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Mr. F. A. Abel on Explosive Agents. [Apr. 15, 



throughout the mass of nitroglycerine, so that' confinement of the sub- 

 stance is not necessary to develope its full explosive force. This result 

 can be obtained more expeditiously and with greater certainty by exposing 

 the substance to the concussive action of a detonation produced by the 

 ignition of a small quantity of fulminating powder, closely confined and 

 placed in contact with, or proximity to, the nitroglycerine. 



The development of the violent explosive action of nitroglycerine, freely 

 exposed to air, through the agency of a detonation, was regarded until 

 recently as a peculiarity of that substance ; it is now demonstrated that 

 gun-cotton and other explosive compounds and mixtures do not necessarily 

 require confinement for the full development of their explosive force, but 

 that this result is attainable (and very readily in some instances, especially 

 in the case of gun-cotton) by means similar to those applied in the case of 

 nitroglycerine. 



The manner in which a detonation operates in determining the violent 

 explosion of gun-cotton, nitroglycerine, &c, has been made the subject of 

 careful investigation. It is demonstrated experimentally that the result 

 cannot be ascribed to the direct operation of the heat developed by the 

 chemical changes of the charge of detonating material used as the ex- 

 ploding agent. An experimental comparison of the mechanical force ex- 

 erted by different explosive compounds, and by the same compound em- 

 ployed in different ways, has shown that the remarkable power possessed 

 by the explosion of small quantities of certain bodies (the mercuric and 

 silver-fulminates) to accomplish the detonation of gun-cotton, while com- 

 paratively very large quantities of other highly explosive agents are inca- 

 pable of producing that result, is generally accounted for satisfactorily by 

 the difference in the amount of force suddenly brought to bear in the 

 different instances upon some portion of the mass operated upon. Most 

 generally, therefore, the degree of facility with which the detonation of a 

 substance will develope similar change in a neighbouring explosive sub- 

 stance may be regarded as proportionate to the amount of force developed 

 within the shortest period of time by that detonation, the latter being, in 

 fact, analogous in its operation to that of a blow from a hammer, or of the 

 impact of a projectile. 



Several remarkable results of an exceptional character have been ob- 

 tained, which indicate that the development of explosive force under the 

 circumstances referred to is not always simply ascribable to the sudden 

 operation of mechanical force. These were especially observed in the 

 course of a comparison of the conditions essential to the detonation of gun- 

 cotton and of nitroglycerine by means of particular explosive agents (chlo- 

 ride of nitrogen, &c), as well as in an examination into the effects pro- 

 duced upon each other by the detonation of those two substances. 



The explanation offered of these exceptional results is to the effect that 

 the vibrations attendant upon a particular explosion, if synchronous with 

 those which would result from the explosion of a neighbouring substance 



