in Thoreau’s Journal:

The blue flag (Iris versicolor) enlivens the meadow. The lark sings at sundown off in the meadow. It is a note which belongs to a New England summer evening. Though so late, I hear the summer hum of a bee in the grass, as I am on my way to the river behind Hubbard’s to bathe. After hoeing in a dusty garden all this warm afternoon, —so warm that the baker says he never knew the like and expects to find his horses dead in the stable when he gets home, —it is very grateful to wend one’s way at evening to some pure and cool stream and bathe therein.