in Thoreau’s Journal:

The peculiarity of to-day is that now first you perceive that dry, warm, summer-presaging scent from dry oak and other leaves, on the sides of hills and ledges. You smell the summer from afar. The warmth makes a man young again. There is also some dryness, almost dustiness, in the roads. The mountains are white with snow, and sure as the wind is northwest it is wintry; but now it is more westerly. The edges of the mountain snow melt into the sky. It is affecting to be put into communication with such distant objects by the power of vision, —actually to look into rich lands of promise. In this spring breeze, how full of life the silvery pines, probably the under sides of their leaves. Goose Pond is wholly open. Unexpectedly dry and crispy the grass is getting in warm places.