235on PERSPECTIVE.
Points of Diſtance, are two Points in the Hori-
33Def. 13. zontal Line, each way diſtant from the Point of Sight
by the length of the principal Ray; as MN.
33Def. 13. zontal Line, each way diſtant from the Point of Sight
by the length of the principal Ray; as MN.
The Geometrical Line, is a Line, that paſſes
44Def. 14. through the Station Point, and is parallel to the baſe
Line, as A B.
44Def. 14. through the Station Point, and is parallel to the baſe
Line, as A B.
CHAP. II.
3.
THE Perſpective, or Appearance of a
Right Line, as A B, which being con-
tinued, does not paſsthrough the Eye O, is like-
77Fig. 3. wiſe a right Line: For the Rays, by which the
Line A B is perceived, form a Plane cutting
the perſpective Plane; and the common Section
of theſe two Planes is a right Line, as a b.
Right Line, as A B, which being con-
tinued, does not paſsthrough the Eye O, is like-
77Fig. 3. wiſe a right Line: For the Rays, by which the
Line A B is perceived, form a Plane cutting
the perſpective Plane; and the common Section
of theſe two Planes is a right Line, as a b.