1908] 



on Explosive Comhiistion. 



83 



Table II.— Experiments on Inflammation in 

 Sealed Glass Bulbs. 



precedence of all other chemical phenomeua in flames. This is pro- 

 bably true of the propagation of flame through explosive mixtures of 

 hydrocarbons and oxygen. In the special case of a stream of a hydro- 

 carbon burning in air, partial decomposition may occur in the inner- 

 most regions of the flame, where the supply of oxygen is very limited, 

 before combustion begins. But, in general, whenever the hydrocarbon 

 and oxygen are brought together at high temperatures, their mutual 

 affinities will prove superior to any disruptive forces wliich would 

 otherwise break down the hydrocarbon. It is probably not so much 

 the original hydrocarbon as its hydroxylated molecule which decom- 

 poses in flames ; the sudden increase in the internal energy of the 

 hydrocarbon molecule, consequent upon its initial association with 

 oxygen, would render the resulting hydroxylated molecule extremely 

 unstable, and, in default of its immediate further oxidation, it would 

 speedily decompose. The explosive combustion of ethylene may, 

 therefore, be represented by the following scheme — 





 H..C : CH., 



HO . CH : CH., - 



/CoH/+H„0^ \ 

 20 + H., + H,0 f 



HO . CH CH . OH 



2CHoO = 2C0 + 2H., 



In a sufficient supply of oxygen, the transition from the original 

 hydrocarbon to the dihydroxy state is probably so rapid that no 

 breaking down of the ethylenic structure occurs in passing through 

 the initial momhydroxy stage. Indeed^ it is conceivable that under 



