Never say, "I tried it once and it did not work."

We are rather like children, who must take a watch to pieces to see how it works.

A good scientific theory should be explicable to a barmaid.

You know, I am sorry for the poor fellows that haven't got labs to work in.

If your experiment needs statistics, you ought to have done a better experiment.

Gentlemen, we have run out of money. It is time to start thinking.

Should a young scientist working with me come to me after two years of such work and ask me what to do next, I would advise him to get out of science. After two years of work, if a man does not know what to do next, he will never make a real scientist.