The object of the present paper is to describe the results obtained and the mode of experimenting adopted in some determinations which I have made of the specific heats of solutions of salts. These experiments form part of a series which I am at present carrying out on the physical changes produced when salts are dissolved in different amounts of their solvents. From such an investigation I believe much information may be gained regarding the nature of solution.

The method of experimenting adopted in the experiments described below was that of mixtures; but as regards the mode in which the exact amount of heat added to the solution was measured, it differed from any process with which I am acquainted. This peculiarity consisted in using as heater a thin glass bottle of about 50 cubic centimetres capacity, and furnished with a long glass neck, just wide enough to allow an ordinary mercury-in-glass thermometer to pass through. This bottle was nearly filled with mercury, in which was immersed the bulb of a sensitive thermometer, and thus the temperature of the mercury in the bottle could be read off at any instant. The graduation of this thermometer was to fifths of a degree centigrade, and had been compared with the Kew standards. The distance between two consecutive divisions of its scale was about one millimetre.