1869.] 



Mr. F. A. Abel on Explosive Agents. 



395 



stomach, to constitute the gastric juice, the free hydrochloric acid, acid 

 phosphates and chlorides, and the albuminoid bodies and disintegrated 

 tissue (the pepsine ?) to act in the liquefaction of food. 



II. " Contributions to the History of Explosive Agents." By 

 F. A. Abel, F.R.S., For. Sec. C. S. Received March 9, 1868. 



(Abstract.) 



The degree of rapidity with which an explosive substance undergoes 

 metamorphosis, as also the nature and results of such change, are, in the 

 greater number of instances, susceptible of several modifications by varia- 

 tion of the circumstances under which the conditions essential to chemical 

 change are fulfilled. 



Excellent illustrations of the modes by which such modifications may be 

 brought about are furnished by gun-cotton, which may be made to burn 

 very slowly, almost without flame, to inflame with great rapidity, but 

 without development of great explosive force, or to exercise a violent de- 

 structive action, according as the mode of applying heat, the circumstances 

 attending such application of heat, and the mechanical condition of the 

 explosive agent, are modified*. The character of explosion and the 

 mechanical force developed, within given periods, by the metamorphosis 

 of explosive mixtures such as gunpowder, is similarly subject to modi- 

 fications ; and even the most violent explosive compounds known (the 

 mercuric and silver fulminates, and the chloride and iodide of nitrogen) 

 behave in very different ways, under the operation of heat or other dis- 

 turbing influences, according to the circumstances which attend the meta- 

 morphosis of the explosive agent {e.g. the position of the source of heat 

 with reference to the mass of the substance to be exploded, or the extent 

 of initial resistance opposed to the escape of the products of explosion). 



Some new and striking illustrations have been obtained of the suscepti- 

 bility to modification in explosive action possessed by these substances. 



The product of the action of nitric acid upon glycerine, known as nitro- 

 glycerine or glonoine, which bears some resemblance to chloride of nitrogen 

 in its power of sudden explosion, requires the fulfilment of special condi- 

 tions for the development of its explosive force. Its explosion by the 

 simple application of heat can only be accomplished if the source of heat 

 be applied, for a protracted period, in such a way that chemical decom- 

 position is established in some portion of the mass, and is favoured by the 

 continued application of heat to that part. Under these circumstances, 

 the chemical change proceeds with very rapidly accelerating violence, and 

 the sudden transformation, into gaseous products, of the heated portion 

 eventually results, a transformation which is instantly communicated 



* Proceedings of the Eoyal Society, vol. xiii. pp. 205 et seq. 



