Page:A Treatise on Painting.djvu/189

 without rudder or compass, and therefore cannot be certain of arriving at the wished-for port.

Practice must always be founded on good theory; to this, Perspective is the guide and entrance, without which nothing can be well done.   is to Painting what the bridle is to a horse, and the rudder to a ship.

The size of a figure should denote the distance at which it is situated.

If a figure be seen of the natural size, remember that it denotes its being near to the eye.   outlines or contours of bodies are so little perceivable, that at any small distance between that and the object, the eye will not be able to recognise the features of a friend or relation, if it were not for their clothes and general appearance. So that by the knowledge of the whole it comes to know the parts.   Perspective consists in giving, by established rules, the true dimensions of objects, according to their respective distances; so that the second object be less than the first, the third than the second, and by degrees at last they become invisible. I find by experience, that, if the second object be at Rh