Though I may not . . . be able to quote other authors, I shall rely on that which is much greater and more worthy - on experience.

Weight is caused by one element being situated in another; and it moves by the shortest line towards its centre, not by its own choice, not because the centre draws it to itself, but because the other intervening element cannot withstand it.

Perspective is nothing more than a rational demonstration applied to the consideration of how objects in front of the eye transmit their image to it, by means of a pyramid of lines. The Pyramid is the name I apply to the lines which, starting from the surface and edges of each object, converge from a distance and meet in a single point.

Study me, reader, if you delight in me, because on very few occasions shall I return to the world, and because the patience for this profession is found in very few, and only in those who wish to compose things anew. Come, oh men, to see the miracles that such studies will disclose to nature.

Even the richest soil, if left uncultivated will produce the rankest weeds.

Men born in hot countries love the night because it refreshes them and have a horror of light because it burns them.

Everything comes from everything, and everything is made out of everything, and everything returns into everything.