To despise theory is to have the excessively vain pretension to do without knowing what one does, and to speak without knowing what one says.

Our sun enlightens the planets that belong to him; why may not every fixed star also have planets to which they give light?

Neatness is a crowning grace of womanhood.

Women react differently: a French woman who sees herself betrayed by her husband will kill his mistress; an Italian will kill her husband; a Spaniard will kill both; and a German will kill herself.

In vain we shall penetrate more and more deeply the secrets of the structure of the human body, we shall not dupe nature; we shall die as usual.

As astronomy is the daughter of idleness, geometry is the daughter of property.

Hardly anyone knows how much is gained by ignoring the future.