2 o6 THE POPULAR SCIENCE MONTHLY. 



from impurity. With the mere washing of the beets the sugar 

 manufacturer is not content ; they are therefore freed from those 

 parts which are poor in saccharine, damaged or otherwise unde- 

 sirable, by a machine called a carousal. 



When cleaned, the beets are thrown from the wash-barrel into 

 a hopper, from which they pass into an endless elevator which 

 carries them to the top floor, where they are discharged into a 

 large hopper. They then pass into a cage which will hold one 

 thousand pounds of beets, and, when this weight is indicated, 

 the cage empties its load into the cutter or slicer, Fig. 5. The cage 

 and the indicator enable the factory people to closely estimate 

 the amount of raw material used each day. It is also a check 

 on every department. It will show any error that may arise in 

 the receiving or shipping departments. The slicer is a round 

 iron shaft, rotating horizontally, and fitted with steel knives ca- 

 pable of slicing four hundred tons of beets in twenty-four hours. 

 The rotating knives, which descend upon the beets, cut them 

 into thin slices, thus exposing the sugar-cells, which is an impor- 

 tant factor in the diffusion system. The lower end of the cutter 

 opens into a wooden trough about two feet square, on the bottom 

 of which is an endless belt. As the sliced beets fall from the 

 cutter, the belt carries them along to the diffusion tanks. 



In alluding to the operation of the diffusion battery in the arti- 

 cle on "Growth of the Beet-Sugar Industry," it was said that 

 " though simple in its conception, it nevertheless illustrates well- 

 known laws of chemical science in the transfusion of liquids, and 

 successfully opens the membranous walls of the sugar-cells of the 

 plant, giving a higher grade of juice, with less gummy, nitroge- 

 nous, and fibrous impurities, at less cost than by the old methods 

 of mechanical pressure." By membranous diffusion is understood 

 the process of exchange between two fluids of unequal density, 

 contained in two vessels separated only by a membrane. Sup- 

 posing the sugar-cells to be brought in contact with pure water, 

 then, theoretically, if the cells contain twelve per cent of sugar, 

 transfusion will go on till an equal weight of water contains six 

 per cent of sugar, while by the passage of water into the cells the 

 juice there is reduced to the same degree. Taking the six-per-cent 

 watery solution and treating with it fresh roots containing twelve 

 per cent of sugar, a nine-per-cent solution will be obtained, which, 

 on being brought a third time in contact with fresh roots, would 

 be raised to a density of 10*5 per cent. Thus, seven eighths of 

 the whole sugar would be obtained at the third operation, and it 

 is on this theory that the diffusion process is based. 



A diffusion battery, Fig. 6, consists of a range of twelve large, 

 close, upright cylinders called diffusers, provided with man-holes 

 above and perforated false bottoms, with a like number of heaters, 



