DR. H. DEBUS ON THE CHEMICAL THEORY OF GUNPOWDER. 
573 
Heat of formation of 1 mol. K 2 C0 3 =279530* 
„ „ „ K 3 S0 4 —344640+ 
„ „ » KoS, =108000j 
„ „ „ C0 3 = 97000§ 
„ „ „ KNOg =11948011 
Hence we obtain for the heat of combustion, W 
[A® “h 2“8 2 /— iHhG 279530+ [-§§05 —-Jf y + -gV 2 ! 344640 
+[ +- 2 - 8 t/ -+- *|*] 108000 -J-[— ^&x ~b If y ~b irfhl 97000 
—xX 119480 = W ; or if 05=16, 
W=1000[1827T54 —16*925?/—8’788z].(X.) 
That is to say, a mixture of 16 mols. of saltpetre, y atoms of carbon, and 2 atoms of 
sulphur, will, by its complete transformation according to equation (VIII.), produce 
W units of heat. 
An error attaches to W in consequence of the assumed non-formation of carbonic 
oxide. 
The quantity of this substance produced by the Waltham Abbey powders is greater 
than that formed by other mixtures, but as the error attaching to W in the case of the 
English service powders does not amount to more than 2‘6 per cent, of the total heat, 
an error smaller than the usual errors of observation, it may be neglected for the 
sake of the great simplification of the formula. 
It is perhaps desirable again to call attention to the condition that the equations 
(IX.) and (X.) apply only to mixtures which contain their constituents in such 
proportions that they can completely transform themselves according to equation 
(VIII.). Mining powders are excluded. 
The charcoal of gunpowder is, however, not pure carbon, but contains also hydrogen, 
oxygen, and water. 
The high temperature generated by the explosion causes probably the dissociation 
of these elements, and if, as in Noble and Abel’s experiments, all the carbon is 
oxidised at the expense of the oxygen of the saltpetre, the oxygen of the charcoal 
will reunite with hydrogen and form water. 
The heat absorbed by the decomposition of the charcoal is not known. A portion 
of the hydrogen unites with nitrogen, carbon, and sulphur respectively, forming 
ammonia, marsh gas, and sulphuretted hydrogen. The total heat which is either 
liberated or absorbed by all these secondary reactions, appears, however, to be a small 
* J. Thomsen, ‘ Bericlite der deutscten CEemisdhen GesellscEaft in Berlin,’ Bd. xii., p. 2031. 
t Ibid., p. 2032; Bd. xiii., p. 961. 
+ Sabatier, Comptes Rendns, tom. xc., 1557-1560 ; Cbem. Soc. Journal, 1880, p, 689. 
§ J. Thomsen, ‘ Bericlite der deutschen Chemiscben Gesellscbfift in Berlin,’ Bd. xiii,, p. 1329. 
|| Ibid., p. 500. 
