The Book of the science of Mechanics must precede the Book of useful inventions.

The acquisition of knowledge is always of use to the intellect, because it may thus drive out useless things and retain the good. For nothing can be loved or hated unless it is first known.

Any color is more distinctly seen when opposed to its contrary: thus, black on white, blear near yellow, green near red, and so on.

An arch consists of two weaknesses which, leaning one against the other, make a strength.

Painting is poetry that is seen rather than felt, and poetry is painting that is felt rather than seen.

Experience does not err. Only your judgments err by expecting from her what is not in her power.

In rivers, the water that you touch is the last of what has passed and the first of that which comes; so with present time.