G2 Professor Ahel [March 21, 



WEEKLY EVENING MEETING, 

 Friday, March 21, 1879. 



The Duke of Northumberland, LL.D. D.CL. Lord Privy Seal, 

 President, in the Chair. 



Professor Abel, C.B. F.E.S. 

 Becent Contributions to the History of Detonating Agents. 



Among the many explosive preparations which have during the last 

 thirty years been proposed as substitutes for gunpowder, on account 

 of greater violence and other special merits claimed for them, not one 

 has yet competed with it successfully as a propelling agent, nor even 

 as a safe and sufficiently reliable explosive agent for use in shells ; 

 for industrial applications and for very important military or naval 

 uses, dependent upon the destructive effects of explosives, it has had, 

 however, to give place, to a very important extent, and in some instances 

 altogether, to preparations of gun-cotton and nitro-glycerine. 



But there appeared little prospect that either gun-cotton or nitro- 

 glycerine, whether used in their most simple condition or in the forms 

 of various preparations, would assume positions of practical impor- 

 tance as explosive agents of reliable, and therefore uniformly efficient, 

 character, until the system of developing their explosive force through 

 the agency of a detonation, instead of through the simple agency of 

 heat, was elaborated. 



Before the first step in this important advance in the application 

 of explosive agents was made by Alfred Nobel, about twelve years ago, 

 the very variable behaviour of such substances as gun-cotton and 

 nitro-glycerine, when exposed to the heat necessary for their ignition 

 under comparatively slight modifications of attendant conditions (e. g. 

 as regards the completeness and strength of confinement or the 

 position of the source of heat with reference to the main mass of the 

 material to be exploded) rendered them uncertain in their action, and 

 at any rate, only applicable under circumstances which confined their 

 usefulness within narrow limits. The employment by Nobel of an 

 initiative detonation, produced by the ignition of small quantities of 

 mercuric fulminate or other powerful detonating substances, strongly 

 confined, for developing the violent explosion, or detonation, of nitro- 

 glycerine, opened a new field for the study of explosive substances, 

 and the first practical fruit was the successful application of plastic 

 preparations of nitro-glycerine and of compact forms of compressed 

 gun-cotton, with simplicity and certainty, to the production of destruc- 



