After water is reduced to about 39 deg., instead of obeying the common law of becoming heavier by cooling, it forms a remarkable exception to it, and becomes lighter until it freezes. Were it not for this admirable provision of Nature, all our ponds and rivers would, in the Winter, become solid ice from the surface to the bottom. Now as the surface water is chilled it goes to the bottom, and is replaced by warmer water, which rises, until the whole is reduced to the point of greatest density. Then the circulation ceases, and the water colder than 39 deg. remains at the surface, is converted into ice which becomes still lighter, by crystallization, and floats upon the surface. No experiments, showing the temperature of undrained soils at various depths, in the United States, have come to our knowledge. Mr. Gisborne says: "Many experiments have shown that, in retentive soils, the temperature, at two or three feet below the surface of the water-table, is, at no period of the year, higher than from 46 deg. to 48 deg. in agricultural Britain." Prof. Henry states in the Patent Office Report for 1857, that in the cellars of the observatory, at Paris, at the depth of sixty-seven and a half feet, in fifty years, the temperature has never varied a tenth of a degree from 53 deg. 28', in all that period, Summer or Winter. Mr. Parkes gives the results of a valuable series of experiments, in which he compared the temperature of drained and undrained portions of a bog. He found the temperature of the undrained portion to remain steadily at 46 deg., at all depths, from one to thirty feet; and at seven inches from the surface, the temperature remained at 47 deg. during the experiments. During the same period, the temperature of the drained portion was 48-1/4 deg. at two feet seven inches below the surface, and at seven inches, reached as high as 66 deg. during a thunder-storm; while, on a mean of thirty-five observations, the temperature at the latter depth was 10 deg. higher than at the same depth in the undrained portion of the bog. We find in the "Agriculture of New York," the results of observations made at Albany and at Scott, in that State, in the year 1848, upon temperature at different depths. The condition of the soil is not described, but it is presumed that it was soil naturally drained in both cases. A few of the results may give the reader some idea of the range of underground temperature, as compared with that of the air.