6027on PERSPECTIVE.
actly determined, this Method ought not then to
be uſed.
be uſed.
Problem III.
44.
To find the Appearance of the Diviſions of a
Line in the Geometrical Plane.
Line in the Geometrical Plane.
Let A B be a Line, whoſe Appearance is ab.
11Fig. 14. Now to find the Repreſentation of the Diviſions
of this Line, there muſt be Lines drawn from
the Diviſions of the Line to the Eye, whoſe
Interſections with a b will give the Points
ſought.
11Fig. 14. Now to find the Repreſentation of the Diviſions
of this Line, there muſt be Lines drawn from
the Diviſions of the Line to the Eye, whoſe
Interſections with a b will give the Points
ſought.
Note, When theſe Lines very obliquely cut
a b, the following Way ought to uſed.
a b, the following Way ought to uſed.
Method. II.
45.
To find the Repreſentations of the Di-
viſions of the Line G C, make choice of the
22Fig. 14. Point D at Pleaſure without this Line, and find
the Repreſentation d thereof; then draw 3321. through the propoſed Diviſions to the Point D;
and from the Points wherein theſe Lines con-
tinued out cut the Baſe Line, draw other Lines
through the Repreſentation d, which will cut c g
the Repreſentation of C G in the Points ſought.
viſions of the Line G C, make choice of the
22Fig. 14. Point D at Pleaſure without this Line, and find
the Repreſentation d thereof; then draw 3321. through the propoſed Diviſions to the Point D;
and from the Points wherein theſe Lines con-
tinued out cut the Baſe Line, draw other Lines
through the Repreſentation d, which will cut c g
the Repreſentation of C G in the Points ſought.
Problem IV.
46.
To throw a Polygon, or any other regular
Figure on the Geometrical Plane into Perſpective.
Figure on the Geometrical Plane into Perſpective.
The Repreſentation of any Kinds of Figures
may be found by any one of the Methods 4421. Problem I. the fourth in general is the eaſieſt;
and may be firſt uſed in finding the 5522. ſentations of Points, or ſometimes of one
only; and then the fifth Method ſerves 6631.
may be found by any one of the Methods 4421. Problem I. the fourth in general is the eaſieſt;
and may be firſt uſed in finding the 5522. ſentations of Points, or ſometimes of one
only; and then the fifth Method ſerves 6631.