Gravesande, Willem Jacob 's, An essay on perspective

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6229on PERSPECTIVE. drawn to the Point G, will give the Appearance
ſought.
Remarks.
When this Method cannot be us’d, the Per-
ſpective of the Diviſions dividing the Sides of
the Parallelogram, mufl be found .
And we 1144. often oblig’d to have recourſe to this Expedient,
notwithſtanding the accidental Points, G and F,
being had.
And this happens, when the Paralle-
logram is ſo far diſtant from the perſpective
Plane, that its Sides being produc’d, cannot meet
the Baſe Line.
47. Note, moreover, that this one Example
is ſufficient to ſhew how to throw any Kinds of
Figures in the Geometrical Plane into Perſpe-
ctive.
To effect which, we circumſcribe any
Parallelogram about the Figures, which we di-
vide into ſeveral others:
Then we throw this
Parallelogram (thus divided) into Perſpective,
and transfer the given Figure therein, ſo that it
may have the ſame Situation with reſpect to
the little Parallelograms in the perſpective Plane,
as it had in regard to the ſmall Parallelograms
in the Geometrical Plane.
Example III.
48. To throw a circle into Perſpective.
The Repreſentation of ſeveral Points of a
22Fig. 16. Circle, or any other Curve Line requir’d to be
thrown into perſpective, muſt be found, 3321. may be well enough done, by drawing ſeveral
Chords in the Circle, or Curve, parallel between
themſelves, the Repreſentations of which muſt
be found ;
then the Extremities of thoſe 4443.

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