The memory of benefits is a frail defence against ingratitude.

Anyone who invokes authors in discussion is not using his intelligence but his memory.

If you cause your ship to stop and place the head of a long tube in the water and place the outer extremity to your ear, you will hear ships at a great distance from you.

When Fortune comes, seize her in front with a sure hand, because behind she is bald.

Constancy does not begin, but is that which perseveres.

Although human ingenuity may devise various inventions which, by the help of various instruments, answer to one and the same purpose, yet will it never discover any inventions more beautiful, more simple or more practical than those of nature, because in her inventions there is nothing lacking and nothing superfluous; and she makes use of no counterpoise when she constructs the limbs of animals in such a way as to correspond to the motion of their bodies, but she puts into them the soul of the body.

True and great love springs out of great knowledge, and where you know little you can love but little or not at all.