I am afraid of radium and polonium ... I don't want to monkey with them.

We shall have no better conditions in the future if we are satisfied with all those which we have at present.

I am both pleased but astonished by the fact that mankind has not yet begun to use all the means and devices that are available for destruction. I hope that such weapons are never manufactured in quantity.

Invention is 1% inspiration and 99% perspiration

Your worth consists in what you are and not in what you have.

Incurably religious, that is the best way to describe the mental condition of so many people.

Of all my inventions, I liked the phonograph best