The world owes nothing to any man, but every man owes something to the world.

To have a great idea, have a lot of them.

We will make electricity so cheap that only the rich will burn candles.

It is the best book ever written on the subject. There is nothing like it!

The Bible of nature is the best damn Bible in the world. Its laws are perfect and grand, and all the prayers in the world can't change them. There is intelligence and law in this world, and there may be supreme intelligence and law, but so far as the religion of the day is concerned, it is all a damned fake.

Nearly every man who develops an idea works it up to the point where it looks impossible, and then he gets discouraged. That's not the place to become discouraged.

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 .