The San Francisco call., 1898-03-20
Dangers Involved in Compromising Dynamite, Nitro-GIycerine, Gun Cotton and Other Deadly
 Agents Used in War.

handle and less liable to explosion from shock than is the case with pure nitro glycerine. Dynamite freezes at 40 deg. It is always frozen for transportation;
 it explodes at 360 deg. To thaw It is dangerous unless done with the great est care Ninety-f1ve per cent of .he accidents in mines due to explosions Of dynamite have been owing to the care lessness of thaWing. In blasting dyna- mite is very extensively used, though generally it goes under the name of powder For submarine mines, planted in a channel to obstruct the fairway, dynamite is extensively used. It is put up ip copper spheres or cylinders, which are anchored so as to float ten or twelve feet below the surface, or still lower; to these are connected cleo tric fuses, operated by an electric cir cult from the shore. Pressing key will cause the fuse to detonate the dynamite and the explosion follows.
 Gun cotton, however, is more exten- sively used for military purposes than any other form of high explosive. It is produced by the action of concen- trated nitric acid on cotton or cellu- lose. After compression the white cakes resulting look very much like ordinary hard-pressed cotton, white and hard. Gun cotton is unaffected by water This is one of it's most valuable properties and one which makes gun cotton so valuable for use on board ships in torpedoeS, or wherever under water explosives are needed. Dry loose gun cotton is harmless; if burned it flashes off. Dry compressed gun cotton burns rapidly but quickly if uncon- fined, and moist gun cotton does the same. Wet gun cotton cannot be ex- ploded except by certain kinds of deto- nators-it may be treated without dan ger; it may be even forced into or placed in a shell and shot out of gun, yet it still remains intact. These are most important characteristics of wet gun cotton You might have maga- zines full of it, instead of one or two torpedo heads, yet fire on board ship or a shot from an enemy or an explo- sion from within or without will not detonate this wet gun cotton. Gun cot ton is always stored and used wet. Dis titled water is used to wet it and keep it wet; in this condition it is the safest explosive known. In one of the naval intelligence publications it is stated that the English Government tested the safety of gun cotton containing 30 per cent moisture by burning bonflreS in two lots of ton each. In one case the explosive was in disks in closed tank, and in the other 1t was divided among eighty closed packages. In both cases the gun cotton burned away without explosion.
 Tn order to explode moist gun cotton a special kind of primer or detonator must be used, consisting of disk of dry gun cotton, and this dry gun cotton is exploded by illuminate of mercury fuse fired by electricity These disks of gun cotton may be made any size. Usually they are about four inches in diameter and an inch thick, with hole in the center. Several disks of wet gun cotton are placed one over the other; near the top is put one layer or disk Of dry cotton, then the electric primer is lowered into the charge through the hole, and the entire cartridge is care fully sealed up with a Water-ught head through which the electric wires lead, which are to be spliced to the wires leading to the firing battery. It is of the utmost importance to keep this dry gun cotton dry. Should it get wet the fuse would be imperative. When gun cotton is used to charge the war heads of torpedoes, the gu-4 cotton is usually molded to fit the form of the chamber designed to hold it.
 Guncotton is not so extensively used | for commercial submarine operations
 as some of the nitro glycerine com | pounds, mainly because of the diff culty of preparing it for firing. Nor IS it so terrible in its explosive action as some of them. A form of gelatine seems to be more generally preferred. One of these now on the market is called Repauno gelatine. It is described as high explosive powder, having a gelatinous consistency. It is, therefore, sticky and very dense or heavy-two very advantageous features in certain