187'J.] on Hcccni Detonat'mij Agents. 79 



ing only from 7 to 10 per cent, of soluble gun-cotton with 90 to 

 93 per cent, of nitroglycerine, the wliolo becomes converted into 

 jin adhesive jdastic material, more gummy than gelatinous in cha- 

 racter, from which, if it be i)rei)ared with suflficient care, no nitro- 

 glycerine will separate even by its exposure to heat in contact with 

 bibulous paj^er, or by its prolonged immersion in water, the com- 

 ponents being not easily susceptible of separation even through the 

 agency of a solvent of both. As the nitro-glycerine is only diluted 

 with a small proportion of a solidfying agent w^iich is itself an 

 explosive (though a somewhat feeble one), this hlasting gelatine, as 

 Nobel has called it, is more powerful not only than dynamite but 

 also than the mixture of a smaller quantity of nitro-glycerine with 

 the most explosive gun-cotton, as the liquid substance is decidedly 

 the most violent explosive of the two. Moreover, as nitro-glycerine 

 contains a small amount of oxygen in excess of that required for the 

 perfect oxidation of its carbon and hydrogen constituents, while the 

 soluble gun-cotton is deficient in the requisite oxygen for its com- 

 plete transformation into thoroughly oxidised products, the result 

 of an incorporation of the latter in small proportion with nitro- 

 glycerine, is the i^roduction of an explosive agent which contains the 

 proportion of oxygen requisite for the development of the maximum 

 of chemical energy by the complete burning of the carbon and 

 hydrogen, and hence this blasting gelatine should, theoretically, be 

 even slightly more powerful as an explosive agent than pure nitro- 

 glycerine. 



That such is the case has been well established by numerous 

 experiments, but although this blasting gelatine may be detonated 

 like dynamite by means of small quantities of confined detonating 

 composition, when it is employed in strongly tamped blast-holes, or 

 under conditions very favourable to the development of great initial 

 pressure, it behaves very differently from that material, or other 

 solid though plastic preparations of nitro-glycerine, if the attempt is 

 made to detonate it when freely exposed to the air or only partially 

 confined. It not only needs a much more considerable amount of 

 strongly confined detonating composition than dynamite and similar 

 preparations do, to bring about a detonation with it under those 

 conditions; but when as much as 15 or 20 grains of confined 

 fulminate are detonated in direct contact with it, although a sharp 

 explosion occurs, little or no destructive action results, and a con- 

 siderable portion of the charge operated upon is dispersed in a finely- 

 divided condition. This dispersion appears to take place to some 

 slight extent with dynamite also, when a small charge is detonated in 

 open air, in consequence of its want of rigidity, though the amount 

 of explosive which thus escapes detonation is very small as compared 

 with the gelatine. 



In comparing the effects of these nitro-glycerine preparations with 

 each other and with compressed gun-cotton and preparations of it, 

 by detonating equal quantities quite unconfined upon iron plates, the 



