I never failed. It just didn't work 10,000 times.

The only time I really become discouraged is when I think of all the things I would like to do and the little time I have in which to do them.

Discontent is the first necessity of progress.

Not only will atomic power be released, but someday we will harness the rise and fall of the tides and imprison the rays of the sun.

Fooling around with alternating currents is just a waste of time. Nobody will use it, ever. It's too dangerous . . . it could kill a man as quick as a bolt of lightning. Direct current is safe.

The biggest failure of man is that he gives up before he realizes how close he was to success.

I told [Kruesi] I was going to record talking, and then have the machine talk back. He thought it absurd. However, it was finished, the foil was put on; I then shouted "Mary had a little lamb," etc. I adjusted the reproducer, and the machine reproduced it perfectly. On first words spoken on a phonograph.