order to remove this, the cotton has to be compressed by hydraulic power.
The dry compressed gun-cotton is packed in boxes containing 2,500 lbs. of
dry material. In order to ascertain how much of the wet cotton must be put
into the press, it is necessary to determine the percentage of water. This
may be done by drying 2,000 grains upon a paper tray (previously dried at
100° C.) in the water oven at 100° C. for three hours, and re-weighing and
calculating the percentage of water. It is then easy to calculate how much
of the wet gun-cotton must be placed in the hopper of the press in order
to obtain a block of compressed cotton of the required weight. Various
forms of presses are used, and gun-cotton is sent out either as solid
blocks, compressed discs, or in the form of an almost dry powder, in zinc-
lined, air-tight cases. The discs are often soaked in water after
compression until they have absorbed 25 per cent. of moisture.

[Illustration: FIG. 17.--OLD METHOD. 100 PIECES.]

[Illustration: FIG. 18.--NEW METHOD. ONE SOLID BLOCK.]

At the New Explosives Company's Stowmarket Works large solid blocks of
gun-cotton are pressed up under a new process, whereby blocks of gun-
cotton, for use in submarine mines or in torpedo warheads, are produced.
Large charges of compressed gun-cotton have hitherto been built up from a
number of suitably shaped charges of small dimensions (Fig. 17), as it has
been impossible to compress large charges in a proper manner. The
formation of large-sized blocks of gun-cotton was the invention of Mr A.
Hollings. Prior to the introduction of this method, 8 or 9 lbs. had been
the limit of weight for a block. This process has been perfected at the
Stowmarket factory, where blocks varying from the armour-piercing shell
charge of a few ounces up to blocks of compressed gun-cotton mechanically
true, weighing 4 to 5 cwts. for torpedoes or submarine mines, are now