Vows begin when hope dies.

Here is a thing which the more it is needed the more it is rejected: and this is advice, which is unwillingly heeded by those who most need it, that is to say, by the ignorant.

Perspective is the rein and rudder of painting.

The good painter must paint two things: a person and the essence of his soul.

Truth was the only daughter of Time.

I say that the power of vision extends through the visual rays to the surface of non-transparent bodies, while the power possessed by these bodies extends to the power of vision.

Experiment is the sole interpreter of the artifices of Nature.