220 
CAPTAIN NOBLE AND MR, F. A. ABEL ON FIRED GUNPOWDER. 
would have been predicted from the comparatively small proportion borne by the 
oxidising agent to the oxidisable constituents in the mining powder. 
It will be seen presently that the experiments with mining powder presented 
other features of great interest in addition to those elicited by the chemical 
examination of the products of explosion. In concluding our observations on these, 
we should point out that fresh confirmation is afforded by this experiment of the fact 
insisted upon by us, namely, that hyposulphite must be classed among the invariable* 
products of explosion of gunpowder in closed spaces. 
An examination of the three complete series of results obtained by the explosion of 
pebble, It. L. G., and F. G. powders in closed spaces in which their gravimetric 
densities varied from 0’1 to 0'9 per cent, of the space, and which are given in detail 
in Tables I. and II.,t suggests the following observations additional to those included 
in our first memoir, on the nature and relations to each other of the solid products 
furnished by the several powders. 
Comparing the highest, lowest, and mean proportions of the chief solid products 
furnished by the three powders, which differed but little in composition from each 
other, the following points are observed :— 
1. The proportions of potassium carbonate furnished by E, L. G. and by P. powder 
are very similar, while the highest, lowest, and mean results furnished by F. G. are all 
decidedly lower than those from the other two powders. 
2. The mean proportions of sulphate furnished by P. and II. L. G. are not far 
different, though the highest amount furnished by the former is considerably below, 
and the lowest number considerably above the corresponding numbers furnished by 
E. L. G. powder. But the mean and the lowest proportions of sulphate furnished by 
F. G. is very considerably higher than the corresponding numbers obtained with the 
two other powders (the highest amounts obtained with F. G. and E, L. G. being 
identical). 
The generally greater extent to which the sulphur has undergone complete oxidation 
in the case of the F. G. powder is certainly not a result which can be in the least 
ascribable to accidental circumstances attending the experiments, and the fact that it 
corresponds with the generally higher proportions of hyposulphite furnished by this 
powder affords additional support to the view which we maintain, that the production 
of the latter substance, in variable, and sometimes very considerable amounts from 
the powders experimented with, is not to be explained away by ascribing it to accident 
of manipulation. 
3. It will be seen that, whereas the means of the amounts of hyposulphite obtained 
in the analyses of the residues from pebble and E, L. G. powders are almost identical, 
they amount to little more than half that of the mean numbers furnished by the 
* See note at end of this paper 
f See also Tables XII. and XIII. 
