I have seen our river, when, the landscape being covered with snow, both water and ice were almost as green as grass. Some consider blue “to be the color of pure water, whether liquid or solid.” But, looking directly down into our waters from a boat, they are seen to be of very different colors. Walden is blue at one time and green at another, even from the same point of view. Lying between the earth and the heavens, it partakes of the color of both. Viewed from a hilltop it reflects the color of the sky; but near at hand it is of a yellowish tint next the shore where you can see the sand, then a light green, which gradually deepens to a uniform dark green in the body of the pond. In some lights, viewed even from a hilltop, it is of a vivid green next the shore. Some have referred this to the reflection of the verdure; but it is equally green there against the railroad sandbank, and in the spring, before the leaves are expanded, and it may be simply the result of the prevailing blue mixed with the yellow of the sand. Such is the color of its iris. This is that portion, also, where in the spring, the ice being warmed by the heat of the sun reflected from the bottom, and also transmitted through the earth, melts first and forms a narrow canal about the still frozen middle.