To speak well of a base man is much the same as speaking ill of a good man.

A bird is an instrument working according to mathematical law, which instrument it is within the capacity of man to reproduce with all its movements.

You do ill if you praise, but worse if you censure, what you do not understand.

Inaction saps the vigor of the mind.

A single and distinct luminous body causes stronger relief in the objects than a diffused light; as may be seen by comparing one side of a landscape illuminated by the sun, and one overshadowed by clouds, and illuminated only by the diffused light of the atmosphere.

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.

Anyone who conducts an argument by appealing to authority is not using his intelligence; he is just using his memory.