The eye transmits its own image through the air to all the objects which face it, and also receives them on its own surface, whence the "sensus communis" takes them and considers them.

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

Men born in hot countries love the night because it refreshes them and have a horror of light because it burns them.

Learning acquired in youth arrests the evil of old age.

Men of lofty genius when they are doing the least work are most active.

There is no higher or lower knowledge, but one only, flowing out of experimentation.

What induces you, oh man, to depart from your home in town, to leave parents and friends, and go to the countryside over mountains and valleys, if it is not for the beauty of the world of nature?