Gravesande, Willem Jacob 's, An essay on perspective

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        <div xml:id="echoid-div203" type="section" level="1" n="107">
          <p>
            <s xml:id="echoid-s1397" xml:space="preserve">
              <pb o="58" file="0106" n="121" rhead="An ESSAY"/>
            their accidental Point F, afterwards find the Re-
              <lb/>
            preſentation of their Baſes: </s>
            <s xml:id="echoid-s1398" xml:space="preserve">This being done,
              <lb/>
            denote the Appearances of the Lines wherein
              <lb/>
            the Shores meet the Wall, upon the Perſpective
              <lb/>
            of the Wall; </s>
            <s xml:id="echoid-s1399" xml:space="preserve">the Appearances here are the
              <lb/>
            Lines p t, r s, which repreſent Lines parallel to
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            the Geometrical Plane, from the Suppoſition,
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            that the Shores are parallel between themſelves,
              <lb/>
            and their Baſes equally diſtant from the Wall.
              <lb/>
            </s>
            <s xml:id="echoid-s1400" xml:space="preserve">Finally, draw Lines from the Angles of the Re-
              <lb/>
            preſentations 1 2 3 4, to the Point F, which
              <lb/>
            will be terminated by their Interſections with
              <lb/>
            p t and r s, and will give the Appearances ſought,
              <lb/>
            as you ſee in the Figure.</s>
            <s xml:id="echoid-s1401" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div205" type="section" level="1" n="108">
          <head xml:id="echoid-head114" xml:space="preserve">
            <emph style="sc">Example</emph>
          II.</head>
          <p style="it">
            <s xml:id="echoid-s1402" xml:space="preserve">To throw ſeveral parallel Roofs of a Houſe into
              <lb/>
            Perſpective.</s>
            <s xml:id="echoid-s1403" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1404" xml:space="preserve">Having found the accidental Points G and Q
              <lb/>
              <note position="left" xlink:label="note-0106-01" xlink:href="note-0106-01a" xml:space="preserve">Fig. 39.</note>
            of the ſaid Roofs, in the Repreſentation of
              <lb/>
            the Wall ſuſtaining them, denote the Points
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            a b c d, wherein the ſaid Roofs meet the Wall:
              <lb/>
            </s>
            <s xml:id="echoid-s1405" xml:space="preserve">Then from the Point G draw Lines through the
              <lb/>
            Points a b c; </s>
            <s xml:id="echoid-s1406" xml:space="preserve">and from the Point Q others to
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            the Points b c d; </s>
            <s xml:id="echoid-s1407" xml:space="preserve">theſe Lines by their mutual
              <lb/>
            Interſection will determine each other, and give
              <lb/>
            the Repreſentations ſought.</s>
            <s xml:id="echoid-s1408" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div207" type="section" level="1" n="109">
          <head xml:id="echoid-head115" xml:space="preserve">
            <emph style="sc">Conclusion</emph>
          .</head>
          <p>
            <s xml:id="echoid-s1409" xml:space="preserve">74. </s>
            <s xml:id="echoid-s1410" xml:space="preserve">From what has been already ſaid, it will
              <lb/>
            not be difficult to throw any Objects whatſoever
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            into Perſpective. </s>
            <s xml:id="echoid-s1411" xml:space="preserve">But ſince it is very difficult,
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            and indeed impoſſible for a Painter to make a
              <lb/>
            Deſign entirely according to the Rules we have
              <lb/>
            preſcribed; </s>
            <s xml:id="echoid-s1412" xml:space="preserve">the Number of Points to be found
              <lb/>
            being almoſt infinite: </s>
            <s xml:id="echoid-s1413" xml:space="preserve">therefore the </s>
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