Gravesande, Willem Jacob 's, An essay on perspective

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        <div xml:id="echoid-div390" type="section" level="1" n="210">
          <pb o="119" file="0195" n="224" rhead="on PERSPECTIVE."/>
          <p>
            <s xml:id="echoid-s2578" xml:space="preserve">46. </s>
            <s xml:id="echoid-s2579" xml:space="preserve">When we have a mind to remove this
              <lb/>
            Machine from one place to another, we lay the
              <lb/>
            Box B E C upon the croſs Pieces 2, 3, 4, 5, with
              <lb/>
            its opening A B C upwards; </s>
            <s xml:id="echoid-s2580" xml:space="preserve">then we put the
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            little Box Y, the Ruler and Mirrour (mentioned
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            Numb. </s>
            <s xml:id="echoid-s2581" xml:space="preserve">13.) </s>
            <s xml:id="echoid-s2582" xml:space="preserve">the black Cloth, and the two Sticks
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            M L and I H, all into the ſaid great Box; </s>
            <s xml:id="echoid-s2583" xml:space="preserve">and
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            afterwards partly cover it by the Frame G,
              <note symbol="*" position="right" xlink:label="note-0195-01" xlink:href="note-0195-01a" xml:space="preserve">40.</note>
            which is ſuſtained by two very thin Rulers, and
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            then by another little Board, when the Frame is
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            not big enough. </s>
            <s xml:id="echoid-s2584" xml:space="preserve">The whole Machine thus taken
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            to pieces, will take up no more room than the
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            Support itſelf doth: </s>
            <s xml:id="echoid-s2585" xml:space="preserve">and ſo it is very eaſy to re-
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            move from Place to Place. </s>
            <s xml:id="echoid-s2586" xml:space="preserve">Now when Objects
              <lb/>
            are to be repreſented in this Machine, it muſt be
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            put together again, as per Figure; </s>
            <s xml:id="echoid-s2587" xml:space="preserve">and the black
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            Cloth, for a Perſon to put his Head under, hang-
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            ing upon the Sticks, and faſtned to the Sides of
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            the opening A B, A C, and C D.</s>
            <s xml:id="echoid-s2588" xml:space="preserve"/>
          </p>
        </div>
        <div xml:id="echoid-div394" type="section" level="1" n="211">
          <head xml:id="echoid-head231" style="it" xml:space="preserve">The Uſe of this Machine.</head>
          <p>
            <s xml:id="echoid-s2589" xml:space="preserve">47. </s>
            <s xml:id="echoid-s2590" xml:space="preserve">The Uſe of this Second Machine is the
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            fame as that of the Firſt; </s>
            <s xml:id="echoid-s2591" xml:space="preserve">but it ought to be ob-
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            ſerved, that when we incline the Machine,
              <note symbol="*" position="right" xlink:label="note-0195-02" xlink:href="note-0195-02a" xml:space="preserve">43.</note>
            Angle of Inclination of the Mirrour and Hori-
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            zon muſt be made leſs, by half the Inclination of
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            the Bottom of the Box; </s>
            <s xml:id="echoid-s2592" xml:space="preserve">and when the Machine
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            is ſomewhat inclin’d backwards, the ſaid
              <note symbol="*" position="right" xlink:label="note-0195-03" xlink:href="note-0195-03a" xml:space="preserve">44.</note>
            muſt be made greater by a like half. </s>
            <s xml:id="echoid-s2593" xml:space="preserve">You muſt
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            likewiſe obſerve, that when Objects are to be
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            repreſented for a perpendicular Picture, the Ma-
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            chine muſt be placed according to the former
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            Part of Numb. </s>
            <s xml:id="echoid-s2594" xml:space="preserve">44. </s>
            <s xml:id="echoid-s2595" xml:space="preserve">Prints muſt be faſtned to a
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            Board entirely ſeparated from the Machine, which
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            Board muſt be ſet upon a Support, that may
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            conveniently be moved backwards or forwards,
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            according to Neceſſity.</s>
            <s xml:id="echoid-s2596" xml:space="preserve"/>
          </p>
        </div>
      </text>
    </echo>
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