Gravesande, Willem Jacob 's, An essay on perspective

Table of figures

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[31] page 48.Plate 13.Fig. 32.V S R L P B D Q T M I F A E Y C G O H Z N
[32] page 52.Plate. 14.Fig. 34D C F G A B H L E
[33] Fig. 33S X 8 1 h 6 g 3 z q 9 m 2 4 m a 5 Y
[34] Fig. 35O M D P T Q R m p q B A S C
[35] page 56.Plate. 15F H O Z D G
[36] Fig. 36T N M L a R Q E I A C P B
[37] Fig. 37F S V T I E M A N X P C B
[38] page 58.Plate. 16Fig. 39Fig. 38F Q O p l r s 1 2 3 4 G
[39] page 60.Plate. 17F V
[40] Fig. 40c θ b e a F G H I K L A B E C D
[41] page 64Plate. 18.d v
[42] Fig. 41E b a G F H C B A D
[43] Fig. 42G Q A M I S E H T B L Z F P a X Y N C D R O
[44] page 68Plate. 19Fig. 43B D E a G H I C F L
[45] Fig. 44O V X S H I T
[46] Fig. 45Q F V X S a H B C D E L M P T A
[47] page 72Plate. 20Fig. 46V I X a E M P A T
[48] Fig. 47V F X a Q G H D N A T R
[49] Page 34.Plate. 21Fig. 48F O D X S b a G N A E T B P C
[50] Fig. 49H F O D G X a M N L R Q
[51] Page 36Plate 22Fig. 50O R E G N S M
[52] Fig. 51I H T a X
[53] Fig. 52C D X I H G a F E L b T
[54] Fig. 53H I F T x d X L B C
[55] page 64.Plate 23.Fig. 54O M P Q t A X x Q R N
[56] Fig. 55G F b T L a
[57] Fig. 56I F a X b E T C P
[58] page 66.Plate. 24.Fig. 57E A Z C P B
[59] Fig. 58F O D I a b
[60] Fig. 59F E Z C A B
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        <div xml:id="echoid-div200" type="section" level="1" n="105">
          <pb o="57" file="0105" n="120" rhead="on PERSPECTIVE."/>
          <p>
            <s xml:id="echoid-s1370" xml:space="preserve">The Operation of Prob. </s>
            <s xml:id="echoid-s1371" xml:space="preserve">VII. </s>
            <s xml:id="echoid-s1372" xml:space="preserve">muſt be uſed
              <lb/>
            here, but with this Difference (ſee Fig. </s>
            <s xml:id="echoid-s1373" xml:space="preserve">of the
              <lb/>
            ſaid Prob.) </s>
            <s xml:id="echoid-s1374" xml:space="preserve">that whereas a I in the ſaid Problem
              <lb/>
            is perpendicular to the Baſe Line, here it muſt
              <lb/>
            make an Angle with the Baſe Line, equal to the
              <lb/>
            Angle of Inclination of the given Lines.</s>
            <s xml:id="echoid-s1375" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1376" xml:space="preserve">For the Demonſtration of this, ſee n. </s>
            <s xml:id="echoid-s1377" xml:space="preserve">7, and 10.</s>
            <s xml:id="echoid-s1378" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div201" type="section" level="1" n="106">
          <head xml:id="echoid-head112" xml:space="preserve">
            <emph style="sc">Prob</emph>
          . XIV.</head>
          <p style="it">
            <s xml:id="echoid-s1379" xml:space="preserve">73. </s>
            <s xml:id="echoid-s1380" xml:space="preserve">To throw a Body into Perſpective, having
              <lb/>
            ſome one or all of its Sides inclined to the Geometri-
              <lb/>
            cal Plane.</s>
            <s xml:id="echoid-s1381" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1382" xml:space="preserve">The Appearances of the Lines forming the
              <lb/>
            Angles of the propoſed Body muſt be found: </s>
            <s xml:id="echoid-s1383" xml:space="preserve">And
              <lb/>
            this may be eaſily done by Prob. </s>
            <s xml:id="echoid-s1384" xml:space="preserve">10. </s>
            <s xml:id="echoid-s1385" xml:space="preserve">
              <note symbol="*" position="right" xlink:label="note-0105-01" xlink:href="note-0105-01a" xml:space="preserve">69.</note>
            takes in all the Caſes. </s>
            <s xml:id="echoid-s1386" xml:space="preserve">And in this Manner the
              <lb/>
            Appearance of a Pyramid, an inclined Priſm,
              <lb/>
            & </s>
            <s xml:id="echoid-s1387" xml:space="preserve">c. </s>
            <s xml:id="echoid-s1388" xml:space="preserve">may be found. </s>
            <s xml:id="echoid-s1389" xml:space="preserve">But nevertheleſs, it hap-
              <lb/>
            pens ſometimes, that the Operations of the pre-
              <lb/>
            cedent Problem may be abbreviated; </s>
            <s xml:id="echoid-s1390" xml:space="preserve">as when
              <lb/>
            the Extremity of ſeveral Lines are found in one
              <lb/>
            and the ſame Line, or when inclined Lines, that
              <lb/>
            have difficult accidental Points, interſect one
              <lb/>
            another, and ſo mutually determine each other.
              <lb/>
            </s>
            <s xml:id="echoid-s1391" xml:space="preserve">This will appear manifeſt by the following Ex-
              <lb/>
            amples.</s>
            <s xml:id="echoid-s1392" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div203" type="section" level="1" n="107">
          <head xml:id="echoid-head113" xml:space="preserve">
            <emph style="sc">Example</emph>
          I.</head>
          <p style="it">
            <s xml:id="echoid-s1393" xml:space="preserve">To throw ſeveral parallel Shores which ſtrengthen a
              <lb/>
            Wall, into Perſpective.</s>
            <s xml:id="echoid-s1394" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1395" xml:space="preserve">I ſuppoſe here that the Baſes of theſe Shores,
              <lb/>
              <note position="right" xlink:label="note-0105-02" xlink:href="note-0105-02a" xml:space="preserve">Fig. 38.</note>
            which are the Places where they meet the Sur-
              <lb/>
            face of the Ground, are all in a right Line, pa-
              <lb/>
            rallel to the Side of the Wall; </s>
            <s xml:id="echoid-s1396" xml:space="preserve">and then the
              <lb/>
            faid Shores may be thrown into Perſpective in
              <lb/>
            the following Manner: </s>
            <s xml:id="echoid-s1397" xml:space="preserve">Having firſt found
              <note symbol="*" position="right" xlink:label="note-0105-03" xlink:href="note-0105-03a" xml:space="preserve">68.</note>
            </s>
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