232 GUN-COTTON AND GUNPOWDER. 
more surprising. Where the reducing body preponderates, the combustion of 
the carbon is more imperfect. Whereas the gases of sporting powder orly con- 
tain three per cent. of carbonic oxide, the gas from ordnance powder contains 
nearly ten per cent. The quantity of hydrogen and of marsh gas increase in 
the same di.cction, so that the ordnance powder gas contains nearly twenty per 
cent. of combustible gases. Hence it is not surprising that the gases of ordnance 
powder, as wcll as those of gun-cotton, may be ignited, as direct experiment 
showed, by a g!immering piece of wood. 
There might apparently be no difficulty, from the results of these analyses, 
in. arriving at a right composition of powder; yet in this respect practice pre- 
fers its own empirical path. But in any case the results obtained serve as an 
additional proof of the inaccuracy of the view which prevails in many chemical 
text-books and in almost all artillery institutions—that powder must decompose, 
in burning, into sulphide of potassium, carbonic acid, and nitrogen. If practice 
has no other reason for the composition of powder than the possibility that 
these products may occur, it is certainly allowable to attempt to prove experi- 
mentally that the products of combustion, even under the circumstances which 
prevail in practice, can never be formed alone, and that, indeed, one of them— 
sulphide of potassium—in many cases is not formed at all. 
DR. CRAIG’S REMARKS. 
It will be seen from the foregoing that Lieutenant von Karolyi burnt gun- 
cotton under two conditions, and determined for each the composition of the 
resultant gases. In the one case he ignited a small quantity by means of a 
voltaic current in an eudiometre which had been exhausted of air by the 
Torricellian method, and in which, consequently, the cotton burned under very 
small pressure. In the other, an iron cylinder was filled with gun-cotton, 
placed in an exhausted vessel, and ignited in a similar manner, so that the 
combustion went on under pressure until the enclosing tube was broken. 
This increase of pressure was found to give rise to a modification in the com- 
position of the resultant gases; and, for purposes of comparison, the results 
in the two cases may be expressed in chemical symbols, with numbers aflixed, 
which give with suflicient accuracy the relative amounts in volume. 
Burning without | Burning under 
Gas produced. epee ae 
pressure. pressure. 
pee. ee Seas Ae ey Sb. at ee 85 13 
OES ciacoe tote eee Ee Re acid ool ete 220 250 
RO Pee actos Sie oS o's a ath AE OD eld eae oft ind 285 290 
eres tees ho. b=. cckttacmeseeeibetie ss ome assve es 190 210 
Reese ON oS as Cacteece te eeekne x<2 cae ceeee se DO: | 2" a tate 
Giese enaene see bas Be od IES 110 7 
The interesting experiments of Mr. Abel on the combustion of gun-cotton 
in the receiver of an air-pump exhausted to different degrees point to the con- 
clusion that, in burning, gun-cotton is decomposed by the action of heat into 
certain products, among which ay the binoxide and some of the higher oxides 
of nitrogen, and a large quantity of combustible gases. These gaseous pro- 
ducts react on each other with the disappearance of the oxides of nitrogen and 
the production of new compounds if their temperature is maintained above a 
certain point, but if they are allowed to expand into a vacuum as fast as they 
