CAPTAIN NOBLE AND MR. F. A. ABEL ON FIRED GUNPOWDER, 
217 
variation of only 1 ‘27 per cent, in the sulphate in different parts of the residue, and 
that in the top and bottom portions the amounts found in the unground and ground 
parts were almost identical, so that the proportion of sulphate was in no way affected 
by the prolonged exposure of the finely-ground residue to air. In the pebble powder 
experiment the sulphate varied in the different parts to the extent of 2 "82 per cent., 
and the higher proportions happened to exist in the ground parts of this residue ; but 
the differences can scarcely be considered sufficiently important to ascribe them to any 
other cause than a little variation in the composition of different parts of this residue. 
Some of the later of our experiments with R. L. G. powder given in the first 
memoir furnished products which, when calculated upon the results of analysis made 
at the commencement of these researches, of a sample of the powder taken from the 
upper part of the contents of the barrel, presented greater discrepancies in some 
points than was the case with some of the earlier products. It was, therefore, con¬ 
sidered desirable to repeat the analysis of this powder, operating upon a sample taken 
from the lower part of the barrel. The results of the two analyses are as follows :— 
Components, per cent. 
It. L. Gr. powder. 
From upper part of 
barrel. 
From lower part of 
barrel. 
Saltpetre. 
Potassium sulphate . 
Sulphur. 
f Carbon . 
Charcoal < Hydrogen . 
] Oxygen . . 
fAsh, &c. . 
W ater . 
74-95 
0-15 
10-27 
10-860 
I 13.50 
1-99 f L6 0 ~ 
0-25 J 
111 
74-430 
0133 
10-093 
12-3980 
0-401 1 , , 
1-272 f 14 ' 280 
0-215 J 
1-058 
The foregoing numbers, which are in each case the means of two very concordant 
analyses, present sufficient differences to establish a small but decided variation in the 
composition of this powder, of which, be it remembered, very considerable quantities 
were employed in the course of the series of experiments. It appeared to us, therefore, 
that we were warranted in calculating the earlier results obtained with this powder 
(produced in 10 to 40 per cent, space) upon the composition as represented by the 
first analysis, and in recalculating the later ones furnished by the lower part of the 
contents of the barrel upon the analysis of the sample taken from that part of the 
powder. 
In completing these researches it appeared to us of interest to include two other 
descriptions of gunpowder in our series of experiments, one of them a representative 
of the sporting powder class, the other representing the higher qualities of blasting or 
mining powder, which are well known to differ very materially in composition from 
MDCCCLXXX. 2 F 
