1879.] 



Researches on Explosives. 



131 



any of the other powders experimented with, as well as from those 

 used by the recent experimenters referred to in the first memoir. 

 The proportion of saltpetre was about 11 per cent, lower than in the 

 military powders, while the proportions of charcoal and sulphur were 

 higher by about one-half. The composition of the former was similar 

 to that of the pebble powder charcoal. The carbonic oxide produced 

 from this powder was double the highest amount furnished by any of 

 the other powders, while the carbonic anhydride, which in the three 

 series of experiments ranged from 45 to 53 per cent., amounted only 

 to 32 per cent., the two gases existing in about equal proportions. 

 Marsh-gas and hydrogen were present in unusually high proportions, 

 and the sulphuretted hydrogen amounted to 7 per cent., being nearly 

 double the highest proportion found in all the other experiments. 

 The solid residue presented very interesting points of difference. The 

 potassium carbonate was, as might have been anticipated, compara- 

 tively small in amount (though some of the experiments with F.G. 

 powder gave similar results in this respect), but there was only 0'5 

 per cent, of sulphate formed, while the monosulphide amounted to 

 33 per cent. Federow's experiments are the only ones in which so 

 high a percentage of sulphide is recorded ; and among the several 

 experiments with R.L.G. powder, in which only small proportions of 

 sulphate were formed, there was only one residue in which the free 

 sulphur was as high in amount as that formed in the mining powder- 

 residue. The hyposulphite amounted to nearly C per cent. — 2 per 

 cent, more than was furnished by the sporting powder under precisely 

 similar conditions of experiment, and double the smallest amount 

 formed in any of the series of experiments cond acted with the very 

 special precautions which were applied in dealing with the residue 

 of the powder under discussion. The ammonium sesqui- carbonate was 

 considerably higher in amount than in any other experiments, and the 

 potassium sulphocyanide amounted to 3 per cent., or about five times 

 the amount found in any other experiment excepting that of Link. 

 Lastly, there was a much more considerable amount of residual char- 

 coal in this experiment than in any other. 



The very distinctive peculiarities shown by the composition of the 

 solid and gaseous products of this powder are generally such as would 

 have been predicted from the comparatively small proportion borne by 

 the oxidising agent to the oxidisable constituents in the mining powder. 



The experiments made with mining powder presented other features 

 of great interest in addition to those elicited by the chemical examina- 

 tion of the products of explosion. In concluding their observations 

 on these, the authors point out that fresh confirmation is afforded by 

 this experiment of the fact that hyposulphite must be classed among 

 the invariable and more important products of explosion of gunpowder 

 in closed spaces. 



K 2 



