1908] 



on Explosive Combustion. 



81 



yield mainly carbonic oxide and hydrogen, without separation of car- 

 bon, mixtures of paraffin and oxygen corresponding to (^J^^n + 2 + 



^ O2 yield carbon, oxides of carbon, methane, hydrogen, and steam, 



all in considerable quantities. Are we then to conclude that there is 

 some peculiarity about the constitution or combustion of an define 

 which induces a preferential burning of its carbon, whilst the corre- 

 sponding paraffin is burnt in an entirely different way ? The following 

 experiment will show that such a view cannot for a moment be enter- 

 tained. 



Experiment III. — I will now fire a bulb containing a mixture of 

 GO per cent, of ethylene and 40 per cent, of oxygen (i.e. 3C2H4 + 

 20.3). xis might be expected, the flame is accompanied by a large 

 deposition of carbon, but what is of greater importance still is the 

 fact that a considerable amount of water is also formed. The full 

 significance of this experiment may be gathered from the following 

 data. 



Original mixture 



PJPl 



Gaseous products CO, = 2-5, CO = 37-2, C,H,, + C„H, = 6-4, CH, 



H2 = 47 • 4 per cent. 



1-45 



6-5, 



Units in original mixture 

 Units in gaseous products 



Difference . 



I think it will be now admitted that such an experiment as this 

 completely destroys the foundations of the theory of the preferential 

 burning of carbon. As I have already stated, the original experi- 

 mental basis of the theory, was the behaviour of an equimolecular 

 mixture of ethylene and oxygen, yet here is proof that on closer 

 examination the behaviour of ethylene is inconsistent with the 

 theory. I would therefore say to those who may be inclined to 

 cavil at my views as to the mechanism of combustion, that what- 

 ever may l3e the final issue of the controversy, this fact, amongst 

 others, must be explained, namely, that whereas a mixture of an ole- 



fine and oxygen corresponding to C^Hg^ f ^^ O2, yields mainly car- 



bonic oxide and hydrogen on explosion, in harmony with the equa- 

 tion — 



Vol. XIX. (No. 102) G 



