in Thoreau’s Journal:

Looking up through this soft and warm southwest wind, I notice the conspicuous shadow of Middle Conanturn Cliff, now at 3 p. m., and elsewhere the shade of a few apple trees, —their trunks and boughs.  Through this warm and hazy air the sheeny surface of the hill, now considerably greened, looks soft as velvet, and June is suggested to my mind. It is remarkable that shadow should only be noticed now when decidedly warm weather comes, though before the leaves have expanded, i. e., when it begins to be grateful to our senses. The shadow of the Cliff is like a dark pupil on the side of the hill. This first shadow is as noticeable and memorable as a flower. I observe annually the first shadow of this cliff. When we begin to pass from sunshine into shade for our refreshment; when we look on shade with yearning as on a friend. That cliff and its shade suggests dark eyes and eyelashes and overhanging brows. Few things are more suggestive of heat than this first shade, though now we see only the tracery of tree-boughs on the greening grass and the sandy street.

This I notice at the same time with the first bumblebee, when the Rana palustris purrs in the meadow generally, the white willow and aspen display their tender green full of yellow light, the parti-colored warbler is first heard over the swamp, the woodchuck, who loves warmth, is out on the hillsides in numbers, the jingle of the chip-bird is incessantly heard, the thrasher sings incessantly, the first cricket is heard in a warm rocky place, and that scent of vernal flowers is in the air. This is an intenser expression of that same influence or aspect of nature which I began to perceive ten days ago (vide 25th), —the same lieferung.