3 minutes, the thermometer _a_, rose to 77 deg.. 5 " " fell to 76-1/2 deg.. 15 " " " 70-1/2 deg.. 20 " " remained at 71 deg.. 1 hour 50 " " " " 70-1/2 deg.. "In these two experiments, the thermometer at the bottom of the box suddenly rose a few degrees immediately after the hot water was added; and it might be inferred that the heat was carried downwards by the water. But, in reality, the rise was owing to the action of the hot water on the thermometer, and not to its action upon the cold water. To prove this, the perpendicular thermometers were removed. The box was filled with peat and water to within three inches of the top, a horizontal thermometer, _a f_, having been previously secured through a hole made in the side of the box, by means of a tight-fitting cork, in which the naked stem of the thermometer was grooved. A gallon of boiling water was then added. The thermometer, a very delicate one, was _not in the least affected_ by the boiling water in the top of the box. "In this experiment, the wooden box may be supposed to be a field; the peat and cold water represent the water-logged portion; rain falls on the surface, and becomes warmed by contact with the soil, and, thus heated, descends. But it is stopped by the cold water, and the heat will go no further. But, if the soil is drained, and not water-logged, the warm rain trickles through the crevices of the earth, carrying to the drain-level the high temperature it had gained on the surface, parts with it to the soil as it passes down, and thus produces that bottom heat which is so essential to plants, although so few suspect its existence." Water, although it will not conduct heat downwards, is a ready vehicle of cold from the surface towards the bottom. Water becomes heavier by cooling till it is reduced to about 39 deg., at which point it attains its greatest density, and has a tendency to go to the bottom until the whole mass is reduced to this low temperature. Thus, the circulation of water in the saturated soil, in some conditions of the temperature of the surface and subsoil, may have a chilling effect which could not be produced on drained soil.