DR. H. DEBUS ON THE CHEMICAL THEORY OE GUNPOWDER. 
569 
from four to five times greater in the products of the mining powder than in those of 
the service powder. The gases of the former are combustible, those of the latter are not. 
The potassic sulphocyanate has been formed by the metamorphosis of Curtis and 
Harvey’s powder in quantities ten times as large as were observed amongst the 
products of the Waltham Abbey mixtures. It is well known that potassic carbonate, 
sulphur and charcoal, at a •white heat, in an atmosphere containing nitrogen, will 
produce potassic sulphocyanate. The amount of potassic sulphate, as might be 
expected, present among the products of the mining powder is almost nil, and the 
source of the by-products of the combustion of gunpowder is laid bare. 
If we discard the by-products, we obtain for the combustion of a powder with an 
excess of carbon the equation : 
16KN0 3 + 28C+8S=4K a C0 3 +4K a S a +12C0 a + 12CO + 8N 2 
or more simply : 
4KN0 s +7C+2S=K 2 C0 3 +K 3 S 2 -f3C0 3 +3C0+2N 3 
which represents with sufficient exactness the reactions between saltpetre, carbon, and 
sulphur, when an excess of carbon is present and is introduced in the form of charcoal. 
Carbonic acid and oxide have been found by experiment to be a little higher, in 
consequence of the action of the oxygen of the charcoal, potassic carbonate a little 
lower, in consequence of the formation of some potassic sulphocyanate, than is required 
by the foregoing equation. 
It is also worthy of notice that in spite of the presence of free carbon, more than 
13 mols. of C0 2 have remained undecomposed. 
From the remarks of the preceding pages it follows that during the complete 
metamorphosis of powder, the reactions between the constituents of saltpetre, the 
carbon of the charcoal, and sulphur, take place according to equations (III.), (IV.), (V.), 
(VI.), and (VII.), and that by means of equation (VIII.) the products, namely, potassic 
carbonate, potassic sulphate, potassic disulphide, carbonic acid and nitrogen, which are 
formed during the combustion of a weight of powder containing x mols. of saltpetre, 
y atoms of carbon, and z atoms of sulphur, can be calculated in a satisfactory manner. 
It now remains to calculate, by means of the same equation, the quantities of heat, 
gas, and energy which powders of various composition are able to produce. 
For this purpose we assume that we have to deal with mixtures of saltpetre, sulphur, 
and pure carbon , and that the combustion is complete, viz.: that it runs to the end of 
the second stage. If we conceive that during the transformation of the powder no 
carbonic oxide is formed, we should, as a consequence, have a considerable simplifica¬ 
tion of equation (VIII.) without influencing much the calculated amounts of gas and 
heat. 
The conversion of the carbonic oxide to carbonic acid could only take place at the 
expense of the oxygen in the potassic sulphate; if it occurred according to the equation 
4 D 2 
