I have a peculiar theory about radium, and I believe it is the correct one. I believe that there is some mysterious ray pervading the universe that is fluorescing to it. In other words, that all its energy is not self-constructed but that there is a mysterious something in the atmosphere that scientists have not found that is drawing out those infinitesimal atoms and distributing them forcefully and indestructibly.

I am long on ideas, but short on time. I expect to live to be only about a hundred.

Somewhere between the ages of eleven and fifteen, the average child begins to suffer from an atrophy, the paralysis of curiosity and the suspension of the power to observe. The trouble, I should judge, to lie with the schools.

The secret of success is focus of purpose.

A genius is a talented person who does his homework.

Oh these mathematicians make me tired! When you ask them to work out a sum they take a piece of paper, cover it with rows of A's, B's, and X's and Y's ... scatter a mess of flyspecks over them, and then give you an answer that's all wrong!

First be sure a thing is wanted or needed, then go ahead.