1895.] 



The Act-ion of Heat upon Elhylene. 



403 



Correcting the unsaturated hydrocarbons for change in volume, we 

 obtain uiidecomposed 



The ethylene used contained 9675 per cent, of unsaturated hydro- 

 carbons, therefore the amount decomposed is 



Turning now to the experiments made with the large tube and 

 40 c.c. a minute rate of flow, we find that the percentage of ethylene 

 decomposed was 



an increase of decomposition with the small tube amounting to the 

 following percentages : 



showing that the maximum increase of 34 per cent, rapidly falls with 

 increased length of flow, whilst the ratio of area of heated surface to 

 the passing gas is 43'96/7'85, or 5'6 times as great in -the small tube 

 as in the large, yet only gives an increase of one-third at most in the 

 decomposition. 



2 G 2 



