368 



Dr. H. Debus. 



[Feb. 23, 



16. The quantitative relations between the constituents of gun- 

 powder and the chief products of combustion at the end of the second 

 stage can be expressed by one equation . 



If x, y, and z be positive numbers and a represents how many 

 molecules of carbonic oxide are formed by the complete combustion of 

 a weight of powder containing x molecules of saltpetre, y atoms of 

 carbon, and z atoms of sulphur, we have 



zKNO 3 +#0+zS= 2-V[^+8i/-16^-4^](K 2 C0 3 ) 

 + it[20x—16y + 4? + 8a] (K 2 SOJ 

 -f^[ - 10o5 + 8y + 12* - 4a] (K 3 So) 

 + TV[-^ + 207/ + 16.-24a](CO 2 ) 

 + aCO 



, • • (8), 



as the general equation of the complete combustion of gunpowder. 



By means of this equation the chief products of combustion — 

 potassic carbonate, potassic sulphate, potassic disulphide, and car- 

 bonic acid — can be calculated from that portion of a given weight of 

 powder which transforms itself into these products. 



The correctness of the equation is proved by the agreement of the 

 calculated numbers with those observed by Bunsen and Schischkoff, 

 Linck, and Karolyi in their experiments on the explosion of gun- 

 powder, and also with the corrected mean numbers derived from 

 Noble and Abel's investigation. 



17. The total volume of gas developed by the combustion of a 

 given weight of powder, if calculated according to equation (8), is 

 not affected to more than from one to two per cent, if we put a=0, 

 and in doing so we gain a considerable simplification of the equation. 

 If V represents the volume of gas evolved by the combustion of a 

 quantity of powder containing 16 molecules of saltpetre, y atoms of 

 carbon, and z atoms of sulphur, and W the units of heat developed 

 by the same weight of powder, we have, on the assumption that 

 « = 0, 



v ii w ' 



W=1000[1827-154-16-925y-8788«] . . . (10). 



The volume of gas becomes greater, and the amount of heat 

 diminishes, when y and z are increased, and vice versa. 



Quantities of saltpetre, carbon, and sulphur represented by the 

 symbols 



I6KNO3 + 8C + 8S 

 produce the greatest amount of heat and smallest amount of gas, and 

 such as correspond to — 



16KN0 3 + 24C + 16S, 



