All sounds are sharper in winter; the air transmits better. At night I hear more distinctly the steady roar of the North Mountain. In summer it is a sort of complacent purr, as the breezes stroke down its sides; but in winter always the same low, sullen growl.

The overall quantity of nuclear weapons in the world continues to decline slowly.

I seldom go into a natural history museum without feeling as if I were attending a funeral.

The floating vapour is just as true an illustration of the law of gravity as the falling avalanche.

When nature made the blue-bird she wished to propitiate both the sky and the earth, so she gave him the color of the one on his back and the hue of the other on his breast.

Science sees the process of evolution from the outside, as one might a train of cars going by, and resolves it into the physical and mechanical elements, without getting any nearer the reason of its going by, or the point of its departure or destination.

One resolution I have made, and try always to keep, is this: ‘To rise above little things’.