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

List of thumbnails

< >
161
161 		162
162
163
163 		164
164
165
165 		166
166
167
167 		168
168
169
169 		170
170
< >
page |< < of 701 > >|
    <archimedes>
      <text>
        <body>
          <chap>
            <p type="main">
              <s>
                <pb xlink:href="040/01/168.jpg" pagenum="150"/>
              part but with two onely: but if the ſame bow be uſed, it always
                <lb/>
              receiveth thence three degrees.</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>It doth ſo; and for this reaſon, ſhooting with the
                <lb/>
              ſame bow in the chariots courſe, the ſhoots cannot be equal.</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>I had forgot to ask, with what velocity it is ſuppoſed in
                <lb/>
              this particular experiment, that the chariot runneth.</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>The velocity of the chariot muſt be ſuppoſed to be one
                <lb/>
              degree in compariſon to that of the bow, which is three,</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>Very right, for ſo computation gives it. </s>
              <s>But tell me,
                <lb/>
              when the chariot moveth, doth not all things in the ſame move
                <lb/>
              with the ſame velocity?</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>Yes doubtleſs.</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>Then ſo doth the ſhaft alſo, and the bow, and the ſtring,
                <lb/>
              upon which the ſhaft is nock't.</s>
            </p>
            <p type="main">
              <s>SIMP. </s>
              <s>They do ſo.</s>
            </p>
            <p type="main">
              <s>SALV. </s>
              <s>Why then, in diſcharging the ſhaft towards the courſe
                <lb/>
              of the chariot, the bow impreſſeth its three degrees of velocity on
                <lb/>
              a ſhaft that had one degree of velocity before, by means of the
                <lb/>
              chariot which tranſported it ſo faſt towards that part; ſo that in
                <lb/>
              its going off it hath four degrees of velocity. </s>
              <s>On the contrary,
                <lb/>
              in the other ſhoot, the ſame bow conferreth its ſame three degrees
                <lb/>
              of velocity on a ſhaft that moveth the contrary way, with one
                <lb/>
              gree; ſo that in its departing from the bow-ſtring, it hath no more
                <lb/>
              left but onely two degrees of velocity. </s>
              <s>But you your ſelf have
                <lb/>
              already ſaid, that the way to make the ſhoots equal, is to cauſe
                <lb/>
              that the ſhaft be let flie the firſt time with four degrees of velocity,
                <lb/>
              and the ſecond time with two. </s>
              <s>Therefore without changing the
                <lb/>
              bow, the very courſe of the chariot is that which adjuſteth the
                <lb/>
                <arrow.to.target n="marg338"/>
                <lb/>
              flights, and the experiment doth ſo repreſent them to any one who
                <lb/>
              is not either wilfully or naturally incapable of reaſon. </s>
              <s>Now
                <lb/>
              apply this diſcourſe to Gunnery, and you ſhall find, that whether the
                <lb/>
              Earth move or ſtand ſtill, the ſhots made with the ſame force, will
                <lb/>
              always curry equal ranges, to what part ſoever aimed. </s>
              <s>The error
                <lb/>
              of
                <emph type="italics"/>
              Ariſtotle, Ptolomey, Iycho,
                <emph.end type="italics"/>
              your ſelf, and all the reſt, is
                <lb/>
              ed upon that fixed and ſtrong perſuaſion, that the Earth ſtandeth
                <lb/>
              ſtill, which you have not judgment nor power to depoſe, no not
                <lb/>
              when you have a deſire to argue of that which would enſue,
                <lb/>
              ſuppoſing the Earth to move. </s>
              <s>And thus, in the other argument,
                <lb/>
              not conſidering that whil'ſt the ſtone is upon the Tower, it doth,
                <lb/>
              as to moving or not moving, the ſame that the Terreſtrial Globe
                <lb/>
              doth, becauſe you have concluded with your ſelf, that the Earth
                <lb/>
              ſtands ſtill, you always diſcourſe touching the fall of the ſtone, as
                <lb/>
              if it were to depart from reſt: whereas it behooveth to ſay, that
                <lb/>
              if the Earth ſtandeth ſtill, the ſtone departeth from reſt, and
                <lb/>
              ſcendeth perpendicularly; but if the Earth do move, the ſtone </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>
Impressum