oak, and a box of knives is fixed into it, against which the knives in the
revolving wheel are pressed. The beater is divided into two parts--the
working side, in which the cotton is cut and torn between the knife edges
in the revolving cylinder and those in the box; and the running side, into
which the cotton passes after passing under the cylinder. The wheel is
generally boxed in to prevent the cotton from being thrown out during its
revolution. The cotton is thus in constant motion, continually travelling
round, and passing between the knives in the revolving cylinder and those
in the box fixed in the wooden block beneath it. The beater is kept full
of water, and the cotton is gradually reduced to a condition of pulp. The
wheel revolves at the rate of 100 to 150 times a minute.

[Illustration: FIG. 16_a_.--POACHER FOR WASHING GUN-COTTON.]

[Illustration: FIG. 16_b_.--PLAN OF THE POACHER.]

[Illustration: FIG. 16_c_.--ANOTHER FORM OF POACHER.]

When the gun-cotton is judged to be sufficiently fine, the contents of the
beater are run into another very similar piece of machinery, known as the
"poacher" (Fig. 16, _a, b, c_), in which the gun-cotton is continuously
agitated together with a large quantity of water, which can be easily run
off and replaced as often as required. When the material is first run into
the poacher from the beater, the water with which it is then mixed is
first run away and clean water added. The paddle wheel is then set in
motion, and at intervals fresh water is added. There is a strainer at the
bottom of the poacher which enables the water to be drawn off without
disturbing the cotton pulp. After the gun-cotton has been in the poacher
for some time, a sample should be taken by holding a rather large mesh
sieve in the current for a minute or so. The pulp will thus partly pass