Salusbury, Thomas, Mathematical collections and translations (Tome I), 1667

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      <text>
        <body>
          <chap>
            <pb xlink:href="040/01/173.jpg" pagenum="155"/>
            <p type="margin">
              <s>
                <margin.target id="marg345"/>
                <emph type="italics"/>
              Projects
                <lb/>
              nue their motion
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              by the right line
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              that followeth the
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              direction of the
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              motion, made
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              gether with the
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              projicient, whil'ſt
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              they were conjoin'd
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              therewith.
                <emph.end type="italics"/>
              </s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>So it is, in my opinion.</s>
            </p>
            <p type="main">
              <s>SAGR. </s>
              <s>Now imagine the cylinder to be erected, and that the
                <lb/>
              Earth doth revolve about with a diurnal motion, carrying the
                <lb/>
              piece along with it, tell me what ſhall be the motion of the ball
                <lb/>
              within the cylinder, having given fire?</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>It ſhall be a ſtreight and perpendicular motion, the
                <lb/>
              der being erected perpendicularly.</s>
            </p>
            <p type="main">
              <s>SAGR. </s>
              <s>Conſider well what you ſay: for I believe that it will
                <lb/>
              not be perpendicular. </s>
              <s>It would indeed be perpendicular, if the
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              Earth ſtood ſtill, for ſo the ball would have no other motion but
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              that proceeding from the fire. </s>
              <s>But in caſe the Earth turns round,
                <lb/>
                <arrow.to.target n="marg346"/>
                <lb/>
              the ball that is in the piece, hath likewiſe a diurnal motion, ſo
                <lb/>
              that there being added to the ſame the impulſe of the fire, it
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              veth from the breech of the piece to the muzzle with two motions,
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              from the compoſition whereof it cometh to paſſe that the motion
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              made by the centre of the balls gravity is an inclining line. </s>
              <s>And
                <lb/>
              for your clearer underſtanding the ſame, let the piece A C [
                <emph type="italics"/>
              in
                <lb/>
              Fig.
                <emph.end type="italics"/>
              2.] be erected, and in it the ball B; it is manifeſt, that the
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              piece ſtanding immoveable, and fire being given to it, the ball
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              will make its way out by the mouth A, and with its centre,
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              ſing thorow the the piece, ſhall have deſcribed the perpendicular
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              line B A, and it ſhall purſue that rectitude when it is out of the
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              piece, moving toward the Zenith. </s>
              <s>But in caſe the Earth ſhould
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              move round, and conſequently carry the piece along with it, in
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              the time that the ball driven out of the piece ſhall move along
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              the cylinder, the piece being carried by the Earth, ſhall paſſe
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              to the ſituation D E, and the ball B, in going off, would be at
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              the corniſh D, and the motion of the bals centre, would have
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              been according to the line B D, no longer perpendicular, but
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              clining towards the Eaſt; and the ball (as hath been concluded)
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              being to continue its motion through the air, according to the
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              direction of the motion made in the piece, the ſaid motion ſhall
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              continue on according to the inclination of the line B D, and ſo
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              ſhall no longer be perpendicular, but inclined towards the Eaſt,
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              to which part the piece doth alſo move; whereupon the ball may
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              follow the motion of the Eerth, and of the piece. </s>
              <s>Now
                <emph type="italics"/>
              Simplicius,
                <emph.end type="italics"/>
                <lb/>
              you ſee it demonſtrated, that the Range which you took to be
                <lb/>
              perpendicular, is not ſo.</s>
            </p>
            <p type="margin">
              <s>
                <margin.target id="marg346"/>
                <emph type="italics"/>
              The revolution
                <lb/>
              of the Earth
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              poſed, the ball in
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              the piece erected
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              perpendicularly,
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              doth not move by a
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              perpendicular, but
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              an inclined line.
                <emph.end type="italics"/>
              </s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>I do not very well underſtand this buſineſs; do you,
                <lb/>
                <emph type="italics"/>
              Salviatus
                <emph.end type="italics"/>
              ?</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>I apprehend it in part; but I have a certain kind of
                <lb/>
              ſcruple, which I wiſh I knew how to expreſs. </s>
              <s>It ſeems to me, that
                <lb/>
              according to what hath been ſaid, if the Piece be erected
                <lb/>
              dicular, and the Earth do move, the ball would not be to fall, as
                <lb/>
                <emph type="italics"/>
              Ariſtotle
                <emph.end type="italics"/>
              and
                <emph type="italics"/>
              Tycho
                <emph.end type="italics"/>
              will have it, far from the Piece towards the </s>
            </p>
          </chap>
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