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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:0347ZVRW.xml</dcterms:identifier>
    <dcterms:creator identifier="GND:119477912">Bianconi, G. Ludovico</dcterms:creator>
    <dcterms:title xml:lang="it">Due lettere di fisica al signor marchese Scipione Maffei</dcterms:title>
    <dcterms:date xsi:type="dcterms:W3CDTF">1746</dcterms:date>
    <dcterms:language xsi:type="dcterms:ISO639-3">ita</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>
  </metadata>
  <text xml:lang="it" 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"/>
</div>
<div xml:id="echoid-div2" type="section" level="1" n="2">
<head xml:id="echoid-head1" xml:space="preserve">DUE</head>
<head xml:id="echoid-head2" xml:space="preserve"><emph style="red">LETTERE DI FISICA</emph></head>
<head xml:id="echoid-head3" style="it" xml:space="preserve">AL SIGNOR MARCHESE</head>
<head xml:id="echoid-head4" xml:space="preserve"><emph style="red">SCIPIONE MAFFEI</emph></head>
<head xml:id="echoid-head5" xml:space="preserve">CONDOTTIERE D’ARMIDELLA</head>
<head xml:id="echoid-head6" xml:space="preserve"><emph style="red">REPUBBLICA DI VENEZIA</emph></head>
<head xml:id="echoid-head7" xml:space="preserve">E Gentiluomo di Camera del</head>
<head xml:id="echoid-head8" xml:space="preserve"><emph style="red">RE DI SARDEGNA</emph></head>
<head xml:id="echoid-head9" style="it" xml:space="preserve">Scritte dal Signor</head>
<head xml:id="echoid-head10" xml:space="preserve"><emph style="red">GIANLODOVICO BIANCONI</emph></head>
<head xml:id="echoid-head11" xml:space="preserve">Conſigliere e primo Medico del</head>
<head xml:id="echoid-head12" xml:space="preserve"><emph style="red">LANGRAVIO DI DARMSTATT PRINGIPE</emph></head>
<head xml:id="echoid-head13" xml:space="preserve">E VESCOVO DI AUGUSTA.</head>
  <figure>
    <image file="0005-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/0347ZVRW/figures/0005-01"/>
  </figure>
</div>
<div xml:id="echoid-div3" type="section" level="1" n="3">
<head xml:id="echoid-head14" xml:space="preserve"><emph style="red">IN VENEZIA</emph></head>
<head xml:id="echoid-head15" xml:space="preserve">MDCCXLVI.</head>
<head xml:id="echoid-head16" xml:space="preserve"><emph style="red"><emph style="sc">Appresso</emph> <emph style="sc">Simone</emph> <emph style="sc">Occhi,</emph></emph></head>
<head xml:id="echoid-head17" style="it" xml:space="preserve">CONLICENZADE’SUPERIORI, E PRIVILEGIO.</head>
<pb file="0006" n="6"/>
<pb file="0007" n="7"/>
</div>
<div xml:id="echoid-div4" type="section" level="1" n="4">
<head xml:id="echoid-head18" xml:space="preserve">DELLE <lb/>CARAFFE DI VETRO</head>
<head xml:id="echoid-head19" xml:space="preserve">Che ſcoppiano al cadervi dentro di alcune <lb/>picciole materie,</head>
<head xml:id="echoid-head20" xml:space="preserve">E DI ALTRI VETRI CURIOSI</head>
<head xml:id="echoid-head21" xml:space="preserve">PRIMA LETTERA.</head>
<pb file="0008" n="8"/>
</div>
<div xml:id="echoid-div5" type="section" level="1" n="5">
<head xml:id="echoid-head22" style="it" xml:space="preserve">Correzione di errori di ſtampa.</head>
<note position="right" xml:space="preserve"> <lb/>Pag. # lin. <lb/>12 # 13 # intera <lb/>14 # 1 # obbiezioni <lb/>36 # 4 # fecene <lb/>43 # 4 # materia <lb/>46 # 4 # eſempio <lb/>47 # 17 # ſono <lb/> # 21 # altra <lb/>49 # 8 # gettanſi <lb/>61 # 13 # ſempre <lb/>65 # 18 # metallo <lb/>70 # 16 # far punto <lb/>71 # 7 # compimento a quanto <lb/>86 # 18 # detto <lb/>93 # 16 # appunto <lb/>98 # 6 # elaſticità <lb/>102 # 17 # acqua <lb/></note>
<pb o="I" file="0009" n="9"/>
</div>
<div xml:id="echoid-div6" type="section" level="1" n="6">
<head xml:id="echoid-head23" style="it" xml:space="preserve">SIGNOR MARCHESE.</head>
<p>
  <s xml:id="echoid-s1" xml:space="preserve">LA rara gentilezza e cor-<lb/>teſia colla quale il Sig. <lb/></s>
  <s xml:id="echoid-s2" xml:space="preserve">Marcheſe mio Signore mi <lb/>accolſe e ricevè, nel paſ-<lb/>ſare che per Verona io <lb/>feci, alloraquando veniva a quefta Sere-<lb/>niſſima Corte d’ Auguſta, reſtommi tal-<lb/>mente fiſſa nell’animo, che mai non fia <lb/>ch’io poſſa dimenticarmene, nè per lun-<lb/>ghezza di tempo, nè per gran tratto di
<pb o="II" file="0010" n="10"/>
paeſe che da lei mi divida. </s>
  <s xml:id="echoid-s3" xml:space="preserve">In prova <lb/>di queſta mia riſpettoſa gratitudine, e <lb/>della ſtima che far debbo della ſua in-<lb/>ſigne ſcienza e vaſta letteratura, ho de-<lb/>terminato eſporle in iſcritto alcune Oſ-<lb/>ſervazioni e rifleſſioni fiſiche, le qualì <lb/>lio fatte ſopra quelle groſſe Caraffe di <lb/>Vetro@che al gettarvi dentro di un pic-<lb/>coliſſimo @rammento di Criſtallo o di Sel-<lb/>ce, ſcoppiano in quel momento o qual-<lb/>che piccol tempo dopo. </s>
  <s xml:id="echoid-s4" xml:space="preserve">e rotte cado-<lb/>no@in pezzi; </s>
  <s xml:id="echoid-s5" xml:space="preserve">come pure qualche coſuc-<lb/>cia ſopra quelle palle di Vetro vuote ed <lb/>ermeticamente chiuſe continenti un qual-<lb/>che corpo ſtraniero, le quali rompendo-<lb/>ſi fanno uno ſtrepito grandiſſimo non al-<lb/>trimenti che ſe ſcoppiaſſe un fucile od <lb/>una ben carica piſtola. </s>
  <s xml:id="echoid-s6" xml:space="preserve">Ho creduto anco-<lb/>ra che il far queſto ſia un mio puro <lb/>ed eſpreſſo dovere, prima perchè ſe ben <lb/>le torna a mente ricorderaſſi, che facen-
<pb o="III" file="0011" n="11"/>
domi anch’ ella veder tali vetri, a lei <lb/>donati in Torino da S. </s>
  <s xml:id="echoid-s7" xml:space="preserve">A. </s>
  <s xml:id="echoid-s8" xml:space="preserve">R. </s>
  <s xml:id="echoid-s9" xml:space="preserve">il Duca <lb/>di Savoja, giovane Principe di ammira-<lb/>bile ingegno, e facendoſi ſopra codeſte <lb/>Caraffe un lungo diſcorſo, io in certa <lb/>maniera le promiſi di farle ſapere quel-<lb/>lo che io ne penſava; </s>
  <s xml:id="echoid-s10" xml:space="preserve">ſecondo perchè <lb/>riſpetto alle palle delle quali farò pa-<lb/>rola nell’ ultimo, io le vidi la prima vol-<lb/>ta da lei, ed imparai a conoſcerle in <lb/>ſua caſa non meno d’ inſigni antichità <lb/>e di ſcelti libri fornita, che di curioſiſ-<lb/>ſime, e ſtrane produzioni della natura: <lb/></s>
  <s xml:id="echoid-s11" xml:space="preserve">laſciando per ora da parte l’ampia e <lb/>prezioſa raccolta sì di Libri che di ra-<lb/>rità naturali, fatta dal ſuo fido Acate il <lb/>Sig. </s>
  <s xml:id="echoid-s12" xml:space="preserve">Franceſco Seguier Gentiluomo Fran-<lb/>cefe, che da quatordici anni ha la ſorte di <lb/>conviver ſeco, e che con due bell’opere <lb/>botanicheſi è già reſo celebre. </s>
  <s xml:id="echoid-s13" xml:space="preserve">La prego ad <lb/>iſcuſarmi ſe prima d’ora non ho ſoddisfatto
<pb o="IV" file="0012" n="12"/>
a queſto mio penſiere, imperciocchè ol-<lb/>tre a varie facende che mi hanno non <lb/>poco e giuſtamente occupato, la ſplen-<lb/>didezza anch’eſſa di queſta Corte in cui <lb/>ho la fortuna di vivere, e la novità del-<lb/>le coſe le quali agli occhi miei, all’ <lb/>Italia ſola finora avvezzi, ſi preſentaro-<lb/>no tutte in una volta, hanno fatto tale <lb/>ſpecie nell’ animo mio, che da queſto <lb/>buon volere lo hanno quaſi a forza di-<lb/>ſtolto, ed Auguſta ha prodotto in me <lb/>quello che già produſſe nell’animo dell’ <lb/>immenſo noſtro Arioſto la nuova abita-<lb/>zione che intrapreſe ſu le rive della <lb/>ſtrepitoſa confluente della Turrita e del <lb/>Serchio; </s>
  <s xml:id="echoid-s14" xml:space="preserve">potendo dire anch’io,</s>
</p>
<p style="it">
  <s xml:id="echoid-s15" xml:space="preserve">La novità del loco è ſtata tanta,</s>
</p>
<p style="it">
  <s xml:id="echoid-s16" xml:space="preserve">Che ho fatto come Augel, che muta gabbia,</s>
</p>
<p style="it">
  <s xml:id="echoid-s17" xml:space="preserve">Che molti giorni reſta, che non canta.</s>
  <s xml:id="echoid-s18" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s19" xml:space="preserve">Tutto ripromettendomi adunque dalla <lb/>ſua bontà, della quale non lice a chi
<pb o="V" file="0013" n="13"/>
che ſia ſenza offenderla dubitare, inco-<lb/>mincierò ſenz’ altro a parlare delle noſtre <lb/>Caraffe, e le dirò prima, che da alcu-<lb/>ne parole le quali leggonſi nel fine del <lb/>Trattato _delle Affezioni de’Corpi_ del Signor <lb/>di Hamel, celebre riſtoratore della Fiſi-<lb/>ca, da quei Dottori _Acuti, Irrefragabili,_ <lb/>_Riſſoluti, Sottili,_ ed altri che per riſpetto <lb/>non nomino, colla autorità d’Ariſtote-<lb/>le il più delle volte ſtorpiato e non <lb/>inteſo, rovinata intieramente e diſtrut-<lb/>ta; </s>
  <s xml:id="echoid-s20" xml:space="preserve">da alcune parole ſue dico ſcorgeſi, <lb/>che egli ſapea qualche coſa, o di que-<lb/>ſto, o di conſimil fenomeno. </s>
  <s xml:id="echoid-s21" xml:space="preserve">Eccole <lb/>quello ch’ei dice “Quod autem contex-<lb/>tus partium, figura, &amp; </s>
  <s xml:id="echoid-s22" xml:space="preserve">tenſio praeci-<lb/>puae fint hujus phaenomeni cauſſae, <lb/>hinc etiam licet conijcere, quod Pilae <lb/>conflatae ex vitro candido (quod viridi <lb/>fragilius eſt &amp; </s>
  <s xml:id="echoid-s23" xml:space="preserve">poris magis pervium, <lb/>nec ex fornace extractum in arca ſu-
<pb o="VI" file="0014" n="14"/>
periori, ut alia vitra; </s>
  <s xml:id="echoid-s24" xml:space="preserve">reponitur) fa-<lb/>cile in partes diſſiliunt ubi ſcalpelli, <lb/>vel ſtyli apice celeri, ac reciproco mo-<lb/>tu perfricantur; </s>
  <s xml:id="echoid-s25" xml:space="preserve">nam partes praeſertim <lb/>interiores pilae, aut vitri concavi hoc <lb/>celerimotu luxatae, non valent amplius <lb/>exteriores continere. </s>
  <s xml:id="echoid-s26" xml:space="preserve">Et quidem mihi, <lb/>anno proxime elapſo oſtendit Domi-<lb/>nus Boyle vitrum ſolidum chriſtallo pu-<lb/>riſſimae ſimile, quod levi motu affri-<lb/>ctum in varias diſſiluir partes.</s>
  <s xml:id="echoid-s27" xml:space="preserve">“ Puoſſi <lb/>parlare, a quel che parmi, più chiara-<lb/>mente?</s>
  <s xml:id="echoid-s28" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s29" xml:space="preserve">S’inferiſce da queſto, che il Boyle <lb/>anch’eſſo ſapea qualche coſa di ſomi-<lb/>gliantc; </s>
  <s xml:id="echoid-s30" xml:space="preserve">ed in prova di queſto molte co-<lb/>ſe troverannoſi nel di lui TrattatO _della_ <lb/>_aſſoluta quiete de’Corpi_ le quali conferme-<lb/>ranno il ſoſpetto mio. </s>
  <s xml:id="echoid-s31" xml:space="preserve">Tuttavolta qua-<lb/>lunque ſiaſi la coſa, il fatto è, che di <lb/>queſta fiſica curioſità eraſene ſul princi-
<pb o="VII" file="0015" n="15"/>
pio di queſto ſecolo perduta intieramen-<lb/>te la rimembranza, alloraquando l’anno <lb/>1716 il Sig. </s>
  <s xml:id="echoid-s32" xml:space="preserve">Canonico Gian-Giacomo <lb/>Amadei Bologneſe accidentalmente le <lb/>ſcoperſe il primo un giorno che trova-<lb/>vaſi alla fornace dei vetri, dove ſo-<lb/>leva ſpeſſiſſimo andare, perchè come aſ-<lb/>ſai amante della fiſica, capiva che in <lb/>quel luogo più che in altri, molti ed <lb/>aſſai vaghi ſcherzi della natura quotidia-<lb/>namente ſi preſentano agli occhi degli <lb/>ſpettatori, che traſcurati poi vengono, <lb/>o per la troppa frequenza con cui ſi <lb/>laſcian vedere, o per quella indolenza <lb/>che in ſimili coſe aver ſogliono coloro, <lb/>la mente dei quali non è ſtata dalla ſi. <lb/></s>
  <s xml:id="echoid-s33" xml:space="preserve">loſofia, per così dire, ſvegliata e meſ-<lb/>ſa in curioſità. </s>
  <s xml:id="echoid-s34" xml:space="preserve">Dico, che accidental-<lb/>mente ei le ſcoperſe, perchè ſenza pen-<lb/>ſarvi, vide che per eſſervi caduti dentro <lb/>alcuni frammentucci di vetro, ſcoppiò
<pb o="VIII" file="0016" n="16"/>
una ben groſſa e robuſta Caraffa, dall’ <lb/>artefice gettata ancor rovente tra i ve-<lb/>tri da novamente fonderſi, come far ſo-<lb/>gliono di quei lavori, i quali incommin-<lb/>ciati, conoſceſi che non potranno riu-<lb/>ſcire a perfezione. </s>
  <s xml:id="echoid-s35" xml:space="preserve">Reſtò ſorpreſo al ve-<lb/>dere queſta ſtravagante novità, provolla <lb/>per aſſcurarſene in altre Caraffe ſimili <lb/>o quaſi ſimili alle noſtre, che là pure <lb/>tra i riſiuti ſi ſtavano, e domandandone <lb/>con impazienza ai vetrai la cagione, ſe <lb/>pur la ſapeano, null’altro vedevaſi da <lb/>coſtoro riſpondere, ſe non che maravi-<lb/>gliavanſi e quaſi ridevano nel vederlo <lb/>anſioſo di ſapere una coſa, che eſſi co-<lb/>me inutile e puerile avevano ſempre <lb/>mai riguardata.</s>
  <s xml:id="echoid-s36" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s37" xml:space="preserve">Fatteſi adunque fabbricar molte di que-<lb/>ſte Caraffe e ſeco portatele, moſtrolle <lb/>fra gli altri Filoſofi della noſtra Bolo-<lb/>gneſc Accademia, al Sig. </s>
  <s xml:id="echoid-s38" xml:space="preserve">Generale Con-
<pb o="IX" file="0017" n="17"/>
te Luigi-Ferdinando Marſilli di celebre <lb/>memoria, a cui pure giunſero nove in-<lb/>tieramente, e che con gran piacere e <lb/>diligenza le conſiderò. </s>
  <s xml:id="echoid-s39" xml:space="preserve">Dopo la novità <lb/>della coſa e dopo varj diſcorſi, come <lb/>il più delle volte anche a danno delle <lb/>ſcienze accader ſuole, ſi poſero in ſilen-<lb/>zio le Caraffe e reſtarono quaſi neglet-<lb/>te nella dimenticanza fino all’anno, ſe <lb/>non erro, 1735. </s>
  <s xml:id="echoid-s40" xml:space="preserve">alloraquando il Sig. </s>
  <s xml:id="echoid-s41" xml:space="preserve">Pao-<lb/>lo-Battiſta Balbi, che come diligentiſſi-<lb/>mo cuſtode, anzi cercatore della natura <lb/>non le avea forſe come alcun’altro ob-<lb/>bliate, parlando all’ Accademia dell’In-<lb/>ſtituto di que’ vetri che ſpontaneamen-<lb/>te ſi rompono, nominò queſte ancora, <lb/>quaſi accortamente ad eſſa ricordandole <lb/>acciocchè non le perdeſſe di viſta. </s>
  <s xml:id="echoid-s42" xml:space="preserve">Da <lb/>allora fino all’anno cred’io 1740 ſe <lb/>ne andò da ognuno parlando, e da va-<lb/>rj ſe ne ruppero moltiſſime, quantunque
<pb o="X" file="0018" n="18"/>
neſſuno aveſſe ancora intrapreſo partico-<lb/>larmente d’eſaminarle, come ſe per la <lb/>bellezza e rarità della coſa i fiſici fat-<lb/>ti ſoverchiamente civili, quaſi ſi cedeſſe-<lb/>ro l’un l’altro la preferenza. </s>
  <s xml:id="echoid-s43" xml:space="preserve">Da Bolo-<lb/>gna io credo che lo imparaſſero allora <lb/>molte Città dell’Italia, e fuori d’ Italia <lb/>ancora, anzi di alcune potrei io ſicura-<lb/>mente indicare la ſtrada e il mezzo per <lb/>cui lo ſeppero, ſe non temeſſi che co-<lb/>deſta quaſi Genealogia foſſe per eſſere <lb/>inutile e ſtucchevole. </s>
  <s xml:id="echoid-s44" xml:space="preserve">Queſto ſia detto <lb/>primieramente per rendere alla patria mia <lb/>quella giuſtizia che debbole, e per la <lb/>quale, ſe non puoſſi chiamar la inven-<lb/>trice di queſte caraffe, potrà dirſi alme-<lb/>no la prima rinovatrice; </s>
  <s xml:id="echoid-s45" xml:space="preserve">e ſecondaria-<lb/>mente per ſoddisfare a quell’ obbligo il <lb/>quale pare che oggigiorno corra ad ogni <lb/>Scrittore, di dover rendere piena ragione <lb/>di quanto può appartenere alla materia ch
<pb o="XI" file="0019" n="19"/>
egli prende a trattare, e di porvi avantiun <lb/>proemio iſtorico o cronologico, ſiane pure <lb/>quanto vuolſi oſcura o favoloſa la origine.</s>
  <s xml:id="echoid-s46" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s47" xml:space="preserve">Le Caraffe adunque, benchè ella mol-<lb/>to meglio di me lo ſappia, hanno la qui <lb/>anneſſa figura _(Fig. </s>
  <s xml:id="echoid-s48" xml:space="preserve">I.)</s>
  <s xml:id="echoid-s49" xml:space="preserve">_ e poſſono eſſere <lb/>talora più talora men grandi, come ſi <lb/>vuole. </s>
  <s xml:id="echoid-s50" xml:space="preserve">Da quello che ſopra ſi è detto <lb/>comprendeſi, che ſempliciſſimamente ſi <lb/>fabbricano, e nella maniera con cui faſ-<lb/>ſi qualunque altro benche<unsure/> rozzo lavoro <lb/>di vetro. </s>
  <s xml:id="echoid-s51" xml:space="preserve">La ſola differenza che tra <lb/>eſſe e gli altri paſſa è, che ſiccome <lb/>queſti appena finiti ſi mettono dal Ve-<lb/>trajo nella ſtufa riſcaldata e ſovrappoſta <lb/>alla medeſima fornace, acciocchè per <lb/>gradi paſſino dal calore grandiſſimo del-<lb/>le fiamme all’ aria naturalmente tempe-<lb/>rata; </s>
  <s xml:id="echoid-s52" xml:space="preserve">così quelle appena fatte ſi eſpon-<lb/>gono all’ aria libera, e ſenza altra dili-<lb/>genza ſi allontanano dal fuoco. </s>
  <s xml:id="echoid-s53" xml:space="preserve">Due
<pb o="XII" file="0020" n="20"/>
cauzioni ſolamente ſono afſai neceſſarie, <lb/>perchè naſcano a dovere; </s>
  <s xml:id="echoid-s54" xml:space="preserve">l’una che nel <lb/>fondo ſieno aſſai groſſe, e quanto più <lb/>lo ſaranno ſarà meglio, non eſſendovi <lb/>limite alcuno; </s>
  <s xml:id="echoid-s55" xml:space="preserve">l’ altra che nell’eſpor-<lb/>le all’ aria ſi avverta, che queſta non <lb/>ſia troppo fredda, perchè non ſalvando-<lb/>ſene che poche nell’altra maniera, in <lb/>queſta poi ſenza dubbio alcuno non ſe <lb/>ne potrebbe ſalvare nè pure una. </s>
  <s xml:id="echoid-s56" xml:space="preserve">Queſt <lb/>ultima condiziono io credo fia ſtata la <lb/>ſola cauſa, per la quale ho tanto ſten-<lb/>tato per averne alcuna ìntera dalle for-<lb/>naci qui di Germania, perchè a diſpetto <lb/>di qualunque diligenza, l’ aria che qui <lb/>ſempre più toſto freſca che no ſpira, me <lb/>le faceva tutte andare in pezzi prima di <lb/>raffreddarſi. </s>
  <s xml:id="echoid-s57" xml:space="preserve">Qualunque per altro fiaſi <lb/>il Vetro e qualunque ſiaſi la fornace, l’ <lb/>eſperienza è ſempre preſſo a poco la <lb/>ſteſſa, ed è quaſi inutile il fare ſu que-
<pb o="XIII" file="0021" n="21"/>
ſto alcuna diligenza, perchè il fenome-<lb/>no come fino ad ora ſi è viſto, è uni-<lb/>verſale a tutti i vetri, ed in qualunque <lb/>luogo fabbricati. </s>
  <s xml:id="echoid-s58" xml:space="preserve">Dico preſſo a poco la <lb/>ſteſſa, perchè egli è indubitabile che rie-<lb/>ſcono più fragili le Caraffe fatte di ve-<lb/>tro impuro e crudo, che quelle fatte di <lb/>vetro fino e ben cotto. </s>
  <s xml:id="echoid-s59" xml:space="preserve">Eccole in poche <lb/>parole come le Caraffe ſi fanno: </s>
  <s xml:id="echoid-s60" xml:space="preserve">paſſiſi <lb/>ora a dire come elle ſi rompano.</s>
  <s xml:id="echoid-s61" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s62" xml:space="preserve">Nel far queſto io p@nſo di prima eſpor-<lb/>le non dirò un ſiſtema, ma un penſie-<lb/>re che io ho, fondato parte ſu le mie, <lb/>parte fu le altrui rifleſſioni, e quindi <lb/>naſcendo come Corollarj da Propoſizio-<lb/>ne le eſperienze da me e da varj altri <lb/>fatte, dare con queſto metodo più aria <lb/>di veriſimiglianza che ſia poſſibile al mio <lb/>diſcorſo. </s>
  <s xml:id="echoid-s63" xml:space="preserve">Ella non credeſſe già, che m’ <lb/>impuntaſſi poi a difenderlo _unguibus &amp;_</s>
  <s xml:id="echoid-s64" xml:space="preserve"> <lb/>_roſtro_, e voleſſi ſalvarlo malgrado tutte
<pb o="XIV" file="0022" n="22"/>
le più giuſte obiezioni, e come dice il <lb/>grazioſo Moliere, ſoſtentarlo ſino all’ ul-<lb/>tima goccia del mio inchioſtro. </s>
  <s xml:id="echoid-s65" xml:space="preserve">Trop-<lb/>po conoſco per non impegnarmici, le dif-<lb/>ficoltà che incontriamo quando voglia-<lb/>mo ſcoprire le cauſe della natura.</s>
  <s xml:id="echoid-s66" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s67" xml:space="preserve">Io ſuppongo adunque, che ogni vetro <lb/>groſſo il quale abbia conveſità da una <lb/>parte e concavità qualunque ſiaſi dall’ <lb/>altra, e che dalla fornace entro cui è <lb/>ſtato fabbricato paſſi all aria libera ſen-<lb/>za eſſere ſtato il dovuto tempo nella <lb/>Stufa a cuocerſi, ſe non va in pezzi co-<lb/>me il più delle volte ſuol fare, ſuppon-<lb/>go dico, che abbia talmente diſpoſte le <lb/>piccole ſue parti componenti, che ſi ſo-<lb/>ſtentino reciprocamente sì, ma che lo <lb/>facciano in tal maniera, che ſe una ſo-<lb/>la di queſte nella parte più debole, cioè <lb/>come moſtrerò più avanti nella inter-<lb/>na, movaſi dal luogo ſuo, tutte le
<pb o="XV" file="0023" n="23"/>
altre anch’ eſſe debbano per la loro vi-<lb/>cinanza diſunirſi e moverſi, e così fa-<lb/>re che intieramente quel compoſto rovi-<lb/>ni per così dire e cada, come in gran-<lb/>de nelle volte delle Stanze o negli Ar-<lb/>chi vediamo giornalmente accadere. </s>
  <s xml:id="echoid-s68" xml:space="preserve">Io <lb/>quì in prova di queſto mio penſiere, <lb/>all’ uſanza di quei filoſofi che una <lb/>volta davano fino in iſtampa la figura <lb/>e la grandezza delle immaginate parti-<lb/>celle componenti la loro vorticoſa ma-<lb/>teria non altrimenti che ſe vedute le <lb/>aveſſero, potrei farle un lungo nojoſo <lb/>diſcorſo ſopra la ſtruttura del vetro e dei <lb/>ſuoi componenti, e moſtrarle forſe anco <lb/>con Euclide alla mano, la diſavvantag-<lb/>gioſa unione delle ſue particole. </s>
  <s xml:id="echoid-s69" xml:space="preserve">Ma mi <lb/>perdoni Sig. </s>
  <s xml:id="echoid-s70" xml:space="preserve">Marcheſe, ſe pregola a diſ-<lb/>penſarmene, perchè ingenuamente le con-<lb/>feſſo che non avrò mai il coraggio di <lb/>aſſerir per vera alcuna di quelle coſe,
<pb o="XVI" file="0024" n="24"/>
che negatami poi non ſaprei come po-<lb/>ter provare. </s>
  <s xml:id="echoid-s71" xml:space="preserve">Solo dirò , che l’ ineguale <lb/>raffreddamento delle parti eſterne ed in-<lb/>terne della Caraffa quando diſcoſtaſi dal-<lb/>la fornace, e per il quale le parti eſter-<lb/>ne cominciano per ragione dell’ aria che <lb/>le circonda e tocca, a coſtringerſi e raſ-<lb/>freddarſi, nel tempo che le interne rare-<lb/>fatte e roventi ſeguono ancora a mover-<lb/>ſi con moto rapidiſſimo, pare moſtrar <lb/>ſufficientemente, che la coſa poſſa eſſe-<lb/>re qual ſopra dicevale, cioè che le par-<lb/>ti debbano ſtare fra di loro in una ten-<lb/>fione molto inuguale, e in conſeguenza <lb/>in equilibrio sì, ma in un equilibrio de-<lb/>boliſſimo ed aſſai facile a toglierſi. </s>
  <s xml:id="echoid-s72" xml:space="preserve">L’ <lb/>oculare inſpezione dei frammenti anch’ <lb/>eſſi della Caraffa potrà favorire in qual-<lb/>che maniera codeſto penſamento. </s>
  <s xml:id="echoid-s73" xml:space="preserve">Imper-<lb/>ciocchè ella li vedrà d’ ordmario nella <lb/>ſuperficie della Sezione dalla parte che
<pb o="XVII" file="0025" n="25"/>
riguarda l’ eſterno aſſai liſ@i e politi, co-<lb/>me ſe il vetro qui foſſe compatto ed <lb/>in ſeſteſſo riſtretto, e vedralli aſpri men-<lb/>lucidi e quaſi increſpati dalla parte che <lb/>riguarda la ſuperficie interna, quaſichè <lb/>ivi foſſe rarefatto e di teſtura più larga.</s>
  <s xml:id="echoid-s74" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s75" xml:space="preserve">Nel leggere ch’ ella avrà fatto quello <lb/>ch’ io credo della interna ſtruttura del-<lb/>le Caraffe, le ſarà venuto in mente di <lb/>aver viſta coſa in parte ſimile in quel-<lb/>la elegante diſſertazione latina ſtampata <lb/>l’anno ſcorſo in Padova da un’anonimo <lb/>Autore, il quale non è che un dotto <lb/>e conoſciuto Sacerdote della Compagnia <lb/>di Gesù. </s>
  <s xml:id="echoid-s76" xml:space="preserve">Imperciocchè ivi ella avrà tro-<lb/>vato un ſimil penſiere, ma molto più <lb/>diffuſamente e chiaramente ſpiegato, e <lb/>che io ho voluto ſeguitare ed abbraccia-<lb/>re, non già per quella ſtima che mi pro-<lb/>teſto di avere per lo Scrittore, ma ſo-<lb/>lamente perchè parevami troppo unifor-
<pb o="XVIII" file="0026" n="26"/>
me allo agire della natura, e ſecondo <lb/>le Leggi inviolabili della Fiſica.</s>
  <s xml:id="echoid-s77" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s78" xml:space="preserve">Ciò determinato adunque ne viene per <lb/>conſeguenza, che perchè rompaſi la Ca-<lb/>raffa, egli è neceſſario che dal corpicci-<lb/>uolo il qual’ entro le cade, ſia in qual-<lb/>che modo sfregiata, e per così dire nel-<lb/>la ſua parte interna e più fragile inco-<lb/>minciata a rompere. </s>
  <s xml:id="echoid-s79" xml:space="preserve">E ſiccome ogni cor-<lb/>po quando non aveſſe un grandiſſimo <lb/>momento, o a cagione della ſua gran-<lb/>dezza, o a cagione di una ſtraordinaria <lb/>velocità non è capace o valevole a sfre-<lb/>giare e rompere la ſuperficie dei vetri, <lb/>così ne ſegue che non a tutti è dato il <lb/>poter rompere le noſtre Caraffe, come <lb/>l’ eſperienza ci inſegna. </s>
  <s xml:id="echoid-s80" xml:space="preserve">Le romperanno <lb/>adunque coſtantemente, benchè in pic-<lb/>coliſſima mole, que’ corpi che per ſe-<lb/>ſteſſi ſono atti a tagliare il vetro; </s>
  <s xml:id="echoid-s81" xml:space="preserve">ed <lb/>eccole per qual cauſa nè i metalli,
<pb o="XIX" file="0027" n="27"/>
quando non ſieno di mole conſiderabile <lb/>e non abbiano angoli taglienti e ben <lb/>duri, nè l’ avorio, nè i legni ſogliono <lb/>rompere le Caraffe ſe ad eſſe ſi gettano <lb/>dentro. </s>
  <s xml:id="echoid-s82" xml:space="preserve">Eccole poi al contrario perchè <lb/>le ſcaglie di Criſtallo, di Pietra focaja <lb/>di Diaſpro, d’ Agata, le Pietre prezioſe, <lb/>particolarmente ſe anno molti angoli e <lb/>punte, le rompono ſempre, eſſendo cor-<lb/>pi che di natura loro a cagione della <lb/>durezza po@@ono @@gnare, anzi ſegnano <lb/>e sfregiano la ſuperficie dei vetri. </s>
  <s xml:id="echoid-s83" xml:space="preserve">Non <lb/>dovrebbe ora recar più maraviglia, ſe il <lb/>Diamante meglio di ogni altro corpo e <lb/>più ſpeditamente le rompe, quantunque <lb/>ſia ſolamente del peſo di un mezzo gra-<lb/>no, e ſino d’ un’ ottavo, ſapendo noi che <lb/>nella natura non c’ è corpo che più a-<lb/>gevolmente di queſto sfregj i vetri anche <lb/>col ſolo leggeriſſimo toccarli.</s>
  <s xml:id="echoid-s84" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s85" xml:space="preserve">Se la coſa adunque è così, venir ne
<pb o="XX" file="0028" n="28"/>
dee di giuſta conſeguenza, che per man-<lb/>dare in pezzi le Caraffe non ſarà neceſ-<lb/>ſario il laſciare ad eſſe cader dentro il <lb/>corpicciuolo angoloſo, ma che baſterà <lb/>metterglielo nel fondo con qualche iſtru-<lb/>mento che glielo porti, e far sì che con <lb/>un poco di forza lo tocchi, tanto che <lb/>ne reſti in qualche modo sfregiata e pun-<lb/>ta per così dire la ſuperficie. </s>
  <s xml:id="echoid-s86" xml:space="preserve">Si doman-<lb/>derà, ſe queſta forza poi debba eſſer no-<lb/>tabile o no, al che ri@pond@rò, che ſem-<lb/>pre è aſſai leggera, ma che è maggiore <lb/>o minore ſecondo la durezza, la ſtrut-<lb/>tura, e la materia dei corpicciuoli più <lb/>o men favorevole a sfregiare il vetro; <lb/></s>
  <s xml:id="echoid-s87" xml:space="preserve">di tal maniera che probabilmente potreb-<lb/>be ſtabilirſi queſta legge, che date alcu-<lb/>ne piccole ſcheggie di figura e grandez-<lb/>za coſtante di que’ corpi che ſopra ab-<lb/>biamo detto eſſere atti a rompere una <lb/>Caraffa, la forza che dovraſſi con eſſe
<pb o="XXI" file="0029" n="29"/>
farle al fondo acciocchè fi rompa, ſta-<lb/>rà nella inverſa della loro differente na-<lb/>turale durezza. </s>
  <s xml:id="echoid-s88" xml:space="preserve">Da queſto adunque ne <lb/>viene, che l’ atto della caduta ſopra <lb/>del quale hanno fatto tante diligenze e <lb/>meditazioni tutti quelli che finora hanno <lb/>parlato di queſto fenomeno, può dirſi <lb/>che ſia inutile e che non influiſca nella <lb/>rottura del vetro, ſe non per quel pic-<lb/>coliſſimo momento che comunica al cor-<lb/>picciuolo, per cagione dell’ affrettarſi che <lb/>fanno i gravi nel cadere.</s>
  <s xml:id="echoid-s89" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s90" xml:space="preserve">Io credo d’ aver già ſvelato tutto l’ <lb/>arcano e di avere in mano il filo di Ari-<lb/>anna che ſicuramente diſtinguerà le fal-<lb/>ſe dalle vere ſtrade, onde poterſi inter-<lb/>nare in queſto fiſico laberinto; </s>
  <s xml:id="echoid-s91" xml:space="preserve">e ſe lo-<lb/>devole è ſempre la verità, io potrò di-<lb/>re che fui uno dei primi, il quale pen-<lb/>ſando a queſto intrigatiſſimo eſperimen-<lb/>to, ſoſpettai eſſerci neceſſario lo sfregio,
<pb o="XXII" file="0030" n="30"/>
e che ſenza di lui inutil foſſe il gettar <lb/>dentro alle Caraffe con quanta forza vo-<lb/>levaſi i corpi. </s>
  <s xml:id="echoid-s92" xml:space="preserve">Comunicai queſto ſoſpet-<lb/>to mio fin da quando trovavami in Bo-<lb/>logna alla ſcelta fiſica radunanza che due <lb/>volte la ſettimana tienſi appreſſo la dot-<lb/>tiſſima Signora Laura Baſſi-Verati, il no-<lb/>me della quale baſta da sè per non aver <lb/>biſogno d’aggiugnerli altra lode. </s>
  <s xml:id="echoid-s93" xml:space="preserve">Qui el-<lb/>la ci avrebbe veduti in ſei o ſette aſſiſi <lb/>tutti d’intorno ad una tavola coperta d’ <lb/>ogn’intorno di Caraffe parte rotte e par-<lb/>te da romperſi, giacchè ci eramo delibe-<lb/>rati a forza di eſperimenti di voler cer-<lb/>care e trovare ancora ſe pur potevaſi, <lb/>dove ed in che conſiſteſſe codeſto miſte-<lb/>ro. </s>
  <s xml:id="echoid-s94" xml:space="preserve">Determinoſſi di farne allor’ allora la <lb/>prova, e così ſciorre ſul fatto la quiſtio-<lb/>ne. </s>
  <s xml:id="echoid-s95" xml:space="preserve">Dopo varj metodi che ſi propoſero, <lb/>ci appigliammo ſinalmente a quello che <lb/>parve il più agevole d’ ogni altro, cioè
<pb o="XXIII" file="0031" n="31"/>
prendemmo uno di que’diamanti incaſtra-<lb/>ti nella eſtremità di una ſottile aſta di <lb/>ferro, dei quali ſoglionſi ſervire i vetraj <lb/>per tagliare le laſtre di vetro, o di cri-<lb/>ſtallo, e queſto deſtramente pel collo nel-<lb/>la Caraffa introdotto, lo portammo leg-<lb/>geriſſimamente a toccare il fondo. </s>
  <s xml:id="echoid-s96" xml:space="preserve">Non <lb/>ebbelo appena toccato, che la Caraffa non <lb/>altrimenti che ſe le ſi foſſe laſciato ca-<lb/>der dentro una conſiderabile ſcaglia di ſel-<lb/>ce o di criſtall@, d’ogn’intorno in mol-<lb/>tiſſimi pezzi ſcoppiò e con gran violen-<lb/>za ſi ruppe. </s>
  <s xml:id="echoid-s97" xml:space="preserve">Replicoſſi con attenzione l’ <lb/>eſperienza, e non ſolamente provoſſi col <lb/>diamante, ma altresì colla pietra focaja, <lb/>col vetro, e con altri corpi che nel ſo-<lb/>lito modo dentro delle altre Caraffe s’in-<lb/>troduſſero, ed ogniuno colle proprie ma-<lb/>ni ſi aſſicurò, che l’ effetto riuſciva co-<lb/>ſtantemente e a maraviglia, e che la pic-<lb/>cola forza colla quale dovevaſi toccare
<pb o="XXIV" file="0032" n="32"/>
il fondo, era ſenſibilmente minore qual-<lb/>ora toccavaſi col diamante che quando <lb/>toccavaſi colla pietra focaja, maggiore <lb/>quando toccavaſi col vetro, e così di ma-<lb/>no in mano.</s>
  <s xml:id="echoid-s98" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s99" xml:space="preserve">Dal fin qui detto ne viene, che o-<lb/>gniuno da ſe medeſimo potrà indovinare <lb/>come corollarj quaſi tutte le conſeguen-<lb/>ze di tanti eſperimenti fatti, e forſe an-<lb/>che da farſi intorno a queſti vetri. </s>
  <s xml:id="echoid-s100" xml:space="preserve">In <lb/>prova di che piaccial@ m@@@ confiderar-<lb/>ne alcuni che come i più inſigni quì ſot-<lb/>to per ordine le riſerirò. </s>
  <s xml:id="echoid-s101" xml:space="preserve">Una parte di <lb/>queſti è ſtata tentata dal Sign. </s>
  <s xml:id="echoid-s102" xml:space="preserve">Tomma-<lb/>ſo Laghi Pubblico Profeſſore di Medici-<lb/>na nella noſtra Univerſità di Bologna, <lb/>il quale dottamente e da valentuomo ha <lb/>molto cercato ſu queſto ſcherzo della na-<lb/>tura. </s>
  <s xml:id="echoid-s103" xml:space="preserve">Un’altra io l’ ho preſa dalla ſopra-<lb/>nominata diſſertazione di Padova, in cui <lb/>molti ve ne ſono diligentiſſimamente eſ-
<pb o="XXV" file="0033" n="33"/>
preſſi; </s>
  <s xml:id="echoid-s104" xml:space="preserve">e l’ altre tutte ſono ſtate fatte da <lb/>me o da alcuni amici miei in Italia, i <lb/>quali gentilmente mi hanno dell’ opera lo-<lb/>ro nell’ eſeguirle favorito, giacchè la mia <lb/>dimora quì in Germania togliemi molte <lb/>di quelle comodità che per tali prove ſon <lb/>neceſſarie.</s>
  <s xml:id="echoid-s105" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s106" xml:space="preserve">Per andare adunque con qualche me-<lb/>todo le dirò primieramente, che ſoſpet-<lb/>tò ſul principio taluno e ſoſpettò con <lb/>ragione, che l’ aria, o rinchiuſa in for-<lb/>ma di bolle nelle pareti della Caraffa, <lb/>o quella dell’ atmosfera da cui ſon cir-<lb/>condate e riempite, poteſſe avere qual-<lb/>che parte in queſto fenomeno, laonde <lb/>tentarono una lunga faſtidioſa ſerie di ri-<lb/>cerche nella Macchina pneumatica. </s>
  <s xml:id="echoid-s107" xml:space="preserve">Ma <lb/>ſiccome probabilmente, anzi giuſta quel-<lb/>lo che ſopra le ò eſpoſto, chiaramente ſi <lb/>vede che l’ aria in neſſuna maniera vi ha <lb/>parte, così queſte debbono romperſi egual-
<pb o="XXVI" file="0034" n="34"/>
mente nel vuoto che nel pieno, nè pa-<lb/>tiranno altro cangiamento, ſe non quel-<lb/>lo il quale è effetto dell’ impreſſione e-<lb/>ſterna che ſoffrir debbono tutti i corpi da <lb/>un fluido altiſſimo che d’ ogni parte li <lb/>circonda e preme. </s>
  <s xml:id="echoid-s108" xml:space="preserve">Nelle Caraffe adun-<lb/>que che ſi ruppero nel recipiente della <lb/>macchina pneumatica, nel qual caſo quel <lb/>poco d’ aria che ſnervata, per così dire, <lb/>e floſcia vi reſtava, era egualmente ra-<lb/>refatto dentro che fuori della Caraffa, <lb/>non vedevaſi alcun cangiamento nel fe-<lb/>nomeno, ſuccedendo queſto tal quale nel-<lb/>l’ aria aperta. </s>
  <s xml:id="echoid-s109" xml:space="preserve">Nella ſuddetta diſſertazio-<lb/>ne ella avrà vedute molte eſperienze che <lb/>le confermeranno l’ aſſerzion mia, ne vi <lb/>troverà altre anomalie, che quelle le qua-<lb/>li ſuccedono alla giornata anche nel pie-<lb/>no. </s>
  <s xml:id="echoid-s110" xml:space="preserve">Il Signor Laghi votò di aria colla <lb/>macchina una Caraffa, e per mezzo di <lb/>uno aſſai ſemplice artificio fecele cader
<pb o="XXVII" file="0035" n="35"/>
dentro uno dei ſoliti corpicciuoli, pel <lb/>quale prontiſſimamente ſi ruppe tutta con-<lb/>forme all’ ordinario; </s>
  <s xml:id="echoid-s111" xml:space="preserve">con queſta ſol diffe-<lb/>renza, ch’eſſendo internamente vuota, l’ <lb/>aria che d’ intorno la circondava e con <lb/>gran forza premeva, impedì che poteſſe <lb/>ſcoppiare e cader d’ogn’ intorno in pez-<lb/>zi. </s>
  <s xml:id="echoid-s112" xml:space="preserve">Ella avrebbe adunque veduta una Ca-<lb/>raffa intiera sì, ma piena d’ ogni parte <lb/>di fenditure, le quali laſciando illeſo il <lb/>collo che come più ſottile è di tutt’ al-<lb/>tra teſtura che il reſto, parevano tutte <lb/>andarſi ad unire irregolarmente a guiſa <lb/>di raggj nel centro del fondo, nel quale <lb/>a un di preſſo aveva percoſſo il corpic-<lb/>ciuolo gettatole dentro. </s>
  <s xml:id="echoid-s113" xml:space="preserve">Queſta direzio-<lb/>ne delle fenditure, detta quì di paſſag-<lb/>gio, per poco che vi ſi mediti ſopra, <lb/>parmi che debba dare anch’eſſa una gran-<lb/>diſſima probabilità al ſentimento mio. <lb/></s>
  <s xml:id="echoid-s114" xml:space="preserve">All’ aprirſi poi che ſi fece la bocca della
<pb o="XXVIII" file="0036" n="36"/>
Caraffa, ella avrebbe veduto come è na-<lb/>turale, ſcioglierſi tutto queſto compoſto, <lb/>e cadere per l’ aria eſcluſane, che dentro <lb/>precipitoſamente entrolle.</s>
  <s xml:id="echoid-s115" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s116" xml:space="preserve">Lo ſteſſo eſatto Oſſervatore provò an-<lb/>cora l’oppoſto di codeſta eſperienza; </s>
  <s xml:id="echoid-s117" xml:space="preserve">cioè <lb/>provò a rompere una Caraffa in cui era <lb/>dentro l’ aria, la quale eſternamente era-<lb/>le ſtata levata. </s>
  <s xml:id="echoid-s118" xml:space="preserve">Per far queſto, rinchiuſe-<lb/>la nella macchina pneumatica, il reci-<lb/>piente o ſia campana della quale aveva <lb/>nel vertice un buco da cui uſcir poteva <lb/>il collo della Caraffa ben luttato, ſicchè <lb/>non potea dentro trapelare per la com-<lb/>meſſura aria alcuna. </s>
  <s xml:id="echoid-s119" xml:space="preserve">L’effetto riuſcì tal <lb/>quale riuſcir doveva, cioè ruppeſi la Ca-<lb/>raffa, e ruppeſi con impeto tale a cagio-<lb/>ne dell’ aria che ſopra le gravitava, <lb/>che i frammenti urtarono e percoſſero con <lb/>sì grand’ impeto il recipiente, che infran-<lb/>to ſenz’alcun dubbio l’avrebbero, ſe prov-
<pb o="XXIX" file="0037" n="37"/>
vidamente non foſſe ſtato di metallo <lb/>Circa tutti gli altri Eſperimenti che in <lb/>lunga ſerie tentar ſi potrebbero nella mac-<lb/>china, o che ſono ſtati tentati, poichè a <lb/>queſte tre ſopraddette differenti maniere <lb/>credo io che ſi poſſan ridurre, così ſti-<lb/>mo inutile lo allungare il diſcorſo facen-<lb/>done ulteriori parole.</s>
  <s xml:id="echoid-s120" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s121" xml:space="preserve">Queſte eſperienze poſcia fatte nell’aria <lb/>e ſenz’ aria, potrebbero ſervire per con-<lb/>getturare quello che ſucceder dee nel pro-<lb/>vare le Caraſfe o ripiene, o immerſe in <lb/>qualche liquore, ſe queſte ricerche anch’ <lb/>eſſe non ſi foſſero fatte con ugual dili-<lb/>genza ed acuratezza che le altre. </s>
  <s xml:id="echoid-s122" xml:space="preserve">lmper-<lb/>ciocchè che altro è l’ aria in cui vivia-<lb/>mo ſe non un fluido leggeriſſimo, il qua-<lb/>le nè più nè meno è ſoggetto a tutte le <lb/>leggi che inviolabilmente agli altri flui-<lb/>di ha preſcritto la natura? </s>
  <s xml:id="echoid-s123" xml:space="preserve">Si romperan-<lb/>no adunque ſe loro gettaſi dentro il ſo-
<pb o="XXX" file="0038" n="38"/>
lito corpicciuolo, o ſieno queſte vuote <lb/>d’ acqua o ſieno piene, e ſi romperanno <lb/>o ſiano in eſſa immerſe o non lo ſiano. <lb/></s>
  <s xml:id="echoid-s124" xml:space="preserve">La ſol differenza che vi paſſa è, che quan-<lb/>do ſon piene, biſogna che il corpo ſia <lb/>aſſai più poſſente di quello che abbiſo-<lb/>gnarebbe ſe foſſer vuote, e tanto più lo <lb/>ſia, che ſuperate colla propria gravità <lb/>tutte le nuove reſiſtenze aggiunteſi, ri-<lb/>manga tanto di momento che baſti per <lb/>arrivare a sfregiarne il fondo. </s>
  <s xml:id="echoid-s125" xml:space="preserve">Dico tut-<lb/>te le reſiſtenze, perchè ella ſa quanto pre-<lb/>ſentemente divida l’animo dei fiſici la de-<lb/>terminazione della legge con cui mo-<lb/>vonſi i corpi nei fluidi, a ſegno che pa-<lb/>re che fino i climi e la natura dei dif-<lb/>ferenti paeſi influiſca a mantenere ſem-<lb/>pre più viva che mai queſta gran lite, <lb/>volendo i Tedeſchi una coſa, i Franceſi <lb/>un’ altra, gl’ Italiani un’ altra, e un’ altra <lb/>gl’ Ingleſi. </s>
  <s xml:id="echoid-s126" xml:space="preserve">Quello che dico dell’acqua ſia
<pb o="XXXI" file="0039" n="39"/>
detto di qualunque altro fluido, e dell’ <lb/>Argento vivo ancora, ſe poſſibil foſſe <lb/>trovare un corpo capace di rompere la <lb/>ſuperficie dei vetri, e che nell’ argento <lb/>vivo diſcendeſſe al fondo. </s>
  <s xml:id="echoid-s127" xml:space="preserve">Se reciproca-<lb/>mente poi getteraſſi il corpicciuolo den-<lb/>tro della Caraffa vuota, ma immerſa <lb/>nell’acqua o in qualche altro fluido, ſuc-<lb/>cederà lo ſteſſo che ſopra ſi è veduto <lb/>ſuccedere nell’ aria libera, ſe la Caraffa <lb/>era internamente vuota d’ aria; </s>
  <s xml:id="echoid-s128" xml:space="preserve">cioè ſi <lb/>romperà è vero con egual facilità, ma <lb/>non ſempre caderanno diviſi i frammen-<lb/>ti, imperciocchè il fluido che contra le <lb/>pareti della Caraffa preme, gli ſoſterrà, <lb/>e gli ſoſterrà con tanto maggior forza, <lb/>quanto la ſua gravità ſarà maggiore <lb/>di quella dell’ aria, avuto per altro il <lb/>dovuto riſpetto alle differenti loro al-<lb/>tezze.</s>
  <s xml:id="echoid-s129" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s130" xml:space="preserve">Il ſopranominato Geſuita nella ſua diſ
<pb o="XXXII" file="0040" n="40"/>
ſertazione ci avverte quì di una partico-<lb/>larità ben curioſa da lui oſſervata, la <lb/>quale è che quando ſi rompono immerſe <lb/>nell’ acque, vedeſi talvolta uſcire dalle <lb/>fenditure un fumo aſſai ſottile, il quale <lb/>a creder mio potrebbe darſi che naſceſſe <lb/>dallo ſprigionamento delle piccole bolle <lb/>d’ aria, che come appariſce agli occhi, <lb/>ſono rinchiuſe nelle pareti della maggior <lb/>parte dei vetri groſſi, e ſpecialmente di <lb/>quelli che non ſono ſtati a ricuocerſi nel-<lb/>la ſtufa.</s>
  <s xml:id="echoid-s131" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s132" xml:space="preserve">Un’ altra neceſſaria conſeguenza pur <lb/>cavaſi dalla maniera con cui ſi fabbrica-<lb/>no, cioè dal ſollecito ineguale raffredda-<lb/>mento, e per la quale indovinaſi la mag-<lb/>gior parte di que’ fenomeni, che in eſſe <lb/>dopo d’ averle riſcaldate ſu le brage ac-<lb/>ceſe ſi oſſervano. </s>
  <s xml:id="echoid-s133" xml:space="preserve">Il Signor Laghi ha <lb/>provato, che ſe roventaſi una Caraffa <lb/>e dappoi laſciaſi raffreddare a poco a
<pb o="XXXIII" file="0041" n="41"/>
poco ſu le brage medeſime, nel mentre <lb/>che queſte lentamente ſi vanno eſtinguen-<lb/>do, queſta diventa incapace di eſſer rot-<lb/>ta, e per quanto ſe le gettino dentro <lb/>corpi duri e puntati, reſiſte ugualmente <lb/>che ſe dopo fatta foſſe ſtata meſſa nella <lb/>camera ſuperiore alla fornace. </s>
  <s xml:id="echoid-s134" xml:space="preserve">Ha pro-<lb/>vato altresì che romponſi conforme il ſo-<lb/>lito, ſe dopo di eſſere ſtate roſſe nel fo-<lb/>co, ſi immergono ed eſtinguono nell’ <lb/>acqua fredda (eſperimento per altro aſ-<lb/>ſai difficile, perchè nell’ immergerle qua-<lb/>ſi tutte ſpontaneamente ſcoppiano) oppu-<lb/>re ſe ſi laſciano raffreddare nell’ aria or-<lb/>dinaria, con queſta differenza però, che <lb/>romponſi aſſai più debolmente e ſenza <lb/>tanto impeto come le altre; </s>
  <s xml:id="echoid-s135" xml:space="preserve">lo che in-<lb/>tenderaſſi beniſſimo ſe ſi riflette, che il <lb/>foco dei carboni, eſſendo aſſai più de-<lb/>bole del foco della fornace, potrà in <lb/>parte ſervire ai vetri che ſopra eſſo ſi
<pb o="XXXIV" file="0042" n="42"/>
pongono a riſcaldarſi, per una ſpecie <lb/>dirò così di legger cottura, equivalente <lb/>in parte ma non in tutto a quella della <lb/>ſtufa vetraria. </s>
  <s xml:id="echoid-s136" xml:space="preserve">Non romperaſſi in conſe-<lb/>guenza la Caraffa, ſe nel mentre che è <lb/>molto rovente, gettaſele dentro il cor-<lb/>picciuolo, come al contrario ſi romperà <lb/>ſe mediocre fia il calore comunicatole, <lb/>nel quale ultimo caſo vedraſſi rompere è <lb/>vero, ma romperſi con tal languidezza <lb/>e in pezzi così grandi, che intenderaſſi <lb/>da queſto quanto in lei ſia diminuita per <lb/>ragione del riſcaldamento la attività di <lb/>ſcoppiare che per l’avanti aveva.</s>
  <s xml:id="echoid-s137" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s138" xml:space="preserve">Varj altri eſperimenti ſi ſono fatti an-<lb/>cora, che ſerviranno a porre maggior-<lb/>mente in chiaro queſta piccola sì, ma <lb/>curioſa parte della fiſica. </s>
  <s xml:id="echoid-s139" xml:space="preserve">Si ſono fatte <lb/>primieramente arruotare alcune Caraffe, <lb/>e che ſiane ſucceduto ella potrà facil-<lb/>mente indovinarlo, ſe a codeſta prova
<pb o="XXXV" file="0043" n="43"/>
adatterà il piano o ſia il penſiere da mè <lb/>propoſtole. </s>
  <s xml:id="echoid-s140" xml:space="preserve">Arruotandole adunque nel <lb/>fondo più groſſo, (giacchè dai lati che <lb/>ſono ſempre più ſottili non puoſſi, rom-<lb/>pendoſi queſte nel premere che faſſi con <lb/>eſſe neceſſariamente ſopra la ruota) ſuc-<lb/>cede che internandoſi ed arrivando col-<lb/>la ruota a logorar quel luogo in cui il <lb/>vetro comincia ad eſſer più raro e in <lb/>conſeguenza più fragile, ſcoppiano que-<lb/>ſte tutte in un colpo con egual impeto <lb/>che ſe ſi foſſero nella ſolita maniera toc-<lb/>cate o punte. </s>
  <s xml:id="echoid-s141" xml:space="preserve">Una ſola cautela in far <lb/>queſto è neceſſariſſima; </s>
  <s xml:id="echoid-s142" xml:space="preserve">ed è che nell’ ar-<lb/>ruotarle ſi logorino poco a poco ed a <lb/>varie ripreſe, per impedire quel notabi-<lb/>le riſcaldamento che naſcer ſuole nei cor-<lb/>pi allorchè violentemente ſi fregano in-<lb/>ſieme: </s>
  <s xml:id="echoid-s143" xml:space="preserve">imperciocchè queſto rendele ina-<lb/>bili allo ſcoppio, ſervendo ad eſſe in <lb/>parte di cottura, non altrimenti che in
<pb o="XXXVI" file="0044" n="44"/>
quelle Caraffe che laſcianſi raffreddare <lb/>ſopra la fornace. </s>
  <s xml:id="echoid-s144" xml:space="preserve">Queſta diligenza non <lb/>avvertita fu la cauſa per la quale il Sig. <lb/></s>
  <s xml:id="echoid-s145" xml:space="preserve">Laghi facene anch’eſſo arrotare una, la <lb/>quale non ſolamente non iſcoppiò, ma <lb/>ſofferſe l’azione ſino a tanto che le ſi <lb/>fu intieramente logorato il fondo, e che <lb/>la ruota arrivò a paſſare nella inter-<lb/>na capacità. </s>
  <s xml:id="echoid-s146" xml:space="preserve">Le Caraffe adunque così <lb/>nell’ arrotarle riſcaldate come ſopra ho <lb/>detto, perderanno l’ attività di ſcoppia-<lb/>re all’ eſſere internamente sfregiate; </s>
  <s xml:id="echoid-s147" xml:space="preserve">ma <lb/>ſe mai non la perdeſſero del tutto, il <lb/>che ſarà nel caſo che il riſcaldamento <lb/>non ſia ſtato notabile, quella che loro <lb/>reſta ſarà così debole, che appena potrà <lb/>riconoſcerſi. </s>
  <s xml:id="echoid-s148" xml:space="preserve">In fatti la Caraffa fatta ar-<lb/>rotare dal Sig. </s>
  <s xml:id="echoid-s149" xml:space="preserve">Laghi reſiſtette a varie <lb/>percoſſe, alle quali certo le altre non <lb/>avrebbero reſiſtito, ed io che colle ma-<lb/>ni mie la ruppi, ricordomi ancora che
<pb o="XXXVII" file="0045" n="45"/>
romperla non potei ſe non fortemente fre-<lb/>gandola nella parte interna, e a forza <lb/>sfregiandola con una angoloſa pietra di <lb/>Corniola, e il romperla ancora non con-<lb/>ſiſtè in altro che in farle gettare una o <lb/>due fenditure al più.</s>
  <s xml:id="echoid-s150" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s151" xml:space="preserve">Fin dal principio di queſta mia, io le <lb/>diſſi che credea queſta qualità di ſcop-<lb/>piare comune a tutti i vetri i quali di <lb/>groſſezza conſiderabile non ſieno ſtati <lb/>nella ſtufa, e ſieno fatti a vaſo, cioſe4; <lb/></s>
  <s xml:id="echoid-s152" xml:space="preserve">abbiano parte eſteriore e parte interiore. </s>
  <s xml:id="echoid-s153" xml:space="preserve"><lb/>L’eſperienza è ſtata quella che me ne <lb/>ha certificato. </s>
  <s xml:id="echoid-s154" xml:space="preserve">Feci fare alle fornaci di <lb/>Kempten alcune tazze o ſcodelle, le <lb/>quali non erano che un ſegmento ben <lb/>piccolo di sfera, e quelle che nel raf-<lb/>freddarſi non andarono ſpontaneamente <lb/>in pezzi, ſi ruppero impetuoſamente con-<lb/>forme il ſolito, ad un leggeriſſimo tocco <lb/>di pietra focaja. </s>
  <s xml:id="echoid-s155" xml:space="preserve">In Bologna pure con-
<pb o="XXXVIII" file="0046" n="46"/>
ſigliai il Sig. </s>
  <s xml:id="echoid-s156" xml:space="preserve">Laghi a far fare alcune Ca-<lb/>raffe di figura aſſai diverſa dalle ordina-<lb/>rie, e ricordomi che ne facemmo alcune <lb/>quadrate, altre dal fondo piano, altre <lb/>dal fondo fatto a cono col vertice dentro <lb/>alla capacità, altre ſtriate e come diceſi <lb/>ſcannellate, altre d’altra figura ancora, e <lb/>tutte egualmente ſi ruppero ora con mag-<lb/>gior ora con minor impeto, come ordina-<lb/>riamente ſogliono far quelle delle quali ci <lb/>eravamo ſino allora ſerviti. </s>
  <s xml:id="echoid-s157" xml:space="preserve">A Venezia an-<lb/>cora l’eruditiſſimo Sig. </s>
  <s xml:id="echoid-s158" xml:space="preserve">Abate Gian-Mario <lb/>Ortes, degniſſimo allievo del celebre Aba-<lb/>te Grandi e dottiſſimo ſcrittore della ſua <lb/>vita, ha provato a farne di varie forme, <lb/>in occaſione che da me richieſto gentil-<lb/>mente com’ egli ſuole, a lui pure è piac-<lb/>ciuto di darmi mano nella eſecuzione di <lb/>queſte mie ricerche. </s>
  <s xml:id="echoid-s159" xml:space="preserve">Ne ha fatto fare al-<lb/>cune d’uniforme groſſezza, alcune altre <lb/>col fondo dentro piano e fuori conveſſo
<pb o="XXXIX" file="0047" n="47"/>
e in conſeguenza notabilmente groſſe <lb/>ma larghe ſotto il collo e lateralmente <lb/>ſchiacciate, altre col fondo piano den-<lb/>tro e fuori, e tante altre che quì ſareb-<lb/>be lungo dirle, e di tutte queſte così <lb/>differenti e varie ſtrutture ne ſono ſcop-<lb/>piate alcune, ſenza che la diverſa loro <lb/>configurazione ne variaſſe nella menoma <lb/>parte l’effetto. </s>
  <s xml:id="echoid-s160" xml:space="preserve">Diverſe pure dalle noſtre, <lb/>e con egual eſito ſento che le facciano in <lb/>Francia, perchè non laſcian loro quaſi <lb/>niente di collo, e lor danno a un di <lb/>preſſo la figura di un Uovo aperto in <lb/>una delle ſue punte, per la qual coſa le <lb/>chiamano alcuni Franceſi _Uovo filoſofico._</s>
  <s xml:id="echoid-s161" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s162" xml:space="preserve">Nel fabbricare che fannoſi codeſte Ca-<lb/>raffe i vetraj tengonle ſoſpeſe dalla can-<lb/>na di ferro per mezzo del loro collo, e <lb/>così reſtano liſcie nel fondo e ſenza _pun-_ <lb/>_tatura_ alcuna. </s>
  <s xml:id="echoid-s163" xml:space="preserve">Ho provato adunque an-<lb/>cora a far loro appiccar nel fondo la
<pb o="XL" file="0048" n="48"/>
canna, come coſtumaſi a que’ vaſi ai <lb/>quali vuolſi tornire la bocca del collo, <lb/>e tutto queſto per vedere ſe una diver-<lb/>ſa maniera di lavorarle mutava in eſſe <lb/>in qualche modo l’eſperienza; </s>
  <s xml:id="echoid-s164" xml:space="preserve">ma han-<lb/>no fatto lo ſteſſo interamente, e ſono <lb/>come l’altre nè più nè meno ſcoppiate. <lb/></s>
  <s xml:id="echoid-s165" xml:space="preserve">Col nome di _puntatura_ termine dell’ arte <lb/>vetraria di cui mi ſono ſopra ſervito, <lb/>intendo quello ſtigma che neceſſariamen-<lb/>te dalla canna di ferro colla quale ſon <lb/>fabbricati, contraggono tutti i vaſi di <lb/>vetro che hanno la bocca tornita, il qua-<lb/>le non vedendoſi nei vaſi antichi che tro-<lb/>viamo nell’urne e nei ſepolcri, ci fareb-<lb/>be credere che tutt’altra maniera aveſſe-<lb/>ro avuto i Greci o i Romani nel lavorare <lb/>il vetro, ſe Plinio non ci aſſicuraſſe del <lb/>contrario col dirci, che “aliud (Vitrum) <lb/>flatu figuratur, aliud torno teritur, aliud <lb/>argenti modo caelatur“ Ciò non oſtante
<pb o="XLI" file="0049" n="49"/>
rebbe deſiderabile che queſto Autore ci <lb/>aveſſe laſciato più minutamente deſcrit-<lb/>to il loro artificio, come ci ha laſciata <lb/>la compoſizione del vetro; </s>
  <s xml:id="echoid-s166" xml:space="preserve">imperciocchè <lb/>eſſendo ſtati coſtoro tanto più facili e <lb/>compendioſi di noi nella meccanica, chi <lb/>ſa che non trovaſſeſi un’alrro metodo <lb/>di agevolare queſt’ arte tanto neceſſaria <lb/>al pulito e civil genere di vita che og-<lb/>gi coſtumaſi ? </s>
  <s xml:id="echoid-s167" xml:space="preserve">Ma queſte ricerche quan-<lb/>to più ſono difficili e faticoſe, altret-<lb/>tanto più a lei che ad altri appartener <lb/>debbono, giacchè pare ch’ella ſia ſtata <lb/>ad arte dal deſtino ſerbata a queſta tarda <lb/>età, per diſcoprire e mettere alla chiara <lb/>luce gli enigmi più oſcuri e le reliquie <lb/>più naſcoſe dei noſtri antenati, abbando-<lb/>nate già dagli eruditi ad un perpetuo mi-<lb/>ſtero. </s>
  <s xml:id="echoid-s168" xml:space="preserve">Ma torniamo alle noſtre Caraffe, che <lb/>troppo lungo ſarebbe il diſcorſo ſe in que-<lb/>ſta vaſta provincia voleſſi mettere il piede.</s>
  <s xml:id="echoid-s169" xml:space="preserve"/>
</p>
<pb o="XLII" file="0050" n="50"/>
<p>
  <s xml:id="echoid-s170" xml:space="preserve">Dal non avere io nominato altro luo-<lb/>go che il fondo in cui toccate le Ca-<lb/>raffe col diamante ſcoppjno, potrebbe <lb/>forſe taluno credere che nel fondo ſo. <lb/></s>
  <s xml:id="echoid-s171" xml:space="preserve">lamente e non altrove, poſſaſi effettuare <lb/>queſta eſperienza. </s>
  <s xml:id="echoid-s172" xml:space="preserve">Tuttavolta ſe ben ri-<unsure/> <lb/>fletteſi al ſin qui detto, ſi ſcorgerà che <lb/>in qualunque luogo della Caraffa, ove <lb/>il vetro ſia tanto groſſo che poſſa farſi <lb/>quella diverſità di tenſione nelle due par-<lb/>ti eſterna ed interna, ivi non altrimenti <lb/>che nel fondo toccata, ſcoppierà, come <lb/>pure l’oſſervazione n’ha inſegnato. </s>
  <s xml:id="echoid-s173" xml:space="preserve">Vo-<lb/>lendo adunque noi determinare queſto <lb/>punto medio tra il collo e il fondo dal <lb/>quale, dirò così, comincj la loro fragi-<lb/>lità, ſi troverà ſicuramente ſopra quel <lb/>circolo parallelo il quale ſi può concepire <lb/>ove principia il vetro ad ingroſſarſi, e <lb/>queſto circolo ſarà talora più talora me-<lb/>no diſtante dall’ equatore della Caraffa,
<pb o="XLIII" file="0051" n="51"/>
ſecondo che ſarà ſtata maggiore o mi-<lb/>nore la quantità del vetro preſa dal ve-<lb/>trajo colla fiſtola di ferro nel fabbricar-<lb/>la, giacchè la ſola gravità della meteria <lb/>fuſa e ſtillante, è quella che fa naſcere <lb/>queſta groſſezza nel fondo e ne determi-<lb/>na il luogo da cui dee incominciare.</s>
  <s xml:id="echoid-s174" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s175" xml:space="preserve">Per compiere queſto diſcorſo, io credo <lb/>opportuno l’aggiugnere ancora due altre <lb/>al creder mio importantiſſime rifleſſioni. <lb/></s>
  <s xml:id="echoid-s176" xml:space="preserve">Sul principio di queſto ragionamento io <lb/>le diſſi, che gettando dentro le Caraffe <lb/>un piccoliſſimo pezzetto di corpo duro, <lb/>cadono in quell’iſtante medeſimo o qual-<lb/>che tempo dopo infrante in pezzi. </s>
  <s xml:id="echoid-s177" xml:space="preserve">Ora <lb/>glielo replico, e le dico di più che que-<lb/>ſto tempo talora ſi reſtringe a ſoli ſe-<lb/>condi, talora a minuti, e tal volta an-<lb/>cora benchè di rado ad ore intere. </s>
  <s xml:id="echoid-s178" xml:space="preserve">Il di-<lb/>ligentiſſimo Geſuita ſopraddetto, che col <lb/>pendolo eſattiſſimo lo ha miſurato, le
<pb o="XLIV" file="0052" n="52"/>
ne darà nella ſua diſſertazione un’ aſſai <lb/>diſtinto ragguaglio, coſa che non potrò <lb/>fare io, non eſſendo ſtato ſu queſto pun-<lb/>to molto ſcrupoloſo. </s>
  <s xml:id="echoid-s179" xml:space="preserve">Ma ſiaſi lungo o <lb/>breve quanto ſi vuol queſto tempo, pa-<lb/>re che ſe lo ſcoppio debba dipendere <lb/>dallo sfregio che dentro dei vetri faſſi <lb/>dal corpo cadente, non poſſa intenderſi <lb/>come poi tardino qualche volta a rom-<lb/>perſi, dovendo certamente farſi queſto <lb/>sfregio nel primo toccare che fa della <lb/>Caraffa il corpicciuolo. </s>
  <s xml:id="echoid-s180" xml:space="preserve">A queſta per <lb/>altro graviſſima difficoltà, la quale ſe <lb/>ſciorre non ſi poteſſe, rovinerebbe in-<lb/>tieramente e diſtruggerebbe il fin qui <lb/>detto, parmi che ſi poſſa giuſtamente <lb/>riſpondere, e ſoddisfare colle ſeguenti ri-<lb/>fleſſioni. </s>
  <s xml:id="echoid-s181" xml:space="preserve">Alloraquando è fatto il picco-<lb/>liſſimo sfregio nel fondo della Caraffa, <lb/>o queſto è grande quanto baſta accioc-<lb/>ch’ ella rompaſi, o non lo è. </s>
  <s xml:id="echoid-s182" xml:space="preserve">Se il pri-
<pb o="XLV" file="0053" n="53"/>
mo, già va in pezzi queſta e di niuno <lb/>altro diſcorſo ci è d’uopo. </s>
  <s xml:id="echoid-s183" xml:space="preserve">Se il ſecon-<lb/>do poi, io credo che a cagione della <lb/>tenſione delle parti la quale oſſerviamo <lb/>in tutti i corpi elaſtici, e ſpecialmente <lb/>nel vetro più ch’ egli è crudo, vadaſi <lb/>queſto sfregio poco a poco dilatando, <lb/>finchè giunga all’ ampiezza a cui biſogno <lb/>è che giunga perchè ſcoppj tutto il <lb/>compoſto e cada per così dire in rovi-<lb/>na. </s>
  <s xml:id="echoid-s184" xml:space="preserve">Ecco ſe pure io colgo il vero, la <lb/>cagione per cui tardano alcuna volta le <lb/>Caraffe a romperſi, ed ecco la cauſa di <lb/>codeſta ineguaglianza di ritardo, la qua-<lb/>le certo non potrà ridurſi a legge, per-<lb/>chè ridurſi a legge non può l’ effetto <lb/>od il momento della prima percoſſa. <lb/></s>
  <s xml:id="echoid-s185" xml:space="preserve">Coteſto ingrandirſi poi dello sfregio co-<lb/>ſa ſtrana non dee parere, e potrà con-<lb/>cepirſi ſenza sforzo alcuno di mente, ſe <lb/>ſi riflette allo allungarſi che fanno tal
<pb o="XLVI" file="0054" n="54"/>
volta anche ocularmente le fenditure che <lb/>gettano per qualche cauſa eſterna i ve-<lb/>tri. </s>
  <s xml:id="echoid-s186" xml:space="preserve">Chi è di noi che veduto non l’ab-<lb/>bia, ſe per efempio nel tempo maſſime <lb/>d’inverno verſaſi acqua bollente dentro <lb/>ad un fiaſco di vetro o in un groſſo <lb/>bicchier di criſtallo ? </s>
  <s xml:id="echoid-s187" xml:space="preserve">Vedonſi pure allo-<lb/>ra dilatarſi ed ingrandirſi ſucceſſivamen-<lb/>te talora più talora men celeremente le <lb/>fenditure che per lo più in ſimil caſo <lb/>ſar vi ſi ſogliono, le quali non ſi arre-<lb/>ſtano, ſe non quando il vetro ſi è fat-<lb/>to egualmente caldo che l’acqua verſa-<lb/>tavi dentro, lo che è lo ſteſſo che di-<lb/>re, ſe non quando le parti del vetro ſo-<lb/>no tutte egualmente teſe, ſuppoſto però <lb/>ch’ egli non cada in pezzi prima d’ar-<lb/>rivarvi. </s>
  <s xml:id="echoid-s188" xml:space="preserve">Di più, non ſono nè debbono <lb/>eſſere nuovi nella natura a diligente oſ-<lb/>ſervatore codeſti lenti ed inſenſibili mo-<lb/>ti, anzi io credo che neſſun corpo ſia-
<pb o="XLVII" file="0055" n="55"/>
ne eſente, lo che troppo chiaro ſi rico-<lb/>noſce, fe dopo lunga ſerie di tempo ri-<lb/>chiamaſi alla memoria il primiero antico <lb/>ſtato di qualche corpo, e ſe ne oſſerva-<lb/>no i cangiamenti poco a poco ſopravve-<lb/>nutigli.</s>
  <s xml:id="echoid-s189" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s190" xml:space="preserve">L’altra rifleſſione poi è, che talvolta <lb/>quantunque di rado, le Caraffe ſi rom-<lb/>pono benchè loro non gettiſi dentro <lb/>altro che qualcuno di quei corpi che <lb/>non credonſi atti a sfregiare la ſuperſi-<lb/>cie dei vetri. </s>
  <s xml:id="echoid-s191" xml:space="preserve">Il Sig. </s>
  <s xml:id="echoid-s192" xml:space="preserve">Laghi per eſempio <lb/>ne ha rotte alcune con un dado, altre <lb/>con una zanna di Lupo, altre con una <lb/>sferetta d’argento o con altre conſimili <lb/>coſe, e ſe pur non le ha rotte al pri-<lb/>mo gettarvele dentro, fono ſcoppiate <lb/>almeno dopo d’averle alquanto ſcoſſe, <lb/>e in conſeguenza forzato il corpo che <lb/>contenevano a balzare qua e là, e per-<lb/>coterle dall’una e dall’altre parte. </s>
  <s xml:id="echoid-s193" xml:space="preserve">La
<pb o="XLVIII" file="0056" n="56"/>
difficoltà a prima viſta, com’ella vede, <lb/>quanto è più ſemplice altrettanto pare <lb/>più forte; </s>
  <s xml:id="echoid-s194" xml:space="preserve">ma ciò nonoſtante ſarà facil-<lb/>mente ſpiegata ed alle ſuddette coſe adat-<lb/>tata, ſe penſaſi al grave momento che <lb/>debbono aver queſti corpi tanto di peſo <lb/>maggiori della ſcheggia di ſelce o di dia-<lb/>mante; </s>
  <s xml:id="echoid-s195" xml:space="preserve">ſecondariamente ſe riflettaſi, che <lb/>eſſendo le pareti di queſte Caraffe qual-<lb/>che volta ripiene di piccole bollette d’a-<lb/>ria, ne viene che quelle bolle le quali <lb/>ſono viciniſſime alla ſuperficie interna, <lb/>gonfiando all’infuori, non ſono ritenute <lb/>e coperte che da un velo, dirò così, <lb/>ſottiliſſimo di vetro, il quale certamen-<lb/>te ſi romperà, ſe contro d’eſſo o cade <lb/>o urta il corpo gettato lor dentro, lo <lb/>che io credo che baſti, perchè poi il <lb/>reſto della Caraffa o in quel momento <lb/>o poco dopo cadeſene in pezzi. </s>
  <s xml:id="echoid-s196" xml:space="preserve">L’in-<lb/>ſpezione alle volte ſenſibile della ſopra
<pb o="XLIX" file="0057" n="57"/>
mentovata ineguaglianza che hanno nel-<lb/>la ſuperficie i frammenti, la coſtanza nel <lb/>romperſi al cadervi dentro corpi atti a <lb/>sfregiare il vetro, il non romperſi che <lb/>ben di rado al cadervi dentro degli al-<lb/>tri purchè poi ancora ſieno di peſo con-<lb/>ſiderabile, il non romperſi quaſi mai ſe <lb/>loro gettanſi dentro metalli teneri e pa-<lb/>ſtoſi, come è l’oro il piombo lo ſta-<lb/>gno benchè peſantiſſimi, tutte queſte co-<lb/>ſe dico inſieme dovrebbero a creder mio <lb/>far comprendere abbaſtanza onde naſca <lb/>alle volte codeſta anomalia.</s>
  <s xml:id="echoid-s197" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s198" xml:space="preserve">Una ſol coſa ancora parea che ad in-<lb/>tieramente riſchiarare ed eſaminare co-<lb/>deſte fiſiche Caraſfe mancaſſe. </s>
  <s xml:id="echoid-s199" xml:space="preserve">Ognuno <lb/>ſa che dopo le ſagge diligentiſſime ri-<lb/>cerche del Signor Gray a Londra, e <lb/>del Signor da Fay a Parigi, ſi è final-<lb/>mente ſcoperto che moltiſſimi di que’ <lb/>corpi che noi già abbaſtanza credevamo,
<pb o="L" file="0058" n="58"/>
dai fiſici ricercati e tentati, hanno ma-<lb/>nifeſtate nuove qualità, le quali poi <lb/>hanno fatto cangiar d’ aſpetto quaſi al-<lb/>la fiſica. </s>
  <s xml:id="echoid-s200" xml:space="preserve">Ella intende che io qui voglio <lb/>indicare la nuova miſterioſa forza Elet-<lb/>trica od attrattrice, come anche la be-<lb/>ne ſtrana dotte che hanno per la mag-<lb/>gior parte i medeſimi corpi collo ſtro-<lb/>picciarli riſcaldati, di riſplendere all’oſ-<lb/>curo gettando d’ ognintorno luminoſe <lb/>ſcintille. </s>
  <s xml:id="echoid-s201" xml:space="preserve">Pareva adunque che mancaſſe <lb/>la certezza, ſe le noſtre Caraffe anch’ <lb/>eſſe foſſero di queſta ſpecie elettrica o <lb/>nò; </s>
  <s xml:id="echoid-s202" xml:space="preserve">per lo che e dal Sig. </s>
  <s xml:id="echoid-s203" xml:space="preserve">Laghi e da <lb/>me ſi ſono fatte varie eſperienze, le <lb/>quali finora non ci hanno aſſicurati di <lb/>coſa veruna. </s>
  <s xml:id="echoid-s204" xml:space="preserve">Imperciocchè quantunque <lb/>fregate e ben ben riſcaldate, non hanno <lb/>tirato corpo alcuno, nè hanno laſciato <lb/>vedere verun raggio di luce, ſia nel lo-<lb/>ro ſtato d’ integrità, ſia nel punto me-
<pb o="LI" file="0059" n="59"/>
deſimo in cui internamente percoſſe ſcop-<lb/>piavano.</s>
  <s xml:id="echoid-s205" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s206" xml:space="preserve">Dico che le noſtre oſſervazioni fino <lb/>ad ora non ci hanno ſu queſto aſſicura-<lb/>ti punto, perchè da ciò che abbiamo fat-<lb/>to non viene che non poſſano eſſere le <lb/>Caraffe elettriche anch’eſſe, e che qual-<lb/>che fiſico più felice di noi ricercando <lb/>non le poſſa ritrovar tali. </s>
  <s xml:id="echoid-s207" xml:space="preserve">Anzi ardirei <lb/>quaſi aſſerire che lo foſſero malgrado le <lb/>noſtre infruttuoſe diligenze, giacchè ve-<lb/>diamo qualunque altro vetro eſſere ſor-<lb/>nito di queſta attività, e rifonderei piu-<lb/>toſto ſulla difficoltà dell’ eſperienza ge-<lb/>loſiſſima il non averlo noi per anche po-<lb/>tuto ſcoprire. </s>
  <s xml:id="echoid-s208" xml:space="preserve">La natura è troppo fe-<lb/>conda di leggi a noi finora ſconoſciu-<lb/>te, e che di giorno in giorno ſi van-<lb/>no ſcoprendo, perchè nc<unsure/>ſſuno ardiſca <lb/>più di eſcludere con ſicurezza alcuno <lb/>dei loro effetti. </s>
  <s xml:id="echoid-s209" xml:space="preserve">Chi avrebbe mai cre-
<pb o="LII" file="0060" n="60"/>
duto che la carta, il caffè, il pane, <lb/>e tanti altri corpi poteſſero divenir foſ-<lb/>fori, ſe le diligenze infinite dell’ inſtan-<lb/>cabile oſſervatore il Sig. </s>
  <s xml:id="echoid-s210" xml:space="preserve">Bartolomeo <lb/>Beccari noſtro Bologneſe non ce lo aveſ-<lb/>ſero fatto vedere ?</s>
  <s xml:id="echoid-s211" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s212" xml:space="preserve">Da tutto queſto può ognuno conget-<lb/>turare, quanta ſomiglianza paſſi tra le <lb/>noſtre Caraffe e le tanto celebri Lagri-<lb/>me Olandeſi, o Pruſſiane, o Venezia-<lb/>ne, le quali quanto francamente ſono <lb/>ſtate finora ſpiegate dai Carteſiani mer-<lb/>cè la loro onnipotente proteiforme ma-<lb/>teria ſottile, altrettanto hanno eſer-<lb/>citato l’ ingegno di quella parte di Fi-<lb/>loſofi, i quali non ſi contentano di <lb/>ſpiegare i fenomeni della natura per un <lb/>mezzo la di cui eſiſtenza non ſi è po-<lb/>tuta ancora da alcuno provare. </s>
  <s xml:id="echoid-s213" xml:space="preserve">Ella <lb/>mi permetta che le ne faccia qui in <lb/>poche parole un parallelo, il quale ſer-
<pb o="(LIII)" file="0061" n="61"/>
virà forſe anch’eſſo a mettere più in chia-<lb/>ro l’una e l’altra di queſte due fiſiche ra-<lb/>rità. </s>
  <s xml:id="echoid-s214" xml:space="preserve">Fannoſi queſte Lagrime come tut-<lb/>to il mondo ſa, col laſciar cadere a <lb/>ſtille il vetro fluido e bollente nell’ ac-<lb/>qua fredda, per la qual coſa ritengono <lb/>tutte generalmente la figura di goccia. <lb/></s>
  <s xml:id="echoid-s215" xml:space="preserve">Chi non iſcorge da queſto artificio quell’ <lb/>ineguale raffreddamento nelle parti del <lb/>vetro, del quale ſopra a propoſito delle <lb/>Caraffe hò fatto menzione, sforzando in <lb/>queſta maniera le parti eſterne della La-<lb/>grima ad indurarſi, nel mentre che le <lb/>interne ſervono ancora e ſono infocate? </s>
  <s xml:id="echoid-s216" xml:space="preserve"><lb/>Romponſi queſte non altrimenti che le <lb/>Caraffe, egualmente nel pieno che nel <lb/>vuoto della macchina, e romponſi in <lb/>conſeguenza o ſiano immerſe o non ſiano <lb/>in qualunque fluido, e ſe ne ſono, man-<lb/>dano fuori anch’ eſſe nel romperſi che fan-<lb/>no un certo fumo, il quale ſalvo ogni er-
<pb o="(LIV)" file="0062" n="62"/>
rore io non credo poſſa eſſere altro, ſe <lb/>non l’ aria entro d’eſſe ocularmente in-<lb/>carcerata. </s>
  <s xml:id="echoid-s217" xml:space="preserve">Se pongonſi ſul foco a roven-<lb/>tarſi, e dopo ſi laſciano all’ aria libera <lb/>raffreddare, ſuppoſto che ſpontaneamente <lb/>non ſi rompano, come ſempre o quaſi <lb/>ſempre ſuccede, perdono la loro attività <lb/>di ſcoppiare, come al contrario langui-<lb/>damente la ritengono, ſe mediocre è il <lb/>calore che loro ſi comunica. </s>
  <s xml:id="echoid-s218" xml:space="preserve">Queſte pu-<lb/>re arruotandole ſcoppiano quando ſi giun-<lb/>ge a toccar colla ruota quella parte in-<lb/>teriore, ove il vetro incomincia ad eſſer <lb/>raro e fragile. </s>
  <s xml:id="echoid-s219" xml:space="preserve">E finalmente queſte non <lb/>iſcoppiano mai ſe non incomincianſi a <lb/>rompere coll’ arte, o troncando loro la <lb/>coda, o logorandole da altra parte. </s>
  <s xml:id="echoid-s220" xml:space="preserve">Poſ-<lb/>ſibile che due eſperimenti di fiſica vada-<lb/>no più d’accordo di queſti? </s>
  <s xml:id="echoid-s221" xml:space="preserve">Che s’ ella <lb/>è così, come certo dall’ eſperienza am-<lb/>maeſtrati vediamo, ragionevole conſe-
<pb o="(LV)" file="0063" n="63"/>
guenza ſarà il dire, che eſſendo queſti <lb/>i medeſimi effetti ſu due corpi ſimili o <lb/>quaſi ſimili, sì per quello che riguarda <lb/>alla materia, come per quello che riguar-<lb/>da al modo con cui ſi fanno, ragione-<lb/>vole conſeguenza dico ſarà l’ aſſerire, <lb/>che dipendano ancora dalla medeſima leg-<lb/>ge della natura. </s>
  <s xml:id="echoid-s222" xml:space="preserve">Eccole quanto fino ad <lb/>ora a quello ch’io ſo, è ſtato ricercato <lb/>ſu queſta eſperienza ed eccole ancora <lb/>quanto io credo ſufficiente, perchè que-<lb/>ſto fenomeno non debbaſi mettere più in <lb/>avvenire entro gli aſcoſi penetrali del <lb/>ſacrario della Filoſofia. </s>
  <s xml:id="echoid-s223" xml:space="preserve">E me felice ſe <lb/>aveſſi potuto dirle qualche coſa degna <lb/>della ſua approvazione; </s>
  <s xml:id="echoid-s224" xml:space="preserve">imperciocchè <lb/>chi vi è che non ſi compiaceſſe, e non <lb/>ſi gloriaſſe di meritare il ſuffragio da <lb/>un giudice tanto in ogni genere di eru-<lb/>dizione illuminato e celebre?</s>
  <s xml:id="echoid-s225" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s226" xml:space="preserve">Ma veniamo all’ altra parte di queſto
<pb o="(LVI)" file="0064" n="64"/>
ragionamento, la quale le eſporrà come <lb/>ſul principio ho promeſſo, ciò che io <lb/>penſo ſopra quelle palle di vetro vuote <lb/>ed ermeticamente chiuſe, contenenti un <lb/>qualche pezzetto di legno o altro <lb/>corpo ſtraniero. </s>
  <s xml:id="echoid-s227" xml:space="preserve">Io credo che brevemen-<lb/>te le metteremo in chiaro, ſe ſolamen-<lb/>te conſidereremo come le ſi fabbrichino <lb/>e qual coſa loro chiudaſi dentro, e chia-<lb/>ro vedremo onde naſca lo ſtrepitoſo <lb/>ſcoppiar che fanno, quando gettanſi in <lb/>terra o romponſi in qualunque altra ma-<lb/>niera. </s>
  <s xml:id="echoid-s228" xml:space="preserve">Fatta adunque che hanno gli Ar-<lb/>tefici nella ſolita guiſa una palla di ve-<lb/>tro vuota e di mediocre grandezza, la <lb/>ſtaccano dalla canna tagliandola colle <lb/>forbici, e dentro ad eſſa per il taglio <lb/>introdotto un pezzetto di legno della <lb/>groſſezza incirca d’un dito, e poco men <lb/>lungo del ſuo diametro (come moſtra <lb/>l’ anneſſa _Fig. </s>
  <s xml:id="echoid-s229" xml:space="preserve">II._) </s>
  <s xml:id="echoid-s230" xml:space="preserve">ne chiudono imme-
<pb o="(LVII)" file="0065" n="65"/>
diatamente l’ apertura, accoſtandola da <lb/>quella parte novamente al foco, dopo <lb/>di averle attaccata dalla oppoſta la verga <lb/>di ferro con cui maneggiarla. </s>
  <s xml:id="echoid-s231" xml:space="preserve">Chiuſa l’ <lb/>apertura, la ſcoſtano dal foco ſenza por-<lb/>la nella ſtufa, ed ecco ſe pure ſponta-<lb/>neamente non iſcoppia, fatta quella <lb/>palla che noi qui vogliamo eſaminare.</s>
  <s xml:id="echoid-s232" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s233" xml:space="preserve">Da codeſto metodo di fabbricarla, chi <lb/>vi è che non conoſca dipendere tutto <lb/>queſto fenomeno dall’ aria entro di lei <lb/>contenuta e compreſſa, la quale toſto <lb/>che le ſi ſchiude tutto in un momento <lb/>il varco, come faſſi quando ſi rompe, <lb/>ſcappa fuori con impeto ed eccita quel <lb/>fragore che quotidianamente ancora in <lb/>varj inſtrumenti pneumatici ſentiamo ec-<lb/>citarſi, come pur nella polvere fulminan-<lb/>te, nei cannoni, e nelle altre armi a <lb/>fuoco? </s>
  <s xml:id="echoid-s234" xml:space="preserve">Due poi ſono ſe mal non mi ap-<lb/>pongo le cagioni, per le quali l’aria den-
<pb o="(LVIII)" file="0066" n="66"/>
tro della palla imprigionata è oltre il <lb/>ſolito compreſſa ed anguſtiata. </s>
  <s xml:id="echoid-s235" xml:space="preserve">L’una è <lb/>perchè dal corpo di legno che in eſſa <lb/>rinchiudeſi, mercè del calore acutiſſimo <lb/>che da ogn’ intorno lo circonda e pene-<lb/>tra, diſchiudeſi l’ aria tutta che entro <lb/>di sè in gran copia contiene, la quale <lb/>non potendo uſcir fuori della palla per-<lb/>chè già chiuſa, reſta incarcerata malgrado <lb/>lo sforzo che fa per ſortirne. </s>
  <s xml:id="echoid-s236" xml:space="preserve">L’ altra <lb/>dipende dal non mettere la palla nella <lb/>ſolita ſtufa, imperciocchè levata appena <lb/>dal foco indurandoſi queſta e raffreddan-<lb/>doſi nella eſterna ſua ſuperficie, reſiſte <lb/>alla forza che dentro di lei va facendo <lb/>l’ aria di mano in mano che ſi va ſpri-<lb/>gionando dal legno rinchiuſo, lo che non <lb/>ſuccederebbe ſe nella ſtufa ſi metteſſe, <lb/>perchè allora perſiſtendo a cauſa del ca-<lb/>lore, nella molezza ancora per qualche <lb/>tempo il vetro, può andare poco a po-
<pb o="(LIX)" file="0067" n="67"/>
co cedendo agli urti dell’ aria, che in-<lb/>grandendo la palla ancor tenera, ſi di-<lb/>lata fino al punto dell’ equilibrio del-<lb/>la reſiſtenza del vetro e dello sfor-<lb/>zo che dentro di lui fa l’ aria per <lb/>ampliarſi lo ſpazio. </s>
  <s xml:id="echoid-s237" xml:space="preserve">Da tutto queſto ne <lb/>ſiegue, che quanto più ſarà ripieno d’ <lb/>aria compreſſa il corpo che dentro di <lb/>lei ſi rinchiude, maggiore ſarà lo ſtre-<lb/>pito che nel romper la palla faraſſi.</s>
  <s xml:id="echoid-s238" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s239" xml:space="preserve">Fra tutti gli altri corpi poi che fan-<lb/>no più ſenſibile lo eſperimento, hò tro-<lb/>vato che migliori ſono i pezzetti di un <lb/>ſottil ramo di fico verde, come quell’ <lb/>arbore che più di ogni altro è ſpugno-<lb/>ſo e di trachee arterie abbondante, per <lb/>le quali come tutte le altre piante fan-<lb/>no, riceve l’ aria e a guiſa degli ani-<lb/>mati viventi reſpira. </s>
  <s xml:id="echoid-s240" xml:space="preserve">Non faccia poi <lb/>maraviglia, che in un sì picciol corpo <lb/>qual’ è un pezzetto di ramo di arbore
<pb o="(LX)" file="0068" n="68"/>
tant’ aria contengaſi quanta biſognavi a <lb/>far queſto gioco; </s>
  <s xml:id="echoid-s241" xml:space="preserve">perchè gli è impercet-<lb/>tibile a qual ſegno la natura comprima <lb/>queſto fluido vitale nelle piante e nei <lb/>frutti. </s>
  <s xml:id="echoid-s242" xml:space="preserve">Chi di noi non ha veduto, ſenza <lb/>toccare le fiſiche eſperienze, quant’ aria <lb/>ſprigioniſi da un legno che arde, allora <lb/>quando come ce lo dipinge Dante _da_ <lb/>_un dei lati geme,_ <lb/>_e cigola per vento, che va via?_ <lb/></s>
  <s xml:id="echoid-s243" xml:space="preserve">Quanta mai da un pomo o da altro frut-<lb/>to, ſe ſopra le brage ponſi a cuocere, <lb/>durando egli alle volte molti minuti a ſof-<lb/>fiare impetuoſiſſimamente a ſegno di fare <lb/>alzar la fiamma ai carboni contra dei <lb/>quali ſoffia?</s>
  <s xml:id="echoid-s244" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s245" xml:space="preserve">Ne ſegue al contrario, che in neſſuna <lb/>maniera aumenteraſſi lo ſtrepito, ſe den-<lb/>tro alla palla in vece di legno rinchiudaſi <lb/>uno di quei corpi dai quali o niente o <lb/>quaſi niente di aria potrà ſprigionarſi.</s>
  <s xml:id="echoid-s246" xml:space="preserve">
<pb o="(LXI)" file="0069" n="69"/>
Tali appunto ſarebbero come la eſperien-<lb/>za ciha inſegnato, il ferroe qualunque al-<lb/>tro metallo, il marmoe varj altri corpi di <lb/>queſto genere. </s>
  <s xml:id="echoid-s247" xml:space="preserve">quanto adunque più pic-<lb/>cole ſaranno le palle, e quanto più gran-<lb/>de ſarà il corpo di legno che dentro loro <lb/>ſi ſerra, tanto maggiore ſarà lo ſtrepito <lb/>che nel romperſi daranno, avvertendo per <lb/>altro nel farle, che in queſto caſo fa duo-<lb/>po che ſieno robuſte e groſſe le loro pare-<lb/>ti, perchè troppo ſottili e troppo deboli, <lb/>non reſiſterebbero all urto ed allo sforzo <lb/>che dentro di loro fempre più grande an-<lb/>drà facendo l’aria, e così pria di raffred-<lb/>darſi intieramente ſcoppierebbero da ſeſteſ-<lb/>ſe. </s>
  <s xml:id="echoid-s248" xml:space="preserve">Siccome poi il calore è mezzo forſe <lb/>il più valevole per rarefar l’ aria, così ne <lb/>ſeguirà che ſe porraſſi una di queſte pal-<lb/>le in luogo aſſai caldo, come ſarebbe vi-<lb/>ciniſſima alla fiamma o ſopra i carboni ac-<lb/>ceſi, ſcoppierà queſta probabilmente do-
<pb o="(LXII)" file="0070" n="70"/>
po un qualche minuto. </s>
  <s xml:id="echoid-s249" xml:space="preserve">L’aria allora che <lb/>vorrebbe pur rarefarſi, e che contro le <lb/>pareti di vetro va ſempre più ſpingendo, <lb/>arriverà finalmente a ſorpaſſare la loro re-<lb/>ſiſtenza, e così romperaſſi la palla, e rom-<lb/>peraſſi con iſtrepito ancora maggiore di <lb/>quello che fatto avrebbe, ſe foſſeſi nel ſo-<lb/>lito modo gettata in terra. </s>
  <s xml:id="echoid-s250" xml:space="preserve">Dico proba-<lb/>bilmente ſcoppierà, perchè con ingenui-<lb/>tà parlando non poſſo aſſerirlo ſicuramen-<lb/>te, non avendo avuto maniera quì in Ger-<lb/>mania per mancanza di fornace vetraria, <lb/>di farne la prova prima di ſcriverle la <lb/>preſente.</s>
  <s xml:id="echoid-s251" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s252" xml:space="preserve">Ecco ſpiegato ancora così di paſſaggio <lb/>e per ragione di ſomiglianza quel notiſſi-<lb/>mo fenomeno famigliare per fino ai fan-<lb/>ciulli, per mezzo del quale eſtinguonſi ta-<lb/>lora all’ improviſo e con ſorpreſa dei cir-<lb/>coſtanti in una tavola i lumi, piantando <lb/>vicino al lucignolo della candela per mez-
<pb o="(LXIII)" file="0071" n="71"/>
zo di uno ſtiletto o punta che da un lato <lb/>aver ſogliono, una di quelle piccoliſſime <lb/>palle di vetro piene di acqua la metà e di <lb/>aria l’altra, e che con nome propriſſimo <lb/>ſi chiamano bombe. </s>
  <s xml:id="echoid-s253" xml:space="preserve">Il calore della fiam-<lb/>ma dilatando allora queſti due fluidi im-<lb/>prigionati e l’acqua ſpecialmente, la qua-<lb/>le per non eſſer capace di coſtrizione ar-<lb/>riva quaſi a riempiere tutto lo ſpazio ed <lb/>a comprimere in sè medeſima l’aria che a <lb/>mole inſenſibile ſi riduce, sforza dico que-<lb/>ſti due fluidi a fare tale urto contro del-<lb/>le pareti della bomba, che finalmente ce-<lb/>de anch’eſſa, e con uno ſtrepito per la di-<lb/>lei piccolezza incredibile ſcoppiando, il <lb/>vicino lume eſtingue.</s>
  <s xml:id="echoid-s254" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s255" xml:space="preserve">Molte altre coſe potrei qui aggiugne-<lb/>re, ſe io non temeſſi di prevenire inutil-<lb/>mente col mio diſcorſo quelle giuſtiſſime <lb/>illazioni, quali non il ſuo ingegno ſolamen-<lb/>te che ciò non ſarebbe gran coſa, ma quel-
<pb o="(LXIV)" file="0072" n="72"/>
lo di qualunque altro leggitore potrebbe <lb/>far da ſeſteſſo. </s>
  <s xml:id="echoid-s256" xml:space="preserve">Oltre di che troppo lun-<lb/>go ſarebbe ſe voleſſi dir tutto quello che <lb/>ſu queſti vetri potrebbeſi da fiſico ſcru-<lb/>poloſo oſſervatore conſiderare. </s>
  <s xml:id="echoid-s257" xml:space="preserve">Quello <lb/>che in generale può dirſi è, che il vetro <lb/>è uno dei corpi che più di ogni altro <lb/>ha ſomminiſtrato eſperienze e ſempre mai <lb/>nove ſcoperte alla fiſica, e Dio ſa anco-<lb/>ra quante in avvenire ſarà per ſommini-<lb/>ſtrarne. </s>
  <s xml:id="echoid-s258" xml:space="preserve">Chi potrebbe dire per eſempio <lb/>che col tempo non abbiaſi da veder que-<lb/>ſto corpo che ora ad ogni benchè legger <lb/>percoſſa è tanto fragile, ridotto a mag-<lb/>gior durezza, o veramente ad eſſer più <lb/>duttile fuori del foco e maneggiabile? <lb/></s>
  <s xml:id="echoid-s259" xml:space="preserve">Certamente che ai giorni noſtri lo ſco-<lb/>pritore di queſto importante ſecreto non <lb/>dovrebbe temere il ſiniſtro incontro che <lb/>ebbe a Roma quell’ altro che al tempo <lb/>di Tiberio pare lo aveſſe trovato, la cui
<pb o="(LXV)" file="0073" n="73"/>
officina al riferir di Plinio fu in ricom-<lb/>penſa diſtrutta immediatamente ed abo-<lb/>lita, acciocchè con queſta nova ſpecie <lb/>di vetro non veniſſe a perdere di prez-<lb/>zo l’ argento e l’ oro, che fin da quei <lb/>giorni adornava in gran copia e copriva <lb/>le laute menſe Romane. </s>
  <s xml:id="echoid-s260" xml:space="preserve">Chi può con-<lb/>cepir coſa foſſero mai quelle due tazze <lb/>di criſtallo che al dire dello ſteſſo iſto-<lb/>rico ſividero a Roma nel tempo di Ne-<lb/>rone, e che furono pagate per fino a <lb/>ſei mila ſeſterzj? </s>
  <s xml:id="echoid-s261" xml:space="preserve">Chi mai creduto avreb-<lb/>be (per paſſare ad eſempj più recenti e <lb/>meno ſoſpetti) che il vetro poteſſe giu-<lb/>gnere ad eſſer talmente pieghevole, che <lb/>ceder poteſſe agl’ impulſi dell’ aria non <lb/>altrimenti che una tenuiſſima laſtra di <lb/>mettallo o una membrana? </s>
  <s xml:id="echoid-s262" xml:space="preserve">e pure il Sig. <lb/></s>
  <s xml:id="echoid-s263" xml:space="preserve">Lentilio Profeſſore di Filoſofia a Nort-<lb/>linguen fino dall’ anno 1684 nelle Efe-<lb/>meridi di Germania ce lo moſtrò in quel-
<pb o="(LXVI)" file="0074" n="74"/>
<anchor type="handwritten" xlink:label="hd-0074-01a" xlink:href="hd-0074-01"/>
le maraviglioſe Caraffe delle quali ei <lb/>parla. </s>
  <s xml:id="echoid-s264" xml:space="preserve">Queſte a quello che dice, (non a-<lb/>vendo io mai avuto la ſorte di vederne <lb/>alcuna, malgrado ogni poſſibile diligen-<lb/>za) ſono di un vetro ſottiliſſimo, han-<lb/>no il collo aſſai lungo e ſtretto e la lo-<lb/>ro capacità piatta, cioè molto più lar-<lb/>ga che alta. </s>
  <s xml:id="echoid-s265" xml:space="preserve">Il loro fondo è ſempre o <lb/>all’ infuori conveſſo o all’ indentro con-<lb/>cavo, e ſe è il primo, ponendo all’ ori-<lb/>ficio della Caraffa la bocca e ſucchian-<lb/>done deſtramente l’ aria contenuta, ve-<lb/>deſi che il fondo ritiraſi indentro e con <lb/>terribile ſtrepito di conveſſo ch’ egli era <lb/>diventa concavo. </s>
  <s xml:id="echoid-s266" xml:space="preserve">Reciprocamente ſe al-<lb/>lora ſoffiaſi novamente l’ aria dentro al-<lb/>la Caraffa, ritorna il fondo con ugual <lb/>rumore a diventar conveſſo qual prima. <lb/></s>
  <s xml:id="echoid-s267" xml:space="preserve">Quali belle ſcoperte forſe non ſi fareb-<lb/>bero da qualche paziente oſſervatore, ſe <lb/>prendeſſe ad eſaminar la maniera con cui
<pb o="(LXVII)" file="0075" n="75"/>
<anchor type="handwritten" xlink:label="hd-0075-01a" xlink:href="hd-0075-01"/>
queſte ſi fannoe ad ampliarla? </s>
  <s xml:id="echoid-s268" xml:space="preserve">Qual van-<lb/>taggio non recherebbeſi alla vita civile <lb/>ed all’economia, e quale comodità nel-<lb/>lo ſteſſo tempo non procaccierebbeſi agl’ <lb/>indagatori della natura, ſe togliere un <lb/>poco della ſua rigidezza ſi poteſſe al ve-<lb/>tro, del quale chi vi è che non ſappia <lb/>quale uſo ampliſſimo ſi tragga nella fab-<lb/>brica delle macchine e degli utenſilj del-<lb/>la Fiſica eſperimentale? </s>
  <s xml:id="echoid-s269" xml:space="preserve">Ma forſi trop-<lb/>po tardi mi accorgo che oltre il dovere <lb/>io mi ſono ſcrivendo eſteſo, ed ho non <lb/>volendo perduto quell’ornamento cui ſo-<lb/>lo poteva ſperare, voglio dire il pregio <lb/>della brevita. </s>
  <s xml:id="echoid-s270" xml:space="preserve">Ma mettendo il piede in <lb/>una provincia sì vaſta e sì dilettevole, <lb/>chi mai può a mezzo il cammino arre-<lb/>ſtarſi?</s>
  <s xml:id="echoid-s271" xml:space="preserve"/>
</p>
<div xml:id="echoid-div6" type="float" level="2" n="1">
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  <handwritten xlink:label="hd-0075-01" xlink:href="hd-0075-01a"/>
</div>
<p>
  <s xml:id="echoid-s272" xml:space="preserve">Non poſſo qui diſpenſarmi dal dirle, <lb/>che grandiſſima mano coll’opera loro mi <lb/>han dato nella eſecuzione di codeſte mie
<pb o="(LXVIII)" file="0076" n="76"/>
fiſiche ricerche, qui in Auguſta l’erudi-<lb/>tiſſimo Sig. </s>
  <s xml:id="echoid-s273" xml:space="preserve">Canonico Giambattiſta Baſſi Bo-<lb/>logneſe attual Conſigliere eccleſiaſtico di <lb/>S. </s>
  <s xml:id="echoid-s274" xml:space="preserve">A. </s>
  <s xml:id="echoid-s275" xml:space="preserve">Elettorale di Magonza e di S. </s>
  <s xml:id="echoid-s276" xml:space="preserve">A. <lb/></s>
  <s xml:id="echoid-s277" xml:space="preserve">S. </s>
  <s xml:id="echoid-s278" xml:space="preserve">il noſtro clementiſſimo Padrone, ed <lb/>in Bologna fino da quando io vi era il <lb/>dotto Sig. </s>
  <s xml:id="echoid-s279" xml:space="preserve">Abate Petronio Matteucci A-<lb/>ſtronomo ſoſtituito al celebre Sig. </s>
  <s xml:id="echoid-s280" xml:space="preserve">Euſta-<lb/>chio Zanotti nel Oſſervatorio del noſtro <lb/>Inſtituto delle ſcienze, amici miei tutti <lb/>non meno per la dottrina loro che per <lb/>la lor corteſia e gentilezza cariſſimi.</s>
  <s xml:id="echoid-s281" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s282" xml:space="preserve">Già che poi con la menzione della <lb/>bella ugualmente che letterata Verona <lb/>io diedi principio, mi permetta che col-<lb/>la medeſima ancora imponga fine. </s>
  <s xml:id="echoid-s283" xml:space="preserve">Di <lb/>coteſta vaga Città piena di luminoſi re-<lb/>ſti della veneranda Romana antichità, <lb/>non poſſono a meno di non parlare vo-<lb/>lontieriſſimo gli amanti di così fatte co <lb/>ſe una ſol volta che l’ abbian veduta.</s>
  <s xml:id="echoid-s284" xml:space="preserve">
<pb o="(LXIX)" file="0077" n="77"/>
Alloraquando io per coſtì ultimamente <lb/>paſſai, vidi preſſo che finita la nuova e <lb/>rara maraviglia, che tale ſenza far tor-<lb/>to al vero può chiamarſi, della qua-<lb/>le a lei ſolamente la Repubblica lettera-<lb/>ria è debitrice, e per cui non ſarà più in <lb/>avvenire il primo frà le Romane reliquie <lb/>ad eſſer nominato il Veroneſe Amfiteatro. <lb/></s>
  <s xml:id="echoid-s285" xml:space="preserve">Parlo del Muſeo incomparabile d’antiche <lb/>Inſcrizioni e baſſi rilevi, da lei raccolto <lb/>con l’applicazione e ricerca di ben trent’ <lb/>anni, ſenza riguardo a ſpeſe; </s>
  <s xml:id="echoid-s286" xml:space="preserve">e colloca-<lb/>to non già nel ſuo privato Palazzo, ma <lb/>nel gran Cortile dell’Accademia a bene-<lb/>fizio pubblico. </s>
  <s xml:id="echoid-s287" xml:space="preserve">Sento da molti venuti d’ <lb/>Italia, che la nobiliſſima collocazione ſia <lb/>già arrivata a termine, avendovi concor-<lb/>ſo molti ſpiriti nobili, amatori delle co-<lb/>ſe grandi. </s>
  <s xml:id="echoid-s288" xml:space="preserve">Mi dicono che fa ora un bel-<lb/>liſſimo vedere il portichetto da lei archi-<lb/>tettato con 50 colonette Doriche intor-
<pb o="(LXX)" file="0078" n="78"/>
no intorno per difeſa di così dotte an-<lb/>ticaglie e per comodo di chi le vuole oſ-<lb/>ſervare. </s>
  <s xml:id="echoid-s289" xml:space="preserve">Chi crederebbe mai di poter ve-<lb/>dere meſſe inſieme cento Inſcrizioni Gre-<lb/>che, poco manco numero di pezzi figu-<lb/>rati, quattro Arabiche, 25 Etruſche ſciel-<lb/>te fra le quali cinque rilevi iſtoriati d’ <lb/>alabaſtro di Volterra. </s>
  <s xml:id="echoid-s290" xml:space="preserve">Io confeſſo che <lb/>reſtai ſorpreſo e ſtupito, nel ritrovar le <lb/>Romane ordinate e diviſe in claſſi, con <lb/>tante votive, tante imperatorie, tante <lb/>militari, tante pertinenti a dignità e ma-<lb/>giſtrati, a ſpettacoli, ad arti e meſtieri, <lb/>e due belle in metallo. </s>
  <s xml:id="echoid-s291" xml:space="preserve">E poi le Cri-<lb/>ſtiane, e una ſerie di medio evo fino <lb/>al 1300 In ſomma io tengo che la ſua <lb/>patria doverà col tempo niente meno la <lb/>ſua fama a lei che a Catullo, a Plinio, <lb/>e a tanti altri che in ogni tempo ha <lb/>avuti. </s>
  <s xml:id="echoid-s292" xml:space="preserve">Saviamente la noſtra Accademia <lb/>delle Scienze volle annoverarla nel ſuo
<pb o="(LXXI)" file="0079" n="79"/>
numero come prima quella d’Inghilterra e <lb/>la Reale di Francia.</s>
  <s xml:id="echoid-s293" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s294" xml:space="preserve">E ben ella colle varie ſue opere e fi-<lb/>ſiche ed erudite ſa rendere a tali Acca-<lb/>demie tutto quel luſtro che ne ritrae. </s>
  <s xml:id="echoid-s295" xml:space="preserve">Io <lb/>le auguro tranquilità ed ozio opportuno <lb/>per dar compimento quanto volge in men-<lb/>te ſopra _la forza del fuoco_, materia che darà <lb/>forſe motivo a qualch’ altra eſperienza <lb/>con la ſua gran lente uſtoria, della qua-<lb/>le io non ho veduta la più grande. </s>
  <s xml:id="echoid-s296" xml:space="preserve">Un <lb/>dotto amico qui al quale ne ho parlato, <lb/>molto sì maraviglia, come codeſta all’in-<lb/>contro delle due famoſe di Fiorenza e <lb/>di Parigi, ſia di due pezzi, fra i quali <lb/>perchè abbrugi s’ infonde acqua o altro <lb/>liquore. </s>
  <s xml:id="echoid-s297" xml:space="preserve">Ed un altro che ha veduto il <lb/>libretto delle _Oſſervazioni della Cometa, e_ <lb/>_delli due Ecliſſi Lunari_, fatte in Verona nel-<lb/>la di lei Specola dalli Signori Gian-Pao-<lb/>lo Guglienzi, e Seguier, con le quali
<pb o="(LXXII)" file="0080" n="80"/>
hanno determinata la longitudine di Vero-<lb/>na preciſamente, non ſa ſaziarſi di lodarlo. <lb/></s>
  <s xml:id="echoid-s298" xml:space="preserve">Ma io non farei mai fine, e mentre ſer-<lb/>vo al piacere di trattenermi ſeco, non <lb/>conſidero di quanto le ſono nojoſo; </s>
  <s xml:id="echoid-s299" xml:space="preserve">però <lb/>altro non aggiungo.</s>
  <s xml:id="echoid-s300" xml:space="preserve"/>
</p>
<pb file="0081" n="81"/>
</div>
<div xml:id="echoid-div8" type="section" level="1" n="7">
<head xml:id="echoid-head24" xml:space="preserve">DELLA <lb/>DIVERSA VELOCITA' DEL SUONO. <lb/>ALTRA LETTERA</head>
<pb file="0082" n="82"/>
<pb o="LXXV" file="0083" n="83"/>
</div>
<div xml:id="echoid-div9" type="section" level="1" n="8">
<head xml:id="echoid-head25" style="it" xml:space="preserve">SIGNOR MARCHESE</head>
<p>
  <s xml:id="echoid-s301" xml:space="preserve">NOn credeſſe ella già che <lb/>io mi foſſi dimenticato, <lb/>che tra i moltiſſimi debi-<lb/>ti che io ho con lei, <lb/>ho quello ancora di nar-<lb/>rarle l’ iſtoria di quelle oſſervazioni <lb/>che io feci per l’ Accademia noſtra <lb/>dell’ Inſtituto circa la propagazione del <lb/>ſuono. </s>
  <s xml:id="echoid-s302" xml:space="preserve">Così mi foſſe facile il ſod-<lb/>disfare a quelli, come mi ſarà a que-
<pb o="LXXVI" file="0084" n="84"/>
ſto. </s>
  <s xml:id="echoid-s303" xml:space="preserve">Facciamolo adunque brevemente, <lb/>e ſuppliſca queſto pregio alla mancan-<lb/>za di tanti altri, perchè prevedo già <lb/>che queſta mia lettera nata in mezzo a <lb/>mille altri penſieri, tale ſarà per avven-<lb/>tura, che avrà biſogno di queſto benchè <lb/>povero e ſcarſo merito.</s>
  <s xml:id="echoid-s304" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s305" xml:space="preserve">Da lunghiſſimo tempo in qua hanno <lb/>conoſciuto gli Uomini propagarſi il ſuo-<lb/>no ſuceſſivamente, e ſentirſi aſſai più <lb/>preſto nei luoghi vicini al ſuo princi-<lb/>pio, di quello che ſentaſi nei luoghi lon-<lb/>tani. </s>
  <s xml:id="echoid-s306" xml:space="preserve">Seneca nelle ſue naturali quiſtioni <lb/>ſerveſi di queſta notizia per fare animo <lb/>a quelli che al rumore di grave tuono <lb/>tremano da capo a piedi, e temono il <lb/>fulmine che credono uſcire in quel mo-<lb/>mento dalle nubi e cader ſopra il tetto <lb/>della lor caſa. </s>
  <s xml:id="echoid-s307" xml:space="preserve">Ei dice che neſſuno è <lb/>ſtato mai ſpaventato dalla folgore, ſe <lb/>non dopo di eſſere già dal pericolo ſcam-
<pb o="LXXVII" file="0085" n="85"/>
pato, volendo dire con ciò, che il di lei <lb/>ſtrepito per la lentezza ſua nel propagar-<lb/>ſi, non giugne all’ orecchio noſtro, ſe <lb/>non dopo che il foco dalle nubi lancia-<lb/>to nello ſteſſo momento, ha diroccata <lb/>quella Torre, od atterrata quella Rove-<lb/>re ſu cui a ſorte andò a cadere. </s>
  <s xml:id="echoid-s308" xml:space="preserve">Quindi <lb/>Plinio ci dice, che “Fulgetrum prius <lb/>cerni quam Tonitrum audiri (cum ſi-<lb/>mul fiant) certum eſt“</s>
</p>
<p>
  <s xml:id="echoid-s309" xml:space="preserve">Se queſti ingegnoſiſſimi Filoſoſi dell’ <lb/>antichità foſſero però viſſuti ai giorni <lb/>noſtri, ed aveſſero letta la di lei lettera <lb/>al Valliſnieri, avrebbero mutato parere, ed <lb/>avrebbero conoſciuta la verità nell’ eſpe-<lb/>rienza ch’ ella ne fece a Foſdinuovo, <lb/>e nelle ragioni che conſeguirono al te-<lb/>ſtimonio degli occhi.</s>
  <s xml:id="echoid-s310" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s311" xml:space="preserve">Benchè ſi conoſceſſe adunque che il <lb/>ſuono nell’ andare dall’ uno ad un’ altro <lb/>luogo impiegava una parte di tempo
<pb o="LXXVIII" file="0086" n="86"/>
ſenſibile, neſſuno ch’ io ſappia ha però <lb/>nei ſecoli andati avuta mai la curioſità <lb/>d’ indagare quanto queſta eſſer doveſſe. <lb/></s>
  <s xml:id="echoid-s312" xml:space="preserve">Gaſſendo in Francia s’io non erro, fu il <lb/>primo che volſe l’ animo a tal penſiero, <lb/>ed a forza di oſſervazioni determinò vo-<lb/>lervi un minuto ſecondo di tempo, per-<lb/>chè il ſuono ſcorreſſe mille e quattro-<lb/>cento ſeſſantatrè piedi di quel paeſe. </s>
  <s xml:id="echoid-s313" xml:space="preserve">Gli <lb/>Accademici di Firenze come ella ſa, non <lb/>contenti di queſta aſſerzione, vollero <lb/>queſte ed altre oſſervazioni replicare an-<lb/>ch’eſſi in Toſcana eſattamente, e tutte <lb/>ſono regiſtrate nel libro elegantiſſimo di <lb/>eſperienze da loro laſciatoci. </s>
  <s xml:id="echoid-s314" xml:space="preserve">Trovarono <lb/>adunque che percorreva lo ſpazio di pie-<lb/>di 1175 in un minuto ſecondo, differen-<lb/>za aſſai ſenſibile riſpetto a quelle del <lb/>Gaſſendo. </s>
  <s xml:id="echoid-s315" xml:space="preserve">I Signori Caſſini, Picard, Ro-<lb/>mer, Huygen in Franciae altrove, volle-<lb/>ro anch’ eſſi accertarſi di queſto fatto,
<pb o="LXXIX" file="0087" n="87"/>
e replicate le eſperienze, trovarono che <lb/>in un ſecondo di tempo ſcorreva il ſuo-<lb/>no la lunghezza di 1080 piedi del Re. <lb/></s>
  <s xml:id="echoid-s316" xml:space="preserve">Gl’Ingleſi con quello ſpirito di diſſiden-<lb/>za a cui di tante belle ſcoperte nella <lb/>ſiſica ſiam debitori, inſtituirono una nuo-<lb/>va ſerie di oſſervazioni nell’ Inghilterra <lb/>eſeguite dai Sig. </s>
  <s xml:id="echoid-s317" xml:space="preserve">Flamſted, Halley ed al-<lb/>tri, e riferite nelle Tranſazioni Anglica-<lb/>ne nel meſe di Gennajo dell’ anno 1708, <lb/>e con eſſe determinarono, che il ſuono <lb/>impiegava il ſolito tempo di un ſecondo <lb/>per iſcorrere 1142 piedi d’ Inghilterra, <lb/>miſura non molto diſtante dalla già tro-<lb/>vata in Francia. </s>
  <s xml:id="echoid-s318" xml:space="preserve">La dilicatezza Ingleſe, <lb/>la quale non ſi è mai quietata quando <lb/>in tutte le ſcienze non ha fatto un paſ-<lb/>ſo più avanti, non contentoſſi nè pur <lb/>queſta volta di una tale determinazione. </s>
  <s xml:id="echoid-s319" xml:space="preserve"><lb/>Soſpettarono quei diligentiſſimi ſiloſofi, <lb/>che le differenti coſtituzioni dell’ aria po-
<pb o="LXXX" file="0088" n="88"/>
teſſero influire ancora qualche cangia-<lb/>mento ſopra il ſuono, ed oſſervaronlo <lb/>in varj ſtati dell’ atmosfera ed in varie <lb/>ſtagioni dell’ anno. </s>
  <s xml:id="echoid-s320" xml:space="preserve">Dopo lunghe e dili-<lb/>gentiſſime prove, determinarono finalmen-<lb/>te eſſer coſtante la velocità del ſuono in <lb/>qualunque vogliaſi congiuntura, e anda-<lb/>re egualmente celere ſia ſereno il cielo <lb/>o nuvoloſo, cada pure la pioggia o ne-<lb/>vichi, ſiaſi eſtate o inverno. </s>
  <s xml:id="echoid-s321" xml:space="preserve">I venti ſol-<lb/>tanto parre che turbaſſero l’ univerſalità <lb/>di queſto canone, dicendo che ſe ſpira-<lb/>no a ſeconda del ſuono lo fanno anda-<lb/>re un poco più preſto, o lo ritardano <lb/>ſe la lor direzione a queſto è contraria</s>
</p>
<p>
  <s xml:id="echoid-s322" xml:space="preserve">Su queſte oſſervazioni, tralaſciandone <lb/>varie altre fatte dal Padre Merſan, dal <lb/>Padre Lana, dal Sig. </s>
  <s xml:id="echoid-s323" xml:space="preserve">Perrault e da al-<lb/>tri, ſi acquietarono i filoſoſi lo ſpazio <lb/>almeno di una trentina<gap/> d’ anni, allora-<lb/>quando l’ anno 1738 <gap/>terminarono a
<pb o="LXXXI" file="0089" n="89"/>
Parigi di tornare un poco a ricercare <lb/>queſta quaſi abbandonata provincia. </s>
  <s xml:id="echoid-s324" xml:space="preserve">II <lb/>Sig. </s>
  <s xml:id="echoid-s325" xml:space="preserve">Caſſini di Toury, il Sig. </s>
  <s xml:id="echoid-s326" xml:space="preserve">Maraldi, <lb/>il Sig. </s>
  <s xml:id="echoid-s327" xml:space="preserve">Abate de la Caille ed altri Ac-<lb/>cademici delle Scienze ne furono incari-<lb/>cati. </s>
  <s xml:id="echoid-s328" xml:space="preserve">Le Memorie di quell’inſigne Acca-<lb/>demia narrando in quell’anno per eſteſo <lb/>tutto quello che fecero, mi diſpenſano <lb/>dal replicarne qui l’ iſtoria. </s>
  <s xml:id="echoid-s329" xml:space="preserve">Dirò ſolo <lb/>che le loro oſſervazioni determinarono, <lb/>che il ſuono ſcorre 173 Teſe in ogni <lb/>ſecondo il che equivale a 1038 piedi fran-<lb/>ceſi; </s>
  <s xml:id="echoid-s330" xml:space="preserve">che confermarono l’ oſſervazione del <lb/>Flamſted e dell’ Halley, chei venti ſecon-<lb/>di o avverſi alterano la celerità del ſuono, <lb/>come non lo alterano punto ſe ſpirano <lb/>ad angoli retti ſopra la ſua direzione; <lb/></s>
  <s xml:id="echoid-s331" xml:space="preserve">confermarono non eſſervi differenza alcu-<lb/>na tra la celerità del ſuono nel tempo <lb/>ſereno e nel piovoſo, nella notte e nel <lb/>giorno, e in varie altre circoſtanze.</s>
  <s xml:id="echoid-s332" xml:space="preserve"/>
</p>
<pb o="LXXXII" file="0090" n="90"/>
<p>
  <s xml:id="echoid-s333" xml:space="preserve">Prima che a noi in Italia giugneſſe <lb/>queſta notizia, che ſolo giunſeci dopo <lb/>la ſtampa degli Atti di quell’ accademia, <lb/>avendo io letto le Tranſazioni anglica-<lb/>ne, vennemi voglia l’anno 1740 di pro-<lb/>vare in Bologna alcuna delle oſſervazio-<lb/>ni che fecero a Londra, e ſpecialmente <lb/>quella per cui dicono non aver’ eſſi tro-<lb/>vato divario alcuno tra la celerità del <lb/>ſuono nell’ Inverno e nell’Eſtate. </s>
  <s xml:id="echoid-s334" xml:space="preserve">Pareva-<lb/>mi ſtrano che eſſendo nel rigido freddo <lb/>l’aria condenſatiſſima riſpetto alla rarefa-<lb/>zione che aver dee nel caldo dell’ eſtate, <lb/>parevami ſtrano dico, che neſſuna doveſ-<lb/>ſe poi trovarſi nel ſuono che dai di lei <lb/>tremori è propagato.</s>
  <s xml:id="echoid-s335" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s336" xml:space="preserve">La ſtagione caldiſſima che già inco-<lb/>minciava a farſi ſentire, parve invitar-<lb/>mi a mettere all’ opera il già diviſato <lb/>penſiere, cioè a provare quale celerità <lb/>aveſſe il ſuono nell’ eſtate, per parago-
<pb o="LXXXIII" file="0091" n="91"/>
narla poi con quello che avrei trovato <lb/>nell’ inverno venturo. </s>
  <s xml:id="echoid-s337" xml:space="preserve">Eccole i luoghi <lb/>che determinai per fare le oſſervazioni. <lb/></s>
  <s xml:id="echoid-s338" xml:space="preserve">La fortezza Urbana poſta ſu le frontiere <lb/>del Modoneſe fu l’uno, l’altro fu il Con-<lb/>vento dei Padri Zoccolanti dell’ oſſervan-<lb/>za. </s>
  <s xml:id="echoid-s339" xml:space="preserve">Giace la prima ſu la ſtrada maeſtra che <lb/>conduce a Modona in una pianura preſſo <lb/>a poco a Ponente-maeſtro di Bologna, <lb/>ed è il ſecondo ſu una collina al Mezzodì <lb/>di una parte della Città, luogo aſſai ſco-<lb/>perto. </s>
  <s xml:id="echoid-s340" xml:space="preserve">Determinai queſto Convento, pri-<lb/>ma perchè da lui chiariſſimamente ſcor-<lb/>geſi anche ſenza cannocchiale la fortez-<lb/>za, malgrado la diſtanza di tredici e più <lb/>delle noſtre miglia; </s>
  <s xml:id="echoid-s341" xml:space="preserve">ſecondariamente per-<lb/>chè non è lontano dalla Città che il pic-<lb/>col viaggio di una mezz’ ora in circa.</s>
  <s xml:id="echoid-s342" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s343" xml:space="preserve">La bontà e corteſia di Monſ. </s>
  <s xml:id="echoid-s344" xml:space="preserve">Gian-<lb/>Carlo Molinari Vicelegato allor di Bolo-<lb/>gna, il quale con infinito amore e libe-
<pb o="LXXXIV" file="0092" n="92"/>
ralità protegge e ſeconda gli ſtudj tutti <lb/>e le belle arti, mi fornirono tutti i mezzi <lb/>neceſſarj per le mie oſſervazioni. </s>
  <s xml:id="echoid-s345" xml:space="preserve">Imper-<lb/>ciocchè ei diede ordine che al giorno da <lb/>me creduto opportuno, ſi ſparaſſero al-<lb/>la fortezza tanti cannoni quanti io av-<lb/>rei creduto neceſſarj pel biſogno noſtro. <lb/></s>
  <s xml:id="echoid-s346" xml:space="preserve">La notte adunque che precedeva i dicia-<lb/>nove di Agoſto, accordai che foſſe ſta-<lb/>bilita per notare dall’Oſſervanza la cele-<lb/>rità con cui il ſuono di un cannone co-<lb/>là ſparato ſarebbe giunto all’ orecchio <lb/>noſtro.</s>
  <s xml:id="echoid-s347" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s348" xml:space="preserve">Pregati il Sig. </s>
  <s xml:id="echoid-s349" xml:space="preserve">Euſtachio Zanotti e il Sig. <lb/></s>
  <s xml:id="echoid-s350" xml:space="preserve">Abate Petronio Matteucci, ambo Aſtro-<lb/>nomi dell’oſſervatorio noſtro dell’Inſtitu-<lb/>to ed amici miei ornatiſſimi a venir me-<lb/>co verſo la ſera al Convento ſtabilito, <lb/>vi portammo un’ orologio aſtronomico <lb/>a cicloide, che batteva eſattiſſimamente <lb/>i ſecondi. </s>
  <s xml:id="echoid-s351" xml:space="preserve">Ella avrebbe riſo ſe ci aveſſe
<pb o="LXXXV" file="0093" n="93"/>
veduti circondati da tutti tutti i Frati di <lb/>quel Convento, ai quali la novità della <lb/>coſa e la curioſità non permetteva l’an-<lb/>dar quella notte a letto ad aſpettare <lb/>dormendo il ſegno del mattutino. </s>
  <s xml:id="echoid-s352" xml:space="preserve">Avvez-<lb/>zi quei buoni Padri ad un’ altro genere <lb/>di fiſica, non potevano capire come noi <lb/>chiamaſſimo ricerche fiſiche codeſte ma-<lb/>teriali oſſervazioni, e raccontavaci ogni-<lb/>un di loro quello che credeva poterci in <lb/>eſſe dar lume.</s>
  <s xml:id="echoid-s353" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s354" xml:space="preserve">Fra queſte novelle aſpettavamo l’ ora <lb/>del primo ſtrepito del cannone, giunto il <lb/>quale raccomandandoci con premura che <lb/>quei buoni Padri aveſſero la bontà di oſſer-<lb/>vare in avvenire quel ſilenzio che tanto a lo-<lb/>t<unsure/>o più che ad altri doverebbe eſſer facile, <lb/>vedemo finalmente nell’ oſcuro della notte <lb/>lampeggiare ſull’ orizzonte il foco del can-<lb/>none. </s>
  <s xml:id="echoid-s355" xml:space="preserve">Cominciaronſi allora a contare i <lb/>ſecondi, nè arrivò a noi il ſuono pri-
<pb o="LXXXVI" file="0094" n="94"/>
ma che contando al ſettanteſimo ſeſto <lb/>non foſſimo giunti. </s>
  <s xml:id="echoid-s356" xml:space="preserve">Replicoſi per quattro <lb/>volte in quella ſera l’ oſſervazione, e in <lb/>tutte vedemmo eſſer coſtante la celerità <lb/>del ſuono, ed impiegare un minuto e ſe-<lb/>dici ſecondi eſattiſſimi per venire dalla <lb/>fortezza Urbana al Convento.</s>
  <s xml:id="echoid-s357" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s358" xml:space="preserve">Ciò fatto perchè non reſtaſſe dubbio <lb/>alcuno della giuſtezza e puntualità del <lb/>pendolo noſtro, da cui tutta dipendea <lb/>la certezza del noſtro eſperimento, lo <lb/>portammo all’ oſſervatorio, dove con eſ-<lb/>ſo notoſſi il numero dei ſecondi che <lb/>intercedevano tra il paſſaggio di due ſtel-<lb/>le vicine pel filo orario di un cannocchia-<lb/>le in meridiano, per vedere ſe egual nu-<lb/>mero di ſecondi ci darebbe, come vera-<lb/>mente ci diede, e ciò ſia dtto adeſſo <lb/>per allora, nell’ inverno replicando que-<lb/>ſto aſtronomico confronto. </s>
  <s xml:id="echoid-s359" xml:space="preserve">So che alcu-<lb/>ni ſi maraviglieranno di una delicatezza
<pb o="LXXXVII" file="0095" n="95"/>
tanto ſcrupoloſa, quaſichè per l’ allun-<lb/>gamento o l’ accorciamento dei pendoli <lb/>nelle ſtagioni più o men calde, aveſſe <lb/>potuto naſcere differenza ſenſibile nel pic-<lb/>ciol tratto di ſettanta in ottanta vibra-<lb/>zioni. </s>
  <s xml:id="echoid-s360" xml:space="preserve">Ma ſe penſeranno che non ſem-<lb/>pre ſi prendono precauzioni per il biſo-<lb/>gno di prenderne, ma talvolta ancora <lb/>per prevenire le obbiezioni che taluno <lb/>far potrebbe, tanto più che nelle oſſer-<lb/>vazioni fiſiche non è mai dannevole lo <lb/>avere ſoverchia diligenza, vedranno che <lb/>non ho avuto torto a farlo.</s>
  <s xml:id="echoid-s361" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s362" xml:space="preserve">Quando facemmo l’ eſperienza era in-<lb/>tieramente ſereno il cielo, nè vento al-<lb/>cuno a quel che parvemi facevaſi a noi <lb/>d’intorno ſentire, quando pur non met-<lb/>taſi a conto un leggeriſſimo alito di <lb/>aria, che alle volte dalla banda di Mae-<lb/>ſtro ſentivamo, del che per altro ſcru-<lb/>poloſamente parlando potremmo ancor
<pb o="LXXXVIII" file="0096" n="96"/>
dubitare. </s>
  <s xml:id="echoid-s363" xml:space="preserve">I1 Barometro era a ventotto <lb/>dita ed una linea, ed il Termometro <lb/>di ſpirito di vino giuſta la diviſione del <lb/>Sig. </s>
  <s xml:id="echoid-s364" xml:space="preserve">di Reaumur, era a venti gradi ſopra <lb/>del ghiaccio.</s>
  <s xml:id="echoid-s365" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s366" xml:space="preserve">Altro più non reſtavaci a fare che <lb/>aſpettar l’inverno, per replicare in quel-<lb/>la ſtagione le noſtre oſſervazioni. </s>
  <s xml:id="echoid-s367" xml:space="preserve">Ven-<lb/>ne queſto adunque, e venne rigido a tal <lb/>ſegno, che quaſi ci pentimmo di averlo <lb/>deſiderato.</s>
  <s xml:id="echoid-s368" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s369" xml:space="preserve">La notte precedente i ſette di Febbrajo <lb/>dell’ anno 1741 fu la determinata da noi <lb/>per le noſtre eſperienze. </s>
  <s xml:id="echoid-s370" xml:space="preserve">Monſignor Mo-<lb/>linari colla ſolita gentilezza e bontà die-<lb/>de novamente gli ordini alla fortezza, <lb/>acciocchè alle tre della notte ſi ſparaſſero <lb/>altri quattro cannoni ſul baſtione mede-<lb/>deſimo ſu cui ſparati gli avevamo l’ <lb/>eſtate ſcorſa. </s>
  <s xml:id="echoid-s371" xml:space="preserve">Avendo mandato avanti <lb/>l’ orologio come ſopra ſi è detto già
<pb o="LXXXIX" file="0097" n="97"/>
rettiſicato, andammo la ſera al ſolito <lb/>Convento, il Sig. </s>
  <s xml:id="echoid-s372" xml:space="preserve">Euſtachio Zanotti il <lb/>Sig. </s>
  <s xml:id="echoid-s373" xml:space="preserve">Matteucci ed io, anzi il Sig. </s>
  <s xml:id="echoid-s374" xml:space="preserve">Con-<lb/>te Fulvio Bentivoglio Senatore ed ora <lb/>noſtro Ambaſciadore alla Corte di Ro-<lb/>ma, per l’ amore che porta alle Scien-<lb/>ze, e per la bontà che ha ſempre avu-<lb/>to per noi oſſervatori, volle venire con <lb/>noi, e con tutti i mezzi poſſibili ren-<lb/>derci più agevole il viaggio, e più <lb/>ſoffribile la rigidezza della ſtagione. </s>
  <s xml:id="echoid-s375" xml:space="preserve">Fu <lb/>preſente anche queſta volta la corona <lb/>medeſima dei Padri dell’ eſtate paſſata, <lb/>non meno di allora eloquenti e curioſi. <lb/></s>
  <s xml:id="echoid-s376" xml:space="preserve">Tenendo tutti noi gli occhi immobili <lb/>all’Occidente, vedemmo all’ora accorda-<lb/>ta il lampo del foco alla fortezza, nel <lb/>qual momento cominciammo a numerare <lb/>i ſecondi dell’ orologio. </s>
  <s xml:id="echoid-s377" xml:space="preserve">Queſti non fu-<lb/>rono già ſettantaſei come l’ anno avan-<lb/>ti, ma furono ſc<unsure/>ttantaotto, e mezzo
<pb o="XC" file="0098" n="98"/>
coſtantemente per tutte quattro le volte <lb/>che replicoſſi l’ eſperienza. </s>
  <s xml:id="echoid-s378" xml:space="preserve">Non era in <lb/>quella notte intieramente ſereno il Cie-<lb/>lo, imperiocchè quinci e quindi nubi ſtrac-<lb/>ciate, che data avevano poche ore a-<lb/>vanti neve, in parte lo ricoprivano. <lb/></s>
  <s xml:id="echoid-s379" xml:space="preserve">Spirava un Ponente alquanto forte, il <lb/>Barometro era all’ altezza di ventiſette <lb/>dita e ſei linee, ed il ſolito Termome-<lb/>tro era un grado e due decimi ſotto <lb/>del ghiaccio. </s>
  <s xml:id="echoid-s380" xml:space="preserve">Queſte due oſſervazioni <lb/>adunque che io le do per eſattiſſime, <lb/>dovrebbero farci credere eſſervi qualche <lb/>divario tra la velocità del ſuono nell’ <lb/>eſtate e nell’inverno.</s>
  <s xml:id="echoid-s381" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s382" xml:space="preserve">Io credeva già finite le mie eſperien-<lb/>ze almen per allora, quando l’ acciden-<lb/>te mi fornì il comodo per farne un’ al-<lb/>tra. </s>
  <s xml:id="echoid-s383" xml:space="preserve">Imperciocchè eſſendo io aſſai lieto <lb/>di avere trovata queſta allora inſperata <lb/>differenza, non voleva perdere alcuna oc-
<pb o="XCI" file="0099" n="99"/>
caſione per trovarne, o almen cercarne <lb/>delle altre. </s>
  <s xml:id="echoid-s384" xml:space="preserve">Avendo veduto eſſere dopo <lb/>cominciata una nebbia denſiſſima coſtan-<lb/>te per alcuni giorni verſo la ſera, de-<lb/>terminai di ſervirmene nell’uſo fiſico, e <lb/>di provare anche in queſta coſtituzione <lb/>di aria la celerità del ſuono. </s>
  <s xml:id="echoid-s385" xml:space="preserve">Ma non <lb/>era sì agevole queſta ſeconda eſperienza <lb/>come furono le prime, giacchè nella ce-<lb/>cità della nebbia denſiſsima non era poſ-<lb/>ſibile vedere il foco lontano tredici mi-<lb/>glia. </s>
  <s xml:id="echoid-s386" xml:space="preserve">Eccole il metodo di cui io mi <lb/>ſervij. </s>
  <s xml:id="echoid-s387" xml:space="preserve">Feci portare al conſueto Conven-<lb/>to la giornata dei dodici di Febbrajo, <lb/>che era talmente nebbioſa, che non di-<lb/>ſtingueanſi per modo alcuno gli oggetti <lb/>ne pure nella piccola diſtanza di dieci <lb/>o dodici piedi; </s>
  <s xml:id="echoid-s388" xml:space="preserve">feci portare dico il ſoli-<lb/>to orologio, ed un cannone aſſai groſ-<lb/>ſo, conceſſomi dalla bontà del Sig. </s>
  <s xml:id="echoid-s389" xml:space="preserve">Con-<lb/>te Filippo Aldrovandi, e del Sig. </s>
  <s xml:id="echoid-s390" xml:space="preserve">Mar-
<pb o="XCII" file="0100" n="100"/>
cheſe Paolo Magnani Senatori ampliſsi-<lb/>mi della noſtra Città, e grandiſsimi pro-<lb/>tettori degli ſtudj. </s>
  <s xml:id="echoid-s391" xml:space="preserve">Dopo di avere con-<lb/>certato il tutto col Sig. </s>
  <s xml:id="echoid-s392" xml:space="preserve">Euſtachio Za-<lb/>notti e col Sig. </s>
  <s xml:id="echoid-s393" xml:space="preserve">Matteucci, ſollecitamen-<lb/>te mi portai alla fortezza noſtra, dive-<lb/>nuta ormai un’Oſſervatorio di fiſica. </s>
  <s xml:id="echoid-s394" xml:space="preserve">Sa-<lb/>lirono intanto queſti il colle dell’ Oſſer-<lb/>vanza col Sig. </s>
  <s xml:id="echoid-s395" xml:space="preserve">Conte Fulvio Bentivoglio, <lb/>che non ozioſo ſpettatore, ma oſserva-<lb/>tore anch’egli diligentiſsimo eſser volle. <lb/></s>
  <s xml:id="echoid-s396" xml:space="preserve">All’ ora prima della notte eſsendo tutta-<lb/>via l’ aria più che mai nebbioſa, ſparoſ-<lb/>ſi al convento il cannone portatovi, <lb/>dal qual momento cominciaronſi a nu-<lb/>merare i ſecondi del pendolo. </s>
  <s xml:id="echoid-s397" xml:space="preserve">Giunto <lb/>immediatamente che ne fu il ſuono al-<lb/>la fortezza, dove io era coi bombardieri <lb/>tacitamente ad aſpettarlo, ſparoſſi ſubi-<lb/>to un’ altro cannone che là avevamo <lb/>già a queſt’ uopo preparato. </s>
  <s xml:id="echoid-s398" xml:space="preserve">Quelli che
<pb o="XCIII" file="0101" n="101"/>
ſopra il monte al Convento oſſervava-<lb/>no, e che già avevano incominciati a <lb/>contar i ſecondi dallo ſparo del lor Can-<lb/>none, proſeguendo a numerarli perſinchè <lb/>giugnea loro all’ orecchio lo ſtrepito di <lb/>quello che ad eſſi per così dire dalla for-<lb/>tezza riſpondea, li trovarono 157 eſat-<lb/>tiſſimamente per tutte le quattro volte <lb/>che replicoſſi in quella ſera lo ſparo. <lb/></s>
  <s xml:id="echoid-s399" xml:space="preserve">Ma come che alla fortezza non era poſ-<lb/>ſibile lo ſparare il cannone nell’ iſteſſo <lb/>iſtante che ſentivaſi il ſuono dello ſpa-<lb/>rato al convento, così biſognava tenere <lb/>pur conto di queſti momenti, che mal-<lb/>grado ogni diligenza non potevano non <lb/>isfuggirci. </s>
  <s xml:id="echoid-s400" xml:space="preserve">Di queſto appunto io mi era <lb/>incaricato, e tutte quattro le volte, tan-<lb/>ta fu la preſtezza di quei bombardieri, <lb/>non oltrepaſsò mai lo ſpazio di tre ſe-<lb/>condi. </s>
  <s xml:id="echoid-s401" xml:space="preserve">Era quietiſſima l’aria intieramen-<lb/>te, non ſentendoſi in alcuno di queſti
<pb o="XCIV" file="0102" n="102"/>
due luoghi vento alcuno, come oſſerva-<lb/>ſi nelle nebbie denſiſſime; </s>
  <s xml:id="echoid-s402" xml:space="preserve">era il Barome-<lb/>tro all’altezza di ventotto dita e quat-<lb/>tro linee, ed il Termometro al punto <lb/>del ghiaccio. </s>
  <s xml:id="echoid-s403" xml:space="preserve">Dal che ella vede adun-<lb/>que, che ſe alla ſomma di cinquantaſet-<lb/>te ſecondi ſottraggonſi i tre perduti nel <lb/>dar foco al cannone, ſi avrà la ſomma <lb/>del tempo ſpeſo dal ſuono nell’ andare <lb/>dal Convento alla Fortezza, e nel tor-<lb/>nare dalla Fortezza al Convento. </s>
  <s xml:id="echoid-s404" xml:space="preserve">E ſe <lb/>queſta ſomma divideſi in mezzo, avraſſi <lb/>il tempo ſpeſo nell’ andare dall’ uno all’ <lb/>altro di queſti due luoghi, la quale ſarà <lb/>di ſettantaſette ſecondi.</s>
  <s xml:id="echoid-s405" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s406" xml:space="preserve">Da queſto parrebbe che poteſſe inſe-<lb/>rirſi, che neſſuno o almen poco cangia-<lb/>mento nella propagazione del ſuono fa-<lb/>ceſſe la nebbia benchè denſiſſima, imper-<lb/>ciocchè gli è ben vero che il ſuono fu <lb/>più celere in queſta oſſervazione di un
<pb o="XCV" file="0103" n="103"/>
ſecondo e mezzo, ma gli è altresì vero, <lb/>che il freddo che era la ſera dei ſette, <lb/>era già diminuito ſenſibilmente.</s>
  <s xml:id="echoid-s407" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s408" xml:space="preserve">Eccole l’ iſtoria delle poche ricerche da <lb/>me fatte circa la propagazione del ſuo-<lb/>no. </s>
  <s xml:id="echoid-s409" xml:space="preserve">Ma non per queſto creda ella già <lb/>che voglia ancora far ſine a queſta mia <lb/>lettera. </s>
  <s xml:id="echoid-s410" xml:space="preserve">Voglio aver l’ onore di tratte-<lb/>nermi tuttavia un poco con lei, perchè <lb/>mi parrebbe di mancare al dover mio, <lb/>ſe non le diceſſi ancora quello che di <lb/>queſte ricerche io mi creda. </s>
  <s xml:id="echoid-s411" xml:space="preserve">Le aggiu-<lb/>gnerò adunque quelle riſleſſioni che mi <lb/>debbono mettere in ſalvo da quella tac-<lb/>cia, che ſe nol faceſſi taluno dar potreb-<lb/>bemi di troppo amante delle coſe mie.</s>
  <s xml:id="echoid-s412" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s413" xml:space="preserve">Io credo che di tutte le oſſervazioni <lb/>ſiſiche non ſiavene alcuna, che più di <lb/>queſta ſia diſſicile ad eſſere eſattamente <lb/>eſeguita, e in tal maniera che da eſſa <lb/>ſi poſſa concludere ſinalmente qualche
<pb o="XCVI" file="0104" n="104"/>
canone deciſivo. </s>
  <s xml:id="echoid-s414" xml:space="preserve">La diverſità che tro-<lb/>vaſi frà tutti gli eſperimenti che ſinora <lb/>ſonoſi fatti, parmi che ſervir poſſa di <lb/>contraſegno aſſai convincente a queſto <lb/>mio aſſerto. </s>
  <s xml:id="echoid-s415" xml:space="preserve">Imperciocchè chi vorrà di-<lb/>re che gli Accademici di Toſcana (non <lb/>parlo del Gaſſendo, perchè veramente e-<lb/>gli ſi è tanto da gli altri dilungato, che <lb/>non ſo trovare maniera di ſalvarlo) il <lb/>Perrault, il Caſſini vecchio, Piccard, <lb/>Romer, Huggen, Flamſted, Halley, Caſ-<lb/>ſini di Toury, e tanti altri che ci han-<lb/>no laſciate leggi più o meno l’una dall’ <lb/>altra diverſe, abbiano oſſervato negligen-<lb/>temente, e tutti ſieno caduti in errore? <lb/></s>
  <s xml:id="echoid-s416" xml:space="preserve">che deeſi adunque da queſto conclude-<lb/>re? </s>
  <s xml:id="echoid-s417" xml:space="preserve">che la velocità del ſuono non biſo-<lb/>gna che ſia eguale in ogni paeſe o in <lb/>ogni ſtagione, e che tante circoſtanze di-<lb/>verſamente combinate concorrano a can-<lb/>giarla, che non ſarà poſſibile ridurle mai
<pb o="XCVII" file="0105" n="105"/>
in pratica a legge coſtante. </s>
  <s xml:id="echoid-s418" xml:space="preserve">Quindi for-<lb/>ſe tante differenze anche in avvenire ſi <lb/>troveranno, quante ſaranno le oſſerva-<lb/>zioni che ſu queſto ai Fiſici dopo di <lb/>noi verrà in penſiero di fare. </s>
  <s xml:id="echoid-s419" xml:space="preserve">Ella abbia <lb/>la bontà di meco conſiderarne alcuna, <lb/>e vedrà che forſe non molto lunge dal <lb/>vero mi appongo.</s>
  <s xml:id="echoid-s420" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s421" xml:space="preserve">La velocità del ſuono eſſendo eguale <lb/>alla celerità dell’onde ſonore delle par-<lb/>ticelle dell’aria, anzi ben conſiderando-<lb/>la, non eſſendo il ſuono altro che una <lb/>ſucceſſiva comunicazione di moto per tut-<lb/>te le particelle di aria poſte d’intorno <lb/>al corpo ſonante, ne ſeguirà che qua-<lb/>lunque cauſa capace di alterare la cele-<lb/>rità di queſte onde ſonore, altererà al-<lb/>tresì la celerità del ſuono. </s>
  <s xml:id="echoid-s422" xml:space="preserve">Si moſtra nel-<lb/>la Fiſica, che l’ito e redito delle par-<lb/>ticelle elaſtiche dell’aria che muovonſi <lb/>nella legge degli archi di Cicloide, è
<pb o="XCVIII" file="0106" n="106"/>
più o meno veloce, giuſta la maggiore <lb/>o minore loro elaſticità. </s>
  <s xml:id="echoid-s423" xml:space="preserve">Ma queſta ela-<lb/>ſticità può moſtrarſi che ſta in ragione <lb/>della denſità, la quale ſtando in ragio-<lb/>ne del peſo dell’ atmosfera, farà che an-<lb/>che in ragione di lui ſtia l’ eleſticità. <lb/></s>
  <s xml:id="echoid-s424" xml:space="preserve">Tutte le coſe in conſeguenza che va-<lb/>rieranno, o il peſo dell’atmosfera, o qua-<lb/>lunque altra di queſte circoſtanze, che <lb/>continuamente certo da varie e differen-<lb/>ti cauſe eſterne ſi vanno cangiando, mu-<lb/>teranno ancora la celerità del ſuono. </s>
  <s xml:id="echoid-s425" xml:space="preserve"><lb/>A queſte anomalie dovrebbonſi aggiugner <lb/>quelle ancora che poſſono naſcere dai <lb/>corpi eſteri, che alle volte all’aria ſi uni-<lb/>ſcono, come ſono le eſalazioni ed altro, <lb/>delle quali chi potrà mai calcolar tutti <lb/>gli effetti? </s>
  <s xml:id="echoid-s426" xml:space="preserve">Ma ſe altri impedimenti non <lb/>vi foſſero che queſti a fare eſperienze <lb/>ſicure ſopra la velocità del ſuono, pa-<lb/>zienza; </s>
  <s xml:id="echoid-s427" xml:space="preserve">perchè almeno dal primo libere-
<pb o="XCIX" file="0107" n="107"/>
rebbeci il Barometro coll’indicarci il pe-<lb/>ſo dell’ atmosfera. </s>
  <s xml:id="echoid-s428" xml:space="preserve">La maggior diſſicoltà <lb/>conſiſte nelle irregolarità che naſcono <lb/>a cagione dei Venti, i quali ſpirando <lb/>movono più o meno l’ aria. </s>
  <s xml:id="echoid-s429" xml:space="preserve">Da qual-<lb/>che tempo in qua è vero ſi ſa, che i <lb/>venti che ſpirano o a ſeconda, o con-<lb/>tra il ſuono, accelerano o ritardano il <lb/>ſuo corſo; </s>
  <s xml:id="echoid-s430" xml:space="preserve">ma di quanto ſia queſto <lb/>cangiamento, neſſuno ancora ha potuto <lb/>determinare giuſtamente. </s>
  <s xml:id="echoid-s431" xml:space="preserve">Il Sig. </s>
  <s xml:id="echoid-s432" xml:space="preserve">Mariot-<lb/>te pretende, che il vento più veloce non <lb/>iſcorra che trentadue piedi in un ſecon-<lb/>do di tempo. </s>
  <s xml:id="echoid-s433" xml:space="preserve">Se queſto foſſe, ſcorrendo-<lb/>ne il ſuono mille e quaranta in circa, <lb/>parerebbe che poco diſturbo poteſſe te-<lb/>merſi dal vento, e tale, che non foſſe <lb/>per avventura poſſibile accorgerſene ſe <lb/>non in lunghiſſimi ſpazj. </s>
  <s xml:id="echoid-s434" xml:space="preserve">Ma le oſſerva-<lb/>zioni degli altri, e ſpecialmente del Der-<lb/>haam, benchè degne anch’ eſſe di lungo
<pb o="C" file="0108" n="108"/>
eſame, moſtrando eſſere aſſai veloci i ven-<lb/>ti, fanno crederci che più ſenſibile anco-<lb/>ra ſarà l’ impreſſione, o il cangiamento <lb/>che far debbono ſu la preſtezza del ſuo-<lb/>no. </s>
  <s xml:id="echoid-s435" xml:space="preserve">Ma come mai determinarlo? </s>
  <s xml:id="echoid-s436" xml:space="preserve">donde <lb/>abbiamo noi notizie ſuſſicienti per iſtabilire <lb/>qualche coſa di certo ſopra di loro? </s>
  <s xml:id="echoid-s437" xml:space="preserve">Tra <lb/>le oſſervazioni ſiſiche che hanno fatte <lb/>gli antichi, non ſo ſe alcuna ſiane più <lb/>coltivata di quelle dei venti: </s>
  <s xml:id="echoid-s438" xml:space="preserve">di eſſi parla <lb/>ſino Omero, alcune e varie coſe ne por-<lb/>ta Columella, Vitruvio, Strabone, Apu-<lb/>lejo, e moltiſſime Plinio, ſenza parla-<lb/>re della famoſa ottangola torre o caſa <lb/>dei venti, che tuttavia vedeſi a Atene <lb/>fabbricata dicono ſino da Andronico Ci-<lb/>reſte, intorno alla quale indicava con <lb/>una verga di ferro i venti che ſpirava-<lb/>no un volubile Tritone di bronzo, che <lb/>ſtava nella punta del tetto. </s>
  <s xml:id="echoid-s439" xml:space="preserve">E pure da <lb/>quel tempo ſino ad ora, malgrado le tan-
<pb o="CI" file="0109" n="109"/>
te diligenze dagli antichi e dai moder-<lb/>ni uſate, non ſi può determinare coſa <lb/>neſſuna di certo della lor velocità. </s>
  <s xml:id="echoid-s440" xml:space="preserve">Riſ-<lb/>petto agli antichi, pare che non ſia nè <lb/>pur loro paſſato per la mente di ricer-<lb/>carla, benchè abbiano ſino ſcoperto (chi <lb/>lo crederebbe?) </s>
  <s xml:id="echoid-s441" xml:space="preserve">eſſervi alcun vento che <lb/>ajuta la fecondità, o pure al dire di <lb/>Plinio, che fa pianger gli occhi alle pe-<lb/>core.</s>
  <s xml:id="echoid-s442" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s443" xml:space="preserve">Per potere adunque aſſodar qualche <lb/>coſa circa la velocità del ſuono, biſogne-<lb/>rebbe poter calcolare ancora tutte le al-<lb/>terazioni ch’ ei può ſoffrire dal vento, <lb/>non ſolo nel loco da dove ei parte e <lb/>in quello ove ſtaſſi ad oſſervare, ma an-<lb/>cora per tutto lo ſpazio che egli ſcor-<lb/>re tra l’ uno e l’ altro. </s>
  <s xml:id="echoid-s444" xml:space="preserve">Ora quale dei <lb/>Fiſici ci ha per anche determinato allor-<lb/>chè ſpira un vento, maſſime variabile <lb/>e incerto in un luogo, ſin dove poſſaſi
<pb o="CII" file="0110" n="110"/>
eſſo eſtendere? </s>
  <s xml:id="echoid-s445" xml:space="preserve">Il Sig. </s>
  <s xml:id="echoid-s446" xml:space="preserve">di Muschenbroek, <lb/>che più di ogni altro ci ha dato un ca-<lb/>pitolo aſſai diligente ſopra i venti nel <lb/>ſuo ſaggio di ſiſica, non ce ne fa ne pu-<lb/>re una parola: </s>
  <s xml:id="echoid-s447" xml:space="preserve">forſe che non gli ſarà nè <lb/>men paſſato per la mente. </s>
  <s xml:id="echoid-s448" xml:space="preserve">Ogni ragio-<lb/>ne ed ogni eſperienza ci inſegna, eſſere <lb/>probabiliſſimo che ſia queſta una gran-<lb/>diſſima confuſione per l’ aria. </s>
  <s xml:id="echoid-s449" xml:space="preserve">Vediamo <lb/>pure alle volte ſpirare un vento ad un’ <lb/>altezza in un luogo, mentre che nel me-<lb/>deſimo ſpirane un’altro oppoſto ad altra <lb/>altezza. </s>
  <s xml:id="echoid-s450" xml:space="preserve">Quindi veggonſi alle volte le <lb/>nubi più alte andare a Borea, nel tem-<lb/>po che le più baſſe ſono ſoſſiate all’ <lb/>Auſtro. </s>
  <s xml:id="echoid-s451" xml:space="preserve">L’ agitazione che vedeſi in un <lb/>lago di aqua ſe movonſi le onde impe-<lb/>tuoſamente, può farci argomentare qual-<lb/>che coſa di ſimile nell’ atmosfera. </s>
  <s xml:id="echoid-s452" xml:space="preserve">Le on-<lb/>de dirette ſi oppongono alle riſleſſe, e <lb/>naſcene una terza obbliqua nel mentre
<pb o="CIII" file="0111" n="111"/>
che in piccola diſtanza ve ne ſono dell’ <lb/>altre di oppoſta direzione. </s>
  <s xml:id="echoid-s453" xml:space="preserve">Nell’ aria ſuc-<lb/>cede l’iſteſſo, ed alle volte crederemo a <lb/>cagion di eſempio, che ſpiri un Greco <lb/>levante, quando non ſarà che un Oſtro <lb/>ed un Ponente, che ſi urtano con egual <lb/>forza inſieme. </s>
  <s xml:id="echoid-s454" xml:space="preserve">Non oſtante che vedeſi <lb/>andare il ſuono con eguale celerità a <lb/>diverſe altezze del Barometro, chi può <lb/>ſicuramente dire, come taluno benchè <lb/>diligentiſſimo oſſervatore ha detto, che <lb/>il differente peſo dell’ aria non muta pun-<lb/>to la celerità del ſuono, ſe non ſi fan-<lb/>no le eſperienze in diſtanze grandiſſime, <lb/>e non ſi computi ancora qualunque al-<lb/>terazione che nel viaggio può avere ſof-<lb/>ferta il ſuono dai varj venti che può <lb/>avere incontrato? </s>
  <s xml:id="echoid-s455" xml:space="preserve">Quando è mai quel <lb/>tempo in cui l’ aria non abbia alcun mo-<lb/>vimento?</s>
  <s xml:id="echoid-s456" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s457" xml:space="preserve">Da tutte queſte coſe ella può ben con-
<pb o="CIV" file="0112" n="112"/>
getturare, che io non ſono quì per pre-<lb/>tendere che le mie oſſervazioni ſieno <lb/>ſtate eſenti da queſti pericoli, che ſono <lb/>e ſaranno comuni a tutti gli oſſervato-<lb/>ri. </s>
  <s xml:id="echoid-s458" xml:space="preserve">Solamente le dirò, che fortunatamen-<lb/>te come ſopra le ho indicato, le due <lb/>ſere nelle quali feci l’ oſſervazione eſti-<lb/>va e l’ invernale (almeno ſul colle ove <lb/>eravamo noiad oſſervare) i venti non do-<lb/>vevano in modo alcuno diſturbare i no-<lb/>ſtri eſperimenti. </s>
  <s xml:id="echoid-s459" xml:space="preserve">Imperciocchè alla prima <lb/>oſſervazione, che diedeci il ſuono più <lb/>veloce della ſeconda, o non ſentivaſi <lb/>vento alcuno all’ intorno di noi, o ſe <lb/>ſentivaſi pure, era talmente dubbio e in <lb/>conſeguenza leggero, che neſſun ſenſibi-<lb/>le cangiamento avrebbe dovuto indurre <lb/>ſulla celerità del noſtro ſuono. </s>
  <s xml:id="echoid-s460" xml:space="preserve">Nella ſe-<lb/>conda ſpirava un forte Ponente il quale <lb/>doveva pur ſecondare il ſuono, che a <lb/>noi veniva poco dalla ſua direzione di-
<pb o="CV" file="0113" n="113"/>
ſtante, e pure ella ha veduto, che ci <lb/>venne più tardi. </s>
  <s xml:id="echoid-s461" xml:space="preserve">Replico che queſto era <lb/>il vento che ſpirava nel luogo in cui <lb/>oſſervavamo.</s>
  <s xml:id="echoid-s462" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s463" xml:space="preserve">Biſognerebbe cred’io per poter decidere <lb/>qualche coſa; </s>
  <s xml:id="echoid-s464" xml:space="preserve">poter fare le oſſervazioni <lb/>del ſuono in uno di quei paeſi ove il <lb/>vento è coſtante, per non temere che <lb/>gl’ intermedj poteſſero concorrere a di-<lb/>ſturbarle. </s>
  <s xml:id="echoid-s465" xml:space="preserve">Ma queſti per diſgrazia non <lb/>ſono che tra i Tropici e nei luoghi <lb/>giuſto ove tutto è mare, e dove certo <lb/>non ſaravvi mai alcuno oſſervatorio. <lb/></s>
  <s xml:id="echoid-s466" xml:space="preserve">Biſognerebbe altresì farle in luoghi aſſai <lb/>diſtanti, perchè nelle picciole lontanan-<lb/>ze come ſinora ſi è fatto, poco ſi ren-<lb/>dono ſenſibili le differenze ſe pur vi ſo-<lb/>no, e faciliſſimamente poſſono sfuggire <lb/>all’ orecchio il più attento, quand’ an-<lb/>che foſſe quello di quel felice oſſervato-<lb/>re, che aſſeriſce di avere udito in un gi-
<pb o="CVI" file="0114" n="114"/>
ardino l’ eco aſſai più tardo dell’ ordi-<lb/>nario, allo ſpirar di un vento oppoſto al <lb/>muro che il producea. </s>
  <s xml:id="echoid-s467" xml:space="preserve">Allora sì che <lb/>una ſola eſperienza o due potrebbero <lb/>metterci in chiaro della celerità non ſo-<lb/>lamente del ſuono, ma ancora di quel <lb/>vento che colà ſoſſia. </s>
  <s xml:id="echoid-s468" xml:space="preserve">Per darne un e-<lb/>ſempio, nel Mare del Meſſico ſpira quaſi <lb/>continuamente un vento di Levante. </s>
  <s xml:id="echoid-s469" xml:space="preserve">Se <lb/>nella punta dell’ Iſola Spagnuola che <lb/>guarda l’Occidente ſparaſſeſi un Canno-<lb/>ne, e ſe ne oſſervaſſe dalla Giamaica, <lb/>che non eſſendo lontana che centoven-<lb/>ti miglia italiane incirca nella ſteſſa la-<lb/>titudine, potrebbe in una notte oſcura <lb/>e quieta farſi comodiſſimamente, ſe ne <lb/>oſſervaſſe dico il rumore, avremmo il <lb/>tempo impiegato dal ſuono a ſcorrere <lb/>queſto conſiderabile tratto di aria, e <lb/>lo avremmo accelerato da quel vento <lb/>Lo avremmo dal medeſimo ritardato,
<pb o="CVII" file="0115" n="115"/>
ſe nella ſteſſa coſtituzione di aria ſi re-<lb/>plicaſſe l’ oſſervazione all’ oppoſto; </s>
  <s xml:id="echoid-s470" xml:space="preserve">e <lb/>con queſti due fatti ella vede, che po-<lb/>trebbeſi calcolare eſattamente la celeri-<lb/>tà almeno di quel vento che colà re-<lb/>gna, e quella del ſuono. </s>
  <s xml:id="echoid-s471" xml:space="preserve">Ma chi po-<lb/>trebbe poi aſſicurarſi che queſta eſſen-<lb/>do ſtata ſul mare, foſſe la medeſima <lb/>che ſtata ſarebbe in un luogo terreſtre? <lb/></s>
  <s xml:id="echoid-s472" xml:space="preserve">e chi pot<unsure/>rebbe eſſer certo, che gli aliti <lb/>marini non meritaſſero anch’ eſſi di eſſe-<lb/>re meſſi in conto?</s>
  <s xml:id="echoid-s473" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s474" xml:space="preserve">I Signori Halley, e Dampier, che <lb/>hanno viaggiato moltiſſimo ſu i Vaſcelli <lb/>d’Inghilterra, ci hanno dato molte belle <lb/>oſſervazioni circa i venti che ſpirano <lb/>regolarmente pei mari che hanno ſcor-<lb/>ſi, ma non hanno potuto oſſervar tut-<lb/>to. </s>
  <s xml:id="echoid-s475" xml:space="preserve">Chi ſa che i Signori Franceſi ſpe-<lb/>diti con tanta magniſicenza dal Re all’ <lb/>Indie occidentali ſolamenre per iſcoprir
<pb o="CVIII" file="0116" n="116"/>
la natura, non ci diano ancora qualche <lb/>notizia ſu queſto?</s>
  <s xml:id="echoid-s476" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s477" xml:space="preserve">Codeſte e varie altre riſleſſioni me-<lb/>no importanti che per brevità tralaſcio, <lb/>mi giuſtiſicheranno appo lei, ſe ho det-<lb/>to credere diſſiciliſſimo almeno per ora, <lb/>il potere determinare eſattiſſimamente la <lb/>velocità aſſoluta del ſuono in una co-<lb/>ſtante temperie di aria, e le alterazio-<lb/>ni, che nei moti e cangiamenti dell’ at-<lb/>mosfera eſſo poſſa ſoffrire.</s>
  <s xml:id="echoid-s478" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s479" xml:space="preserve">Colle mie oſſervazioni anch’ io avrei <lb/>potuto ſtabilire a un di preſſo la velo-<lb/>cità del ſuono in un dato tempo nella <lb/>noſtra Italia, e quindi paragonarla a <lb/>quella che determinarono i Fiorentini, <lb/>ed alle altre ſtabilite fuori d’Italia. </s>
  <s xml:id="echoid-s480" xml:space="preserve">Ma <lb/>per far queſto biſognava miſurare eſatta-<lb/>mente la diſtanza del colle ove oſſerva-<lb/>vamo dalla fortezza dove ſparavaſi, im-<lb/>preſa che troppa fatica importava. </s>
  <s xml:id="echoid-s481" xml:space="preserve">Il Sig
<pb o="CIX" file="0117" n="117"/>
Euſtachio Zanotti, che ha propoſto all’ <lb/>Accademia dell’Inſtituto un metodo per <lb/>determinare la ſigura della Terra, ricer-<lb/>ca che ai giorni noſtri ha intereſſato <lb/>tutto il Mondo ſiloſofo, effettuando il <lb/>ſuo progetto pieno di ingegnoſiſſime ri-<lb/>fleſſioni, potrebbe ſupplire a queſta mia <lb/>mancanza. </s>
  <s xml:id="echoid-s482" xml:space="preserve">Il metodo da lui propoſto <lb/>importa il miſurare un’arco di un para-<lb/>lello nella ſuperſicie della Terra, nella <lb/>qual miſura entra per l’appunto ancora <lb/>codeſta ricercata mia diſtanza.</s>
  <s xml:id="echoid-s483" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s484" xml:space="preserve">Io credo di averle dato in queſta mia <lb/>lettera, ſe non altro un’indizio almeno <lb/>della mia ſincerità, narrandole le oſſer-<lb/>vazioni che ho fatto, e dopo quaſi fa-<lb/>cendone io medeſimo la critica. </s>
  <s xml:id="echoid-s485" xml:space="preserve">Sareb-<lb/>be deſiderabile che molti Filoſoſi in tan-<lb/>te altre occaſioni aveſſero fatto il me-<lb/>deſimo, e così non ci avrebbero laſciato <lb/>tante oſſervazioni infedeli, overo ora-
<pb o="CX" file="0118" n="118"/>
toriamente ſcritte, voglio dire tacendo <lb/>quello che non fa per loro, ed aggiu-<lb/>gnendo peſo a tutto ciò che credevano <lb/>favorire i loro ſiſtemi. </s>
  <s xml:id="echoid-s486" xml:space="preserve">Oſſervazioni che <lb/>invece di ajutare i progreſſi della Fiſica, <lb/>non ſolo li ritardano, ma la involgono <lb/>di tali incertezze e contraddizioni, che <lb/>alle volte ci troviamo più all’oſcuro do-<lb/>po, che avanti di averle lette e con-<lb/>ſiderate. </s>
  <s xml:id="echoid-s487" xml:space="preserve">Le bacio divotamente le ma-<lb/>ni, e mi raccomando alla di lei ſtima-<lb/>tiſſima grazia, ed a quella del ſuo ſido <lb/>Acate, il gentiliſſimo Sig Seguier.</s>
  <s xml:id="echoid-s488" xml:space="preserve"/>
</p>
<pb file="0119" n="119"/>
</div>
<div xml:id="echoid-div10" type="section" level="1" n="9">
<head xml:id="echoid-head26" xml:space="preserve">NOI RIFORMATORI</head>
<head xml:id="echoid-head27" xml:space="preserve">Dello Studio di Padova.</head>
<p>
  <s xml:id="echoid-s489" xml:space="preserve">AVendo veduto per la Fede di Reviſione, ed Ap-<lb/>provazione del P. </s>
  <s xml:id="echoid-s490" xml:space="preserve">_Fra Paolo Tommaſo Manuelli_ <lb/>_Inquiſitore di Venezia_ nel Libro intitolato: </s>
  <s xml:id="echoid-s491" xml:space="preserve">_Delle Caraffe_ <lb/>_di Vetro, che ſcopiano al minimo sfreggio, che vi ſi faccia nel_ <lb/>_fondo &amp;</s>
  <s xml:id="echoid-s492" xml:space="preserve">c._ </s>
  <s xml:id="echoid-s493" xml:space="preserve">non v’eſſere coſa alcuna contro la Santa Fede Cat-<lb/>tolica; </s>
  <s xml:id="echoid-s494" xml:space="preserve">e parimente per Atteſtato del Segretario Noſtro, <lb/>niente contro Principi, e buoni coſtumi, concediamo <lb/>Licenza a _Simone Occhi Stampatore in Venezia,_ che poſ-<lb/>ſa eſſere ſtampato, oſſervando gli ordini in materia di <lb/>Stampe, e preſentando le ſolite copie alle Pubbliche Li-<lb/>brerie di Venezia, e di Padova.</s>
  <s xml:id="echoid-s495" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s496" xml:space="preserve">Data li 27. </s>
  <s xml:id="echoid-s497" xml:space="preserve">Maggio 1746.</s>
  <s xml:id="echoid-s498" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s499" xml:space="preserve">[Gio: </s>
  <s xml:id="echoid-s500" xml:space="preserve">Alviſe Mocenigo ſecondo Rif.</s>
  <s xml:id="echoid-s501" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s502" xml:space="preserve">[Giovanni Querini Proc. </s>
  <s xml:id="echoid-s503" xml:space="preserve">Rif.</s>
  <s xml:id="echoid-s504" xml:space="preserve"/>
</p>
<p>
  <s xml:id="echoid-s505" xml:space="preserve">[</s>
</p>
<p>
  <s xml:id="echoid-s506" xml:space="preserve">Regiſtrato in Libro a car. </s>
  <s xml:id="echoid-s507" xml:space="preserve">28. </s>
  <s xml:id="echoid-s508" xml:space="preserve">al n. </s>
  <s xml:id="echoid-s509" xml:space="preserve">25.</s>
  <s xml:id="echoid-s510" xml:space="preserve"/>
</p>
<p style="it">
  <s xml:id="echoid-s511" xml:space="preserve">Michiel Angelo Marini Seg.</s>
  <s xml:id="echoid-s512" xml:space="preserve"/>
</p>
<pb file="0120" n="120"/>
<pb file="0121" n="121"/>
<pb file="0121a" n="122"/>
  <figure>
    <image file="0121a-01" xlink:href="http://echo.mpiwg-berlin.mpg.de/zogilib?fn=/permanent/library/0347ZVRW/figures/0121a-01"/>
  </figure>
<pb file="0122" n="123"/>
<pb file="0123" n="124"/>
<pb file="0124" n="125"/>
  </div></text>
</echo>
author	Klaus Thoden <kthoden@mpiwg-berlin.mpg.de>
date	Wed, 29 Nov 2017 16:55:37 +0100
parents	22d6a63640c6
children