My mother was the making of me.

My mind is incapable of conceiving such a thing as a soul. I may be in error, and man may have a soul; but I simply do not believe it.

Of the 200 light bulbs that didn't work, every failure told me something that I was able to incorporate into the next attempt.

We have merely scratched the surface of the store of knowledge which will come to us. I believe that we are now, a-tremble on the verge of vast discoveries - discoveries so wondrously important they will upset the present trend of human thought and start it along completely new lines .

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.

When I have fully decided that a result is worth getting I go ahead of it and make trial after trial until it comes.

There will one day spring from the brain of science a machine or force so fearful in its potentialities, so absolutely terrifying, that even man, the fighter, who will dare torture and death in order to inflict torture and death, will be appalled, and so abandon war forever.