I have discovered the secret of happiness - it is work, either with the hands or the head. The moment I have something to do, the draughts are open and my chimney draws, and I am happy.

Basically [United States and France] said "We will use nuclear weapons whenever it suits our purposes to do so." So this expansion of doctrines regarding possible use of nuclear weapons makes them more, you know, sort of, salient and important and so it's increasing the perceived political value of nuclear weapons and therefore causing or contributing to possible proliferation.

[Theodore Roosevelt] was a naturalist on the broadest grounds, uniting much technical knowledge with knowledge of the daily lives and habits of all forms of wild life. He probably knew tenfold more natural history than all the presidents who had preceded him, and, I think one is safe in saying, more human history also.

The most precious things of life are near at hand, without money and without price. Each of you has the whole wealth of the universe at your very door. All that I ever had, and still have, may be yours by stretching forth your hand and taking it.

One goes to Nature only for hints and half-truths. Her facts are crude until you have absorbed them or translated them ... It is not so much what we see as what the thing seen suggests.

It is always easier to believe than to deny. Our minds are naturally affirmative.

I think rain is as necessary to the mind as to vegetation. My very thoughts become thirsty, and crave the moisture.