160 Mr. F. A. Abel on the [Feb. 5, 



III. " Contributions to the History of Explosive Agents." Second 

 Memoir. By F. A. ABEL, F.R.S., Treas. C.S. Received 



December 1, 1873. 



(Abstract.) 



The researches detailed in this memoir are in continuation of those 

 described in the Memoir on Explosive Agents, published in 1869*, and 

 relate chiefly to the investigation of the conditions to be fulfilled for 

 accomplishing the detonation of explosive substances, and of the circum- 

 stances and results which attend the transmission of detonation. 



The exceptional behaviour exhibited by certain explosive compounds 

 with respect to their power of inducing the detonation of other sub- 

 stances by their explosion, which was demonstrated and discussed in 

 the preceding memoir, has been confirmed by further experiments. The 

 susceptibility of some substances to detonation, through the agency of 

 certain compounds, and their remarkable inertness when subjected to the 

 detonation of others, which at any rate do not rank lower as regards the 

 mechanical force and heat developed by their explosion, led the author to 

 suggest that a similarity in character, or synchronism, of the vibrations 

 developed by the explosion of particular substances, might operate in 

 favouring the detonation of one such substance by the initial detonation 

 of a small quantity of another, while, in the absence of such synchronism, 

 a much more powerful initiative detonation, or the application of much 

 greater force, would be needed to effect the detonation of the material 

 operated upon. This view, which has been favourably entertained by 

 many, as affording a reasonable explanation of the apparently anomalous 

 results referred to, appears to have received support from the results of 

 experiments recently instituted by Champion and Pelletf, with iodide of 

 nitrogen and some other explosive compounds, which indicated that the 

 explosion of certain sensitive substances could be accomplished only by 

 vibrations of a particular pitch, and by which they also demonstrated that 

 particular explosions affected certain sensitive flames which were un- 

 affected by others, unless the volume of the explosion was proportionately 

 much increased. 



Some few experiments were made by Champion and Pellet on the 

 transmission of detonation to iodide of nitrogen through considerable 

 spaces, by means of tubes, and some experiments of a purely practical 

 character have also been instituted by Captain Trauzl, on the transmission 

 of detonation to cartridges of dynamite, separated by spaces, in iron 

 tubes, by the explosion of a charge of the material placed in one extremity 

 of the tube. It appeared to the author that a systematic investigation of 

 the transmission of detonation through the agency of tubes, with the 

 employment of explosive agents less highly susceptible and more uniform 



* Phil. Trans. 1869, vol. clix. p. 489. 



t Comptes Eendus, vol. Ixxv. pp."210 & 712. 



