210 CAPTAIN" NOBLE AND MR. F. A. ABEL ON FIRED GUNPOWDER. 
shall conclusively prove'"' to be formed in very notable quantities before the sobd residue 
can have undergone alteration from external causes. 
It will be seen from the foregoing outline of M. Berthelot’s theoretical explanation 
of the chemical changes involved in the metamorphosis of gunpowder, that the 
simplest form of expression which he can give to the formation of the products of 
explosion consists in the incorporation of nine or ten distinct reactions occurring 
simultaneously, but in very variable proportions, which have to be supplemented by 
three or four other chemical equations, by which the formation, during the process of 
cooling, of certain products believed to be secondary, is explained. Now, although 
such speculations as the above are unquestionably interesting, and, it may be added, of 
a nature which must occur to those who desire to give some kind of definite explana¬ 
tion, for purposes of elementary instruction, of the chemical changes involved in the 
explosion of powder, we fail to see that beyond this they do more than afford the 
strongest confirmation of the correctness of our conclusion, that “ no value whatever 
can be attached to any attempt to give a general chemical expression to the meta¬ 
morphosis of a gunpowder of normal composition.' 
With regard to the potassium hyposulphite which is included hi our statement of 
the composition of the solid products of explosion, we have to submit the following 
considerations. 
In the analytical results furnished by the solid residues, as detailed hi our first 
memoir, the hyposulphite ranged in amount from 3 to 35 per cent.; and on comparing 
the results of different analyses, it is observed that hi most histances the proportion 
of monosulphide was small when the hyposulphite was large in amount, and in a few 
instances—all of them F. G. powder-residues—in which the proportion of the latter 
was very high, there was no sulphide at all. 
Being fully alive to the possibility of the existence of potassium polysulphide in the 
solid residue giving rise to the production of some hyposulphite through the agency 
of atmospheric oxygen, great precautions were taken, especially in the later experi¬ 
ments, in collecting and preserving the residue and in submitting it to treatment for 
analysis, to guard against this possible source of error. 
In the first place, it should be mentioned that the residue consisted in nearly all 
cases of fused, very hard masses, collected at the bottom of the explosion vessel, the 
sides of which were, moreover, generally covered with very thin films. The action of 
atmospheric oxygen upon the fused solid could only be superficial, but would vary in 
extent with the amount of surface of the residue exposed to the air during removal 
from the explosion apparatus or subsequent exposure. The latter was avoided as 
much as possible, as the residues were transferred at once, as they were detached from 
the surfaces of the explosion-vessel, into small bottles, in which they were carefully 
sealed up. It was only in one or two instances that, before opening the bottles, an 
* See note at end of this memoir. 
