You sometimes speak of gravity as essential and inherent to matter. Pray do not ascribe that notion to me, for the cause of gravity is what I do not pretend to know, and therefore would take more time to consider of it.

A cylinder of air reaching to the top of the atmosphere is of equal weight with a cylinder of water about 33 feet high.

What Descartes did was a good step. You have added much several ways, and especially in taking the colours of thin plates into philosophical consideration. If I have seen a little further it is by standing on the shoulders of Giants.

This thing is but a puny imitation of a much grander system whose laws you know, and I am not able to convince you that this mere toy is without a designer or maker; yet you profess to believe that the great original from which the design is taken has come into being without either designer or maker! Now tell me by what sort of reasoning do you reach such an incongruous conclusion?

I shall not mingle conjectures with certainties.

The latest authors, like the most ancient, strove to subordinate the phenomena of nature to the laws of mathematics.

He who thinks half-heartedly will not believe in God; but he who really thinks has to believe in God.