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.

In winter the stars seem to have rekindled their fires, the moon achieves a fuller triumph, and the heavens wear a look of a more exalted simplicity.

Nature will not be conquered, but gives herself freely to her true lover - to him who revels with her, bathes in her seas, sails her rivers, camps in her woods, and with no mercenary ends, accepts all.

I am not going to advocate ... the abandoning of the improved modes of travel; but I am going to brag as lustily as I can on behalf of the pedestrian, and show how all the shining angels second and accompany the man who goes afoot, while all the dark spirits are ever looking out for a chance to ride.

The tendinous part of the mind, so to speak, is more developed in winter; the fleshy, in summer. I should say winter had given the bone and sinew to literature, summer the tissues and the blood.

You cannot use [nuclear weapons] to target civilians; you cannot use them against military targets if they have indiscriminate effects on civilians in addition to the attack on the military target.

Nature is not benevolent; Nature is just, gives pound for pound, measure for measure, makes no exceptions, never tempers her decrees with mercy, or winks at any infringement of her laws.