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DESpecs 2.0 Autumn 2009
author | Klaus Thoden <kthoden@mpiwg-berlin.mpg.de> |
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date | Thu, 02 May 2013 11:14:40 +0200 |
parents | 22d6a63640c6 |
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<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE archimedes SYSTEM "../dtd/archimedes.dtd"> <archimedes xmlns:xlink="http://www.w3.org/1999/xlink"> <info> <author>Commandino, Federico</author> <title>Liber de centro gravitatis solidorum</title> <date>1565</date> <place>Bologna</place> <translator/> <lang>la</lang> <cvs_file>comma_centr_023_la_1565.xml</cvs_file> <cvs_version/> <locator>023.xml</locator> </info> <text> <pb xlink:href="023/01/001.jpg"/> <front> <section> <p type="head"> <s id="s.000001">FEDERICI <lb/>COMMANDINI <lb/>VRBINATIS</s> <s id="s.000002">LIBER DE CENTRO <lb/>GRAVITATIS <lb/>SOLIDORVM.<!-- KEEP S--></s> </p> <figure id="id.023.01.001.1.jpg" xlink:href="023/01/001/1.jpg"/> <p type="head"> <s id="s.000003">CVM PRIVILEGIO IN ANNOS X.<!-- KEEP S--></s> </p> <p type="head"> <s id="s.000004">BONONIAE,<!-- KEEP S--></s> </p> <p type="head"> <s id="s.000005">Ex Officina Alexandri Benacii.<!-- KEEP S--></s> </p> <p type="head"> <s id="s.000006">MDLXV.<!-- KEEP S--></s> </p> <pb xlink:href="023/01/002.jpg"/> <pb xlink:href="023/01/003.jpg"/> </section> <section> <p type="head"> <s id="s.000007">ALEXANDRO FARNESIO <lb/> CARDINALI AMPLISSIMO. <lb/> ET OPTIMO.</s> </p> <p type="main"> <s id="s.000008">Cvm multæ res in mathematicis <lb/> di&longs;ciplinis nequaquam &longs;atis ad­<lb/> huc explicatæ &longs;int, tum perdif­<lb/> ficilis, & perob&longs;cura quæ&longs;tio <lb/> e&longs;t de centro grauitatis corpo­<lb/> rum &longs;olidorum; quæ, & ad co­<lb/> gno&longs;cendum pulcherrima e&longs;t, <lb/> & ad multa, quæ à mathematicis proponuntur, præ­<lb/> clare intelligenda maximum affert adiumentum. </s> <s id="s.000009">de <lb/> qua neminem ex mathematicis, neque no&longs;tra, neque <lb/> patrum no&longs;trorum memoria &longs;criptum reliqui&longs;&longs;e &longs;ci­<lb/> mus. </s> <s id="s.000010">& quamuis in earum monumentis literarum <expan abbr="nõ">non</expan> <lb/> nulla reperiantur, ex quibus in hanc &longs;ententiam addu<lb/> ci po&longs;&longs;umus, vt exi&longs;timemus hanc rem ab <expan abbr="ij&longs;d&etilde;">ij&longs;dem</expan> vber­<lb/> rime tractatam e&longs;&longs;e; tamen ne&longs;cio quo fato adhuc <lb/> in eiu&longs;modi librorum ignoratione ver&longs;amur. </s> <s id="s.000011">Archi­<lb/> medes quidem <expan abbr="mathematicorũ">mathematicorum</expan> princeps in libello, <lb/> cuius in&longs;criptio e&longs;t, <foreign lang="greek">ke/ntra ba/rwn e)pipe/dwn</foreign>, de centro pla­<lb/> norum copio&longs;i&longs;sime, atque acuti&longs;sime con&longs;crip&longs;it: & <lb/> in eo explicando <expan abbr="&longs;ummã">&longs;ummam</expan> ingenii, & &longs;cientiæ <expan abbr="gloriã">gloriam</expan> e&longs;t <lb/> <expan abbr="cõ&longs;ecutus">con&longs;ecutus</expan>. </s> <s id="s.000012">Sed de cognitione <expan abbr="c&etilde;tri">centri</expan> grauitatis <expan abbr="corporũ">corporum</expan> <lb/> <expan abbr="&longs;olidorũ">&longs;olidorum</expan> nulla in eius libris litera inuenitur. </s> <s id="s.000013">non mul<lb/> tos abhinc annos MARCELLVS II. PONT. MAX. <pb xlink:href="023/01/004.jpg"/>cum adhuc Cardinalis e&longs;&longs;et, mihi, quæ &longs;ua erat hu­<lb/> manitas, libros eiu&longs;dem Archimedis de ijs, quæ ve­<lb/> huntur in aqua, latine redditos dono dedit. </s> <s id="s.000014">hos cum <lb/>ego, ut aliorum &longs;tudia incitarem, <expan abbr="emendãdos">emendandos</expan>, & <expan abbr="cõ-mentariis">com­<lb/> mentariis</expan> illu&longs;trandos &longs;u&longs;cepi&longs;&longs;em, animaduerti dubi <lb/> tari non po&longs;&longs;e, quin Archimedes vel de hac materia <lb/> &longs;crip&longs;i&longs;&longs;et, vel aliorum mathematicorum &longs;cripta per­<lb/> legi&longs;&longs;et. </s> <s id="s.000015">nam in iis tum alia nonnulla, tum maxime <lb/> illam propo&longs;itionem, ut euidentem, & aliàs proba­<lb/> tam a&longs;&longs;umit, <expan abbr="Centrũ">Centrum</expan> grauitatis in portionibus conoi<lb/> dis rectanguli axem ita diuidere, vt pars, quæ ad verti<lb/> cem terminatur, alterius partis, quæ ad ba&longs;im dupla <lb/> &longs;it. </s> <s id="s.000016">Verum hæc ad eam partem mathematicarum <lb/> di&longs;ciplinarum præcipue refertur, in qua de centro <lb/> grauitatis corporum &longs;olidorum tractatur. </s> <s id="s.000017">non e&longs;t au<lb/> tem con&longs;entaneum Archimedem illum admirabilem <lb/> virum hanc propo&longs;itionem &longs;ibi argumentis con­<lb/> firmandam exi&longs;timaturum non fui&longs;&longs;e, ni&longs;i eam vel <lb/> aliis in locis probaui&longs;&longs;et, vel ab aliis probatam e&longs;&longs;e <lb/> comperi&longs;&longs;et. </s> <s id="s.000018">quamobrem nequid in iis libris intel­<lb/> ligendis de&longs;iderari po&longs;&longs;et, &longs;tatui hanc etiam partem <lb/> vel à veteribus prætermi&longs;&longs;am, vel tractatam quidem, <lb/> &longs;ed in tenebris iacentem, non intactam relinquere; <lb/> atque ex a&longs;sidua mathematicorum, præ&longs;ertim Archi­<lb/> medis lectione, quæ mihi in mentem venerunt, ea in <lb/> medium afferre; ut centri grauitatis corporum &longs;oli­<lb/> dorum, &longs;i non perfectam, at certe aliquam noti- <pb xlink:href="023/01/005.jpg"/>tiam haberemus. </s> <s id="s.000019">Quem meum laborem <expan abbr="nõ">non</expan> mathe­<lb/> maticis &longs;olum, verum iis etiam, qui naturæ ob&longs;curi­<lb/> tate delectantur, <expan abbr="nõ">non</expan> iniucundam fore &longs;peraui: multa <lb/> enim <foreign lang="greek">problh/mata</foreign> cognitione digni&longs;sima, quæ ad <expan abbr="vtrã-que">vtran­<lb/> que</expan> &longs;cientiam attinent, &longs;e&longs;e legentibus obtuli&longs;&longs;ent.</s> <lb/> <s id="s.000020">neque id vlli mirandum videri debet. </s> <s id="s.000021">vt enim in cor­<lb/>poribus no&longs;tris omnia membra, ex quibus certa quæ<lb/> dam officia na&longs;cuntur, diuino quodam ordine inter <lb/> &longs;e implicata, & colligata &longs;unt: in <expan abbr="iis&qacute;">iisque</expan>; admirabilis il­<lb/> la con&longs;piratio, quam <foreign lang="greek">su/mpnoian</foreign> græci vocant, eluce&longs;cit, <lb/> ita tres illæ Philo&longs;ophiæ (ut Ari&longs;totelis verbo vtar) <lb/> quæ veritatem &longs;olam propo&longs;itam habent, licet qui­<lb/> bu&longs;dam qua&longs;i finibus &longs;uis regantur: tamen <expan abbr="earũ">earum</expan> vna­<lb/> quæque per &longs;e ip&longs;am quodammodo imperfecta e&longs;t: <lb/> neque altera &longs;ine alterius auxilio plene comprehen­<lb/> di pote&longs;t. </s> <s id="s.000022">complures præterea mathematicorum no­<lb/> di ante hac explicatu difficillimi nullo negotio expe<lb/> diti e&longs;&longs;ent: atque (ut vno verbo complectar) ni&longs;i <lb/> mea valde amo, tractationem hanc meam &longs;tudio&longs;is <lb/> non mediocrem vtilitatem, & magnam volupta­<lb/> tem allaturam e&longs;&longs;e mihi per&longs;ua&longs;i. </s> <s id="s.000023">cum autem ad hoc <lb/> &longs;cribendum aggre&longs;&longs;us e&longs;sem, allatus e&longs;t ad me liber <lb/> Franci&longs;ci Maurolici Me&longs;&longs;anen&longs;is, in quo vir ille do­<lb/> cti&longs;simus, & in iis di&longs;ciplinis exercitati&longs;simus af­<lb/> firmabat &longs;e de centro grauitatis corporum &longs;olido­<lb/> rum con&longs;crip&longs;i&longs;&longs;e. </s> <s id="s.000024">cum hoc intellexi&longs;&longs;em, &longs;u&longs;tinui <lb/> me pauli&longs;per: tacitus que expectaui, dum opus cla- <pb xlink:href="023/01/006.jpg"/>ris&longs;imi uiri, quem &longs;emper honoris cau&longs;&longs;a nomino, <lb/> in lucem proferretur: mihi enim exploratis&longs;imum <lb/> erat: Franci&longs;cum Maurolicum multo doctius, & <lb/> exqui&longs;itius hoc di&longs;ciplinarum genus &longs;criptis &longs;uis tra<lb/> diturum. </s> <s id="s.000025">&longs;ed cum id tardius fieret, hoc e&longs;t, ut ego <lb/> interpretor, diligentius, mihi diutius hac &longs;criptione <lb/> non &longs;uper&longs;edendum e&longs;&longs;e duxi, præ&longs;ertim cum iam li­<lb/> bri Archimedis de iis, quæ uehuntur in aqua, opera <lb/> mea illu&longs;trati typis <expan abbr="excud&etilde;di">excudendi</expan> e&longs;&longs;ent. </s> <s id="s.000026">nec me alia cau&longs;<lb/> &longs;a impuli&longs;&longs;et, ut de centro grauitatis corporum &longs;oli­<lb/> dorum &longs;criberem, ni&longs;i ut hac etiam ratione lux eis <lb/> quàm maxime fieri po&longs;&longs;et afferretur. </s> <s id="s.000027"><expan abbr="atq;">atque</expan> id eò mihi <lb/> faciendum exi&longs;timaui, quòd in &longs;pem ueniebam fore, <lb/> ut cum ego ex omnibus mathematicis primus, hanc <lb/> materiam explicandam &longs;u&longs;cepi&longs;&longs;em; &longs;i quid errati for<lb/> te à me commi&longs;&longs;um e&longs;&longs;et, boni uiri potius id meæ de <lb/> &longs;tudio&longs;is hominibus bene <expan abbr="mer&etilde;di">merendi</expan> cupiditati, quàm <lb/> arrogantiæ a&longs;criberent. </s> <s id="s.000028">re&longs;tabat ut con&longs;iderarem, cui <lb/> potis&longs;imum ex principibus uiris contemplationem <lb/> hanc, nunc primum memoriæ, ac literis proditam de <lb/> dicarem. </s> <s id="s.000029">harum mearum cogitationum &longs;umma fa­<lb/> cta, exi&longs;timaui nemini conuenientius de centro graui <lb/> tatis corporum opus dicari oportere, quàm ALE­<lb/> XANDRO FARNESIO grauis&longs;imo, ac prudentis&longs;i­<lb/> mo Cardinali, quo in uiro &longs;umma fortuna &longs;emper <expan abbr="cũ">cum</expan> <lb/> &longs;umma uirtute certauit. </s> <s id="s.000030">quid enim maxime in te ad­<lb/> mirati debeant homines, ob&longs;curum e&longs;t; u&longs;um ne re- <pb xlink:href="023/01/007.jpg"/>rum, qui pueritiæ tempus extremum principium ha<lb/> bui&longs;ti, & <expan abbr="imperiorũ">imperiorum</expan>, & ad Reges, & Imperatores ho­<lb/> norificenti&longs;simarum legationum; an excellentiam <lb/> in omni genere literarum, qui vix <expan abbr="adole&longs;c&etilde;tulus">adole&longs;centulus</expan>, quæ <lb/> homines iam confirmata ætate &longs;ummo &longs;tudio, <expan abbr="diu-turnis&qacute;">diu­<lb/> turnisque</expan>; laboribus didicerunt, &longs;cientia, & cognitione <lb/> comprehendi&longs;ti: an con&longs;ilium, & &longs;apientiam in re­<lb/> gendis, & <expan abbr="gubernãdis">gubernandis</expan> Ciuitatibus, cuius graui&longs;simæ <lb/> &longs;ententiæ in &longs;ancti&longs;simo Reip. <!-- REMOVE S-->Chri&longs;tianæ con&longs;ilio di­<lb/> ctæ, potius diuina oracula, quàm &longs;ententiæ habitæ <lb/> &longs;unt, & habentur. </s> <s id="s.000031">prætermitto liberalitatem, & mu­<lb/> nificentiam tuam, quam in &longs;tudio&longs;i&longs;simo quoque ho<lb/> ne&longs;tando quotidie magis o&longs;tendis, ne videar auribus <lb/> tuis potius, quàm veritati &longs;eruire. </s> <s id="s.000032">quamuis à te in tot <lb/> præclaros viros tanta beneficia collata &longs;unt, & <expan abbr="confe-rũtur">confe­<lb/> runtur</expan>, vt omnibus te&longs;tatum &longs;it, nihil tibi e&longs;&longs;e charius, <lb/> nihil iucundius, quàm eximia tua liberalitate homi­<lb/> nes ad amplexandam virtutem, licet currentes incita­<lb/> re. </s> <s id="s.000033">nihil dico de ceteris virtutibus tuis, quæ tantæ <lb/> &longs;unt, quantæ ne cogitatione quidem comprehendi <lb/> po&longs;&longs;unt. </s> <s id="s.000034">Quamobrem hac præcipue de cau&longs;&longs;a te hu­<lb/> ius meæ lucubrationis patronum e&longs;&longs;e volui, quam ea, <lb/> qua &longs;oles, humanitate accipies. </s> <s id="s.000035">te enim &longs;emper ob <lb/> diuinas virtutes tuas colui, & ob&longs;eruaui: <expan abbr="nihil&qacute;">nihilque</expan>; mi­<lb/> hi fuit optatius; quàm tibi per&longs;pectum e&longs;&longs;e meum <lb/> erga te animum; <expan abbr="&longs;ingularem&qacute;">&longs;ingularemque</expan>; ob&longs;eruantiam. </s> <s id="s.000036">cœ­<lb/> lum igitur digito attingam, &longs;i po&longs;t graui&longs;simas oc- <pb xlink:href="023/01/008.jpg"/>cupationes tuas legendo Federici tui libro aliquid <lb/> impertiri temporis non grauaberis: <expan abbr="cum&qacute;">cumque</expan>; in iis, qui <lb/> tibi &longs;emper addicti erunt, numerare. </s> <s id="s.000037">Vale.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000038">Federicus Commandinus.</s> </p> </section> <section> <pb pagenum="1" xlink:href="023/01/009.jpg"/> <p type="head"> <s id="s.000039">FEDERICI COMMANDINI <lb/> VRBINATIS LIBER DE CENTRO <lb/> GRAVITATIS SOLIDORVM.</s> </p> </section> </front> <body> <chap> <p type="head"> <s id="s.000040">DIFFINITIONES.</s> </p> <p type="main"> <s id="s.000041"><arrow.to.target n="marg1"/></s> </p> <p type="margin"> <s id="s.000042"><margin.target id="marg1"/>1</s> </p> <p type="main"> <s id="s.000043">Centrvm grauitatis, Pappus <lb/> Alexandrinus in octauo ma­<lb/> thematicarum collectionum <lb/> libro ita diffiniuit.</s> </p> <p type="main"> <s id="s.000044"><foreign lang="greek">le/gomen de/ ke/ntron ba/rous e(ka/stou sw/<lb/> matos e)=inai shme=ion ti kei/menon e)nto/s, a/f' <lb/> o(/u kat' e/poi/nian a\rtnqe/n to/ ba/ros n(mere=i<lb/> fero/menon, kai\ fula/ssei th/n e)c a)rxh=s qe/­<lb/> sin, o)u mh\ peritrepo/menon e)n th= fora=</foreign>. hoc e&longs;t,</s> </p> <p type="main"> <s id="s.000045">Dicimus autem centrum grauitatis uniu&longs;cu­<lb/> iu&longs;que corporis punctum quoddam intra po&longs;i­<lb/> tum, à quo &longs;i graue appen&longs;um mente concipia­<lb/> tur, dum fertur quie&longs;cit; & &longs;eruat eam, quam in <lb/> principio habebat po&longs;itionem: neque in ip&longs;a la­<lb/> tione circumuertitur.</s> </p> <p type="main"> <s id="s.000046">Po&longs;&longs;umus etiam hoc modo diffinire.</s> </p> <p type="main"> <s id="s.000047">Centrum grauitatis uniu&longs;cuiu&longs;que &longs;olidæ figu<lb/> ræ e&longs;t punctum illud intra po&longs;itum, circa quod <lb/> undique partes æqualium momentorum con&longs;i­<lb/> &longs;tunt. </s> <s id="s.000048">&longs;i enim per tale centrum ducatur planum <lb/> figuram quomodocunque &longs;ecans &longs;emper in par­ <pb xlink:href="023/01/010.jpg"/>tes æqueponderantes ip&longs;am diuidet.</s> </p> <p type="main"> <s id="s.000049"><arrow.to.target n="marg2"/></s> </p> <p type="margin"> <s id="s.000050"><margin.target id="marg2"/>2</s> </p> <p type="main"> <s id="s.000051">Pri&longs;matis, cylindri, & portionis cylindri axem <lb/> appello rectam lineam, quæ oppo&longs;itorum plano­<lb/> rum centra grauitatis coniungit.</s> </p> <p type="main"> <s id="s.000052"><arrow.to.target n="marg3"/></s> </p> <p type="margin"> <s id="s.000053"><margin.target id="marg3"/>3</s> </p> <p type="main"> <s id="s.000054">Pyramidis, coni, & portionis coni axem dico li <lb/> neam, quæ à uertice ad centrum grauitatis ba&longs;is <lb/> perducitur.</s> </p> <p type="main"> <s id="s.000055"><arrow.to.target n="marg4"/></s> </p> <p type="margin"> <s id="s.000056"><margin.target id="marg4"/>4</s> </p> <p type="main"> <s id="s.000057">Si pyramis, conus, portio coni, uel conoidis &longs;e­<lb/> cetur plano ba&longs;i æquidi&longs;tante, pars, quæ e&longs;t ad ba­<lb/> &longs;im, fru&longs;tum pyramidis, coni, portionis coni, uel <lb/> conoidis dicetur; quorum plana æquidi&longs;tantia, <lb/> quæ opponuntur &longs;imilia &longs;unt, & inæqualia: axes <lb/> uero &longs;unt axium figurarum partes, quæ in ip&longs;is <lb/> comprehenduntur.</s> </p> <p type="head"> <s id="s.000058">PETITIONES.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000059"><arrow.to.target n="marg5"/></s> </p> <p type="margin"> <s id="s.000060"><margin.target id="marg5"/>1</s> </p> <p type="main"> <s id="s.000061">Solidarum figurarum &longs;imilium centra grauita­<lb/> tis &longs;imiliter &longs;unt po&longs;ita.</s> </p> <p type="main"> <s id="s.000062"><arrow.to.target n="marg6"/></s> </p> <p type="margin"> <s id="s.000063"><margin.target id="marg6"/>2</s> </p> <p type="main"> <s id="s.000064">Solidis figuris &longs;imilibus, & æqualibus inter &longs;e <lb/> aptatis, centra quoque grauitatis ip&longs;arum inter &longs;e <lb/> aptata erunt.</s> </p> <p type="head"> <s id="s.000065">THEOREMA I. PROPOSITIO I.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000066">Omnis figuræ rectilineæ in circulo de&longs;criptæ, <lb/> quæ æqualibus lateribus, & angulis contine­<lb/> <pb pagenum="2" xlink:href="023/01/011.jpg"/>tur, centrum grauitatis e&longs;t idem, quod circuli cen<lb/> trum.</s> </p> <p type="main"> <s id="s.000067">Sit primo triangulum æquilaterum abc in circulo de­<lb/> &longs;criptum: & diui&longs;a ac bifariam in d, ducatur bd. <!-- KEEP S--></s> <s id="s.000068">erit in li­<lb/> nea bd centrum grauitatis <expan abbr="triãguli">trianguli</expan> abc, ex tertia decima <lb/> primi libri Archimedis de centro grauitatis planorum. </s> <s id="s.000069">Et <lb/> <figure id="id.023.01.011.1.jpg" xlink:href="023/01/011/1.jpg"/><lb/> quoniam linea ab e&longs;t æqualis <lb/> lineæ bc; & ad ip&longs;i dc; <expan abbr="e&longs;t&qacute;">e&longs;tque</expan>; <lb/> bd utrique communis: trian­<arrow.to.target n="marg7"/><lb/> gulum abd æquale erit trian<lb/> gulo cbd: & anguli angulis æ­<lb/> quales, qui æqualibus lateri­<lb/> <arrow.to.target n="marg8"/><lb/> bus &longs;ubtenduntur. </s> <s id="s.000071">ergo angu<lb/> li ad d <expan abbr="utriq;">utrique</expan> recti &longs;unt. </s> <s id="s.000072">quòd <lb/> cum linea bd &longs;ecet ae bifa­<lb/> <arrow.to.target n="marg9"/><lb/> riam, & ad angulos rectos; in <lb/> ip&longs;a bd e&longs;t centrum circuli. </s> <s id="s.000073"><lb/> quare in eadem bd linea erit <lb/> centrum grauitatis trianguli, & circuli centrum. </s> <s id="s.000074">Similiter <lb/> diui&longs;a ab bifariam in e, & ducta ce, o&longs;tendetur in ip&longs;a <expan abbr="utrũ">utrum</expan> <lb/> que centrum contineri. </s> <s id="s.000075">ergo ea erunt in puncto, in quo li­<lb/> neæ bd, ce conueniunt. </s> <s id="s.000076">trianguli igitur abc centrum gra<lb/> uitatis e&longs;t idem, quod circuli centrum.</s> </p> <p type="margin"> <s id="s.000077"><margin.target id="marg7"/>8. primi.</s> </p> <p type="margin"> <s id="s.000078"><margin.target id="marg8"/>13. primi.</s> </p> <p type="margin"> <s id="s.000079"><margin.target id="marg9"/>corol. pri<lb/> mæ tertii</s> </p> <figure id="id.023.01.011.2.jpg" xlink:href="023/01/011/2.jpg"/> <p type="main"> <s id="s.000080">Sit quadratum abcd in cir­<lb/> culo de&longs;criptum: & ducantur <lb/> ac, bd, quæ conueniant in e. </s> <s id="s.000081">er­<lb/> go punctum e e&longs;t centrum gra<lb/> uitatis quadrati, ex decima eiu&longs; <lb/> dem libri Archimedis. <!-- KEEP S--></s> <s id="s.000082">Sed cum <lb/> omnes anguli ad abcd recti <lb/> <arrow.to.target n="marg10"/><lb/> &longs;int; erit abc &longs;emicirculus: <lb/> <expan abbr="item&qacute;">itemque</expan>; bcd: & propterea li­<lb/> neæ ac, bd diametri circuli: <pb xlink:href="023/01/012.jpg"/>quæ quidem in centro conueniunt. </s> <s id="s.000083">idem igitur e&longs;t centrum <lb/> grauitatis quadrati, & circuli centrum.</s> </p> <p type="margin"> <s id="s.000084"><margin.target id="marg10"/>31. tertii.</s> </p> <p type="main"> <s id="s.000085">Sit pentagonum æquilaterum, & æquiangulum in circu­<lb/> <figure id="id.023.01.012.1.jpg" xlink:href="023/01/012/1.jpg"/><lb/> lo de&longs;criptum abcd e. </s> <s id="s.000086">& iun­<lb/> cta bd, <expan abbr="bifariam&qacute;">bifariamque</expan>; in f diui&longs;a, <lb/> ducatur cf, & producatur ad <lb/> circuli circumferentiam in g; <lb/> quæ lineam ae in h &longs;ecet: de­<lb/> inde iungantur ac, cc. <!-- KEEP S--></s> <s id="s.000087">Eodem <lb/> modo, quo &longs;upra demon&longs;tra­<lb/> bimus angulum bcf æqualem <lb/> e&longs;&longs;e. </s> <s id="s.000088">angulo dcf; & angulos <lb/> ad f utro&longs;que rectos: & idcir­<lb/>co lineam cfg per circuli cen<lb/> trum tran&longs;ire. </s> <s id="s.000089">Quoniam igi­<lb/> tur latera cb, ba, & cd, de æqualia &longs;unt; & æquales anguli <lb/> <arrow.to.target n="marg11"/><lb/> cba, cde: erit ba&longs;is ca ba&longs;i: ce, & angulus bca angulo <lb/> dce æqualis. </s> <s id="s.000090">ergo & reliquus ach, reliquo ech. </s> <s id="s.000091">e&longs;t au­<lb/> tem ch utrique triangulo ach, ech communis. </s> <s id="s.000092">quare <lb/> ba&longs;is ah æqualis e&longs;t ba&longs;i hc: & anguli, qui ad h recti: <expan abbr="&longs;unt&qacute;">&longs;untque</expan>; <lb/> <arrow.to.target n="marg12"/><lb/> recti, qui ad f. </s> <s id="s.000093">ergo lineæ ae, bd inter &longs;e &longs;e æquidi&longs;tant. </s> <lb/> <s id="s.000094">Itaque cum trapezij abde latera bd, ae æquidi&longs;tantia à li<lb/> nea fh bifariam diuidantur; centrum grauitatis ip&longs;ius erit <lb/> <arrow.to.target n="marg13"/><lb/> in linea fh, ex ultima eiu&longs;dem libri Archimedis. <!-- KEEP S--></s> <s id="s.000095">Sed trian­<lb/> guli bcd centrum grauitatis e&longs;t in linea cf. </s> <s id="s.000096">ergo in eadem <lb/> linea ch e&longs;t centrum grauitatis trapezij abde, & trian­<lb/> guli bcd: hoc e&longs;t pentagoni ip&longs;ius centrum: & centrum <lb/> circuli. </s> <s id="s.000097">Rur&longs;us &longs;i iuncta ad, <expan abbr="bifariam&qacute;">bifariamque</expan>; &longs;ecta in k, duca­<lb/> tur ekl: demon&longs;trabimus in ip&longs;a utrumque centrum in <lb/> e&longs;&longs;e. </s> <s id="s.000098">Sequitur ergo, ut punctum, in quo lineæ cg, el con­<lb/> ueniunt, idem &longs;it centrum circuli, & centrum grauitatis <lb/> pentagoni.</s> </p> <p type="margin"> <s id="s.000099"><margin.target id="marg11"/>4. Primi.<!-- KEEP S--></s> </p> <p type="margin"> <s id="s.000100"><margin.target id="marg12"/>28. primi.</s> </p> <p type="margin"> <s id="s.000101"><margin.target id="marg13"/>13. Archi­<lb/> medis.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000102">Sit hexagonum abcdef æquilaterum, & æquiangulum <lb/> in circulo de&longs;ignatum: <expan abbr="iungantur&qacute;">iunganturque</expan>; bd, ae: & bifariam &longs;e­ <pb pagenum="3" xlink:href="023/01/013.jpg"/>cta bd in g puncto, ducatur cg; & protrahatur ad circuli <lb/> u&longs;que circumferentiam; quæ &longs;ecet ae in h. </s> <s id="s.000103">Similiter conclu<lb/> demus cg per centrum circuli tran&longs;ire: & bifariam &longs;ecate <lb/> lineam ae; <expan abbr="item&qacute;">itemque</expan>; lineas bd, ae inter &longs;e æquidi&longs;tantes e&longs;&longs;e. <lb/> </s> <s id="s.000104">Cum igitur cg per centrum circuli tran&longs;eat; & ad <expan abbr="punctũ">punctum</expan> <lb/> f perueniat nece&longs;&longs;e e&longs;t: quòd cdef &longs;it dimidium circumfe<lb/> <figure id="id.023.01.013.1.jpg" xlink:href="023/01/013/1.jpg"/><lb/> <arrow.to.target n="marg14"/><lb/> rentiæ circuli. </s> <s id="s.000105">Quare in eadem <lb/> diametro cf erunt centra gra<lb/> uitatis triangulorum bcd, <lb/> afe, & quadrilateri abde, ex <lb/> quibus con&longs;tat hexagonum ab <lb/> cdef. </s> <s id="s.000106">per&longs;picuum e&longs;t igitur in <lb/> ip&longs;a cf e&longs;&longs;e circuli centrum, & <lb/> centrum grauitatis hexagoni. <lb/> </s> <s id="s.000107">Rur&longs;us ducta altera diametro <lb/> ad, ei&longs;dem rationibus o&longs;tende­<lb/> mus in ip&longs;a utrumque <expan abbr="c&etilde;trum">centrum</expan> <lb/> ine&longs;&longs;e. </s> <s id="s.000108">Centrum ergo grauita­<lb/> tis hexagoni, & centrum circuli idem erit.</s> </p> <p type="margin"> <s id="s.000109"><margin.target id="marg14"/>13 Archi<lb/> medis.</s> <lb/> <s id="s.000110">9. <expan abbr="eiusdetilde;">eiusdem</expan> <lb/> m</s> </p> <p type="main"> <s id="s.000111">Sit heptagonum abcdefg æquilaterum atque æquian<lb/> <figure id="id.023.01.013.2.jpg" xlink:href="023/01/013/2.jpg"/><lb/> gulum in circulo de&longs;criptum: <lb/> & iungantur ce, bf, ag: di­<lb/> ui&longs;a autem ce bifariam in <expan abbr="pũtco">pun<lb/> cto</expan> h: & iuncta dh produca­<lb/> tur in k. </s> <s id="s.000112">non aliter demon­<lb/> &longs;trabimus in linea dk e&longs;&longs;e cen<lb/> trum circuli, & centrum gra­<lb/> uitatis trianguli cde, & tra­<lb/> peziorum bcef, abfg, hoc <lb/> e&longs;t centrum totius heptago­<lb/> ni: & rur&longs;us eadem centra in <lb/> alia diametro cl &longs;imiliter du­<lb/> cta contineri. </s> <s id="s.000113">Quare & centrum grauitatis heptagoni, & <lb/> centrum circuli in idem punctum conueniunt. </s> <s id="s.000114">Eodem mo <pb xlink:href="023/01/014.jpg"/>do in reliquis figuris æquilateris, & æquiangulis, quæ in cir­<lb/> culo de&longs;cribuntur, probabimus <expan abbr="c&etilde;trum">centrum</expan> grauitatis earum, <lb/> & centrum circuli idem e&longs;&longs;e. </s> <s id="s.000115">quod quidem demon&longs;trare <lb/> oportebat.</s> </p> <p type="main"> <s id="s.000116">Ex quibus apparet cuiuslibet figuræ rectilineæ <lb/> in circulo plane de&longs;criptæ centrum grauitatis <expan abbr="id&etilde;">idem</expan> <lb/> e&longs;&longs;e, quod & circuli centrum.<lb/> <arrow.to.target n="marg15"/></s> </p> <p type="margin"> <s id="s.000117"><margin.target id="marg15"/><foreign lang="greek">gnwri/mws</foreign></s> </p> <p type="main"> <s id="s.000118">Figuram in circulo plane de&longs;criptam appella­<lb/> mus, cuiu&longs;modi e&longs;t ea, quæ in duodecimo elemen<lb/> torum libro, propo&longs;itione &longs;ecunda de&longs;cribitur. <lb/> </s> <s id="s.000119">ex æqualibus enim lateribus, & angulis con&longs;tare <lb/> per&longs;picuum e&longs;t.</s> </p> <p type="head"> <s id="s.000120">THEOREMA II, PROPOSITIO II.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000121">Omnis figuræ rectilineæ in ellip&longs;i plane de&longs;cri­<lb/> ptæ centrum grauitatis e&longs;t idem, quod ellip&longs;is <lb/> centrum.</s> </p> <p type="main"> <s id="s.000122">Quo modo figura rectilinea in ellip&longs;i plane de&longs;cribatur, <lb/> docuimus in commentarijs in quintam propo&longs;itionem li­<lb/> bri Archimedis de conoidibus, & &longs;phæroidibus.</s> </p> <p type="main"> <s id="s.000123">Sit ellip&longs;is abcd, cuius maior axis ac, minor bd: <expan abbr="iun-gantur&qacute;">iun­<lb/> ganturque</expan>; ab, bc, cd, da: & bifariam diuidantur in pun­<lb/> ctis efgh. </s> <s id="s.000124">à centro autem, quod &longs;it k ductæ lineæ ke, kf, <lb/> kg, kh u&longs;que ad &longs;ectionem in puncta lmno protrahan­<lb/> tur: & iungantur lm, mn, no, ol, ita ut ac &longs;ecet li­<lb/> neas lo, mn, in z<foreign lang="greek">f</foreign> punctis; & bd &longs;ecet lm, on in <foreign lang="greek">xy.</foreign><lb/> erunt lk, kn linea una, <expan abbr="item&qacute;ue">itemque</expan> linea una ip&longs;æ mk, ko: <lb/> & lineæ ba, cd æquidi&longs;tabunt lineæ mo: & bc, ad ip&longs;i <lb/> ln. </s> <s id="s.000125">rur&longs;us lo, mn axi bd æquidi&longs;tabunt: & lm, <pb pagenum="4" xlink:href="023/01/015.jpg"/>on ip&longs;i ac. <!-- KEEP S--></s> <s id="s.000126">Quoniam enim triangulorum abk, adk, latus <lb/> bk e&longs;t æquale lateri kd, & ak utrique commune; <expan abbr="anguli&qacute;">angulique</expan>; <lb/> <arrow.to.target n="marg16"/><lb/> ad k recti. </s> <s id="s.000127">ba&longs;is ab ba&longs;i ad; & reliqui anguli reliquis an­<lb/> gulis æquales erunt. </s> <s id="s.000128">eadem quoque ratione o&longs;tendetur bc <lb/> <figure id="id.023.01.015.1.jpg" xlink:href="023/01/015/1.jpg"/><lb/> æqualis cd; & ab ip&longs;i <lb/> bc. <!-- REMOVE S-->quare omnes ab, <lb/> bc, cd, da &longs;unt æqua­<lb/> les. </s> <s id="s.000129">& quoniam anguli <lb/> ad a æquales &longs;unt angu<lb/> lis ad c; erunt anguli b <lb/> ac, acd coalterni inter <lb/> &longs;e æquales; <expan abbr="item&qacute;">itemque</expan>; dac, <lb/> acb. </s> <s id="s.000130">ergo cd ip&longs;i ba; <lb/> & ad ip&longs;i bc æquidi­<lb/> &longs;tat. </s> <s id="s.000131">At uero cum lineæ <lb/> ab, cd inter &longs;e æquidi­<lb/> &longs;tantes bifariam &longs;ecen­<lb/>tur in punctis eg; erit li<lb/> nea lekgn diameter &longs;e<lb/> ctionis, & linea una, ex <lb/> demon&longs;tratis in uige&longs;i­<lb/> maoctaua &longs;ecundi coni <lb/> corum. </s> <s id="s.000132">Et eadem ratione linea una mfkho. </s> <s id="s.000133">Sunt <expan abbr="aut&etilde;">autem</expan> ad, <lb/> bc inter &longs;e &longs;e æquales, & æquidi&longs;tantes. </s> <s id="s.000134">quare & earum di­<lb/> <arrow.to.target n="marg17"/><lb/> midiæ ah, bf; <expan abbr="item&qacute;">itemque</expan>; hd, fe; & quæ ip&longs;as coniungunt rectæ <lb/> lineæ æquales, & æquidi&longs;tantes erunt. </s> <s id="s.000135"><expan abbr="æquidi&longs;tãt">æquidi&longs;tant</expan> igitur ba, <lb/> cd diametro mo: & pariter ad, bc ip&longs;i ln æquidi&longs;tare o­<lb/> &longs;tendemus. </s> <s id="s.000136">Si igitur <expan abbr="man&etilde;te">manente</expan> diametro ac intelligatur abc <lb/> portio ellip&longs;is ad portionem adc moueri, cum primum b <lb/> applicuerit ad d, <expan abbr="cõgruet">congruet</expan> tota portio toti portioni, <expan abbr="linea&qacute;">lineaque</expan>; <lb/> ba lineæ ad; & bc ip&longs;i cd congruet: punctum uero e ca­<lb/> det in h; f in g: & linea ke in lineam kh: & kf in kg. <!-- KEEP S--></s> <s id="s.000137">qua <lb/> re & el in ho, et fm in gn. </s> <s id="s.000138">At ip&longs;a lz in zo; et m<foreign lang="greek">f</foreign> in <foreign lang="greek">f</foreign>n <lb/> cadet. </s> <s id="s.000139">congruet igitur triangulum lkz triangulo okz: et <pb xlink:href="023/01/016.jpg"/>triangulum mk<foreign lang="greek">f</foreign> triangulo nk<foreign lang="greek">f.</foreign> ergo anguli lzk, ozk, <lb/> m <foreign lang="greek">f</foreign> k, n<foreign lang="greek">f</foreign>k æquales &longs;unt, ac recti. </s> <s id="s.000140">quòd cum etiam recti <lb/> <arrow.to.target n="marg18"/><lb/> &longs;int, qui ad k; æquidi&longs;tabunt lineæ lo, mn axi bd. <!-- KEEP S--></s> <s id="s.000141">& ita <lb/> demon&longs;trabuntur lm, on ip&longs;i ac æquidi&longs;tare. </s> <s id="s.000142">Rur&longs;us &longs;i <lb/>iungantur al, lb, bm, mc, cn, nd, do, oa: & bifariam di<lb/> uidantur: à centro autem k ad diui&longs;iones ductæ lineæ pro­<lb/> trahantur u&longs;que ad &longs;ectionem in puncta pqrstuxy: & po <lb/> &longs;tremo py, qx, ru, st, qr, ps, yt, xu coniungantur. </s> <s id="s.000143">Simili­<lb/> <figure id="id.023.01.016.1.jpg" xlink:href="023/01/016/1.jpg"/><lb/> ter o&longs;tendemus lineas <lb/> py, qx, ru, st axi bd æ­<lb/> quidi&longs;tantes e&longs;&longs;e: & qr, <lb/> ps, yt, xu æquidi&longs;tan­<lb/> tes ip&longs;i ac. <!-- KEEP S--></s> <s id="s.000144">Itaque dico <lb/> harum figurarum in el­<lb/> lip&longs;i de&longs;criptarum cen­<lb/> trum grauitatis e&longs;&longs;e <expan abbr="pũ-ctum">pun­<lb/> ctum</expan> k, idem quod & el<lb/> lip&longs;is centrum. </s> <s id="s.000145">quadri­<lb/> lateri enim abcd cen­<lb/> trum e&longs;t k, ex decima e­<lb/> iu&longs;dem libri Archime­<lb/> dis, quippe <expan abbr="cũ">cum</expan> in eo om<lb/> nes diametri <expan abbr="cõueniãt">conueniant</expan>. </s> <lb/> <s id="s.000146">Sed in figura albmcn <lb/> <arrow.to.target n="marg19"/><lb/> do, quoniam trianguli <lb/> alb centrum grauitatis <lb/> <arrow.to.target n="marg20"/><lb/> e&longs;t in linea le: <expan abbr="trapezij&qacute;">trapezijque</expan>; abmo centrum in linea ek: trape<lb/> zij omcd in kg: & trianguli cnd in ip&longs;a gn: erit magnitu<lb/> dinis ex his omnibus con&longs;tantis, uidelicet totius figuræ cen <lb/> trum grauitatis in linea ln: & ob eandem cau&longs;&longs;am in linea <lb/> om. </s> <s id="s.000147">e&longs;t enim trianguli aod centrum in linea oh: trapezij <lb/> alnd in hk: trapezij lbcn in kf: & trianguli bmc in fm. </s> <lb/> <s id="s.000148">cum ergo figuræ albmcndo centrum grauitatis &longs;it in li­<lb/> nea ln, & in linea om; erit centrum ip&longs;ius punctum k, in <pb pagenum="5" xlink:href="023/01/017.jpg"/>quo &longs;cilicet ln, om conueniunt. </s> <s id="s.000149">Po&longs;tremo in figura <lb/> aplqbrmsctnudxoy centrum grauitatis trian<lb/> guli pay, & trapezii ploy e&longs;t in linea az: trapeziorum <lb/> uero lqxo, qbdx centrum e&longs;t in linea zk: & <expan abbr="trapeziorũ">trapeziorum</expan> <lb/> brud, rmnu in k<foreign lang="greek">f:</foreign> & denique trapezii mstn; & triangu<lb/> li sct in <foreign lang="greek">f</foreign>c. </s> <s id="s.000150">quare magnitudinis ex his compo&longs;itæ <expan abbr="centrũ">centrum</expan> <lb/> in linea ac con&longs;i&longs;tit. </s> <s id="s.000151">Rur&longs;us trianguli qbr, & trapezii ql<lb/> mr centrum e&longs;t in linea b<foreign lang="greek">x.</foreign> trapeziorum lpsm, pacs, <lb/> aytc, yont in linea <foreign lang="greek">xf:</foreign> <expan abbr="trapeziiq;">trapeziique</expan> oxun, & trianguli <lb/> xdu centrum in <foreign lang="greek">y</foreign>d. <!-- KEEP S--></s> <s id="s.000152">totius ergo magnitudinis centrum <lb/> e&longs;t in linea bd. <!-- KEEP S--></s> <s id="s.000153">ex quo &longs;equitur, centrum grauitatis figuræ <lb/> aplqbrmsctnudxoy e&longs;&longs;e <expan abbr="punctũ">punctum</expan> K, lineis &longs;cilicet ac, <lb/> bd commune, quæ omnia demon&longs;trare oportebat.</s> </p> <p type="margin"> <s id="s.000154"><margin.target id="marg16"/>8. primi</s> </p> <p type="margin"> <s id="s.000155"><margin.target id="marg17"/>33. primi</s> </p> <p type="margin"> <s id="s.000156"><margin.target id="marg18"/>28. primi.</s> </p> <p type="margin"> <s id="s.000157"><margin.target id="marg19"/>13. Archi<lb/> medis.</s> </p> <p type="margin"> <s id="s.000158"><margin.target id="marg20"/>Vltima.<!-- KEEP S--></s> </p> <p type="head"> <s id="s.000159">THEOREMA III. PROPOSITIO III.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000160">Cuiuslibet portio­<lb/> nis circuli, & ellip&longs;is, <lb/> quæ dimidia non &longs;it <lb/> maior, centrum graui <lb/> tatis in portionis dia­<lb/> metro con&longs;i&longs;tit.</s> </p> <figure id="id.023.01.017.1.jpg" xlink:href="023/01/017/1.jpg"/> <p type="main"> <s id="s.000161">HOC eodem pror&longs;us <lb/> modo demon&longs;trabitur, <lb/> quo in libro de centro gra<lb/> uitatis planorum ab Ar­<lb/> chimede <expan abbr="demon&longs;tratũ">demon&longs;tratum</expan> e&longs;t, <lb/> in portione <expan abbr="cõtenta">contenta</expan> recta <lb/> linea, & rectanguli coni &longs;e<lb/> ctione grauitatis <expan abbr="c&etilde;trum">centrum</expan> <lb/> e&longs;&longs;e in diametro portio­<lb/> nis. </s> <s id="s.000162">Et ita demon&longs;trari po<lb/> <pb xlink:href="023/01/018.jpg"/>te&longs;t in portione, quæ recta linea & obtu&longs;ianguli coni &longs;e­<lb/> ctione, &longs;eu hyperbola continetur.</s> </p> <p type="head"> <s id="s.000163">THEOREMA IIII. PROPOSITIO IIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000164">IN circulo & ellip&longs;i idem e&longs;t figuræ & graui­<lb/> tatis centrum.</s> </p> <p type="main"> <s id="s.000165">SIT circulus, uel ellip&longs;is, cuius centrum a. </s> <s id="s.000166">Dico a gra­<lb/> uitatis quoque centrum e&longs;&longs;e. </s> <s id="s.000167">Si enim fieri pote&longs;t, &longs;it b cen­<lb/> trum grauitatis: & iuncta ab extra figuram in c produca<lb/> tur: quam uero proportionem habet linea ca ad ab, ha­<lb/> beat circulus a ad alium circulum, in quo d; uel ellip&longs;is ad <lb/> aliam ellip&longs;im: & in circulo, uel ellip&longs;i figura rectilinea pla­<lb/> ne de&longs;cribatur adco, ut tandem relinquantur portiones <lb/> quædam minores circulo, uel ellip&longs;i d; quæ figura &longs;it abcefg<lb/> hklmn. </s> <s id="s.000168">Illud uero in circulo fieri po&longs;&longs;e ex duodecimo <lb/> elementorum libro, propo&longs;itione &longs;ecunda manife&longs;te con­<lb/> <figure id="id.023.01.018.1.jpg" xlink:href="023/01/018/1.jpg"/><lb/> &longs;tat; at in ellip&longs;i nos demon&longs;tra­<lb/> uimus in commentariis in quin­<lb/> tam propo&longs;itionem Archimedis <lb/> de conoidibus, & &longs;phæroidibus. </s> <lb/> <s id="s.000169">erit igitur a centrum grauitatis <lb/> ip&longs;ius figuræ, quod proxime <expan abbr="o&longs;t&etilde;">o&longs;ten</expan><lb/> dimus. </s> <s id="s.000170">Itaque quoniam circulus <lb/> a ad circulum d, uel ellip&longs;is a ad <lb/> ellip&longs;im d eandem <expan abbr="proportion&etilde;">proportionem</expan> <lb/> habet, quam linea ca ad ab: <lb/> portiones uero &longs;unt minores cir<lb/> <arrow.to.target n="marg21"/><lb/> culo uel ellip&longs;i d: habebit circu­<lb/> lus, uel ellip&longs;is ad portiones ma­<lb/> iorem proportionem, quàm ca <lb/> <arrow.to.target n="marg22"/><lb/> ad ab: & diuidendo figura recti­<lb/> linea abcefghklmn ad portiones <pb pagenum="6" xlink:href="023/01/019.jpg"/><figure id="id.023.01.019.1.jpg" xlink:href="023/01/019/1.jpg"/><lb/> habebit maiorem <expan abbr="proportion&etilde;">proportionem</expan>, <lb/> quam cb ad ba. </s> <s id="s.000171">fiat ob ad ba, <lb/> ut figura rectilinea ad portio­<lb/> nes. </s> <s id="s.000172">cum igitur à circulo, uel el­<lb/> lip&longs;i, cuius grauitatis centrum <lb/> e&longs;t b, auferatur figura rectilinea <lb/> efghklmn, cuius centrum a; <lb/> reliquæ magnitudinis ex portio<lb/> <arrow.to.target n="marg23"/><lb/> nibus compo&longs;itæ centrum graui<lb/> tatis erit in linea ab producta, <lb/> & in puncto o, extra figuram po<lb/> &longs;ito. </s> <s id="s.000173">quod quidem fieri nullo mo<lb/> do po&longs;&longs;e per&longs;picuum e&longs;t. </s> <s id="s.000174">&longs;equi­<lb/> tur ergo, ut circuli & ellip&longs;is cen<lb/> trum grauitatis &longs;it punctum a, <lb/> idem quod figuræ centrum.</s> </p> <p type="margin"> <s id="s.000175"><margin.target id="marg21"/>8. quinti</s> </p> <p type="margin"> <s id="s.000176"><margin.target id="marg22"/>19. quinti <lb/> apud <expan abbr="Cãpanum">Cam<lb/> panum</expan> .</s> </p> <p type="margin"> <s id="s.000177"><margin.target id="marg23"/>8. Archi­<lb/> medis.</s> </p> <p type="head"> <s id="s.000178">ALITER.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000179">Sit circulus, uel ellip&longs;is abcd, <lb/> cuius diameter db, & centrum e: <expan abbr="ducaturq;">ducaturque</expan> per e recta li<lb/> nea ac, &longs;ecans ip&longs;am db ad rectos angulos. </s> <s id="s.000180">erunt adc, <lb/> abc circuli, uel ellip&longs;is dimidiæ portiones. </s> <s id="s.000181">Itaque quo­<lb/> <figure id="id.023.01.019.2.jpg" xlink:href="023/01/019/2.jpg"/><lb/> niam por<lb/> <expan abbr="tiõis">tionis</expan> adc <lb/> <expan abbr="c&etilde;trũ">centrum</expan> gra­<lb/> uitatis e&longs;t <lb/> in diame­<lb/> tro de: & <lb/> portionis <lb/> abc cen­<lb/> trum e&longs;t <expan abbr="ĩ">im</expan> <lb/> ip&longs;a eb: to<lb/> tius circu<lb/> li, uel ellip&longs;is grauitatis centrum erit in diametro db. </s> <lb/> <s id="s.000182">Sit autem portionis adc <expan abbr="c&etilde;trum">centrum</expan> grauitatis f: & &longs;umatur <pb xlink:href="023/01/020.jpg"/>in linea eb <expan abbr="punctũ">punctum</expan> g, ita ut fit ge æqualis ef. </s> <s id="s.000183">erit g por­<lb/> tionis abc centrum. </s> <s id="s.000184">nam &longs;i hæ portiones, quæ æquales <lb/> & &longs;imiles &longs;unt, inter &longs;e &longs;e aptentur, ita ut be cadat in de, <lb/> & punctum b in d cadet, & g in f: figuris autem æquali­<lb/> bus, & &longs;imilibus inter &longs;e aptatis, centra quoque grauitatis <lb/> ip&longs;arum inter &longs;e aptata erunt, ex quinta petitione Archi­<lb/> medis in libro de centro grauitatis planorum. </s> <s id="s.000185">Quare cum <lb/> portionis adc centrum grauitatis &longs;it f: & portionis <lb/> abc centrum g: magnitudinis; quæ ex utri&longs;que efficitur: <lb/> hoc e&longs;t circuli uel ellip&longs;is grauitatis centrum in medio li­<lb/> neæ fg, quod e&longs;t e, con&longs;i&longs;tet, ex quarta propo&longs;itione eiu&longs;­<lb/> dem libri Archimedis. <!-- KEEP S--></s> <s id="s.000186">ergo circuli, uel ellip&longs;is centrum <lb/> grauitatis e&longs;t idem, quod figuræ centrum. </s> <s id="s.000187">atque illud e&longs;t, <lb/> quod demon&longs;trare oportebat.</s> </p> <p type="main"> <s id="s.000188">Ex quibus &longs;equitur portionis circuli, uel ellip­<lb/> &longs;is, quæ dimidia maior &longs;it, centrum grauitatis in <lb/> diametro quoque ip&longs;ius con&longs;i&longs;tere.</s> </p> <figure id="id.023.01.020.1.jpg" xlink:href="023/01/020/1.jpg"/> <p type="main"> <s id="s.000189">Sit enim maior portio abc, cu<emph type="italics"/>i<emph.end type="italics"/>us diameter bd, & com­<lb/> pleatur circulus, uel ellip&longs;is, ut portio reliqua fit aec, dia <pb pagenum="7" xlink:href="023/01/021.jpg"/>metrum habens ed. <!-- KEEP S--></s> <s id="s.000190">Quoniam igitur circuli uel ellip&longs;is <lb/> aecb grauitatis centrum e&longs;t in diametro be, & portio­<lb/> nis aec centrum in linea ed: reliquæ portionis, uidelicet <lb/> abc centrum grauitatis in ip&longs;a bd con&longs;i&longs;tat nece&longs;&longs;e e&longs;t, ex <lb/> octaua propo&longs;itione eiu&longs;dem.</s> </p> <p type="head"> <s id="s.000191">THEOREMA V. PROPOSITIO V.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000192">SI pri&longs;ma &longs;ecetur plano oppo&longs;itis planis æqui <lb/> di&longs;tante, &longs;ectio erit figura æqualis & &longs;imilis ei, <lb/> quæ e&longs;t oppo&longs;itorum planorum, centrum graui<lb/> tatis in axe habens.</s> </p> <p type="main"> <s id="s.000193">Sit pri&longs;ma, in quo plana oppo&longs;ita &longs;int triangula abc, <lb/> def; axis gh: & &longs;ecetur plano iam dictis planis <expan abbr="æquidi&longs;tã">æquidi&longs;tan</expan><lb/> te; quod faciat &longs;ectionem klm; & axi in <expan abbr="pũcto">puncto</expan> n occurrat. </s> <lb/> <s id="s.000194">Dico klm triangulum æquale e&longs;&longs;e, & &longs;imile triangulis abc <lb/> def; atque eius grauitatis centrum e&longs;&longs;e punctum n. </s> <s id="s.000195">Quo­<lb/> <figure id="id.023.01.021.1.jpg" xlink:href="023/01/021/1.jpg"/><lb/> niam enim plana abc <lb/> Klm æquidi&longs;tantia <expan abbr="&longs;ecã">&longs;ecan</expan><lb/> <arrow.to.target n="marg24"/><lb/> tur a plano ae; rectæ li­<lb/> neæ ab, Kl, quæ &longs;unt ip <lb/> &longs;orum <expan abbr="cõmunes">communes</expan> &longs;ectio­<lb/> nes inter &longs;e &longs;e æquidi­<lb/> &longs;tant. </s> <s id="s.000196">Sed æquidi&longs;tant <lb/> ad, be; cum ae &longs;it para<lb/> lelogrammum, ex pri&longs;­<lb/> matis diffinitione. </s> <s id="s.000197">ergo <lb/> & al <expan abbr="parallelogrammũ">parallelogrammum</expan> <lb/> erit; & propterea linea <lb/> <arrow.to.target n="marg25"/><lb/> kl, ip&longs;i ab æqualis. </s> <s id="s.000198">Si­<lb/> militer demon&longs;trabitur <lb/> lm æquidi&longs;tans, & æqua <lb/> lis bc; & mk ip&longs;i ca.</s> <pb xlink:href="023/01/022.jpg"/> <s id="s.000199">Itaque quoniam duæ lineæ Kl, lm &longs;e &longs;e tangentes, duabus <lb/> lineis &longs;e &longs;e tangentibus ab, bc æquidi&longs;tant; nec &longs;unt in e o­<lb/> dem plano: angulus klm æqualis e&longs;t angulo abc: & ita an<lb/> <arrow.to.target n="marg26"/><lb/> gulus lmk, angulo bca, & mkl ip&longs;i cab æqualis probabi<lb/> tur. </s> <s id="s.000200">triangulum ergo klm e&longs;t æquale, & &longs;imile triangulo <lb/> abc. quare & triangulo def. </s> <s id="s.000201">Ducatur linea cgo, & per ip<lb/> &longs;am, & per cf ducatur planum &longs;ecans pri&longs;ma; cuius & paral<lb/> lelogrammi ae communis &longs;ectio &longs;it opq.</s> <s id="s.000202"> tran&longs;ibit linea <lb/> fq per h, & mp per n. </s> <s id="s.000203">nam cum plana æquidi&longs;tantia &longs;ecen <lb/> tur à plano cq, communes eorum &longs;ectiones cgo, mp, fq <lb/> &longs;ibi ip&longs;is æquidi&longs;tabunt. </s> <s id="s.000204">Sed & æquidi&longs;tant ab, kl, de. </s> <s id="s.000205">an­<lb/> <arrow.to.target n="marg27"/><lb/> guli ergo aoc, kpm, dqf inter &longs;e æquales &longs;unt: & &longs;unt <lb/> æquales qui ad puncta akd con&longs;tituuntur. </s> <s id="s.000206">quare & reliqui <lb/> reliquis æquales; & triangula aco, Kmp, dfq inter &longs;e &longs;imi <lb/> <arrow.to.target n="marg28"/><lb/> lia erunt. </s> <s id="s.000207">Vt igitur ca ad ao, ita fd ad dq: & permutando <lb/> ut ca ad fd, ita ao ad dq.</s> <s id="s.000208">e&longs;t autem ca æqualis fd. <!-- KEEP S--></s> <s id="s.000209">ergo & <lb/> ao ip&longs;i dq.</s> <s id="s.000210"> eadem quoque ratione & ao ip&longs;i Kp æqualis <lb/> demon&longs;trabitur. </s> <s id="s.000211">Itaque &longs;i triangula, abc, def æqualia & <lb/> <figure id="id.023.01.022.1.jpg" xlink:href="023/01/022/1.jpg"/><lb/> &longs;imilia inter &longs;e <expan abbr="apt&etilde;tur">aptentur</expan>, <lb/> cadet linea fq in lineam <lb/> <arrow.to.target n="marg29"/><lb/> cgo. </s> <s id="s.000212">Sed & <expan abbr="centrũ">centrum</expan> gra<lb/> uitatis h in g <expan abbr="centrũ">centrum</expan> ca­<lb/> det. </s> <s id="s.000213"><expan abbr="trã&longs;ibit">tran&longs;ibit</expan> igitur linea <lb/> fq per h: & planum per <lb/> co & cf <expan abbr="ductũ">ductum</expan> per <expan abbr="ax&etilde;">axem</expan> <lb/> gh ducetur: <expan abbr="idcircoq;">idcircoque</expan> li <lb/> neam mp <expan abbr="etiã">etiam</expan> per n <expan abbr="trã">tran</expan><lb/> &longs;ire nece&longs;&longs;e erit. </s> <s id="s.000214">Quo­<lb/> niam ergo fh, cg æqua­<lb/> les &longs;unt, & <expan abbr="æquidi&longs;tãtes">æquidi&longs;tantes</expan>: <lb/> <expan abbr="itemq;">itemque</expan> hq, go; rectæ li­<lb/> neæ, quæ ip&longs;as <expan abbr="cõnectũt">connectunt</expan> <lb/> cmf, gnh, opq æqua­<lb/> les æquidi&longs;tantes <expan abbr="erũt">erunt</expan>.</s> <pb pagenum="8" xlink:href="023/01/023.jpg"/> <s id="s.000215">æquidi&longs;tant autem cgo, mnp. </s> <s id="s.000216">ergo <expan abbr="parallelogrãma">parallelogramma</expan> &longs;unt <lb/> on, gm, & linea mn æqualis cg; & np ip&longs;i go. </s> <s id="s.000217">aptatis igi­<lb/> tur klm, abc <expan abbr="triãgulis">triangulis</expan>, quæ æqualia & &longs;imilia <expan abbr="sũt">sunt</expan>; linea mp <lb/> in co, & punctum n in g cadet. </s> <s id="s.000218">Quòd <expan abbr="cũ">cum</expan> g &longs;it centrum gra­<lb/> uitatis trianguli abc, & n trianguli klm grauitatis cen­<lb/> trum erit id, quod demon&longs;trandum relinquebatur. </s> <s id="s.000219">Simili <lb/> ratione idem contingere demon&longs;trabimus in aliis pri&longs;ma­<lb/> tibus, &longs;iue quadrilatera, &longs;iue plurilatera habeant plana, <lb/> quæ opponuntur.</s> </p> <p type="margin"> <s id="s.000220"><margin.target id="marg24"/>16. unde­<lb/> cimi</s> </p> <p type="margin"> <s id="s.000221"><margin.target id="marg25"/>34. primi</s> </p> <p type="margin"> <s id="s.000222"><margin.target id="marg26"/>10. unde<lb/> cimi</s> </p> <p type="margin"> <s id="s.000223"><margin.target id="marg27"/>10. unde­<lb/> cimi</s> </p> <p type="margin"> <s id="s.000224"><margin.target id="marg28"/>4. &longs;exti</s> </p> <p type="margin"> <s id="s.000225"><margin.target id="marg29"/>per 5. pe­<lb/> titionem <lb/> Archime<lb/> dis.</s> </p> <p type="head"> <s id="s.000226">COROLLARIVM.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000227">Ex iam demon&longs;tratis per&longs;picue apparet, cuius <lb/> libet pri&longs;matis axem, parallelogrammorum lateri<lb/> bus, quæ ab oppo&longs;itis planis <expan abbr="ducũtur">ducuntur</expan> æquidi&longs;tare.</s> </p> <p type="head"> <s id="s.000228">THEOREMA VI. PROPOSITIO VI.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000229">Cuiuslibet pri&longs;matis centrum grauitatis e&longs;t in <lb/> plano, quod oppo&longs;itis planis æquidi&longs;tans, reli­<lb/> quorum planorum latera bifariam diuidit.</s> </p> <p type="main"> <s id="s.000230">Sit pri&longs;ma, in quo plana, quæ opponuntur &longs;int trian­<lb/> gula ace, bdf: & parallelogrammorum latera ab, cd, <lb/> ef bifariam <expan abbr="diuidãtur">diuidantur</expan> in punctis ghk: per diui&longs;iones au­<lb/> <arrow.to.target n="marg30"/><lb/> tem planum ducatur; cuius &longs;ectio figura ghK. <!-- KEEP S--></s> <s id="s.000231">erit linea <lb/> gh æquidi&longs;tans lineis ac, bd & hk ip&longs;is ce, df. </s> <s id="s.000232">quare ex <lb/> decimaquinta undecimi elementorum, planum illud pla<lb/> nis ace, bdf æquidi&longs;tabit, & faciet &longs;ectionem figu­<lb/> <arrow.to.target n="marg31"/><lb/> ram ip&longs;is æqualem, & &longs;imilem, ut proxime demon&longs;tra­<lb/> uimus. </s> <s id="s.000233">Dico centrum grauitatis pri&longs;matis e&longs;&longs;e in plano <lb/> ghk. </s> <s id="s.000234">Si enim fieri pote&longs;t, &longs;it eius centrum l: & ducatur <lb/> lm u&longs;que ad planum ghk, quæ ip&longs;i ab æquidi&longs;tet. </s> <pb xlink:href="023/01/024.jpg"/> <s id="s.000235"><arrow.to.target n="marg32"/>ergo linea ag continenter in duas partes æquales diui­<lb/> &longs;a, relinquetur <expan abbr="tãdem">tandem</expan> pars aliqua ng, quæ minor erit lm. </s> <lb/> <s id="s.000236">Vtraque uero linearum ag, gb diuidatur in partes æqua­<lb/> les ip&longs;i ng: & per puncta diui&longs;ionum plana oppo&longs;itis pla­<lb/> <arrow.to.target n="marg33"/><lb/> nis æquidi&longs;tantia ducantur. </s> <s id="s.000237">erunt &longs;ectiones figuræ æqua­<lb/> les, ac &longs;imiles ip&longs;is ace, bdf: & totum pri&longs;ma diui&longs;um erit <lb/> in pri&longs;mata æqualia, & &longs;imilia: quæ cum inter &longs;e <expan abbr="congruãt">congruant</expan>; <lb/> & grauitatis centra &longs;ibi ip&longs;is congruentia, <expan abbr="re&longs;pondentiaq;">re&longs;pondentiaque</expan> <lb/> <figure id="id.023.01.024.1.jpg" xlink:href="023/01/024/1.jpg"/><lb/> habebunt. </s> <s id="s.000238"><expan abbr="Itaq:">Itaque</expan> <lb/> &longs;unt magnitudi­<lb/> nes <expan abbr="quædã">quædam</expan> æqua­<lb/> les ip&longs;i nh, & nu­<lb/> mero pares, qua­<lb/> rum centra gra­<lb/> uitatis in <expan abbr="ead&etilde;re">eadem</expan> re<lb/> cta linea con&longs;ti­<lb/> tuuntur: duæ ue­<lb/> ro mediæ æqua­<lb/> les &longs;unt: & quæ ex <lb/> utraque parte i­<lb/> p&longs;arum &longs;imili­<lb/> ter æquales: & æ­<lb/> quales rectæ li­<lb/> neæ, quæ inter <lb/> grauitatis centra <lb/> interiiciuntur. </s> <lb/> <s id="s.000239">quare ex corolla­<lb/> rio quintæ pro­<lb/> po&longs;itionis primi <lb/> libri Archimedis <lb/> de centro graui­<lb/> tatis planorum; magnitudinis ex his omnibus compo&longs;itæ <lb/> centrum grauitatis e&longs;t in medio lineæ, quæ magnitudi­<lb/> num mediarum centra coniungit. </s> <s id="s.000240">at qui non ita res ha­ <pb pagenum="9" xlink:href="023/01/025.jpg"/>bet, &longs;i quidem l extra medias magnitudines po&longs;itum e&longs;t. </s> <lb/> <s id="s.000241">Con&longs;tat igitur centrum grauitatis pri&longs;matis e&longs;&longs;e in plano <lb/> <figure id="id.023.01.025.1.jpg" xlink:href="023/01/025/1.jpg"/><lb/> ghk, quod nos demon&longs;trandum propo&longs;uimus. </s> <s id="s.000242">At &longs;i op­<lb/> po&longs;ita plana in pri&longs;mate &longs;int quadrilatera, uel plurilatera, <lb/> eadem erit in omnibus demon&longs;tratio.</s> </p> <p type="margin"> <s id="s.000243"><margin.target id="marg30"/>33. primi</s> </p> <p type="margin"> <s id="s.000244"><margin.target id="marg31"/>5. huius</s> </p> <p type="margin"> <s id="s.000245"><margin.target id="marg32"/>1. decimi</s> </p> <p type="margin"> <s id="s.000246"><margin.target id="marg33"/>5 huius</s> </p> <p type="head"> <s id="s.000247">THEOREMA VII. PROPOSITIO VII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000248">Cuiuslibet cylindri, & cuiuslibet cylindri por<lb/> tionis centrum grauitatis e&longs;t in plano, quod ba&longs;i­<lb/> bus æquidi&longs;tans, parallelogrammi per axem late­<lb/> ra bifariam &longs;ecat.</s> </p> <pb xlink:href="023/01/026.jpg"/> <p type="main"> <s id="s.000249">SIT cylindrus, uel cylindri portio ac: & plano per a­<lb/> xem ducto &longs;ecetur; cuius &longs;ectio &longs;it parallelogrammum ab<lb/> cd: & bifariam diui&longs;is ad, bc parallelogrammi lateribus, <lb/> per diui&longs;ionum puncta ef planum ba&longs;i æquidi&longs;tans duca­<lb/> tur; quod faciet &longs;ectionem, in cylindro quidem circulum <lb/> æqualem iis, qui &longs;unt in ba&longs;ibus, ut demon&longs;trauit Serenus <lb/> in libro cylindricorum, propo&longs;itione quinta: in cylindri <lb/> uero portione ellip&longs;im æqualem, & &longs;imilem eis, quæ &longs;unt <lb/> <figure id="id.023.01.026.1.jpg" xlink:href="023/01/026/1.jpg"/><lb/> in oppo&longs;itis planis, quod nos <lb/>demon&longs;trauimus in commen<lb/> tariis in librum Archimedis <lb/> de conoidibus, & &longs;phæroidi­<lb/> bus. </s> <s id="s.000250">Dico centrum grauita­<lb/> tis cylindri, uel cylindri por­<lb/> tionis e&longs;&longs;e in plano ef. </s> <s id="s.000251">Si <expan abbr="enĩ">enim</expan> <lb/> fieri pote&longs;t, fit centrum g: & <lb/> ducatur gh ip&longs;i ad æquidi­<lb/> &longs;tans, u&longs;que ad ef planum. </s> <lb/> <s id="s.000252">Itaque linea ae continenter <lb/> diui&longs;a bifariam, erit tandem <lb/> pars aliqua ip&longs;ius ke, minor <lb/> gh. </s> <s id="s.000253">Diuidantur ergo lineæ <lb/> ae, ed in partes æquales ip&longs;i <lb/> ke: & per diui&longs;iones plana ba<lb/> &longs;ibus æquidi&longs;tantia <expan abbr="ducãtur">ducantur</expan>. </s> <lb/> <s id="s.000254">erunt iam &longs;ectiones, figuræ æ­<lb/> quales, & &longs;imiles eis, quæ &longs;unt <lb/> in ba&longs;ibus: atque erit cylindrus in cylindros diui&longs;us: & cy<lb/> lindri portio in portiones æquales, & &longs;imiles ip&longs;i kf. </s> <s id="s.000255">reli­<lb/> qua &longs;imiliter, ut &longs;uperius in pri&longs;mate concludentur.</s> </p> <pb pagenum="10" xlink:href="023/01/027.jpg"/> <figure id="id.023.01.027.1.jpg" xlink:href="023/01/027/1.jpg"/> <p type="head"> <s id="s.000256">THEOREMA VIII. PROPOSITIO VIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000257">Cuiuslibet pri&longs;matis, & cuiuslibet cylindri, uel <lb/> cylindri portionis grauitatis centrum in medio <lb/> ip&longs;ius axis con&longs;i&longs;tit.</s> </p> <p type="main"> <s id="s.000258">Sit primum af pri&longs;ma æquidi&longs;tantibus planis <expan abbr="contentũ">contentum</expan>, <lb/> quod &longs;olidum parallelepipedum appellatur: & oppo&longs;ito­<lb/> rum planorum cf, ah, da, fg latera bifariam diuidantur in <lb/> punctis klmnopqrstux: & per diui&longs;iones ducantur <lb/> plana kn, or, sx. </s> <s id="s.000259">communes autem eorum planorum &longs;e­<lb/> ctiones &longs;int lineæ yz, <foreign lang="greek">qf, xy:</foreign> quæ in puncto <foreign lang="greek">w</foreign> <expan abbr="conueniãt">conueniant</expan>. </s> <lb/> <s id="s.000260">erit ex decima eiu&longs;dem libri Archimedis parallelogrammi <lb/> cf centrum grauitatis punctum y; parallelogrammi ah <pb xlink:href="023/01/028.jpg"/>centrum z: parallelogrammi ad, <foreign lang="greek">q:</foreign> parallelogrammi fg, <foreign lang="greek">f:</foreign><lb/> <figure id="id.023.01.028.1.jpg" xlink:href="023/01/028/1.jpg"/><lb/> parallelogrammi dh, <foreign lang="greek">x:</foreign> & <lb/> parallelogrammi cg <expan abbr="centrũ">centrum</expan> <lb/> <foreign lang="greek">y:</foreign> atque erit <foreign lang="greek">w</foreign> punctum me <lb/> dium uniu&longs;cuiu&longs;que axis, ui <lb/> delicet eius lineæ quæ oppo <lb/> &longs;itorum <expan abbr="planorũ">planorum</expan> centra con <lb/> iungit. </s> <s id="s.000261">Dico <foreign lang="greek">w</foreign> centrum e&longs;&longs;e <lb/> grauitatis ip&longs;ius &longs;olidi. </s> <s id="s.000262">e&longs;t <lb/> <arrow.to.target n="marg34"/><lb/> enim, ut demon&longs;trauimus, <lb/> &longs;olidi af centrum grauitatis <lb/> in plano Kn; quod oppo&longs;i­<lb/> tis planis ad, gf æquidi&longs;tans <lb/> reliquorum planorum late­<lb/> ra bifariam diuidit: & &longs;imili <lb/> ratione idem centrum e&longs;t in plano or, æquidi&longs;tante planis <lb/> ae, bf oppo&longs;itis. </s> <s id="s.000263">ergo in communi ip&longs;orum &longs;ectione: ui­<lb/> delicet in linea yz. </s> <s id="s.000264">Sed e&longs;t etiam in plano tu, quod <expan abbr="quid&etilde;">quidem</expan> <lb/> yz &longs;ecatin <foreign lang="greek">w.</foreign> Con&longs;tat igitur centrum grauitatis &longs;olidi e&longs;&longs;e <lb/> punctum <foreign lang="greek">w,</foreign> medium &longs;cilicet axium, hoc e&longs;t linearum, quæ <lb/> planorum oppo&longs;itorum centra coniungunt.</s> </p> <p type="margin"> <s id="s.000265"><margin.target id="marg34"/>6 huius</s> </p> <p type="main"> <s id="s.000266">Sit aliud prima af; & in eo plana, quæ opponuntur, tri­<lb/> angula abc, def: <expan abbr="diui&longs;isq;">diui&longs;isque</expan> bifariam parallelogrammorum <lb/> lateribus ad, be, cf in punctis ghk, per diui&longs;iones <expan abbr="planũ">planum</expan> <lb/> ducatur, quod oppo&longs;itis planis æquidi&longs;tans faciet <expan abbr="&longs;ection&etilde;">&longs;ectionem</expan> <lb/> triangulum ghx æquale, & &longs;imile ip&longs;is abc, def. </s> <s id="s.000267">Rur&longs;us <lb/> diuidatur ab bifariam in l: & iuncta cl per ip&longs;am, & per <lb/> cKf planum ducatur pri&longs;ma &longs;ecans, cuius, & <expan abbr="parallelogrã">parallelogram</expan><lb/> mi ae communis &longs;ectio &longs;it lmn. </s> <s id="s.000268">diuidet punctum m li­<lb/> neam gh bifariam; & ita n diuidet lineam de: quoniam <lb/> <arrow.to.target n="marg35"/><lb/> triangula acl, gkm, dfn æqualia &longs;unt, & &longs;imilia, ut &longs;upra <lb/> demon&longs;trauimus. </s> <s id="s.000269">Iam ex iis, quæ tradita &longs;unt, con&longs;tat cen<lb/> trum grauitatis pri&longs;matis in plano ghk contineri. </s> <s id="s.000270">Dico <lb/> ip&longs;um e&longs;&longs;e in linea km. </s> <s id="s.000271">Si enim fieri pote&longs;t, &longs;it o centrum; <pb pagenum="11" xlink:href="023/01/029.jpg"/>& per o ducatur op ad km ip&longs;i hg æquidi&longs;tans. </s> <s id="s.000272">Itaque li<lb/> nea hm <expan abbr="bifariã">bifariam</expan> u&longs;que eò diuidatur, quoad reliqua &longs;it pars <lb/> quædam qm, minor op. </s> <s id="s.000273">deinde hm, mg diuidantur in <lb/> partes æquales ip&longs;i mq: & per diui&longs;iones lineæ ip&longs;i mK <lb/> æquidi&longs;tantes ducantur. </s> <s id="s.000274">puncta uero, in quibus hæ trian­<lb/> gulorum latera &longs;ecant, coniungantur ductis lineis rs, tu, <lb/> <figure id="id.023.01.029.1.jpg" xlink:href="023/01/029/1.jpg"/><lb/> xy; quæ ba&longs;i gh æquidi&longs;tabunt. </s> <s id="s.000275">Quoniam enim lineæ gz, <lb/> h<foreign lang="greek">a</foreign> &longs;unt æquales: <expan abbr="itemq;">itemque</expan> æquales gm, mh: ut mg ad gz, <lb/> ita erit mh, ad h<foreign lang="greek">a:</foreign> & diuidendo, ut mz ad zg, ita m<foreign lang="greek">a</foreign> ad <lb/> <arrow.to.target n="marg36"/><lb/> <foreign lang="greek">a</foreign>h. </s> <s id="s.000276">Sed ut mz ad zg, ita kr ad rg: & ut m<foreign lang="greek">a</foreign> ad <foreign lang="greek">a</foreign>h, ita ks <lb/> ad sh. </s> <s id="s.000277">quare ut kr ad rg, ita ks ad sh. </s> <s id="s.000278">æquidi&longs;tant igitur <lb/> <arrow.to.target n="marg37"/><lb/> inter &longs;e &longs;e rs, gh. </s> <s id="s.000279">eadem quoque ratione demon&longs;trabimus <pb xlink:href="023/01/030.jpg"/>tu, xy ip&longs;i gh æquidi&longs;tare. </s> <s id="s.000280">Et quoniam triangula, quæ <lb/> fiunt à lineis Ky, yu, us, sh æqualia &longs;unt inter &longs;e, & &longs;imilia <lb/> <arrow.to.target n="marg38"/><lb/> triangulo Kmh: habebit triangulum Kmh ad <expan abbr="triangulũ">triangulum</expan> <lb/> K<foreign lang="greek">d</foreign>y duplam proportionem eius, quæ e&longs;t lineæ kh ad Ky. </s> <lb/> <s id="s.000281">&longs;ed Kh po&longs;ita e&longs;t quadrupla ip&longs;ius ky. </s> <s id="s.000282">ergo triangulum <lb/> kmh ad triangulum K<foreign lang="greek">d</foreign>y <expan abbr="eãdem">eandem</expan> proportionem habebit, <lb/> quam &longs;exdecim ad <expan abbr="unũ">unum</expan>: & ad quatuor triangula k<foreign lang="greek">d</foreign>y, yu, <lb/> us, s<foreign lang="greek">a</foreign>h habebit eandem, quam &longs;exdecim ad quatuor, hoc <lb/>e&longs;t quam hK ad ky: & &longs;imiliter eandem habere demon&longs;tra<lb/> <figure id="id.023.01.030.1.jpg" xlink:href="023/01/030/1.jpg"/><lb/> bitur trian­<lb/> gulum kmg <lb/> ad quatuor <lb/> <expan abbr="triãgula">triangula</expan> K<foreign lang="greek">d</foreign><lb/> x, x<foreign lang="greek">g</foreign>t, t<foreign lang="greek">b</foreign>r, <lb/> <arrow.to.target n="marg39"/><lb/> rzg. <!-- KEEP S--></s> <s id="s.000283">quare <lb/>totum trian<lb/> gulum Kgh <lb/> ad omnia tri <lb/> angula gzr, <lb/> r<foreign lang="greek">b</foreign>t, t<foreign lang="greek">g</foreign>x, x<foreign lang="greek">d</foreign><lb/> K, K<foreign lang="greek">d</foreign>y, yu, <lb/> us, s<foreign lang="greek">a</foreign>h ita <lb/> erit, ut hk ad <lb/> ky, hoc e&longs;t <lb/> ut hm ad m<lb/> q. </s> <s id="s.000284">Si igitur in <lb/> triangulis abc, def de&longs;cribantur figuræ &longs;imiles ei, quæ de­<lb/> &longs;cripta e&longs;t in ghK triangulo: & per lineas &longs;ibi re&longs;ponden­<lb/> tes plana ducantur: totum pri&longs;ma af diui&longs;um erit in tria <lb/> &longs;olida parallelepipeda y<foreign lang="greek">g,</foreign> u<foreign lang="greek">b,</foreign> sz, quorum ba&longs;es &longs;unt æqua <lb/> les & &longs;imiles ip&longs;is parallelogrammis y <foreign lang="greek">g,</foreign>u<foreign lang="greek">b,</foreign> sz: & in octo <lb/> pri&longs;mata gzr, r<foreign lang="greek">b</foreign>t, t<foreign lang="greek">g</foreign>x, x<foreign lang="greek">d</foreign><lb/> K, k<foreign lang="greek">d</foreign>y, yu, us, s<foreign lang="greek">a</foreign>h: quorum <lb/> item ba&longs;es æquales, & &longs;imiles &longs;unt dictis triangulis; altitu­<lb/> do autem in omnibus, totius pri&longs;matis altitudini æqualis. <pb pagenum="12" xlink:href="023/01/031.jpg"/>Itaque &longs;olidi parallelepipedi y<foreign lang="greek">g</foreign> centrum grauitatis e&longs;t in <lb/> linea <foreign lang="greek">de:</foreign> &longs;olidi u<foreign lang="greek">b</foreign> centrum e&longs;t in linea <foreign lang="greek">eh:</foreign> & &longs;olidi sz in li<lb/> nea <foreign lang="greek">h</foreign>m, quæ quidem lineæ axes &longs;unt, cum planorum oppo<lb/> &longs;itorum centra coniungant. </s> <s id="s.000285">ergo magnitudinis ex his &longs;oli <lb/> dis compo&longs;itæ centrum grauitatis e&longs;t in linea <foreign lang="greek">d</foreign>m, quod &longs;it <lb/> <foreign lang="greek">q</foreign>; & iuncta <foreign lang="greek">q</foreign>o producatur: à puncto autem h ducatur h<foreign lang="greek">a</foreign><lb/> ip&longs;i mk æquidi&longs;tans, quæ cum <foreign lang="greek">q</foreign>o in <foreign lang="greek">m</foreign> conueniat. </s> <s id="s.000286">triangu<lb/> lum igitur ghk ad omnia triangula gzr, <foreign lang="greek">b</foreign>t, t<foreign lang="greek">g</foreign>x, x<foreign lang="greek">d</foreign>k, <lb/> k<foreign lang="greek">d</foreign>y, yu, us, s<foreign lang="greek">a</foreign>h eandem habet proportionem, quam hm <lb/> ad mq ; hoc e&longs;t, quam <foreign lang="greek">mq</foreign> ad <foreign lang="greek">ql:</foreign> nam &longs;i hm, <foreign lang="greek">mq</foreign> produci in<lb/> telligantur, quou&longs;que coeant; erit ob linearum qy, mk æ­<lb/> quidi&longs;tantiam, ut hq ad qm, ita <foreign lang="greek">ml</foreign> ad ad <foreign lang="greek">lq:</foreign> & componen <lb/> do, ut hm ad mq, ita <foreign lang="greek">mq</foreign> ad <foreign lang="greek">ql.</foreign></s> <s id="s.000287"> linea uero <foreign lang="greek">q</foreign>o maior e&longs;t, <lb/> <arrow.to.target n="marg40"/><lb/> quàm <foreign lang="greek">ql:</foreign> habebit igitur <foreign lang="greek">mq</foreign> ad <foreign lang="greek">ql</foreign> maiorem proportio­<lb/> nem, quàm ad <foreign lang="greek">q</foreign>o. </s> <s id="s.000288">quare triangulum etiam ghk ad omnia <lb/> iam dicta triangula maiorem <expan abbr="proportion&etilde;">proportionem</expan> habebit, quàm <lb/> <foreign lang="greek">mq</foreign> ad <foreign lang="greek">q</foreign>o. </s> <s id="s.000289">&longs;ed ut <expan abbr="triangulũ">triangulum</expan> ghk ad omnia triangula, ita <expan abbr="to-tũ">to­<lb/> tum</expan> pri&longs;ma afad omnia pri&longs;mata gzr, r<foreign lang="greek">b</foreign>t, t<foreign lang="greek">g</foreign>x, x<foreign lang="greek">dk, kd</foreign> y, <lb/> yu, us, s<foreign lang="greek">a</foreign>h: quoniam enim &longs;olida parallelepipeda æque al<lb/> ta, eandem inter &longs;e proportionem habent, quam ba&longs;es; ut <lb/> ex trige&longs;ima&longs;ecunda undecimi elementorum con&longs;tat. </s> <s id="s.000290">&longs;unt <lb/> <arrow.to.target n="marg41"/><lb/> autem &longs;olida parallelepipeda pri&longs;matum triangulares ba­<lb/> <arrow.to.target n="marg42"/><lb/> &longs;es habentium dupla: &longs;equitur, ut etiam huiu&longs;modi pri&longs;­<lb/> mata inter &longs;e &longs;int, &longs;icut eorum ba&longs;es. </s> <s id="s.000291">ergo totum pri&longs;ma ad <lb/> omnia pri&longs;mata maiorem proportionem habet, quam <foreign lang="greek">mq</foreign><lb/> <arrow.to.target n="marg43"/><lb/> ad <foreign lang="greek">q</foreign>o: & diuidendo &longs;olida parallelepipeda y<foreign lang="greek">g,</foreign> u<foreign lang="greek">b,</foreign> sz ad o­<lb/> mnia pri&longs;mata proportionem habent maiorem, quàm <foreign lang="greek">m</foreign>o <lb/> ad o<foreign lang="greek">q</foreign>. </s> <s id="s.000292">fiat <foreign lang="greek">n</foreign>o ad o<foreign lang="greek">q,</foreign> ut &longs;olida parallelepipeda y <foreign lang="greek">g,</foreign> u<foreign lang="greek">b,</foreign> sz ad <lb/> omnia pri&longs;mata. </s> <s id="s.000293">Itaque cum à pri&longs;mate af, cuius <expan abbr="c&etilde;trum">centrum</expan> <lb/> grauitatis e&longs;t o, auferatur magnitudo ex &longs;olidis parallelepi<lb/> pedis y <foreign lang="greek">g,</foreign>u<foreign lang="greek">b,</foreign>sz con&longs;tans: atque ip&longs;ius grauitatis centrum <lb/> &longs;it <foreign lang="greek">q:</foreign> reliquæ magnitudinis, quæ ex omnibus pri&longs;matibus <lb/> con&longs;tat, grauitatis centrum erit in linea <foreign lang="greek">q</foreign> o producta: & <lb/> in puncto <foreign lang="greek">v</foreign>, ex octava propo&longs;itione eiusdem libri Archi­ <pb xlink:href="023/01/032.jpg"/>medis. </s> <s id="s.000294">ergo punctum <foreign lang="greek">n</foreign> extra pri&longs;ma af po&longs;itum, <expan abbr="centrũ">centrum</expan> <lb/> erit magnitudinis <expan abbr="cõpo&longs;itæ">compo&longs;itæ</expan> ex omnibus pri&longs;matibus gzr, <lb/> r <foreign lang="greek">b</foreign>t, t<foreign lang="greek">g</foreign>x, x<foreign lang="greek">d</foreign>k, k<foreign lang="greek">d</foreign> y, yu, us, s<foreign lang="greek">a</foreign>h, quod fieri nullo modo po<lb/> te&longs;t. </s> <s id="s.000295">e&longs;t enim ex diffinitione centrum grauitatis &longs;olidæ figu<lb/> ræ intra ip&longs;am po&longs;itum, non extra. </s> <s id="s.000296">quare relinquitur, ut <expan abbr="c&etilde;trum">cen<lb/> trum</expan> grauitatis pri&longs;matis &longs;it in linea Km. </s> <s id="s.000297">Rur&longs;us bc bifa­<lb/> riam in diuidatur: & ducta a<foreign lang="greek">x,</foreign> per ip&longs;am, & per lineam <lb/>agd planum ducatur; quod pri&longs;ma &longs;ecet: <expan abbr="faciatq;">faciatque</expan> in paral<lb/> lelogrammo bf &longs;ectionem <foreign lang="greek">x p</foreign> diuidet punctum <foreign lang="greek">p</foreign> lineam <lb/> quoque cf bifariam: & erit plani eius, & trianguli ghK <lb/> communis &longs;ectio gu; quòd <expan abbr="pũctum">punctum</expan> u in medio lineæ hK <lb/> <figure id="id.023.01.032.1.jpg" xlink:href="023/01/032/1.jpg"/><lb/> po&longs;itum &longs;it. </s> <s id="s.000298">Similiter demon&longs;trabimus centrum grauita­<lb/> tis pri&longs;matis in ip&longs;a gu ine&longs;&longs;e. </s> <s id="s.000299">&longs;it autem planorum cfnl, <lb/> ad<foreign lang="greek">px</foreign> communis &longs;ectio linea <foreign lang="greek">rst;</foreign> quæ quidem pri&longs;matis <lb/> axis erit, cum tran&longs;eat per centra grauitatis triangulorum <lb/> abc, ghk def, ex quartadecima eiu&longs;dem. </s> <s id="s.000300">ergo centrum <lb/> grauitatis pri&longs;matis af e&longs;t punctum <foreign lang="greek">s,</foreign> centrum &longs;cilicet <pb pagenum="13" xlink:href="023/01/033.jpg"/>trianguli ghK, & ip&longs;ius <foreign lang="greek">rt</foreign> axis medium.</s> </p> <p type="margin"> <s id="s.000301"><margin.target id="marg35"/>5.huius</s> </p> <p type="margin"> <s id="s.000302"><margin.target id="marg36"/>2. &longs;exti.<lb/> 12 quinti.</s> </p> <p type="margin"> <s id="s.000303"><margin.target id="marg37"/>2. &longs;exti.</s> </p> <p type="margin"> <s id="s.000304"><margin.target id="marg38"/> 19. &longs;exti</s> </p> <p type="margin"> <s id="s.000305"><margin.target id="marg39"/>2. uel 12. <lb/> quinti.</s> </p> <p type="margin"> <s id="s.000306"><margin.target id="marg40"/>8. quinti.<!-- KEEP S--></s> </p> <p type="margin"> <s id="s.000307"><margin.target id="marg41"/>28. unde<lb/> cimi</s> </p> <p type="margin"> <s id="s.000308"><margin.target id="marg42"/>15. quinti</s> </p> <p type="margin"> <s id="s.000309"><margin.target id="marg43"/>19. quinti<lb/> apud <expan abbr="Cãpanum">Cam<lb/> panum</expan></s> </p> <p type="main"> <s id="s.000310">Sit pri&longs;ma ag, cuius oppo&longs;ita plana &longs;int quadrilatera <lb/> abcd, efgh: <expan abbr="&longs;ecenturq;">&longs;ecenturque</expan> ac, bf, cg, dh bifariam: & per di­<lb/> ui&longs;iones planum ducatur; quod &longs;ectionem faciat quadrila­<lb/> terum Klmn. </s> <s id="s.000311">Deinde iuncta ac per lineas ac, ae ducatur <lb/> planum <expan abbr="&longs;ecãs">&longs;ecans</expan> pri&longs;ma, quod ip&longs;um diuidet in duo pri&longs;mata <lb/> triangulares ba&longs;es habentia abcefg, adcehg. </s> <s id="s.000312">Sint <expan abbr="aut&etilde;">autem</expan> <lb/> <figure id="id.023.01.033.1.jpg" xlink:href="023/01/033/1.jpg"/><lb/> triangulorum abc, efg gra­<lb/> uitatis centra op: & triangu­<lb/> lorum adc, ehg centra qr: <lb/> <expan abbr="iunganturq;">iunganturque</expan> op, qr; quæ pla­<lb/> no klmn occurrant in pun­<lb/> ctis st. </s> <s id="s.000313">erit ex iis, quæ demon<lb/> &longs;trauimus, punctum s grauita<lb/> tis centrum trianguli klm; & <lb/> ip&longs;ius pri&longs;matis abcefg: pun<lb/> ctum uero t centrum grauita <lb/> tis trianguli Knm, & pri&longs;ma­<lb/> tis adc, ehg. <!-- KEEP S--></s> <s id="s.000314">iunctis igitur <lb/> oq, pr, st, erit in linea oq <expan abbr="c&etilde;">cen</expan> <lb/> trum grauitatis quadrilateri <lb/> abcd, quod &longs;it u: & in linea <lb/> pr <expan abbr="c&etilde;trum">centrum</expan> quadrilateri efgh <lb/> &longs;it autem x. </s> <s id="s.000315">denique iungatur <lb/> u x, quæ &longs;ecet lineam &longs; t in y. </s> <s id="s.000316">&longs;e<lb/> cabit enim cum &longs;int in eodem <lb/> <arrow.to.target n="marg44"/><lb/> plano: <expan abbr="atq;">atque</expan> erit y grauitatis centrum quadrilateri Klmn. </s> <lb/> <s id="s.000317">Dico idem punctum y centrum quoque gra uitatis e&longs;&longs;e to­<lb/> tius pri&longs;matis. </s> <s id="s.000318">Quoniam enim quadrilateri klmn graui­<lb/> tatis centrum e&longs;t y: linea sy ad yt ean dem proportionem <lb/> habebit, quam triangulum knm ad triangulum klm, ex 8 <lb/> Archimedis de centro grauitatis planorum. </s> <s id="s.000319">Vt autem <expan abbr="triã">trian</expan><lb/> gulum knm ad ip&longs;um klm, hoc e&longs;t ut triangulum adc ad <lb/> triangulum abc, æqualia enim &longs;unt, ita pri&longs;ma adcehg <pb xlink:href="023/01/034.jpg"/>ad pri&longs;ma abcefg. <!-- KEEP S--></s> <s id="s.000320">quare linea sy ad yt eandem propor­<lb/> tionem habet, quam pri&longs;ma adcehg ad pri&longs;ma abcefg. <!-- KEEP S--></s> <lb/> <s id="s.000321">Sed pri&longs;matis abcefg centrum grauitatis e&longs;t s: & pri&longs;ma­<lb/> tis adcehg centrum t. </s> <s id="s.000322">magnitudinis igitur ex his compo<lb/> &longs;itæ hoc e&longs;t totius pri&longs;matis ag centrum grauitatis e&longs;t pun<lb/> ctum y; medium &longs;cilicet axis ux, qui oppo&longs;itorum plano­<lb/> rum centra coniungit.</s> </p> <p type="margin"> <s id="s.000323"><margin.target id="marg44"/>5. huius/></s> </p> <p type="main"> <s id="s.000324">Rur&longs;us &longs;it pri&longs;ma ba&longs;im habens pentagonum abcde: <lb/> & quod ei opponitur &longs;it fghKl: &longs;ec<expan abbr="enturq;">enturque</expan> af, bg, ch, <lb/> dk, el bifariam: & per diui&longs;iones ducto plano, &longs;ectio &longs;it <expan abbr="p&etilde;">pen</expan><lb/> <expan abbr="tagonũ">tagonum</expan> mnopq. deinde iuncta eb per lineas le, eb aliud <lb/> <figure id="id.023.01.034.1.jpg" xlink:href="023/01/034/1.jpg"/><lb/> planum ducatur, <expan abbr="diuid&etilde;s">diuidens</expan> pri&longs;<lb/> ma ak in duo pri&longs;mata; in pri&longs;<lb/> ma &longs;cilicet al, cuius plana op­<lb/> po&longs;ita &longs;int triangula abe fgl: <lb/> & in prima bk cuius plana op<lb/> po&longs;ita &longs;int quadrilatera bcde <lb/> ghkl. <!-- KEEP S--></s> <s id="s.000325">Sint autem triangulo­<lb/>rum abe, fgl centra grauita<lb/> tis puncta r &longs;: & bcde, ghkl <lb/> quadrilaterorum centra tu: <lb/> <expan abbr="iunganturq;">iunganturque</expan> rs, tu occurren­<lb/> tes plano mnopq in punctis <lb/> xy. </s> <s id="s.000326">& itidem <expan abbr="iungãtur">iungantur</expan> rt, &longs;u, <lb/> xy. </s> <s id="s.000327">erit in linea rt <expan abbr="c&etilde;trum">centrum</expan> gra<lb/> uitatis pentagoni abcde; <lb/> quod &longs;it z: & in linea &longs;u cen­<lb/> trum pentagoni fghkl :&longs;it au <lb/> tem <foreign lang="greek">x:</foreign> & ducatur z<foreign lang="greek">x,</foreign> quæ di­<lb/> cto plano in <foreign lang="greek">y</foreign> occurrat. </s> <s id="s.000328"><expan abbr="Itaq;">Itaque</expan> <lb/> punctum x e&longs;t centrum graui <lb/> tatis trianguli mnq, ac pri&longs;­<lb/> matis al: & y grauitatis centrum quadrilateri nopq, ac <lb/> pri&longs;matis bk. </s> <s id="s.000329">quare y centrum erit pentagoni mnopq. </s> <s id="s.000330"> & <pb pagenum="14" xlink:href="023/01/035.jpg"/>&longs;imiliter demon&longs;trabitur totius pri&longs;matis aK grauitatis ef <lb/> &longs;e centrum. </s> <s id="s.000331">Simili ratione & in aliis pri&longs;matibus illud <lb/> idem facile demon&longs;trabitur. </s> <s id="s.000332">Quo autem pacto in omni <lb/> figura rectilinea centrum grauitatis inueniatur, docuimus <lb/> in commentariis in &longs;extam propo&longs;itionem Archimedis de <lb/> quadratura parabolæ.</s> </p> <p type="main"> <s id="s.000333">Sit cylindrus, uel cylindri portio ce cuius axis ab: &longs;ece­<lb/> <expan abbr="turq,">turque</expan> plano per axem ducto; quod &longs;ectionem faciat paral­<lb/> lelogrammum cdef: & diui&longs;is cf, de bifariam in punctis <lb/> <figure id="id.023.01.035.1.jpg" xlink:href="023/01/035/1.jpg"/><lb/> gh, per ea ducatur planum ba&longs;i æquidi&longs;tans. </s> <s id="s.000334">erit &longs;ectio gh <lb/> circulus, uel ellip&longs;is, centrum habens in axe; quod &longs;it K at­<lb/> <arrow.to.target n="marg45"/><lb/> que erunt ex iis, quæ demon&longs;trauimus, centra grauitatis <lb/> planorum oppo&longs;itorum puncta ab: & plani gh ip&longs;um k in <lb/> quo quidem plano e&longs;t centrum grauitatis cylindri, uel cy­<lb/> lindri portionis. </s> <s id="s.000335">Dico punctum K cylindri quoque, uel cy<lb/> lindri portionis grauitatis centrum e&longs;&longs;e. </s> <s id="s.000336">Si enim fieri po­<lb/> te&longs;t, &longs;it l centrum: <expan abbr="ducaturq;">ducaturque</expan> kl, & extra figuram in m pro­<lb/> ducatur. </s> <s id="s.000337">quam ucro proportionem habet linea mK ad kl <pb xlink:href="023/01/036.jpg"/>habeat circulus, uel ellip&longs;is gh ad aliud &longs;pacium, in quo u: <lb/> & in cit culo, uel ellip&longs;i plane de&longs;cribatur rectilinea figura, <lb/> ita ut <expan abbr="tãdem">tandem</expan> <expan abbr="relinquãtur">relinquantur</expan> portiones minores &longs;pacio u, quæ <lb/> &longs;it opgqrsht: <expan abbr="de&longs;criptaq;">de&longs;criptaque</expan> &longs;imili figura in oppo&longs;itis pla­<lb/> nis cd, fe, per lineas &longs;ibi ip&longs;is re&longs;pondentes plana <expan abbr="ducãtur">ducantur</expan>. </s> <lb/> <s id="s.000338">Itaque cylindrus, uel cylindri portio diuiditur in pri&longs;ma, <lb/> cuius quidem ba&longs;is e&longs;t figura rectilinea iam dicta, centrum <lb/>que grauitatis punctum K: & in multa &longs;olida, quæ pro ba&longs;i<lb/> bus habent relictas portiones, quas nos &longs;olidas portiones <lb/> appellabimus. </s> <s id="s.000339">cum igitur portiones &longs;int minores &longs;pacio <lb/> u, circulus, uel ellip&longs;is gh ad portiones maiorem propor­<lb/> tionem habebit, quàm linea mk ad Kl. <!-- KEEP S--></s> <s id="s.000340">fiat nk ad Kl, ut <lb/> circulus uel ellip&longs;is gh ad ip&longs;as portiones. </s> <s id="s.000341">Sed ut circulus <lb/> uel ellip&longs;is gh ad figuram rectilineam in ip&longs;a de&longs;cri­<lb/> ptam, ita e&longs;t cylindrus uel cylindri portio ce ad pri&longs;ma, <lb/> quod rectilineam figuram pro ba&longs;i habet, & altitudinem <lb/> æqualem; id, quod infra demon&longs;trabitur. </s> <s id="s.000342">crgo per conuer<lb/> &longs;ionem rationis, ut circulus, uel ellip&longs;is gh ad portiones re<lb/> lictas, ita cylindrus, uel cylindri portio ce ad &longs;olidas por­<lb/> tiones, quate cylindrus uel cylindri portio ad &longs;olidas por­<lb/> tiones eandem proportionem habet, quam linea nk ad k <lb/> & diuidendo pri&longs;ma, cuius ba&longs;is e&longs;t rectilinea figura ad &longs;o­<lb/> lidas portiones eandem proportionem habet, quam nl ad <lb/> lk & quoniam a cylindro uel cylindri portione, cuius gra­<lb/> uitatis centrum e&longs;t l, aufertur pri&longs;ma ba&longs;im habens rectili­<lb/> neam <expan abbr="figurã">figuram</expan>, cuius <expan abbr="centrũ">centrum</expan> grauitatis e&longs;t K: re&longs;iduæ magnitu<lb/> dinis ex &longs;olidis portionibus <expan abbr="cõpo&longs;itæ">compo&longs;itæ</expan> grauitatis <expan abbr="c&etilde;trũ">centrum</expan> erit <lb/> in linea kl protracta, & in puncto n; quod e&longs;t <expan abbr="ab&longs;urdũ">ab&longs;urdum</expan>. </s> <s id="s.000343">relin<lb/> quitur ergo, ut <expan abbr="c&etilde;trum">centrum</expan> grauitatis cylindri; uel cylindri por<lb/> tionis &longs;it <expan abbr="punctũ">punctum</expan> k. </s> <s id="s.000344">quæ omnia <expan abbr="demon&longs;trãda">demon&longs;tranda</expan> propo&longs;uimus.</s> </p> <p type="margin"> <s id="s.000345"><margin.target id="marg45"/>4. huius</s> </p> <p type="main"> <s id="s.000346">At uero cylindrum, uel cylindri <expan abbr="portion&etilde;">portionem</expan> ce <lb/> ad pri&longs;ma, cuius ba&longs;is e&longs;t rectilinea figura in &longs;pa­<lb/> cio gh de&longs;cripta, & altitudo æqualis; eandem ha­ <pb pagenum="15" xlink:href="023/01/037.jpg"/>bere proportionem, quam &longs;pacium gh ad <expan abbr="dictã">dictam</expan> <lb/> figuram, hoc modo demon&longs;trabimus.</s> </p> <p type="main"> <s id="s.000347">Intelligatur circulus, uel ellip&longs;is x æqualis figuræ rectili­<lb/> neæ in gh &longs;pacio de&longs;criptæ. </s> <s id="s.000348">& ab x con&longs;tituatur conus, uel <lb/> <figure id="id.023.01.037.1.jpg" xlink:href="023/01/037/1.jpg"/><lb/> coni portio, <expan abbr="altitudin&etilde;">altitudinem</expan> habens <expan abbr="eand&etilde;">eandem</expan>, <expan abbr="quã">quam</expan> cylindrus uel cy<lb/> lindri portio ce. </s> <s id="s.000349">Sit deinde rectilinea figura, in qua y <expan abbr="ead&etilde;">eadem</expan>, <lb/> quæ in &longs;pacio gh de&longs;cripta e&longs;t: & ab hac pyramis æquealta <lb/> con&longs;tituatur. </s> <s id="s.000350">Dico <expan abbr="conũ">conum</expan> uel coni portione x pyramidi y <expan abbr="æ-qual&etilde;">æ­<lb/> qualem</expan> e&longs;&longs;e. </s> <s id="s.000351">ni&longs;i enim &longs;it æqualis, uel maior, uel minor erit.</s> </p> <p type="main"> <s id="s.000352">Sit primum maior, et exuperet &longs;olido z. </s> <s id="s.000353">Itaque in circu<lb/> lo, uel ellip&longs;i x de&longs;cribatur figura rectilinea; & in ea pyra­<lb/> mis eandem, quam conus, uel coni portio altitudinem ha­<lb/> bens, ita ut portiones relictæ minores &longs;int &longs;olido a, quem­<lb/> admodum docetur in duodecimo libro elementorum pro<lb/> po&longs;itione undecima. </s> <s id="s.000354">erit pyramis x adhuc pyramide y ma<lb/> ior. </s> <s id="s.000355">& quoniam piramides æque altæ inter &longs;e &longs;unt, &longs;icuti ba<lb/> <arrow.to.target n="marg46"/><lb/> &longs;es; pyramis x ad piramidem y eandem proportionem ha­<lb/> bet, quàm figura rectilinea x ad figuram y. </s> <s id="s.000356">Sed figura recti <pb xlink:href="023/01/038.jpg"/><figure id="id.023.01.038.1.jpg" xlink:href="023/01/038/1.jpg"/><lb/> linea x cum &longs;it minor circulo, uel ellip&longs;i, e&longs;t etiam minor fi­<lb/> gura rectilinea y. </s> <s id="s.000357">ergo pyramis x pyramide y minor erit. </s> <lb/> <s id="s.000358">Sed & maior; quod fieri <expan abbr="nõ">non</expan> pote&longs;t. </s> <s id="s.000359">At &longs;i conus, uel coni por<lb/> tio x ponatur minor pyramide y: &longs;it alter conus æque al­<lb/> tus, uel altera coni portio X ip&longs;i pyramidi y æqualis. </s> <s id="s.000360">erit <lb/> eius ba&longs;is circulus, uel ellip&longs;is maior circulo, uel ellip&longs;i x, <lb/> quorum exce&longs;&longs;us &longs;it &longs;pacium <foreign lang="greek">w.</foreign> Si igitur in circulo, uel eili­<lb/> p&longs;i X figura rectilinea de&longs;cribatur, ita ut portiones relictæ <lb/> &longs;int <foreign lang="greek">w</foreign> &longs;pacio minores, ciu&longs;modi figura adhuc maior erit cir <lb/> culo, uel ellip&longs;i x, hoc e&longs;t figura rectilinea y. </s> <s id="s.000361">& pyramis in <lb/> ca con&longs;tituta minor cono, uel coni portione X, hoc e&longs;t mi­<lb/> nor pyramide y. </s> <s id="s.000362">e&longs;t ergo ut X figura rectilinea ad figuram <lb/> rectilineam y, ita pyramis X ad pyramidem y. </s> <s id="s.000363">quare cum <lb/> figura rectilinea X &longs;it maior figura y: erit & pyramis X py­<lb/> ramide y maior. </s> <s id="s.000364">&longs;ed erat minor; quod rur&longs;us fieri non po­<lb/> te&longs;t. </s> <s id="s.000365">non e&longs;t igitur conus, uel coni portio x neque maior, <lb/> neque minor pyramide y. </s> <s id="s.000366">ergo ip&longs;i nece&longs;&longs;ario e&longs;t æqualis. </s> <lb/> <s id="s.000367">Itaque quoniam ut conus ad conum, uel coni portio ad co <pb pagenum="16" xlink:href="023/01/039.jpg"/><figure id="id.023.01.039.1.jpg" xlink:href="023/01/039/1.jpg"/><lb/> ni portionem, ita e&longs;t cylindrus ad cylindrum, uel cylin­<lb/> dri portio ad cylindri portionem: & ut pyramis ad pyra­<lb/> midem, ita pri&longs;ma ad pri&longs;ma, cum eadem &longs;it ba&longs;is, & æqua <lb/> lis altitudo; erit cylindrus uel cylindri portio x pri&longs;ma­<lb/> ti y æqualis. </s> <s id="s.000368"><expan abbr="e&longs;tq;">e&longs;tque</expan> ut &longs;pacium gh ad &longs;pacium x, ita cylin­<lb/> drus, uel cylindri portio ce ad cylindrum, uel cylindri por­<lb/> tionem x. </s> <s id="s.000369">Con&longs;tat igitur cylindrum uel cylindri <expan abbr="portion&etilde;">portionem</expan> <lb/> c e, ad pri&longs;ma y, quippe cuius ba&longs;is e&longs;t figura rectilinea in <lb/> <arrow.to.target n="marg47"/><lb/> &longs;pacio gh de&longs;cripta, eandem proportionem habere, quam <lb/> &longs;pacium gh habet ad &longs;pacium x, hoc e&longs;t ad dictam figuram. </s> <lb/> <s id="s.000370">quod demon&longs;trandum fuerat.</s> </p> <p type="margin"> <s id="s.000371"><margin.target id="marg46"/>6. duode<lb/> cimi.</s> </p> <p type="margin"> <s id="s.000372"><margin.target id="marg47"/>7. quinti</s> </p> <p type="head"> <s id="s.000373">THEOREMA IX. PROPOSITIO IX.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000374">Si pyramis &longs;ecetur plano ba&longs;i æquidi&longs;tante; &longs;e­<lb/> ctio erit figura &longs;imilis ei, quæ e&longs;t ba&longs;is, centrum <lb/> grauitatis in axe habens.</s> </p> <pb xlink:href="023/01/040.jpg"/> <p type="main"> <s id="s.000375">SIT pyramis, cuius ba&longs;is triangulum abc; axis dc: & <lb/> &longs;ecetur plano ba&longs;i æquidi&longs;tante; quod <expan abbr="&longs;ection&etilde;">&longs;ectionem</expan> faciat fgh; <lb/> <expan abbr="occurratq;">occurratque</expan> axi in puncto k. Dico fgh triangulum e&longs;&longs;e, ip&longs;i <lb/> abc &longs;imile; cuius grauitatis centrum e&longs;t K. <expan abbr="Quoniã">Quoniam</expan> enim <lb/> duo plana æquidi&longs;tantia abc, fgh &longs;ecantur à plano abd; <lb/> communes eorum &longs;ectiones ab, fg æquidi&longs;tantes erunt: & <lb/> eadem ratione æquidi&longs;tantes ip&longs;æ bc, gh: & ca, hf. </s> <s id="s.000376">Quòd <lb/> cum duæ lineæ fg, gh, duabus ab, bc æquidi&longs;tent, nec <lb/> &longs;int in eodem plano; angulus ad g æqualis e&longs;t angulo ad <lb/> b. </s> <s id="s.000377">& &longs;imiliter angulus ad h angulo ad c: <expan abbr="angulusq;">angulusque</expan> ad fci, <lb/> qui ad a e&longs;t æqualis. </s> <s id="s.000378">triangulum igitur fgh &longs;imile e&longs;t tri­<lb/> angulo abc. <!-- KEEP S--></s> <s id="s.000379">Atuero punctum k centrum e&longs;&longs;e grauita­<lb/> tis trianguli fgh hoc modo o&longs;tendemus. </s> <s id="s.000380">Ducantur pla­<lb/> na per axem, & per lineas da, db, dc: erunt communes &longs;e­<lb/> ctiones fK, ae æquidi&longs;tantes: <expan abbr="pariterq;">pariterque</expan> kg, eb; & kh, ec: <lb/> quare angulus kfh angulo eac; & angulus kfg ip&longs;i eab <lb/> <figure id="id.023.01.040.1.jpg" xlink:href="023/01/040/1.jpg"/><lb/> e&longs;t æqualis. </s> <s id="s.000381">Eadem ratione <lb/> anguli ad g angulis ad b: & <lb/> anguli ad h iis, qui ad c æ­<lb/> quales erunt. </s> <s id="s.000382">ergo puncta <lb/> eK in triangulis abc, fgh <lb/> &longs;imiliter &longs;unt po&longs;ita, per &longs;e­<lb/> xtam po&longs;itionem Archime­<lb/> dis in libro de centro graui­<lb/> tatis planorum. </s> <s id="s.000383">Sed cum e <lb/> &longs;it centrum grauitatis trian<lb/> guli abc, erit ex undecima <lb/> propo&longs;itione eiu&longs;dem libri, <lb/> & K trianguli fgh grauita<lb/> tis centrum. </s> <s id="s.000384">id quod demon&longs;trare oportebat. </s> <s id="s.000385">Non aliter <lb/> in ceteris pyramidibus, quod propo&longs;itum e&longs;t demon&longs;tra­<lb/> bitur.</s> </p> <pb pagenum="17" xlink:href="023/01/041.jpg"/> <p type="head"> <s id="s.000386">PROBLEMA I. PROPOSITIO X.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000387">DATA qualibet pyramide, fieri pote&longs;t, ut fi­<lb/> gura &longs;olida in ip&longs;a in &longs;cribatur, & altera <expan abbr="circũ&longs;cri-batur">circum&longs;cri­<lb/> batur</expan> ex pri&longs;matibus æqualem altitudinem <expan abbr="ha-b&etilde;tibus">ha­<lb/> bentibus</expan>, ita ut circum&longs;cripta in&longs;criptam excedat <lb/> magnitudine, quæ minor &longs;it <expan abbr="quacũque">quacunque</expan> &longs;olida ma<lb/> gnitudine propo&longs;ita.</s> </p> <figure id="id.023.01.041.1.jpg" xlink:href="023/01/041/1.jpg"/> <p type="main"> <s id="s.000388">Sit pyramis, cuius ba&longs;is <lb/> <expan abbr="triangulũ">triangulum</expan> abc; axis de. </s> <lb/> <s id="s.000389"><expan abbr="Sitq;">Sitque</expan> pri&longs;ma, quod <expan abbr="eand&etilde;">eandem</expan> <lb/> ba&longs;im habeat, & axem eun<lb/> dem. </s> <s id="s.000390">Itaque hoc pri&longs;ma­<lb/> te continenter &longs;ecto bifa­<lb/> riam, plano ba&longs;i <expan abbr="æquidi&longs;tã">æquidi&longs;tan</expan><lb/> te, relinquetur <expan abbr="tãdem">tandem</expan> pri&longs;<lb/> ma quoddam minus pro­<lb/> po&longs;ita magnitudine: quod <lb/> quidem ba&longs;im eandem ha<lb/> beat, quam pyramis, & a­<lb/> xem ef. </s> <s id="s.000391">diuidatur de in <lb/> partes æquales ip&longs;i ef in <lb/> punctis ghklmn: & per <lb/> diui&longs;iones plana <expan abbr="ducãtur">ducantur</expan>: <lb/> quæ ba&longs;ibus æquidi&longs;tent, <lb/> erunt &longs;ectiones, triangula <lb/> ip&longs;i abc &longs;imilia, ut proxi­<lb/> me o&longs;tendimus. </s> <s id="s.000392">ab uno <lb/> quoque <expan abbr="aut&etilde;">autem</expan> horum trian<lb/> gulorum duo pri&longs;mata <expan abbr="cõ">con</expan><lb/> &longs;truantur; unum quidem <lb/> ad partes e; alterum ad <pb xlink:href="023/01/042.jpg"/>partes d. <!-- KEEP S--></s> <s id="s.000393">in pyramide igitur in&longs;cripta erit quædam figura, <lb/> ex pri&longs;matibus æqualem altitudinem habentibus <expan abbr="cõ&longs;tans">con&longs;tans</expan>, <lb/> ad partes e: & altera circum&longs;cripta ad partes d. <!-- KEEP S--></s> <s id="s.000394">Sed unum­<lb/> quodque eorum pri&longs;matum, quæ in figura in&longs;cripta conti­<lb/> nentur, æquale e&longs;t pri&longs;mati, quod ab eodem fit triangulo in <lb/> figura circum&longs;cripta: nam pri&longs;ma pq pri&longs;mati po e&longs;t æ­<lb/> quale; pri&longs;ma st æquale pri&longs;mati sr; pri&longs;ma xy pri&longs;mati <lb/> xu; pri&longs;ma <foreign lang="greek">hq</foreign> pri&longs;mati <foreign lang="greek">h</foreign>z; pri&longs;ma <foreign lang="greek">mn</foreign> pri&longs;mati <foreign lang="greek">ml;</foreign> pri&longs;­<lb/> ma <foreign lang="greek">rs</foreign> pri&longs;mati <foreign lang="greek">rp;</foreign> & pri&longs;ma <foreign lang="greek">fx</foreign> pri&longs;mati <foreign lang="greek">ft</foreign> æquale. </s> <s id="s.000395">re­<lb/> linquitur ergo, ut circum&longs;cripta figura exuperet <expan abbr="in&longs;criptã">in&longs;criptam</expan> <lb/> pri&longs;mate, quod ba&longs;im habet abc triangulum, & axem ef. </s> <lb/> <s id="s.000396">Illud uero minus e&longs;t &longs;olida magnitudine propo&longs;ita. </s> <s id="s.000397"><expan abbr="Ead&etilde;">Eadem</expan> <lb/> ratione in&longs;cribetur, & circum&longs;cribetur &longs;olida figura in py­<lb/> ramide, quæ quadrilateram, uel <expan abbr="plurilaterã">plurilateram</expan> ba&longs;im habeat.</s> </p> <p type="head"> <s id="s.000398">PROBLEMA II. PROPOSITIO XI.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000399">DATO cono, fieri pote&longs;t, ut figura &longs;olida in­<lb/> &longs;cribatur, & altera circum&longs;cribatur ex cylindris <lb/> æqualem habentibus altitudinem, ita ut circum­<lb/> &longs;cripta &longs;uperet in&longs;criptam, magnitudine, quæ &longs;o­<lb/> lida magnitudine propo&longs;ita &longs;it minor.</s> </p> <p type="main"> <s id="s.000400">SIT conus, cuius axis bd: & &longs;ecetur plano per axem <lb/>ducto, 'ut &longs;ectio &longs;it triangulum abc: <expan abbr="intelligaturq;">intelligaturque</expan> cylin­<lb/> drus, qui ba&longs;im eandem, & eundem axem habeat. </s> <s id="s.000401">Hoc igi­<lb/> tur cylindro continenter bifariam &longs;ecto, relinquetur cylin<lb/> drus minor &longs;olida magnitudine propo&longs;ita. </s> <s id="s.000402">Sit autem is cy<lb/> lindrus, qui ba&longs;im habet circulum circa diametrum ac, & <lb/> axem de. </s> <s id="s.000403">Itaque diuidatur bd in partes æquales ip&longs;i de <lb/> in punctis fghKlm: & per ea ducantur plana conum &longs;e­<lb/> cantia; quæ ba&longs;i æquidi&longs;tent. </s> <s id="s.000404">erunt &longs;ectiones circuli, cen­<lb/> tra in axi habentes, ut in primo libro conicorum, propo&longs;i- <pb pagenum="18" xlink:href="023/01/043.jpg"/>tione quarta Apollonius demon&longs;trauit. </s> <s id="s.000405">Si igitur à &longs;ingu­<lb/> lis horum circulorum, duo cylindri fiant; unus quidem ad <lb/> ba&longs;is partes; alter ad partes uerticis: in&longs;cripta erit in co­<lb/> no &longs;olida quædam figura, & altera circum&longs;cripta ex cylin­<lb/> dris æqualem altitudinem habentibus con&longs;tans; quorum <lb/> <figure id="id.023.01.043.1.jpg" xlink:href="023/01/043/1.jpg"/><lb/> unu&longs;qui&longs;que, qui in <lb/> figura in&longs;cripta con­<lb/> tinetur æqualis e&longs;t ei, <lb/> qui ab eodem fit cir­<lb/> culo in figura <expan abbr="circũ-&longs;cripta">circum­<lb/> &longs;cripta</expan>. </s> <s id="s.000406">Itaque cylin<lb/> drus op æqualis e&longs;t <lb/> cylindro on; cylin­<lb/> drus rs <expan abbr="cylĩdro">cylindro</expan> rq.</s> <lb/> <s id="s.000407"> cylindrus ux cylin­<lb/> dro ut e&longs;t æqualis; <lb/> & alii aliis &longs;imiliter. </s> <lb/> <s id="s.000408">quare con&longs;tat <expan abbr="circũ-&longs;criptam">circum­<lb/> &longs;criptam</expan> figuram &longs;u­<lb/> perare in&longs;criptam cy<lb/> lindro, cuius ba&longs;is e&longs;t <lb/> circulus circa diametrum ac, & axis de. </s> <s id="s.000409">atque hic e&longs;t mi­<lb/> nor &longs;olida magnitudine propo&longs;ita.</s> </p> <p type="head"> <s id="s.000410">PROBLEMA III. PROPOSITIO XII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000411">DATA coni portione, pote&longs;t &longs;olida quædam <lb/>figura in&longs;cribi, & altera circum&longs;cribi ex cylindri <lb/> portionibus æqualem altitudinem habentibus; <lb/> ita ut circum&longs;cripta in&longs;criptam exuperet, magni <lb/> tudine, quæ minor fit &longs;olida magnitudine pro­<lb/> po&longs;ita.</s> </p> <pb xlink:href="023/01/044.jpg"/> <p type="main"> <s id="s.000412">Figuram cuiu&longs;modi, & in&longs;cribemus, & <expan abbr="circũ&longs;cribemus">circum&longs;cribemus</expan>, ita <lb/> ut in cono dictum e&longs;t.</s> </p> <figure id="id.023.01.044.1.jpg" xlink:href="023/01/044/1.jpg"/> <p type="head"> <s id="s.000413">PROBLEMA IIII. PROPOSITIO XIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000414">DATA &longs;phæræ portione, quæ dimidia &longs;phæ­<lb/> ra maior non &longs;it, pote&longs;t &longs;olida quædam portio in­<lb/> &longs;cribi & altera circum&longs;cribi ex cylindris æqualem <lb/> altitudinem habentibus, ita ut circum&longs;cripta in­<lb/> &longs;criptam excedat magnitudine, quæ &longs;olida ma­<lb/> gnitudine propo&longs;ita &longs;it minor.</s> </p> <p type="main"> <s id="s.000415">HOC etiam eodem pror&longs;us modo &longs;iet: atque ut ab <lb/>Archimede traditum e&longs;t in conoidum, & &longs;phæroidum por<lb/> tionibus, propo&longs;itione uige&longs;imaprima libri de conoidi­<lb/> bus, & &longs;phæroidibus.</s> </p> <pb pagenum="19" xlink:href="023/01/045.jpg"/> <figure id="id.023.01.045.1.jpg" xlink:href="023/01/045/1.jpg"/> <p type="head"> <s id="s.000416">THEOREMA X. PROPOSITIO XIIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000417">Cuiuslibet pyramidis, & cuiuslibet coni, uel <lb/> coni portionis, centrum grauitatis in axe <expan abbr="cõ&longs;i&longs;tit">con&longs;i&longs;tit</expan>.</s> </p> <p type="main"> <s id="s.000418">SIT pyramis, cuius ba&longs;is triangulum abc: & axis de. </s> <lb/> <s id="s.000419">Dico in linea de ip&longs;ius grauitatis centrum ine&longs;&longs;e. </s> <s id="s.000420">Si enim <lb/> fieri pote&longs;t, &longs;it centrum f: & ab f ducatur ad ba&longs;im pyrami<lb/> dis linea fg, axi æquidi&longs;tans: <expan abbr="iunctaq;">iunctaque</expan> eg ad latera trian­<lb/> guli abc producatur in h. </s> <s id="s.000421">quam uero proportionem ha­<lb/> bet linea he ad eg, habeat pyramis ad aliud &longs;olidum, in <lb/> quo K: <expan abbr="in&longs;cribaturq;">in&longs;cribaturque</expan> in pyramide &longs;olida figura, & altera cir<lb/> cum&longs;cribatur ex pri&longs;matibus æqualem habentibus altitu­<lb/> dinem, ita ut circum&longs;cripta in&longs;criptam exuperet magnitu­<lb/> dine, quæ &longs;olido k &longs;it minor. </s> <s id="s.000422">Et quoniam in pyramide pla<lb/> num ba&longs;i æquidi&longs;tans ductum &longs;ectionem facit figuram &longs;i­<lb/> milem ei, quæ e&longs;t ba&longs;is; <expan abbr="centrumq;">centrumque</expan> grauitatis in axe haben<lb/> tem: erit pri&longs;matis st grauitatis <expan abbr="centrũ">centrum</expan> in linea rq ; <lb/> matis ux centrum in linea qp, pri&longs;matis yz in linea po; <lb/> pri&longs;matis <foreign lang="greek">hq</foreign> in linea on; pri&longs;matis <foreign lang="greek">lm</foreign> in linea nm; pri&longs;­<lb/> matis <foreign lang="greek">np</foreign> in ml; & denique pri&longs;matis <foreign lang="greek">rs</foreign> in le. </s> <s id="s.000423">quare to­ <pb xlink:href="023/01/046.jpg"/>tius figuræ in&longs;criptæ centrum grauitatis e&longs;t in linea re: <lb/> <figure id="id.023.01.046.1.jpg" xlink:href="023/01/046/1.jpg"/>quod &longs;it <foreign lang="greek">t</foreign>: <expan abbr="iũ">iun</expan>­<lb/> ctaque <foreign lang="greek">t</foreign>f, & <lb/> producta, à <lb/> puncto h du­<lb/> catur linea a­<lb/> xi pyramidis <lb/> æquidi&longs;tans, <lb/> quæ <expan abbr="cũ">cum</expan> linea <lb/> <foreign lang="greek">t</foreign>f conueniat <lb/> in <foreign lang="greek">f</foreign>.</s> <s id="s.000424">habebit <lb/> <foreign lang="greek">ft</foreign> ad <foreign lang="greek">t</foreign>f ean­<lb/> dem propor­<lb/> tionem, <expan abbr="quã">quam</expan> <lb/> he ad eg. <lb/> </s> </p> <p> <s id="s.000425">Quoniam igi<lb/> tur exce&longs;&longs;us, <lb/> quo <expan abbr="circũ">circum</expan>&longs;cri<lb/> pta figura in­<lb/> &longs;criptam &longs;upe<lb/> rat, minor e&longs;t <lb/> &longs;olido <foreign lang="greek">x</foreign>; py­<lb/> ramis ad eun­<lb/> <expan abbr="d&etilde;">dem</expan> <expan abbr="exce&longs;&longs;ũ">exce&longs;&longs;um</expan> ma<lb/> ioré propor­<lb/> tioné habet, <lb/> quàm ad K &longs;o<lb/> lidum: uideli<lb/> cet maiorem, <lb/> quàm linea h<lb/> e ad eg; hoc <lb/> e&longs;t quàm <foreign lang="greek">ft</foreign> <lb/> ad <foreign lang="greek">t</foreign>f: & propterea multo maiorem habet ad partem ex­<lb/> ce&longs;&longs;us, quæ intra pyrimidem comprehenditur. </s> <s id="s.000426">Itaque ha­ <pb pagenum="20" xlink:href="023/01/047.jpg"/>beat eam, quam <foreign lang="greek">xt</foreign> ad <foreign lang="greek">t</foreign>f erit diuidendo ut <foreign lang="greek">x</foreign>f ad f<foreign lang="greek">t</foreign>, ita fi<lb/> gura &longs;olida in&longs;cripta ad partem exce&longs;&longs;us, quæ e&longs;t intra pyra<lb/> midem. </s> <s id="s.000427">Cum ergo à pyramide, cuius grauitatis <expan abbr="ceũtrum">centrum</expan> e&longs;t <lb/> punctum f, &longs;olida figura in&longs;cripta auferatur, cuius <expan abbr="centrũtrum">centrum</expan> <lb/> <foreign lang="greek">t</foreign>: reliqua magnitudinis con&longs;tantis ex parte exce&longs;&longs;us, quæ <lb/> e&longs;t intra pyramidem, centrum grauitatis erit in linea <foreign lang="greek">t</foreign>f <lb/> producta, & in puncto <foreign lang="greek">x</foreign>. </s> <s id="s.000428">quod fieri non pote&longs;t. </s> <s id="s.000429">Sequitur <lb/> igitur, ut centrum grauitatis pyramidis in linea de; hoc <lb/> e&longs;t in eius axe con&longs;i&longs;tat.</s> </p> <p> <s id="s.000430">Sit conus, uel coni portio, cuius axis bd: & &longs;ecetur plano <lb/> per axem, ut &longs;ectio &longs;it triangulum abc. </s> <s id="s.000431">Dico centrum gra<lb/> uitatis ip&longs;ius e&longs;&longs;e in linea bd. </s> <s id="s.000432">Sit enim, &longs;i fieri pote&longs;t, <expan abbr="centrũ">centrum</expan> <lb/> <figure id="id.023.01.047.1.jpg" xlink:href="023/01/047/1.jpg"/> e: <expan abbr="perq;">perque</expan> e ducatur ef axi æquidi&longs;tans: & quam propor­<lb/> tionem habet cd ad df, habeat conus, uel coni portio ad <lb/> &longs;olidum g. </s> <s id="s.000433">in&longs;cribatur ergo in cono, uel coni portione &longs;oli <pb xlink:href="023/01/048.jpg"/>da figura, & altera circum&longs;cribatur ex cylindris, uel cylin­<lb/> dri portionibus, &longs;icuti dictum e&longs;t, ita ut exce&longs;&longs;us, quo figu­<lb/> ra circum&longs;cripta in&longs;criptam &longs;uperat, &longs;it &longs;olido g minor. </s> <lb/> <s id="s.000434">Itaque centrum grauitatis cylindri, uel cylindri portionis <lb/> qr e&longs;t in linea po; cylindri, uel cylindri portionis st cen­<lb/> trum in linea on; centrum ux in linea nm; yz in mb; <foreign lang="greek">nq</foreign><lb/> in lk; <foreign lang="greek">lm</foreign> in kh; & denique <foreign lang="greek">vp</foreign> centrum in hd. <!-- KEEP S--></s> <s id="s.000435">ergo figu­<lb/> <figure id="id.023.01.048.1.jpg" xlink:href="023/01/048/1.jpg"/><lb/> ræ in&longs;criptæ centrum e&longs;t in linea pd. <!-- KEEP S--></s> <s id="s.000436">Sit autem <foreign lang="greek">r</foreign>: & iun­<lb/> cta <foreign lang="greek">r</foreign>e protendatur, ut cum linea, quæ à <expan abbr="pũcto">puncto</expan> c ducta &longs;ue­<lb/> rit axi æquidi&longs;tans, conueniat in <foreign lang="greek">s.</foreign> erit <foreign lang="greek">s r</foreign> ad <foreign lang="greek">r</foreign>e, ut cd <lb/> ad df: & conus, &longs;eu coni portio ad exce&longs;&longs;um, quo circum­<lb/> &longs;cripta figura in&longs;criptam &longs;uperat, habebit maiorem pro­<lb/> portionem, quàm <foreign lang="greek">tr</foreign> ad <foreign lang="greek">r</foreign>e. </s> <s id="s.000437">ergo ad partem exce&longs;&longs;us, quæ <lb/> intra ip&longs;ius &longs;uperficiem comprehenditur, multo maiorem <lb/> proportionem habebit. </s> <s id="s.000438">habeat eam, quam <foreign lang="greek">tr</foreign> ad <foreign lang="greek">r</foreign>e. </s> <s id="s.000439">erit <pb pagenum="21" xlink:href="023/01/049.jpg"/>diuidendo figura &longs;olida in&longs;cripta ad dictam exce&longs;&longs;us par­<lb/> tem, ut <foreign lang="greek">te</foreign> ad c<foreign lang="greek">p.</foreign> & quoniam à cono, &longs;eu coni portione, <lb/> cuius grauitatis centrum e&longs;t e, aufertur figura in&longs;cripta, <lb/> cuius centrum <foreign lang="greek">r:</foreign> re&longs;iduæ magnitudinis compo&longs;itæ cx par <lb/> te exce&longs;&longs;us, quæ intra coni, uel coni portionis &longs;uperficiem <lb/> continetur, centrum grauitatis erit in linea e protracta, <lb/> atque in puncto t. </s> <s id="s.000440">quod e&longs;t ab&longs;urdum. </s> <s id="s.000441"><expan abbr="cõ&longs;tat">con&longs;tat</expan> ergo <expan abbr="centrũ">centrum</expan> <lb/> grauitatis coni, uel coni portionis, e&longs;&longs;e in axe bd: quod de <lb/> mon&longs;trandum propo&longs;uimus.</s> </p> <p type="head"> <s id="s.000442">THEOREMA XI. PROPOSITIO XV.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000443">Cuiuslibet portionis &longs;phæræ uel &longs;phæroidis, <lb/> quæ dimidia maior non &longs;it: <expan abbr="item&qacute;;">itemque</expan> cuiuslibet por<lb/> tionis conoidis, uel ab&longs;ci&longs;&longs;æ plano ad axem recto, <lb/> uel non recto, centrum grauitatis in axe con­<lb/> &longs;i&longs;tit.</s> </p> <p type="main"> <s id="s.000444">Demon&longs;tratio &longs;imilis erit ei, quam &longs;upra in cono, uel co<lb/> ni portione attulimus, ne toties eadem fru&longs;tra iterentur.</s> </p> <figure id="id.023.01.049.1.jpg" xlink:href="023/01/049/1.jpg"/> <pb xlink:href="023/01/050.jpg"/> <p type="head"> <s id="s.000445">THEOREMA XII. PROPOSITIO XVI.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000446">In &longs;phæra, & &longs;phæroide idem e&longs;t grauitatis, & <lb/> figuræ centrum.</s> </p> <p type="main"> <s id="s.000447">Secetur &longs;phæra, uel &longs;phæroides plano per axem ducto; <lb/> quod &longs;ectionem faciat circulum, uel ellip&longs;im abcd, cuius <lb/> diameter, & &longs;phæræ, uel &longs;phæroidis axis db; & centrum e. </s> <lb/> <s id="s.000448">Dico e grauitatis etiam centrum e&longs;&longs;e. </s> <s id="s.000449">&longs;ecetur enim altero <lb/> plano per e, ad planum &longs;ecans recto, cuius &longs;ectio &longs;it circu­<lb/> lus circa diametrum ac. </s> <s id="s.000450">erunt adc, abc dimidiæ portio­<lb/> nes &longs;phæræ, uel &longs;phæroidis. </s> <s id="s.000451">& quoniam portionis adc gra<lb/> uitatis centrum e&longs;i in linea d, & centrum portionis abc in <lb/> ip&longs;a be; totius &longs;phæræ, uel &longs;phæroidis grauitatis centrum <lb/>in axe db con&longs;i&longs;tet, Quòd &longs;i portionis adc centrum graui <lb/> tatis ponatur e&longs;&longs;e f & fiat ip&longs;i fe æqualis eg: <expan abbr="punctũ">punctum</expan> g por<lb/> <figure id="id.023.01.050.1.jpg" xlink:href="023/01/050/1.jpg"/><lb/> <arrow.to.target n="marg48"/><lb/> tionis abc centrum erit. </s> <s id="s.000452">&longs;olidis enim figuris &longs;imilibus & <lb/> æqualibus inter &longs;e aptatis, & centra grauitatis ip&longs;arum in­<lb/> <arrow.to.target n="marg49"/><lb/> ter se aptentur nece&longs;&longs;e e&longs;t. </s> <s id="s.000453">ex quo fit, ut magnitudinis, quæ <lb/> ex utilique <expan abbr="cõ&longs;lat">con&longs;tat</expan>, hoc e&longs;t ip&longs;ius &longs;phæræ, uel &longs;phæroidis gra<lb/> uitatis centrum &longs;it in medio lineæ fg uidelicet in e. </s> <s id="s.000454">Sphæ­<lb/> ræ igitur, uel &longs;phæroidis grauitatis centrum e&longs;t idem, quod <lb/> centrum figuræ.</s> </p> <pb pagenum="22" xlink:href="023/01/051.jpg"/> <p type="margin"> <s id="s.000455"><margin.target id="marg48"/>per 2. pe­<lb/> titionem</s> </p> <p type="margin"> <s id="s.000456"><margin.target id="marg49"/>4 Archi­<lb/> medis.</s> </p> <p type="main"> <s id="s.000457">Ex demon&longs;tratis per&longs;picue apparet, portioni <lb/> &longs;phæræ uel &longs;phæroidis, quæ dimidia maior e&longs;t, <expan abbr="c&etilde;">cen</expan><lb/> trum grauitatis in axe con&longs;i&longs;tere.</s> </p> <figure id="id.023.01.051.1.jpg" xlink:href="023/01/051/1.jpg"/> <p type="main"> <s id="s.000458">Data enim <lb/> qualibet maio<lb/> ri <expan abbr="portiõe">portione</expan>, quo <lb/> <expan abbr="niã">niam</expan> totius &longs;phæ<lb/> ræ, uel &longs;phæroi<lb/> dis grauitatis <lb/> centrum e&longs;t in <lb/> axe; e&longs;t autem <lb/> & in axe cen­<lb/> trum portio­<lb/> nis minoris: <lb/> reliquæ portionis uidelicet maioris centrum in axe nece&longs;­<lb/> &longs;ario con&longs;i&longs;tet.</s> </p> <p type="head"> <s id="s.000459">THEOREMA XIII. PROPOSITIO XVII.<!-- KEEP S--></s> </p> <figure id="id.023.01.051.2.jpg" xlink:href="023/01/051/2.jpg"/> <p type="main"> <s id="s.000460">Cuiuslibet pyramidis <expan abbr="triãgularem">trian<lb/> gularem</expan> ba&longs;im <expan abbr="hab&etilde;tis">habentis</expan> gra<lb/> uitatis centrum e&longs;t in pun­<lb/> cto, in quo ip&longs;ius axes con­<lb/> ueniunt.</s> </p> <p type="main"> <s id="s.000461">Sit pyramis, cuius ba&longs;is trian<lb/> gulum abc, axis de: <expan abbr="&longs;itq;">&longs;itque</expan> trian<lb/> guli bdc grauitatis centrum f: <lb/> & iungatur a &longs;. </s> <s id="s.000462">erit & af axis eiu&longs;<lb/> dem pyramidis ex tertia diffini­<lb/> tione huius. </s> <s id="s.000463">Itaque quoniam centrum grauitatis e&longs;t in <lb/> axe de; e&longs;t autem & in axe af; &qgrave;uod proxime demon&longs;traui <pb xlink:href="023/01/052.jpg"/>mus: erit utique grauitatis centrum pyramidis punctum <lb/> g. <!-- REMOVE S-->in quo &longs;cilicet ip&longs;i axes conueniunt.</s> </p> <p type="head"> <s id="s.000464">THEOREMA XIIII. PROPOSITIO XVIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000465">SI &longs;olidum parallelepipedum &longs;ecetur plano <lb/> ba&longs;ibus æquidi&longs;tante; erit &longs;olidum ad &longs;olidum, <lb/> &longs;icut altitudo ad altitudinem, uel &longs;icut axis ad <lb/> axem.</s> </p> <figure id="id.023.01.052.1.jpg" xlink:href="023/01/052/1.jpg"/> <p type="main"> <s id="s.000466">Sit &longs;olidum parallelepipe<lb/> dum abcdefgh, cuius axis <lb/> kl: <expan abbr="&longs;eceturq;">&longs;eceturque</expan> plano ba&longs;ibus <lb/> æquidi&longs;tante, quod faciat <lb/> &longs;ectionem mnop; & axi in <lb/> puncto q occurrat. </s> <s id="s.000467">Dico <lb/> &longs;olidum gm ad &longs;olidum mc <lb/> eam proportionem habere, <lb/> quam altitudo &longs;olidi gm ha­<lb/> bet ad &longs;olidi mc altitudi­<lb/> nem; uel quam axis kq ad <lb/> axem ql. <!-- KEEP S--></s> <s id="s.000468">Si enim axis Kl ad <lb/> ba&longs;is planum &longs;it perpendicu<lb/> <figure id="id.023.01.052.2.jpg" xlink:href="023/01/052/2.jpg"/><lb/> laris, & linea gc, quæ ex quin<lb/> ta huius ip&longs;i kl æquidi&longs;tat, <lb/> perpendicularis erit ad <expan abbr="id&etilde;">idem</expan> <lb/> planum, & &longs;olidi altitudi­<lb/> <arrow.to.target n="marg50"/><lb/> nem dimetietur. </s> <s id="s.000469">Itaque &longs;o­<lb/> lidum gm ad &longs;olidum mc <lb/> eam proportionem habet, <lb/> quam parallelogramm<expan abbr="ũ">um</expan> gn <lb/> ad parallelogrammum nc, <lb/> <arrow.to.target n="marg51"/><lb/> hoc e&longs;t quam linea go, quæ <pb pagenum="23" xlink:href="023/01/053.jpg"/>e&longs;t &longs;olidi gm altitudo ad oe altitudinem &longs;olidi mc, uel <expan abbr="quã">quam</expan> <lb/> axis kq ad ql axem. </s> <s id="s.000470">Si uero axis kl non &longs;it perpendicularis <lb/> ad planum ba&longs;is; ducatur a puncto k ad idem planum per<lb/> pendicularis kr, <expan abbr="occurr&etilde;s">occurrens</expan> plano mnop in s. </s> <s id="s.000471">&longs;imiliter <expan abbr="de-mõ&longs;trabimus">de­<lb/> mon&longs;trabimus</expan> &longs;olidum gm ad <expan abbr="&longs;olidũ">&longs;olidum</expan> mc ita e&longs;&longs;e, ut axis kq <lb/> ad axem ql. </s> <s id="s.000472">Sed ut Kq ad ql, ita ks altitudo ad altitudi­<lb/> <arrow.to.target n="marg52"/><lb/> nem sr; nam lineæ Kl, Kr à planis æquidi&longs;tantibus in ea&longs;­<lb/> dem proportiones &longs;ecantur. </s> <s id="s.000473">ergo &longs;olidum gm ad &longs;olidum <lb/> mc <expan abbr="eand&etilde;">eandem</expan> proportionem habet, quam altitudo ad <expan abbr="altitudin&etilde;">altitu<lb/> dinem</expan>, uel quam axis ad axem. </s> <s id="s.000474">quod <expan abbr="demõ&longs;trare">demon&longs;trare</expan> oportebat.</s> </p> <p type="margin"> <s id="s.000475"><margin.target id="marg50"/>25 undeci<lb/> mi.</s> </p> <p type="margin"> <s id="s.000476"><margin.target id="marg51"/><expan abbr="&longs;extĩ">&longs;extim</expan>.</s> </p> <p type="margin"> <s id="s.000477"><margin.target id="marg52"/>17. unde­<lb/> cimi</s> </p> <p type="head"> <s id="s.000478">THEOREMA XV. PROPOSITIO XIX.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000479">Solida parallelepipeda in eadem ba&longs;i, uel in <lb/> æqualibus ba&longs;ibus con&longs;tituta eam inter &longs;e propor<lb/> tionem habent, quam altitudines: & &longs;i axes ip&longs;o­<lb/> rum cum ba&longs;ibus æquales angulos contineant, <lb/> eam quoque, quam axes proportionem <expan abbr="habebũt">habebunt</expan>.</s> </p> <p type="main"> <s id="s.000480">Sint &longs;olida parallelepipeda in <expan abbr="ead&etilde;">eadem</expan> ba&longs;i <expan abbr="cõ&longs;tituta">con&longs;tituta</expan> abcd, <lb/> abef: & &longs;it &longs;olidi abcd altitudo minor: producatur au­<lb/> tem planum cd adeo, ut &longs;olidum abef &longs;ecet; cuius &longs;ectio <lb/> <figure id="id.023.01.053.1.jpg" xlink:href="023/01/053/1.jpg"/><lb/> <arrow.to.target n="marg53"/><lb/> &longs;it gh. </s> <s id="s.000481"><expan abbr="erũt">erunt</expan> &longs;oli <lb/> da abcd, abgh <lb/> in eadem ba&longs;i, <lb/> & æquali altitu<lb/> dine inter &longs;e æ­<lb/> qualia. </s> <s id="s.000482"><expan abbr="Quoniã">Quoniam</expan> <lb/> igitur &longs;olidum <lb/> abef &longs;ecatur <lb/> plano ba&longs;ibus <lb/> <expan abbr="æquidi&longs;tãte">æquidi&longs;tante</expan>, erit <lb/> <arrow.to.target n="marg54"/><lb/> &longs;olidum ghef <lb/> adip&longs;um abgh <pb xlink:href="023/01/054.jpg"/>ut altitudo ad altitudinem: & componendo conuertendo <lb/> <arrow.to.target n="marg55"/><lb/> que &longs;olidum abgh, hoc e&longs;t &longs;olidum abcd ip&longs;i æquale, ad <lb/> &longs;olidum abef, ut altitudo &longs;olidi abcd ad &longs;olidi abef al­<lb/> titudinem.</s> </p> <p type="margin"> <s id="s.000483"><margin.target id="marg53"/>29. unde­<lb/> cimi</s> </p> <p type="margin"> <s id="s.000484"><margin.target id="marg54"/>18. huius</s> </p> <p type="margin"> <s id="s.000485"><margin.target id="marg55"/>7. quinti.</s> </p> <p type="main"> <s id="s.000486">Sint &longs;olida parallelopipeda ab, cd in æqualibus ba&longs;ibus <lb/> con&longs;tituta: <expan abbr="&longs;itq;">&longs;itque</expan> be altitudo &longs;olidi ab: & &longs;olidi cd altitudo <lb/> d f; quæ quidem maior &longs;it, quàm be. </s> <s id="s.000487">Dico &longs;olidum ab ad <lb/> &longs;olidum cd eandem habere proportionem, quam be ad <lb/> d f. </s> <s id="s.000488">ab&longs;cindatur enim à linea df æqualis ip&longs;i be, quæ &longs;it gf: <lb/> & per g ducatur planum &longs;ecans &longs;olidum cd; quod ba&longs;ibus <lb/> æquidi&longs;tet, <expan abbr="faciatq;">faciatque</expan> <expan abbr="&longs;ection&etilde;">&longs;ectionem</expan> hK. </s> <s id="s.000489">erunt &longs;olida ab, ck æque <lb/> <arrow.to.target n="marg56"/><lb/> <figure id="id.023.01.054.1.jpg" xlink:href="023/01/054/1.jpg"/><lb/> alta inter <lb/> &longs;e æqualia <lb/> <expan abbr="cũ">cum</expan> æqua­<lb/> les ba&longs;es <lb/> habeant. </s> <lb/> <s id="s.000490"><arrow.to.target n="marg57"/><lb/> Sed <expan abbr="&longs;olidũ">&longs;olidum</expan> <lb/> hd ad &longs;oli <lb/> dum cK <lb/> e&longs;t, ut alti<lb/> tudo dg <lb/> ad gf <expan abbr="alti­tudin&etilde;">alti­<lb/> tudinem</expan>; &longs;e<lb/> catur enim &longs;olidum cd plano ba&longs;i<lb/> <figure id="id.023.01.054.2.jpg" xlink:href="023/01/054/2.jpg"/><lb/> bus æquidi&longs;tante: & rur&longs;us <expan abbr="cõpo-nende">compo­<lb/> nende</expan>, <expan abbr="conuertendoq;">conuertendoque</expan> <expan abbr="&longs;olidũ">&longs;olidum</expan> ck <lb/> <arrow.to.target n="marg58"/><lb/> ad &longs;olidum cd, ut gf ad fd. <!-- KEEP S--></s> <s id="s.000491">ergo <lb/> &longs;olidum ab, quod e&longs;t æquale ip&longs;i <lb/> ck ad &longs;olidum cd eam proportio <lb/> nem habet, quam altitudo gf, hoc <lb/> e&longs;t be ad df altitudinem.</s> </p> <p type="margin"> <s id="s.000492"><margin.target id="marg56"/>31. unde<lb/> cimi</s> </p> <p type="margin"> <s id="s.000493"><margin.target id="marg57"/>18. huius</s> </p> <p type="margin"> <s id="s.000494"><margin.target id="marg58"/>7. quinti.</s> </p> <p type="main"> <s id="s.000495">Sint deinde &longs;olida parallelepipe<lb/> da ab, ac in eadem ba&longs;i; quorum <lb/>axes de, &longs; e cum ip&longs;a æquales angu<pb pagenum="24" xlink:href="023/01/055.jpg"/>los contineant. </s> <s id="s.000496">Dico &longs;olidum ab ad &longs;olidum ace idem ha<lb/> bere proportionem, quam axis de ad axem ef. </s> <s id="s.000497">Si enim <lb/> axes in eadem recta linea fuerint con&longs;tituti, hæc duo &longs;oli­<lb/> da, in unum, atque idem &longs;olidum conuenient. </s> <s id="s.000498">quare ex <lb/> iis, quæ proxime tradita &longs;unt, habebit &longs;olidum ab ad &longs;o­<lb/> lidum ac eandem proportionem, quam axis de ad ef <lb/> axem. </s> <s id="s.000499">Si uero axes non &longs;int in eadem recta linea, demittan<lb/> tur a punctis d, &longs; perpendiculares ad ba&longs;is planum, dg, fh: <lb/> & jungantur eg, eh. </s> <s id="s.000500">Quoniam igitur axes cum ba&longs;ibus <lb/> æquales angulos continent, erit deg angulus æqualis an­<lb/> <figure id="id.023.01.055.1.jpg" xlink:href="023/01/055/1.jpg"/><lb/> gulo feh: & &longs;unt <lb/> anguli ad gh re­<lb/> cti, quare & re­<lb/> liquus edg æqua<lb/> lis erit reliquo <lb/> efh: & triangu­<lb/> lum deg <expan abbr="triãgu-lo">triangu­<lb/> lo</expan> feh &longs;imile. </s> <s id="s.000501">er­<lb/> go gd ad de e&longs;t, <lb/> ut hf ad e: & per <lb/> mutando gd ad <lb/> hf, ut de ad cf. </s> <lb/> <figure id="id.023.01.055.2.jpg" xlink:href="023/01/055/2.jpg"/> <lb/> <s id="s.000502">Sed &longs;olidum ab <lb/> ad &longs;olidum ac <lb/> eandem propor­<lb/> tionem habet, <lb/> quam dg altitu­<lb/> do ad <expan abbr="altitudin&etilde;">altitudinem</expan> <lb/> fh. </s> <s id="s.000503">ergo & <expan abbr="ean-d&etilde;">ean­<lb/> dem</expan> habebit, <expan abbr="quã">quam</expan> <lb/> axis de ad ef <expan abbr="ax&etilde;">axem</expan></s> </p> <p type="main"> <s id="s.000504">Po&longs;tremo &longs;int <lb/> &longs;olidi parallepi<lb/> peda ab, cd in <pb xlink:href="023/01/056.jpg"/>æqualibus ba&longs;ibus, quorum axes cum ba&longs;ibus æquales an<lb/> gulos faciant. </s> <s id="s.000505">Dico &longs;olidum ab ad <expan abbr="&longs;olidũ">&longs;olidum</expan> cd ita e&longs;&longs;e, ut axis <lb/> ef ad axem gh: nam &longs;i axes ad planum ba&longs;is recti &longs;int, il­<lb/> lud per&longs;picue con&longs;tat: quoniam eadem linea, & axem & &longs;oli<lb/> di altitudinem determinabit. </s> <s id="s.000506">Si uero &longs;int inclinati, à pun­<lb/> ctis eg ad &longs;ubiectum planum perpendiculares ducantur <lb/> ek, gl: & iungantur fk, hl. <!-- KEEP S--></s> <s id="s.000507">rur&longs;us quoniam axes cum ba<lb/> &longs;ibus æquales faciunt angulos, eodem modo demon&longs;trabi<lb/> tur, triangulum efK triangulo ghl &longs;imile e&longs;&longs;e: & ek ad gl, <lb/> ut ef ad gh. </s> <s id="s.000508">Solidum autem ab ad &longs;olidum cd e&longs;t, ut <lb/> eK ad gl. <!-- KEEP S--></s> <s id="s.000509">ergo & ut axis ef ad axem gh. </s> <s id="s.000510">quæ omnia de<lb/> mon&longs;trare oportebat.</s> </p> <p type="main"> <s id="s.000511">Ex iis quæ demon&longs;trata &longs;unt, facile con&longs;tare <lb/> pote&longs;t, pri&longs;mata omnia & pyramides, quæ trian­<lb/>gulares ba&longs;es habent, &longs;iue in ei&longs;dem, &longs;iue in æqua<lb/> <arrow.to.target n="marg59"/><lb/> libus ba&longs;ibus con&longs;tituantur, eandem proportio­<lb/> nem habere, quam altitudines: & &longs;i axes cum ba<lb/> &longs;ibus æquales angulos contineant, &longs;imiliter ean­<lb/> dem, quam axes, habere proportionem: &longs;unt <lb/> <arrow.to.target n="marg60"/><lb/> enim &longs;olida parallelepipeda pri&longs;matum triangula<lb/> <arrow.to.target n="marg61"/><lb/> res ba&longs;es <expan abbr="habentiũ">habentium</expan> dupla; & pyramidum &longs;extupla.</s> </p> <p type="margin"> <s id="s.000512"><margin.target id="marg59"/>15. quinti</s> </p> <p type="margin"> <s id="s.000513"><margin.target id="marg60"/>28. unde­<lb/> cimi.</s> </p> <p type="margin"> <s id="s.000514"><margin.target id="marg61"/>7. duode­<lb/> cimi.</s> </p> <p type="head"> <s id="s.000515">THEOREMA XVI. PROPOSITIO XX.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000516">Pri&longs;mata omnia & pyramides, quæ in ei&longs;dem, <lb/> uel æqualibus ba&longs;ibus con&longs;tituuntur, eam inter <lb/> &longs;e proportionem habent, quam altitudines: & &longs;i <lb/> axes cum ba&longs;ibus faciant angulos æquales, eam <lb/> etiam, quam axes habent proportionem.</s> </p> <pb pagenum="25" xlink:href="023/01/057.jpg"/> <p type="main"> <s id="s.000517">Sint duo pri&longs;mata ae, af, quorum eadem ba&longs;is quadri­<lb/> latera abcd: <expan abbr="&longs;itq;">&longs;itque</expan> pri&longs;matis ae altitudo eg; & pri&longs;matis <lb/> af altitudo fh. </s> <s id="s.000518">Dico pri&longs;ma ae ad pri&longs;ma af eam habere <lb/> proportionem, quam eg ad fh. </s> <s id="s.000519">iungatur enim ac: & in <lb/> unoquoque pri&longs;mate duo pri&longs;mata intelligantur, quorum <lb/> <figure id="id.023.01.057.1.jpg" xlink:href="023/01/057/1.jpg"/><lb/> ba&longs;es &longs;int triangu<lb/> la abc, acd. </s> <s id="s.000520">habe <lb/> bunt duo pri&longs;ma­<lb/> te in eadem ba&longs;i <lb/> abc con&longs;tituta, <lb/> proportionem <expan abbr="eã">eam</expan> <lb/> dem, quam ip&longs;o­<lb/> rum altitudines e <lb/> g, fh, ex iam de­<lb/> mon&longs;tratis. </s> <s id="s.000521">& &longs;i­<lb/> militer alia duo, <lb/> quæ &longs;unt in ba&longs;i a <lb/> <arrow.to.target n="marg62"/><lb/> c d. <!-- KEEP S--></s> <s id="s.000522">quare totum pri&longs;ma ae ad pri&longs;ma af eandem propor<lb/> tionem habebit, quam altitudo eg ad fh altitudinem. </s> <lb/> <s id="s.000523">Quòd cum pri&longs;mata &longs;int pyramidum tripla, & ip&longs;æ pyrami<lb/> des, quarum eadem e&longs;t ba&longs;is quadrilatera, & altitudo pri&longs;­<lb/> matum altitudini æqualis, eam inter &longs;e proportionem ha­<lb/> bebunt, quam altitudines.</s> </p> <p type="margin"> <s id="s.000524"><margin.target id="marg62"/>12. quinti</s> </p> <p type="main"> <s id="s.000525">Si uero pri&longs;mata ba&longs;es æquales habeant, <expan abbr="nõ">non</expan> ea&longs;dem, &longs;int <lb/>duo eiu&longs;modi pri&longs;mata ae, fl: & &longs;it ba&longs;is pri&longs;matis ae qua<lb/> drilaterum abcd; & pri&longs;matis fl quadrilaterum fghk. </s> <lb/> <s id="s.000526">Dico pri&longs;ma ae ad pri&longs;ma fl ita e&longs;&longs;e, ut altitudo illius ad <lb/> huius altitudinem. </s> <s id="s.000527">nam &longs;i altitudo &longs;it eadem, <expan abbr="intelligãtur">intelligantur</expan> <lb/> <arrow.to.target n="marg63"/><lb/> duæ pyramides abcde, fghkl. <!-- KEEP S--></s> <s id="s.000528">quæ <expan abbr="ĩtcr&longs;e">inter&longs;e</expan> æquales <expan abbr="erũt">erunt</expan>, <lb/> cum æquales ba&longs;es, & altitudinem eandem habeant. </s> <s id="s.000529">quare <lb/> <arrow.to.target n="marg64"/><lb/> & pri&longs;mata ae, fl, quæ &longs;unt <expan abbr="harũ">harum</expan> pyramidum tripla, æqua­<lb/> lia &longs;int nece&longs;&longs;e e&longs;t. </s> <s id="s.000530">ex quibus per&longs;picue con&longs;tat <expan abbr="propo&longs;itũ">propo&longs;itum</expan>. </s> <lb/> <s id="s.000531">Si uero altitudo pri&longs;matis fl &longs;it maior, à pri&longs;mate fl ab­<lb/> &longs;cindatur pri&longs;ma fm, quod æque altum &longs;it, <expan abbr="atq;">atque</expan> ip&longs;um ae. <pb xlink:href="023/01/058.jpg"/><figure id="id.023.01.058.1.jpg" xlink:href="023/01/058/1.jpg"/><lb/> erunt eædem ra­<lb/> tione pri&longs;mata a <lb/> e, fm inter &longs;e æ­<lb/> qualia. </s> <s id="s.000532">quare &longs;i­<lb/> militer demon­<lb/> &longs;trabitur pri&longs;ma <lb/> fm ad pri&longs;ma fl <lb/> eandem habere <lb/> proportionem, <lb/> quam pri&longs;matis <lb/> fm altitudo ad <lb/> altitudinem ip­<lb/> &longs;ius fl. <!-- KEEP S--></s> <s id="s.000533">ergo & pri&longs;ma ae ad pri&longs;ma fl eandem propor­<lb/> tionem habebit, quam altitudo ad altitudinem. </s> <s id="s.000534">&longs;equitur <lb/> igitur ut & pyramides, quæ in æqualibus ba&longs;ibus <expan abbr="con&longs;tituũ">con&longs;tituun</expan><lb/> tur, eandem inter &longs;e &longs;e, quam altitudines, proportionem <lb/> habeant.</s> </p> <p type="margin"> <s id="s.000535"><margin.target id="marg63"/>6. duode<lb/> cimi</s> </p> <p type="margin"> <s id="s.000536"><margin.target id="marg64"/>25. quinti</s> </p> <figure id="id.023.01.058.2.jpg" xlink:href="023/01/058/2.jpg"/> <p type="main"> <s id="s.000537">Sint deinde pri&longs;mata ae, af in eadem ba&longs;i abcd; <expan abbr="quorũ">quorum</expan> <lb/> axes cum ba&longs;ibus æquales angulos contineant: & &longs;it pri&longs;­ <pb pagenum="26" xlink:href="023/01/059.jpg"/>matis ae axis gh; & pri&longs;matis af axis lh. </s> <s id="s.000538">Dico pri&longs;ma <lb/> ae ad pri&longs;ma af eam proportionem habere, quam gh ad <lb/> h l. <!-- REMOVE S-->ducantur à punctis gl perpendiculares ad ba&longs;is pla­<lb/> <figure id="id.023.01.059.1.jpg" xlink:href="023/01/059/1.jpg"/><lb/> num gK, lm: & iungantur kh, <lb/> h m. </s> <s id="s.000539">Itaque quoniam anguli gh <lb/> k, lhm &longs;unt æquales, &longs;imiliter ut <lb/> &longs;upra demon&longs;trabimus, triangu­<lb/> la ghK, lhm &longs;imilia e&longs;&longs;e; & ut g <lb/> K ad lm, ita gh ad hl. </s> <s id="s.000540">habet au<lb/> tem pri&longs;ma ae ad pri&longs;ma af ean <lb/> dem proportionem, quam altitu<lb/> do gK ad altitudinem lm, &longs;icuti <lb/> demon&longs;tratum e&longs;t. </s> <s id="s.000541">ergo & ean­<lb/> dem habebit, quam gh, ad hl. <!-- REMOVE S-->py<lb/> ramis igitur abcdg ad pyrami­<lb/> dem abcdl eandem proportio­<lb/> nem habebit, quam axis gh ad hl axem.</s> </p> <figure id="id.023.01.059.2.jpg" xlink:href="023/01/059/2.jpg"/> <p type="main"> <s id="s.000542">Denique &longs;int pri&longs;mata ae, ko in æqualibus ba&longs;ibus ab <lb/> cd, klmn con&longs;tituta; quorum axes cum ba&longs;ibus æquales <lb/> faciant angulos: <expan abbr="&longs;itq;">&longs;itque</expan> pri&longs;matis ae axis fg, & altitudo fh: <lb/> pri&longs;matis autem ko axis pq, & altitudo pr. </s> <s id="s.000543">Dico pri&longs;ma <lb/> ae ad pri&longs;ma ko ita e&longs;&longs;e, ut fg ad pq. </s> <s id="s.000544">iunctis enim gh, <pb xlink:href="023/01/060.jpg"/>qr, eodem, quo &longs;upra, modo o&longs;tendemus<!--ostendemns (orig.)--> fg ad pq, ut fh <lb/> ad pr. </s> <s id="s.000545">&longs;ed pri&longs;ma ae ad ip&longs;um ko e&longs;t, ut fh ad pr. </s> <s id="s.000546">ergo <lb/> & ut fg axis ad axem pq.</s> <s id="s.000547"> ex quibus &longs;it, ut pyramis abcdf <lb/> <figure id="id.023.01.060.1.jpg" xlink:href="023/01/060/1.jpg"/><lb/> ad <expan abbr="pyrami-d&etilde;">pyrami­<lb/> dem</expan> klmnp <lb/> eandem ha<lb/> beat pro ­<lb/> portion&etilde;, <lb/> <expan abbr="quã">quam</expan> axis ad <lb/> <expan abbr="ax&etilde;">axem</expan>. </s> <s id="s.000548">quod <lb/> <expan abbr="demon&longs;trã">demon&longs;tran</expan> <lb/> <expan abbr="dũ">dum</expan> &longs;uerat.</s> </p> <p type="main"> <s id="s.000549">Simili ra<lb/> tione in a­<lb/> liis pri&longs;ma­<lb/> tibus & py<lb/> ramidibus eadem demon&longs;trabuntur.</s> </p> <p type="head"> <s id="s.000550">THEOREMA XVII. PROPOSITIO XXI.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000551">Pri&longs;mata omnia, & pyramides inter &longs;e propor<lb/> tionem habent compo&longs;itam ex proportione ba­<lb/> &longs;ium, & proportione altitudinum.</s> </p> <p type="main"> <s id="s.000552">Sint duo pri&longs;mata ae, gm: <expan abbr="&longs;itq;">&longs;itque</expan> pri&longs;matis ae ba&longs;is qua<lb/> drilaterum abcd, & altitudo ef: pri&longs;matis uero gm ba­<lb/> &longs;is quadrilaterum ghKl, & altitudo mn. </s> <s id="s.000553">Dico pri&longs;ma ae <lb/> ad pri&longs;ma gm proportionem habere compo&longs;itam ex pro<lb/> portione ba&longs;is abcd ad ba&longs;im ghkl, & ex proportione <lb/> altitudinis ef, ad altitudinem mn.</s> </p> <p type="main"> <s id="s.000554">Sint enim primum ef, mn æquales: & ut ba&longs;is abcd <lb/> ad ba&longs;im ghkl, ita fiat linea, in qua o ad lineam, in qua p: <lb/> ut autem ef ad mn, ita linea p ad lineam q.</s> <s id="s.000555"> erunt lineæ <lb/> pq inter &longs;e æquales. </s> <s id="s.000556">Itaque pri&longs;ma ae ad pri&longs;ma gm <expan abbr="eã">eam</expan> <pb pagenum="27" xlink:href="023/01/061.jpg"/>proportionem habet, quam ba&longs;is abcd ad ba&longs;im ghkl: <lb/> &longs;i enim intelligantur duæ pyramides abcde, ghklm, ha­<lb/> bebunt hæ inter &longs;e proportionem eandem, quam ip&longs;arum <lb/> ba&longs;es ex &longs;exta duodecimi elementorum. </s> <s id="s.000557">Sed ut ba&longs;is abcd <lb/> ad ghKl ba&longs;im, ita linea o ad lineam p; hoc e&longs;t ad lineam q <lb/> ei æqualem. </s> <s id="s.000558">ergo pri&longs;ma ae ad pri&longs;ma gm e&longs;t, ut linea o <lb/> ad lineam q.</s> <s id="s.000559"> proportio autem o ad q copo&longs;ita e&longs;t ex pro­<lb/> portione o ad p, & ex proportione p ad q.</s> <s id="s.000560"> quare pri&longs;ma <lb/> ae ad pri&longs;ma gm, & idcirco pyramis abcde, ad pyrami­<lb/> dem ghKlm proportionem habet ex ei&longs;dem proportio­<lb/> nibus compo&longs;itam, uidelicet ex proportione ba&longs;is abcd <lb/> ad ba&longs;im ghKl, & ex proportione altitudinis ef ad mn al<lb/> titudinem. </s> <s id="s.000561">Quòd &longs;i lineæ ef, mn inæquales ponantur, &longs;it <lb/> ef minor: & ut ef ad mn, ita fiat linea p ad lineam u: de <lb/> <figure id="id.023.01.061.1.jpg" xlink:href="023/01/061/1.jpg"/><lb/> inde ab ip&longs;a mn ab&longs;cindatur rn æqualis ef: & per r duca­<lb/> tur planum, quod oppo&longs;itis planis æquidi&longs;tans faciat &longs;e­<lb/> ctionem st. </s> <s id="s.000562">erit pri&longs;ma ae, ad pri&longs;ma gt, ut ba&longs;is abcd <lb/> ad ba&longs;im ghkl; hoc e&longs;t ut o ad p: ut autem pri&longs;ma gt ad <lb/> <arrow.to.target n="marg65"/><lb/> pri&longs;ma gm, ita altitudo rn; hoc e&longs;t ef ad altitudine mn; <lb/> uidelicet linea p ad lineam u. </s> <s id="s.000563">ergo ex æquali pri&longs;ma ae ad <lb/> pri&longs;ma gm e&longs;t, ut linea o ad ip&longs;am u. </s> <s id="s.000564">Sed proportio o ad <lb/> u <expan abbr="cõpo&longs;ita">compo&longs;ita</expan> e&longs;t ex proportione o ad p, quæ e&longs;t ba&longs;is abcd <lb/> ad ba&longs;im ghkl; & ex proportione p ad u, quæ e&longs;t altitudi­<lb/> nis ef ad altitudinem mn. </s> <s id="s.000565">pri&longs;ma igitur ae ad pri&longs;ma gm <pb xlink:href="023/01/062.jpg"/>compo&longs;itam proportionem habet ex proportione <expan abbr="ba&longs;iũ">ba&longs;ium</expan>, <lb/> & proportione altitudinum. </s> <s id="s.000566">Quare & pyramis, cuius ba­<lb/> &longs;is e&longs;t quadrilaterum abcd, & altitudo ef ad pyramidem, <lb/> <figure id="id.023.01.062.1.jpg" xlink:href="023/01/062/1.jpg"/><lb/> cuius ba&longs;is quadrilaterum ghKl, & altitudo mn, compo&longs;i<lb/> tam habet proportionem ex proportione ba&longs;ium abcd, <lb/> ghkl, & ex proportione altitudinum ef, mn. </s> <s id="s.000567">quod qui­<lb/> dem demon&longs;tra&longs;&longs;e oportebat.</s> </p> <p type="margin"> <s id="s.000568"><margin.target id="marg65"/>20. huius</s> </p> <p type="main"> <s id="s.000569">Ex iam demon&longs;tratis per&longs;picuum e&longs;t, pri&longs;ma <lb/> ta omnia, & pyramides, in quibus axes cum ba&longs;i­<lb/> bus æquales angulos continent, proportionem <lb/> habere compo&longs;itam ex ba&longs;ium proportione, & <lb/> proportione axium. </s> <s id="s.000570">demon&longs;tratum e&longs;t enim, a­<lb/> xes inter &longs;e eandem proportionem habere, quam <lb/> ip&longs;æ altitudines.</s> </p> <p type="head"> <s id="s.000571">THEOREMA XVIII. PROPOSITIO XXII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000572">CVIVSLIBEt pyramidis, & cuiuslibet coni, <pb pagenum="28" xlink:href="023/01/063.jpg"/>uel coni portionis axis à centro grauitatis ita diui <lb/> ditur, ut pars, quæ terminatur ad uerticem reli­<lb/> quæ partis, quæ ad ba&longs;im, &longs;it tripla.</s> </p> <p type="main"> <s id="s.000573">Sit pyramis, cuius ba&longs;is triangulum abc; axis de; & gra<lb/> uitatis centrum K. <!-- KEEP S--></s> <s id="s.000574">Dico lineam dk ip&longs;ius Ke triplam e&longs;&longs;e. </s> <lb/> <s id="s.000575">trianguli enim bdc centrum grauitatis &longs;it punctum f; <expan abbr="triã">trian</expan><lb/> guli adc <expan abbr="centrũ">centrum</expan> g; & trianguli adb &longs;it h: & iungantur af, <lb/> b g, ch. </s> <s id="s.000576">Quoniam igitur <expan abbr="centrũ">centrum</expan> grauitatis pyramidis in axe <lb/> <arrow.to.target n="marg66"/><lb/> <expan abbr="cõ&longs;i&longs;tit">con&longs;i&longs;tit</expan>: <expan abbr="&longs;untq;">&longs;untque</expan> de, af, bg, ch <expan abbr="eiu&longs;d&etilde;">eiu&longs;dem</expan> pyramidis axes: conue<lb/> nient omnes in <expan abbr="id&etilde;">idem</expan> <expan abbr="punctũ">punctum</expan> k, quod e&longs;t grauitatis centrum. </s> <lb/> <s id="s.000577">Itaque animo concipiamus hanc pyramidem diui&longs;am in <lb/> quatuor pyramides, quarum ba&longs;es &longs;int ip&longs;a pyramidis <lb/> <arrow.to.target n="marg67"/><lb/> <figure id="id.023.01.063.1.jpg" xlink:href="023/01/063/1.jpg"/><lb/> triangula; & <emph type="ul"/>axis<emph.end type="ul"/> pun­<lb/> ctum k quæ quidem py­<lb/> ramides inter &longs;e æquales <lb/> &longs;unt, ut <expan abbr="demõ&longs;trabitur">demon&longs;trabitur</expan>. </s> <lb/> <s id="s.000578">Ducatur <expan abbr="enĩ">enim</expan> per lineas <lb/> dc, de planum <expan abbr="&longs;ecãs">&longs;ecans</expan>, ut <lb/> &longs;it ip&longs;ius, & ba&longs;is abc <expan abbr="cõ">com</expan><lb/> munis &longs;ectio recta linea <lb/> cel: <expan abbr="eiu&longs;d&etilde;">eiu&longs;dem</expan> uero & <expan abbr="triã-guli">trian­<lb/> guli</expan> adb &longs;it linea dhl. <!-- REMOVE S-->erit linea al æqualis ip&longs;i <lb/> lb: nam centrum graui­<lb/> tatis trianguli con&longs;i&longs;tit <lb/> in linea, quæ ab angulo <lb/> ad dimidiam ba&longs;im per­<lb/> ducitur, ex tertia deci­<lb/> ma Archimedis. <!-- KEEP S--></s> <lb/> <s id="s.000579">quare <lb/> <arrow.to.target n="marg68"/><lb/> triangulum acl æquale <lb/> e&longs;t triangulo bcl: & propterea pyramis, cuius ba&longs;is trian­<lb/> gulum acl, uertex d, e&longs;t æqualis pyramidi, cuius ba&longs;is bcl <lb/> <arrow.to.target n="marg69"/><lb/> triangulum, & idem uertex. </s> <s id="s.000580">pyramides enim, quæ ab <expan abbr="eod&etilde;">eodem</expan> <pb xlink:href="023/01/064.jpg"/>&longs;unt uertice, eandem proportionem habent, quam <expan abbr="ip&longs;arũ">ip&longs;arum</expan> <lb/> ba&longs;es. </s> <s id="s.000581">eadem ratione pyramis aclk pyramidi bclk & py<lb/> ramis adlk ip&longs;i bdlk pyramidi æqualis erit. </s> <s id="s.000582">Itaque &longs;i a py<lb/>ramide acld auferantur pyramides aclk, adlk: & à pyra<lb/> mide bcld <expan abbr="auferãtur">auferantur</expan> pyramides bclk dblK: quæ relin­<lb/> quuntur erunt æqualia. </s> <s id="s.000583">æqualis igitur e&longs;t pyramis acdk <lb/> pyramidi bcdK. <!-- KEEP S--></s> <s id="s.000584">Rur&longs;us &longs;i per lineas ad, de ducatur pla­<lb/> num quod pyramidem &longs;ccet: <expan abbr="&longs;itq;">&longs;itque</expan> eius & ba&longs;is communis <lb/> &longs;ectio aem: &longs;imiliter o&longs;tendetur pyramis abdK æqualis <lb/> pyramidi acdk. </s> <s id="s.000585">ducto denique alio plano per lineas ca, <lb/> af: ut eius, & trianguli cdb communis &longs;ectio &longs;it cfn, py­<lb/> ramis abck pyramidi acdk æqualis demon&longs;trabitur. </s> <s id="s.000586"><expan abbr="cũ">cum</expan> <lb/> ergo tres pyramides bcdk, abdk, abck uni, & eidem py<lb/> ramidi acdk &longs;int æquales, omnes inter &longs;e &longs;e æquales <expan abbr="erũt">erunt</expan>. </s> <lb/> <s id="s.000587">Sed ut pyramis abcd ad pyramidem abck ita de axis ad <lb/> axem ke, ex uige&longs;ima propo&longs;itione huius: &longs;unt enim hæ <lb/> pyramides in eadem ba&longs;i, & axes cum ba&longs;ibus æquales con<lb/> tinent angulos, quòd in eadem recta linea con&longs;tituantur. </s> <lb/> <s id="s.000588">quare diuidendo, ut tres pyramides acdk, bcdK, abdK <lb/> ad pyramidem abcK, ita dk ad Ke. </s> <s id="s.000589">con&longs;tat igitur lineam <lb/> dK ip&longs;ius Ke triplam e&longs;&longs;e. </s> <s id="s.000590">&longs;ed & ak tripla e&longs;t Kf: itemque <lb/> bK ip&longs;ius kg: & ck ip&longs;ius kl tripla. </s> <s id="s.000591">quod eodem modo <lb/> demon&longs;trabimus.</s> </p> <p type="margin"> <s id="s.000592"><margin.target id="marg66"/>17 huius</s> </p> <p type="margin"> <s id="s.000593"><margin.target id="marg67"/><emph type="italics"/>ucrfex<emph.end type="italics"/></s> </p> <p type="margin"> <s id="s.000594"><margin.target id="marg68"/>1. sexti.</s> </p> <p type="margin"> <s id="s.000595"><margin.target id="marg69"/>5. duode­<lb/> cimi.</s> </p> <p type="main"> <s id="s.000596">Sit pyramis, cuius ba&longs;is quadrilaterum abcd; axis ef: <lb/> & diuidatur ef in g, ita ut eg ip&longs;ius gf &longs;it tripla. </s> <s id="s.000597">Dico cen­<lb/> trum grauitatis pyramidis e&longs;&longs;e punctum g. <!-- REMOVE S-->ducatur enim <lb/> linea bd diuidens ba&longs;im in duo triangula abd, bcd: ex <lb/> quibus <expan abbr="intelligãtur">intelligantur</expan> <expan abbr="cõ&longs;titui">con&longs;titui</expan> duæ pyramides abde, bcde: <lb/> &longs;itque pyramidis abde axis eh; & pyramidis bcde axis <lb/> eK: & iungatur hK, quæ per f tran&longs;ibit: e&longs;t enim in ip&longs;a hK <lb/> centrum grauitatis magnitudinis compo&longs;itæ ex triangulis <lb/> abd, bcd, hoc e&longs;t ip&longs;ius quadrilateri. </s> <s id="s.000598">Itaque centrum gra<lb/> uitatis pyramidis abde &longs;it punctum l: & pyramidis bcde <lb/> <arrow.to.target n="marg70"/><lb/> &longs;it m. </s> <s id="s.000599">ducta igitur lm ip&longs;i hm lineæ æquidi&longs;tabit. </s> <s id="s.000600">nam el ad <pb pagenum="29" xlink:href="023/01/065.jpg"/>lh eandem habet proportionem, quam em ad mk, uideli­<lb/> cet triplam. </s> <s id="s.000601">quare linea lm ip&longs;am ef &longs;ecabit in puncto g: <lb/> etenim eg ad gf e&longs;t, ut el ad lh. </s> <s id="s.000602">præterea quoniam hk, lm <lb/> æquidi&longs;tant, erunt triangula hef, leg &longs;imilia: <expan abbr="itemq;">itemque</expan> inter <lb/> &longs;e &longs;imilia fek gem: & ut ef ad eg, ita hf ad lg: & ita fK ad <lb/> gm. </s> <s id="s.000603">ergo ut hf ad lg, ita fk ad gm: & permutando ut hf <lb/> ad fK, ita lg ad gm. </s> <s id="s.000604">&longs;ed cum h &longs;it centrum trianguli abd; <lb/> & k <expan abbr="triãguli">trianguli</expan> bcd <expan abbr="punctũ">punctum</expan> uero f totius quadrilateri abcd <lb/> centrum: erit ex 8. Archimedis de centro grauitatis plano<lb/> rum hf ad fk ut triangulum bcd ad triangulum abd: ut, <lb/> autem bcd triangulum ad triangulum abd, ita pyramis <lb/> <figure id="id.023.01.065.1.jpg" xlink:href="023/01/065/1.jpg"/><lb/> bcde ad pyramidem abde. </s> <s id="s.000605">ergo <lb/> linea lg ad gm erit, ut pyramis <lb/> bcde ad <expan abbr="pyramid&etilde;">pyramidem</expan> abde. </s> <s id="s.000606">ex quo <lb/> &longs;equitur, ut totius pyramidis <lb/> abcde punctum g &longs;it grauitatis <lb/> centrum. </s> <s id="s.000607">Rur&longs;us &longs;it pyramis ba­<lb/> &longs;im habens pentagonum abcde: <lb/> & axem fg: <expan abbr="diuidaturq;">diuidaturque</expan> axis in <expan abbr="pũ">pun</expan><lb/> cto h, ita ut fh ad hg triplam habe<lb/> at proportionem. </s> <s id="s.000608">Dico h grauita­<lb/> tis <expan abbr="centrũ">centrum</expan> e&longs;&longs;e pyramidis abcdef. </s> <lb/> <s id="s.000609">iungatur enim eb: <expan abbr="intelligaturq;">intelligaturque</expan> <lb/> pyramis, cuius uertex f, & ba&longs;is <lb/> triangulum abe: & alia pyramis <lb/> intelligatur eundem uerticem ha­<lb/> bens, & ba&longs;im bcde <expan abbr="quadrilaterũ">quadrilaterum</expan>: <lb/> &longs;it autem pyramidis abef axis fk<lb/> & grauitatis centrum l: & pyrami<lb/> dis bcdef axis fm, & centrum gra <lb/> uitatis n:<expan abbr="iunganturq;">iunganturque</expan> km, ln; <lb/> quæ per puncta gh tran&longs;ibunt. </s> <lb/> <s id="s.000610">Rur&longs;us eodem modo, quo &longs;up ra, <lb/> demon&longs;trabimus lineas Kgm, lhn &longs;ibi ip&longs;is æquidi&longs;tare: <pb xlink:href="023/01/066.jpg"/>& denique punctum h pyramidis abcdef grauitatis e&longs;&longs;e <lb/> centrum, & ita in aliis.</s> </p> <p type="margin"> <s id="s.000611"><margin.target id="marg70"/>2. fexti.</s> </p> <p type="main"> <s id="s.000612">Sit conus, uel coni portio axem habens bd: &longs;eceturque <lb/> plano per axem, quod &longs;ectionem faciat triangulum abc: <lb/> & bd axis diuidatur in c, ita ut be ip&longs;ius ed &longs;it tripla. </s> <lb/> <s id="s.000613">Dico punctum e coni, uel coni portionis, grauitatis <lb/> e&longs;&longs;e centrum. </s> <s id="s.000614">Si enim fieri pote&longs;t, &longs;it centrum f: & pro­<lb/> ducatur ef extra figuram in g. <!-- KEEP S--></s> <s id="s.000615">quam uero proportionem <lb/> habet ge ad ef, habeat ba&longs;is coni, uelconi portionis, hoc <lb/> e&longs;t circulus, uel ellip&longs;is circa diametrum ac ad aliud &longs;pa­<lb/> cium, in quo h. </s> <s id="s.000616">Itaque in circulo, uel ellip&longs;i plane de&longs;cri­<lb/> batur rectilinea figura axlmcnop, ita ut quæ <expan abbr="relinquũ-tur">relinquun­<lb/> tur</expan> portiones &longs;int minores &longs;pacio h: & intelligatur pyra­<lb/> mis ba&longs;im habens rectilineam figuram aKlmcnop, & <lb/> axem bd; cuius quidem grauitatis centrum erit punctum <lb/> e, ut iam demon&longs;trauimus. </s> <s id="s.000617">Et quoniam portiones &longs;unt <lb/> minores &longs;pacio h, circulus, uel ellip&longs;is ad portiones ma­<lb/> <figure id="id.023.01.066.1.jpg" xlink:href="023/01/066/1.jpg"/><lb/> iorem proportionem habet, quam ge ad ef. </s> <s id="s.000618">&longs;ed ut circu­<lb/> lus, uel ellip&longs;is ad figuram rectilineam &longs;ibi in&longs;criptam, ita <lb/> conus, uel coni portio ad pyramidem, quæ figuram rectili­<lb/> neam pro ba&longs;i habet; & altitudinem æqualem: etenim &longs;u­ <pb pagenum="30" xlink:href="023/01/067.jpg"/><arrow.to.target n="marg71"/><lb/> pra demon&longs;tratum e&longs;t, ita e&longs;&longs;e cylindrum, uel cylindri por­<lb/> tionem ad pri&longs;ma, cuius ba&longs;is rectilinea figura, & æqua­<lb/> lis altitudo. </s> <s id="s.000619">ergo per conuer&longs;ionem rationis, ut circulus, <lb/> uel ellip&longs;is ad portiones, ita conus, uel coni portio ad por­<lb/> tiones &longs;olidas. </s> <s id="s.000620">quare conus uel coni portio ad portiones <lb/> &longs;olidas maiorem habet proportionem, quam ge ad ef: & <lb/> diuidendo, pyramis ad portiones &longs;olidas maiorem pro­<lb/> portionem habet, quam gf ad fe. </s> <s id="s.000621">fiat igitur qf ad fe <lb/> ut pyramis ad dictas portiones. </s> <s id="s.000622">Itaque quoniam a cono <lb/> uel coni portione, cuius grauitatis centrum e&longs;t f, aufer­<lb/> tur pyramis, cuius centrum e; reliquæ magnitudinis, <lb/> quæ ex &longs;olidis portionibus con&longs;tat, centrum grauitatis <lb/> erit in linea ef protracta, & in puncto q.</s> <s id="s.000623"> quod fieri <lb/> non pote&longs;t: e&longs;t enim centrum grauitatis intra. </s> <s id="s.000624">Con&longs;tat <lb/> igitur coni, uel coni portionis grauitatis centrum e&longs;&longs;e pun<lb/> ctum e. </s> <s id="s.000625">quæ omnia demon&longs;trare oportebat.</s> </p> <p type="margin"> <s id="s.000626"><margin.target id="marg71"/>8 huius</s> </p> <p type="head"> <s id="s.000627">THEOREMA XIX. PROPOSITIO XXIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000628">QVODLIBET fru&longs;tum à pyramide, quæ <lb/> triangularem ba&longs;im habeat, ab&longs;ci&longs;&longs;um, diuiditur <lb/> in tres pyramides proportionales, in ea proportio <lb/> ne, quæ e&longs;t lateris maioris ba&longs;is ad latus minoris <lb/> ip&longs;i re&longs;pondens.</s> </p> <p type="main"> <s id="s.000629">Hoc demon&longs;trauit Leonardus Pi&longs;anus in libro, qui de­<lb/> praxi geometriæ in&longs;cribitur. </s> <s id="s.000630">Sed quoniam is adhuc im­<lb/> pre&longs;&longs;us non e&longs;t, nos ip&longs;ius demon&longs;trationem breuiter <lb/> per&longs;tringemus, rem ip&longs;am &longs;ecuti, non uerba. </s> <s id="s.000631">Sit fru­<lb/> &longs;tum pyramidis abcdef, cuius maior ba&longs;is triangulum <lb/> abc, minor def: & iunctis ae, cc, cd, per, line­<lb/> as ae, ec ducatur planum &longs;ecans fru&longs;tum: itemque per <lb/> lineas ec, cd; & per cd, da alia plana ducantur, quæ <lb/> diuident fru&longs;tum in trcs pyramides abce, adce, defc. <pb xlink:href="023/01/068.jpg"/>Dico eas proportionales e&longs;&longs;e in proportione, quæ e&longs;t la­<lb/> teris ab adlatus de, ita ut earum maior &longs;it abce, me­<lb/> dia adce, & minor defc. <!-- KEEP S--></s> <s id="s.000632">Quoniam enim lineæ de, <lb/> ab æquidi&longs;tant; & inter ip&longs;as &longs;unt triangula abe, ade; <lb/> <arrow.to.target n="marg72"/><lb/> <figure id="id.023.01.068.1.jpg" xlink:href="023/01/068/1.jpg"/><lb/> erit triangulum abe <lb/> ad triangulum abe, <lb/> ut linea ab ad lineam <lb/> de. </s> <s id="s.000633">ut autem triangu<lb/> lum abe ad triangu­<lb/> <arrow.to.target n="marg73"/><lb/> lum abe, ita pyramis <lb/> abec ad pyramidem <lb/> adec: habent enim <lb/> altitudinem eandem, <lb/> quæ e&longs;tà puncto cad <lb/> planum, in quo qua­<lb/> <arrow.to.target n="marg74"/><lb/> drilaterum abed. <!-- KEEP S--></s> <s id="s.000634">er­<lb/> go ut ab ad de, ita pyramis abec ad pyramidem adec. <!-- KEEP S--></s> <lb/> <s id="s.000635">Rur&longs;us quoniam æquidi&longs;tantes &longs;unt ac, df; erit eadem <lb/> <arrow.to.target n="marg75"/><lb/> ratione pyramis adce ad pyramidem cdfe, ut ac ad <lb/> df. </s> <s id="s.000636">Sed ut ac ad df, ita ab ad de, quoniam triangula <lb/> abc, def &longs;imilia &longs;unt, ex nona huius. </s> <s id="s.000637">quare ut pyramis <lb/> abce ad pyramidem abce, ita pyramis adce ad ip&longs;am<lb/> defc. <!-- REMOVE S-->fru&longs;tum igitur abcdef diuiditur in tres pyramides <lb/> proportionales in ea proportione, quæ e&longs;t lateris ab ad de <lb/> latus, & earum maior e&longs;t cabe, media adce, & minor <lb/> defc. <!-- REMOVE S-->quod demon&longs;trare oportebat.</s> </p> <p type="margin"> <s id="s.000638"><margin.target id="marg72"/>1. &longs;exti.</s> </p> <p type="margin"> <s id="s.000639"><margin.target id="marg73"/>5. duodeci <lb/> mi.</s> </p> <p type="margin"> <s id="s.000640"><margin.target id="marg74"/>11. quinti.</s> </p> <p type="margin"> <s id="s.000641"><margin.target id="marg75"/>4 &longs;exti.</s> </p> <p type="head"> <s id="s.000642">PROBLEMA V. PROPOSITIO XXIIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000643">QVODLIBET fru&longs;tum pyramidis, uel coni, <lb/> uel coni portionis, plano ba&longs;i æquidi&longs;tanti ita &longs;e­<lb/> care, ut &longs;ectio &longs;it proportionalis inter maiorem, <lb/> & minorem ba&longs;im.</s> </p> <pb pagenum="31" xlink:href="023/01/069.jpg"/> <p type="main"> <s id="s.000644">SIT fru&longs;tum pyramidis ae, cuius maior ba&longs;is triangu­<lb/> lum abc, minor def: & oporteat ip&longs;um plano, quod ba&longs;i <lb/> æquidi&longs;tet, ita &longs;ecare, ut &longs;ectio &longs;it proportionalis inter <expan abbr="triã">trian</expan> <lb/> gula abc, def. </s> <s id="s.000645">Inueniatur inter lineas ab, de media pro­<lb/> portionalis, quæ &longs;it bg: & à puncto g erigatur gh æquidi­<lb/> &longs;tans be, <expan abbr="&longs;ecansq;">&longs;ecansque</expan> ad in h: deinde per h ducatur planum <lb/> ba&longs;ibus æquidi&longs;tans, cuius &longs;ectio &longs;it triangulum hkl. <!-- KEEP S--></s> <s id="s.000646">Dico <lb/> triangulum hKl proportionale e&longs;&longs;e inter triangula abc, <lb/> <figure id="id.023.01.069.1.jpg" xlink:href="023/01/069/1.jpg"/><lb/> def, hoc e&longs;t triangulum abc ad <lb/> triangulum hKl eandem habere <lb/> proportionem, quam <expan abbr="triãgulum">triangulum</expan> <lb/> hKl ad ip&longs;um def. </s> <s id="s.000647"><expan abbr="Quoniã">Quoniam</expan> enim <lb/> <arrow.to.target n="marg76"/><lb/> lineæ ab, hK æquidi&longs;tantium pla<lb/> norum &longs;ectiones inter &longs;e æquidi­<lb/> &longs;tant: atque æquidi&longs;tant bk, gh: <lb/> <arrow.to.target n="marg77"/><lb/> linea hk ip&longs;i gb e&longs;t æqualis: & pro<lb/> pterea proportionalis inter ab, <lb/> de. </s> <s id="s.000648">quare ut ab ad hK, ita e&longs;t hk<lb/> ad de. </s> <s id="s.000649">fiat ut hk ad de, ita de <lb/> ad aliam lineam, in qua &longs;it m. </s> <s id="s.000650">erit <lb/> ex æquali ut ab ad de, ita hk ad <lb/> <arrow.to.target n="marg78"/><lb/> m. </s> <s id="s.000651">Et quoniam triangula abc, <lb/> hKl, def &longs;imilia &longs;unt; <expan abbr="triangulũ">triangulum</expan> <lb/> <arrow.to.target n="marg79"/><lb/> abc ad triangulum hkl e&longs;t, ut li­<lb/> nea ab ad lineam de: <expan abbr="triangulũ">triangulum</expan> <lb/> <arrow.to.target n="marg80"/><lb/> autem hkl ad ip&longs;um def e&longs;t, ut hk ad m. </s> <s id="s.000652">ergo triangulum <lb/> abc ad triangulum hkl eandem proportionem habet, <lb/> quam triangulum hKl ad ip&longs;um def. </s> <s id="s.000653">Eodem modo in a­<lb/> liis fru&longs;tis pyramidis idem demon&longs;trabitur.</s> </p> <p type="margin"> <s id="s.000654"><margin.target id="marg76"/>16. unde<lb/> cimi</s> </p> <p type="margin"> <s id="s.000655"><margin.target id="marg77"/>34. primi</s> </p> <p type="margin"> <s id="s.000656"><margin.target id="marg78"/>9. huius <lb/> corol.</s> </p> <p type="margin"> <s id="s.000657"><margin.target id="marg79"/>20. &longs;exti</s> </p> <p type="margin"> <s id="s.000658"><margin.target id="marg80"/>11. quinti</s> </p> <p type="main"> <s id="s.000659">Sit fru&longs;tum coni, uel coni portionis ad: & &longs;ecetur plano <lb/> per axem, cuius &longs;ectio &longs;it abcd, ita ut maior ip&longs;ius ba&longs;is &longs;it <lb/> circulus, uel ellip&longs;is circa diametrum ab; minor circa cd. <!-- KEEP S--></s> <lb/> <s id="s.000660">Rur&longs;us inter lineas ab, cd inueniatur proportionalis be: <lb/> & ab e ducta ef æquidi&longs;tante bd, quæ lineam ca in f &longs;ecet, <pb xlink:href="023/01/070.jpg"/>per f planum ba&longs;ibus æquidi&longs;tans ducatur, ut &longs;it &longs;ectio cir<lb/> culus, uel ellip&longs;is circa diametrum fg. <!-- KEEP S--></s> <s id="s.000661">Dico &longs;ectionem ab <lb/> ad &longs;ectionem fg eandem proportionem habere, quam fg <lb/> ad ip&longs;am cd. <!-- KEEP S--></s> <s id="s.000662">Simili enim ratione, qua &longs;upra, demon&longs;trabi­<lb/> tur quadratum ab ad quadratum fg ita e&longs;&longs;e, ut <expan abbr="quadratũ">quadratum</expan> <lb/> <arrow.to.target n="marg81"/><lb/> fg ad cd quadratum. </s> <s id="s.000663">Sed circuli inter &longs;e eandem propor­<lb/> tionem habent, quam diametrorum quadrata. </s> <s id="s.000664">ellip&longs;es au­<lb/> tem circa ab, fg, cd, quæ &longs;imiles &longs;unt, ut o&longs;tendimus in <expan abbr="cõ-mentariis">com­<lb/> mentariis</expan> in principium libri Archimedis de conoidibus, <lb/> & &longs;phæroidibus, eam <expan abbr="hab&etilde;t">habent</expan> proportionem, quam quadra<lb/>ta diametrorum, quæ eiu&longs;dem rationis &longs;unt, ex corollario­ <lb/> <figure id="id.023.01.070.1.jpg" xlink:href="023/01/070/1.jpg"/><lb/> &longs;eptimæ propo&longs;itionis eiu&longs;dem li­<lb/> bri. </s> <s id="s.000665">ellip&longs;es enim nunc appello ip­<lb/> &longs;a &longs;pacia ellip&longs;ibus contenta. </s> <s id="s.000666">ergo <lb/> circulus, uel ellip&longs;is ab ad <expan abbr="circulũ">circulum</expan>, <lb/> uel ellip&longs;im fg eam proportionem <lb/> habet, quam circulus, uel ellip&longs;is <lb/> fg ad circulum uel ellip&longs;im cd. <!-- KEEP S--></s> <lb/> <s id="s.000667">quod quidem faciendum propo­<lb/> &longs;uimus.</s> </p> <p type="margin"> <s id="s.000668"><margin.target id="marg81"/>2. duode<lb/> cimi</s> </p> <p type="head"> <s id="s.000669">THEOREMA XX. PROPOSITIO XXV.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000670">QVODLIBET fru&longs;tum pyramidis, uel coni, <lb/> uel coni portionis ad pyramidem, uel conum, uel <lb/> coni portionem, cuius ba&longs;is eadem e&longs;t, & æqualis <lb/> altitudo, eandem <expan abbr="proportion&etilde;">proportionem</expan> habet, quam utræ <lb/> que ba&longs;es, maior, & minor &longs;imul &longs;umptæ vnà <expan abbr="cũ">cum</expan> <lb/>ea, quæ inter ip&longs;as &longs;it proportionalis, ad ba&longs;im ma<lb/> iorem.</s> </p> <pb pagenum="32" xlink:href="023/01/071.jpg"/> <p type="main"> <s id="s.000671">SIT <expan abbr="fru&longs;tũ">fru&longs;tum</expan> pyramidis, uel coni, uel coni portionis ad, <lb/> cuius maior ba&longs;is ab, minor cd. <!-- KEEP S--></s> <s id="s.000672">& &longs;ecetur altero plano <lb/> ba&longs;i æquidi&longs;tante, ita ut &longs;ectio ef &longs;it proportionalis inter <lb/> ba&longs;es ab, cd. <!-- KEEP S--></s> <s id="s.000673">con&longs;tituatur <expan abbr="aut&etilde;">autem</expan> pyramis, uel conus, uel co­<lb/> ni portio agb, cuius ba&longs;is &longs;it eadem, quæ ba&longs;is maior fru­<lb/> <figure id="id.023.01.071.1.jpg" xlink:href="023/01/071/1.jpg"/><lb/> &longs;ti, & altitudo æqualis. </s> <s id="s.000674">Di­<lb/> co fru&longs;tum ad ad pyrami­<lb/> dem, uel conum, uel coni <lb/> portionem agb eandem <lb/> <expan abbr="proportion&etilde;">proportionem</expan> habere, <expan abbr="quã">quam</expan> <lb/> utræque ba&longs;es, ab, cd unà <lb/> cum ef ad ba&longs;im ab. </s> <s id="s.000675">e&longs;t <lb/> enim fru&longs;tum ad æquale <lb/> pyramidi, uel cono, uel co­<lb/> ni portioni, cuius ba&longs;is ex <lb/> tribus ba&longs;ibus ab, ef, cd <lb/> con&longs;tat; & altitudo ip&longs;ius <lb/> altitudini e&longs;t æqualis: quod mox o&longs;tendemus. </s> <s id="s.000676">Sed pyrami<lb/> <figure id="id.023.01.071.2.jpg" xlink:href="023/01/071/2.jpg"/><lb/> des, coni, uel coni <expan abbr="portiões">portiones</expan>, <lb/> quæ &longs;unt æquali altitudine, <lb/> <expan abbr="eãdem">eandem</expan> inter &longs;e, quam ba&longs;es, <lb/> proportionem habent, &longs;icu­<lb/> ti demon&longs;tratum e&longs;t, partim <lb/> <arrow.to.target n="marg82"/><lb/> ab Euclide in duodecimo li­<lb/> bro elementorum, partim à <lb/> nobis in <expan abbr="cõmentariis">commentariis</expan> in un­<lb/> decimam <expan abbr="propo&longs;ition&etilde;">propo&longs;itionem</expan> Ar­<lb/> chimedis de conoidibus, & <lb/> &longs;phæroidibus. </s> <s id="s.000677">quare pyra­<lb/> mis, uel conus, uel coni por­<lb/> tio, cuius ba&longs;is e&longs;t tribus illis <lb/> ba&longs;ibus æqualis ad agb eam <lb/> habet proportionem, quam <lb/> ba&longs;es ab, ef, cd ad ab ba&longs;im. </s> <s id="s.000678">Fru&longs;tum igitur ad ad agb <pb xlink:href="023/01/072.jpg"/>pyramidem, uel conum, uel coni portionem eandem pro­<lb/> portionem habet, quam ba&longs;es ab, cd unà cum ef ad ba­<lb/> &longs;im ab. </s> <s id="s.000679">quod demon&longs;trare uolebamus.</s> </p> <p type="margin"> <s id="s.000680"><margin.target id="marg82"/>6. 11. duo<lb/> decimi</s> </p> <p type="main"> <s id="s.000681">Fru&longs;tum uero ad æquale e&longs;&longs;e pyramidi, uel co<lb/> no, uel coni portioni, cuius ba&longs;is con&longs;tat ex ba&longs;i­<lb/> bus ab, cd, ef, & altitudo fru&longs;ti altitudini e&longs;t æ­<lb/> qualis, hoc modo o&longs;tendemus.</s> </p> <p type="main"> <s id="s.000682">Sit fru&longs;tum pyramidis abcdef, cuius maior ba&longs;is trian­<lb/> gulum abc; minor def: & &longs;ecetur plano ba&longs;ibus æquidi­<lb/> &longs;tante, quod &longs;ectionem faciat triangulum ghk inter trian­<lb/> gula abc, def proportionale. </s> <s id="s.000683">Iam ex iis, quæ demon&longs;trata <lb/> &longs;unt in 23. huius, patet fru&longs;tum abcdef diuidi in tres pyra<lb/> mides proportionales; & earum maiorem e&longs;&longs;e <expan abbr="pyramid&etilde;">pyramidem</expan> <lb/> abcd <expan abbr="minor&etilde;">minorem</expan> uero defb. </s> <s id="s.000684">ergo pyramis à triangulo ghk <lb/> con&longs;tituta, quæ altitudinem habeat fru&longs;ti altitudini æqua­<lb/> lem, proportionalis e&longs;t inter pyramides abcd, defb: & <lb/> idcirco fru&longs;tum abcdef tribus dictis pyramidibus æqua <lb/> <figure id="id.023.01.072.1.jpg" xlink:href="023/01/072/1.jpg"/><lb/> le erit. </s> <s id="s.000685">Itaque &longs;i intelligatur alia pyra­<lb/> mis æque alta, quæ ba&longs;im habeat ex tri<lb/> bus ba&longs;ibus abc, def, ghk con&longs;tan­<lb/> tem; per&longs;picuum e&longs;t ip&longs;am ei&longs;dem py­<lb/> ramidibus, & propterea ip&longs;i fru&longs;to æ­<lb/> qualem e&longs;&longs;e.</s> </p> <p type="main"> <s id="s.000686">Rur&longs;us &longs;it fru&longs;tum pyramidis ag, cu<lb/> ius maior ba&longs;is quadrilaterum abcd, <lb/> minor efgh: & &longs;ecetur plano ba&longs;i­<lb/> bus æquidi&longs;tante, ita ut fiat &longs;ectio qua­<lb/> drilaterum Klmn, quod &longs;it proportio <lb/> nale inter quadrilatera abcd, efgh. </s> <s id="s.000687">Dico pyramidem, <lb/> cuius ba&longs;is &longs;it æqualis tribus quadrilateris abcd, klmn, <lb/> efgh, & altitudo æqualis altitudini fru&longs;ti, ip&longs;i fru&longs;to ag <lb/> æqualem e&longs;&longs;e. </s> <s id="s.000688">Ducatur enim planum per lineas fb, hd, <pb pagenum="33" xlink:href="023/01/073.jpg"/>quod diuidat fru&longs;tum in duo fru&longs;ta triangulares ba&longs;es ha­<lb/> bentia, uidelicet in fru&longs;tum abdefh, & in <expan abbr="fru&longs;tũ">fru&longs;tum</expan> bcdfgh. </s> <lb/> <s id="s.000689">erit triangulum kln proportionale inter triangula abd, <lb/> efh: & triangulum lmn proportionale inter bcd, fgh. </s> <lb/> <s id="s.000690">&longs;ed pyramis æque alta, cuius ba&longs;is con&longs;tat ex tribus trian­<lb/> <figure id="id.023.01.073.1.jpg" xlink:href="023/01/073/1.jpg"/><lb/> gulis abd, klz, efh, demon&longs;trata <lb/> e&longs;t fru&longs;to abdcfh æqualis. </s> <s id="s.000691">& &longs;i­<lb/> militer pyramis, cuius ba&longs;is con­<lb/> &longs;tat ex triangulis bcd, lmn, fgh <lb/> æqualis fru&longs;to bcdfgh: compo­<lb/> nuntur autem tria quadrilatera a <lb/> bcd, klmn, efgh è &longs;ex triangu­<lb/> lis iam dictis. </s> <s id="s.000692">pyramis igitur ba­<lb/> &longs;im habens æqualem tribus qua­<lb/> drilateris, & altitudinem eandem <lb/> ip&longs;i fru&longs;to ag e&longs;t æqualis. </s> <s id="s.000693">Eodem <lb/> modo illud <expan abbr="demõ&longs;trabitur">demon&longs;trabitur</expan> in aliis <lb/> eiu&longs;modi fru&longs;tis.</s> </p> <p type="main"> <s id="s.000694">Sit fru&longs;tum coni, uel coni portionis ad; cuius maior ba­<lb/> &longs;is circulus, uel ellip&longs;is circa diametrum ab; minor circa <lb/> c d: & &longs;ecetur plano, quod ba&longs;ibus æquidi&longs;tet, <expan abbr="faciatq;">faciatque</expan> &longs;e­<lb/> ctionem circulum, uel ellip&longs;im circa diametrum ef, ita ut <lb/> inter circulos, uel ellip&longs;es ab, cd &longs;it proportionalis. </s> <s id="s.000695">Dico <lb/> conum, uel coni portionem, cuius ba&longs;is e&longs;t æqualis tribus <lb/> circulis, uel tribus ellip&longs;ibus ab, ef, cd; & altitudo eadem, <lb/> quæ fru&longs;ti ad, ip&longs;i fru&longs;to æqualem e&longs;&longs;e. </s> <s id="s.000696">producatur enim <lb/> fru&longs;ti &longs;uperficies quou&longs;que coeat in unum punctum, quod <lb/> &longs;it g: & coni, uel coni portionis agb axis &longs;it gh, occurrens <lb/> planis ab, ef, cd in punctis hkl: circa circulum uero de­<lb/> &longs;cribatur quadratum mnop, & circa ellip&longs;im <expan abbr="rectangulũ">rectangulum</expan> <lb/> mnop, quod ex ip&longs;ius diametris con&longs;tat: <expan abbr="iunctisq;">iunctisque</expan> gm, <lb/> g n, go, gp, ex eodem uertice intelligatur pyramis ba&longs;im <lb/> habens dictum quadratum, uel rectangulum: & plana in <lb/> quibus &longs;unt circuli, uel ellip&longs;es ef, cd u&longs;que ad eius latera <pb xlink:href="023/01/074.jpg"/>producantur. </s> <s id="s.000697">Quoniam igitur pyramis &longs;ecatur planis ba&longs;i <lb/> <arrow.to.target n="marg83"/><lb/> æquidi&longs;tantibus, &longs;ectiones &longs;imiles erunt: atque erunt qua­<lb/> drata, uel rectangula circa circulos, uel ellip&longs;es de&longs;cripta, <lb/> quemadmodum & in ip&longs;a ba&longs;i. </s> <s id="s.000698">Sed cum circuli inter &longs;e <expan abbr="eã">eam</expan> <lb/> <arrow.to.target n="marg84"/><lb/> proportionem habeant, quam diametrorum quadrata: <lb/> <expan abbr="itemq;">itemque</expan> ellip&longs;es eam quam rectangula ex ip&longs;arum diametris <lb/> <arrow.to.target n="marg85"/><lb/> con&longs;tantia: & &longs;it circulus, uel ellip&longs;is circa diametrum ef <lb/> <figure id="id.023.01.074.1.jpg" xlink:href="023/01/074/1.jpg"/><lb/> proportionalis inter circulos, uel ellip&longs;es ab, cd; erit re­<lb/> ctangulum ef etiam inter rectangula ab, cd proportio­<lb/> nale: per rectangulum enim nunc breuitatis cau&longs;a <expan abbr="etiã">etiam</expan> ip­<lb/> &longs;um quadratum intelligemus. </s> <s id="s.000699">quare ex iis, quæ proxime <lb/> dicta &longs;unt, pyramis ba&longs;im habens æqualem dictis rectangu<lb/> lis, & altitudinem eandem, quam fru&longs;tum ad, ip&longs;i fru&longs;to à <lb/> pyramide ab&longs;ci&longs;&longs;o æqualis probabitur. </s> <s id="s.000700">ut autem rectangu<lb/> lum cd ad <expan abbr="rectangulũ">rectangulum</expan> ef, ita circulus, uel ellip&longs;is cd ad ef <lb/> circulum, uel ellip&longs;im: <expan abbr="componendoq;">componendoque</expan> ut rectangula cd, <lb/> e f, ad ef rectangulum, ita circuli, uel ellip&longs;es ed, ef, ad ef: <lb/> & ut rectangulum ef ad rectangulum ab, ita circulus, uel <lb/> ellip&longs;is ef ad ab circulum, uel ellip&longs;im. </s> <s id="s.000701">ergo ex æquali, & <lb/> componendo, ut <expan abbr="rectãgula">rectangula</expan> cd, ef, ab ad ip&longs;um ab, ita cir­ <pb pagenum="34" xlink:href="023/01/075.jpg"/>culi, uel ellip&longs;es cd, ef ab ad circulum, uel ellip&longs;im ab. </s> <s id="s.000702">In­<lb/> telligatur pyramis q ba&longs;im habens æqualem tribus rectan <lb/> gulis ab, ef, cd; & altitudinem <expan abbr="eãdem">eandem</expan>, quam fru&longs;tum ad. <!-- KEEP S--></s> <lb/> <s id="s.000703">intelligatur etiam conus, uel coni portio q, eadem altitudi<lb/> ne, cuius ba&longs;is &longs;it tribus circulis, uel tribus ellip&longs;ibus ab, <lb/> ef, cd æqualis. </s> <s id="s.000704">po&longs;tremo intelligatur pyramis alb, cuius. </s> <lb/> <s id="s.000705">ba&longs;is &longs;it rectangulum mnop, & altitudo eadem, quæ fru­<lb/> &longs;ti: <expan abbr="itemq,">itemque</expan> intelligatur conus, uel coni portio alb, cuius <lb/> ba&longs;is circulus, uel ellip&longs;is circa diametrum ab, & eadem al<lb/> <arrow.to.target n="marg86"/><lb/> titudo. </s> <s id="s.000706">ut igitur rectangula ab, ef, cd ad rectangulum ab, <lb/> ita pyramis q ad pyramidem alb; & ut circuli, uel ellip­<lb/> &longs;es ab, ef, cd ad ab circulum, uel ellip&longs;im, ita conus, uel co<lb/> ni portio q ad conum, uel coni portionem alb. </s> <s id="s.000707">conus <lb/> igitur, uel coni portio q ad conum, uel coni portionem <lb/> alb e&longs;t, ut pyramis q ad pyramidem alb. </s> <s id="s.000708">&longs;ed pyramis <lb/> alb ad pyramidem agb e&longs;t, ut altitudo ad altitudinem, ex <lb/> 20. huius: & ita e&longs;t conus, uel coni portio alb ad conum, <lb/> uel coni portionem agb ex 14. duodecimi elementorum, <lb/> & ex iis, quæ nos demon&longs;trauimus in commentariis in un­<lb/> decimam de conoidibus, & &longs;phæroidibus, propo&longs;itione <lb/> quarta. </s> <s id="s.000709">pyramis autem agb ad pyramidem cgd propor­<lb/> tionem habet compo&longs;itam ex proportione ba&longs;ium & pro <lb/> portione altitudinum, ex uige&longs;ima prima huius: & &longs;imili­<lb/> ter conus, uel coni portio agb ad conum, uel coni portio­<lb/> nem cgd proportionem habet <expan abbr="compo&longs;itã">compo&longs;itam</expan> ex ei&longs;dem pro­<lb/> portionibus, per ea, quæ in dictis commentariis demon­<lb/> &longs;trauimus, propo&longs;itione quinta, & &longs;exta: altitudo enim in<lb/> utri&longs;que eadem e&longs;t, & ba&longs;es inter &longs;e &longs;e eandem habent pro­<lb/> portionem. </s> <s id="s.000710">ergo ut pyramis agb ad pyramidem cgd, ita <lb/> e&longs;t conus, uel coni portio agb ad agd conum, uel coni <lb/> portionem: & per <expan abbr="conuer&longs;ion&etilde;">conuer&longs;ionem</expan> rationis, ut pyramis agb <lb/> ad <expan abbr="&longs;ru&longs;tũ">fru&longs;tum</expan> à pyramide ab&longs;ci&longs;&longs;um, ita conus uel coni portio <lb/> agb ad fru&longs;tum ad. <!-- KEEP S--></s> <s id="s.000711">ex æquali igitur, ut pyramis q ad fru­<lb/> &longs;tum à pyramide ab&longs;ci&longs;&longs;um, ita conus uel coni portio q ad <pb xlink:href="023/01/076.jpg"/>fru&longs;tum ad. <!-- KEEP S--></s> <s id="s.000712">Sed pyramis q æqualis e&longs;t fru&longs;to à pyramide <lb/> ab&longs;ci&longs;&longs;o, ut demon&longs;trauimus. </s> <s id="s.000713">ergo & conus, uel coni por­<lb/> tio q, cuius ba&longs;is ex tribus circulis, uel ellip&longs;ibus ab, ef, cd <lb/> con&longs;tat, & altitudo eadem, quæ fru&longs;ti: ip&longs;i fru&longs;to ad e&longs;t æ­<lb/> qualis. </s> <s id="s.000714">atque illud e&longs;t, quod demon&longs;trare oportebat.</s> </p> <p type="margin"> <s id="s.000715"><margin.target id="marg83"/>9 huius</s> </p> <p type="margin"> <s id="s.000716"><margin.target id="marg84"/>2. duode­<lb/>cimi.</s> </p> <p type="margin"> <s id="s.000717"><margin.target id="marg85"/>7. de co­<lb/> noidibus <lb/> & &longs;phæ­<lb/> roidibus</s> </p> <p type="margin"> <s id="s.000718"><margin.target id="marg86"/>6. II. duo <lb/> decimi</s> </p> <p type="head"> <s id="s.000719">THEOREMA XXI. PROPOSITIO XXVI.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000720">CVIVSLIBET fru&longs;ti à pyramide, uel cono, <lb/> uel coni portione ab&longs;cis&longs;i, centrum grauitatis e&longs;t <lb/> in axe, ita ut eo primum in duas portiones diui­<lb/> &longs;o, portio &longs;uperior, quæ minorem ba&longs;im attingit <lb/> ad portionem reliquam eam habeat proportio­<lb/> nem, quam duplum lateris, uel diametri maioris <lb/> ba&longs;is, vnà cum latere, uel diametro minoris, ip&longs;i <lb/> re&longs;pondente, habet ad duplum lateris, uel diame­<lb/> tri minoris ba&longs;is vnà <expan abbr="cũ">cum</expan> latere, uel diametro ma­<lb/> ioris: deinde à puncto diui&longs;ionis quarta parte &longs;u<lb/> perioris portionis in ip&longs;a &longs;umpta: & rur&longs;us ab in­<lb/> ferioris portionis termino, qui e&longs;t ad ba&longs;im maio<lb/> rem, &longs;umpta quarta parte totius axis: centrum &longs;it <lb/> in linea, quæ his finibus continetur, atque in eo li<lb/><lb/> tem propinquiorem minori ba&longs;i, <expan abbr="eãdem">eandem</expan> propor­<lb/> tionem habeat, quam fru&longs;tum ad <expan abbr="pyramid&etilde;">pyramidem</expan>, uel <lb/> conum, uel coni portionem, cuius ba&longs;is &longs;it ea­<lb/> dem, quæ ba&longs;is maior, & altitudo fru&longs;ti altitudini <lb/> æqualis.</s> </p> <pb pagenum="35" xlink:href="023/01/077.jpg"/> <p type="main"> <s id="s.000721">Sit fru&longs;tum ae a pyramide, quæ triangularem ba&longs;im ha­<lb/> beat ab&longs;ci&longs;&longs;um: cuius maior ba&longs;is triangulum abc, minor <lb/> def; & axis gh. </s> <s id="s.000722">ducto autem plano per axem & per <expan abbr="lineã">lineam</expan> <lb/> da, quod &longs;ectionem faciat dakl quadrilaterum; puncta <lb/> Kl lineas bc, ef bifariam &longs;ecabunt. </s> <s id="s.000723">nam cum gh &longs;it axis <lb/> fru&longs;ti: erit h centrum grauitatis trianguli abc: & g <lb/> <figure id="id.023.01.077.1.jpg" xlink:href="023/01/077/1.jpg"/><lb/> <arrow.to.target n="marg87"/><lb/> centrum trianguli def: cen­<lb/> trum uero cuiuslibet triangu<lb/> li e&longs;t in recta linea, quæ ab an­<lb/> gulo ip&longs;ius ad <expan abbr="dimidiã">dimidiam</expan> ba&longs;im <lb/> ducitur ex decimatertia primi <lb/> libri Archimedis de <expan abbr="c&etilde;tro">centro</expan> gra<lb/> <arrow.to.target n="marg88"/><lb/> uitatis planorum. </s> <s id="s.000724">quare <expan abbr="cen-trũ">cen­<lb/> trum</expan> grauitatis trapezii bcfe <lb/> e&longs;t in linea kl, quod &longs;it m: & à <lb/> puncto m ad axem ducta mn <lb/> ip&longs;i ak, uel dl æquidi&longs;tante; <lb/> erit axis gh diui&longs;us in portio­<lb/> nes gn, nh, quas diximus: ean <lb/> dem enim proportionem ha­<lb/> bet gn ad nh, <expan abbr="quã">quam</expan> lm ad mk. </s> <lb/> <s id="s.000725">At lm ad mK habet eam, <expan abbr="quã">quam</expan> <lb/> duplum lateris maioris ba&longs;is <lb/> bc una cum latere minoris ef <lb/> ad duplum lateris ef unà cum <lb/> latere bc, ex ultima eiu&longs;dem <lb/> libri Archimedis. <!-- KEEP S--></s> <s id="s.000726">Itaque à li­<lb/> nea ng ab&longs;cindatur, quarta <lb/> pars, quæ fit np: & ab axe hg ab&longs;cindatur itidem <lb/> quarta pars ho: & quam proportionem habet fru&longs;tum ad <lb/> pyramidem, cuius maior ba&longs;is e&longs;t triangulum abc, & alti­<lb/> tudo ip&longs;i æqualis; habeat op ad pq.</s> <s id="s.000727"> Dico centrum graui­<lb/> tatis fru&longs;ti e&longs;&longs;e in linea po, & in puncto q.</s> <s id="s.000728"> namque ip&longs;um <lb/> e&longs;&longs;e in linea gh manife&longs;te con&longs;tat. </s> <s id="s.000729">protractis enim fru&longs;ti pla<pb xlink:href="023/01/078.jpg"/>nis, quou&longs;que in unum punctum r conueniant; erit pyra­<lb/> midis abcr, & pyramidis defr grauitatis centrum in li­<lb/> nea rh. </s> <s id="s.000730">ergo & reliquæ magnitudinis, uidelicet fru&longs;ti cen­<lb/> trum in eadem linea nece&longs;&longs;ario comperietur. </s> <s id="s.000731">Iungantur <lb/> db, dc, dh, dm: & per lineas db, dc ducto altero plano <lb/> intelligatur fru&longs;tum in duas pyramides diui&longs;um: in pyra­<lb/> midem quidem, cuius ba&longs;is e&longs;t triangulum abc, uertex d: <lb/> & in eam, cuius idem uertex, & ba&longs;is trapezium bcfe. </s> <s id="s.000732">erit <lb/> igitur pyramidis abcd axis dh, & pyramidis bcfed axis <lb/> d m: atque erunt tres axes gh, dh, dm in eodem plano <lb/> daKl.</s> <s id="s.000733"> ducatur præterea per o linea &longs;t ip&longs;i aK <expan abbr="æquidi&longs;tãs">æquidi&longs;tans</expan>, <lb/> quæ lineam dh in u &longs;ecet: per p uero ducatur xy æquidi­<lb/> <figure id="id.023.01.078.1.jpg" xlink:href="023/01/078/1.jpg"/><lb/> &longs;tans eidem, &longs;ecansque dm in <lb/> z: & iungatur zu, quæ &longs;ecet <lb/> gh in <foreign lang="greek">f.</foreign> tran&longs;ibit ea per q: & <lb/> erunt <foreign lang="greek">f</foreign>q unum, atque idem <lb/> punctum; ut inferius appare­<lb/> bit. </s> <s id="s.000734">Quoniam igitur linea uo <lb/> <arrow.to.target n="marg89"/><lb/> æquidi&longs;tat ip&longs;i dg, erit du ad <lb/> uh, ut go ad oh. </s> <s id="s.000735">Sed go tri­<lb/> pla e&longs;t oh. </s> <s id="s.000736">quare & du ip&longs;ius <lb/> uh e&longs;t tripla: & ideo pyrami­<lb/> dis abcd centrum grauitatis <lb/> erit punctum u. </s> <s id="s.000737">Rur&longs;us quo­<lb/> niam zy ip&longs;i dl æquidi&longs;tat, dz <lb/> ad zm e&longs;t, ut ly ad ym: e&longs;tque <lb/> ly ad ym, ut gp ad pn. </s> <s id="s.000738">ergo <lb/> dz ad zm e&longs;t, ut gp ad pn. </s> <lb/> <s id="s.000739">Quòd cum gp &longs;it tripla pn; <lb/> erit etiam dz ip&longs;ius zm tri­<lb/> pla. </s> <s id="s.000740">atque ob eandem cau&longs;­<lb/> &longs;am punctum z e&longs;t <expan abbr="centrũ">centrum</expan> gra­<lb/> uitatis pyramidis bcfed. </s> <s id="s.000741">iun<lb/> cta igitur zu, in ea erit <expan abbr="c&etilde;trum">centrum</expan> <pb pagenum="36" xlink:href="023/01/079.jpg"/>grauitatis magnitudinis, quæ ex utri&longs;que pyramidibus <expan abbr="cõ">con</expan><lb/> &longs;tat; hoc e&longs;t ip&longs;ius fru&longs;ti. </s> <s id="s.000742">Sed fru&longs;ti centrum e&longs;t etiam in a­<lb/> xe gh. </s> <s id="s.000743">ergo in puncto <foreign lang="greek">f,</foreign> in quo lineæ zu, gh conueniunt. </s> <lb/> <s id="s.000744"><arrow.to.target n="marg90"/><lb/> Itaque u<foreign lang="greek">f</foreign> ad <foreign lang="greek">f</foreign>z eam proportionem habet, quam pyramis <lb/> bcfed ad pyramidem abcd. <!-- KEEP S--></s> <s id="s.000745">& componendo uz ad z<foreign lang="greek">f</foreign><lb/> eam habet, quam fru&longs;tum ad pyramidem abcd. <!-- KEEP S--></s> <s id="s.000746">Vt uero <lb/> uz ad z<foreign lang="greek">f</foreign>, ita op ad p<foreign lang="greek">f</foreign> ob &longs;imilitudinem triangulorum, <lb/> uo<foreign lang="greek">f</foreign>, zp<foreign lang="greek">f.</foreign> quare op ad p<foreign lang="greek">f</foreign> e&longs;t ut fru&longs;tum ad pyramidem <lb/> abcd. <!-- KEEP S--></s> <s id="s.000747">&longs;ed ita erat op ad pq.</s> <s id="s.000748"> æquales igitur &longs;unt p<foreign lang="greek">f</foreign>, pq: &<lb/> <arrow.to.target n="marg91"/><lb/> q<foreign lang="greek">f</foreign> unum atque idem punctum. </s> <s id="s.000749">ex quibus &longs;equitur lineam. </s> <lb/> <s id="s.000750">zu &longs;ecare op in q: & propterea <expan abbr="pũctum">punctum</expan> q ip&longs;ius fru&longs;ti gra­<lb/> uitatis centrum e&longs;&longs;e.</s> </p> <p type="margin"> <s id="s.000751"><margin.target id="marg87"/>3. diffi. </s> <s id="s.000752">hu<lb/> ius.</s> </p> <p type="margin"> <s id="s.000753"><margin.target id="marg88"/>Vltima <expan abbr="e-iu&longs;d&etilde;">e­<lb/> iu&longs;dem</expan> libri <lb/> Archime­<lb/> dis.<!-- KEEP S--></s> </p> <p type="margin"> <s id="s.000754"><margin.target id="marg89"/>2. &longs;exti.</s> </p> <p type="margin"> <s id="s.000755"><margin.target id="marg90"/>8. primi <lb/> libri Ar­<lb/> chimedis <lb/> de <expan abbr="c&etilde;tro">centro</expan> <lb/> grauta­<lb/> tis plano <lb/> rum</s> </p> <p type="margin"> <s id="s.000756"><margin.target id="marg91"/>7. quinti.</s> </p> <p type="main"> <s id="s.000757">Sit fru&longs;tum ag à pyramide, quæ quadrangularem ba&longs;im <lb/> habeat ab&longs;ci&longs;&longs;um, cuius maior ba&longs;is abcd, minor efgh, <lb/> & axis kl. <!-- REMOVE S-->diuidatur autem <expan abbr="primũ">primum</expan> kl, ita ut quam propor­<lb/> tionem habet duplum lateris ab unà cum latere ef ad du <lb/> plum lateris ef unà cum ab; habeat km ad ml. <!-- KEEP S--></s> <s id="s.000758">deinde à <lb/> <expan abbr="pũcto">puncto</expan> m ad k &longs;umatur quarta pars ip&longs;ius mk quæ &longs;it mn. </s> <lb/> <s id="s.000759">& rur&longs;us ab l &longs;umatur quarta pars totius axis lk, quæ &longs;it <lb/> lo. </s> <s id="s.000760">po&longs;tremo fiat on ad np, ut fru&longs;tum ag ad <expan abbr="pyramid&etilde;">pyramidem</expan>, <lb/> cuius ba&longs;is &longs;it eadem, quæ fru&longs;ti, & altitudo æqualis. </s> <s id="s.000761">Dico <lb/> punctum p fru&longs;ti ag grauitatis centrum e&longs;&longs;e. </s> <s id="s.000762">ducantur <lb/> enim ac, eg: & intelligantur duo fru&longs;ta triangulares ba­<lb/> &longs;es habentia, quorum alterum lf ex ba&longs;ibus abc, efg <expan abbr="cõ-&longs;tet">con­<lb/> &longs;tet</expan>; alterum lh ex ba&longs;ibus acd, egh. </s> <s id="s.000763"><expan abbr="Sitq;">Sitque</expan> fru&longs;ti lf axis <lb/> qr; in quo grauitatis centrum s: fru&longs;ti uero lh axis tu, & <lb/> x grauitatis centrum: deinde iungantur ur, tq, xs. </s> <s id="s.000764">tran&longs;i­<lb/> bit ur per l: quoniam l e&longs;t centrum grauitatis quadran­<lb/> guli abcd: & puncta ru grauitatis centra triangulorum <lb/> abc, acd; in quæ quadrangulum ip&longs;um diuiditur. </s> <s id="s.000765">eadem <lb/> quoque ratione tq per punctum k tran&longs;ibit. </s> <s id="s.000766">At uero pro<lb/> portiones, ex quibus fru&longs;torum grauitatis centra inquiri­<lb/> mus, eædem &longs;unt in toto fru&longs;to ag, & in fru&longs;tis lf, lh. </s> <s id="s.000767">Sunt <lb/> enim per octauam huius quadrilatera abcd, efgh &longs;imilia: <pb xlink:href="023/01/080.jpg"/><expan abbr="itemq;">itemque</expan> &longs;imilia triangula abc, efg: & acd, egh. </s> <s id="s.000768"><expan abbr="idcir-coq;">idcir­<lb/> coque</expan> latera &longs;ibi ip&longs;is re&longs;pondentia eandem inter &longs;e&longs;e pro­<lb/> portionem &longs;eruant. </s> <s id="s.000769">Vt igitur duplum lateris ab unà <lb/> cum latere ef ad duplum lateris ef unà cum ab, ita e&longs;t <lb/> <figure id="id.023.01.080.1.jpg" xlink:href="023/01/080/1.jpg"/><lb/> duplum ad late­<lb/> ris una cum late­<lb/> re eh ad duplum <lb/> eh unà cum ad: <lb/> & ita in aliis. </s> <lb/> <s id="s.000770">Rur&longs;us fru&longs;tum <lb/> ag ad <expan abbr="pyramid&etilde;">pyramidem</expan>, <lb/> cuius eadem e&longs;t <lb/> ba&longs;is, & æqualis <lb/> altitudo eandem <lb/> <expan abbr="proportion&etilde;">proportionem</expan> ha<lb/> bet, quam <expan abbr="fru&longs;tũ">fru&longs;tum</expan> <lb/> lf ad <expan abbr="pyramid&etilde;">pyramidem</expan>, <lb/> quæ e&longs;t <expan abbr="ead&etilde;">eadem</expan> ba­<lb/> &longs;i, & æquali alti­<lb/> tudine: & &longs;imili­<lb/> ter quam lh fru­<lb/> &longs;tum ad pyrami­<lb/> dem, quæ ex <expan abbr="ea-d&etilde;">ea­<lb/> dem</expan> ba&longs;i, & æquali <lb/> altitudine con­<lb/> &longs;tat. </s> <s id="s.000771">nam &longs;i inter <lb/> ip&longs;as ba&longs;es me­<lb/> diæ proportio­<lb/> nales con&longs;tituan<lb/> tur, tres ba&longs;es &longs;imul &longs;umptæ ad maiorem ba&longs;im in om­<lb/> nibus eodem modo &longs;e habebunt. </s> <s id="s.000772">Vnde fit, ut axes Kl, <lb/> qr, tu à punctis psx in eandem proportionem &longs;ecen­<lb/> <arrow.to.target n="marg92"/><lb/>tur. </s> <s id="s.000773">ergo linea xs per p tran&longs;ibit: & lineæ ru, sx, qt in­<lb/> ter &longs;e æquidi&longs;tantes erunt. </s> <s id="s.000774">Itaque cum fru&longs;ti ag latera pro­<pb pagenum="37" xlink:href="023/01/081.jpg"/>ducta &longs;uerint, ita ut in unum punctum y coeant, erunt <expan abbr="triã">trian</expan><lb/> gula uyl, xyp, tyk inter &longs;e &longs;imilia: & &longs;imilia etiam triangu<lb/> la lyr, pys, kyq quare ut in 19 huius, demon&longs;trabitur <lb/> xp, ad ps: <expan abbr="itemq;">itemque</expan> tk ad kq eandem habere <expan abbr="proportion&etilde;">proportionem</expan>, <lb/> quam ul ad lr. </s> <s id="s.000775">Sed ut ul ad lr, ita e&longs;t triangulum abc ad <lb/> triangulum acd: & ut tk ad Kq, ita triangulum efg ad <lb/> triangulum egh. </s> <s id="s.000776">Vt autem triangulum abc ad triangu­<lb/> lum acd, ita pyramis abcy ad pyramidem acdy. </s> <s id="s.000777">& ut <lb/> triangulum efg ad triangulum egh, ita pyramis efgy <lb/> ad pyramidem eghy; ergo ut pyramis abcy ad <expan abbr="pyramid&etilde;">pyramidem</expan> <lb/> <arrow.to.target n="marg93"/><lb/> a cdy, ita pyramis efgy ad pyramidem eghy. </s> <s id="s.000778">reliquum <lb/> igitur <expan abbr="fru&longs;tũ">fru&longs;tum</expan> lf ad reliquum <expan abbr="fru&longs;tũ">fru&longs;tum</expan> lh e&longs;t ut pyramis abcy <lb/> ad pyramidem acdy, hoc e&longs;t ut ul ad r, & ut xp ad ps. </s> <lb/> <s id="s.000779">Quòd cum fru&longs;ti lf centrum grauitatis &longs;its: & fru&longs;ti lh &longs;it <lb/> <arrow.to.target n="marg94"/><lb/> centrum x: con&longs;tat punctum p totius fru&longs;ti ag grauitatis <lb/> e&longs;&longs;e centrum. </s> <s id="s.000780">Eodem modo fiet demon&longs;tratio etiam in <lb/> aliis pyramidibus.</s> </p> <p type="margin"> <s id="s.000781"><margin.target id="marg92"/>a. </s> <s id="s.000782">&longs;exti.</s> </p> <p type="margin"> <s id="s.000783"><margin.target id="marg93"/>19. quinti</s> </p> <p type="margin"> <s id="s.000784"><margin.target id="marg94"/>8. Archi­<lb/> medis.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000785">Sit fru&longs;tum ad à cono, uel coni portione ab&longs;ci&longs;&longs;um, eu­<lb/> ius maior ba&longs;is circulus, uel ellip&longs;is circa diametrum ab; <lb/> minor circa diametrum cd: & axis ef. </s> <s id="s.000786">diuidatur <expan abbr="aut&etilde;">autem</expan> ef <lb/> in g, ita ut eg ad gf eandem proportionem habeat, quam <lb/> duplum diametri ab unà cum diametro ed ad duplum cd <lb/> unà cum ab. </s> <s id="s.000787"><expan abbr="Sitq;">Sitque</expan> gh quarta pars lineæ ge: & &longs;it &longs; K item <lb/> quarta pars totius fe axis. </s> <s id="s.000788">Rur&longs;us quam proportionem <lb/> habet fru&longs;tum ad ad conum, uel coni portionem, in <expan abbr="ead&etilde;">eadem</expan> <lb/> ba&longs;i, & æquali altitudine, habeat linea Kh ad hl. <!-- KEEP S--></s> <s id="s.000789">Dico pun­<lb/> ctum l fru&longs;ti ad grauitatis centrum e&longs;&longs;e. </s> <s id="s.000790">Si enim fieri po­<lb/> te&longs;t, &longs;it m centrum: <expan abbr="producaturq;">producaturque</expan> lm extra fru&longs;tum in n: <lb/> & ut nl ad lm, ita fiat circulus, uel ellip&longs;is circa <expan abbr="diametrũ">diametrum</expan> <lb/> ab ad aliud &longs;pacium, in quo &longs;it o. </s> <s id="s.000791">Itaque in circulo, uel <lb/> ellip&longs;i circa diametrum ab rectilinea figura plane de&longs;cri­<lb/> batur, ita ut quæ relinquuntur portiones &longs;int o &longs;pacio mi­<lb/> nores: & intelligatur pyramis apb, ba&longs;im habens rectili­<lb/> neam figuram in circulo, uel ellip&longs;i ab de&longs;criptam: à qua <pb xlink:href="023/01/082.jpg"/>fru&longs;tum pyramidis &longs;it ab&longs;ci&longs;&longs;um. </s> <s id="s.000792">erit ex iis quæ proxime <lb/> tradidimus, fru&longs;ti pyramidis ad centrum grauitatis l. <!-- KEEP S--></s> <s id="s.000793">Quo<lb/> niam igitur portiones &longs;pacio o minores &longs;unt; habebit cir <lb/> <figure id="id.023.01.082.1.jpg" xlink:href="023/01/082/1.jpg"/><lb/> culus, uel ellip&longs;is ab ad <lb/> portiones dictas <expan abbr="maior&etilde;">maiorem</expan> <lb/> proportionem, quàm nl <lb/> ad lm. </s> <s id="s.000794">&longs;ed ut circulus, uel <lb/> ellip&longs;is ab ad portiones, <lb/> ita apb conus, uel coni <lb/> portio ad &longs;olidas portio­<lb/> nes, id quod &longs;upra demon <lb/> &longs;tratum e&longs;t: & ut circulus <lb/> <arrow.to.target n="marg95"/><lb/> uel ellip&longs;is cd ad portio­<lb/> nes, quæ ip &longs;i in&longs;unt, ita co<lb/> nus, uel coni portio cpd <lb/> ad &longs;olidas ip&longs;ius portio­<lb/> nes. </s> <s id="s.000795">Quòd cum figuræ in <lb/> circulis, uel ellip&longs;ibus ab <lb/> cd de&longs;criptæ &longs;imiles &longs;int, <lb/> erit proportio circuli, uel <lb/> ellip&longs;is ab ad &longs;uas portio <lb/> nes, <expan abbr="ead&etilde;">eadem</expan>, quæ circuli uel <lb/> ellip&longs;is cd ad &longs;uas. </s> <s id="s.000796">ergo <lb/> conus, uel coni portio ap<lb/> b ad portiones &longs;olidas <expan abbr="eã-dem">ean­<lb/> dem</expan> habet <expan abbr="proportion&etilde;">proportionem</expan>, <lb/> quam conus, uel coni por<lb/> tio cpd ad &longs;olidas ip&longs;ius <lb/> <arrow.to.target n="marg96"/><lb/> portiones. </s> <s id="s.000797">reliquum igi­<lb/> tur coni, uel coni portionis <expan abbr="fru&longs;tũ">fru&longs;tum</expan>, &longs;cilicet ad ad reliquas <lb/> portiones &longs;olidas in ip&longs;o contentas eandem <expan abbr="proportion&etilde;">proportionem</expan> <lb/> habet, quam conus, uel coni portio apb ad &longs;olidas portio<lb/>nes: hoc e&longs;t eandem, quam circulus, uel ellip&longs;is ab ad por<lb/> tiones planas. </s> <s id="s.000798">quare fru&longs;tum coni, uel coni portionis ad <pb pagenum="38" xlink:href="023/01/083.jpg"/>ad portiones &longs;olidas maiorem habet <expan abbr="proportion&etilde;">proportionem</expan>, quàm <lb/> nl ad lm: & diuidendo fru&longs;tum pyramidis ad dictas por­<lb/> tiones maiorem proportionem habet, quàm nm ad ml. <!-- KEEP S--></s> <lb/> <s id="s.000799">fiat igitur ut fru&longs;tum pyramidis ad portiones, ita qm ad <lb/> m l. <!-- KEEP S--></s> <s id="s.000800">Itaque quoniam à fru&longs;to coni, uel coni portionis ad, <lb/> cuius grauitatis centrum e&longs;t m, aufertur fru&longs;tum pyrami­<lb/> dis habens centrum l; erit reliquæ magnitudinis, quæ ex <lb/> portionibus &longs;olidis con&longs;tat; grauitatis <expan abbr="c&etilde;trum">centrum</expan> in linea lm <lb/> producta, atque in puncto q, extra figuram po&longs;ito: quod <lb/> fieri nullo modo pote&longs;t. </s> <s id="s.000801">relinquitur ergo, ut punctum l &longs;it <lb/> fru&longs;ti ad grauitatis centrum. </s> <s id="s.000802">quz omnia demon&longs;tranda <lb/> proponebantur.</s> </p> <p type="margin"> <s id="s.000803"><margin.target id="marg95"/>22. huius</s> </p> <p type="margin"> <s id="s.000804"><margin.target id="marg96"/>19. quínti</s> </p> <p type="head"> <s id="s.000805">THEOREMA XXII. PROPOSITIO XXVII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000806">OMNIVM &longs;olidorum in &longs;phæra de&longs;cripto­<lb/> rum, quæ æqualibus, & &longs;imilibus ba&longs;ibus conti­<lb/> nentur, centrum grauitatis e&longs;t idem, quod &longs;phæ­<lb/> ræ centrum.</s> </p> <p type="main"> <s id="s.000807">Solida eiu&longs;modi corpora regularia appellare &longs;olent, de <lb/> quibus agitur in tribus ultimis libris elementorum: &longs;unt <lb/> autem numero quinque, tetrahedrum, uel pyramis, hexa­<lb/> hedrum, uel cubus, octahedrum, dodecahedrum, & ico&longs;a­<lb/> hedrum.</s> </p> <p type="main"> <s id="s.000808">Sit primo abcd pyramis <expan abbr="ĩ">im</expan> &longs;phæra de&longs;cripta, cuius &longs;phæ<lb/> ræ centrum &longs;it e. </s> <s id="s.000809">Dico e pyramidis abcd grauitatis e&longs;&longs;e <lb/> centrum. </s> <s id="s.000810">Si enim iuncta dc producatur ad ba&longs;im abc in <lb/> f; ex iis, quæ demon&longs;trauit Campanus in quartodecimo li<lb/> bro elementorum, propo&longs;itione decima quinta, & decima <lb/> &longs;eptima, erit f centrum circuli circa triangulum abc de­<lb/> &longs;cripti: atque erit ef &longs;exta pars ip&longs;ius &longs;phæræ axis. </s> <s id="s.000811">quare <lb/> ex prima huius con&longs;tat trianguli abc grauitatis centrum <lb/> e&longs;&longs;e punctum f: & idcirco lineam df e&longs;&longs;e pyramidis axem. <pb xlink:href="023/01/084.jpg"/><figure id="id.023.01.084.1.jpg" xlink:href="023/01/084/1.jpg"/><lb/> At cum ef &longs;it &longs;exta pars axis <lb/> &longs;phæræ, erit d tripla ef. </s> <s id="s.000812">ergo <lb/> punctum e e&longs;t grauitatis cen­<lb/> trum ip&longs;ius pyramidis: quod <lb/> in uige&longs;ima &longs;ecunda huius de­<lb/> mon&longs;tratum &longs;uit. </s> <s id="s.000813">Sed e e&longs;t cen<lb/> trum &longs;phæræ. </s> <s id="s.000814">Sequitur igitur, <lb/> ut centrum grauitatis pyrami­<lb/> dis in &longs;phæra de&longs;criptæ idem <lb/> &longs;it, quod ip&longs;ius &longs;phæræ cen­<lb/> trum.</s> </p> <p type="main"> <s id="s.000815">Sit cubus in &longs;phæra de&longs;criptus ab, & oppo&longs;itorum pla­<lb/> norum lateribus bifariam diui&longs;is, per puncta diui&longs;ionum <lb/> plana ducantur, ut communis ip&longs;orum &longs;ectio &longs;it recta li­<lb/> nea cd. <!-- KEEP S--></s> <s id="s.000816">Itaque &longs;i ducatur ab, &longs;olidi &longs;cilicet diameter, lineæ <lb/> ab, cd ex trige&longs;imanona undecimi &longs;e&longs;e bifariam &longs;ecabunt. </s> <lb/> <s id="s.000817"><figure id="id.023.01.084.2.jpg" xlink:href="023/01/084/2.jpg"/><lb/> &longs;ecent autem in puncto e. </s> <s id="s.000818">erit, <lb/> e <expan abbr="centrũ">centrum</expan> grauitatis &longs;olidi ab, <lb/> id quod demon&longs;tratum e&longs;t in <lb/> octaua huius. </s> <s id="s.000819">Sed quoniam ab <lb/> e&longs;t &longs;phæræ diametro æqualis, <lb/> ut in decima quinta propo&longs;i­<lb/> tione tertii decimi libri <expan abbr="elem&etilde;">elemen</expan><lb/> torum o&longs;tenditur: punctum e <lb/> &longs;phæræ quoque centrum erit. </s> <lb/> <s id="s.000820">Cubi igitur in &longs;phæra de&longs;cri­<lb/> pti grauitatis centrum idem <lb/> e&longs;t, quod centrum ip&longs;ius &longs;phæræ.</s> </p> <p type="main"> <s id="s.000821">Sit octahedrum abcdef, in &longs;phæra de&longs;criptum, cuius <lb/> &longs;phæræ centrum &longs;it g. </s> <s id="s.000822">Dico punctum g ip&longs;ius octahedri <lb/> grauitatis centrum e&longs;&longs;e. </s> <s id="s.000823">Con&longs;tat enim ex iis, quæ demon­<lb/> &longs;trata &longs;unt à Campano in quinto decimo libro elemento­<lb/> rum, propo&longs;itione &longs;extadecima eiu&longs;modi &longs;olidum diuidi <lb/> in duas pyramides æquales, & &longs;imiles; uidelicet in pyrami­ <pb pagenum="39" xlink:href="023/01/085.jpg"/>dem, cuius ba&longs;is e&longs;t quadratum abcd, & altitudo eg: & <lb/> in pyramidem, cuius <expan abbr="ead&etilde;">eadem</expan> ba&longs;is, <expan abbr="altitudoq;">altitudoque</expan> fg; ut &longs;int eg, <lb/> gf &longs;emidiametri &longs;phæræ, & linea una. </s> <s id="s.000824"><expan abbr="Cũ">Cum</expan> igitur g &longs;it &longs;phæ­<lb/> ræ centrum, erit etiam centrum circuli, qui circa <expan abbr="quadratũ">quadratum</expan> <lb/> abcd de&longs;cribitur: & propterea eiu&longs;dem quadrati grauita<lb/> tis centrum: quod in prima propo&longs;itione huius demon­<lb/> &longs;tratum e&longs;t. </s> <s id="s.000825">quare pyramidis abcde axis erit eg: & pyra<lb/> midis abcdf axis fg. <!-- KEEP S--></s> <s id="s.000826">Itaque &longs;it h centrum grauitatis py­<lb/> ramidis abcde, & pyramidis abcdf centrum &longs;it <emph type="italics"/>K:<emph.end type="italics"/> per­<lb/> &longs;picuum e&longs;t ex uige&longs;ima &longs;ecunda propo&longs;itione huius, <expan abbr="lineã">lineam</expan> <lb/> <figure id="id.023.01.085.1.jpg" xlink:href="023/01/085/1.jpg"/><lb/> ch triplam e&longs;&longs;e hg: <expan abbr="cõ">com</expan><lb/> <expan abbr="ponendoq;">ponendoque</expan> eg ip&longs;ius g <lb/> h quadruplam. </s> <s id="s.000827">& <expan abbr="ead&etilde;">eadem</expan> <lb/> ratione fg <expan abbr="quadruplã">quadruplam</expan> <lb/> ip&longs;ius gk quod cum e <lb/> g, gf &longs;int æquales, & h <lb/> g, g <emph type="italics"/>K<emph.end type="italics"/> nece&longs;&longs;ario æqua­<lb/> les erunt. </s> <s id="s.000828">ergo ex quar<lb/> ta propo&longs;itione primi <lb/> libri Archimedis de <expan abbr="c&etilde;-tro">cen­<lb/> tro</expan> grauitatis <expan abbr="planorũ">planorum</expan>, <lb/> totius octahedri, quod <lb/> ex dictis pyramidibus <lb/> con&longs;tat, centrum graui <lb/> tatis erit punctum g idem, quod ip&longs;ius &longs;phæræ centrum.</s> </p> <p type="main"> <s id="s.000829">Sit ico&longs;ahedrum ad de&longs;criptum in &longs;phæra, cuius <expan abbr="centrũ">centrum</expan> <lb/> &longs;it g. <!-- KEEP S--></s> <s id="s.000830">Dico g ip&longs;ius ico&longs;ahedri grauitatis e&longs;&longs;e centrum. </s> <s id="s.000831">Si <lb/> enim ab angulo a per g ducatur recta linea u&longs;que ad &longs;phæ<lb/> ræ &longs;uperficiem; con&longs;tat ex &longs;exta decima propo&longs;itione libri <lb/> tertii decimi elementorum, cadere eam in angulum ip&longs;i a <lb/> oppo&longs;itum. </s> <s id="s.000832">cadat in d: <expan abbr="&longs;itq;">&longs;itque</expan> una aliqua ba&longs;is ico&longs;ahedri tri­<lb/> angulum abc: & iunctæ bg, producantur, & cadant in <lb/> angulos ef, ip&longs;is bc oppo&longs;itos. </s> <s id="s.000833">Itaque per triangula <lb/> abc, def ducantur plana &longs;phæram &longs;ecantia.</s> <s id="s.000834"> erunt hæ &longs;e- <pb xlink:href="023/01/086.jpg"/>ctiones circuli ex prima propo&longs;itione &longs;phæricorum Theo<lb/> do&longs;ii: unus quidem circa triangulum abc de&longs;criptus: al­<lb/> ter uero circa def: & quoniam triangula abc, def æqua­<lb/> lia &longs;unt, & &longs;imilia; erunt ex prima, & &longs;ecunda propo&longs;itione <lb/> duodecimi libri elementorum, circuli quoque inter &longs;e &longs;e <lb/> æquales. </s> <s id="s.000835">po&longs;tremo a centro g ad circulum abc perpendi<lb/> cularis ducatur gh; & alia perpendicularis ducatur ad cir<lb/> culum def, quæ &longs;it gk; & iungantur ah, dk per&longs;picuum <lb/> e&longs;t ex corollario primæ &longs;phæricorum Theodo&longs;ii, punctum <lb/> h centrum e&longs;&longs;e circuli abc, & k centrum circuli def. </s> <s id="s.000836">Quo<lb/> niam igitur triangulorum gah, gdK latus ag e&longs;t æquale la<lb/> teri gd; &longs;unt enim à centro &longs;phæræ ad &longs;uperficiem: atque <lb/> e&longs;t ah æquale dk: & ex &longs;exta propo&longs;itione libri primi &longs;phæ<lb/> ricorum Theodo&longs;ii gh ip&longs;i gK: triangulum gah æquale <lb/> erit, & &longs;imile gdk triangulo: & angulus agh æqualis an­<lb/> <arrow.to.target n="marg97"/><lb/> gulo dg <emph type="italics"/>K.<emph.end type="italics"/> &longs;ed anguli agh, hgd &longs;unt æquales duobus re­<lb/> ctis. </s> <s id="s.000837">ergo & ip&longs;i hgd, dgk duobus rectis æquales erunt. </s> <lb/> <s id="s.000838"><arrow.to.target n="marg98"/><lb/> & idcirco hg, g <emph type="italics"/>K<emph.end type="italics"/> una, atque eadem erit linea. </s> <s id="s.000839">cum autem <lb/> <figure id="id.023.01.086.1.jpg" xlink:href="023/01/086/1.jpg"/><lb/> h &longs;it <expan abbr="centrũ">centrum</expan> circuli, & tri­<lb/> anguli abc grauitatis cen<lb/> <expan abbr="trũ">trum</expan> probabitur ex iis, quæ <lb/> in prima propo&longs;itione hu<lb/> ius tradita &longs;unt. </s> <s id="s.000840">quare gh <lb/> erit pyramidis abcg axis. </s> <lb/> <s id="s.000841">& ob eandem cau&longs;&longs;am gk <lb/> axis pyramidis defg. <!-- KEEP S--></s> <s id="s.000842">lta­<lb/> que centrum grauitatls py<lb/> ramidis abcg &longs;it <expan abbr="pũctum">punctum</expan> <lb/> l, & pyramidis defg &longs;it m. </s> <lb/> <s id="s.000843">Similiter ut &longs;upra demon­<lb/> &longs;trabimus mg, gl inter &longs;e æquales e&longs;&longs;e, & punctum g graui <lb/> tatis centrum magnitudinis, quæ ex utri&longs;que pyramidibus <lb/> con&longs;tat. </s> <s id="s.000844">eodem modo demon&longs;trabitur, quarumcunque <lb/> duarum pyramidum, quæ opponuntur, grauitatis <expan abbr="centrũ">centrum</expan> <pb pagenum="40" xlink:href="023/01/087.jpg"/>e&longs;&longs;e punctum g. <!-- KEEP S--></s> <s id="s.000845">Sequitur ergo ut ico&longs;ahedri centrum gra<lb/> uitatis &longs;it idem, quod ip&longs;ius &longs;phæræ centrum.</s> </p> <p type="margin"> <s id="s.000846"><margin.target id="marg97"/>13. primi</s> </p> <p type="margin"> <s id="s.000847"><margin.target id="marg98"/>14. primi</s> </p> <p type="main"> <s id="s.000848">Sit dodecahedrum af in &longs;phæra de&longs;ignatum, &longs;itque &longs;phæ<lb/> ræ centrum m. </s> <s id="s.000849">Dico m centrum e&longs;&longs;e grauitatis ip&longs;ius do­<lb/> decahedri. </s> <s id="s.000850">Sit enim pentagonum abcde una ex duode­<lb/> cim ba&longs;ibus &longs;olidi af: & iuncta am producatur ad &longs;phæræ <lb/> &longs;uperficiem. </s> <s id="s.000851">cadet in angulum ip&longs;i a oppo&longs;itum; quod col­<lb/> ligitur ex decima &longs;eptima propo&longs;itione tertiidecimi libri <lb/> elementorum. </s> <s id="s.000852">cadat in f. </s> <s id="s.000853">at &longs;i ab aliis angulis bcde per <expan abbr="c&etilde;">cen</expan><lb/> trum itidem lineæ ducantur ad &longs;uperficiem &longs;phæræ in pun<lb/> cta ghkl; cadent hæ in alios angulos ba&longs;is, quæ ip&longs;i abcd <lb/> ba&longs;i opponitur. </s> <s id="s.000854">tran&longs;eant ergo per pentagona abcde, <lb/> fghKl plana &longs;phæram &longs;ecantia, quæ facient &longs;ectiones cir­<lb/> culos æquales inter &longs;e &longs;e: po&longs;tea ducantur ex centro &longs;phæræ <lb/> <figure id="id.023.01.087.1.jpg" xlink:href="023/01/087/1.jpg"/><lb/> m perpendiculares ad pla­<lb/> na dictorum <expan abbr="circulorũ">circulorum</expan>; ad <lb/> circulum quidem abcde <lb/> perpendicularis mn: & ad <lb/> circulum fghKl ip&longs;a mo, <lb/> <arrow.to.target n="marg99"/><lb/> erunt puncta no <expan abbr="circulorũ">circulorum</expan> <lb/> centra: & lineæ mn, mo in<lb/> ter &longs;e æquales: quòd circu­<lb/> <arrow.to.target n="marg100"/><lb/> li æquales &longs;int. </s> <s id="s.000855">Eodem mo<lb/> do, quo &longs;upra, demon&longs;trabi<lb/> mus lineas mn, mo in <expan abbr="unã">unam</expan> <lb/> atque eandem lineam con­<lb/> uenire. </s> <s id="s.000856">ergo cum puncta no &longs;int centra circulorum, con­<lb/> &longs;tat ex prima huius & <expan abbr="pentagonorũ">pentagonorum</expan> grauitatis e&longs;&longs;e centra: <lb/> <expan abbr="idcircoq;">idcircoque</expan> mn, mo pyramidum abcdem, fghklm axes. </s> <lb/> <s id="s.000857">ponatur abcdem pyramidis grauitatis centrum p: & py<lb/> ramidis fghklm ip&longs;um q centrum. </s> <s id="s.000858">erunt pm, mq æqua­<lb/> les, & punctum m grauitatis centrum magnitudinis, quæ <lb/> ex ip&longs;is pyramidibus con&longs;tat. </s> <s id="s.000859"><expan abbr="eod&etilde;">eodem</expan> modo probabitur qua­<lb/> rumlibet pyramidum, quæ è regione opponuntur, <expan abbr="centrũ">centrum</expan> <pb xlink:href="023/01/088.jpg"/>grauitatis e&longs;&longs;e punctum m. </s> <s id="s.000860">patet igitur totius dodecahe­<lb/> dri, centrum grauitatis <expan abbr="id&etilde;">idem</expan> e&longs;&longs;e, quod & &longs;phæræ ip&longs;um com<lb/> prehendentis centrum. </s> <s id="s.000861">quæ quidem omnia demon&longs;tra&longs;&longs;e <lb/> oportebat.</s> </p> <p type="margin"> <s id="s.000862"><margin.target id="marg99"/>corol. </s> <s id="s.000863">pri<lb/> mæ &longs;phæ<lb/> ricorum <lb/> Theod.<!-- REMOVE S--><margin.target id="marg100"/>6. primi <lb/>sphærico<lb/> rum.</s> </p> <p type="head"> <s id="s.000864">PROBLEMA VI. PROPOSITIO XXVIII.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000865">DATA qualibet portione conoidis rectangu<lb/> li, ab&longs;ci&longs;&longs;a plano ad axem recto, uel non recto; fie­<lb/> ri pote&longs;t, ut portio &longs;olida in&longs;cribatur, uel circum­<lb/> &longs;cribatur ex cylindris, uel cylindri portionibus, <lb/> æqualem habentibus altitudinem, ita ut recta li­<lb/> nea, quæ inter centrum grauitatis portionis, & <lb/> figuræ in&longs;criptæ, uel circum&longs;criptæ interiicitur, <lb/> &longs;it minor qualibet recta linea propo&longs;ita.</s> </p> <p type="main"> <s id="s.000866">Sit portio conoidis rectanguli abc, cuius axis bd, <expan abbr="gra-uitatisq;">gra­<lb/> uitatisque</expan> centrum e: & &longs;it g recta linea propo&longs;ita. </s> <s id="s.000867">quam ue<lb/> ro proportionem habet linea be ad lineam g, eandem ha­<lb/> beat portio conoidis ad &longs;olidum h: & circum&longs;cribatur por<lb/> tioni figura, &longs;icuti dictum e&longs;t, ita ut portiones reliquæ &longs;int <lb/> &longs;olido h minores: cuius quidem figuræ centrum grauitatis <lb/> &longs;it punctum k. </s> <s id="s.000868">Dico <expan abbr="lineã">lineam</expan> ke minorem e&longs;&longs;e linea g propo­<lb/> &longs;ita. </s> <s id="s.000869">ni&longs;i enim &longs;it minor, uel æqualis, uel maior erit. </s> <s id="s.000870">& quo­<lb/> niam figura circum&longs;cripta ad reliquas portiones maiorem <lb/> <arrow.to.target n="marg101"/><lb/> proportionem habet, quàm portio conoidis ad &longs;olidum h; <lb/> hoc e&longs;t maiorem, quàm bc ad g: & be ad g non minorem <lb/> habet proportionem, quàm ad ke, propterea quod ke non <lb/> ponitur minor ip&longs;a g: habebit figura circum&longs;cripta ad por<lb/> tiones reliquas maiorem proportionem quàm be ad ek: <lb/> <arrow.to.target n="marg102"/><lb/> & diuidendo portio conoidis ad reliquas portiones habe­<lb/> bit maiorem, quàm bk ad Ke. </s> <s id="s.000871">quare &longs;i fiat ut portio co­ <pb pagenum="41" xlink:href="023/01/089.jpg"/>noidis ad portiones reliquas, ita alia linea, quæ &longs;it lk ad <lb/> ke: erit lk maior, quam bk: & ideo punctum l extra por­<lb/> <figure id="id.023.01.089.1.jpg" xlink:href="023/01/089/1.jpg"/><lb/> tionem cadet. </s> <s id="s.000872"><expan abbr="Quoniã">Quoniam</expan> <lb/> igitur à figura circum­<lb/> &longs;cripta, cuius grauitatis <lb/> centrum e&longs;t k, aufertur <lb/> portio conoidis, cuius <lb/> centrum e. </s> <s id="s.000873"><expan abbr="habetq;">habetque</expan> lK <lb/> ad Ke eam proportio­<lb/> nem, quam portio co­<lb/> noidis ad reliquas por­<lb/> tiones; erit punctum l <lb/> extra portionem <expan abbr="cad&etilde;s">cadens</expan>, <lb/> centrum magnitudinis <lb/> ex reliquis portionibus compo&longs;itæ. </s> <s id="s.000874">illud autem fieri nullo <lb/> modo pote&longs;t. </s> <s id="s.000875">quare con&longs;tat lineam ke ip&longs;a g linea propo&longs;i<lb/> ta minorem e&longs;&longs;e.</s> </p> <p type="margin"> <s id="s.000876"><margin.target id="marg101"/>8. quínti.</s> </p> <p type="margin"> <s id="s.000877"><margin.target id="marg102"/>29. quínti <lb/> ex tradi­<lb/> tione <expan abbr="Cã-pani">Cam­<lb/>pani </expan> .</s> </p> <p type="main"> <s id="s.000878">Rur&longs;us in&longs;cribatur portioni figura, uidelicet cylindrus <lb/> <figure id="id.023.01.089.2.jpg" xlink:href="023/01/089/2.jpg"/><lb/> mn, ut &longs;it ip&longs;ius altitudo <lb/> æqualis dimidio axis bd: <lb/> & quam proportionem <lb/> habet be ad g, habeat mn <lb/> cylindrus ad &longs;olidum o. </s> <lb/> <s id="s.000879">in&longs;cribatur deinde eidem <lb/> alia figura, ita ut portio­<lb/> nes reliquæ &longs;int &longs;olido o <lb/> minores: & centrum gra<lb/> uitatis figuræ &longs;it p. </s> <s id="s.000880">Dico <lb/> lineam pe ip&longs;a g <expan abbr="minor&etilde;">minorem</expan> <lb/> e&longs;&longs;e. </s> <s id="s.000881">&longs;i enim non &longs;it mi­<lb/> nor, eodem, quo &longs;upra modo demon&longs;trabimus figuram in <lb/> &longs;criptam ad reliquas portiones maiorem proportionem <lb/> habere, quàm be ad ep. </s> <s id="s.000882">& &longs;i fiat alia linea le ad ep, ut e&longs;t <lb/> figura in&longs;cripta ad reliquas portiones, <expan abbr="pũctum">punctum</expan> l extra por <pb xlink:href="023/01/090.jpg"/>tionem cadet: Itaque cum à portione conoidis, cuius gra­<lb/> uitatis centrum e auferatur in&longs;cripta figura, centrum ha­<lb/> bens p: & &longs;it le ad ep, ut figura in&longs;cripta ad portiones reli<lb/> quas: erit magnitudinis, quæ ex reliquis portionibus con<lb/> &longs;tat, centrum grauitatis punctum l, extra portionem ca­<lb/> dens. </s> <s id="s.000883">quod fieri nequit. </s> <s id="s.000884">ergo linea pe minor e&longs;t ip&longs;a g li­<lb/> nea propo&longs;ita.</s> </p> <p type="main"> <s id="s.000885">Ex quibus per&longs;picuum e&longs;t centrum grauitatis <lb/> figuræ in&longs;criptæ, & circum&longs;criptæ eo magis acce<lb/> dere ad portionis centrum, quo pluribus cylin­<lb/> dris, uel cylindri portionibus con&longs;tet: <expan abbr="fiat&qacute;">fiatque</expan>; figu<lb/> ra in&longs;cripta maior, & circum&longs;cripta minor. </s> <s id="s.000886">& <lb/> quanquam continenter ad portionis <expan abbr="centrũ">centrum</expan> pro­<lb/> pius admoueatur: nunquam tamen ad ip&longs;um per <lb/> ueniet. </s> <s id="s.000887">&longs;equeretur enim figuram in&longs;criptam, <expan abbr="nõ">non</expan> <lb/> &longs;olum portioni, &longs;ed etiam circum&longs;criptæ figuræ <lb/> æqualem e&longs;&longs;e. </s> <s id="s.000888">quod e&longs;t ab&longs;urdum.</s> </p> <p type="head"> <s id="s.000889">THEOREMA XXIII. PROPOSITIO XXIX.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000890">CVIVSLIBET portionis conoidis rectangu­<lb/> li axis à <expan abbr="c&etilde;tro">centro</expan> grauitatis ita diuiditur, ut pars quæ <lb/> terminatur ad uerticem, reliquæ partis, quæ ad ba <lb/> &longs;im &longs;it dupla.</s> </p> <p type="main"> <s id="s.000891">SIT portio conoidis rectanguli uel ab&longs;ci&longs;&longs;a plano ad <lb/> axem recto, uel non recto: & &longs;ecta ip&longs;a altero plano per <expan abbr="ax&etilde;">axem</expan><lb/> &longs;it &longs;uperficiei &longs;ectio abc rectanguli coni &longs;ectio, uel parabo <lb/> le; plani ab&longs;cindentis portionem &longs;ectio &longs;it recta linea ac: <lb/> axis portionis, & &longs;ectionis diameter bd. </s> <s id="s.000892">Sumatur autem <lb/> in linea bd punctum e, ita ut be &longs;it ip&longs;ius ed dupla. </s> <s id="s.000893">Dico <pb pagenum="42" xlink:href="023/01/091.jpg"/><figure id="id.023.01.091.1.jpg" xlink:href="023/01/091/1.jpg"/><lb/> e portionis ab <lb/> c grauitatis e&longs;&longs;e <lb/> centrum. </s> <s id="s.000894">Diui­<lb/> datur enim bd <lb/> bifariam in m: <lb/> & rur&longs;us dm, m<lb/> b bifariam diui­<lb/> dantur in pun­<lb/> ctis n, o: <expan abbr="in&longs;cri-baturq;">in&longs;cri­<lb/> baturque</expan> portio­<lb/> ni figura &longs;olida, <lb/> & altera circum <lb/>&longs;cribatur ex cy<lb/> lindris æqualem <lb/> altitudinem ha­<lb/> bentibus, ut &longs;u­<lb/> perius <expan abbr="dictũ">dictum</expan> e&longs;t. </s> <lb/> <s id="s.000895">Sit autem pri­<lb/> mum figura in­<lb/> &longs;cripta <expan abbr="cylĩdrus">cylindrus</expan> <lb/> fg: & <expan abbr="circũ&longs;cri">circum&longs;cri</expan> ­<lb/> pta ex cylindris <lb/> ah, Kl con&longs;tet. </s> <lb/> <s id="s.000896"><arrow.to.target n="marg103"/><lb/> punctum n erit <lb/> centrum graui­<lb/> tatis figuræ in­<lb/> &longs;criptæ, <expan abbr="mediũ">medium</expan> <lb/> &longs;cilicet ip&longs;ius d <lb/> m axis: <expan abbr="atq;">atque</expan> <expan abbr="id&etilde;">idem</expan> <lb/> erit centrum cy<lb/> lindri ah: & cy­<lb/> lindri kl <expan abbr="centrũ">centrum</expan> <lb/> o, axis bm me­<lb/> dium. </s> <s id="s.000897">quare &longs;i li <pb xlink:href="023/01/092.jpg"/><figure id="id.023.01.092.1.jpg" xlink:href="023/01/092/1.jpg"/><lb/> neam on ita di <lb/> ui&longs;erimus in p, <lb/> ut <expan abbr="quã">quam</expan> <expan abbr="propor-tion&etilde;">propor­<lb/> tionem</expan> habet cy­<lb/> lindrus ah ad <lb/> cylindrum kl, <lb/> habeat linea op <lb/> <arrow.to.target n="marg104"/><lb/> ad pn: centrum <lb/> grauitatis toti­<lb/> us figuræ <expan abbr="circũ-&longs;criptæ">circum­<lb/> &longs;criptæ</expan> erit pun<lb/> <arrow.to.target n="marg105"/><lb/> ctum p. </s> <s id="s.000898">Sed cy­<lb/> lindri, qui &longs;unt <lb/> æquali altitudi­<lb/> ne, eandem in­<lb/> ter &longs;e &longs;e, quam <lb/>ba&longs;es propor-<lb/> tionem habent: <lb/> <expan abbr="e&longs;tq;">e&longs;tque</expan> ut linea db <lb/> ad bm, ita <expan abbr="qua-dratũ">qua­<lb/> dratum</expan> lineæ ad <lb/> ad <expan abbr="quadratũ">quadratum</expan> ip­<lb/> &longs;ius Km, ex uige <lb/> &longs;ima primi libri <lb/> <arrow.to.target n="marg106"/><lb/> <expan abbr="conicorũ">conicorum</expan> & ita <lb/> quadratum ac <lb/> ad <expan abbr="quadratũ">quadratum</expan> K <lb/> <arrow.to.target n="marg107"/><lb/> g: hoc e&longs;t circu­<lb/> lus circa diame<lb/> trum ac ad cir­<lb/> culum circa dia<lb/> metrum kg. <!-- KEEP S--></s> <s id="s.000899">du<lb/> pla e&longs;t autem li­<lb/> nea db lineæ <pb pagenum="43" xlink:href="023/01/093.jpg"/>bm. </s> <s id="s.000900">ergo circulus ac circuli kg: & idcirco cylindrus <lb/> ah cylindri k. </s> <s id="s.000901">l duplus erit. </s> <s id="s.000902">quare & linea op dupla <lb/> ip&longs;ius pn. </s> <s id="s.000903">Deinde in&longs;cripta & circum&longs;cripta portioni <lb/> alia figura, ita ut in&longs;cripta con&longs;tituatur ex tribus cylin­<lb/> dris qr, sg, tu: circum&longs;cripta uero ex quatuor ax, yz, <lb/> K<foreign lang="greek">v, ql:</foreign> diuidantur bo, om, mn, nd bifariam in punctis <lb/> <foreign lang="greek">mnpr.</foreign> Itaque cylindri <foreign lang="greek">ql</foreign> centrum grauitatis e&longs;t punctum <lb/> <foreign lang="greek">m:</foreign> & cylindri k<foreign lang="greek">h</foreign> centrum <foreign lang="greek">n.</foreign> ergo &longs;i linea <foreign lang="greek">mg</foreign> diuidatur in <foreign lang="greek">s,</foreign><lb/> ita ut <foreign lang="greek">ms</foreign> ad <foreign lang="greek">sg</foreign> <expan abbr="proportion&etilde;">proportionem</expan> <expan abbr="eã">eam</expan> habeat, quam cylindrus K<foreign lang="greek">h</foreign><lb/> ad cylindrum <foreign lang="greek">ql,</foreign> uidelicet quam quadratum knr ad qua­<lb/> <arrow.to.target n="marg108"/><lb/> dratum <foreign lang="greek">q</foreign>o, hoc e&longs;t, quam linea mb ad bo: erit <foreign lang="greek">s</foreign> centrum <lb/> magnitudinis compo&longs;itæ ex cylindris <foreign lang="greek">kg, ql.</foreign> & cum linea <lb/> mb &longs;it dupla bo, erit & <foreign lang="greek">ms</foreign> ip&longs;ius <foreign lang="greek">sn</foreign> dupla. </s> <s id="s.000904">præterea quo­<lb/> niam cylindri yz centrum grauitatis e&longs;t <foreign lang="greek">p,</foreign> linea <foreign lang="greek">sp</foreign> ita diui<lb/> &longs;a in <foreign lang="greek">t,</foreign> ut <foreign lang="greek">st</foreign> ad <foreign lang="greek">tp</foreign> eam habeat proportionem, quam cylin<lb/> drus yz ad duos cylindros K<foreign lang="greek">n, ql:</foreign> erit <foreign lang="greek">t</foreign> centrum magnitu<lb/> dinis, quæ ex dictis tribus cylindris con&longs;tat. </s> <s id="s.000905">cylindrus <expan abbr="au-t&etilde;">au­<lb/> tem</expan> yz ad cylindrum <foreign lang="greek">ql</foreign> e&longs;t, ut linea nb ad bo, hoc e&longs;t ut 3 <lb/> ad 1: & ad cylindrum k<foreign lang="greek">h</foreign>, ut nb ad bm, uidelicet ut 3 ad 2. <!-- KEEP S--></s> <lb/> <s id="s.000906">quare yz <expan abbr="cylĩdrus">cylindrus</expan> duobus cylindris k<foreign lang="greek">n, ql</foreign> æqualis erit. </s> <s id="s.000907">& <lb/> propterea linea <foreign lang="greek">st</foreign> æqualis ip&longs;i <foreign lang="greek">tp.</foreign> denique cylindri ax <lb/> centrum grauitatis e&longs;t punctum <foreign lang="greek">r.</foreign> & cum <foreign lang="greek">tr</foreign> diui&longs;a fuerit <lb/> in <expan abbr="eã">eam</expan> proportionem, quam habet cylindrus ax ad tres cy­<lb/> lindros yz, k<foreign lang="greek">n, ql:</foreign> erit in eo puncto centrum grauitatis <lb/> totius figuræ <expan abbr="circũ&longs;criptæ">circum&longs;criptæ</expan>. </s> <s id="s.000908">Sed cylindrus ax ad ip&longs;um yz <lb/> e&longs;t ut linea db ad bn: hoc e&longs;t ut 4 ad 3: & duo cylindri k<foreign lang="greek">h<lb/> ql</foreign> cylindro y &longs;unt æquales. </s> <s id="s.000909">cylindrus igitur ax ad tres <lb/> iam dictos cylindros e&longs;t ut 2 ad 3. Sed <expan abbr="quoniã">quoniam</expan> <foreign lang="greek">m s</foreign> e&longs;t dua­<lb/> rum partium, & <foreign lang="greek">s g</foreign> unius, qualium <foreign lang="greek">m p</foreign> e&longs;t &longs;ex; erit <foreign lang="greek">s p</foreign> par­<lb/> tium quatuor: <expan abbr="proptereaq;">proptereaque</expan> <foreign lang="greek">tp</foreign> duarum, & <foreign lang="greek">np,</foreign> hoc e&longs;t <foreign lang="greek">pr</foreign><lb/> trium. </s> <s id="s.000910">quare &longs;equitur ut punctum <foreign lang="greek">p</foreign> totius figuræ circum <lb/> &longs;criptæ &longs;it centrum. </s> <s id="s.000911">Itaque fiat <foreign lang="greek">nu</foreign> ad <foreign lang="greek">up,</foreign> ut <foreign lang="greek">ms</foreign> ad <foreign lang="greek">sg.</foreign> & <foreign lang="greek">ur</foreign><lb/> bifariam diuidatur in <foreign lang="greek">f.</foreign> Similiter ut in circum&longs;cripta figu<lb/> ra o&longs;tendetur centrum magnitudinis compo&longs;itæ ex cylin- <pb xlink:href="023/01/094.jpg"/><figure id="id.023.01.094.1.jpg" xlink:href="023/01/094/1.jpg"/><lb/> dris sg, tu e&longs;&longs;e <lb/> punctum <foreign lang="greek">u:</foreign> & <lb/> totius figuræ in <lb/> &longs;criptæ, quæ <expan abbr="cõ-&longs;tat">con­<lb/> &longs;tat</expan> ex cylindris <lb/> qr, &longs; g, tu e&longs;&longs;e <foreign lang="greek">f</foreign><lb/> centrum. </s> <s id="s.000912">Sunt <lb/> enim hi cylindri <lb/> æquales & &longs;imi­<lb/> les cylindris yz, <lb/> K<foreign lang="greek">h, ql,</foreign> figuræ <lb/> circum&longs;criptæ. </s> <lb/> <s id="s.000913"><expan abbr="Quoniã">Quoniam</expan> igitur <lb/> ut be ad ed, ita <lb/> e&longs;t op ad pn; <lb/> <expan abbr="utraq;">utraque</expan> enim u­<lb/> triu&longs;que e&longs;t du­<lb/> pla: erit compo<lb/> nendo, ut bd ad <lb/> de, ita on ad n <lb/> p; & permutan <lb/> do, ut bd ad o<lb/> n, ita de ad np. </s> <lb/> <s id="s.000914">Sed bd dupla <lb/> e&longs;t on. </s> <s id="s.000915">ergo & <lb/> ed ip&longs;ius np du<lb/> pla erit. </s> <s id="s.000916">quòd &longs;i <lb/> ed bifariam di­<lb/> uidatur <expan abbr="ĩ">im</expan> <foreign lang="greek">x,</foreign> erit <lb/> <foreign lang="greek">x</foreign> d, uel e <foreign lang="greek">x</foreign> æ­<lb/> qualis np: & <lb/> &longs;ublata en, quæ <lb/> e&longs;t <expan abbr="cõmunis">communis</expan> u­<lb/> trique e <foreign lang="greek">x,</foreign> pn, <pb pagenum="44" xlink:href="023/01/095.jpg"/>relinquetur pe ip&longs;i n<foreign lang="greek">x</foreign> æqualis. </s> <s id="s.000917">cum autem be &longs;it dupla <lb/> ed, & op dupla pn, hoc e&longs;t ip&longs;ius e <foreign lang="greek">x,</foreign> & reliquum, uideli­<lb/> <arrow.to.target n="marg109"/><lb/> cet bo unà cum pe ip&longs;ius reliqui <foreign lang="greek">x</foreign> d duplum erit. </s> <s id="s.000918">e&longs;tque <lb/> bo dupla <foreign lang="greek">r</foreign> d. <!-- KEEP S--></s> <s id="s.000919">ergo pe, hoc e&longs;t n<foreign lang="greek">x</foreign> ip&longs;ius <foreign lang="greek">xr</foreign> dupla. </s> <s id="s.000920">&longs;ed dn <lb/> dupla e&longs;t n<foreign lang="greek">r.</foreign> reliqua igitur d<foreign lang="greek">x</foreign> dupla reliquæ <foreign lang="greek">x</foreign> n. </s> <s id="s.000921">&longs;unt au­<lb/> tem d<foreign lang="greek">x,</foreign> pn inter &longs;e æquales: <expan abbr="itemq;">itemque</expan> æquales <foreign lang="greek">x</foreign> n, pe. </s> <s id="s.000922">qua­<lb/> re con&longs;tat np ip&longs;ius pe duplam e&longs;&longs;e. </s> <s id="s.000923">& idcirco pe ip&longs;i en <lb/> æqualem. </s> <s id="s.000924">Rur&longs;us cum &longs;it <foreign lang="greek">mn</foreign> dupla o<foreign lang="greek">n,</foreign> & <foreign lang="greek">m s</foreign> dupla <foreign lang="greek">s g;</foreign> erit <lb/> etiam reliqua <foreign lang="greek">ns</foreign> reliquæ <foreign lang="greek">s</foreign> o dupla. </s> <s id="s.000925">Eadem quoque ratione <lb/> <expan abbr="cõcludetur">concludetur</expan> <foreign lang="greek">p u</foreign> dupla <foreign lang="greek">u</foreign> m. </s> <s id="s.000926">ergo ut <foreign lang="greek">ns</foreign> ad <foreign lang="greek">s</foreign> o, ita <foreign lang="greek">pu</foreign> ad <foreign lang="greek">u</foreign> m: <lb/> <expan abbr="componendoq;">componendoque</expan>, & permutando, ut <foreign lang="greek">n</foreign>o ad <foreign lang="greek">p</foreign>m, ita o<foreign lang="greek">s</foreign> ad <lb/> m<foreign lang="greek">u:</foreign> & &longs;unt æquales <foreign lang="greek">n</foreign>o, <foreign lang="greek">p</foreign>m. </s> <s id="s.000927">quare & o<foreign lang="greek">s,</foreign> m<foreign lang="greek">u</foreign> æquales. </s> <s id="s.000928">præ<lb/> terea <foreign lang="greek">sp</foreign> dupla e&longs;t <foreign lang="greek">pt,</foreign> & <foreign lang="greek">np</foreign> ip&longs;ius <foreign lang="greek">p</foreign>m. </s> <s id="s.000929">reliqua igitur <foreign lang="greek">sn</foreign> re<lb/> liquæ m<foreign lang="greek">t</foreign> dupla. </s> <s id="s.000930">atque erat <foreign lang="greek">ns</foreign> dupla <foreign lang="greek">s</foreign>o. </s> <s id="s.000931">ergo m<foreign lang="greek">t, s</foreign>o æ­<lb/> quales &longs;unt: & ita æquales m<foreign lang="greek">u,</foreign> n<foreign lang="greek">f.</foreign> at o<foreign lang="greek">s,</foreign> e&longs;t æqualis <lb/> m<foreign lang="greek">u.</foreign> Sequitur igitur, ut omnes o<foreign lang="greek">s,</foreign> m<foreign lang="greek">t,</foreign> m<foreign lang="greek">u,</foreign> n<foreign lang="greek">f</foreign> in­<lb/> ter &longs;e &longs;int æquales. </s> <s id="s.000932">Sed ut <foreign lang="greek">rp</foreign> ad <foreign lang="greek">pt,</foreign> hoc e&longs;t ut 3 ad 2, ita nd <lb/> ad d<foreign lang="greek">x:</foreign> <expan abbr="permutãdoq;">permutandoque</expan> ut <foreign lang="greek">rp</foreign> ad nd, ita <foreign lang="greek">pt</foreign> ad d<foreign lang="greek">x.</foreign> & <expan abbr="&longs;ũt">&longs;unt</expan> æqua<lb/> les <foreign lang="greek">rp,</foreign> nd. <!-- KEEP S--></s> <s id="s.000933">ergo d<foreign lang="greek">x,</foreign> hoc e&longs;t np, & <foreign lang="greek">pt</foreign> æquales. </s> <s id="s.000934">Sed etiam æ­<lb/> quales n<foreign lang="greek">p, p</foreign>m. </s> <s id="s.000935">reliqua igitur <foreign lang="greek">p</foreign>p reliquæ m<foreign lang="greek">t,</foreign> hoc e&longs;t ip&longs;i <lb/> n<foreign lang="greek">f</foreign> æqualis erit. </s> <s id="s.000936">quare dempta p<foreign lang="greek">p</foreign> ex pe, & <foreign lang="greek">f</foreign>n dempta ex <lb/> ne, relinquitur pe æqualis e<foreign lang="greek">f.</foreign> Itaque <foreign lang="greek">p, f</foreign> centra <expan abbr="figurarũ">figurarum</expan> <lb/> &longs;ecundo loco de&longs;criptarum a primis centris pn æquali in­<lb/> teruallo recedunt. </s> <s id="s.000937">quòd &longs;i rur&longs;us aliæ figuræ de&longs;cribantur, <lb/> eodem modo demon&longs;trabimus earum centra æqualiter ab <lb/> his recedere, & ad portionis conoidis centrum propius ad <lb/> moueri. </s> <s id="s.000938">Ex quibus con&longs;tat lineam <foreign lang="greek">pf</foreign> à centro grauitatis <lb/> portionis diuidi in partes æquales. </s> <s id="s.000939">Si enim fieri pote&longs;t, non <lb/> &longs;it centrum in puncto e, quod e&longs;t lineæ <foreign lang="greek">pf</foreign> medium: &longs;ed in <lb/> <foreign lang="greek">y:</foreign> & ip&longs;i <foreign lang="greek">py</foreign> æqualis fiat <foreign lang="greek">fw.</foreign> Cum igitur in portione &longs;olida <lb/> quædam figura in&longs;cribi pos&longs;it, ita ut linea, quæ inter cen­<lb/> trum grauitatis portionis, & in&longs;criptæ figuræ interiicitur, <lb/> qualibet linea propo&longs;ita &longs;it minor, quod proxime demon­<lb/> &longs;trauimus: perueniet tandem <foreign lang="greek">f</foreign> centrum in&longs;criptæ figuræ <pb xlink:href="023/01/096.jpg"/><figure id="id.023.01.096.1.jpg" xlink:href="023/01/096/1.jpg"/> <pb pagenum="45" xlink:href="023/01/097.jpg"/>ad punctum <foreign lang="greek">w.</foreign> Sed quoniam <foreign lang="greek">p</foreign> circum&longs;cripta itidem alia <lb/> figura æquali interuallo ad portionis centrum accedit, ubi <lb/> primum <foreign lang="greek">f</foreign> applicuerit &longs;e ad <foreign lang="greek">w,</foreign> & <foreign lang="greek">p</foreign> ad <expan abbr="punctũ">punctum</expan> <foreign lang="greek">y,</foreign> hoc e&longs;t ad <lb/> portionis centrum &longs;e applicabit. </s> <s id="s.000940">quod fieri nullo modo <lb/> po&longs;&longs;e per&longs;picuum e&longs;t. </s> <s id="s.000941">non aliter idem ab&longs;urdum &longs;equetur, <lb/> fi ponamus centrum portionis recedere à medio ad par­<lb/> tes <foreign lang="greek">w;</foreign> e&longs;&longs;et enim aliquando centrum figuræ in&longs;criptæ idem <lb/> quod portionis <expan abbr="centrũ">centrum</expan>. </s> <s id="s.000942">ergo punctum e centrum erit gra<lb/> uitatis portionis abc. quod demon&longs;trare oportebat.</s> </p> <p type="margin"> <s id="s.000943"><margin.target id="marg103"/>7. huius</s> </p> <p type="margin"> <s id="s.000944"><margin.target id="marg104"/>8. primi <lb/> libri Ar­<lb/> chimedis</s> </p> <p type="margin"> <s id="s.000945"><margin.target id="marg105"/>11. duo­<lb/> decimi.</s> </p> <p type="margin"> <s id="s.000946"><margin.target id="marg106"/>15. quinti</s> </p> <p type="margin"> <s id="s.000947"><margin.target id="marg107"/>2. duode­<lb/> cimi</s> </p> <p type="margin"> <s id="s.000948"><margin.target id="marg108"/>20. primi <lb/> <expan abbr="conicorũ">conicorum</expan></s> </p> <p type="margin"> <s id="s.000949"><margin.target id="marg109"/>19.<lb/> quinti</s> </p> <p type="main"> <s id="s.000950">Quod autem &longs;upra <expan abbr="demõ&longs;tratum">demon&longs;tratum</expan> e&longs;t in portione conoi­<lb/> dis recta per figuras, quæ ex cylindris æqualem altitudi­<lb/> dinem habentibus con&longs;tant, idem &longs;imiliter demon&longs;trabi­<lb/> mus per figuras ex cylindri portionibus con&longs;tantes in ea <lb/> portione, quæ plano non ad axem recto ab&longs;cinditur. </s> <s id="s.000951">ut <lb/> enim tradidimus in commentariis in undecimam propo&longs;i<lb/> tionem libri Archimedis de conoidibus & &longs;phæroidibus. </s> <lb/> <s id="s.000952">portiones cylindri, quæ æquali &longs;unt altitudine eam inter &longs;e <lb/> &longs;e proportionem habent, quam ip&longs;arum ba&longs;es: ba&longs;es <expan abbr="aut&etilde;">autem</expan> <lb/> <arrow.to.target n="marg110"/><lb/> quæ &longs;unt ellip&longs;es &longs;imiles eandem proportionem habere, <lb/> quam quadrata diametrorum eiu&longs;dem rationis, ex corol­<lb/> lario &longs;eptimæ propo&longs;itionis libri de conoidibus, & &longs;phæ­<lb/> roidibus, manife&longs;te apparet.</s> </p> <p type="margin"> <s id="s.000953"><margin.target id="marg110"/>corol. 15<lb/> de conoi­<lb/> dibus & <lb/> &longs;phæroi­<lb/> dibus.</s> </p> <p type="head"> <s id="s.000954">THEOREMA XXIIII. PROPOSITIO XXX.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000955">Si à portione conoidis rectanguli alia portio <lb/> ab&longs;cindatur, plano ba&longs;i æquidi&longs;tante; habebit <lb/> portio tota ad eam, quæ ab&longs;ci&longs;&longs;a e&longs;t, duplam pro <lb/> portion em eius, quæ e&longs;t ba&longs;is maioris portionis <lb/> ad ba&longs;i m minoris, uel quæ axis maioris ad axem <lb/> minoris.</s> </p> <pb xlink:href="023/01/098.jpg"/> <p type="main"> <s id="s.000956">ABSCINDATVR à portione conoidis rectanguli <lb/> abc alia portio ebf, plano ba&longs;i æquidi&longs;tante: & eadem <lb/> portio &longs;ecetur alio plano per axem; ut &longs;uperficiei &longs;ectio &longs;it <lb/> parabole abc: <expan abbr="planorũ">planorum</expan> portiones ab&longs;cindentium rectæ <lb/> lincæ ac, ef: axis autem portionis, & &longs;ectionis diameter <lb/> bd; quam linea ef in puncto g &longs;ecet. </s> <s id="s.000957">Dico portionem co­<lb/> noidis abc ad portionem ebf duplam proportionem ha­<lb/> bere eius, quæ e&longs;t ba&longs;is ac ad ba&longs;im ef; uel axis db ad bg<lb/> axem. </s> <s id="s.000958">Intelligantur enim duo coni, &longs;eu coni portiones <lb/> abc, ebf, <expan abbr="eãdem">eandem</expan> ba&longs;im, quam portiones conoidis, & æqua <lb/> lem habentes altitudinem. </s> <s id="s.000959">& quoniam abc portio conoi <lb/> dis &longs;e&longs;quialtera e&longs;t coni, &longs;eu portionis coni abc; & portio <lb/> ebf coni &longs;eu portionis coni bf e&longs;t &longs;e&longs;quialtera, quod de­<lb/> <figure id="id.023.01.098.1.jpg" xlink:href="023/01/098/1.jpg"/><lb/> mon&longs;trauit Archimedes in propo&longs;itionibus 23, & 24 libri <lb/> de conoidibus, & &longs;phæroidibus: erit conoidis portio ad <lb/> conoidis portionem, ut conus ad conum, uel ut coni por­<lb/> tio ad coni portionem. </s> <s id="s.000960">Sed conus, nel coni portio abc ad <lb/> conum, uel coni portionem ebf compo&longs;itam proportio­<lb/> nem habet ex proportione ba&longs;is ac ad ba&longs;im ef, & ex pro­<lb/> portione altitudinis coni, uel coni portionis abc ad alti­<lb/> tudinem ip&longs;ius ebf, ut nos demon&longs;trauimus in commen­<lb/> tariis in undecimam propo&longs;itionem eiu&longs;dem libri Archi­<lb/> medis: altitudo autem ad altitudinem c&longs;t, ut axis ad axem. </s> <lb/> <s id="s.000961">quod quidem in conis rectis per&longs;picuum e&longs;t, in &longs;calenis ue <pb pagenum="46" xlink:href="023/01/099.jpg"/>ro ita demon&longs;trabitur. </s> <s id="s.000962">Ducatur à puncto b ad planum ba­<lb/> &longs;is ac perpendicularis linea bh, quæ ip&longs;am ef in K &longs;ecet. </s> <lb/> <s id="s.000963">erit bh altitudo coni, uel coni portionis abc: & bK altitu<lb/> <arrow.to.target n="marg111"/><lb/> do efg. </s> <s id="s.000964">Quod cum lineæ ac, ef inter &longs;e æquidi&longs;tent, &longs;unt <lb/> enim planorum æquidi&longs;tantium &longs;ectiones: habebit db ad <lb/> <arrow.to.target n="marg112"/><lb/> bg proportionem eandem, quam hb ad bk quare por­<lb/> tio conoidis abc ad portionem efg proportionem habet <lb/> compo&longs;itam ex proportione ba&longs;is ac ad ba&longs;im ef; & ex <lb/> <arrow.to.target n="marg113"/><lb/> proportione db axis ad axem bg. <!-- KEEP S--></s> <s id="s.000965">Sed circulus, uel <lb/> ellip&longs;is circa diametrum ac ad circulum, uel ellip&longs;im <lb/> <arrow.to.target n="marg114"/><lb/> circa ef, e&longs;t ut quadratum ac ad quadratum ef; hoc e&longs;t ut <lb/> <expan abbr="quadratũ">quadratum</expan> ad ad <expan abbr="quadratũ">quadratum</expan> eg. <!-- REMOVE S-->& quadratum ad ad quadra<lb/> tum eg e&longs;t, ut linea db ad lineam bg. <!-- KEEP S--></s> <s id="s.000966">circulus igitur, uel el<lb/> <arrow.to.target n="marg115"/><lb/> lip&longs;is circa diametrum ac ad <expan abbr="circulũ">circulum</expan>, uel ellip&longs;im circa ef, <lb/> <arrow.to.target n="marg116"/><lb/> hoc e&longs;t ba&longs;is ad ba&longs;im eandem proportionem habet, <expan abbr="quã">quam</expan> <lb/> db axis ad axem bg. <!-- KEEP S--></s> <s id="s.000967">ex quibus &longs;equitur portionem abc <lb/> ad portionem ebf habere proportionem duplam eius, <lb/> quæ e&longs;t ba&longs;is ac ad ba&longs;im ef: uel axis db ad bg axem. </s> <s id="s.000968">quod <lb/> demon&longs;trandum proponebatur.</s> </p> <p type="margin"> <s id="s.000969"><margin.target id="marg111"/>16. unde­<lb/> cimi.</s> </p> <p type="margin"> <s id="s.000970"><margin.target id="marg112"/>4 sexti.</s> </p> <p type="margin"> <s id="s.000971"><margin.target id="marg113"/>2. duode<lb/> cimi</s> </p> <p type="margin"> <s id="s.000972"><margin.target id="marg114"/>7. de co­<lb/> noidibus <lb/> & &longs;phæ­<lb/> roidibus</s> </p> <p type="margin"> <s id="s.000973"><margin.target id="marg115"/>15. quinti. </s> <s id="s.000974">quinti</s> </p> <p type="margin"> <s id="s.000975"><margin.target id="marg116"/>20. primi <lb/> <expan abbr="conicorũ">conicorum</expan></s> </p> <p type="head"> <s id="s.000976">THEOREMA XXV. PROPOSITIO XXXI.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000977">Cuiuslibet fru&longs;ti à portione rectanguli conoi<lb/> dis ab&longs;cis&longs;i, centrum grauitatis e&longs;t in axe, ita ut <lb/> demptis primum à quadrato, quod fit ex diame­<lb/> tro maioris ba&longs;is, tertia ip&longs;ius parte, & duabus <lb/> tertiis quadrati, quod fit ex diametro ba&longs;is mino­<lb/> ris: deinde à tertia parte quadrati maioris ba&longs;is <lb/> rur&longs;us dempta portione, ad quam reliquum qua<lb/> drati ba&longs;is maioris unà cum dicta portione <expan abbr="duplã">duplam</expan> <lb/> proportionem habeat eius, quæ e&longs;t quadrati ma­ <pb xlink:href="023/01/100.jpg"/>ioris ba&longs;is ad quadratum minoris: centrum &longs;it in <lb/> eo axis puncto, quo ita diuiditur ut pars, quæ mi<lb/> norem ba&longs;im attingit ad alteram partem eandem <lb/> proportionem habeat, quam dempto quadrato <lb/> minoris ba&longs;is à duabus tertiis quadrati maioris, <lb/> habet id, quod reliquum e&longs;t unà cum portione à <lb/> tertia quadrati maioris parte dempta, ad <expan abbr="reliquã">reliquam</expan> <lb/> eiu&longs;dem tertiæ portionem.</s> </p> <p type="main"> <s id="s.000978">SIT fru&longs;tum à portione rectanguli conoidis ab&longs;ci&longs;&longs;um <lb/> abcd, cuius maior ba&longs;is circulus, uel ellip&longs;is circa diame­<lb/> trum bc, minor circa diametrum ad; & axis ef. </s> <s id="s.000979">de&longs;criba­<lb/> tur autem portio conoidis, à quo illud ab&longs;ci&longs;&longs;um e&longs;t, & pla­<lb/> <figure id="id.023.01.100.1.jpg" xlink:href="023/01/100/1.jpg"/><lb/> no per axem ducto &longs;ecetur; ut &longs;uperficiei &longs;ectio &longs;it parabo­<lb/> le bgc, cuius diameter, & axis portionis gf: deinde gf diui<lb/> datur in puncto h, ita ut gh &longs;it dupla hf: & rur&longs;us ge in ean <lb/> dem proportionem diuidatur: <expan abbr="&longs;itq;">&longs;itque</expan> gk ip&longs;ius ke dupla. </s> <s id="s.000980"><expan abbr="Iã">Iam</expan> <lb/> ex iis, quæ proxime demon&longs;trauimus, con&longs;tat centrum gra<lb/> uitatis portionis bgc e&longs;&longs;e h punctum: & portionis agc <lb/> punctum k. </s> <s id="s.000981">&longs;umpto igitur infra h puncto l, ita ut kh ad hl <pb pagenum="47" xlink:href="023/01/101.jpg"/>eam proportionem habeat, quam abcd fru&longs;tum ad por­<lb/> tionem agd; erit punctum l eius fru&longs;ti grauitatis <expan abbr="c&etilde;trum">centrum</expan>: <lb/> <expan abbr="habebitq;">habebitque</expan> componendo Kl ad lh proportionem eandem, <lb/> <arrow.to.target n="marg117"/><lb/> quam portio conoidis bgc ad agd portionem. </s> <s id="s.000982"><expan abbr="Itaq;">Itaque</expan> quo <lb/> niam quadratum bf ad quadratum ae, hoc e&longs;t quadratum <lb/> bc ad quadratum ad e&longs;t, ut linea fg ad ge: erunt duæ ter­<lb/> tiæ quadrati bc ad duas tertias quadrati ad, ut hg ad gk: <lb/> & &longs;i à duabus tertiis quadrati bc demptæ fuerint duæ ter­<lb/> tiæ quadrati ad: erit <expan abbr="diuid&etilde;do">diuidendo</expan> id, quod relinquitur ad duas <lb/> tertias quadrati ad, ut hk ad kg. <!-- KEEP S--></s> <s id="s.000983">Rur&longs;us duæ tertiæ quadra<lb/> ti ad ad duas tertias quadrati bc &longs;unt, ut kg ad gh: & duæ <lb/> tertiæ quadrati bc ad <expan abbr="tertiã">tertiam</expan> <expan abbr="part&etilde;">partem</expan> ip&longs;ius, ut gh ad hf. </s> <s id="s.000984">ergo <lb/> ex æquali id, quod relinquitur ex duabus tertiis quadrati <lb/> bc, demptis ab ip&longs;is quadrati ad duabus tertiis, ad <expan abbr="tertiã">tertiam</expan> <lb/> partem quadrati bc, ut kh ad hf: & ad portionem <expan abbr="eiu&longs;d&etilde;">eiu&longs;dem</expan> <lb/> tertiæ partis, ad quam unà cum ip&longs;a portione, duplam pro<lb/> portionem habeat eius, quæ e&longs;t quadrati bc ad <expan abbr="quadratũ">quadratum</expan> <lb/> ad, ut Kl ad lh. </s> <s id="s.000985">habet enim Kl ad lh eandem proportio­<lb/> nem, quam conoidis portio bgc ad portionem agd: por­<lb/> tio autem bgc ad portionem agd duplam proportionem <lb/> habet eius, quæ e&longs;t ba&longs;is bc ad ba&longs;im ad: hoc e&longs;t quadrati <lb/> <arrow.to.target n="marg118"/><lb/> bc ad quadratum ad; ut proxime demon&longs;tratum e&longs;t. </s> <s id="s.000986">quare <lb/> dempto ad quadrato à duabus tertiis quadrati bc, erit id, <lb/> quod relinquitur unà cum dicta portione tertiæ partis ad <lb/> reliquam eiu&longs;dem portionem, ut el ad lf. </s> <s id="s.000987">Cum igitur cen­<lb/> trum grauitatis fru&longs;ti abcd &longs;it l, à quo axis ef in eam, <expan abbr="quã">quam</expan> <lb/> diximus, proportionem diuidatur; con&longs;tat <expan abbr="uerũ">uerum</expan> e&longs;&longs;e illud, <lb/> quod demon&longs;trandum propo&longs;uimus.</s> </p> <p type="margin"> <s id="s.000988"><margin.target id="marg117"/>20. 1. coni<lb/> corum.</s> </p> <p type="margin"> <s id="s.000989"><margin.target id="marg118"/>30 huius</s> </p> <p type="head"> <s id="s.000990">FINIS LIBRI DE CENTRO<!-- REMOVE S-->GRAVITATIS SOLIDORVM.<!-- KEEP S--></s> </p> <p type="main"> <s id="s.000991">Impre&longs;&longs;. <!-- REMOVE S-->Bononiæ cum licentia Superiorum, </s> </p> </chap> </body> <back/> </text> </archimedes>