Who would have suspected so large and cold and thick-skinned a thing to be so sensitive? Yet it has its law to which it thunders obedience when it should as surely as the buds expand in the spring. The earth is all alive and covered with papillae. The largest pond is as sensitive to atmospheric changes as the globule of mercury in its tube. One attraction in coming to the woods to live was that I should have leisure and opportunity to see the Spring come in. The ice in the pond at length begins to be honeycombed, and I can set my heel in it as I walk. Fogs and rains and warmer suns are gradually melting the snow; the days have grown sensibly longer; and I see how I shall get through the winter without adding to my wood-pile, for large fires are no longer necessary. I am on the alert for the first signs of spring, to hear the chance note of some arriving bird, or the striped squirrel's chirp, for his stores must be now nearly exhausted, or see the woodchuck venture out of his winter quarters. On the 13th of March, after I had heard the bluebird, song sparrow, and red-wing, the ice was still nearly a foot thick. As the weather grew warmer it was not sensibly worn away by the water, nor broken up and floated off as in rivers, but, though it was completely melted for half a rod in width about the shore, the middle was merely honeycombed and saturated with water, so that you could put your foot through it when six inches thick; but by the next day evening, perhaps, after a warm rain followed by fog, it would have wholly disappeared, all gone off with the fog, spirited away. One year I went across the middle only five days before it disappeared entirely. In 1845 Walden was first completely open on the 1st of April; in '46, the 25th of March; in '47, the 8th of April; in '51, the 28th of March; in '52, the 18th of April; in '53, the 23d of March; in '54, about the 7th of April. Every incident connected with the breaking up of the rivers and ponds and the settling of the weather is particularly interesting to us who live in a climate of so great extremes. When the warmer days come, they who dwell near the river hear the ice crack at night with a startling whoop as loud as artillery, as if its icy fetters were rent from end to end, and within a few days see it rapidly going out. So the alligator comes out of the mud with quakings of the earth. One old man, who has been a close observer of Nature, and seems as thoroughly wise in regard to all her operations as if she had been put upon the stocks when he was a boy, and he had helped to lay her keel -- who has come to his growth, and can hardly acquire more of natural lore if he should live to the age of Methuselah -- told me -- and I was surprised to hear him express wonder at any of Nature's operations, for I thought that there were no secrets between them -- that one spring day he took his gun and boat, and thought that he would have a little sport with the ducks. There was ice still on the meadows, but it was all gone out of the river, and he dropped down without obstruction from Sudbury, where he lived, to Fair Haven Pond, which he found, unexpectedly, covered for the most part with a firm field of ice. It was a warm day, and he was surprised to see so great a body of ice remaining. Not seeing any ducks, he hid his boat on the north or back side of an island in the pond, and then concealed himself in the bushes on the south side, to await them.