Drawing is based upon perspective, which is nothing else than a thorough knowledge of the function of the eye.

Truth is so excellent, that if it praises but small things they become noble.

The greatest geniuses sometimes accomplish more when they work less.

He who loves practice without theory is like the sailor who boards ship without a rudder and compass and never knows where he may cast.

Of several bodies, all equally large and equally distant, that which is most brightly illuminated will appear to the eye nearest and largest.

There shall be wings! If the accomplishment be not for me, 'tis for some other. The spirit cannot die; and man, who shall know all and shall have wings.

An artist who lacks the power of self-criticism accomplishes but little. It is good if your work stands higher than your own opinion of it; bad if it is on the same level. But it is a great disaster if your work stands lower than your judgment of it.