Galilei, Galileo, The systems of the world, 1661

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    <archimedes>
      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb xlink:href="065/01/025.jpg" pagenum="19"/>
              ſame, not to ſerve for a neceſſary demonſtration, but to adorn a
                <lb/>
                <emph type="italics"/>
              Platonick
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              Conceit; to which I will add another particular
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              vation of our
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              Academick,
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              which hath in it ſomething of
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              ble. </s>
              <s>Let us ſuppoſe amongſt the decrees of the divine
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              Architect,
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                <lb/>
              a purpoſe of creating in the World theſe Globes, which we
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              hold continually moving round, and of aſſigning the centre of
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              their converſions; and that in it he had placed the Sun immoveable,
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              and had afterwards made all the ſaid Globes in the ſame place,
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              and with the intended inclinations of moving towards the Centre,
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              till they had acquired thoſe degrees of velocity, which at firſt
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              med good to the ſame Divine Minde; the which being acquired,
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              we laſtly ſuppoſe that they were turned round, each in his Sphere
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              retaining the ſaid acquired velocity: it is now demanded, in
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              what altitude and diſtance from the Sun the place was where the
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              ſaid Orbs were primarily created; and whether it be poſſible that
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              they might all be created in the ſame place? </s>
              <s>To make this
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              ſtigation, we muſt take from the moſt skilfull Aſtronomers the
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              magnitude of the Spheres in which the Planets revolve, and
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              wiſe the time of their revolutions: from which two cognitions is
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              gathered how much (for example)
                <emph type="italics"/>
              Jupiter
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              is ſwifter than
                <emph type="italics"/>
                <lb/>
              turne
                <emph.end type="italics"/>
              ; and being found (as indeed it is) that
                <emph type="italics"/>
              Jupiter
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              moves more
                <lb/>
              ſwiftly, it is requiſite, that departing from the ſame altitude,
                <emph type="italics"/>
                <lb/>
              piter
                <emph.end type="italics"/>
              be deſcended more than
                <emph type="italics"/>
              Saturne,
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              as we really know it is, its
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              Orbe being inferiour to that of
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              Saturne.
                <emph.end type="italics"/>
              But by proceeding
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              wards, from the proportions of the two velocities of
                <emph type="italics"/>
              Jupiter
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              and
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                <emph type="italics"/>
              Saturne,
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              and from the diſtance between their Orbs, and from the
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              proportion of acceleration of natural motion, one may finde in
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              what altitude and diſtance from the centre of their revolutions,
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                <arrow.to.target n="marg49"/>
                <lb/>
              was the place from whence they firſt departed. </s>
              <s>This found out,
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              and agreed upon, it is to be ſought, whether
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              Mars
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              deſcending
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              from thence to his Orb, the magnitude of the Orb, and the
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              locity of the motion, agree with that which is found by
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              tion; and let the like be done of the
                <emph type="italics"/>
              Eartb,
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              of
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              Venus,
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              and of
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                <emph type="italics"/>
              Mercury
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              ; the greatneſs of which Spheres, and the velocity of
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              their motions, agree ſo nearly to what computation gives, that it
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              is very admirable.</s>
            </p>
            <p type="margin">
              <s>
                <margin.target id="marg48"/>
                <emph type="italics"/>
              The circular
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              tion is never
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              quired naturally,
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              without right
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              tion precede it.
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              </s>
              <s>Circular motion
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              perpetually
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              form.
                <emph.end type="italics"/>
              </s>
            </p>
            <p type="margin">
              <s>
                <margin.target id="marg49"/>
                <emph type="italics"/>
              The magnitude of
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              the Orbs, and the
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              velocity of the
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              tion of the Planets,
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              anſwer
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              ably, as if
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              ed from the ſame
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              place.
                <emph.end type="italics"/>
              </s>
            </p>
            <p type="main">
              <s>SAGR. </s>
              <s>I have hearkened to this conceit with extreme delight;
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              and, but that I believe the making of theſe calculations truly
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              would be a long and painfull task, and perhaps too hard for me
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              to comprehend, I would make a trial of them.</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>The operation indeed is long and difficult; nor could
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              I be certain to finde it ſo readily; therefore we ſhall refer it to
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              other time, and for the preſent we will return to our firſt
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              ſal, going on there where we made digreſſion; which, if I well
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              remember, was about the proving the motion by a right line of no </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
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