in Thoreau’s Journal:

4 PM. Annursnack  The under sides of the leaves exposed by the breeze give a light blueish tinge to the woods as I look down on them. Looking at the woods west of this hill there is a grateful dark shade under their eastern sides where they meet the meadows––their cool night side––a triangular segment of night to which the sun has set. The mts look like waves on a blue ocean tossed up by a stiff gale. The rhexia Virginia is in bloom.