Why are the bones of great fishes, and oysters and corals and various other shells and sea-snails, found on the high tops of mountains that border the sea, in the same way in which they are found in the depths of the sea?

Just as iron rusts from disuse, and stagnant water putrefies, or when cold turns to ice, so our intellect wastes unless it is kept in use.

The memory of benefits is a frail defence against ingratitude.

Most men are of naught more use in their lives but as machines for turning food into sh*t.

He who wishes to see how the soul inhabits the body should look to see how that body uses its daily surroundings. If the dwelling is dirty and neglected, the body will be kept by its soul in the same condition, dirty and neglected.

A luminous body will appear more brilliant in proportion as it is surrounded by deeper shadow.

The Book of the science of Mechanics must precede the Book of useful inventions.