Hogal |instttuti0n of (Bxtai HBritatn. 



WEEKLY EVENING MEETING, 



Friday, January 18, 1907. 



Sir James Crichton-Browne, M.D. LL.D. F.R.S., Treasurer 

 and Vict-President, in the Chair. 



Sir Andrew Noble, Bart., K.C.B. D.Sc. F.R.S. i¥.RJ. 



Fifty Years of Explosives. 



I propose in my lecture to give a short account of the changes 

 which have taken place in propellants during the last fifty years : 

 1S56 being the year when, during my voyage to South Africa, my 

 attention was first called to the curious discrepancies between the 

 views of the distinguished men who had written upon the motive 

 force and pressure of gunpowder ; and ever after that year I deter- 

 mined to do my best to solve the difficulties which surrounded the 

 question. 



Fortune has been kind to me in enabling me to carry out my 

 wish, for few men, either when in the Service or since I left it, have 

 been placed in a better position for carrying out the difficult and 

 somewhat dangerous investigations I had at heart. 



During these fifty years, besides various experiments as to explo- 

 sives other than propellants, and modifications to propellants, I have 

 comjjletely examined no fewer than eighteen different propellants, 

 determining, for most of them, the changes in transformation which 

 take place when the explosive is fired under very various pressures. 



The composition of these various explosives was approximately as 

 follows : — 



Older Explosives, 



KN03 



s 

 c 



H,0 . 



F. G. 

 W. A. 



•7391 

 •1002 

 •1459 



•0148 



Spanish 



C. &H. 



No. 6 



■7559 

 •1242 

 ■1134 

 •0065 



■7468 

 ■1037 

 ■1378 

 ■0117 



Mining 



•6192 

 •1506 

 •2141 

 •0161 



Amide 



•40 KNO3 



•38 (NHJNO3 

 •22 C 



Vol. XVIII. (No. 101) 



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