Perspective—Proposition.
Objects that are farther off can never be so large but that those in front, though smaller, will conceal or surround them.
Definition.
This proposition can be proved by experiment. For if you look through a small hole there is nothing so large that it cannot be seen through it and the object so seen appears surrounded and enclosed by the outline of the sides of the hole. And if you stop it up, this small stopping will conceal the view of the largest object.
The apparent size of objects defined by calculation (99-105)
99.