3211on PERSPECTIVE.
Corollary III.
Corollary IV.
18.
The Appearance of an indefinite Line does not
alter, when the Eye moves in a Line parallel to a
propoſed Line.
alter, when the Eye moves in a Line parallel to a
propoſed Line.
The Repreſentation of this Line, is the In-
terſection of the perſpective Plane, and a Plane
paſſing through the Eye and the ſaid Line. Now
the Eye remains in the ſame Plane, when it
moves in a Line parallel to the propoſed Line;
and conſequently the Appearance of this laſt
Line, will not be changed by that Motion.
terſection of the perſpective Plane, and a Plane
paſſing through the Eye and the ſaid Line. Now
the Eye remains in the ſame Plane, when it
moves in a Line parallel to the propoſed Line;
and conſequently the Appearance of this laſt
Line, will not be changed by that Motion.