A Treatise on Painting/Chapter 119
Chap. CXIX.—A Picture is to be viewed from one Point only.
This will be proved by one single example. If you mean to represent a round ball very high up, on a flat and perpendicular wall, it will be necessary to make it oblong, like the shape of an egg, and to place yourself (that is, the eye, or point of view) so far back, as that its outline or circumference may appear round.