Genius is not a retainer to any emperor.

He is not a true man of science who does not bring some sympathy to his studies, and expect to learn something by behavior as well as by application. It is childish to rest in the discovery of mere coincidences, or of partial and extraneous laws. The study of geometry is a petty and idle exercise of the mind, if it is applied to no larger system than the starry one. Mathematics should be mixed not only with physics but with ethics; that is mixed mathematics. The fact which interests us most is the life of the naturalist. The purest science is still biographical.

I do not know at first what it is that harms me. The men and things of to-day are wont to be fairer and truer in to-morrow's memory.

Man makes very much such a nest for his domestic animals, of withered grass and fodder, as the squirrels and many other wild creatures do for themselves.

It is not when I am going to meet him, but when I am just turning away and leaving him alone, that I discover what God is. I say, God. I am not sure that that is the name. You will know what I mean.

Nature abhors a vacuum, and if I can only walk with sufficient carelessness I am sure to be filled.

What youth or maiden conspires with the wild luxuriant beauty of Nature? She flourishes most alone, far from the towns where they reside.