for five minutes (10-1/2 lbs. of waste acids are removed from each charge
dipped). The charge is then washed in a very similar manner to that
previously described, and again wrung out in a centrifugal extractor
(1,200 revolutions per minute). The gun-cotton is now boiled by means of
steam in wooden tanks for eight hours; it is then again wrung out in the
extractors for three minutes, boiled for eight hours more, and again wrung
out; it is then sent to the beater and afterwards to the poacher. The
poachers hold 1,500 gals. each, or 18 cwt. of cotton. The cotton remains
six hours in the poachers. Before moulding, 500 gals. of water are run
into the poacher, and 500 gals. of lime water containing 9 lbs. of whiting
and 9 gals. of a caustic soda solution. This mixture is of such a strength
that it is calculated to leave in the finished gun-cotton from 1 to 2 per
cent. of alkaline matter.

By means of vacuum pressure, the pulp is now drawn off and up into the
stuff chest--a large cylindrical iron tank, sufficiently elevated on iron
standards to allow room for the small gauge tanks and moulding apparatus
below. It holds the contents of one poacher (18 cwt.), and is provided
with revolving arms to keep the pulp stirred up, so that it may be
uniformly suspended in water.

Recently a new process, invented by J.M. and W.T. Thomson (Eng. Pat. No.
8,278, 1903), has been introduced at the Waltham Abbey Factory. The object
of this invention is the removal of the acids of nitration from the
nitrated material after the action has been completed, and without the aid
of moving machinery, such as presses, rollers, centrifugals, and the like.
The invention consists in the manufacture of nitrated celluloses by
removing the acids from the nitrated cellulose directly by displacement
without the employment of either pressure or vacuum or mechanical
appliances of any kind, and at the same time securing the minimum dilution