regular current in the water in the direction of the arrows, by which the rags are drawn between the cutters of the cylinder and the teeth of the block; this cuts them to pieces: they are then thrown over the top of the breasting upon the inclined plane, down which they slowly slide and pass round the partition, and in about twenty minutes are again brought between the teeth of the cylinder and the block. The mode in which the rags are cut will be understood by considering that the teeth of the block are placed somewhat inclined to the axis of the cylinder, while the teeth of the cylinder are parallel to its axis, so that the cutting edges meet at a small angle and pass over each other something like the blade of a pair of shears, and the rags between them are cut up in a similar manner; and as they are brought many times under the action of the cutters, and must necessarily present their fibres each time in different directions, they are reduced to the condition of pulp. [Illustration: Fig. 5.--BEATING-ENGINE.] The beater, with sixty teeth, and twenty to twenty-four cutters in the block, makes 180,000 cuts per minute, the effect of which is a low musical note or hum, audible at a distance from the mill. In the washing-engine the rags are opened, their fibres separated, and the dirt removed. Any small solid impurities are collected in the trough _a_, Fig. 4. When first put in the beating-engine, the rags are worked gently, the cylinder is raised some way above the block, so as to rub rather than cut the rags; at the same time a copious stream of water is admitted; after twenty or thirty minutes, the cylinder is let down so as to cut the rags, and the operation is at first so violent that the cylinder is often jerked or heaved up. After three or four hours the engine works steadily; the rags are cut up very small, and form what is called _half stuff_; this is let out into a basket, which retains it while the water flows off. For some kinds of paper the half stuff is left to mellow, or ferment; but it is usual at this stage to _bleach_ the stuff, which is done by a solution of chloride of lime, in stone vats, or by using this solution instead of water in the engine at the last stage of the washing process, the slides _g g_ being put down in the cover to prevent the loss of the solution. In the course of an hour, the yellow rags or half stuff are converted into a snow white. This is then put into the beating-engine, and in four or five hours it is ground into a fine pulp, a little water being let in from time to time, but none being allowed to escape. The quality of the water has considerable influence on that of the paper; the purest water is of course the best; water from chalky soils introduces lime into the pulp, and this forms a slight incrustation upon the moulds, which is washed off from time to time by vinegar.