One can have no smaller or greater mastery than mastery of oneself.

O Time with your teethy years! You swallow up all things little by little in a slow-motion, wrinkling process of dying.

Life, when is spent well, is long.

A day will come in which men will look upon an animal's murder the same way they look today upon a man's murder.

Perspective is nothing more than a rational demonstration applied to the consideration of how objects in front of the eye transmit their image to it, by means of a pyramid of lines. The Pyramid is the name I apply to the lines which, starting from the surface and edges of each object, converge from a distance and meet in a single point.

As every divided kingdom falls, so every mind divided between many studies confounds and saps itself.

I have discovered that a screw-shaped device such as this, if it is well made from starched linen, will rise in the air if turned quickly.