My main purpose in life is to make money so I can afford to go on creating more inventions.

There is time for everything.

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!

I never did anything worth doing by accident, nor did any of my inventions come indirectly through accident, except the phonograph. No, when I have, fully decided that a result is worth getting, I go about it, and make trial after trial, until it comes.

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 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.

Show me a thoroughly satisfied man - and I will show you a failure.