Gravesande, Willem Jacob 's, An essay on perspective

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        <div xml:id="echoid-div96" type="section" level="1" n="54">
          <p>
            <s xml:id="echoid-s732" xml:space="preserve">
              <pb o="27" file="0055" n="60" rhead="on PERSPECTIVE."/>
            actly determined, this Method ought not then to
              <lb/>
            be uſed.</s>
            <s xml:id="echoid-s733" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div98" type="section" level="1" n="55">
          <head xml:id="echoid-head57" xml:space="preserve">
            <emph style="sc">Problem</emph>
          III.</head>
          <p style="it">
            <s xml:id="echoid-s734" xml:space="preserve">44. </s>
            <s xml:id="echoid-s735" xml:space="preserve">To find the Appearance of the Diviſions of a
              <lb/>
            Line in the Geometrical Plane.</s>
            <s xml:id="echoid-s736" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s737" xml:space="preserve">Let A B be a Line, whoſe Appearance is ab.
              <lb/>
            </s>
            <s xml:id="echoid-s738" xml:space="preserve">
              <note position="right" xlink:label="note-0055-01" xlink:href="note-0055-01a" xml:space="preserve">Fig. 14.</note>
            Now to find the Repreſentation of the Diviſions
              <lb/>
            of this Line, there muſt be Lines drawn from
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            the Diviſions of the Line to the Eye, whoſe
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            Interſections with a b will give the Points
              <lb/>
            ſought.</s>
            <s xml:id="echoid-s739" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s740" xml:space="preserve">Note, When theſe Lines very obliquely cut
              <lb/>
            a b, the following Way ought to uſed.</s>
            <s xml:id="echoid-s741" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div100" type="section" level="1" n="56">
          <head xml:id="echoid-head58" xml:space="preserve">
            <emph style="sc">Method</emph>
          . II.</head>
          <p>
            <s xml:id="echoid-s742" xml:space="preserve">45. </s>
            <s xml:id="echoid-s743" xml:space="preserve">To find the Repreſentations of the Di-
              <lb/>
            viſions of the Line G C, make choice of the
              <lb/>
              <note position="right" xlink:label="note-0055-02" xlink:href="note-0055-02a" xml:space="preserve">Fig. 14.</note>
            Point D at Pleaſure without this Line, and find
              <lb/>
            the Repreſentation d thereof; </s>
            <s xml:id="echoid-s744" xml:space="preserve">then draw
              <note symbol="*" position="right" xlink:label="note-0055-03" xlink:href="note-0055-03a" xml:space="preserve">21.</note>
            through the propoſed Diviſions to the Point D;
              <lb/>
            </s>
            <s xml:id="echoid-s745" xml:space="preserve">and from the Points wherein theſe Lines con-
              <lb/>
            tinued out cut the Baſe Line, draw other Lines
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            through the Repreſentation d, which will cut c g
              <lb/>
            the Repreſentation of C G in the Points ſought.</s>
            <s xml:id="echoid-s746" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div102" type="section" level="1" n="57">
          <head xml:id="echoid-head59" xml:space="preserve">
            <emph style="sc">Problem</emph>
          IV.</head>
          <p style="it">
            <s xml:id="echoid-s747" xml:space="preserve">46. </s>
            <s xml:id="echoid-s748" xml:space="preserve">To throw a Polygon, or any other regular
              <lb/>
            Figure on the Geometrical Plane into Perſpective.</s>
            <s xml:id="echoid-s749" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s750" xml:space="preserve">The Repreſentation of any Kinds of Figures
              <lb/>
            may be found by any one of the Methods
              <note symbol="*" position="right" xlink:label="note-0055-04" xlink:href="note-0055-04a" xml:space="preserve">21.</note>
            Problem I. </s>
            <s xml:id="echoid-s751" xml:space="preserve">the fourth in general is the eaſieſt;
              <lb/>
            </s>
            <s xml:id="echoid-s752" xml:space="preserve">and may be firſt uſed in finding the
              <note symbol="*" position="right" xlink:label="note-0055-05" xlink:href="note-0055-05a" xml:space="preserve">22.</note>
            ſentations of Points, or ſometimes of one
              <lb/>
            only; </s>
            <s xml:id="echoid-s753" xml:space="preserve">and then the fifth Method ſerves
              <note symbol="*" position="right" xlink:label="note-0055-06" xlink:href="note-0055-06a" xml:space="preserve">31.</note>
            </s>
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