200 



Capt. Noble and F. A. Abel. 



[Mar. 4, 



the removal of the residues from the explosion vessel, and their pre- 

 paration for analysis. 



Distilled water, carefully freed from air by long continued 

 boiling, was syphoned into the vessel when it had cooled after the 

 explosion, and thus no air was ever allowed to come into contact with 

 the solid products. When the vessel was quite filled with water it 

 was closed, and, after having been left at rest for a sufficient time to 

 allow the residue to dissolve completely, the solution was rapidly 

 transferred to bottles which had been freed from oxygen. These, 

 when completely filled with the liquid, were hermetically sealed until 

 the contents were submitted to analysis in accordance with the usual 

 method, when they furnished respectively 4 and 6 per cent, of hypo- 

 sulphite. These results corresponded closely to others obtained by the 

 analysis of seven residues obtained in experiments with P., R.L.Gr., 

 and L.Gr. powders, in which there were no peculiarities assignable as a 

 possible reason why the proportions of hyposulphite should be so 

 much lower, in these cases, than in other experiments carried out 

 with the same powders under as nearly as possible the same con- 

 ditions. 



By the results obtained under the various conditions pointed out in 

 the foregoing, we were forced to the conclusion that the discovery of 

 a small or a larger proportion of hyposulphite by the analysis of the 

 powder residue, obtained as described, is consequent upon some slight 

 variation (apparently not within the operator's control) attending 

 the explosion itself ; but that hyposulphite does exist, though generally 

 not to anything like the extent we were at first led to believe, as 

 a normal and not unimportant product of the explosion of powder in 

 a closed space. 



Some time after the submission of our second memoir to the Royal 

 Society, we received a communication from Professor Debus, which 

 has led us to institute a further series of experiments bearing upon 

 this question of the existence of hyposulphite, and the results we 

 have arrived at have led us so greatly to modify our views on this 

 point, that it is our duty to communicate them without loss of time 

 to the Royal Society. 



As introductory to these, it is necessary to repeat the account, given 

 in our first memoir, of the method pursued by us for determining the 

 proportions of potassium monosulphide and hyposulphite in a powder 

 residue. 



The solution of the residue, prepared by the several methods already 

 described, was separated by filtration, as rapidly as possible, from the 

 insoluble portion, the liquid being collected in a flask in which it was 

 at once brought into contact with pure ignited copper oxide. The 

 solution and oxide were agitated together, from time to time, in the 

 closed flask, the two being allowed to remain together until the liquid 



