Gravesande, Willem Jacob 's, An essay on perspective

Table of figures

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[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
[61] page 88.Plate. 25.Fig. 60O G F f Z L R P D I T S M a Q E R H N A C B
[62] Plate 26Fig. 61O I F T N S Q S H E R M A
[63] Fig. 62C D S Q L C D R P H
[64] page 96.Plate. 27Fig. 63D E C F M H I G P A Q N
[65] Fig. 64X S D E T C R L F H I G P M B O V Q N
[66] page 98.Plate. 28Fig. 65L M F G D H C E I A B
[67] Fig. 66A B VII VIII IV V H C VI VI P V VII IV S VIII E O I III II I XII XIX IX F D
[68] page 100Plate. 29Fig. 675 6p 7 8 9 10 S V VI VII VIII IX X o XI ll l
[69] Fig. 68c P G e o Q
[70] Fig. 69P c G o e Q
[Figure 71]
[Figure 72]
[Figure 73]
[74] Page 120Plate. 30.Fig. 70.X I F B H D D P O M P R C C C C C E E Q
[75] Plate 31page 120Fig. 71D G C B A H F a I E
[76] Fig. 72P G C H A N B R Q M a F
[77] Fig. 73P G C H D N B I A R Q M a F
[78] Fig. 74G N B C H M a A
[79] Fig. 75D G B C A H F I E a
[80] page 120Plate. 32.Fig. 76.
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            <emph style="sc">Problem</emph>
          VIII.</head>
          <p style="it">
            <s xml:id="echoid-s1089" xml:space="preserve">59. </s>
            <s xml:id="echoid-s1090" xml:space="preserve">To throw a Priſm or Cylinder into Perſpective,
              <lb/>
              <note position="right" xlink:label="note-0079-01" xlink:href="note-0079-01a" xml:space="preserve">Fig. 26.</note>
            both of them being Perpendicular to the Geometri-
              <lb/>
            cal Plane.</s>
            <s xml:id="echoid-s1091" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1092" xml:space="preserve">Let G H I L M N be the Baſe of the Priſm
              <lb/>
            in the Geometrical Plane, and the viſible Part
              <lb/>
            thereof upon the perſpective Plane, let be n g h i;
              <lb/>
            </s>
            <s xml:id="echoid-s1093" xml:space="preserve">then to compleat the Repreſentation of the
              <lb/>
            Priſm, draw Perpendiculars from the Points
              <lb/>
            n g h and i to the Baſe Line, whoſe Length let
              <lb/>
            be ſuch that they may repreſent
              <note symbol="*" position="right" xlink:label="note-0079-02" xlink:href="note-0079-02a" xml:space="preserve">55.</note>
            lars to the Geometrical Plane, equal to the
              <lb/>
            Height of the Priſm, and find the
              <note symbol="*" position="right" xlink:label="note-0079-03" xlink:href="note-0079-03a" xml:space="preserve">50.</note>
            of the other Angular Points of the upper Sur-
              <lb/>
            face of the Priſm, in confidering them as Points
              <lb/>
            elevated above the Geometrical Plane: </s>
            <s xml:id="echoid-s1094" xml:space="preserve">This
              <lb/>
            being done, if the Repreſentations of all the
              <lb/>
            ſaid Angular Points be joyn’d, the whole
              <lb/>
            Priſm will be thrown into Perſpective.</s>
            <s xml:id="echoid-s1095" xml:space="preserve"/>
          </p>
          <p>
            <s xml:id="echoid-s1096" xml:space="preserve">Now to throw a Cylinder into Perſpective,
              <lb/>
            the Repreſentation of its Baſe and upper Sur-
              <lb/>
            face muſt firſt be had, by finding the
              <note symbol="*" position="right" xlink:label="note-0079-04" xlink:href="note-0079-04a" xml:space="preserve">50.</note>
            ance of ſeveral Points of the Periphery of its
              <lb/>
            upper Surface, and then two Perpendiculars
              <lb/>
            muſt be ſo drawn to the Baſe Line, that they
              <lb/>
            may touch the Appearances of the two circular
              <lb/>
            Euds of the Cylinder, and the Appearance of
              <lb/>
            the Cylinder will be had. </s>
            <s xml:id="echoid-s1097" xml:space="preserve">But to avoid uſeleſs
              <lb/>
            Operations, the viſible Part of the Baſe of the
              <lb/>
            Cylinder may be thus determin’d. </s>
            <s xml:id="echoid-s1098" xml:space="preserve">Draw the
              <lb/>
            Line A S from the Point A to the Station Point S,
              <lb/>
            then this Line muſt be biſected in the Point R,
              <lb/>
            about which, as a Centre, and with the Radius
              <lb/>
            R A, the Circular Arc B A C, muſt be deſcrib’d
              <lb/>
            cutting the Baſe of the Cylinder in the </s>
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