in Thoreau’s Journal:
This day, too, has that autumnal character. I am struck by the clearness and stillness of the air, the brightness of the landscape, or, as it were, the reflection of light from the washed earth, the darkness and heaviness of the shade, as I look now up the river at the white maples and bushes, and the smoothness of the stream. If they are between you and the sun, the trees are more black than green. It must be owing to the clearness of the air since the rains, together with the multiplication of the leaves, whose effect has not been perceived during the mists of the dog-days. But I cannot account for this peculiar smoothness of the dimpled stream – unless the air is stiller than before – nor for the peculiar brightness of the sun’s reflection from its surface. I stand on the south bank, opposite the black willows, looking up the full stream, which, with a smooth, almost oily and sheeny surface, comes welling and dimpling onward, peculiarly smooth and bright now at 4 P. M., while the numerous trees seen up the stream – white maples, oaks, etc. – and the bushes look absolutely black in the clear, bright light.