in Thoreau’s Journal:

Again I am advertised of the approach of a new season, as yesterday. The air is not only warmer and stiller, but has more of meaning or smothered voice to it, now that the hum of insects begins to be heard. You seem to have a great companion with you, are reassured by the scarcely audible hum, as if it were the noise of your own thinking. It is a voiceful and significant stillness, such as precedes a thunder-storm or a hurricane. The boisterous spring winds cease to blow, the waves to dash, the migrating ducks to vex the air so much. You are sensible of a certain repose in nature.