THE ROYAL ARTILLERY INSTITUTION. 
415 
most important respects, so greatly at variance with the views hitherto adopted 
respecting the general nature of the chemical changes involved in the explosion of 
gunpowder, and consequently, with reference to the several conditions which 
influence the degree of force exerted by the explosion, that all who are interested 
in the considerations embraced in the research of these chemists, will be inclined 
to scrutinise closely the means by which they have arrived at their results before 
accepting them as likely to represent correctly the effects obtained by the employ¬ 
ment of gunpowder in practice.’* 
Their errors lie in their supposing that the products they obtained are 
the same as exist in the gun during the time of maximum effect. The solid 
residue, which forms about two-thirds of the total charge, is mainly carbonate 
and sulphate of potash. Mr. Bloxan# informs me that, from the appearance 
of this residue after deposition, he is decidedly of opinion that it has been 
deposited from the gaseous state. Further on we shall see that Rumford’s 
experiments support this view. We are therefore at liberty to assume with 
Piobert that there are two actions, one during the time of greatest heat and 
pressure, and one afterwards. We may even go further than Piobert, and 
suppose that the solid products are not only in the gaseous state, but to a 
certain extent decomposed by the high temperature, in accordance with 
a chemical law, of which there are numerous examples, such as the 
decomposition of carbonic acid into carbonic oxide and oxygen at a high 
temperature, or of water into hydrogen and oxygen by the heat of the 
electric spark. 
Keeping these considerations in view, I have prepared a formula which 
appears to be a very reasonable one. In the opinion of Professor Bloxain, 
to whom I have submitted it, we know so little of the effects of such 
extremely high temperatures upon the substances remaining after the ex¬ 
plosion of powder, that the supposition is as allowable as any other. It is 
this:— 
English powder, with one-quarter per cent, less nitre, gives an exact 
chemical formula which we may suppose to decompose thus :—■ 
*' 6 (KO,NO s ) + 20 C + 5 S = 20 CO + 5 S0 2 + 6 KO + 6 N. 
The method of calculating the amount of gas produced, with the tem¬ 
perature and resulting pressure, is as follows :— 
Constituents. 
Units of 
heat 
evolved. 
Products. 
Volumes. 
of 23-3 
cub. in. 
Weight 
in 
grains. 
Specific 
heat. 
Units of 
heat required 
to raise 
1° C. 
20 C . 
297720 
20 CO 
40 
280 
•174 
48-72 
5 S . 
176000 
5 S0 2 
10 
160 
•11 
17-6 
6N 
12 
84 
•174 
14-616 
6 (K0,N0 5 ) ... 
... ) 
l 
6KO ' 
282 
•174? 
49-068 
473720 
62 
806 
130 
* Professor of Chemistry, King’s College, London, Advanced Class of Artillery Officers, &c., &c„ 
55 
