Gravesande, Willem Jacob 's, An essay on perspective

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        <div xml:id="echoid-div301" type="section" level="1" n="162">
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              <pb o="82" file="0144" n="166" rhead="An ESSAY"/>
            ſection with F a, will determine a X the Repre-
              <lb/>
            ſentation ſought.</s>
            <s xml:id="echoid-s1911" xml:space="preserve"/>
          </p>
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        <div xml:id="echoid-div303" type="section" level="1" n="163">
          <head xml:id="echoid-head169" xml:space="preserve">
            <emph style="sc">Remarks</emph>
          .</head>
          <p>
            <s xml:id="echoid-s1912" xml:space="preserve">Although we ſuppoſe the Eye in all the
              <lb/>
            Problems in this Chapter to be above the per-
              <lb/>
            ſpective Plane, yet it may likewiſe be under
              <lb/>
            the ſaid Plane; </s>
            <s xml:id="echoid-s1913" xml:space="preserve">in which Cafe, the Geometrical
              <lb/>
            Plane is ſuppoſed above the Objects, as we have
              <lb/>
            already done on another Occaſion.</s>
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          <note symbol="*" position="left" xml:space="preserve">79.</note>
        </div>
        <div xml:id="echoid-div304" type="section" level="1" n="164">
          <head xml:id="echoid-head170" xml:space="preserve">CHAP. VII.</head>
          <head xml:id="echoid-head171" style="it" xml:space="preserve">Of Shadows.</head>
          <p>
            <s xml:id="echoid-s1915" xml:space="preserve">FIRST we muſt obſerve, with thoſe who
              <lb/>
            have already treated on this Subject, that
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            when a luminous Body is equal to an opaque
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            Body it enlightens, the Shadow of the ſaid Body
              <lb/>
            is contain’d between parallel Lines, and con-
              <lb/>
            ſequently, it is equal upon all parallel Lines
              <lb/>
            placed at any Diſtance whatſoever beyond the
              <lb/>
            opaque Body. </s>
            <s xml:id="echoid-s1916" xml:space="preserve">And when the luminous Body
              <lb/>
            is leſſer than the opaque Body, the Shadow
              <lb/>
            thereof, increaſes, and is infinitely augmented.
              <lb/>
            </s>
            <s xml:id="echoid-s1917" xml:space="preserve">And on the contrary, when an opaque Body
              <lb/>
            is leſs than the luminous Body, the Shadow there-
              <lb/>
            of decreaſes and terminates in a Point.</s>
            <s xml:id="echoid-s1918" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1919" xml:space="preserve">Now becauſe the Sun is vaſtly greater than
              <lb/>
            any of the Bodies on the Earth’s Surface it en-
              <lb/>
            lightens, and is at ſo great a Diſtance therefrom,
              <lb/>
            therefore its Rays may be conſider’d as being
              <lb/>
            parallel; </s>
            <s xml:id="echoid-s1920" xml:space="preserve">and conſequently, the Bodies it ſhines
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            upon as encloſed between parallels: </s>
            <s xml:id="echoid-s1921" xml:space="preserve">And this
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            is the firſt Kind of Shadows I ſhall here explain;</s>
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