A diffusion battery, or the apparatus in which the process of diffusion is carried on, consists of a number of tanks or cells, usually from ten to fourteen, cylindrical in shape and terminating in truncated cones provided with covers. There are two ways of arranging the cells of a diffusion battery; in the one case the cells are placed in a straight line; in the other they are grouped in a circle. These cells are filled with cossettes in rotation, and water is introduced into the one in which the cossettes were first placed. Thus the water enters the tank in which the cossettes are nearly exhausted of their sugar, and it flows successively through the other cells that contain cossettes of greater sugar content until the last cell, or the one containing fresh cossettes, is reached. The juice passing through this cell is alternately sent to the measuring tank or to the next cell, which has just been filled with fresh cossettes. The process is continuous, one cell being emptied of exhausted cossettes while another is being filled with fresh ones, and the juice flowing either to the measuring tank or to the freshly filled cell. The exhausted cossettes, now called pulp, are dropped from the bottom of the diffusion tanks into a large bin, from which they are conveyed or pumped to pulp separators and presses for the separation of the surplus water. This pressed pulp is usually stored in large bins or silos, where it is allowed to ferment before being fed to cattle. Recently the practice of drying the pulp has been carried on to a large extent. In this process the moisture in the pulp is reduced to ten per cent, the same proportion as in cured hay. Dried to this point, it is packed in bags and may be stored for an indefinite period without deteriorating. After being treated thus it forms an excellent stock food, particularly if waste molasses is sprayed on it before drying. PURIFICATION OF JUICE, CARBONATION AND FILTRATION The diffusion juice obtained as above described is quite dark in color, and after passing through the measuring tanks it is conveyed to carbonation tanks where it is treated with from three to four per cent of caustic lime in the form of a thick milk. [Illustration: _By permission of Truman G. Palmer, Esq._ DIFFUSION BATTERY—SHOWING DIFFUSION CELLS IN CIRCULAR ARRANGEMENT] [Illustration: _By permission of Truman G. Palmer, Esq._ DIFFUSION BATTERY—SHOWING DIFFUSION CELLS IN STRAIGHT LINES] After being thoroughly agitated, the mixture is treated with carbonic acid gas obtained from the lime-kilns, as the result of the decomposition of limestone and the combustion of the fuel used for burning it.