid-s13449" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13450" xml:space="preserve">Dans les grandes chaleurs on aura ſoin de moüiller en employant <lb/>chaque brique, afin qu’elles ne refuſent pas le mortier.</s> <s xml:id="echoid-s13451" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13452" xml:space="preserve">L’Entrepreneur ne commencera à travailler à tous ces ouvra-<lb/>ges, qu’après que les attachemens des fondemens lui auront été <lb/>marqués par l’Ingenieur.</s> <s xml:id="echoid-s13453" xml:space="preserve"/> </p> <pb o="55" file="0605" n="657" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s13454" xml:space="preserve">Cette maçonnerie ſera meſurée & </s> <s xml:id="echoid-s13455" xml:space="preserve">réduite à la toiſe cube pourles <lb/>fondemens, & </s> <s xml:id="echoid-s13456" xml:space="preserve">celle au-deſſus à la toiſe quarrée d’une brique d’e-<lb/>paiſſeur ſuivant l’uſage du lieu, toiſée tant plein que vuide, ſans <lb/>rien diminuer des ouvertures.</s> <s xml:id="echoid-s13457" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13458" xml:space="preserve">La graiſſerie comptée au cent de pieds quarrés, meſurée pare-<lb/>mens vûs pour la taille ainſi que les pierres blanches. <lb/></s> <s xml:id="echoid-s13459" xml:space="preserve">Les appuis des fenêtres & </s> <s xml:id="echoid-s13460" xml:space="preserve">les marches à la piece, miſes en place, <lb/>leſquelles choſes ſeront payées au prix de l’adjudication.</s> <s xml:id="echoid-s13461" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div679" type="section" level="1" n="176"> <head xml:id="echoid-head395" xml:space="preserve">III.</head> <p> <s xml:id="echoid-s13462" xml:space="preserve">Le mortier, qu’on employera pour toutes ces maçonneries, ſera <lb/>compoſé d’un tiers de chaux vive de bonne qualité & </s> <s xml:id="echoid-s13463" xml:space="preserve">cuiſſon, ſans <lb/>biſcuit, & </s> <s xml:id="echoid-s13464" xml:space="preserve">non éventée, bien éteinte, & </s> <s xml:id="echoid-s13465" xml:space="preserve">de deux tiers de ſable pur <lb/>du meilleur des environs, criant à la main; </s> <s xml:id="echoid-s13466" xml:space="preserve">il ſera doſé en preſence <lb/>d’un Ingenieur, & </s> <s xml:id="echoid-s13467" xml:space="preserve">on ne l’employera que trois jours au moins après <lb/>qu’ilaura été bien battu, conroyé, & </s> <s xml:id="echoid-s13468" xml:space="preserve">broyé de façon qu’on ne puiſſe <lb/>plus diſtinguer la chaux d’avec le ſable; </s> <s xml:id="echoid-s13469" xml:space="preserve">& </s> <s xml:id="echoid-s13470" xml:space="preserve">que l’un & </s> <s xml:id="echoid-s13471" xml:space="preserve">l’autre étant <lb/>confondus ne faſſent plus qu’un même corps.</s> <s xml:id="echoid-s13472" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13473" xml:space="preserve">Celui dont on ſe ſervira pour les grès en paremens, encognures <lb/>& </s> <s xml:id="echoid-s13474" xml:space="preserve">autres, ſera compoſé d’un tiers de chaux vive, & </s> <s xml:id="echoid-s13475" xml:space="preserve">de deux tiers <lb/>de bonne cendrée, façonné comme il vient d’être dit, n’y mettant <lb/>qu’une fois de l’eau; </s> <s xml:id="echoid-s13476" xml:space="preserve">puis étant rebattu pendant pluſieurs jours, il <lb/>ſera employé tout frais battu autant que faire ſe pourra.</s> <s xml:id="echoid-s13477" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div680" type="section" level="1" n="177"> <head xml:id="echoid-head396" xml:space="preserve">IV.</head> <p> <s xml:id="echoid-s13478" xml:space="preserve">Le pavé de grès pour la ruë qui communique à ces Cazernes, <lb/>pour la bande qu’on ſe propoſe tout autour, celui des cours, &</s> <s xml:id="echoid-s13479" xml:space="preserve">c. <lb/></s> <s xml:id="echoid-s13480" xml:space="preserve">ſera du meilleur du pays, d’une dure & </s> <s xml:id="echoid-s13481" xml:space="preserve">bonne qualité; </s> <s xml:id="echoid-s13482" xml:space="preserve">il aura ſix <lb/>à ſept pouces de tête ſur huit à neuf de queuë, de figure preſque <lb/>cubique; </s> <s xml:id="echoid-s13483" xml:space="preserve">& </s> <s xml:id="echoid-s13484" xml:space="preserve">les bourdures, de dix-huit pouces ſur huit à neuf de lar-<lb/>ge, & </s> <s xml:id="echoid-s13485" xml:space="preserve">au moins douze de long, ſeront de même quarré ſur les deux <lb/>bouts; </s> <s xml:id="echoid-s13486" xml:space="preserve">il ſera appareillé & </s> <s xml:id="echoid-s13487" xml:space="preserve">par routes égales, en liaiſon, ſur un lit <lb/>ou forme de ſable de neuf pouces de hauteur, battu & </s> <s xml:id="echoid-s13488" xml:space="preserve">affermi au <lb/>refus de la damoiſelle, obſervant les pentes & </s> <s xml:id="echoid-s13489" xml:space="preserve">bombages qui ſeront <lb/>reglés.</s> <s xml:id="echoid-s13490" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13491" xml:space="preserve">La même choſe ſe pratiquera pourle pavé à relever, & </s> <s xml:id="echoid-s13492" xml:space="preserve">ils ſeront <lb/>tous meſurés à la toiſe quarrée, payés au prix de l’adjudication, <lb/>bordures compriſes.</s> <s xml:id="echoid-s13493" xml:space="preserve"/> </p> <pb o="56" file="0606" n="658" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div681" type="section" level="1" n="178"> <head xml:id="echoid-head397" xml:space="preserve">V.</head> <p> <s xml:id="echoid-s13494" xml:space="preserve">Toutes les charpentes, qui ſe trouveront à faire pour la conſtruc-<lb/>tion de ces Cazernes, ſeront executées ſuivant le Memoire ci-joint, <lb/>& </s> <s xml:id="echoid-s13495" xml:space="preserve">les deſſeins qui ſeront donnés à l’Entrepreneur pour les longeurs, <lb/>façons, & </s> <s xml:id="echoid-s13496" xml:space="preserve">poſitions des bois, qu’il ſuivra de point en point, ſans y <lb/>pouvoir rien changer; </s> <s xml:id="echoid-s13497" xml:space="preserve">tous leſquels bois ſeront bien ſains & </s> <s xml:id="echoid-s13498" xml:space="preserve">ſecs, <lb/>coupés au moins de deux ans, & </s> <s xml:id="echoid-s13499" xml:space="preserve">abbatus en bonne ſaiſon, à vive <lb/>arête, à l’exception des ſommiers auſquels on pourra laiſſer deux <lb/>petits chanfrains d’un pouce & </s> <s xml:id="echoid-s13500" xml:space="preserve">demi aux angles du deſſous, les po-<lb/>ſant toûjours de cant, & </s> <s xml:id="echoid-s13501" xml:space="preserve">leur bombage en deſſus, mais les angles <lb/>du deſſus à vive arête; </s> <s xml:id="echoid-s13502" xml:space="preserve">toutes leſquelles charpentes ſans aubier, ca-<lb/>pelures, ventelures, ni mauvais nœuds, ſeront miſes en œuvre, <lb/>aſſemblées à abreuvement, tenons, & </s> <s xml:id="echoid-s13503" xml:space="preserve">mortoiſes avec toute la juſteſſe, <lb/>ſolidité, & </s> <s xml:id="echoid-s13504" xml:space="preserve">propreté poſſible, & </s> <s xml:id="echoid-s13505" xml:space="preserve">bien chevillées; </s> <s xml:id="echoid-s13506" xml:space="preserve">& </s> <s xml:id="echoid-s13507" xml:space="preserve">au cas que l’En-<lb/>trepreneur livre des pieces plus groſſes, elles ne lui ſeront meſurées <lb/>que ſuivant leſdits deſſeins & </s> <s xml:id="echoid-s13508" xml:space="preserve">memoires.</s> <s xml:id="echoid-s13509" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13510" xml:space="preserve">L’Entrepreneur ſera obligé de faire, à toutes les marches maſſives <lb/>de l’eſcalier au quartier des Officiers, une aſtragale avec une mou-<lb/>lûre pouſſée de deux pouces, & </s> <s xml:id="echoid-s13511" xml:space="preserve">de faire auſſi tourner au tour, ſui-<lb/>vant un deſſein approuvé pour ſervir de modéle, les poteaux & </s> <s xml:id="echoid-s13512" xml:space="preserve"><lb/>potelets qui y ſeront employés.</s> <s xml:id="echoid-s13513" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13514" xml:space="preserve">Les premiers limons des deux eſcaliers au même lieu ſeront pla-<lb/>cés ſur chacun une marche maſſive d’épaiſſeur & </s> <s xml:id="echoid-s13515" xml:space="preserve">longueur ſuffi-<lb/>ſante pour être arondie en dehors; </s> <s xml:id="echoid-s13516" xml:space="preserve">dans tous leſquels limons en <lb/>general on aſſemblera ces marches, & </s> <s xml:id="echoid-s13517" xml:space="preserve">ils n’auront d’autres orne-<lb/>mens que l’arête du deſſous arondie entre deux petites moulûres.</s> <s xml:id="echoid-s13518" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div682" type="section" level="1" n="179"> <head xml:id="echoid-head398" style="it" xml:space="preserve">MEMOIRE POVR SERVIR A LA DISTRIBVTION <lb/>des Bois employés aux Cazernes de S. Jor, détaillés par étage.</head> <head xml:id="echoid-head399" xml:space="preserve"><emph style="sc">Les</emph> <emph style="sc">Bois du</emph> <emph style="sc">Rez</emph>.</head> <note position="right" xml:space="preserve"> <lb/>Les ſupports mis en attente dans les murs pour porter # Groſſeurs. <lb/>les auges des écuries, # 8. & 4. <lb/>Idem. Ceux du deſſous des auges, # 6. & 4. <lb/>Idem. Ceux pour les rateliers, # 4. & 4. <lb/>Les pieces de bois, ou linteaux encaſtrés dans les murs <lb/>des huit Chambres d’Officiers, pour ſervir de porte-<lb/>manteaux, # 6. & 4. <lb/>Les madriers du deſſus des portes en dedans, # 10. & 4. <lb/></note> <pb o="57" file="0607" n="659" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <note position="right" xml:space="preserve"> <lb/>Ceux des fenêtres auſſi en dedans. # 27. & 4. <lb/></note> <note position="right" xml:space="preserve"> <lb/><emph style="sc">Le premier</emph> <emph style="sc">Etage</emph>. # Groſſeur. <lb/>Les huit ſommiers des chambres d’Officiers, # 12. & 10. <lb/>Les ſemelles ou couſſinets ſous ces ſommiers, # 6. & 4. <lb/>Les ſoliveaux des chambres d’Officiers & ceux du coridor, # 6. & 4. <lb/>Les autres ſoliveaux qui portent les jambages des che-<lb/>minées, # 8. & 6. <lb/>Les cours des plattes-formes pour ſervir de tirans an-<lb/>crés dans les murs à chaque étage, # 6. & 4. <lb/>Les linteaux encaſtrés dans les murs des deux quartiers <lb/>à chaque étage, pour ſervir de porte-manteaux, # 6. & 4. <lb/>Les madriers au deſſus des portes en dedans, # 9. & 4. <lb/>Ceux au deſſus des fenêtres des deux pignons, # 17. & 4. <lb/>Les appuis des mêmes, # 6. & 4. <lb/>Les madriers du deſſus des autres fenêtres, # 11. & 4. <lb/>Les appuis des mêmes, # 6. & 4. <lb/>Les pieces de bois qui traverſent les murs de refends, <lb/>pour porter ſur les jambages les ceintres des cheminées, <lb/>& ſervir à tenir les chambranles, # 4. & 4. <lb/>Les chaſſis des portes au quartier des ſoldats, # 14. & 6. <lb/></note> <note position="right" xml:space="preserve"> <lb/><emph style="sc">Le deuxie’me</emph> <emph style="sc">Etage</emph>. # Groſſeur. <lb/>Les huit ſommiers du quartier des Officiers, & neuf à <lb/>celui des ſoldats, # 12. & 10. <lb/>Trois autres dans la premiere chambre joignant la ci-<lb/>terne, & celle dans l’angle qui la ſuit, # 14. & 12. <lb/>Les ſemelles ou couſſinets pour les mêmes, # 6. & 4. <lb/>Les ſoliveaux pour les hauſſes des eſcaliers au quar-<lb/>tier des Officiers, & ceux qui portent les jambages des <lb/>cheminées aux deux quartiers, # 8. & 6. <lb/>Les autres ſoliveaux des planchers des deux quartiers, # 6. & 4. <lb/>Les pieces traverſant les murs de refends, pour por-<lb/>ter les ceintres des cheminées aux deux quartiers, # 4. & 4. <lb/>Les chaſſis des portes au quartier des ſoldats, # 14. & 6. <lb/>Les madriers pour le deſſus en dedans des fenêtres <lb/>des pignons, # 13. & 4. <lb/>Ceux des appuis des mêmes, # 6. & 4. <lb/>Les madriers pour le deſſus en dedans des autres fenê-<lb/>tres, # 8. & 4. <lb/>Les appuis des mêmes, # 6. & 4. <lb/></note> <pb o="58" file="0608" n="660" rhead="LA SCIENCE DES INGENIEURS,"/> <note position="right" xml:space="preserve"> <lb/>Les madriers du deſſus des portes des chambres d’Offi-<lb/>ciers en dedans, # 6. & 4. <lb/></note> </div> <div xml:id="echoid-div683" type="section" level="1" n="180"> <head xml:id="echoid-head400" xml:space="preserve"><emph style="sc">Le troisie’me</emph> <emph style="sc">Etage ou</emph> <emph style="sc">Galetas</emph>.</head> <note position="right" xml:space="preserve"> <lb/># Groſſeur. <lb/>Les huit ſommiers du quartier des Officiers, & quatre <lb/>aux chambres du côté du pignon qui regarde la Ville, <lb/>à celui des ſoldats, # 12. & 10. <lb/>Dix-huit autres ſommiers aux chambres du pan cou-<lb/>pé, & autres le long de la face qui regarde le rempart, <lb/>& ceux qui ſoutiennent la manſarde, # 14. & 12. <lb/>Les ſemelles ou couſſinets en general. # 6. & 4. <lb/>Les ſoliveaux pour les hauſſes des eſcaliers, # 8. & 6. <lb/>Ceux pour porter les jambages des cheminées aux deux <lb/>quartiers, # 8. & 6. <lb/>Les autres pour les planchers des deux quartiers, # 6. & 4. <lb/>Les pieces traverſant les murs pour porter les man-<lb/>teaux des cheminées des deux quartiers, # 4. & 4. <lb/>Les chaſſis des portes au quartier des ſoldats, # 14. & 6. <lb/></note> </div> <div xml:id="echoid-div684" type="section" level="1" n="181"> <head xml:id="echoid-head401" xml:space="preserve"><emph style="sc">Le</emph> <emph style="sc">Comble et le</emph> <emph style="sc">Plancher en dessous</emph>.</head> <note symbol="*" position="left" xml:space="preserve">Les en-<lb/>traits por-<lb/>tent ſur les <lb/>deux murs <lb/>du cori-<lb/>dor, car <lb/>autrement <lb/>il leur fau-<lb/>droit plus <lb/>de groſ-<lb/>ſeur.</note> <note position="right" xml:space="preserve"> <lb/>Cours de pannes de briſis, # 12. & 6. <lb/>Les gouſſets, ou enraînures des angles, # 10. & 8. <lb/>Les jambes de force, les blochets, les entraits<anchor type="note" xlink:href="" symbol="*"/>, ceux des croupes, les arbalêtriers ou petites forces, les poin- çons, les coliers ou enraînures, les arrêtiers ſur les an- gles du faux comble, ſur la panne de briſis, les ſoli- veaux ou gîtes des eſcaliers des deux quartiers, ceux ſervant de liſſoirs le long des ſouches des cheminées, & qui portent les planchers des deux quartiers, # 7. & 6. Cours des ſablieres ou plattes, # 10. & 4. Cours d’autres ſablieres ſur l’entablement, pour por- ter les coyaux au comble des fenêtres, # 6. & 4. Cours de pannes, ou ventrieres au faux comble, fur deux rangs de chaque côté, # 6. & 4. Cours de faîtes & ſous-faîtes, # 6. & 4. Les pieces d’entre-toiſes faiſant les croix de ſaint An- dré entre les faîtes & ſous-faites, les liens ou braſſons des fermes & autres, les plattes-formes ou couſſinets pour toutes les pieces qui portent ſur les murs, # 6. & 4. Les pieces qui portent les jouës des fenêtres du troi- </note> <pb o="59" file="0609" n="661" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <note position="right" xml:space="preserve"> <lb/>ſiéme étage, ou galetas, # 8. & 4. <lb/>Les montans, & les petites pannes, & les appuis des <lb/>petites fenêtres des greniers, # 6. & 4. <lb/>Les ceintres qui font le devant des mêmes, # 10. & 4. <lb/>Les deux chaſſis des portes des greniers ſous le faux <lb/>comble, # 9. & 5. <lb/></note> </div> <div xml:id="echoid-div685" type="section" level="1" n="182"> <head xml:id="echoid-head402" xml:space="preserve"><emph style="sc">Les deux</emph> <emph style="sc">Escaliers au quartier des</emph> <emph style="sc">Officiers</emph>.</head> <note position="right" xml:space="preserve"> <lb/>Les limons, & les patins ſous les deux premiers li-<lb/>mons, # 10. & 5. <lb/>Les cent ſoixante & quatre marches maſſives coupées <lb/>en triangle rectangle, réduits à # 13. & 4. <lb/>Les ſeize pieces traverſant la cage des eſcaliers à l’en-<lb/>droit des palliers & au haut de chaque étage, pour por-<lb/>ter & appuyer les limons, # 10. & 8. <lb/>Les trente-deux grands poteaux, # 5. & 5. <lb/>Les deux cens huit potelets tournés, compris ceux au <lb/>devant des fenêtres, # 4. & 4. <lb/>Les cours d’apui des eſcaliers, & au devant des fenê-<lb/>tres, # 5. & 4. <lb/>Les ſolles au devant des mêmes fenêtres pour porter <lb/>les potelets, # 5. & 4. <lb/>Les ſoliveaux des palliers & autres, # 6. & 4. <lb/></note> </div> <div xml:id="echoid-div686" type="section" level="1" n="183"> <head xml:id="echoid-head403" xml:space="preserve">BOIS D’ORME AU QUATRIEME PLANCHER, <lb/><emph style="sc">ET AU</emph> <emph style="sc">Comblage</emph>.</head> <note position="right" xml:space="preserve"> <lb/>Les ſoliveaux des chambres des deux quartiers & des <lb/>corridors, # 6. & 4. <lb/>Les chevrons, les coyaux, le comblage des fenêtres <lb/>des galetas, & celui des petites lucarnes, # 4. & 3. <lb/>Les ruelles ou linteaux aux mêmes fenêtres, # 3. & 2. <lb/></note> <p> <s xml:id="echoid-s13519" xml:space="preserve">Cette charpente ſera toiſée pour être réduite au cent de ſolives <lb/>ſuivant l’uſage, & </s> <s xml:id="echoid-s13520" xml:space="preserve">payée, ſçavoir le bois de chêne ordinaire à un <lb/>prix, celui des ſommiers de dix pouces d’équarriſſage & </s> <s xml:id="echoid-s13521" xml:space="preserve">au deſſus, <lb/>à un autre, à cauſe de leurs longueurs & </s> <s xml:id="echoid-s13522" xml:space="preserve">groſſeurs, & </s> <s xml:id="echoid-s13523" xml:space="preserve">les bois d’or-<lb/>me des combles auſſi à un prix particulier; </s> <s xml:id="echoid-s13524" xml:space="preserve">les rateliers des écuries <lb/>égaux à ceux des Cazernes de ſaint Prix, à la toiſe courante, moyen-<lb/>nant quoi l’Entrepreneur ſera tenu à tous les ornemens ordinaires <lb/>de la charpente, & </s> <s xml:id="echoid-s13525" xml:space="preserve">au rétabliſſement de toutes ouvertures dans les <pb o="60" file="0610" n="662" rhead="LA SCIENCE DES INGENIEURS,"/> murs & </s> <s xml:id="echoid-s13526" xml:space="preserve">dégradations qu’il ſera obligé de faire pour placer ces bois, <lb/>ou qui ſurviendront par mal-adreſſe.</s> <s xml:id="echoid-s13527" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div687" type="section" level="1" n="184"> <head xml:id="echoid-head404" xml:space="preserve">VI.</head> <p> <s xml:id="echoid-s13528" xml:space="preserve">Les planchers des mangeoirs dans les écuries, ceux des cham-<lb/>bres, des grandes portes d’entrées, de celles des écuries, &</s> <s xml:id="echoid-s13529" xml:space="preserve">c. </s> <s xml:id="echoid-s13530" xml:space="preserve">ſeront <lb/>de bonnes planches d’un pouce franc d’épaiſſeur, bien ſéches, ſans <lb/>défauts, ni nœuds vicieux, miſes en longueur pour porter ſur les <lb/>gîtes, de la même qualité de bois qu’il eſt dit ci-devant, bien join-<lb/>tes & </s> <s xml:id="echoid-s13531" xml:space="preserve">équarries, de ſorte que les bouts de deux planches couvrent <lb/>chacune en ſe joignant, la moitié d’un ſoliveau, parées & </s> <s xml:id="echoid-s13532" xml:space="preserve">rabottées <lb/>des deux côtez, s’il eſt beſoin, aſſemblées à languette & </s> <s xml:id="echoid-s13533" xml:space="preserve">raînure <lb/>pour les portes, & </s> <s xml:id="echoid-s13534" xml:space="preserve">à joints recouverts d’un quart de pouce au moins <lb/>pour les planchers, attachées chacune avec de bons clous ſur cha-<lb/>que gîte ou ſoliveau, de longueur convenable, en quantité ſuffi-<lb/>ſante, & </s> <s xml:id="echoid-s13535" xml:space="preserve">enſoncés à tête perduë.</s> <s xml:id="echoid-s13536" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13537" xml:space="preserve">Cet ouvrage ſera payé à la toiſe quarrée, le chêne neuf à un <lb/>prix, & </s> <s xml:id="echoid-s13538" xml:space="preserve">le bois blanc à un autre, les clous, chevilles, & </s> <s xml:id="echoid-s13539" xml:space="preserve">generale-<lb/>ment tout ce qui en dépendra, compris.</s> <s xml:id="echoid-s13540" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div688" type="section" level="1" n="185"> <head xml:id="echoid-head405" xml:space="preserve">VII.</head> <p> <s xml:id="echoid-s13541" xml:space="preserve">La menuiſerie qui conſiſtera particulierement en entre-deux <lb/>portes au quartier des Officiers, les chambranles des cheminées au <lb/>même lieu, quatre-vingt quatorze croiſées aux deux quartiers, les <lb/>armoires, &</s> <s xml:id="echoid-s13542" xml:space="preserve">c. </s> <s xml:id="echoid-s13543" xml:space="preserve">ſera d’un bois de chêne choiſi, bon & </s> <s xml:id="echoid-s13544" xml:space="preserve">bien ſec, de <lb/>cinq ans au moins, & </s> <s xml:id="echoid-s13545" xml:space="preserve">des qualités expliquées à l’article 5. </s> <s xml:id="echoid-s13546" xml:space="preserve">de la <lb/>Charpente, le tout bien uniformement executé ſuivant les deſſeins; <lb/></s> <s xml:id="echoid-s13547" xml:space="preserve">ſera payé à la piéce, les portes des chambres d’Officiers à un prix, <lb/>celles des écuries & </s> <s xml:id="echoid-s13548" xml:space="preserve">chambres des ſoldats à un autre, les fenêtres à <lb/>un autre, les chambranles ou bas des cheminées auſſi à la piece, & </s> <s xml:id="echoid-s13549" xml:space="preserve"><lb/>le reſte à la toiſe quarrée.</s> <s xml:id="echoid-s13550" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div689" type="section" level="1" n="186"> <head xml:id="echoid-head406" xml:space="preserve">VIII.</head> <p> <s xml:id="echoid-s13551" xml:space="preserve">Les plafonds des galetas ſeront faits de lattes de cœur de chêne, <lb/>ſolidement clouées aux gîtes ou ſoliveaux, ſur leſquelles on appli-<lb/>quera deux couches de mortier, la premiere compoſée d’argile <lb/>avec un huitiéme de chaux vive, dans laquelle on mêlera de la <lb/>bourre qu’on aura eu ſoin de bien battre pour en ôter la pouſſiere, <lb/>repriſe & </s> <s xml:id="echoid-s13552" xml:space="preserve">rendue unie par deſſous; </s> <s xml:id="echoid-s13553" xml:space="preserve">la ſeconde ſera auſſi de chaux <pb o="61" file="0611" n="663" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> ſeulement bien éteinte, coulée, & </s> <s xml:id="echoid-s13554" xml:space="preserve">de bourre blanche battuë en <lb/>quantité ſuffiſante, le tout broyé enſemble; </s> <s xml:id="echoid-s13555" xml:space="preserve">obſervant de faire ces <lb/>mortiers trois ou quatre jours avant que de les employer, & </s> <s xml:id="echoid-s13556" xml:space="preserve">de met-<lb/>tre la ſeconde couche après que la premiere aura été reconnuë ſuf-<lb/>fiſamment ſéche, ſans l’être trop, afin que les deux couches faſſent <lb/>union enſemble.</s> <s xml:id="echoid-s13557" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13558" xml:space="preserve">Cette deuxiéme couche ſera proprement cirée & </s> <s xml:id="echoid-s13559" xml:space="preserve">polie à la truelle <lb/>juſqu’à ce qu’elle ne puiſſe plus fendre, pour enſuite être lavée <lb/>deux fois avec la broſſe d’un lait de chaux vive mêlé de petit bleu.</s> <s xml:id="echoid-s13560" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13561" xml:space="preserve">Cet ouvrage ſera meſuré & </s> <s xml:id="echoid-s13562" xml:space="preserve">payé à la toiſe quarrée, tout compris.</s> <s xml:id="echoid-s13563" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13564" xml:space="preserve">Les enduits des chambres & </s> <s xml:id="echoid-s13565" xml:space="preserve">autres ſeront executés avec les mê-<lb/>mes mortiers & </s> <s xml:id="echoid-s13566" xml:space="preserve">de même façon que les précédens, ayant attention <lb/>de bien moüiller les paremens pour la premiere couche.</s> <s xml:id="echoid-s13567" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13568" xml:space="preserve">Ils ſeront auſſi payés à la toiſe quarrée.</s> <s xml:id="echoid-s13569" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div690" type="section" level="1" n="187"> <head xml:id="echoid-head407" xml:space="preserve">IX.</head> <p> <s xml:id="echoid-s13570" xml:space="preserve">Les carreaux de terre, que l’on employera dans les chambres, ſe-<lb/>ront bons, bien cuits, & </s> <s xml:id="echoid-s13571" xml:space="preserve">de même échantillon, de cinq à ſix pou-<lb/>ces en quarré; </s> <s xml:id="echoid-s13572" xml:space="preserve">ils ſeront poſés ſur une forme de' terre graſſe d’en-<lb/>viron un demi pouce d’épaiſſeur, en ligne droite, & </s> <s xml:id="echoid-s13573" xml:space="preserve">en liaiſon, ſur <lb/>une couche de mortier égal à celui des maçonneries, bien de ni-<lb/>veau, pour être auſſi meſurés & </s> <s xml:id="echoid-s13574" xml:space="preserve">payés à la toiſe quarrée.</s> <s xml:id="echoid-s13575" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div691" type="section" level="1" n="188"> <head xml:id="echoid-head408" xml:space="preserve">X.</head> <p> <s xml:id="echoid-s13576" xml:space="preserve">La couverture d’ardoiſe d’Angleterre ſera bonne, noire, luiſante, <lb/>& </s> <s xml:id="echoid-s13577" xml:space="preserve">ferme, recoupée ſur trois côtez, bien appareillée, pour être po-<lb/>ſée au tiers de pureau, ou de ſa hauteur, d’alignement, à joints re-<lb/>couverts, clouée de trois bons clous chacune, ſur un plancher de <lb/>bois blanc d’un pouce d’épaiſſeur, & </s> <s xml:id="echoid-s13578" xml:space="preserve">des qualités dites à l’article 5. <lb/></s> <s xml:id="echoid-s13579" xml:space="preserve">& </s> <s xml:id="echoid-s13580" xml:space="preserve">6. </s> <s xml:id="echoid-s13581" xml:space="preserve">leſquelles planches auront été bien alignées pour être ajuſtées <lb/>& </s> <s xml:id="echoid-s13582" xml:space="preserve">jointes enſemble ſans intervale, attachées avec trois bons clous <lb/>ſur chaque chevron.</s> <s xml:id="echoid-s13583" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13584" xml:space="preserve">L’Entrepreneur en ſera payé à la toiſe quarrée, plancher & </s> <s xml:id="echoid-s13585" xml:space="preserve">tou-<lb/>tes autres fournitures compriſes, meſurées tant plein que vuide pour <lb/>les fenêtres & </s> <s xml:id="echoid-s13586" xml:space="preserve">autres ouvertures des toits, dont il ne pourra préten-<lb/>dre d’augmentation non plus que pour les bordures.</s> <s xml:id="echoid-s13587" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div692" type="section" level="1" n="189"> <head xml:id="echoid-head409" xml:space="preserve">XI.</head> <p> <s xml:id="echoid-s13588" xml:space="preserve">La plomberie au comble de ces Cazernes aura ſur l’enfaîtement <pb o="62" file="0612" n="664" rhead="LA SCIENCE DES INGENIEURS,"/> une ligne un quart d’épaiſſeur ſur dix-huit pouces de largeur, qui <lb/>feront neuf pouces de chaque côté, arrêtée avec des crochets de <lb/>fer de quatre à la toiſe, ou de pied & </s> <s xml:id="echoid-s13589" xml:space="preserve">demi en pied & </s> <s xml:id="echoid-s13590" xml:space="preserve">demi de diſ-<lb/>tance; </s> <s xml:id="echoid-s13591" xml:space="preserve">il en ſera de même des enfaîtemens des fenêtres des gale-<lb/>tas, & </s> <s xml:id="echoid-s13592" xml:space="preserve">de celui qui doit en couvrir ou en revêtir le deſſus de la <lb/>maçonnerie.</s> <s xml:id="echoid-s13593" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13594" xml:space="preserve">Le plomb des enfaîtemens des lucarnes aura quinze pouces de <lb/>large ſur une ligne d’épaiſſeur.</s> <s xml:id="echoid-s13595" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13596" xml:space="preserve">Celui des noquets pour les nouës, & </s> <s xml:id="echoid-s13597" xml:space="preserve">le long des ſouches des che-<lb/>minées, de même épaiſſeur ſur neuf pouces de large.</s> <s xml:id="echoid-s13598" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13599" xml:space="preserve">Le plomb pour revêtir les cordons, ou la panne de briſis, aura auſſi <lb/>une ligne d’épaiſſeur ſur douze pouces de large, afin de recouvrir <lb/>quatre pouces au moins partie du premier rang d’ardoiſe au deſſous <lb/>de la briſure.</s> <s xml:id="echoid-s13600" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13601" xml:space="preserve">Le plomb des arêtiers aura auſſi une ligne d’épaiſſeur ſur douze <lb/>pouces de large.</s> <s xml:id="echoid-s13602" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13603" xml:space="preserve">Celui, qui couvrira le pan coupé du côté de la cour, aura pareil-<lb/>lement douze pouces de large ſur une ligne au moins d’épaiſſeur.</s> <s xml:id="echoid-s13604" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13605" xml:space="preserve">Le plomb des chaîneaux, pour recevoir les eaux ſous l’entable-<lb/>ment, aura dix-huit pouces de large ſur une ligne & </s> <s xml:id="echoid-s13606" xml:space="preserve">demie d’épaiſ-<lb/>ſeur, arondis & </s> <s xml:id="echoid-s13607" xml:space="preserve">couverts vis-à-vis les fenêtres des galetas, pour em-<lb/>pêcher les ordures que les ſoldats y pourroient jetter; </s> <s xml:id="echoid-s13608" xml:space="preserve">ils auront un <lb/>pouce de pente par toiſe, ſoutenus par des crochets de fer de pied <lb/>& </s> <s xml:id="echoid-s13609" xml:space="preserve">demi en pied & </s> <s xml:id="echoid-s13610" xml:space="preserve">demi, afin de les conduire ſous l’aplomb des ci-<lb/>ternaux.</s> <s xml:id="echoid-s13611" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13612" xml:space="preserve">Le plomb des bavettes ou larmieres, par deſſus ces chaîneaux & </s> <s xml:id="echoid-s13613" xml:space="preserve"><lb/>l’entablement, aura trois quarts de ligne d’épaiſſeur.</s> <s xml:id="echoid-s13614" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13615" xml:space="preserve">Le plomb des deſcentes dans les citernaux & </s> <s xml:id="echoid-s13616" xml:space="preserve">pour les pompes, <lb/>de trois pouces de diametre ſur deux lignes d’épaiſſeur, ſera atta-<lb/>ché à la muraille avec des colliers de fer qui puiſſent s’ouvrir au <lb/>beſoin.</s> <s xml:id="echoid-s13617" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13618" xml:space="preserve">Tout lequel plomb ſera du meilleur que l’on puiſſe trouver, loyal <lb/>& </s> <s xml:id="echoid-s13619" xml:space="preserve">marchand, coulé en tables bien unies, ſoudé avec étain fin à l’or-<lb/>dinaire; </s> <s xml:id="echoid-s13620" xml:space="preserve">il ſera peſé au poids de la Ville, & </s> <s xml:id="echoid-s13621" xml:space="preserve">payé au quintal, ſou-<lb/>dure compriſe.</s> <s xml:id="echoid-s13622" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div693" type="section" level="1" n="190"> <head xml:id="echoid-head410" xml:space="preserve">XII.</head> <p> <s xml:id="echoid-s13623" xml:space="preserve">La ferrure dont on diſtinguera de deux ſortes.</s> <s xml:id="echoid-s13624" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13625" xml:space="preserve">Le gros fer neuf comprend tout ce qui ſera employé en gros ou-<lb/>vrages, comme les anneaux en dehors qui ſeront mis dans les murs <lb/>de face en bâtiſſant pour le beſoin des Cavaliers, les cinq chaînes <pb o="63" file="0613" n="665" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> qui traverſeront en long d’un bout à l’autre dans les dix écuries à <lb/>hauteur de la naiſſance des voûtes, ſçavoir, ſur les deux murs de <lb/>face, ſur le mur d’entrefends, & </s> <s xml:id="echoid-s13626" xml:space="preserve">le milieu des écuries, celles en <lb/>large ſur les cinq murs de refends au même quartier, & </s> <s xml:id="echoid-s13627" xml:space="preserve">ceux des <lb/>deux bouts; </s> <s xml:id="echoid-s13628" xml:space="preserve">leſquelles chaînes auront un pouce & </s> <s xml:id="echoid-s13629" xml:space="preserve">demi en quarré, <lb/>ancrées à demie brique des paremens des murs, avec des clefs de <lb/>même groſſeur de quatre à cinq pieds de longueur, bandêes au <lb/>moyen des talons ou crochets faits exprès aux forges, forts & </s> <s xml:id="echoid-s13630" xml:space="preserve">bien <lb/>ſoudés à chacune de ces chaînes, compaſſés pour être au milieu de <lb/>chaque mur, & </s> <s xml:id="echoid-s13631" xml:space="preserve">d’un coin long d’un pied avec quelques autres pe-<lb/>tits frappés à chaque endroit entre deux de ces talons ou crochets à <lb/>force avec un gros marteau, ayant attention de ne faire cette der-<lb/>niere operation, que quand les maçonneries du deſſus qui les en-<lb/>fermeront auront été élevées de cinq à ſix pieds, même davanta-<lb/>ge, pour les mieux contcnir, & </s> <s xml:id="echoid-s13632" xml:space="preserve">de laiſſer à chaque jonction de ces <lb/>talons un intervale ſuffiſant pour frapper ces grands coins & </s> <s xml:id="echoid-s13633" xml:space="preserve">petits <lb/>déja placés, juſqu’à ce que l’on voye la chaîne ſuffiſamment ten-<lb/>duë, car il ſeroit dangereux de paſſer outre.</s> <s xml:id="echoid-s13634" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13635" xml:space="preserve">Les autres ancres, molles, bandes, ou plattes formes à chaque éta-<lb/>ge, en bois de chêne dont on a parlé à l’article 5. </s> <s xml:id="echoid-s13636" xml:space="preserve">gonds, crochets, <lb/>pentures des grandes portes, éguilles des Fleurs de lys, & </s> <s xml:id="echoid-s13637" xml:space="preserve">le reſte, <lb/>lequel ſera de bonne qualité, doux, pliant, ſans paille, d’un grain <lb/>fin, clair, & </s> <s xml:id="echoid-s13638" xml:space="preserve">preſſé, non caſſant, & </s> <s xml:id="echoid-s13639" xml:space="preserve">bien forgé ſuivant les inſtruc-<lb/>tions qui ſeront données, proprement travaillé & </s> <s xml:id="echoid-s13640" xml:space="preserve">mis en œuvre.</s> <s xml:id="echoid-s13641" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13642" xml:space="preserve">Le fer à la lime & </s> <s xml:id="echoid-s13643" xml:space="preserve">d’un grain plus fin & </s> <s xml:id="echoid-s13644" xml:space="preserve">plus preſſé, ſujet à être <lb/>limé, devra être travaillé & </s> <s xml:id="echoid-s13645" xml:space="preserve">des qualités dites ci-deſſus; </s> <s xml:id="echoid-s13646" xml:space="preserve">il conſiſte-<lb/>ra en petits boulons, verroüils à reſſorts, gâches, targettes, cro-<lb/>chets, & </s> <s xml:id="echoid-s13647" xml:space="preserve">équerres des combles, la ferrure des trente-deux portes <lb/>des chambres d’Officiers, compoſée chacune de deux pentures, <lb/>une ſerrure à tour & </s> <s xml:id="echoid-s13648" xml:space="preserve">demi avec la clef, garnies differemment les <lb/>unes des autres, un gliſſoir & </s> <s xml:id="echoid-s13649" xml:space="preserve">un bouton accompagné de ſa roſette <lb/>pour les ouvrir & </s> <s xml:id="echoid-s13650" xml:space="preserve">fermer; </s> <s xml:id="echoid-s13651" xml:space="preserve">les trente du quartier des ſoldats auſſi <lb/>de differentes garnitures, & </s> <s xml:id="echoid-s13652" xml:space="preserve">celles des dix portes des écuries qui <lb/>ſeront à tour ſeulement, ayant toutes chacunes deux gros verroüils <lb/>plats ou targettes en dedans.</s> <s xml:id="echoid-s13653" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13654" xml:space="preserve">Les portes des veſtibules auront mêmes garnitures, mais plus <lb/>fortes, afin de mieux réſiſter, ſans oublier un crochet à chaque <lb/>venteau, afin de les tenir ouverts.</s> <s xml:id="echoid-s13655" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13656" xml:space="preserve">La ferrure des croiſées au quartier des Officiers conſiſtera en ſix <lb/>pentures à charnieres, deux verroüils plats, l’un en haut plus long <lb/>que l’autre en bas, ſix pattes & </s> <s xml:id="echoid-s13657" xml:space="preserve">un bouton; </s> <s xml:id="echoid-s13658" xml:space="preserve">celle des fenêtres du <pb o="64" file="0614" n="666" rhead="LA SCIENCE DES INGENIEURS,"/> quartier des ſoldats, & </s> <s xml:id="echoid-s13659" xml:space="preserve">des écuries, ſera de même qualité; </s> <s xml:id="echoid-s13660" xml:space="preserve">deſ-<lb/>quelles ferrures des portes & </s> <s xml:id="echoid-s13661" xml:space="preserve">fenêtres il ſera fait un modéle, qui, <lb/>après avoir été bien examiné & </s> <s xml:id="echoid-s13662" xml:space="preserve">approuvé, ſervira pour l’adjudica-<lb/>tion à la piece de chacune de ces ferrures, que l’Entrepreneur <lb/>ſera obligé de mettre en place où on lui indiquera; </s> <s xml:id="echoid-s13663" xml:space="preserve">fournira les <lb/>clous neceſſaires à cette fin, qui, pour les autres ouvrages, ſeront <lb/>peſez avec le reſte.</s> <s xml:id="echoid-s13664" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13665" xml:space="preserve">Ces deux ſortes de fers ſeront peſez au poids de la Ville, & </s> <s xml:id="echoid-s13666" xml:space="preserve"><lb/>payez au quintal, compris toute main d’œuvre, mais à prix <lb/>differens, la ferrure entiere des portes à la piece, ainſi que celle <lb/>des croiſées, tout compris.</s> <s xml:id="echoid-s13667" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div694" type="section" level="1" n="191"> <head xml:id="echoid-head411" xml:space="preserve">XIII.</head> <p> <s xml:id="echoid-s13668" xml:space="preserve">La vitrerie pour les croiſées ſera de verre de France bien blanc <lb/>& </s> <s xml:id="echoid-s13669" xml:space="preserve">uni, ſans pailles ni boudines, mis en plomb tiré d’un tiers de <lb/>pouce de largeur pour l’encaſtrement des carreaux, & </s> <s xml:id="echoid-s13670" xml:space="preserve">la facilité <lb/>de les remplacer lorſqu’ils ſont caſſez, proprement travaillez, <lb/>ſuivant les deſſeins qu’on donnera.</s> <s xml:id="echoid-s13671" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13672" xml:space="preserve">Il ſera meſuré au pied quarré de douze pouces, les verges de <lb/>fer compriſes, que l’Entrepreneur fournira à chaque rang de <lb/>carreaux, en groſſeur ſuffiſante pour bien affermir chaque pan-<lb/>neau, & </s> <s xml:id="echoid-s13673" xml:space="preserve">les ſoutenir contre les plus grands efforts du vent.</s> <s xml:id="echoid-s13674" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div695" type="section" level="1" n="192"> <head xml:id="echoid-head412" xml:space="preserve">XIV.</head> <p> <s xml:id="echoid-s13675" xml:space="preserve">La peinture d’impreſſion à l’huile pour les portes d’entrée, celle <lb/>des écuries, les croiſées en dehors, la panne de briſis, les lucar-<lb/>nes de bois, & </s> <s xml:id="echoid-s13676" xml:space="preserve">le reſte, ſera miſe en couleur de bois, imprimée <lb/>de deux couches compoſées de blanc de eeruſe, mêlée d’ocre <lb/>jaune, ou de telle autre couleur que l’on jugera convenir, de la <lb/>meilleure, & </s> <s xml:id="echoid-s13677" xml:space="preserve">broyée avec de l’huile de lin, dont la ſeconde cou-<lb/>che ne ſe mettra que lorſque la premiere ſera bien ſeche.</s> <s xml:id="echoid-s13678" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13679" xml:space="preserve">Cet ouvrage ſera meſuré, réduit, & </s> <s xml:id="echoid-s13680" xml:space="preserve">payé à la toiſe quarrée.</s> <s xml:id="echoid-s13681" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div696" type="section" level="1" n="193"> <head xml:id="echoid-head413" xml:space="preserve">XV.</head> <p> <s xml:id="echoid-s13682" xml:space="preserve">Les trois Fleurs de lys à quatre angles pour les deux coupes, & </s> <s xml:id="echoid-s13683" xml:space="preserve"><lb/>le milieu de l’équerre de ces cazernes, ſeront de cuivre jaune, <lb/>de quatre pieds & </s> <s xml:id="echoid-s13684" xml:space="preserve">demi de hauteur, non compris le globe qui en <lb/>fera la baſe; </s> <s xml:id="echoid-s13685" xml:space="preserve">on les executera ſuivant le deſſein, & </s> <s xml:id="echoid-s13686" xml:space="preserve">conformement <lb/>au modele en carton, qui en a été dreſſé, bien ſoudées, & </s> <s xml:id="echoid-s13687" xml:space="preserve">en <pb o="65" file="0615" n="667" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> outre cloüées de clous auſſi de cuivre, rivés de diſtance à autre, <lb/>pour enſuite être dorées, & </s> <s xml:id="echoid-s13688" xml:space="preserve">poſées dans une éguille de fer qui les <lb/>traverſera d’un bout à l’autre, ſans bleſſer le métal, compaſſant <lb/>ſa groſſeur au vuide du collet de ces Fleurs de lys, dont le pied ſe-<lb/>ra cloüé ſur le bois du comble, & </s> <s xml:id="echoid-s13689" xml:space="preserve">recouvert par le plomb des en-<lb/>faîtemens.</s> <s xml:id="echoid-s13690" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div697" type="section" level="1" n="194"> <head xml:id="echoid-head414" xml:space="preserve">XVI.</head> <head xml:id="echoid-head415" xml:space="preserve"><emph style="sc">Conditions generales</emph>.</head> <p> <s xml:id="echoid-s13691" xml:space="preserve">Les Entrepreneurs ſe conformeront aux termes du preſent De-<lb/>vis, & </s> <s xml:id="echoid-s13692" xml:space="preserve">ne pourront commencer aucun travail de quelque nature <lb/>qu’il puiſſe être, qu’auparavant il n’ait été tracé, alligné, & </s> <s xml:id="echoid-s13693" xml:space="preserve">ordonné <lb/>par M. </s> <s xml:id="echoid-s13694" xml:space="preserve">le Comte de Vauban, Directeur des Fortifications de cette <lb/>Province, ou en ſon abſence par l’Ingenieur en chef de la Place; <lb/></s> <s xml:id="echoid-s13695" xml:space="preserve">& </s> <s xml:id="echoid-s13696" xml:space="preserve">au cas qu’il ſe trouve pendant le cours & </s> <s xml:id="echoid-s13697" xml:space="preserve">après l’achevement <lb/>du travail quelques mal-façons de leur part, ils ſeront tenus de <lb/>le refaire à leurs frais, ſans pouvoir prétendre d’être dedommagez: </s> <s xml:id="echoid-s13698" xml:space="preserve"><lb/>tous leſquels ouvrages ne leur ſeront comptez qu’une fois ſeule-<lb/>ment, & </s> <s xml:id="echoid-s13699" xml:space="preserve">payés au prix de l’adjudication qui en aura été faite cha-<lb/>que année.</s> <s xml:id="echoid-s13700" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13701" xml:space="preserve">Les Entrepreneurs ſe fourniront ſans exception detous les mate-<lb/>riaux, outils, échaffauts, ceintres des voûtes, & </s> <s xml:id="echoid-s13702" xml:space="preserve">autres choſes ne-<lb/>ceſſaires pour l’entier & </s> <s xml:id="echoid-s13703" xml:space="preserve">parfaite execution de leur entrepriſe, <lb/>employant le nombre d’hommes ſuffiſant, & </s> <s xml:id="echoid-s13704" xml:space="preserve">qui leur ſera ordon-<lb/>né pour diligenter le travail, afin qu’il ſoit fait en bonne ſaiſon; <lb/></s> <s xml:id="echoid-s13705" xml:space="preserve">& </s> <s xml:id="echoid-s13706" xml:space="preserve">au cas de retardement, il en ſera mis à leurs frais, autant qu’il <lb/>ſera jugé neceſſaire: </s> <s xml:id="echoid-s13707" xml:space="preserve">ſuivront en tout les ordres qu’ils recevront, <lb/>& </s> <s xml:id="echoid-s13708" xml:space="preserve">les deſſeins qui leur ſeront donnez, n’employant que des mate-<lb/>riaux conditionnez comme il eſt dit, qui ſeront ſujets à verifica-<lb/>tion & </s> <s xml:id="echoid-s13709" xml:space="preserve">reception, rejettant tous ceux qui ne ſe trouveront pas des <lb/>qualités & </s> <s xml:id="echoid-s13710" xml:space="preserve">dimenſions requiſes au preſent Devis, & </s> <s xml:id="echoid-s13711" xml:space="preserve">ne pourront <lb/>prétendre leur entier & </s> <s xml:id="echoid-s13712" xml:space="preserve">parfait payement qu’après l’achevement <lb/>& </s> <s xml:id="echoid-s13713" xml:space="preserve">reception d’iceux, qu’ils garantiront pendant un an, à compter <lb/>du jour qu’ils auront été reçûs, & </s> <s xml:id="echoid-s13714" xml:space="preserve">pour ſureté de l’execution d’i-<lb/>ceux & </s> <s xml:id="echoid-s13715" xml:space="preserve">des deniers du Roy, qu’ils recevront à compte à fur & </s> <s xml:id="echoid-s13716" xml:space="preserve">à <lb/>meſure que le travail avancera; </s> <s xml:id="echoid-s13717" xml:space="preserve">ils donneront bonne & </s> <s xml:id="echoid-s13718" xml:space="preserve">ſuffiſante <lb/>caution.</s> <s xml:id="echoid-s13719" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13720" xml:space="preserve">S’il ſurvient quelque ouvrage extraordinaire & </s> <s xml:id="echoid-s13721" xml:space="preserve">imprévû pen-<lb/>dant le cours de l’année; </s> <s xml:id="echoid-s13722" xml:space="preserve">les Entrepreneurs ſeront obligez de le <lb/>faire par continuation du prix de chaque nature dont ils ſeront <pb o="66" file="0616" n="668" rhead="LA SCIENCE DES INGENIEURS,"/> convenus; </s> <s xml:id="echoid-s13723" xml:space="preserve">& </s> <s xml:id="echoid-s13724" xml:space="preserve">ſi reciproquement on trouvoit à propos de changer, <lb/>retrancher, ou differer à une autre année quelqu’un de ceux qui <lb/>ſont ordonnez, les Entrepreneurs ne pourront en prétendre au-<lb/>cun dédommagement.</s> <s xml:id="echoid-s13725" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13726" xml:space="preserve">Ils feront tranſporter toutes les décombres provenantes des con-<lb/>ſtructions ou démolitions de leur ouvrages, aux lieux qui leur <lb/>ſeront indiquez; </s> <s xml:id="echoid-s13727" xml:space="preserve">& </s> <s xml:id="echoid-s13728" xml:space="preserve">ſi quelqu’un manque d’avoir achevé ſon en-<lb/>trepriſe par negligence, à la fin du mois de Septembre prochain, <lb/>il ſera condamné à une amende proportionnée au travail dont il <lb/>aura été chargé.</s> <s xml:id="echoid-s13729" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13730" xml:space="preserve">Bien entendu qu’encore que le preſent Devis comprenne ce qui <lb/>doit entrer dans la conſtruction totale de ces Cazernes, il ne <lb/>pourra cependant ſervir à cette fin, que pour la conſommation <lb/>des fonds qui ſeront ordonnez chaque année.</s> <s xml:id="echoid-s13731" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13732" xml:space="preserve">Chaque Entrepreneur ſera tenu au dédommagement desproprie-<lb/>taires ſur les heritages deſquels il prendra ou voiturera les mate-<lb/>riaux de gré à gré, ou ſuivant l’eſtimation qui en ſera faite par <lb/>deux Experts nommez de part & </s> <s xml:id="echoid-s13733" xml:space="preserve">d’autre; </s> <s xml:id="echoid-s13734" xml:space="preserve">& </s> <s xml:id="echoid-s13735" xml:space="preserve">ſi il arrive quelques <lb/>difficultez entre les Entrepreneurs, ou entr’eux & </s> <s xml:id="echoid-s13736" xml:space="preserve">leurs cautions, <lb/>comptes & </s> <s xml:id="echoid-s13737" xml:space="preserve">décomptes, qui ayent rapport directement ou indirec-<lb/>tement à l’execution de leurs ouvrages, & </s> <s xml:id="echoid-s13738" xml:space="preserve">que tout ne ſoit pas aſ-<lb/>ſez clairement expliqué par le preſent Devis, ils ſe conformeront <lb/>ſans appel à ce qui ſera reglé par le Directeur des Fortifications, <lb/>ou en ſon abſence par l’Ingenieur en chef; </s> <s xml:id="echoid-s13739" xml:space="preserve">& </s> <s xml:id="echoid-s13740" xml:space="preserve">ils ne pourront, ſans <lb/>leur conſentement, rendre leurs ouvrages par ſous-entrepriſes, <lb/>ni s’aſſocier.</s> <s xml:id="echoid-s13741" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s13742" xml:space="preserve">Fait à Bethune, le vingt-deux Mars mil ſept cent vingt-deux,</s> </p> <p> <s xml:id="echoid-s13743" xml:space="preserve">D’ARTEZAY, Ingenieur en Chef.</s> <s xml:id="echoid-s13744" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13745" xml:space="preserve">Quand on fera des Devis, il eſt à propos de lier les Entrepreneurs, <lb/>autant qu’il eſt poſſible, ainſi qu’on vient de le voir dans les con-<lb/>ditions précédentes, afin de prévenir toutes les conteſtations, & </s> <s xml:id="echoid-s13746" xml:space="preserve"><lb/>les relâchemens auſquels la plûpart ſon aſſez ſujets.</s> <s xml:id="echoid-s13747" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s13748" xml:space="preserve">Voici un Devis qui pourra ſervir de Formulaire pour les Magazins <lb/>à Poudre; </s> <s xml:id="echoid-s13749" xml:space="preserve">il vient de M. </s> <s xml:id="echoid-s13750" xml:space="preserve">de Muz, Directeur des Fortifications, <lb/>qui a bien voulu prendre la peine de le compoſer exprès pour me faire <lb/>plaiſir.</s> <s xml:id="echoid-s13751" xml:space="preserve"/> </p> <pb o="67" file="0617" n="669" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s13752" xml:space="preserve">DEVIS POUR LA CONSTRUCTION D’UN <lb/>Magazin à Poudre, très-ſolide, de dix toiſes de lon-<lb/>gueur ſur quatre de large.</s> <s xml:id="echoid-s13753" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div698" type="section" level="1" n="195"> <head xml:id="echoid-head416" xml:space="preserve"><emph style="sc">Premierement</emph>.</head> <p> <s xml:id="echoid-s13754" xml:space="preserve">P Lacer autant que faire ſe pourra le Magazin dans un lieu le <lb/>plus ſec, le plus à couvert, & </s> <s xml:id="echoid-s13755" xml:space="preserve">le moins expoſé au front des <lb/>attaques, non plus que ſes portes & </s> <s xml:id="echoid-s13756" xml:space="preserve">fenêtres au vent d’Oüeſt.</s> <s xml:id="echoid-s13757" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div699" type="section" level="1" n="196"> <head xml:id="echoid-head417" xml:space="preserve">II.</head> <p> <s xml:id="echoid-s13758" xml:space="preserve">Après que l’Ingenieur en Chef aura diſtribué le Plan, Profil, & </s> <s xml:id="echoid-s13759" xml:space="preserve"><lb/>le Devis aux Entrepreneurs, & </s> <s xml:id="echoid-s13760" xml:space="preserve">tracé tout l’interieur des murs, on <lb/>marquera la largeur de la foüille des terres pour la fondation juſ-<lb/>ques au bon, vif, & </s> <s xml:id="echoid-s13761" xml:space="preserve">ſolide fond, que nous ſuppoſons ici de ſix <lb/>pieds de profondeur ſeulement, & </s> <s xml:id="echoid-s13762" xml:space="preserve">plus ou moins bas s’il en eſt <lb/>neceſſaire; </s> <s xml:id="echoid-s13763" xml:space="preserve">ſur la largeur de huit pieds dans le fond pour les longs <lb/>côtez, bien mis de niveau, & </s> <s xml:id="echoid-s13764" xml:space="preserve">les terres coupées à plomb, & </s> <s xml:id="echoid-s13765" xml:space="preserve">étre-<lb/>ſillonnées pour qu’il ne s’y faſſe point d’éboulement.</s> <s xml:id="echoid-s13766" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div700" type="section" level="1" n="197"> <head xml:id="echoid-head418" xml:space="preserve">III.</head> <p> <s xml:id="echoid-s13767" xml:space="preserve">Enſuite on poſera de gros moilons ou libages, avec de bons lits, <lb/>& </s> <s xml:id="echoid-s13768" xml:space="preserve">joints à ſec, & </s> <s xml:id="echoid-s13769" xml:space="preserve">on maçonnera au deſſus avec pareille matiere <lb/>en bon mortier, juſques à deux pieds trois pouces de hauteur, bien <lb/>araſée de pied en pied; </s> <s xml:id="echoid-s13770" xml:space="preserve">après quoi on poſera au deſſus une chaîne <lb/>de deux aſſiſes de briques, traverſant toute la largeur du mur, <lb/>dont la ſeconde ſera en boutiſſe par les deux extremités, & </s> <s xml:id="echoid-s13771" xml:space="preserve">ſur <lb/>laquelle on fera retraite de trois pouces de part & </s> <s xml:id="echoid-s13772" xml:space="preserve">d’autre: </s> <s xml:id="echoid-s13773" xml:space="preserve">on <lb/>recommencera à élever encore deux pieds trois pouces en moi-<lb/>lon, faiſant parement bien dreſſé & </s> <s xml:id="echoid-s13774" xml:space="preserve">à plomb tant ſur le devant <lb/>que ſur le derriere, en ſorte que l’achevement de toute la hau-<lb/>teur deſdits ſix pieds, ainſi que de toutes les fondations, ſoit qu’el-<lb/>les ayent plus ou moins de profondeur, ſoient terminées par cinq <lb/>aſſiſes de briques, dont la derniere ſera auſſi en boutiſſe, pour <lb/>avoir neuf pouces de retraite ſur le devant, trois ſur le derriere, <lb/>& </s> <s xml:id="echoid-s13775" xml:space="preserve">réduire les murs des longs côtez à ſept pieds d’épaiſſeur.</s> <s xml:id="echoid-s13776" xml:space="preserve"/> </p> <pb o="68" file="0618" n="670" rhead="LA SCIENCE DES INGENIEURS,"/> </div> <div xml:id="echoid-div701" type="section" level="1" n="198"> <head xml:id="echoid-head419" xml:space="preserve">IV.</head> <p> <s xml:id="echoid-s13777" xml:space="preserve">On fondera auſſi en même tems, & </s> <s xml:id="echoid-s13778" xml:space="preserve">auſſi bas, les piliers buttans, <lb/>& </s> <s xml:id="echoid-s13779" xml:space="preserve">les murs de face ſous les deux pignons, en y obſervant toutes <lb/>les bonnes façons, liaiſons, & </s> <s xml:id="echoid-s13780" xml:space="preserve">ſimetries que ci-devant; </s> <s xml:id="echoid-s13781" xml:space="preserve">le tout poſé <lb/>en bon mortier ordinaire, compoſé d’un tiers de bonne chaux <lb/>éteinte toute vive, & </s> <s xml:id="echoid-s13782" xml:space="preserve">deux tiers du meilleur ſable bien battu, <lb/>démêlé & </s> <s xml:id="echoid-s13783" xml:space="preserve">corroyé, en ſorte qu’il ne faſſe plus qu’un même corps, <lb/>& </s> <s xml:id="echoid-s13784" xml:space="preserve">mis en œuvre ſeulement vingt-quatre heures après, & </s> <s xml:id="echoid-s13785" xml:space="preserve">le ra-<lb/>bottant & </s> <s xml:id="echoid-s13786" xml:space="preserve">corroyant tout de nouveau, ſans y mettre de l’eau que <lb/>la premiere fois.</s> <s xml:id="echoid-s13787" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div702" type="section" level="1" n="199"> <head xml:id="echoid-head420" xml:space="preserve">V.</head> <p> <s xml:id="echoid-s13788" xml:space="preserve">Leſdits piliers buttans auront chacun quatre pieds ſix pouces <lb/>de large, ſur ſix pieds ſix pouces de queuë en fondation, réduit <lb/>enſuite à cinq pieds ſix pouces, & </s> <s xml:id="echoid-s13789" xml:space="preserve">quatre pieds au nœud de leurs <lb/>paremens, pour avoir deux retraites de trois pouces chacune.</s> <s xml:id="echoid-s13790" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div703" type="section" level="1" n="200"> <head xml:id="echoid-head421" xml:space="preserve">VI.</head> <p> <s xml:id="echoid-s13791" xml:space="preserve">Les fondations des deux pignons auront chacune cinq pieds de <lb/>large, & </s> <s xml:id="echoid-s13792" xml:space="preserve">le mur réduit à quatre pieds, à cauſe des retraites du <lb/>devant & </s> <s xml:id="echoid-s13793" xml:space="preserve">du derriere; </s> <s xml:id="echoid-s13794" xml:space="preserve">le tout conſtruit en même temps pour faire <lb/>meilleure liaiſon.</s> <s xml:id="echoid-s13795" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div704" type="section" level="1" n="201"> <head xml:id="echoid-head422" xml:space="preserve">VII.</head> <p> <s xml:id="echoid-s13796" xml:space="preserve">Si le fond du terrain ſe trouvoit tendre, foible, ou douteux, <lb/>après l’avoir ſondé avec la ſonde à tarriere, on le fortifiera par <lb/>une grille de charpente de bois de chêne, compoſée de lon-<lb/>grines & </s> <s xml:id="echoid-s13797" xml:space="preserve">racinaux de dix pouces quarrés aſſemblée par entailles <lb/>à queuë d’aronde aux extremtiés par le devant & </s> <s xml:id="echoid-s13798" xml:space="preserve">le derriere, & </s> <s xml:id="echoid-s13799" xml:space="preserve"><lb/>tenuës en raiſon avec de bonnes chevilles de fer ébarbellées, en-<lb/>foncées à tête perduë, après quoi les araſer de moilon ou libage, <lb/>comme il eſt dit ci-devant.</s> <s xml:id="echoid-s13800" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div705" type="section" level="1" n="202"> <head xml:id="echoid-head423" xml:space="preserve">VIII.</head> <p> <s xml:id="echoid-s13801" xml:space="preserve">Que s’il y avoit plus de précaution à prendre, il faudroit cou-<lb/>vrir toute la ſuperficie de ladite grille par un plancher de ma-<lb/>driers de bois de chêne de ſix pouces d’épaiſſeur, ſur huit, dix, & </s> <s xml:id="echoid-s13802" xml:space="preserve"><lb/>douze de largeur, bien joints l’un contre l’autre, les laiſſant dé-<lb/>border de deux ou trois pouces ſur le devant & </s> <s xml:id="echoid-s13803" xml:space="preserve">le derriere de la <pb o="69" file="0619" n="671" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> fondation, avec une eſpece de mentonnet, ou bien un hurtoir <lb/>pour contenir le premier moilon ou libage poſé à ſec, & </s> <s xml:id="echoid-s13804" xml:space="preserve">l’empê-<lb/>cher de gliſſer au vuide lorſqu’il ſeroit chargé.</s> <s xml:id="echoid-s13805" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div706" type="section" level="1" n="203"> <head xml:id="echoid-head424" xml:space="preserve">IX.</head> <p> <s xml:id="echoid-s13806" xml:space="preserve">Piloter même au deſſous de la grille, s’il en étoit neceſſaire, pour <lb/>plus de ſolidité & </s> <s xml:id="echoid-s13807" xml:space="preserve">de ſureté, & </s> <s xml:id="echoid-s13808" xml:space="preserve">cela fait ſelon l’uſage du pilotage <lb/>dont nous ne faiſons point le détail.</s> <s xml:id="echoid-s13809" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div707" type="section" level="1" n="204"> <head xml:id="echoid-head425" xml:space="preserve">X.</head> <p> <s xml:id="echoid-s13810" xml:space="preserve">Toutes ces fondations miſes à leur hauteur, on fera courir le <lb/>niveau tout au tour, après quoi on établira les murs au-deſſus, <lb/>ſelon les largeurs ci-devant ſpécifiées, donnant un peu de fruit <lb/>au parement exterieur, c’eſt-à-dire, deux ou trois lignes par pied, <lb/>& </s> <s xml:id="echoid-s13811" xml:space="preserve">le parement interieur bien monté à plomb; </s> <s xml:id="echoid-s13812" xml:space="preserve">enſuite on poſera <lb/>d’abord cinq aſſiſes de pierres dures, non geliſſes, ou de graiſſe-<lb/>rie, en tous les paremens exterieurs, dont les carreaux auront <lb/>dix à douze pouces de face, ſur neuf à dix de queuë à joints quar-<lb/>rez & </s> <s xml:id="echoid-s13813" xml:space="preserve">d’équerre; </s> <s xml:id="echoid-s13814" xml:space="preserve">& </s> <s xml:id="echoid-s13815" xml:space="preserve">de trois en trois carreaux on placera une <lb/>boutiſſe à tête quarrée, ſur dix-huit à vingt pouces de queuë; <lb/></s> <s xml:id="echoid-s13816" xml:space="preserve">le tout bien eſſemillé & </s> <s xml:id="echoid-s13817" xml:space="preserve">équarri; </s> <s xml:id="echoid-s13818" xml:space="preserve">obſervant que leſdites boutiſſes <lb/>ne doivent pas être miſes l’une ſur l’autre dans les aſſiſes au deſ-<lb/>ſus, mais en quinconche ou en échiquier, avec des coins à tous <lb/>les angles, & </s> <s xml:id="echoid-s13819" xml:space="preserve">aux pieds droits des portes & </s> <s xml:id="echoid-s13820" xml:space="preserve">fenêtres; </s> <s xml:id="echoid-s13821" xml:space="preserve">le tout en <lb/>bon mortier de ciment, compoſé d’un tiers de bonne chaux vive, <lb/>& </s> <s xml:id="echoid-s13822" xml:space="preserve">de deux tiers de poudre de vieux tuilots, bien pulveriſé & </s> <s xml:id="echoid-s13823" xml:space="preserve"><lb/>paſſé au tamis, battu, demêlé, & </s> <s xml:id="echoid-s13824" xml:space="preserve">corroyé, en ſorte qu’ils ne faſſent <lb/>plus qu’un même corps, fait de quinze jours avant que de le <lb/>mettre en œuvre, pendant lequel tems on le rebattra de nouveau <lb/>à pluſieurs repriſes avec la batte de fer, dans un petit baſſin ou <lb/>auget d’un pied quarré fait exprès, avec des planches par les <lb/>côtez, & </s> <s xml:id="echoid-s13825" xml:space="preserve">un gros madrier dans le fond, & </s> <s xml:id="echoid-s13826" xml:space="preserve">toûjours ſans y mettre <lb/>de l’eau que la premiere fois.</s> <s xml:id="echoid-s13827" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div708" type="section" level="1" n="205"> <head xml:id="echoid-head426" xml:space="preserve">XI.</head> <p> <s xml:id="echoid-s13828" xml:space="preserve">Et comme la plûpart des pierres, & </s> <s xml:id="echoid-s13829" xml:space="preserve">ſur-tout celles de graiſſe-<lb/>rie, ſont fort ſuſceptibles d’impreſſion de la gelée, à cauſe de la <lb/>nature de leurs pores; </s> <s xml:id="echoid-s13830" xml:space="preserve">il faut que le derriere deſdites cinq aſſiſes, <pb o="70" file="0620" n="672" rhead="LA SCIENCE DES INGENIEURS,"/> ſoit rencontré & </s> <s xml:id="echoid-s13831" xml:space="preserve">maçonné au moins avec deux briques en bou-<lb/>tiſſes, poſées en mortier ordinaire.</s> <s xml:id="echoid-s13832" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div709" type="section" level="1" n="206"> <head xml:id="echoid-head427" xml:space="preserve">XII.</head> <p> <s xml:id="echoid-s13833" xml:space="preserve">Tous les paremens interieurs deſdits murs ſeront de bonnes bri-<lb/>ques bien cuites & </s> <s xml:id="echoid-s13834" xml:space="preserve">bien moulées, faits par plombées de cinq aſ-<lb/>ſiſes, faiſant enſemble un pied de hauteur, y compris le mortier, <lb/>dont la premiere aura trois briques & </s> <s xml:id="echoid-s13835" xml:space="preserve">demie, la ſeconde trois bri-<lb/>ques, la troiſiéme deux briques & </s> <s xml:id="echoid-s13836" xml:space="preserve">demi, la quatriéme deux bri-<lb/>ques, & </s> <s xml:id="echoid-s13837" xml:space="preserve">la cinquiéme une & </s> <s xml:id="echoid-s13838" xml:space="preserve">demie, afin d’obſerver une bonne <lb/>liaiſon, & </s> <s xml:id="echoid-s13839" xml:space="preserve">l’intervalle entre leſdites briques, & </s> <s xml:id="echoid-s13840" xml:space="preserve">celles qui ont garni <lb/>le derriere de la graiſſerie ſeront maçonnées en mortier, poſées à <lb/>la main, preſſées du talon du marteau, en bon moilon ordinaire, <lb/>en ſorte qu’il ſouffle de toutes parts, & </s> <s xml:id="echoid-s13841" xml:space="preserve">araſé à chaque pied de <lb/>hauteur.</s> <s xml:id="echoid-s13842" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div710" type="section" level="1" n="207"> <head xml:id="echoid-head428" xml:space="preserve">XIII.</head> <p> <s xml:id="echoid-s13843" xml:space="preserve">Au deſſus des cinq aſſiſes de graiſſerie, on fera parement de <lb/>briques par plombées, comme ci-devant, & </s> <s xml:id="echoid-s13844" xml:space="preserve">l’entre-deux ma-<lb/>çonné en moilon, obſervant que le dehors & </s> <s xml:id="echoid-s13845" xml:space="preserve">le dedans montent <lb/>également, & </s> <s xml:id="echoid-s13846" xml:space="preserve">en même tems avec des coins de grès retournés en <lb/>liaiſon à tous les angles poſés en mortier de ciment.</s> <s xml:id="echoid-s13847" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div711" type="section" level="1" n="208"> <head xml:id="echoid-head429" xml:space="preserve">XIV.</head> <p> <s xml:id="echoid-s13848" xml:space="preserve">Les longs côtez ſeront élevez de même juſqu’à cinq ou ſix pieds <lb/>plus ou moins, ſelon le beſoin, après quoi ils ſeront terminez par <lb/>cinq aſſiſes de briques, traverſant d’un parement à l’autre pour <lb/>recevoir la naiſſance de la voûte, dont la derniere aſſiſe ſera po-<lb/>ſée par précaution en doüelle & </s> <s xml:id="echoid-s13849" xml:space="preserve">coupe de vouſſoir, ſelon le cein-<lb/>tre de la voûte, pour éviter le défaut des cales ou gros mortier <lb/>que les Maçons mettent mal à propos ſous la premiere brique <lb/>qu’ils poſent, pour racheter la retombée du ceintre; </s> <s xml:id="echoid-s13850" xml:space="preserve">le tout à <lb/>petits joints, & </s> <s xml:id="echoid-s13851" xml:space="preserve">à petits lits, ſans faire de trop gros mortier.</s> <s xml:id="echoid-s13852" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div712" type="section" level="1" n="209"> <head xml:id="echoid-head430" xml:space="preserve">XV.</head> <p> <s xml:id="echoid-s13853" xml:space="preserve">La voûte ſera faite en plein ceintre, comme la plus ſolide, de <lb/>trois pieds & </s> <s xml:id="echoid-s13854" xml:space="preserve">demi d’épaiſſeur au moins, toute de bonnes bri-<lb/>ques choiſies, bien cuites & </s> <s xml:id="echoid-s13855" xml:space="preserve">bien moulées, frottées & </s> <s xml:id="echoid-s13856" xml:space="preserve">dreſſées à <pb o="71" file="0621" n="673" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> la main l’une contre l’autre, poſées à petits joints en bon mortier, <lb/>ſans grumeaux, ni grains de ſable, tres-bien & </s> <s xml:id="echoid-s13857" xml:space="preserve">également cein-<lb/>trées dans toute ſa longueur & </s> <s xml:id="echoid-s13858" xml:space="preserve">largeur; </s> <s xml:id="echoid-s13859" xml:space="preserve">tous les materiaux choi-<lb/>ſis & </s> <s xml:id="echoid-s13860" xml:space="preserve">bien appareillés, c’eſt-à-dire, des vouſſoirs pendans & </s> <s xml:id="echoid-s13861" xml:space="preserve">cla-<lb/>vaux conditionnés, & </s> <s xml:id="echoid-s13862" xml:space="preserve">taillés exprès, ſi c’eſt de pierres.</s> <s xml:id="echoid-s13863" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13864" xml:space="preserve">Mais ſi c’eſt de briques, comme la meilleure matiere à ce ſujet, <lb/>il faudra d’abord les bâtir par une brique d’épaiſſeur, bandée, & </s> <s xml:id="echoid-s13865" xml:space="preserve"><lb/>bien ficher des coins de bois ſur la clef, & </s> <s xml:id="echoid-s13866" xml:space="preserve">bien arrondir ſon ex-<lb/>trados, pour recommencer une ſeconde voûte, repetées juſqu’à <lb/>quatre fois l’une ſur l’autre, faiſant enſemble au moins trois pieds.</s> <s xml:id="echoid-s13867" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div713" type="section" level="1" n="210"> <head xml:id="echoid-head431" xml:space="preserve">XVI.</head> <p> <s xml:id="echoid-s13868" xml:space="preserve">On élevera en même tems les pieds droits, les piliers buttans, <lb/>& </s> <s xml:id="echoid-s13869" xml:space="preserve">les murs des pignons au deſſus de la voûte, que l’on terminera <lb/>en dos d’aſne, ou cape de bâtardeau, avec des pentes de part & </s> <s xml:id="echoid-s13870" xml:space="preserve"><lb/>d’autre, dirigées comme celles des égoûts d’un toit; </s> <s xml:id="echoid-s13871" xml:space="preserve">le tout en <lb/>brique ſans moilonnage, à cauſe de la gelée. </s> <s xml:id="echoid-s13872" xml:space="preserve">Sur la ſuperficie deſ-<lb/>dites pentes, on fera une crêmaillerie, dont les intervalles ſeront <lb/>proportionnés ſelon la longueur de la tuile & </s> <s xml:id="echoid-s13873" xml:space="preserve">ſon crochet, afin d’ob-<lb/>ſerver le pureau ordinaire, pour quel effet on préferera toujours la <lb/>tuile au grand moule à celle du petit, l’une & </s> <s xml:id="echoid-s13874" xml:space="preserve">l’autre poſées en bon <lb/>mortier ordinaire, & </s> <s xml:id="echoid-s13875" xml:space="preserve">encore mieux en mortier de ciment, ou tout <lb/>au moius moitié de l’un & </s> <s xml:id="echoid-s13876" xml:space="preserve">de l’autre de ces derniers, bien mêlés <lb/>enſemble, & </s> <s xml:id="echoid-s13877" xml:space="preserve">la couverture faite en bonne ſaiſon.</s> <s xml:id="echoid-s13878" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div714" type="section" level="1" n="211"> <head xml:id="echoid-head432" xml:space="preserve">XVII.</head> <p> <s xml:id="echoid-s13879" xml:space="preserve">Si on ne veut pas mettre en uſage leſdites crémailleres, on en-<lb/>caſtrera à ſec dans la maçonnerie les pannes ſablieres ou ventrie-<lb/>res, & </s> <s xml:id="echoid-s13880" xml:space="preserve">les chevrons de bois de chêne, eſpacez de quatre à la latte, <lb/>que l’on laiſſera déborder de toute l’épaiſſeur de ladite latte, pour <lb/>recevoir le crochet de la tuile, & </s> <s xml:id="echoid-s13881" xml:space="preserve">poſée en mortier comme ci-de-<lb/>vant.</s> <s xml:id="echoid-s13882" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div715" type="section" level="1" n="212"> <head xml:id="echoid-head433" xml:space="preserve">XVIII.</head> <p> <s xml:id="echoid-s13883" xml:space="preserve">Et ſi on vouloit couvrir d’ardoiſe, au lieu de lattes voliſſes, on <lb/>mettra de bons feüillets de chêne bien ſec, cloüés avec deux clous <lb/>à chaque chevron, avec des contre-lattes de ſciage, ſur leſquelles <lb/>on poſera l’ardoiſe attachée au moins avec trois clous chacune, <lb/>obſervant toujours le pureau ordinaire; </s> <s xml:id="echoid-s13884" xml:space="preserve">& </s> <s xml:id="echoid-s13885" xml:space="preserve">en ces deux derniers <pb o="72" file="0622" n="674" rhead="LA SCIENCE DES INGENIEURS,"/> cas, il faudra abſolument mettre un entablement de pierres de <lb/>taille, ou de briques de cant, avec une platte - forme de char-<lb/>pente au-deſſus, pour recevoir & </s> <s xml:id="echoid-s13886" xml:space="preserve">retenir les pas des chevrons, au <lb/>bas deſquels on pourra mettre des coyaux; </s> <s xml:id="echoid-s13887" xml:space="preserve">mais cela eſt bien <lb/>ſujet au feu, & </s> <s xml:id="echoid-s13888" xml:space="preserve">empêche de voir les endroits par où les eaux de <lb/>pluyes peuvent tomber ſur la maçonnerie, & </s> <s xml:id="echoid-s13889" xml:space="preserve">la dégrader; </s> <s xml:id="echoid-s13890" xml:space="preserve">& </s> <s xml:id="echoid-s13891" xml:space="preserve"><lb/>quant aux couvertures de dales de pierre, non ſeulement elles <lb/>chargent trop, mais elles ſont encore ſujettes à s’éclater, & </s> <s xml:id="echoid-s13892" xml:space="preserve">fen-<lb/>dre par les neiges & </s> <s xml:id="echoid-s13893" xml:space="preserve">les grandes gelées, & </s> <s xml:id="echoid-s13894" xml:space="preserve">les mortiers s’affament, <lb/>& </s> <s xml:id="echoid-s13895" xml:space="preserve">c’eſt toujours à recommencer à les reparer.</s> <s xml:id="echoid-s13896" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div716" type="section" level="1" n="213"> <head xml:id="echoid-head434" xml:space="preserve">XIX.</head> <p> <s xml:id="echoid-s13897" xml:space="preserve">Les bayes des deux portes des pignons auront chacune quatre <lb/>pieds de large, ſur ſept & </s> <s xml:id="echoid-s13898" xml:space="preserve">demi de hauteur, voutées en plein cein-<lb/>tre, leurs pieds droits garnis de pierres de taille, avec deux bat-<lb/>tées; </s> <s xml:id="echoid-s13899" xml:space="preserve">les deux fenêtres au deſſus auront chacune trois pieds de <lb/>large, ſur cinq de hauteur, avec double battée, & </s> <s xml:id="echoid-s13900" xml:space="preserve">voûtées en <lb/>ceintre ſurbaiſſé.</s> <s xml:id="echoid-s13901" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div717" type="section" level="1" n="214"> <head xml:id="echoid-head435" xml:space="preserve">XX.</head> <p> <s xml:id="echoid-s13902" xml:space="preserve">Les doubles fermetures des bayes deſdites portes ſeront faites <lb/>à deux ventaux avec des planches de bon bois de chêne bien ſec, <lb/>de deux pouces d’épaiſſeur, bien jointes à feüilleures l’une contre <lb/>l’autre, garnies par leurs derrieres de bonnes barres de pareil bois, <lb/>& </s> <s xml:id="echoid-s13903" xml:space="preserve">bien cloüées avec des clous picarts, rivés par le dedans: </s> <s xml:id="echoid-s13904" xml:space="preserve">les <lb/>volets des fenêtres ſeront ſimples, mais avec des bois & </s> <s xml:id="echoid-s13905" xml:space="preserve">planches <lb/>des mêmes qualités, & </s> <s xml:id="echoid-s13906" xml:space="preserve">les unes & </s> <s xml:id="echoid-s13907" xml:space="preserve">les autres recouvertes avec des <lb/>lames de tôle de Hollande, cloüées ſur les planches, & </s> <s xml:id="echoid-s13908" xml:space="preserve">rivés auſſi <lb/>par le derriere, garnis de leurs gonds, pentures, pivots, ou pio-<lb/>ches, avec des crapaudines ſellées en plomb dans des dez de grés; <lb/></s> <s xml:id="echoid-s13909" xml:space="preserve">de bonnes ſerrures à boſſes à doubles tours, toutes differentes, <lb/>avec de bons & </s> <s xml:id="echoid-s13910" xml:space="preserve">forts verroüils.</s> <s xml:id="echoid-s13911" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div718" type="section" level="1" n="215"> <head xml:id="echoid-head436" xml:space="preserve">XXI.</head> <p> <s xml:id="echoid-s13912" xml:space="preserve">La voûte bien achevée & </s> <s xml:id="echoid-s13913" xml:space="preserve">couverte, on la laiſſera ceintrée pen-<lb/>dant cinq ou ſix mois, pour donner le tems au mortier de ſe con-<lb/>ſolider & </s> <s xml:id="echoid-s13914" xml:space="preserve">faire corps avec les briques; </s> <s xml:id="echoid-s13915" xml:space="preserve">après quoi on la déceintrera <lb/>tout doucement par travée, & </s> <s xml:id="echoid-s13916" xml:space="preserve">non tout à la fois; </s> <s xml:id="echoid-s13917" xml:space="preserve">on la reparera <lb/>en tous les lits & </s> <s xml:id="echoid-s13918" xml:space="preserve">les joints avec bon mortier blanc & </s> <s xml:id="echoid-s13919" xml:space="preserve">reciré; </s> <s xml:id="echoid-s13920" xml:space="preserve">on <lb/>déblayera les bois & </s> <s xml:id="echoid-s13921" xml:space="preserve">les décombres, faiſant place nette.</s> <s xml:id="echoid-s13922" xml:space="preserve"/> </p> <pb o="73" file="0623" n="675" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> </div> <div xml:id="echoid-div719" type="section" level="1" n="216"> <head xml:id="echoid-head437" xml:space="preserve">XXII.</head> <p> <s xml:id="echoid-s13923" xml:space="preserve">Enſuite on mettra tout le ſolle ou aire du Magaſin bien dreſſé, bat-<lb/>tu, & </s> <s xml:id="echoid-s13924" xml:space="preserve">de niveau un pied plus haut quele rez-de-chauſſée, ſur lequel <lb/>on poſera des poutrelles de huit pouces quarrés, ſoit en longrines, ou <lb/>en traverſines, de deux pieds de milieu en milieu, en ſorte qu’il ne <lb/>reſte plus que ſeize pouces d’intervalle entr’elles, dont la hauteur <lb/>ſera arraſée avec des eſcarbilles, ou mâche-fer provenant des for-<lb/>ges des ſerruriers ou marêchaux; </s> <s xml:id="echoid-s13925" xml:space="preserve">& </s> <s xml:id="echoid-s13926" xml:space="preserve">après les avoir bien arran-<lb/>gés & </s> <s xml:id="echoid-s13927" xml:space="preserve">battus pour remplir tous les vuides, on remettra du charbon <lb/>de bois juſqu’à fleur du deſſus deſdites poutrelles, ſur leſquelles on <lb/>poſera le plancher de madriers au moins de deux pouces d’épaiſſeur <lb/>bien chevillés, & </s> <s xml:id="echoid-s13928" xml:space="preserve">proprement joints enſemble, ainſi que les chan-<lb/>tiers pour ranger les barriques, & </s> <s xml:id="echoid-s13929" xml:space="preserve">le tout de bon bois de chêne bien <lb/>ſec, ſans aubier, ni gerſures, lequel plancher ſera tenu un pied <lb/>plus haut que le rez-de-chauſſée, par lequel on montera par deux <lb/>marches de ſix pouces chacune, faiſant les ſeüils des deux portes <lb/>avec battée par le bas, pour qu’on n’y puiſſe pas introduire du feu.</s> <s xml:id="echoid-s13930" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div720" type="section" level="1" n="217"> <head xml:id="echoid-head438" xml:space="preserve">XXIII.</head> <p> <s xml:id="echoid-s13931" xml:space="preserve">Paver ſur ſix pieds de large tout autour dudit Magaſin avec des <lb/>carreaux de grès de ſept à huit pouces quarrés à leur face, ſur <lb/>huit à dix de queuë, poſés ſur un couchis ou forme de ſable de huit <lb/>à neuf pouces de hauteur, bien battus au refus de la demoiſelle, <lb/>& </s> <s xml:id="echoid-s13932" xml:space="preserve">mis en pente de ſix pouces depuis le parement des gros murs <lb/>allant vers le petit mur d’enceinte, qui doit être un pied & </s> <s xml:id="echoid-s13933" xml:space="preserve">demi <lb/>ou deux pieds plus bas avec de petites ouvertures ou tuyaux de <lb/>deux ou trois pouces, pour ſervir d’écoulement aux eaux qui tom-<lb/>beront des égouts des toits, pour éviter les humidités; </s> <s xml:id="echoid-s13934" xml:space="preserve">& </s> <s xml:id="echoid-s13935" xml:space="preserve">ſi ledit <lb/>pavé étoit poſé en bon mortier de ciment, il ſeroit encore meilleur.</s> <s xml:id="echoid-s13936" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div721" type="section" level="1" n="218"> <head xml:id="echoid-head439" xml:space="preserve">XXIV.</head> <p> <s xml:id="echoid-s13937" xml:space="preserve">Ledit petit mur d’enceinte, ou d’enveloppe, ſera fondé ſolide-<lb/>ment avec deux retraites de trois pouces de part & </s> <s xml:id="echoid-s13938" xml:space="preserve">d’autre, & </s> <s xml:id="echoid-s13939" xml:space="preserve">ré-<lb/>duit enſuite à un pied & </s> <s xml:id="echoid-s13940" xml:space="preserve">demi d’épaiſſeur ſur dix à douze pieds de <lb/>hauteur plus ou moins ſelon la ſituation du Magazin, fait en mê-<lb/>mes materiaux que ci-devant.</s> <s xml:id="echoid-s13941" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13942" xml:space="preserve">Toute la maçonnerie qui compoſera ce Magazin, y compris la <lb/>voûte & </s> <s xml:id="echoid-s13943" xml:space="preserve">les angles de pierres de taille, ſera payée à la toiſe cube, <lb/>ſans y comprendre aucun vuide.</s> <s xml:id="echoid-s13944" xml:space="preserve"/> </p> <pb o="74" file="0624" n="676" rhead="LA SCIENCE DES INGENIEURS,"/> <p> <s xml:id="echoid-s13945" xml:space="preserve">La maçonnerie du petit mur d’enceinte ſera payée à la toiſe quar-<lb/>rée d’un pied & </s> <s xml:id="echoid-s13946" xml:space="preserve">demi d’épaiſſeur réduite.</s> <s xml:id="echoid-s13947" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13948" xml:space="preserve">Les terres à la toiſe cube, déblai & </s> <s xml:id="echoid-s13949" xml:space="preserve">remblai compris.</s> <s xml:id="echoid-s13950" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13951" xml:space="preserve">Les bois de charpente payés au cent de ſolives miſes en œuvre.</s> <s xml:id="echoid-s13952" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13953" xml:space="preserve">Les portes à la piece.</s> <s xml:id="echoid-s13954" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13955" xml:space="preserve">Les fenêtres à la piece.</s> <s xml:id="echoid-s13956" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13957" xml:space="preserve">Les gros fers au cent de livres peſant, poids de marc.</s> <s xml:id="echoid-s13958" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13959" xml:space="preserve">Les ſerrures avec leurs clefs & </s> <s xml:id="echoid-s13960" xml:space="preserve">verroüils à la piece, miſes en place.</s> <s xml:id="echoid-s13961" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13962" xml:space="preserve">La tole au cent de livres peſant poids de marc, la poſe & </s> <s xml:id="echoid-s13963" xml:space="preserve">clous <lb/>compris.</s> <s xml:id="echoid-s13964" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13965" xml:space="preserve">Le pavé de grès à la toiſe quarrée ſelon ſa conſtruction. </s> <s xml:id="echoid-s13966" xml:space="preserve">Au ſur-<lb/>plus, on mettra à l’ordinaire toutes les conditions auſquelles on <lb/>voudra obliger les Entrepreneurs, ainſi que de fournir bonne & </s> <s xml:id="echoid-s13967" xml:space="preserve"><lb/>ſuffiſante caution, tant pour la ſûreté des deniers du Roy qui leur <lb/>ſeront délivrés, que pour la garantic de leurs ouvrages un an & </s> <s xml:id="echoid-s13968" xml:space="preserve"><lb/>jour après leur reception.</s> <s xml:id="echoid-s13969" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13970" xml:space="preserve">Comme il n’y a point de maçonnerie nouvellement faite, qui <lb/>ne tace, ou ne faſſe quelque affaiſſement, plus ou moins, ſelon la <lb/>bonne ou mauvaiſe qualité des materiaux, j’eſtime que pour plus <lb/>de ſolidité en la conſtruction d’un Magazin à poudre, d’où peut dé-<lb/>pendre la conſervation ou la perte d’une Place, qu’il ne faudroit <lb/>rien faire avec précipitation, & </s> <s xml:id="echoid-s13971" xml:space="preserve">qu’après que la fondation ſeroit <lb/>miſe à hauteur de la retraite, la couvrir de gros fumier & </s> <s xml:id="echoid-s13972" xml:space="preserve">de terre <lb/>au deſſus miſe en dos d’âne, pour l’écoulement des neiges & </s> <s xml:id="echoid-s13973" xml:space="preserve">eaux <lb/>des pluyes; </s> <s xml:id="echoid-s13974" xml:space="preserve">afin de laiſſer repoſer, affaiſſer, & </s> <s xml:id="echoid-s13975" xml:space="preserve">conſolider les mortiers <lb/>pendant ſix mois, & </s> <s xml:id="echoid-s13976" xml:space="preserve">au printems enſuite la découvrir par un beau <lb/>tems, la bien balayer, repaſſer le niveau par tout; </s> <s xml:id="echoid-s13977" xml:space="preserve">& </s> <s xml:id="echoid-s13978" xml:space="preserve">par après avoir <lb/>rétabli ce qui pourroit y avoir de dégradé, elever les murs au deſ-<lb/>ſus juſqu’à la naiſſance de la voûte, en les arraſant toûjours à mê-<lb/>me hauteur, après quoi les couvrir & </s> <s xml:id="echoid-s13979" xml:space="preserve">laiſſer repoſer comme ci-de-<lb/>vant; </s> <s xml:id="echoid-s13980" xml:space="preserve">l’année enſuite faire la voûte avec toutes ſes appartenances, <lb/>la couvrir de tuile ou d’ardoiſe, & </s> <s xml:id="echoid-s13981" xml:space="preserve">ne la déceintrer que ſix mois <lb/>après, & </s> <s xml:id="echoid-s13982" xml:space="preserve">toûjours par petites travées pour ne lui pas cauſer de grands <lb/>ébranlemens, ainſi que cela eſt arrivé à quelques endroits que la <lb/>bienſeance ne permet pas de citer; </s> <s xml:id="echoid-s13983" xml:space="preserve">faire enſuite ſon plancher avec <lb/>les chantiers & </s> <s xml:id="echoid-s13984" xml:space="preserve">ſon mur d’enceinte ou d’enveloppe.</s> <s xml:id="echoid-s13985" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13986" xml:space="preserve">Fait à Saint Quentin, le 22. </s> <s xml:id="echoid-s13987" xml:space="preserve">Janvier 1729. </s> <s xml:id="echoid-s13988" xml:space="preserve">DE MUZ.</s> <s xml:id="echoid-s13989" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s13990" xml:space="preserve">Voicile Devis de la Citerne de Calais que j’ai promis dans le qua-<lb/>triéme Livre; </s> <s xml:id="echoid-s13991" xml:space="preserve">il ne contient rien de particulier dont je n’aye fait <lb/>mention en parlant de la Citerne de Charlemont, mais il ſervira <lb/>d’exemple, & </s> <s xml:id="echoid-s13992" xml:space="preserve">pourra avoir ſon utilité.</s> <s xml:id="echoid-s13993" xml:space="preserve"/> </p> <pb o="75" file="0625" n="677" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> </div> <div xml:id="echoid-div722" type="section" level="1" n="219"> <head xml:id="echoid-head440" xml:space="preserve">DEVIS DE CE QUI EST A FAIRE ET A OBSER VER <lb/>pour la Conſtruction d’une Citerne qui recevra les Eaux <lb/>de Pluye qui tombent ſur l’Egliſe Paroiſſiale de Calais.</head> <head xml:id="echoid-head441" style="it" xml:space="preserve">PREMIEREMENT.</head> <head xml:id="echoid-head442" xml:space="preserve"><emph style="sc">Remuement des</emph> <emph style="sc">Terres</emph>.</head> <p> <s xml:id="echoid-s13994" xml:space="preserve">A Près que les alignemens auront eté tracés à I’Entrepreneur, <lb/> <anchor type="note" xlink:label="note-0625-01a" xlink:href="note-0625-01"/> pour faire l’excavation & </s> <s xml:id="echoid-s13995" xml:space="preserve">la foüille des terres qu’il faudra ôter, <lb/>il les enlevera juſqu’à la profondeur du deſſus des eaux des puits <lb/>circonvoiſins, les tranſportera & </s> <s xml:id="echoid-s13996" xml:space="preserve">les applanira le plus uniment <lb/>que faire ſe pourra, ſur la partie du cimetiere du côté du midi, <lb/>ſuivant toute ſa longueur & </s> <s xml:id="echoid-s13997" xml:space="preserve">ſa largeur, & </s> <s xml:id="echoid-s13998" xml:space="preserve">ſingulierement dans les <lb/>endroits les plus bas.</s> <s xml:id="echoid-s13999" xml:space="preserve"/> </p> <div xml:id="echoid-div722" type="float" level="2" n="1"> <note position="right" xlink:label="note-0625-01" xlink:href="note-0625-01a" xml:space="preserve"><emph style="sc">Planch</emph>. <lb/>34.</note> </div> <p> <s xml:id="echoid-s14000" xml:space="preserve">Les vieux materiaux provenans de la démolition du petit mur du <lb/>parvis, les pavés, les arbres, & </s> <s xml:id="echoid-s14001" xml:space="preserve">tous autres appartiendront à la Fa-<lb/>brique de ladite Egliſe, qui s’en ſaiſira à meſure de la démoli-<lb/>tion d’iceux, laquelle ſera faite par l’Entrepreneur, & </s> <s xml:id="echoid-s14002" xml:space="preserve">les tranſ-<lb/>portera où bon lui ſemblera, afin que ledit Entrepreneur n’en re-<lb/>çoive point d’embarras après la Conſtruction de ladite Citerne; </s> <s xml:id="echoid-s14003" xml:space="preserve">il <lb/>remblaira derriere la maçonnerie par dehors, & </s> <s xml:id="echoid-s14004" xml:space="preserve">à ſes dépens, les <lb/>trous qu’il conviendra; </s> <s xml:id="echoid-s14005" xml:space="preserve">leſquelles terres il battra avec une batte <lb/>du poids de trente livres, & </s> <s xml:id="echoid-s14006" xml:space="preserve">les mettra en état de recevoir le pavé <lb/>qui ſera fait au tour.</s> <s xml:id="echoid-s14007" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div724" type="section" level="1" n="220"> <head xml:id="echoid-head443" xml:space="preserve"><emph style="sc">Charpente</emph>.</head> <p> <s xml:id="echoid-s14008" xml:space="preserve">Il mettra des madriers ou bordages de bois de chêne de quatre <lb/>pouces d’épaiſſeur ſur toute la largeur de la maçonnerie des murs <lb/>de fondation, leſquels ſeront bien équarris & </s> <s xml:id="echoid-s14009" xml:space="preserve">à vive arête.</s> <s xml:id="echoid-s14010" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div725" type="section" level="1" n="221"> <head xml:id="echoid-head444" xml:space="preserve">MAÇONNERIE.</head> <head xml:id="echoid-head445" xml:space="preserve"><emph style="sc">Qualite’s de la</emph> <emph style="sc">Chaux</emph>.</head> <p> <s xml:id="echoid-s14011" xml:space="preserve">Elle ſera faite avec pierres de la côte de Boulogne du blanc bleu, <lb/>cuites à propos par gens à ce entendus, & </s> <s xml:id="echoid-s14012" xml:space="preserve">éteintes de même; </s> <s xml:id="echoid-s14013" xml:space="preserve">la-<lb/>quelle ſera bien remuée, broüillée, & </s> <s xml:id="echoid-s14014" xml:space="preserve">coulée en baſſin pour être <lb/>mieux détrempée & </s> <s xml:id="echoid-s14015" xml:space="preserve">purgée ſoigneuſement de toutes les pierres qui <pb o="76" file="0626" n="678" rhead="LA SCIENCE DES INGENIEURS,"/> n’auront point été éteintes, ni penetrées par la violence du feu, <lb/>& </s> <s xml:id="echoid-s14016" xml:space="preserve">par conſequent mal cuites.</s> <s xml:id="echoid-s14017" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div726" type="section" level="1" n="222"> <head xml:id="echoid-head446" xml:space="preserve"><emph style="sc">Qualite’s du</emph> <emph style="sc">Sable</emph>.</head> <p> <s xml:id="echoid-s14018" xml:space="preserve">Il ſera du plus pur qui ſe trouvera dans le pays, ſans mélange, & </s> <s xml:id="echoid-s14019" xml:space="preserve"><lb/>paſſé à la claye, laquelle ſera fort fine, afin qu’il ne s’y trouve point <lb/>de galets.</s> <s xml:id="echoid-s14020" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div727" type="section" level="1" n="223"> <head xml:id="echoid-head447" xml:space="preserve"><emph style="sc">Composition du</emph> <emph style="sc">Mortier</emph>.</head> <p> <s xml:id="echoid-s14021" xml:space="preserve">La chaux & </s> <s xml:id="echoid-s14022" xml:space="preserve">le ſable étant preparés, & </s> <s xml:id="echoid-s14023" xml:space="preserve">de la qualité ci-deſſus <lb/>ſpecifiée, le mortier de toute la maçonnerie de brique en ſera <lb/>compoſé, ſçavoir avec deux cinquiémes de chaux & </s> <s xml:id="echoid-s14024" xml:space="preserve">trois cinquié-<lb/>mes de ſable, bien broüillés, & </s> <s xml:id="echoid-s14025" xml:space="preserve">battus à quatre repriſes en quatre <lb/>jours differens avant la miſe en œuvre.</s> <s xml:id="echoid-s14026" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div728" type="section" level="1" n="224"> <head xml:id="echoid-head448" xml:space="preserve"><emph style="sc">Qualite’s de la</emph> <emph style="sc">Brique</emph>.</head> <p> <s xml:id="echoid-s14027" xml:space="preserve">Elle ſera toute de même échantillon, la mieux cuite que faire ſe <lb/>pourra, & </s> <s xml:id="echoid-s14028" xml:space="preserve">faite avec bonne terre bien maniée & </s> <s xml:id="echoid-s14029" xml:space="preserve">bien corroyée, <lb/>& </s> <s xml:id="echoid-s14030" xml:space="preserve">la plus entiere, en ſorte que les morceaux n’ayent pas moins que <lb/>demie brique de long, faute de quoi ils ſeront rebutés ſans être <lb/>mis en œuvre: </s> <s xml:id="echoid-s14031" xml:space="preserve">l’Entrepreneur fera charger & </s> <s xml:id="echoid-s14032" xml:space="preserve">décharger à la main <lb/>ladite brique deſſus les tombereaux & </s> <s xml:id="echoid-s14033" xml:space="preserve">banneaux qui la voitureront, <lb/>afin qu’il y en ait moins de caſſées.</s> <s xml:id="echoid-s14034" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div729" type="section" level="1" n="225"> <head xml:id="echoid-head449" xml:space="preserve"><emph style="sc">Qualite’s du</emph> <emph style="sc">Mortier de</emph> <emph style="sc">Ciment</emph>.</head> <p> <s xml:id="echoid-s14035" xml:space="preserve">Celui qui ſera employé aux renduits & </s> <s xml:id="echoid-s14036" xml:space="preserve">citerneaux, tant du dedans <lb/>que du deſſus, ſera fait avec tuileaux de vieilles tuiles bien cuites, <lb/>ſans qu’il y ſoit employé aucune brique; </s> <s xml:id="echoid-s14037" xml:space="preserve">il ſera bien battu, pulve-<lb/>riſé, & </s> <s xml:id="echoid-s14038" xml:space="preserve">paſſé au tamis du Boulanger, & </s> <s xml:id="echoid-s14039" xml:space="preserve">le mortier fait avec deux <lb/>cinquiémes de chaux vive de Boulogne, & </s> <s xml:id="echoid-s14040" xml:space="preserve">trois cinquiemes dudit <lb/>ciment, le tout bien battu, & </s> <s xml:id="echoid-s14041" xml:space="preserve">démêlé tous les jours conſecutive-<lb/>ment juſqu’à ce qu’il ſoit employé.</s> <s xml:id="echoid-s14042" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14043" xml:space="preserve">Aprés que les materiaux ci-deſſus mentionnés auront été prépa-<lb/>rés ſur les lieux, tels, & </s> <s xml:id="echoid-s14044" xml:space="preserve">de la qualité qu’ils ſont ſpecifiés par les ar-<lb/>ticles précédens de ce Devis, & </s> <s xml:id="echoid-s14045" xml:space="preserve">que l’Entrepreneur aura préparé <lb/>en dernier lieu l’endroit où ſera établi la fondation de ladite Citer-<lb/>ne, ſuivant les alignemens qui lui auront été marqués, & </s> <s xml:id="echoid-s14046" xml:space="preserve">qu’il aura <lb/>creuſé la fondation auſſi bas qu’il ſe pourra, après l’avoir bien éga- <pb o="77" file="0627" n="679" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> liſée, & </s> <s xml:id="echoid-s14047" xml:space="preserve">miſe de niveau, il poſera à l’endroit des murs des madriers <lb/>ou bordages de bois de chêne à vive arête de quatre pouces d’épaiſ-<lb/>ſeur, ſur leſquels la maçonnerie deſdits murs ſera établie, & </s> <s xml:id="echoid-s14048" xml:space="preserve">en mê-<lb/>me tems celle du fond de la Citerne ſuivant les longueurs, hau-<lb/>teurs, & </s> <s xml:id="echoid-s14049" xml:space="preserve">épaiſſeurs marquées au plan & </s> <s xml:id="echoid-s14050" xml:space="preserve">profil qui ſeront joints au <lb/>Devis; </s> <s xml:id="echoid-s14051" xml:space="preserve">toute la maçonnerie du fond de la Citerne, des côtés, & </s> <s xml:id="echoid-s14052" xml:space="preserve">du <lb/>mur du milieu, ſera faite avec bonne brique & </s> <s xml:id="echoid-s14053" xml:space="preserve">chaux de Boulogne, <lb/>ainſi qu’il eſt ci-deſſus ſpecifié, à la reſerve du citernage marqué au <lb/>milieu des murs, qui ſera fait avec quatre aſſiſes de briques poſées <lb/>de plat & </s> <s xml:id="echoid-s14054" xml:space="preserve">à bain de ciment dans toute l’étenduë du fond, obſervant <lb/>de recouvrir chaque lit de ciment bien & </s> <s xml:id="echoid-s14055" xml:space="preserve">proprement étendu & </s> <s xml:id="echoid-s14056" xml:space="preserve"><lb/>repaſſé à la truelle, en ſorte qu’il ne reſte pas la moindre apparence <lb/>de joints, ce qui ſera repeté autant de fois qu’il y aura de lits de <lb/>briques; </s> <s xml:id="echoid-s14057" xml:space="preserve">le citernage des côtés ſera auſſi de briques, mais poſées <lb/>de cant & </s> <s xml:id="echoid-s14058" xml:space="preserve">en liaiſon l’une après l’autre, & </s> <s xml:id="echoid-s14059" xml:space="preserve">chaque lit recouvert & </s> <s xml:id="echoid-s14060" xml:space="preserve"><lb/>renduit de ciment foüetté, liſſé, & </s> <s xml:id="echoid-s14061" xml:space="preserve">repaſſé à la truelle autant de <lb/>fois auſſi qu’il y aura d’aſſiſes de briques. </s> <s xml:id="echoid-s14062" xml:space="preserve">Comme ce citernage eſt <lb/>très important, l’Entrepreneur aura un ſoin très particulier qu’il <lb/>ſoit bien fait, & </s> <s xml:id="echoid-s14063" xml:space="preserve">y veillera ſans ceſſe.</s> <s xml:id="echoid-s14064" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div730" type="section" level="1" n="226"> <head xml:id="echoid-head450" xml:space="preserve"><emph style="sc">Renduits autour du dehors de la</emph> <emph style="sc">Citerne</emph>.</head> <p> <s xml:id="echoid-s14065" xml:space="preserve">En élevant la maçonnerie des pieds droits & </s> <s xml:id="echoid-s14066" xml:space="preserve">des pignons, il ſera <lb/>fait un renduit par le dehors d’icelle, depuis le bord de la fondation <lb/>juſqu’à la hauteur des plus hautes eaux de la mer, lorſqu’elle ſera <lb/>miſe dans le canal qui paſſe au travers de la Ville en cas de beſoin.</s> <s xml:id="echoid-s14067" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14068" xml:space="preserve">Le renduit ſera fait avec chaux de Boulogne & </s> <s xml:id="echoid-s14069" xml:space="preserve">ſable conditionné <lb/>comme celui de la maçonnerie, il aura un pouce d’épaiſſeur, & </s> <s xml:id="echoid-s14070" xml:space="preserve">ſe-<lb/>ra paſſé à la truelle, liſſé & </s> <s xml:id="echoid-s14071" xml:space="preserve">reliſſé pour fermer les gerſures, avec <lb/>un liſſoir de bois ou d’acier bien poli, & </s> <s xml:id="echoid-s14072" xml:space="preserve">en ce faiſant il ſera employé <lb/>un lit de chaux, après quoi les terres ſeront miſes derriere la ma-<lb/>çonnerie pour ne pas laiſſer le tems au ſoleil d’y cauſer de nouvel-<lb/>les gerſures.</s> <s xml:id="echoid-s14073" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14074" xml:space="preserve">Après la conſtruction de la Citerne, & </s> <s xml:id="echoid-s14075" xml:space="preserve">que les voûtes auront été <lb/>déceintrées, les joints du dedans ſeront creuſés & </s> <s xml:id="echoid-s14076" xml:space="preserve">approfondis de <lb/>quatre lignes avec un petit fer recourbé, & </s> <s xml:id="echoid-s14077" xml:space="preserve">les briques du parement <lb/>piquées à la pointe du marteau pour donner plus de tenuë au ci-<lb/>ment, enſuite de quoi on commencera par en foüetter les joints, & </s> <s xml:id="echoid-s14078" xml:space="preserve"><lb/>après les avoir remplis, il ſera fait un enduit par deſſus de l’épaiſſeur <lb/>de dix à douze lignes, lequel ſera battu contre le mur avec des <lb/>liſſoirs de bui, ou de fer bien poli; </s> <s xml:id="echoid-s14079" xml:space="preserve">après quoi on le repaſſera tous <pb o="78" file="0628" n="680" rhead="LA SCIENCE DES INGENIEURS,"/> les jours une fois pendant douze ou quinze jours, juſqu’à ce qu’il <lb/>ſoit parfaitement ſec, l’arroſant à chaque fois de lait de ciment <lb/>avec un bouchon; </s> <s xml:id="echoid-s14080" xml:space="preserve">le mur du milieu ſera renduit de même que <lb/>ceux des côtés, & </s> <s xml:id="echoid-s14081" xml:space="preserve">avant le fond de la Citerne qui ne ſera mis que <lb/>le dernier en état.</s> <s xml:id="echoid-s14082" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14083" xml:space="preserve">Les puits des pompes & </s> <s xml:id="echoid-s14084" xml:space="preserve">les citerneaux ſeront renduits avec la <lb/>même précaution que la ſuſdite Citerne.</s> <s xml:id="echoid-s14085" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14086" xml:space="preserve">Le renduit & </s> <s xml:id="echoid-s14087" xml:space="preserve">le citernement de la clôture ſera fait avec les mé-<lb/>mes ſoins, & </s> <s xml:id="echoid-s14088" xml:space="preserve">avec le même mortier que celui du dedans de la Ci-<lb/>terne, en le relevant de quinze pouces le long des côtés, & </s> <s xml:id="echoid-s14089" xml:space="preserve">diri-<lb/>geant les ruiſſeaux avec pente à une gargoüille qui verſera dans un <lb/>petit citerneau fait exprès.</s> <s xml:id="echoid-s14090" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14091" xml:space="preserve">Après que ce citerneau aura été fait dans les heures du jour que <lb/>l’ardeur du ſoleil dominera le moins, & </s> <s xml:id="echoid-s14092" xml:space="preserve">qu’il fera ſombre, il ſera <lb/>recouvert avec des paillaſſons de roſeaux, qui ſeront levés toutes <lb/>les fois qu’on le reliſſera, & </s> <s xml:id="echoid-s14093" xml:space="preserve">auſſi-tôt remis pour éviter que la gran-<lb/>de précipitation du deſſéchement n’y faſſe de gerſure, s’il ſe fai-<lb/>ſoit en plein ſoleil.</s> <s xml:id="echoid-s14094" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14095" xml:space="preserve">On le couvrira enſuite par un lit de gros ſable tout du long, ſpe-<lb/>cialement dans le ruiſſeau où il faudra le doubler, aprés quoi le <lb/>ſurplus ſera rempli de terres qui ſeront battuës par lits afin de les <lb/>affermir, & </s> <s xml:id="echoid-s14096" xml:space="preserve">recouvertes avec gazon plat.</s> <s xml:id="echoid-s14097" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14098" xml:space="preserve">Aprés quela maçonnerie ſera élevée au niveau du rez-de-chauſ-<lb/>ſée, le pourtour exterieur d’icelle ſera bordé de deux aſſiſes de pier-<lb/>re de taille de douze pouces de hauteur au moins, laquelle ſera de <lb/>la carriere de Landretun, ou de la côte de Boulogne, au choix de <lb/>l’Entrepreneur, dont les pierres ſeront bien dégauchies & </s> <s xml:id="echoid-s14099" xml:space="preserve">propre-<lb/>ment taillées au ciſeau & </s> <s xml:id="echoid-s14100" xml:space="preserve">au poinçon, de huit pouces ſur le plat & </s> <s xml:id="echoid-s14101" xml:space="preserve"><lb/>ſix ſur les joints montans, poſées en liaiſon de ſix pouces au moins <lb/>à côté de chaque, & </s> <s xml:id="echoid-s14102" xml:space="preserve">avec boutiſſes de vingt à vingt-deux pouces <lb/>au moins de queuë & </s> <s xml:id="echoid-s14103" xml:space="preserve">pannereſſes de quatorze à ſeize pouces; </s> <s xml:id="echoid-s14104" xml:space="preserve">le <lb/>ſurplus du parement exterieur de ladite maçonnerie ſera bordé <lb/>du haut en bas & </s> <s xml:id="echoid-s14105" xml:space="preserve">tout au tour de ladite Citerne avec autant d’aſſi-<lb/>ſes que beſoin ſera, de doubles carreaux de Boulogne bien épincés, <lb/>& </s> <s xml:id="echoid-s14106" xml:space="preserve">proprement mis en œuvre avec les plus petits joints qu’il ſera <lb/>poſſible, leſquelles aſſiſes ſeront poſées de niveau & </s> <s xml:id="echoid-s14107" xml:space="preserve">en bain de <lb/>mortier de la même qualité que celui de la pierre de taille; </s> <s xml:id="echoid-s14108" xml:space="preserve">le mê-<lb/>me Entrepreneur fera auſſi les auges, puits, marſelles, & </s> <s xml:id="echoid-s14109" xml:space="preserve">citernaux <lb/>avec des entrées dans la Citerne, & </s> <s xml:id="echoid-s14110" xml:space="preserve">petites guerites ſervant de cou-<lb/>vertures & </s> <s xml:id="echoid-s14111" xml:space="preserve">de fenêtres audit puits, à quoi il ſera employé la pierre <lb/>de taille néceſſaire, & </s> <s xml:id="echoid-s14112" xml:space="preserve">le tout toiſé à la toiſe cube, de même que la <lb/>maçonnerie de brique.</s> <s xml:id="echoid-s14113" xml:space="preserve"/> </p> <pb o="79" file="0629" n="681" rhead="LIV. VI. DE LA MANIERE DE FAIRE LES DEVIS."/> <p> <s xml:id="echoid-s14114" xml:space="preserve">Les citerneaux auront trois pieds de diamettre dans œuvre, & </s> <s xml:id="echoid-s14115" xml:space="preserve">les <lb/>auges ſeront traverſés de barreaux de fer pour poſer les ſeaux deſſus, <lb/>quand on voudra les remplir d’eau; </s> <s xml:id="echoid-s14116" xml:space="preserve">il ſera fait un petit cordon de <lb/>pierre de taille au tour de ladite Citerne à quatre pieds au deſ-<lb/>ſous du courronnement du parapet, dont le parement ſera fait avec <lb/>doubles carreaux de Boulogne, & </s> <s xml:id="echoid-s14117" xml:space="preserve">recouvert par deſſus avec une <lb/>tablette de ſix pouces d’épaiſſeur, de douze à quinze pouces de queuë <lb/>pour les pannereſſes, & </s> <s xml:id="echoid-s14118" xml:space="preserve">de dix-huit à vingt pour les boutiſſes, la-<lb/>quelle ſera de pierres de taille de la carriere de Landretun, ou de <lb/>la côte d’Embleteuze, au choix de l’Entrepreneur, proprement <lb/>taillées au ciſeau & </s> <s xml:id="echoid-s14119" xml:space="preserve">au poinçon, & </s> <s xml:id="echoid-s14120" xml:space="preserve">poſées en bain de mortier de ci-<lb/>ment conditionné comme ci-deſſus, ayant deux pouces de ſaillie, <lb/>& </s> <s xml:id="echoid-s14121" xml:space="preserve">un pouce de pente ſur pied par le deſſus.</s> <s xml:id="echoid-s14122" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14123" xml:space="preserve">Le deſſus du parapet ſera fait avec bonnes briques poſées en liai-<lb/>ſon & </s> <s xml:id="echoid-s14124" xml:space="preserve">en bain de mortier de Boulogne, & </s> <s xml:id="echoid-s14125" xml:space="preserve">le couronnement d’icelui, <lb/>ſauf la tablette, fait avec briques poſées de bout & </s> <s xml:id="echoid-s14126" xml:space="preserve">de cant avec <lb/>pareille pente que celle de ladite tablette, & </s> <s xml:id="echoid-s14127" xml:space="preserve">aſſiſes en bain de mor-<lb/>tier & </s> <s xml:id="echoid-s14128" xml:space="preserve">de ciment.</s> <s xml:id="echoid-s14129" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14130" xml:space="preserve">Le gravier qui ſera mis ſur la teiture ainſi qu’il a été dit dans les <lb/>citerneaux, ſera du galet du plus fin & </s> <s xml:id="echoid-s14131" xml:space="preserve">du plus délié, de celui du ban <lb/>de pierretes hors de la baſſe Ville, après avoir été paſſé à la claye <lb/>fort fine & </s> <s xml:id="echoid-s14132" xml:space="preserve">fort déliée, & </s> <s xml:id="echoid-s14133" xml:space="preserve">enſuite lavé & </s> <s xml:id="echoid-s14134" xml:space="preserve">relavé avec de l’eau <lb/>douce, juſqu’à ce qu’il la rende auſſi claire qu’il l’aura reçûë, après <lb/>quoi il ſera apporté dans des tonneaux recouverts pour empêcher <lb/>qu’il ne s’y communique aucune ſaleté, avant que d’être mis ſur la-<lb/>dite teiture & </s> <s xml:id="echoid-s14135" xml:space="preserve">dans leſdits citerneaux.</s> <s xml:id="echoid-s14136" xml:space="preserve"/> </p> </div> <div xml:id="echoid-div731" type="section" level="1" n="227"> <head xml:id="echoid-head451" xml:space="preserve"><emph style="sc">Pave</emph>’.</head> <p> <s xml:id="echoid-s14137" xml:space="preserve">Ledit Entrepreneur fera le pavé neceſſaire au dehors de ladite <lb/>Citerne, lequel ſera de la côte de Boulogne, bien épincé, de ſix à <lb/>huit pouces de queuë, poſé par routes ſur douze à quinze pouces <lb/>d’épaiſſeur de ſable avec les pentes neceſſaires; </s> <s xml:id="echoid-s14138" xml:space="preserve">obſervant de le <lb/>battre avec la demoiſelle par deux repriſes.</s> <s xml:id="echoid-s14139" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14140" xml:space="preserve">Il livrera & </s> <s xml:id="echoid-s14141" xml:space="preserve">mettra en place les tuyaux de plomb, chaîneaux, & </s> <s xml:id="echoid-s14142" xml:space="preserve"><lb/>cuvettes neceſſaires pour la conduite des eaux dans ladite Citerne.</s> <s xml:id="echoid-s14143" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14144" xml:space="preserve">Il fournira auſſi la ſoudure néceſſaire pour ſouder leſdits tuyaux, <lb/>il livrera & </s> <s xml:id="echoid-s14145" xml:space="preserve">mettra en œuvre tout le fer blanc néceſſaire aux tuyaux, <lb/>chaîneaux, & </s> <s xml:id="echoid-s14146" xml:space="preserve">autres endroits, au cas qu’il ſoit trouvé à propos d’y <lb/>en employer; </s> <s xml:id="echoid-s14147" xml:space="preserve">il livrera pareillement les ferrures des pompes, gonds, <lb/>& </s> <s xml:id="echoid-s14148" xml:space="preserve">autres choſes néceſſaires à les mettre en place. </s> <s xml:id="echoid-s14149" xml:space="preserve">S’il eſt jugé à pro- <pb o="80" file="0630" n="682" rhead="LA SCIENCE DES INGENIEURS."/> pos par l’Ingenieur en chef d’augmenter ou diminuer les épaiſſeurs <lb/>de la maçonnerie, l’Entrepreneur ne pourra pas prétendre qu’il <lb/>ſoit rien changé aux dimenſions de la toiſe cube d’icelle, ni qu’il <lb/>lui ſoit rien payé de ſurplus, au cas qu’il y eût donné de plus gran-<lb/>des épaiſſeurs que celles portées par le plan & </s> <s xml:id="echoid-s14150" xml:space="preserve">profil ci-joint; </s> <s xml:id="echoid-s14151" xml:space="preserve">& </s> <s xml:id="echoid-s14152" xml:space="preserve">au <lb/>cas qu’il les eût diminuées, cette diminution lui ſera déduite ſur le <lb/>toiſé. </s> <s xml:id="echoid-s14153" xml:space="preserve">Tous les ſuſdits ouvrages ſeront rendus faits & </s> <s xml:id="echoid-s14154" xml:space="preserve">parfaits dans <lb/>le quinziéme d’Août prochain, ſujets à viſites, reception, & </s> <s xml:id="echoid-s14155" xml:space="preserve">toiſé. <lb/></s> <s xml:id="echoid-s14156" xml:space="preserve">Sçavoir,</s> </p> <p> <s xml:id="echoid-s14157" xml:space="preserve">Les terres à la toiſe cube une fois en déblai ſeulement.</s> <s xml:id="echoid-s14158" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14159" xml:space="preserve">La charpente du bois de chêne miſe en œuvre au cent de ſolives.</s> <s xml:id="echoid-s14160" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14161" xml:space="preserve">La maçonnerie à la toiſe cube y compris les renduits interieurs & </s> <s xml:id="echoid-s14162" xml:space="preserve"><lb/>exterieurs.</s> <s xml:id="echoid-s14163" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14164" xml:space="preserve">Toute la pierre de taille, & </s> <s xml:id="echoid-s14165" xml:space="preserve">la graiſſerie de doubles carreaux, <lb/>ſans que l’Entrepreneur puiſſe rien prétendre pour le vuide des <lb/>voûtes, ni pour les frais de la charpente des ceintres qu’il fera à ſes <lb/>dépens.</s> <s xml:id="echoid-s14166" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14167" xml:space="preserve">Le galet mis ſur la teiture & </s> <s xml:id="echoid-s14168" xml:space="preserve">dans les citerneaux conditionnés, <lb/>comme il eſt dit au Devis ci-deſſus, auſſi à la toiſe cube.</s> <s xml:id="echoid-s14169" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14170" xml:space="preserve">Le pavé de graiſſerie au tour de ladite Citerne, à la toiſe quarrée.</s> <s xml:id="echoid-s14171" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14172" xml:space="preserve">Le plomb mis en œuvre au cent peſant poids de Paris.</s> <s xml:id="echoid-s14173" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14174" xml:space="preserve">La ſoudure auſſi à la livre & </s> <s xml:id="echoid-s14175" xml:space="preserve">au même poids.</s> <s xml:id="echoid-s14176" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14177" xml:space="preserve">Le fer blanc au pied quarré mis en œuvre.</s> <s xml:id="echoid-s14178" xml:space="preserve"/> </p> <p> <s xml:id="echoid-s14179" xml:space="preserve">La ferrure des pompes, gonds, & </s> <s xml:id="echoid-s14180" xml:space="preserve">autres ouvrages, au cent de <lb/>livres peſant, & </s> <s xml:id="echoid-s14181" xml:space="preserve">au même poids; </s> <s xml:id="echoid-s14182" xml:space="preserve">& </s> <s xml:id="echoid-s14183" xml:space="preserve">ſeront payés,</s> </p> <note position="right" xml:space="preserve"># Liv. # ſols. <lb/>Les terres, à # 3. # 10. <lb/>Le cent de ſolives de bois de chêne, # 305. <lb/>La toiſe cube de maçonnerie, # 61. <lb/>La toiſe cube de galets, # 18. <lb/>La toiſe quarrée de pavé, # 7. <lb/>Le cent de plomb, # 20. <lb/>La livre de ſoudure, # # 12. <lb/>Le pied quarré de fer blanc, # # 14. <lb/>Le cent de gros fer, # 18. <lb/></note> <p> <s xml:id="echoid-s14184" xml:space="preserve">Je crois qu’en voilà aſſez ſur les Devis: </s> <s xml:id="echoid-s14185" xml:space="preserve">ce ſeroit vouloir groſſir ce <lb/>Livre mal-à-propos, que d’en rapporter un plus grand nombre; </s> <s xml:id="echoid-s14186" xml:space="preserve">on <lb/>trouvera à la fin du ſecond Volume tous ceux qui peuvent appar-<lb/>tenir à l’Architecture Hydraulique.</s> <s xml:id="echoid-s14187" xml:space="preserve"/> </p> <p style="it"> <s xml:id="echoid-s14188" xml:space="preserve">Fin du ſixiéme & </s> <s xml:id="echoid-s14189" xml:space="preserve">dernier Livre du premier Volume.</s> <s xml:id="echoid-s14190" xml:space="preserve"/> </p> <pb file="0631" n="683"/> </div> <div xml:id="echoid-div732" type="section" level="1" n="228"> <head xml:id="echoid-head452" xml:space="preserve">TABLE <lb/>DES CHAPITRES</head> <head xml:id="echoid-head453" xml:space="preserve">ET DES PRINCIPAUX SUJETS</head> <head xml:id="echoid-head454" style="it" xml:space="preserve">CONTENUS</head> <head xml:id="echoid-head455" xml:space="preserve">DANS CE PREMIER VOLUME.</head> <head xml:id="echoid-head456" xml:space="preserve">LIVRE PREMIER.</head> <p style="it"> <s xml:id="echoid-s14191" xml:space="preserve">Où l’on enſeigne la maniere de ſe ſervir des principes de la <lb/>mécanique pour donner les dimenſions qui conviennent <lb/>aux revêtemens des ouvrages de Fortification, pour être <lb/>en équilibre avec la pouſſée des terres qu’ils ont à ſoûtenir.</s> <s xml:id="echoid-s14192" xml:space="preserve"/> </p> <note style="it" position="right" xml:space="preserve"> <lb/><emph style="sc">CHapitre</emph> Premier. Où l’on donne la maniere de trouver <lb/># les centres de gravité de pluſieurs Figures, page # 5 <lb/><emph style="sc">Chap</emph>. II. Où l’on enſeigne comme on trouve l’épaiſſeur des murs <lb/># que l’on veut mettre en équilibre par leur réſiſtance avec les <lb/># puiſſances qui agiſſent pour les renverſer lorſque ces murs ſont <lb/># élevés à plomb des deux côtés. # 11 <lb/><emph style="sc">Chap</emph>. III. Où l’on détermine quelle épaiſſeur il faut donner <lb/># au ſommet des murs qui ſont élevés à plomb d’un côté & <lb/># en talud de l’autre, pour que ces murs puiſſent eſtre en <lb/># équilibre par leur réſiſtance avec la pouſſée qu’ils ont à <lb/># ſoûtenir. # 16 <lb/><emph style="sc">Chap</emph>. IV. De la maniere de calculer la pouſſée des terrres <pb file="0632" n="684" rhead="TABLE"/> # que ſoûtiennent les revêtemens de Terraſſes & de Remparts, <lb/># afin de ſavoir l’épaiſſeur qu’il faut leur donner. # 29 <lb/># Vſage d’une Table pour trouver l’épaiſſeur qu’il faut donner <lb/># aux revêtemens de Terraſſes & à ceux des Remparts de For-<lb/># tification. # 43 <lb/><emph style="sc">Chap</emph>. V. De la conſideration des murs qui ont des contre-<lb/># forts. # 50 <lb/># Paralelle du Profil general de Mr. de Vauban, avec les Re-<lb/># gles des Chapitres précedens. # 67 <lb/></note> </div> <div xml:id="echoid-div733" type="section" level="1" n="229"> <head xml:id="echoid-head457" xml:space="preserve">LIVRE SECOND.</head> <p style="it"> <s xml:id="echoid-s14193" xml:space="preserve">Qui traite de la mécanique des Voutes, pour montrer com-<lb/>me s’en fait la pouſſée & </s> <s xml:id="echoid-s14194" xml:space="preserve">la maniere de déterminer l’é-<lb/>paiſſeur de leurs Pié-droits.</s> <s xml:id="echoid-s14195" xml:space="preserve"/> </p> <note style="it" position="right" xml:space="preserve"> <lb/><emph style="sc">CHapitre</emph> I. Où l’on enſeigne comme ſe fait la pouſſée des <lb/># Voutes, & où l’on raporte quelques principes tirés de la méca-<lb/># nique pour en faciliter l’intelligence. # 2 <lb/><emph style="sc">Chap</emph>. II. De la maniere de calculer l’épaiſſeur des Pié-droits <lb/># des Voutes en plain ceintre pour eſtre en équilibre par leur ré-<lb/># ſiſtance avec la pouſſée qu’ils ont à ſoûtenir. # 10 <lb/><emph style="sc">Chap</emph>. III. De la maniere de trouver l’épaiſſeur des Pié-droits <lb/># des Voutes ſurbaiſſées, en tiers-points, en platte-bande, & cel-<lb/># le de culées des Ponts de maçonnerie. # 30 <lb/># Table pour connoître la portée des Vouſſoirs, depuis leur in-<lb/># trados à leur extrados, pour toute ſorte de grandeur d’Arche. # 52 <lb/><emph style="sc">Chap</emph>. IV. Qui comprend des Régles pour trouver l’épaiſ-<lb/># ſeur des Voutes de toute ſorte d’eſpece par le ſeul calcul <lb/># des nombres, pour l’intelligence de ceux qui ne ſavent pas <lb/># l’Algebre. # 54 <lb/></note> <pb file="0633" n="685" rhead="TABLE"/> </div> <div xml:id="echoid-div734" type="section" level="1" n="230"> <head xml:id="echoid-head458" xml:space="preserve">LIVRE TROISIE’ME.</head> <p style="it"> <s xml:id="echoid-s14196" xml:space="preserve">Qui comprend la connoiſſance des matériaux, leur pro-<lb/>prieté, leur détail, & </s> <s xml:id="echoid-s14197" xml:space="preserve">la maniere de <lb/>les mettre en œuvre.</s> <s xml:id="echoid-s14198" xml:space="preserve"/> </p> <note style="it" position="right" xml:space="preserve"> <lb/><emph style="sc">CHapitre</emph> I. Où l’on fait voir les proprietés des diffe-<lb/># rentes ſortes de Pierres dont on ſe ſert pour bâtir. # 2 <lb/><emph style="sc">Chap</emph>. II. Où l’on conſidere les qualités de la Brique & la <lb/># maniere de la fabriquer. # 5 <lb/><emph style="sc">Chap</emph>. III. Où l’on fait voir les qualités de la Chaux & la ma-<lb/># niere de l’éteindre. # 7 <lb/><emph style="sc">Chap</emph>. IV. Où l’on explique les qualités du Sable, de la Poſſo-<lb/># lanne, & du Plâtre. # 9 <lb/><emph style="sc">Chap</emph>. V. De la compoſition du Mortier. # 14 <lb/><emph style="sc">Chap</emph>. VI. Des détails qui ont raport à la conſtruction de la <lb/># Maçonnerie. # 22 <lb/># Table de la Péſanteur d’un pied cube de pluſieurs Matieres. # 25 <lb/># Détail de la Chaux & du Sable. # 26 <lb/># Détail de la Brique. # ibid. <lb/># Détail du Moîlon. # 27 <lb/><emph style="sc">Chap</emph>. VII. Qui comprend pluſieurs Inſtructions ſur l’établiſſe-<lb/># ment & la conduite des Travaux. # 29 <lb/><emph style="sc">Chap</emph>. VIII. Du tranſport & remuëment des Terres. # 35 <lb/><emph style="sc">Chap</emph>. IX. De la maniere de faire les Fondemens des Edifices <lb/># dans toute ſorte d’endroits & principalement dans le mauvais <lb/># terrein. # 47 <lb/><emph style="sc">Chap</emph>. X. Où l’on enſeigne comme l’on doit employer les Mate-<lb/># riaux qui compoſent la Maçonnerie. # 67 <lb/># Explication de pluſieurs Tables ſervant à déterminer les Di-<lb/># menſions de toute ſorte de Revêtement de Maçonnerie. # 74 <lb/><emph style="sc">Chap</emph>. XI. De la conſtruction de Soûterrains, & comme l’on <pb file="0634" n="686" rhead="TABLE."/> # applique ſur leur Voute les Chapes de Ciment. # 79 <lb/><emph style="sc">Chap</emph>. XII. De la maniere de conſtruire les Ouvrages de Ter-<lb/># raſſes. # 84 <lb/># Reglement de Monſieur le Marêchal de Vauban, pour la Con-<lb/># duite des Travaux. # 90 <lb/></note> </div> <div xml:id="echoid-div735" type="section" level="1" n="231"> <head xml:id="echoid-head459" xml:space="preserve">LIVRE QUATRIE’ME.</head> <head xml:id="echoid-head460" style="it" xml:space="preserve">Qui traite de la Conſtruction des Edifices <lb/>Militaires & Civils.</head> <note style="it" position="right" xml:space="preserve"> <lb/><emph style="sc">CHapitre</emph> I. Des qualités du Bois qui entre dans la Char-<lb/># pente. # 2 <lb/><emph style="sc">Chap</emph>. II. Où l’on fait voir la maniere de calculer ou d’eſtimer <lb/># la force des principales Piéces de Charpente qui s’employent <lb/># dans les Bâtimens. # 7 <lb/># Principes ſur la Réſiſtance du Bois en general. # 8 <lb/><emph style="sc">Chap</emph>. III. Où l’on raporte pluſieurs Experiences faites ſur la <lb/># Force du Bois que l’on aplique enſuite à l’uſage qu’on en peut <lb/># faire dans la conſtruction des Edifices. # 15 <lb/><emph style="sc">Chap</emph>. IV. Des bonnes & mauvaiſes qualités du Fer. # 31 <lb/><emph style="sc">Chap</emph>. V. Des Portes que l’on fait aux Villes de Guerre. # 35 <lb/># Conſtruction de la Sinuſoïde. # 41 <lb/># Application de la Sinuſoïde aux Ponts-Levis qui ſervent à fer-<lb/># mer l’entrée des Villes. # 43 <lb/><emph style="sc">Chap</emph>. VI. Des Ponts dormans qui ſervent à faciliter l’entrée <lb/># des Villes de Guerre. # 49 <lb/><emph style="sc">Chap</emph> VII. Des Corps de Garde en general, des Guerites, & <lb/># des Latrines. # 56 <lb/><emph style="sc">Chap</emph>. VIII. De la diſtribution des Ruës dans les Villes de Guer-<lb/># re. # 59 <lb/><emph style="sc">Chap</emph>. IX. Des Magaſins à Poudre, & Arſenaux pour les Mu-<lb/># nitions de Guerre. # 62 <lb/><emph style="sc">Chap</emph>. X. Des Cazernes, de l’Hôpital, de la Priſon, & <pb file="0635" n="687" rhead="TABLE"/> # des Maiſons de Bourgeois. # 72 <lb/># Reglemens pour les Particuliers qui bâtiſſent dans une Place <lb/># neuve. # 77 <lb/><emph style="sc">Chap</emph>. XI. De la Cantine, de la Glaciere, de la Boulangerie, & <lb/># des Moulins à moudre le Bled. # 79 <lb/><emph style="sc">Chap</emph>. XII. De la Conſtruction des Puits & Citernes. # 82 <lb/><emph style="sc">Chap</emph>. XIII. Où l’on donne les Règles generales que l’on doit <lb/># obſerver dans la Conſtruction des Bâtimens. # 88 <lb/><emph style="sc">Chap</emph>. XIV. Qui comprend pluſieurs Détails neceſſaires à l’e-<lb/># xecution des Bâtimens. # 97 <lb/># Détail de la Charpente, des Combles, des Planchers, de la <lb/># Menuiſerie des Portes & Fenêtres. # ibid. <lb/># Détail des Couvertures de Thuile & d’Ardoiſe. # 99 <lb/># Détail de la Vitrerie. # 102 <lb/># Détail du Pavé de Grais, de celui de Brique & de Carreaux. # 103 <lb/></note> </div> <div xml:id="echoid-div736" type="section" level="1" n="232"> <head xml:id="echoid-head461" xml:space="preserve">LIVRE CINQUIE’ ME.</head> <head xml:id="echoid-head462" style="it" xml:space="preserve">Où l’on enſeigne tout ce qui peut appartenir à la Dé-<lb/>coration des Edifices.</head> <note style="it" position="right" xml:space="preserve"> <lb/><emph style="sc">EXplication</emph> des Termes propres aux Ordres d’ Architec-<lb/># ture. # 6 <lb/><emph style="sc">Chap</emph>. I. Où l’on explique les proprietés des Monlures & de leurs <lb/># Ornemens. # 9 <lb/><emph style="sc">Chap</emph>. II. De la connoiſſance des cinq Ordres en general. # 12 <lb/><emph style="sc">Chap</emph>. III. de l’Ordre Toſcan. # 15 <lb/><emph style="sc">Chap</emph>. IV. De l’Ordre Dorique. # 18 <lb/><emph style="sc">Chap</emph>. V. De l’Ordre Ionique. # 22 <lb/># Maniere de tracer la Volute Ionique. # 27 <lb/><emph style="sc">Chap</emph>. VI. De l’Ordre Corinthien. # 29 <lb/><emph style="sc">Chap</emph>. VII. De l’Ordre Compoſite. # 33 <lb/># Remarques ſur les cinq Ordres en general, ſuivies de l’Expli-<lb/># cation de quelques Fragmens des plus beaux Edifices antiques <pb file="0636" n="688" rhead="TABLE."/> # de Rome. # 37 <lb/><emph style="sc">Chap</emph>. VIII. Des Colomnes & de leurs Diminutions, des Perſi-<lb/># ques & des Cariatides. # 44 <lb/># Maniere de renfler les Colomnes. # 45 <lb/><emph style="sc">Chap</emph>. IX. De la Proportion des Pilaſtres & des Frontons. # 49 <lb/><emph style="sc">Chap</emph>. X. Des Periſtiles ou Colomnates, des Arcades, & des <lb/># Niches. # 55 <lb/><emph style="sc">Chap</emph>. XI. De l’Aſſemblage des Ordres, ou de pluſieurs Ordres <lb/># mis les uns ſur les autres. # 60 <lb/><emph style="sc">Chap</emph>. XII. De la Diſtribution & de la Décoration des Edifices <lb/># en general. # 68 <lb/></note> </div> <div xml:id="echoid-div737" type="section" level="1" n="233"> <head xml:id="echoid-head463" xml:space="preserve">LIVRE SIXIE’ME.</head> <head xml:id="echoid-head464" style="it" xml:space="preserve">Qui comprend la Maniere de faire les Devis pour la Conſ-<lb/>truction des Fortifications, & celle des Bâtimens Civils.</head> <note style="it" position="right" xml:space="preserve"> <lb/>MOdele de Devis pour une Place neuve telle que le Neuf-<lb/># Briſack. # 5 <lb/>Dimenſions des Parties Principales de la Place. # 6 <lb/>Qualité & Façon des Materiaux qui ſeront employés auſdits <lb/># Ouvrages. # 19 <lb/>Conſtruction des Ouvrages de Fortiſication. # 23 <lb/>Conditions élementaires du Devis d’un Bâtiment Civil. # 41 <lb/>De la Forme des Adjudications, des Formalités qu’on y obſerve, <lb/># & du Stile dans lequel elles ſont conçûës. # 46 <lb/>Devis & Conditions des Cazernes qui ont été conſtruites à Bethu-<lb/># ne en 1728. # 51 <lb/>Memoire pour ſervir à la Diſtribution des Bois employés aux <lb/># Cazernes précédentes. # 56 <lb/>Devis pour la Conſtruction d’un Magaſin à Poudre très-ſolide, <lb/># de 10 toiſes de longueur ſur 4 de largeur. # 67 <lb/>Devis de la grande Citerne de Calais. # 75 <lb/></note> </div> <div xml:id="echoid-div738" type="section" level="1" n="234"> <head xml:id="echoid-head465" xml:space="preserve">Fin de la Table.</head> <pb file="0637" n="689"/> <pb file="0638" n="690"/> <pb file="0639" n="691"/> <pb file="0640" n="692"/> <pb file="0641" n="693"/> <handwritten/> <pb file="0642" n="694"/> </div> </text> </echo>