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

Table of figures

< >
[Figure 151]
[Figure 152]
[Figure 153]
[Figure 154]
[Figure 155]
[Figure 156]
[Figure 157]
[Figure 158]
[Figure 159]
[Figure 160]
[Figure 161]
[Figure 162]
[Figure 163]
[Figure 164]
[Figure 165]
[Figure 166]
[Figure 167]
[Figure 168]
[Figure 169]
[Figure 170]
[Figure 171]
[Figure 172]
[Figure 173]
[Figure 174]
[Figure 175]
[Figure 176]
[Figure 177]
[Figure 178]
[Figure 179]
[Figure 180]
< >
page |< < of 701 > >|
    <archimedes>
      <text>
        <body>
          <chap>
            <pb xlink:href="040/01/938.jpg" pagenum="245"/>
            <p type="main">
              <s>SAGR. </s>
              <s>You argue very well, and make no ſeruple at all of
                <lb/>
              granting, that be the Force of the Mover never ſo ſmall it ſhall ſu­
                <lb/>
              perate any what ever great Reſiſtance at all times when that ſhall
                <lb/>
              more exceed in Velocity than this doth in Force and Gravity.
                <lb/>
              </s>
              <s>Now come we to the caſe of the Rope. </s>
              <s>And drawing a ſmall
                <lb/>
              Scheme be pleaſed to underſtand for once that this Line A B, reſt­
                <lb/>
              ing upon the two fixed and ſtanding points A and B, to have hang­
                <lb/>
              ing at its ends, as you ſee, two immenſe Weights C and D, which
                <lb/>
              drawing it with great Force make it to ſtand directly diſtended, it
                <lb/>
              being a ſimple Line without any gravity. </s>
              <s>And here I proceed, and
                <lb/>
              tell you, that if at the midſt of that which is the point E, you ſhould
                <lb/>
              hang any never ſo little a Weight, as is this H, the Line A B would
                <lb/>
              yield, and inclining towards the point F, and by conſequence
                <lb/>
              lengthening, will conſtrain the two great Weights C and D to
                <lb/>
              aſcend upwards: which I demonſtrate to you in this manner:
                <lb/>
              About the two points A and B as Centers I deſcribe two Quadrants
                <lb/>
              E F G, and E L M, and in regard that the two Semidiameters AI
                <lb/>
              and B L are equal to the two Semidiameters A E and E B, the exceſ­
                <lb/>
              ſes F I and F L ſhall be the quantity of the prolongations of the
                <lb/>
              parts A F and F B, above A E and E B; and of conſequence ſhall
                <lb/>
                <figure id="id.040.01.938.1.jpg" xlink:href="040/01/938/1.jpg" number="164"/>
                <lb/>
              determine the Aſcents
                <lb/>
              of the Weights C and
                <lb/>
              D, in caſe that the
                <lb/>
              Weight H had had a
                <lb/>
              power to deſcend to F:
                <lb/>
              which might then be
                <lb/>
              in caſe the Line E F,
                <lb/>
              which is the quantity
                <lb/>
              of the Deſcent of the
                <lb/>
              ſaid Weight H, had
                <lb/>
              greater proportion to
                <lb/>
              the Line F I which de­
                <lb/>
              termineth the Aſcent of
                <lb/>
              the two Weights C &
                <lb/>
              D, than the pondero­
                <lb/>
              ſity of both thoſe Weights hath to the ponderoſity of the Weight
                <lb/>
              H. </s>
              <s>But this will neceſſarily happen, be the ponderoſity of the
                <lb/>
              Weights C and D never ſo great, and that of H never ſo ſmall; for
                <lb/>
              the exceſs of the Weights C and D above the Weight His not ſo
                <lb/>
              great, but that the exceſs of the Tangent E F above the part of the
                <lb/>
              Secant F I may bear a greater proportion. </s>
              <s>Which we will prove
                <lb/>
              thus: Let there be a Circle whoſe Diameter is G A I; and look
                <lb/>
              what proportion the ponderoſity of the Weights C and D have to
                <lb/>
              the ponderoſity of H, let the Line B O have the ſame proportion to
                <lb/>
              another, which let be C, than which let D be leſſer: So that B O </s>
            </p>
          </chap>
        </body>
      </text>
    </archimedes>