io8 CHEMICAL PROPERTIES AND COMPOSITION 



ever, need not be considered on account of involatility of 

 their products. Of the non-metals which alone need be 

 considered, the following mixtures rank first : 



(H 2 .0) = 6 9 , (H.C1) = 28, (H.F) = 37 , (C.0 a ) = 97 . 



Actually these include two known explosive mixtures, viz. 

 oxygen and hydrogen, and chlorine and hydrogen. A 

 mixture of fluorine and hydrogen, on the other hand, passes 

 of its own accord into hydrofluoric acid, while carbon and 

 oxygen are not miscible. 



The other factor conditioning practical applicability 

 initial, solid, or liquid state is wanting in the four pre- 

 ceding cases, but may be arrived at by liquefying the 

 gases ; this can be accomplished in the case of carbon and 

 oxygen by mixing finely-divided carbon with liquid air. 

 This yields an actually available explosive 1 . 



Three elements. By suitably combining two conditions, 

 strain in linkages actually existing, and formation of new 

 linkages with strong affinity, the effectiveness of explosive 

 mixtures may be increased ; this may be done by choosing 

 three elements, A, B, and (7, such that, e. g. the compound 

 of A and B is decomposed with a large evolution of heat, 

 whilst that of A or B with C is formed with a large evolu- 

 tion of heat. Let us consider the possibilities of this with 

 the aid of the former data. 



Of cases in which G combines with one of the elements 

 A and B with a large evolution of heat, we find 



2 N 3 H + i O 2 = 3 N 2 + H 2 O, W = 69 + 2 x 62 = 193. 



Of cases in which C combines with both the elements 

 A and B with a large evolution of heat, we find 



CS 2 + 30 2 = CO 2 + 3SO 2 ,, W = 97 + 2x71 + 22 =. 261, 

 C 2 H 2 + fO 2 = 2C0 2 + H 2 0, W = 2x97 + 69 + 53 = 316. 



1 Bujard, Leitfaden der Pyrotechnik, 1899, p. 189. 



