Whoever despises the high wisdom of mathematics nourishes himself on delusion and will never still the sophistic sciences whose only product is an eternal uproar.

Nature varies the seed according to the variety of the things she desires to produce in the world.

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.

Intellectual passion dries out sensuality.

No human investigation can be called real science if it cannot be demonstrated mathematically.

Who sows virtue ought to reap honour.

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