Thoreau writes in his journal:
A still and rather warm morning, with a very thick haze concealing the sun and threatening to turn to rain.
It is a smooth, April-morning water, and many sportsmen are out in their boats. I see a pleasure boat, on the smooth surface away by the Rock, resting lightly as a feather in the air.
By 4 P.M. it began to rain gently or mizzle. Saw this afternoon a great many of those little fuzzy gnats in the air.