1882.] 



Chemical Theory of Gunpowder. 



3G7 



tion produced during the first stage. And because these products are, 

 according to equation 4, nearly in the same relative proportions as 

 they are according to 3, it follows that the distribution of the oxygen 

 of the saltpetre between potassic sulphate, potassic carbonate, and 

 carbonic acid, as required by equation 4, corresponds nearly to the 

 most simple ratios which can exist under the conditions of the experi- 

 ments. 



The oxygen of the potassic carbonate stands to the oxygen of 

 the potassic sulphate and of the carbonic acid, according to equa- 

 tion 3, as 



1:2:2. 



If a mixture of saltpetre, carbon, and sulphur shall produce, by its 

 combustion, the greatest possible amount of heat, and if at the same 

 time the products — potassic sulphate, potassic carbonate, and carbonic 

 acid — shall be formed in such proportions that the heat of formation 

 of one shall stand to the heat produced by each of the other two in the 

 most simple ratio possible, then the combustion must take place 

 according to equation 4. 



The heat developed by the formation of potassic carbonate stands 

 to that furnished by potassic sulphate and carbonic acid respec- 

 tively as 



1 : 2 05, 



and 1 : 1-04. 



if the powder is transformed according to equation 4. 



The relations between the quantities of oxygen in the chief products 

 of combustion and those of the heat produced by their formation are, 

 from a theoretical point of view, of the greatest interest. 



15. Gunpowder, as a rule, contains more carbon and sulphur than 

 is required by equations 3 and 4. 



The carbon left free at the end of the first stage of the combustion 

 now acts on the potassic sulphate, formed during this stage, according 

 to the equation 



4K 2 S0 4 +7C=2K 2 C0 3 + 2K 2 S 2 + 5C0 2 . . . . (6), 



and the free sulphur upon potassic carbonate according to 



4K 2 C0 3 + 7S = K 2 S0 4 + 3K 2 S 2 + 4C0 2 . . . . (5), 



and some of the free carbon reduces carbonic acid to oxide. 



These reactions constitute the second stage of the combustion of 

 gunpowder ; they are endothermic, heat is not evolved but is rendered 

 latent ; they are not of an explosive nature, and, in practice, are prob- 

 ably seldom complete. During the second stage of the combustion 

 the temperature of the products of explosion is diminished and the 

 volume of the gas is increased. 



