My entire delight was in observing without being myself noticed,— if I could have been invisible, all the better. I was absolutely interested in men and their ways, as I was interested in marmots and chamois, in tomtits and trout. If only they would stay still and let me look at them, and not get into their holes and up their heights! The living inhabitation of the world — the grazing and nesting in it, — the spiritual power of the air, the rocks, the waters, to be in the midst of it, and rejoice and wonder at it, and help it if I could, — happier if it needed no help of mine, — this was the essential love of Nature in me, this the root of all that I have usefully become, and the light of all that I have rightly learned.

Praeterita, volume I, chapter IX (1885-1889).