206 



Capt. Noble and F. A. Abel. 



[Mar. 4, 



Lastly, we still think that the following facts, given in our second 

 memoir, must not be overlooked in considering the question of possible 

 occasional existence of considerable proportions of hyposulphite, viz., 

 that " the production of high proportions of hyposulphite was but 

 little affected by any variations in the circumstances attending the 

 several explosives {i.e., whether the space in which the powder was 

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

 all three cases when the powder was exploded in the largest space ; on 

 the other hand, a great reduction in the size of grain of the gun- 

 powder used appeared to have a great influence upon the production 

 •of hyposulphite, as when passing from a very large grain powder 

 (P. or R.L.Gr.) to a fine grain powder (F:G\). Thus, the production 

 of hyposulphite exceeded 20 per cent, (on the solid residue) in only 

 .3 out of 9 experiments with P. powder, in 3 out of 10, with R.L.Gr., 

 and in 7 out of 9 with F.Gr. ; while it was below 10 per cent, in 4 out 

 of 9 experiments with P. powder, in 5 out of 10 with R.Gr.L., and in 

 only 1 out of 9 with F.G-. powder." The experiments made with these 

 several powders followed in no particular order, and no circumstance 

 existed in connexion with them to which these great differences in the 

 results obtained could be ascribed. 



We append a recalculation of the mean results of our three series 

 of analysis, adding the values of the hyposulphite found, as mono- 

 sulphide, to the amount of sulphide actually found, and we hope to be 

 allowed to add to our second memoir a similar recalculation of the 

 whole of our analyses. 



This recalculation develops (as we pointed out in our second 

 memoir must necessarily be the case) a more or less considerable 

 deficiency of oxygen in the total products of explosion ; there is, 

 however, in every instance, also a deficiency of hydrogen, and it may, 

 therefore, be reasonably concluded that the deficiencies in the total 

 quantities of the oxygen and the hydrogen in the powder used, which 

 .are unaccounted for in the products found, on the assumption that 

 variable proportions of the total hyposulphite found actually existed 

 in the residues as sulphide, are properly accounted for by assuming 

 that the missing quantities of these elements actually existed among 

 the products as water, the amount of which it was obviously im- 

 possible to determine. 



In conclusion, we have to state that we considered it right, in con- 

 sequence of the error discovered in the method adopted for the 

 examination for hyposulphite, to repeat the experiments described in 

 our first memoir as having been made by us, with the view of 

 ascertaining whether hyposulphite could exist at temperatures 

 approaching those to which the solid products of explosion were 

 .actually subjected in the explosion vessels in our experiments. 



To test this point we submitted, for between ten minutes and a 



