I have not failed 700 times. I have not failed once. I have succeeded in proving that those 700 ways will not work. When I have eliminated the ways that will not work, I will find the way that will work.

To me, the idea and expectation that the day is slowly and surely coming when we will be able to honestly say we are our brother's keeper and not his oppressor is very beautiful .

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.

To Monsieur Eiffel the Engineer, the brave builder of so gigantic and original a specimen of modern Engineering from one who has the greatest respect and admiration for all Engineers including the Great Engineer the Bon Dieu.

Time is really the only capital that any human being has, and the only thing he can't afford to lose.

Vision without execution is delusion.

Somewhere between the ages of eleven and fifteen, the average child begins to suffer from an atrophy, the paralysis of curiosity and the suspension of the power to observe. The trouble, I should judge, to lie with the schools.