128 



Capt. Noble and Mr. F. A. Abel. 



[May 29,. 



from the cylinder, especially in some instances when the structure of 

 the residue was favourable to atmospheric action, and when the 

 development of heat afforded proof of the occurrence of such oxida- 

 tion. They point out, on the other hand, that no hyposulphite could 

 be accidentally formed from sulphide during the analytical operations 

 as carried out by them, and they proceed to show that the very con- 

 siderable variations in the amount of hyposulphite, as well as the 

 large amount of sulphide found in several instances, in distinct 

 operations conducted with very great uniformity, afford substantial 

 proof that accidental atmospheric oxidation during the collection and 

 analysis of the residues, is not sufficient to account for all but the very 

 small quantities of hyposulphite which M. Berthelot considers could 

 only have pre-existed in the residue examined by the authors. 



They furthermore direct attention to the following facts given 

 in their first memoir, which appear to have been overlooked by 

 M. Berthelot. 



1. Separate examinations (conducted precisely alike) of the upper 

 and lower portions of some of the residues, showed that considerably 

 larger proportions of hyposulphite existed in the wpjper portions. In 

 one case, quoted by them in their first memoir, the upper portion con- 

 tained 17*14 per [cent, of hyposulphite, while the lower portion only 

 contained 4 - 34 per cent. At the same time there was only a difference 

 of 1'27 per cent, in the proportions of monosulphide existing in the 

 two portions of the residue (6"03 in the upper part and 7"3 in the 

 lower), while there was a very great difference in the amount of free 

 sulphur (4'88 in the upper part and 10"09 in the lower). 



2. One of the small buttons of the fused solid products, of which 

 there was generally one found attached to the firing plug in the 

 cylinder, was examined for sulphide and hyposulphite (it having been 

 detached without fracture and at once sealed up in a small tube). It 

 contained the latter, but none of the former, while the mass of the 

 residue of this particular experiment contained a somewhat consider- 

 able proportion of sulphide. 



3. The production of high proportions of hyposulphite was but 

 little affected by any variations in the circumstances attending the 

 several explosions (i.e., whether the spaces in which the powder was 

 exploded were great or small), excepting that the amount was high in 

 all three cases when the pow^der was exploded in the largest space. 

 The analytical results given in the earlier memoir show abundantly, 

 on the other hand, that a great reduction in the size of grain of the 

 powder used had a great influence upon the production of hypo- 

 sulphite. 



Although the authors consider that the formation of hyposulphite 

 in the solid residue, before the explosion- vessel is opened, and, indeed, 

 to such an amount that it must be regarded as an important product 



