in Thoreau’s Journal:

My shadow has the distinctness of a second person, a certain black companion bordering on the imp, and I ask, “Who is this?” which I see dodging behind me as I am about to sit down on a rock.

No one to my knowledge, has observed the minute differences in the seasons. Hardly two nights are alike. The rocks do not feel warm to-night, for the air is warmest; nor does the sand particularly. A book of the seasons, each page of which should be written out-of-doors, or in its own locality wherever it may be.

When you get into the road, though far from the town, and feel the sand under your feet, it is as if you had reached your own gravel walk. You no longer hear the whip-poor-will, nor regard your shadow, for here you expect a fellow-traveller. You catch yourself walking merely. The road leads your steps and thoughts alike to the town. You see only the path, and your thoughts wander from the objects which are presented to your senses. You are no longer in place.  It is like conformity, —walking in the ways of men.