Nothing will be left, Nothing in the air, nothing under the earth, nothing in the waters. All will be exterminated.

One has no right to love or hate anything if one has not acquired a thorough knowledge of its nature. Great love springs from great knowledge of the beloved object, and if you know it but little you will be able to love it only a little or not at all.

The first object of the painter is to make a flat plane appear as a body in relief and projecting from that plane

A man of supreme folly: his life flies away while he is merely hoping to enjoy it.

The variety of colour in objects cannot be discerned at a great distance, excepting in those parts which are directly lighted up by the solar rays.

Avoid studies of which the result dies with the worker.

O speculators about perpetual motion, how many vain chimeras have you created in the like quest? Go and take your place with the seekers after gold.