I never was so rapid in my virtue but my vice kept up with me.

The study of geometry is a petty and idle exercise of the mind, if it is applied to no larger system than the starry one. Mathematics should be mixed not only with physics but with ethics; that is mixed mathematics.

The hounding of a dog pursuing a fox or other animal in the horizon may have first suggested the notes of the hunting-horn to alternate with and relieve the lungs of the dog. This natural bugle long resounded in the woods of the ancient world before the horn was invented.

If I am not I, who will be?

Summer passes into autumn in some unimaginable point of time, like the turning of a leaf.

He who rides and keeps the beaten track studies the fences chiefly.

The news we hear, for the most part, is not news to our genius. It is the stalest repetition.