in Thoreau’s Journal:

There is a fine effluence surrounding the wood, as if the sap had begun to stir and you could detect it a mile off. Such is the difference between an object seen through a warm, moist, and soft air and a cold, dry, hard one. Such is the genialness of nature that the trees appear to have put out feelers by which our senses apprehend them more tenderly. I do not know that the woods are ever more beautiful, or affect me more.

I feel it to be a greater success as a lecturer to affect uncultivated natures than to affect the most refined, for all cultivation is necessarily superficial, and its roots may not even be directed toward the centre of the being.

Rivers, too, like the walker, unbutton their icy coats, and we see the dark bosoms of their channels in the midst of the ice. Again, in pools of melted snow, or where the river has risen, I look into clear, placid water, and see the russet grassy bottom in the sun….

As we sit in this wonderful air, many sounds — that of woodchopping, for one — come to our ears agreeably blunted or muffled, even like the drumming of a partridge, not sharp and rending as in winter and recently. If a partridge should drum in winter, probably it would not reverberate so softly through the wood and sound indefinitely far. Our voices, even, sound differently and betray the spring. We speak as in a house, in a warm apartment still, with relaxed muscles and softened voices. The voice, like a woodchuck in his burrow, is met and lapped in and encouraged by all genial and sunny influences. There may be heard now, perhaps, under south hillsides and the south sides of houses, a slight murmur of conversation, as of insects, out of doors.

These earliest spring days are peculiarly pleasant. We shall have no more of them for a year. I am apt to forget that we may have raw and blustering days a month hence. The combination of this delicious air, which you do not want to be warmer or softer, with the presence of ice and snow, you sitting on the bare russet portions, the south hillsides, of the earth, this is the charm of these days. It is the summer beginning to show itself like an old friend in the midst of winter. You ramble from one drier russet patch to another. These are your stages. You have the air and sun of summer, over snow and ice, and in some places even the rustling of dry leaves under your feet, as in Indian-summer days.