EXPLOSIONS AND EXPLOSIVES. 783 



The latter dissolves the former, and the result is an elastic, gelatinous, 

 semi-transparent mass, which is easily cut or torn apart, and shows no 

 trace whatever of nitro-glycerine on handling. Its explosive proper- 

 ties are unaffected by contact with water, and in this respect it is the 

 most useful of all the high explosives for military purposes. With 

 the change in the physical condition of the two components comes 

 also a change in the ease of explosion; these two bodies, each of itself 

 highly explosive, form when united one which is quite the reverse. 

 When unconfined, a primer of fifty grains of fulminate will cause 

 the explosion of but a very small portion of a charge, the rest be- 

 ing torn in pieces ; if, however, it be strongly confined, so that the 

 blow of the fulminate exerts its whole force, which is propagated 

 through the gelatine, it then explodes with a violence as great as that 

 of nitro-glycerine, if not somewhat greater. This latter point has not 

 been fully determined, but the probabilities are that the expansion of 

 the constituents of the gelatine is more complete and is accompanied 

 with more heat than is the case with nitro-glycerine alone. The gela- 

 tine freezes at 40 Fahr., and in this state is fired with no difficulty 

 whatever, being in this respect much superior to dynamite. When 

 subjected to a pressure of two hundred and fifty pounds to the square 

 inch, no nitro-glycerine is separated ; the union between the two con- 

 stituents seems to be complete and definite. If subjected to the action 

 of flame, it takes fire less readily than dynamite, but burns very much 

 like it, with perhaps a greater strength of flame, as if urged by a bel- 

 lows. When heated to 100 it softens, but does not become at all 

 greasy, and there is no exudation of nitro-glycerine. Explosion by 

 the application of heat takes place at about 420 ; but it is found 

 that by the addition of a small amount of camphor, say four per cent, 

 it will bear an increased heat of 100 before explosion. Experiments 

 made with the gelatine thus camphorated show that the camphor exer- 

 cises no deleterious effect upon the strength of the material, while 

 rendering it less like jelly, and more like that form of confection 

 known as fig-paste. Six per cent of camphor may be added without 

 harm, but any greater quantity materially diminishes the explosive 

 effect. Portions of this gelatine, both pure and camphorated, have 

 been subjected to a constant heat of 100 for more than six weeks, 

 and no exudation of the dangerous nitro-glycerine has been observed. 

 It will not explode under circumstances which ordinarily render cer- 

 tain the detonation of either nitro-glycerine or dynamite that is to 

 say,' a quantity of the gelatine will resist the shock of the detona- 

 tion of another quantity placed within a very few feet of it ; if very 

 near, it may take fire and burn, but detonation will not ensue unless 

 the two masses are almost in actual contact, and even then it will not 

 always occur. It further possesses the property of permitting the im- 

 pact of a ball from a gun without exploding, while both dynamite and 

 gun-cotton may be readily detonated by a blow of this kind. All 



