362 Dr. H. Debus. [Feb. 23, 



the residues according to Btmsen and Schischkoff's method ; and as it 

 is decomposed at 225° 0., it cannot be considered as one of the chief 

 products of the combustion of gunpowder. 



3. With regard to the products, potassic carbonate, potassic sul- 

 phate, potassic disulphide, carbonic acid, carbonic oxide, and nitrogen, 

 the following problems have to be solved : — 



(a.) To determine the reactions which cause the formation of these 

 substances and the order in which they succeed each other, and to 

 represent the complete combustion of gunpowder by one chemical 

 equation. 



(b.) To calculate from the known composition of a given weight of 

 powder the volume of gas and the amount of heat generated during 

 its combustion, and to ascertain the relative energies of powders of 

 different composition. 



The solution of each of these problems is described in the paper. 



4. Noble and Abel* describe the quantitative relations of the 

 products of combustion of a given weight of powder of known com- 

 position in the following words : — 



" (a.) The proportions in which the several constituents of solid 

 powder residue are formed are quite as much affected by slight acci- 

 dental variations in the conditions which attend the explosion of one 

 and the same powder in different experiments, as by decided differences 

 in the composition as well as in the size of grain of different powders. 



" (b.) The variations in the composition of the products of explosion 

 furnished in close chambers by one and the same powder under diffe- 

 rent conditions, as regards pressure, and by two powders of similar 

 composition under the same conditions, as regards pressure, are so 

 considerable, that no value whatever can be attached to any attempt 

 to give a general chemical expression to the metamorphosis of gun- 

 powder of normal composition. 



" (c.) Any attempt to express, even in a comparatively complicated 

 chemical equation, the nature of the metamorphosis which a gun- 

 powder of average composition may be considered to undergo, when 

 exploded in a confined space, would therefore only be calculated to 

 convey an erroneous impression as to the simplicity or the definite 

 nature of the chemical results and their uniformity under different 

 conditions, while it would, in reality, possess no important bearing 

 upon an elucidation of the theory of explosion of gunpowder.f 



" (d.) Very small-grain powder, such as F.G. and B-.F.Gr., furnish 

 decidedly smaller proportions of gaseons products than a large- grain 

 powder, R.L.G. : while the latter again furnishes somewhat smaller 

 proportions than a still larger powder, P, though the difference 

 between the gaseous products of these two powders is comparatively 

 inconsiderable." 



* "Phil. Trans.," clxv (1875), p. 137. 



f Ibid., p. 85. 



