I never once failed at making a light bulb. I just found out 99 ways not to make one.

We haven't failed. We now know a thousand things that won't work, so we are much closer to finding what will.

Today, I am wondering what would have happened to me by now, if, fifty years ago, some fluent talker had converted me to the theory of the eight-hour day and convinced me that it was not fair to my fellow-workers to put forth my best efforts in my work? I am glad that the eight-hour day had not been invented when I was a young man. If my life had been made up of eight-hour days, I don't believe I could have accomplished a great deal.

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 start where the last man left off. What the mind of man can conceive and believe, the mind of a man can achieve.

Good fortune is what happens when opportunity meets with planning.

I think that Ingersoll had all the attributes of a perfect man, and, in my opinion, no finer personality ever existed. Judging from the past, I cannot help thinking that the intention of the Supreme Intelligence that rules the world is to ultimately make such a type of man universal.