124 



Capt. Xoble and Mr. F. A. Abel. 



[May 29, 



firing the charge in different spaces, which were given in their first 

 memoir on this subject, and a statement of the mean percentage com- 

 position by volume of the gases and by weight of the solid products 

 furnished by those three powders, together with the highest and 

 lowest proportions in which each product has been obtained with the 

 three descriptions of powder. This table includes the results of ex- 

 amination of the products of explosion of four descriptions of powder 

 differing in many respects from the powders chiefly employed in their 

 researches. The other table gives the complete results of the whole 

 series of analyses made, showing the proportion by weight of each 

 solid and gaseous product, and including the amount of water pre- 

 existent in the various specimens operated on. 



The following abstract of the table first referred to includes the 

 -analytical results of the products furnished by the four special samples 

 of powder, and the highest, lowest, and mean proportions of the 

 several products furnished by the three principal powders used. (See 

 next page.) 



A portion of this memoir is devoted to a discussion of a few points 

 raised in reference to the first memoir of the authors, on fired gun- 

 powder, by General Morin and M. Berthelot, who were appointed by 

 the Academie des Sciences as a Commission to report on that mernoir. 

 These points were specified and discussed by those savants in a joint 

 report, and in two separate memoirs communicated by M. Berthelot 

 to the Academie. 



The principal points to which attention has thus been drawn are as 

 follow : — 



1 . Potassium hyposulphite has been found as one of the products of 

 combustion of gunpowder by every recent investigator. But the 

 question arises : Is this product either wholly or in part primary ? or- 

 is it to be considered as secondary, formed from the primary products 

 during the rapid loss of heat to which they are exposed? or is it, 

 tinally, to be considered only as formed from the sulphide by the ab- 

 sorption of oxygen during the processes of removal from the cylinder 

 and analysis, and therefore to be regarded as an accidental product ? 



2. The authors, from their investigation of the products of explosion 

 in gunpowder in close spaces, conclude that "any attempt to express, 

 even in a complicated chemical equation, the nature of the metamor- 

 phosis which a gunpowder of average composition may be considered 

 to undergo, would only be calculated to convey an erroneous impres- 

 sion as to the simplicity or definite nature of the chemical results and 

 their uniformity under different conditions, while possessing no im- 

 portant bearing upon an elucidation of the theory of the explosion of 

 gunpowder." 



M. Berthelot, in one of his memoirs based upon the authors' results, 

 proposes to represent these results by a system of simultaneous equa- 



