In addition to a destructor, there is at the Burmautofts depot a "carbonizer" kiln, in which the sweepings of the vegetable markets are burned into charcoal. The carbonizer consists of eight vertical cells, in two sets or stacks of four, separated by a space containing two double furnaces, back to back, there being a double furnace also at each end of the eight cells. Each of the stacks of four cells is 15 feet 6 inches high; the ends and middle parts, forming the tops of the furnaces, being 6 feet high. The block of brick work containing the eight cells and furnaces is 26 feet 6 inches long and 12 feet 4 inches wide at the floor level. Each cell is 3 feet 6 inches by 2 feet, and about 10 feet deep, with a chamber below about 3 feet deep, into which the charred material falls and is completely burned. The top of the cells is level with the upper platform, and they are fed through a loose cover, which is immediately replaced. Inside the cells cast-iron sloping shelves are hung upon the walls so that their upper edges touch the walls, but the lower edges are some inches off, so that the hot air of the furnaces passes upward behind the shelves round the four sides of the cell in a spiral manner, and out near the top into a vertical flue, which conducts it down to the horizontal flue at the bottom, which leads to the chimney. The charcoal is withdrawn from the bottom of the heating chamber through a sliding plate 2 feet above the floor, and is wheeled red hot to the charcoal cooler, which is a revolving cylinder, nearly horizontal, kept cool by water falling upon it, and delivers the charcoal in two degrees of fineness at the end. It is worked by a small attached engine, supplied with steam from the boiler before mentioned. Each cell of the carbonizer can reduce to charcoal 50 cwt. of vegetable refuse in twenty four hours, but at Leeds not quite so much is put through. The quantity of market refuse passed through six cells of the carbonizer varies from 3 to 10 tons a day, and averages about 4½ tons, from which 15 cwt. of charcoal is obtained. The fuel for burning the charcoal is derived from the ash pit refuse, some selected loads being for that purpose passed over a sloping screen fixed between the upper platform and the furnace floor, the fine ashes which pass through the screen being taken away to the manure heaps, and the combustible parts to the furnaces of the carbonizer. In this way a good deal of the ash pit refuse is got rid of; it is often one-twelfth part of the whole quantity. The carbonizer and the destructor are set 33 feet apart, to allow room for drawing the furnaces and for the mortar mills, but the space is hardly sufficient. One man is employed in attending to the carbonizer.