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X. Contributions to the History of Explosive Agents . — Second Memoir. 
By F. A. Abel, F.B.S . , Treas. Chem. Soc. 
Eeceived December 1, 1873, — Eead February 5, 1874. 
Since the publication of the experiments on the explosion of gun-cotton and other 
compounds and mixtures by detonation, which are detailed in a memoir submitted by 
me to the Royal Society in March 1869 *, this matter has received considerable prac- 
tical development, and has also been made the subject of further scientific investigation, 
both in England and on the Continent. In continuing my researches into the condi- 
tions to be fulfilled for accomplishing the detonation of explosive substances, I have 
arrived at further results confirmatory of, and additional to, those described in my 
former memoir. I have also been led to pursue experiments bearing upon this 
subject in somewhat new directions ; and I venture to believe that an account of the 
results arrived at may possess some value as tending to throw further light upon the 
behaviour and properties of explosive agents. 
The exceptional behaviour which I have described as being exhibited by certain 
explosive compounds when applied to the development of detonation, in comparison 
with other substances, to which they were not inferior as regards the force and heat 
developed by their explosion, has been confirmed by further experiment. It was stated 
by me that 0'32 grm. (5 grains) of mercuric fulminate, if applied under favour- 
able conditions, suffice to develop the detonation of compressed gun-cotton, that 3 '25 
grms. (50 grains) of chloride of nitrogen appeared to be the minimum amount by 
which detonation of gun-cotton could be developed, that 6’5 grms. (100 grains) of 
iodide of nitrogen failed to produce this result, and that repeated trials with different 
quantities of nitroglycerine ranging up to 31 -2 grms. (1 ounce) did not in any one 
instance result in the detonation of gun-cotton by that substance, although the me- 
chanical force and heat developed by it's explosion were at least fully equal to those 
brought into operation by corresponding quantities of the most violent of the above 
explosive agents. 
The experiments with nitroglycerine have since been considerably extended by me. 
Vessels containing 62 # 4 grms. (2 ounces) and 12T8 grms. (4 ounces) of nitro- 
glycerine have been placed upon disks (weighing 8 ounces) of compressed gun-cotton, 
and the liquid has been exploded by means of a fulminate-fuse. The only effects of 
the violent explosion produced were, in each case, the pulverization and dispersion of 
the mass of gun-cotton, some of the particles being occasionally ignited ; but no 
* Phil. Trans, vol. clix. p. 489. 
MDCCCLXXIV. 2 Y 
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