When cut, the beets are covered with boiling water in a macerator of wood or iron for one hour, the water should contain 4.4 of sulphuric acid to every 2200 lbs. of beets. After this, the water is drawn off into a second vat in which are placed more beets, and allowed to macerate again for an hour. This is repeated a third time in another vat, and the juice, which has now acquired a density equal to that obtained by rasping, is run off into the fermenting vat. When the first vat is empty it is immediately refilled with boiling water and fresh beets; the juice from this operation is run into the second vat, when the contents of that one are run into the third. To continue the operation, the beets are completely exhausted by being macerated for an hour with a third charge of boiling water (acidulated as in the former case). The exhausted pulp is removed to make room for fresh slices; and the first vat is then charged with juice which has already passed through the second and third vats. After macerating the fresh beets for one hour, the charge is ready for fermentation. In ordinary weather, the juice should now be at the right heat for this process, viz., about 71.1∞ or 75.2∞ F., but in very cold weather it may require some re-heating. In Fig. 50 is shown a series of vats for the extraction of the sugar from beets such as is termed a "diffusion battery." [Illustration: FIG. 50.--Diffusion Battery.] The vessels, 1, 2, 3 and 4 are of wood or sheet iron. Each vessel has a bottom sieve and a top sieve between which the beet slices are to be placed. From the bottom of each vessel below the sieve a pipe _D_ runs to the top of the vessel next in order. From the bottom of the last vessel 4 of the series a pipe _C_ runs back to the top of the one first used. Pipes _A_ and _B_ are connected to each vessel for the admission of water and spent wash respectively. A discharge pipe _E_ leads from each vessel to a collecting vat 5. Maceration and diffusion is accomplished as follows: The sliced beets are placed between the sieves in vessel 1 and water or spent wash at a temperature of 185∞ F. is let in and the beets allowed to macerate for three-quarters of an hour, meanwhile tub 2 is charged with sliced beets. The cock or pipe _D_ between the vessels is opened when the time, three quarters of an hour, has elapsed; hot water or spent wash is admitted by pipes _A_ or _B_ to the vessel 1, which forces the sugar solution therein into vessel 2. When the required amount of fluid has been passed into 2 from 1, the inlet of water into 1 is stopped, and the vessel heated to 185∞ F. Vessel 3 is charged with beet slices and in three-quarters of an hour vessels 1, 2 and 3 are connected and water or wash admitted into 1, which forces the solution in 1 into 2 and that in 2 into 3 when it is again raised to 185∞ F.