1880.] 



Fired Gunpowder. 



199 



of analysis, emanating as it did from one of the highest authorities in 

 experimental research, we considered ourselves fully justified in main- 

 taining that the very considerable variations in the amount of hypo- 

 sulphite found in different analyses, carried ont as nearly as possible 

 nnder like conditions, and the high proportion of sulphide obtained 

 in several of those analyses, afforded substantial proof that accidental 

 oxidation during the collection and analysis of the residues was not 

 sufficient to account for all but the very small quantities of hypo- 

 sulphite, which, in M. Berthelot's view, could have pre-existed in the 

 powder residues. Other facts established by the exhaustive series of 

 experiments detailed in onr first memoir, were referred to by us in 

 our second memoir in support of the above conclnsion (from which we 

 have still no reason whatever to depart). At the same time we de- 

 scribed a series of supplementary experiments which had been instituted 

 by us, with a view to obtain, if possible, further decisive evidence as 

 to the probable proportions of hyposulphite and sulphide actually 

 existing in the residues furnished by the explosion of gunpowder in 

 closed vessels. 



In the first place, the residues obtained by the explosion of charges 

 of R.L.Gr. and pebble powders were submitted to special treatment. 

 Portions of each, consisting exclusively of large masses, were very 

 speedily detached and removed from the explosion vessels, and sealed 

 up in bottles freed from oxygen, having been exposed to the air only 

 for a few seconds. Other portions of the same residues were very 

 finely ground and exposed to the air for 48 hours. As was stated in 

 our recent memoir, the portions of the residues treated in the last- 

 named manner contained very large proportions of hyposulphite 

 (although in one of them there still remained about 3 per cent, of 

 sulphide) while those portions which had been for only a brief period 

 exposed to air (and which presented but small surfaces) were found 

 to contain from 5 to 8'5 per cent, of hyposulphite. As, throughout 

 our entire series of previous experiments, no accidental circumstances 

 had occurred which even distantly approached the special conditions 

 favourable to the oxidation of the sulphide presented in these par- 

 ticular experiments, we considered ourselves fully justified in con- 

 cluding that the non-discovery of any sulphides in the analyses of 

 residues furnished by the fine grain powder in three out of the whole 

 series of experiments, was not due to accident in the manipulations ; 

 and that in those instances, in our several series of experiments, in 

 which large quantities of hyposulphite were found, the greater pro- 

 portion of that substance must have existed before the removal of the 

 residues from the explosion vessel. 



Not suffering the question to rest there, however, we proceeded, in 

 the second place, to adopt new precautions, in two special experi- 

 ments, for guarding against the possible formation of hyposulphite in 



