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Show packing. Sometimes they are disks and sometimes cylinders, flat squares, or cubes. If uncompressed and dry the gun cotton would be extremely light, weighing no more than ordinary cotton batting, but when made into the above forms it is compressed to the density of about r, or in other words to a density of an equal amount of water. The percentage of moisture remaining in the gun cotton when it is packed into in-to torpedoes varies between 15 and 30, So safe from explosion, unless detonated, is a brick of wet gun cotton cot-ton that it may be placed upon hot coals. As the moisture dries off from the outside the cotton flakes off and burns up quietly, ' Perfectly dry gun cotton when confined in a strong case will explode with great violence if exposed to a temperature of about 320 degrees Fahrenheit. "Detonation, or the firing of explosives ex-plosives by intense shock, is a modern mod-ern method, for until thirty years ago the application of heat was always al-ways used to bring about an explosion explos-ion , It has npw .been discovered that" detonation produces a more powerful effect than explosion by means of heat. In detonating the wet gun coton in the torpedo heads, the primer of dry gun cotton which is used weighs only a ponnd or thereabout. It is placed in contact with the wet mass, which in a Whitehead White-head torpedo consists usually of about 250 pounds. Then, by means of a fuse and fulminate of mercury cap, a flame is shot through the disk of dry gun cotton. This explodes instantly and with it the entire mass of the wet cotton, producing tremendous tremend-ous results. The question of precisely pre-cisely how detouation takes place-that place-that is, how so small an initial explosion ex-plosion can suffice to' decompose an unlimited quantity of high explosives behind it has caused much argument argu-ment and many speculations. Ber-telot Ber-telot gives as an explanation that 'the shock of the primary explosion communicates to the layer of molecules mole-cules in the immediate proximity an enormously active force, whereby the 'molecular ed fice' is shaken to pieces and the initial force is augmented aug-mented to a degree corresponding to the heat evolved by decomposition. decomposi-tion. A new shock is thereby produced pro-duced in the next layer, and the action is repeated and so propagated propagat-ed until the whole moleclar system is completely destroyed. Brad-streets. . GU1T COTTON. 'The process by which so common com-mon and harmless a substance as cotton is converted into a hiuh explosive is a comparatively simple one," says the Springfield Republican. Republi-can. "Pure. raw cotton or ordinary, cotton waste is steeped in a solution of one part of nitric acid and three parts of sulphuric acid. The nitric acid is the one which renders the cotton explosive, the presence of the sulphuric being required only to absorb ab-sorb the water, thus allowing the other acid to combine more readily with the nearly pure cellulose of which cotton consists. After the cotton has soaked in the acids for several hours, it is taken from the pots , and squeezed through heavy rollers to extract all the superfluous acid- which it has not absorbed Th en -it - i s (washed : caref u 1 ly-aird thoroughly, still with the same object ob-ject of removing the free acid. If any of this remained, its tendency would be to cause chemical changes in the gun cotton and decompose it. I Formerly, this washing was the last1 process resorted to for the removal of j tfie free acid, but a few years ago' Sir Frederick Abel found that the j cells in the cotton fiber so absorbed ' and retained the acid by capillary attraction that the washing failed to extract it entirely. To remedy this and make the gnn cotton, more pure it is now, after being washed, passed through a. machine similar . to that which grinds up the rags in a. paper mill. Here it is crushed thoroughly and afterward washed again until the last trace of free acid disappears, and the cotton comes out in the form of a soft, white pulp closely resembling resemb-ling the pulp of which paper is made. This concludes the process of actual manufacture, and it now remains only to convert the gun cotton cot-ton into the most convenient form for the use to which it is to he put. If it is to be employed in making powder it; is dried and stored away in pulverized form, but if it is designed de-signed for filling torpedoes it must be cgmpressed to a certain desity and molded into the shapes which will best enable it to be packed into in-to the torpedo - heads. These shapes vary according to the design of the torpedoes and the method of |