1879. J on Recent Detonating Agents. 83 



blasting gelatine of small proportions of certain substances rich in 

 carbon and hydrogen, which arc soluble in nitrn-glycerinc, such as 

 benzol and nitro-bcnzol, increases to a remarkable extent the non- 

 sensitiveness to detonation of the original material ; and this obser- 

 vation has led to experiments being conducted by engineer officers in 

 Austria, with a view of endeavouring to convert the blasting gelatine 

 into a material wliich should compete, as regards some special advan- 

 tages in point of stifety, with wet gun-cotton in its application to 

 military and naval purposes, and especially as regards non-liability 

 to detonation or explosion by the impact of rifle bullets. If boxes 

 containing dry compressed gun-cotton are fired into from small arms 

 even at a short range, the gun-cotton is generally inflamed, but has 

 never been known to explode ; the sharpness of the blow essential to 

 the hitter result, which the bullet might otherwise give, being 

 diminished by its penetration through the side of the box before 

 reaching the exi^losive. It is scarcely necessary to state that wet gun- 

 cotton, containing even as little as 15 per cent, of water, is never 

 inflamed under these conditions. On the other hand, dynamite is 

 invariably detonated when struck by a bullet on passing through the 

 side of the box, and blasting gelatine, though so much less sensitive 

 than dynamite, behaves in the same way in its ordinary as well as in 

 the frozen condition. The Austrian experiments indicated that the 

 gelatine when intimately mixed with only 1 per cent, of camphor^ 

 generally, though not invariably, escaped explosion by the impact of 

 a bullet, but that when the proportion of camphor amounted to 4 per 

 cent, the material was neither exploded nor inflamed, though, in the 

 frozen state, it was still liable to occasional explosion. These 

 results were considered indicative of a degree of safety in regard 

 to service exigencies, approaching that of wet compressed gun-cotton. 

 The camphoretted gelatine still labours, however, under the disad- 

 vantage of being readily inflammable, and of burning fiercely, and 

 consequently, of giving rise, like dynamite and dry gun-cotton, to 

 violent explosion, or detonation, if burned in considerable bulk ; a 

 result which was explained by the lecturer in his discourse delivered 

 at the Eoyal Institution in 1872. Moreover, the camphoretted 

 blasting gelatine is so difficult of detonation by the means ordinarily 

 applied, that a large initiative charge of a very violent detonating 

 mixture consisting of pure specially prepared trinitrocellulose and 

 nitro-glycerine is prescribed, by the Austrian experimenters, as being 

 indispen-able to its proper detonation. 



The action of camphor and of other substances rich in carbon and 

 hydrogen in reducing greatly the sensitiveness to detonation of the 

 preparation of soluble gun-cotton and nitro-glycerine, is not to be 

 traced to any physical modification of that material produced by the 

 addition of such substances, and no satisfactory theory can at present 

 be advanced to account for it on chemical grounds. 



The camphoretted gelatine, like Nobel's original gelatine itseK, 

 may be kept immersed in water for a considerable time without any 



G 2 



