I never did anything by accident, nor did any of my inventions come by accident; they came by work.

To invent, you need a good imagination and a pile of junk.

Negative results are just what I want. They're just as valuable to me as positive results. I can never find the thing that does the job best until I find the ones that don't.

I find out what the world needs. Then I go ahead and try to invent it.

I am proud of the fact that I never invented weapons to kill.

I start where the last man left off.