You cannot imagine the craving for rest that I feel-a hunger and thirst. For six long days, since my work was done, my mind has been a whirlpool, swift, unprogressive and incessant, a torrent of thoughts leading nowhere, spinning round swift and steady.

The Athenian democracy suffered much from that narrowness of patriotism which is the ruin of all nations.

Few people who know of the work of Langley, Lilienthal, Pilcher, Maxim and Chanute but will be inclined to believe that long before the year 2000 A.D., and very probably before 1950, a successful aeroplane will have soared and come home safe and sound.

If anything is possible, then nothing is interesting

Non-violence is the policy of the vegetable kingdom.

When the history of civilization is written, it will be a biological history and Margaret Sanger will be its heroine.

I do not believe I have any immortality. The greatest evil in the world today is the Christian religion