132 



Capt. Noble and Mr. F. A. Abel. [May 29, 



A comparative examination of the highest, lowest, and mean pro- 

 portions of solid products furnished by the four military powders with 

 which complete series of experiments (with charges ranging in gravi- 

 metric density from 01 to 0*9) were made, elicits various points of 

 interest, for which reference must be made to the complete memoir. 



Before quitting this portion of the subject the authors refer to 

 a statement appended to their memoir, in which they have given the 

 results of the following calculations : — 



(1.) The amount of gaseous products, calculated from the data fur- 

 nished by the analysis of the solid products. 



(2.) The amount of solid products, calculated from the data fur- 

 nished by the analysis of the gaseous products. 



(3.) A comparison between the weights of the elementary sub- 

 stances found in the products of combustion and the weights of the 

 same elements found in the powder prior to ignition. 



(4.) The weight of oxygen contained in the total quantity of hypo- 

 sulphite found. 



An examination of this statement will show how closely accordant 

 the various analyses, as a whole, are. 



A review of the comparison between the weight of oxygen origin- 

 ally in the powder and that found in the products after explosion, 

 appears to show that there is in the latter, on the average, an appre- 

 ciable excess of oxygen. Hence it may pretty fairly be concluded 

 that a portion of the hyposulphite found is due to the oxidation of the 

 monosulphide after removal from the explosion-vessel. 



On the other hand, a reference to those analyses in which hypo- 

 sulphite exists in large proportions shows that, were the whole of the 

 hyposulphite assumed to be formed after the removal of the products 

 from the cylinders, there would exist a large deficiency in oxygen, 

 and very much larger than the existing excess. Hence it may be 

 equally fairly concluded from this line of argument that it is im- 

 possible to attribute to accidental causes the formation of the whole 

 of the hyposulphite, and that a large proportion of it must be looked 

 on either as a primary or secondary product. 



In passing to a consideration of the heat generated by the explosion 

 of gunpowder, the authors point out that, in their first memoir, they 

 themselves called attention to the inconvenience and to the errors likely 

 to arise from the employment of the particular form of apparatus used, 

 and that they were at the outset fully alive to the great advantages, in 

 regard to saving of time and labour, as well as in respect of accuracy, 

 which would result from the use of an apparatus of the kind since 

 employed by them. But, as one of the chief objects of their experi- 

 ments was to ascertain whether the results of the metamorphosis of 

 gunpowder, when fired in considerable quantities and under tensions 

 similar to those developed in the bores of guns, were at all similar to 



