1904.] The Retardation of Combustion by Oxygen. 87 



3. It is to be supposed that the more complex hydrocarbons are, 

 to a large extent, resolved into simpler thermoschists prior to oxida- 

 tion, e.g. t 



The change may extend even to the formation of carbon, when 

 a relatively small proportion of oxygen is present. In high tem- 

 perature changes (explosions), such thermoschisms probably play an 

 all-important part. 



4. The precise manner in which oxygen is introduced into the 

 hydrocarbon molecule is a matter of some interest. If oxygen 

 molecules were directly active as wholes and the actual, immediate 

 and sole cause of the oxidation, there would seem to be no reason 

 why the dihydroxy-derivative should not be directly produced rather 

 than the monhydroxy : the observation made by Bone and Stockings, 

 that ethyl alcohol is producible from ethane, therefore, is of crucial 

 importance. But, on general grounds, regarding the change as 

 electrolytic in character, it is probable that the electrolyte, i.e., 

 conducting water, is the immediate source of the oxygen ; and that 

 the oxygen molecule* plays the part of depolariser. From the same 

 point of view, it appears probable that the water molecules contribute 

 hydroxyl rather than oxygen. The process may be formulated as 

 involving the conjugation of hydrocarbon (probably through its 

 carbon) with water (acting primarily as the catalyst or associating 

 agent) and oxygen, thus : 



H 3 C OHH CH 3 .OH HO 



H + OHH + 6 " HOH + HO 



5. According to the view here advocated, carbon dioxide is neces- 

 sarily a later product of change than the monoxide in fact, the final 

 product. It is to be supposed that, in its formation from the 

 monoxide, the latter is first converted into formic acid. On this 

 assumption, it is easy to understand that the presence of so large a 

 proportion of water is required in order that/ the explosive wave may 

 attain to its greatest velocity, as the affinity of water for carbon 

 monoxide is relatively slight and the reversible change one which 

 takes place mainly in the direction : 



HCO(OH) ^ CO + OH 2 . 



* The need of distinctive names for oxygen-stuff or atomic oxygen and of the 

 molecular oxygen we handle is very obvious in discussing such a point as this. 



