X-rays ... I am afraid of them. I stopped experimenting with them two years ago, when I came near to losing my eyesight and Dally, my assistant practically lost the use of both of his arms.

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

Everyone steals in commerce and industry. I've stolen a lot, myself. But I know how to steal! They don't know how to steal!

I am so deaf I am debarred from hearing all the time articulation and have to depend on the judgment of others.

I have been at work for some time building an apparatus to see if it is possible for personalities which have left this earth to communicate with us.

I can never pick up a thing without wishing to improve it.

The secret of success is focus of purpose.