Archimedes, Archimedis De iis qvae vehvntvr in aqva libri dvo
page |< < (30) of 213 > >|
    <echo version="1.0RC">
      <text xml:lang="la" type="free">
        <div xml:id="echoid-div254" type="section" level="1" n="87">
          <p>
            <s xml:id="echoid-s4278" xml:space="preserve">
              <pb o="30" file="0171" n="171" rhead="DE CENTRO GRAVIT. SOLID."/>
            pra demonſtratum eſt, ita eſſe cylindrum, uel cylindri por-
              <lb/>
              <note position="right" xlink:label="note-0171-01" xlink:href="note-0171-01a" xml:space="preserve">8. huius</note>
            tionem ad priſina, cuius baſis rectilinea figura, & </s>
            <s xml:id="echoid-s4279" xml:space="preserve">æqua-
              <lb/>
            lis altitudo. </s>
            <s xml:id="echoid-s4280" xml:space="preserve">ergo per conuerſionem rationis, ut circulus,
              <lb/>
            uel ellipſis ad portiones, ita conus, uel coni portio ad por-
              <lb/>
            tiones ſolidas. </s>
            <s xml:id="echoid-s4281" xml:space="preserve">quare conus uel coni portio ad portiones
              <lb/>
            ſolidas maiorem habet proportionem, quam g e ad e f: </s>
            <s xml:id="echoid-s4282" xml:space="preserve">& </s>
            <s xml:id="echoid-s4283" xml:space="preserve">
              <lb/>
            diuidendo, pyramis ad portiones ſolidas maiorem pro-
              <lb/>
            portionem habet, quam g f ad f e. </s>
            <s xml:id="echoid-s4284" xml:space="preserve">ſiat igitur q f ad f e
              <lb/>
            ut pyramis ad dictas portiones. </s>
            <s xml:id="echoid-s4285" xml:space="preserve">Itaque quoniam à cono
              <lb/>
            uel coni portione, cuius grauitatis centrum eſt f, aufer-
              <lb/>
            tur pyramis, cuius centrum e; </s>
            <s xml:id="echoid-s4286" xml:space="preserve">reliquæ magnitudinis,
              <lb/>
            quæ ex ſolidis portionibus conſtat, centrum grauitatis
              <lb/>
            erit in linea e f protracta, & </s>
            <s xml:id="echoid-s4287" xml:space="preserve">in puncto q. </s>
            <s xml:id="echoid-s4288" xml:space="preserve">quod fieri
              <lb/>
            non poteft: </s>
            <s xml:id="echoid-s4289" xml:space="preserve">eſt enim centrum grauitatis intra. </s>
            <s xml:id="echoid-s4290" xml:space="preserve">Conſtat
              <lb/>
            igitur coni, uel coni portionis grauitatis centrum eſſe pun
              <lb/>
            ctum e. </s>
            <s xml:id="echoid-s4291" xml:space="preserve">quæ omnia demonſtrare oportebat.</s>
            <s xml:id="echoid-s4292" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div258" type="section" level="1" n="88">
          <head xml:id="echoid-head95" xml:space="preserve">THEOREMA XIX. PROPOSITIO XXIII.</head>
          <p>
            <s xml:id="echoid-s4293" xml:space="preserve">
              <emph style="sc">Qvodlibet</emph>
            fruſtum à pyramide, quæ
              <lb/>
            triangularem baſim habeat, abſciſſum, diuiditur
              <lb/>
            in tres pyramides proportionales, in ea proportio
              <lb/>
            ne, quæ eſt lateris maioris baſis ad latus minoris
              <lb/>
            ipſi reſpondens.</s>
            <s xml:id="echoid-s4294" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s4295" xml:space="preserve">Hoc demonſtrauit Leonardus Piſanus in libro, qui de-
              <lb/>
            praxi geometriæ inſcribitur. </s>
            <s xml:id="echoid-s4296" xml:space="preserve">Sed quoniam is adhucim-
              <lb/>
            preſſus non eſt, nos ipſius demonſtrationem breuíter
              <lb/>
            perſtringemus, rem ipſam ſecuti, non uerba. </s>
            <s xml:id="echoid-s4297" xml:space="preserve">Sit fru-
              <lb/>
            ſtum pyramidis a b c d e f, cuíus maior baſis triangulum
              <lb/>
            a b c, minor d e f: </s>
            <s xml:id="echoid-s4298" xml:space="preserve">& </s>
            <s xml:id="echoid-s4299" xml:space="preserve">iunctis a e, e c, c d, per line-
              <lb/>
            as a e, e c ducatur planum ſecans fruſtum: </s>
            <s xml:id="echoid-s4300" xml:space="preserve">itemque per
              <lb/>
            lineas e c, c d; </s>
            <s xml:id="echoid-s4301" xml:space="preserve">& </s>
            <s xml:id="echoid-s4302" xml:space="preserve">per c d, d a alia plana ducantur, quæ,
              <lb/>
            diuident fruſtum in tres pyramides a b c e, a d c e, d e f c.</s>
            <s xml:id="echoid-s4303" xml:space="preserve"/>
          </p>
        </div>
      </text>
    </echo>