126 



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



[May 29, 



tions expressing the chemical metamorphosis undergone by powder, at 

 J east as far as regards its fundamental products. 



3. In directing attention to the determination by the authors of the 

 heat disengaged by the explosion of powder (the results of which 

 were put forward by them with some reserve), MM. Morin and 

 13erthelot regard the figure arrived at as too low, partly because of a 

 (ieficiency in delicacy of the apparatus, and partly because higher 

 figures have been arrived at by M. Tromenec and by MM . Roux and 

 Sarrau. 



In discussing M. Berthelot's views respecting the objections which 

 the authors raise against the acceptance of any chemical equation as 

 giving even a general idea of the metamorphosis which a gunpowder 

 of average composition may be considered to undergo when exploded 

 in a confined space, they disclaim having had any intention to convey 

 the impression, which indeed they consider that their expressions were 

 not calculated to convey, that it was impossible to put into some form 

 of equation a representation of a variety of reactions which, if assumed 

 to take place simultaneously, among different proportions of the 

 powder-constituents, might give approximate expression to the results 

 obtained in any one particular experiment, and might, thus far, afford 

 some approach to a theoretical representation of the metamorphosis of 

 gunpowder. What they desired to point out and lay stress upon was 

 the conclusive proof, which is afforded by the very great variations in 

 composition, of the solid portions more particularly, of the products of 

 explosion of samples of gunpowder presenting only small differences 

 of composition (and even of the products furnished at different times 

 by one and the same sample), that the reactions which occur among 

 the powder-constituents are susceptible of very considerable variations, 

 regarding the causes of which it appears only possible to form con- 

 jectures, and that, consequently, "no value whatever can be attached 

 to any attempt to give a general chemical expression to the meta- 

 morphosis of gunpowder of normal composition." 



Starting with the assumption (which the authors cannot admit to 

 be a correct interpretation of their view) that they regard the varia- 

 tions which occur in the principal products of explosion as "opposed 

 to all general chemical representation of the metamorphosis produced 

 by explosion," M. Berthelot proceeds to argue that the formation of 

 those products, viz., of carbon dioxide, carbon oxide, potassium sul- 

 phate, sulphide and carbonate from a powder of normal composition, is 

 simply and satisfactorily accounted for by assuming the simultaneous 

 occurrence, in variable proportions, of either three or four out of five 

 different theoretical reactions, according as to whether the proportion 

 of sulphate found ii so small that it may be neglected, or amounts to 

 12 or 14 per cent. 



After giving further equations which apply to the extreme results 



