104 Prof. V. B. Lewes. [Feb. 1, 



and that these compounds, by further polymerisation and interac- 

 tions amongst themselves, of the kind studied by Berthelot and 

 Carnelley,* give rise to a large number of others. As the temperature 

 rises, the methane formed in the primary action splits up into acetyl- 

 ene and hydrogen, 



2CH 4 = C 2 H,+3H a ; 



and when the temperature has reached the decomposing point of the 

 acetylene, which varies with the degree of dilution, polymerisation 

 takes place no longer, but the acetylene splits up directly into carbon 

 and hydrogen, and all the products formed at lower temperatures 

 doing the same thing, the final reaction is 



= C,+2H,. 



An attempt was now made to see how far analytical results would 

 quantitatively bear out the inferences deduced from the foregoing 

 experiments. 



To do this, the method adopted was as follows : The whole ap- 

 paratus was filled with ethylene. The platinum tube and condensing 

 tube were weighed, and the amount of ethylene in the gas holder 

 measured. The platinum tube was heated to the required tempera- 

 ture, and the gas aspirated through it at a uniform rate of 4*2 c.c. 

 per minute. When sufficient gas had passed through (about 250 c.c.) 

 the stopcocks were turned off, and the amount of gas left in the 

 holder measured. The amount of water displaced from the aspirator 

 was also measured, and in this manner the change in volume was 

 determined. The tube was again weighed, and the gain in weight 

 noted. The platinum tube was also weighed, and then slowly heated 

 to dull redness in a stream of hydrogen, in order to drive off any oil 

 that might have been condensed in it, and again weighed. The tube 

 was now heated to bright redness in a stream of oxygen, in order to 

 burn off carbon, and again weighed. The sample tube was closed, 

 and the contents analysed ; the acetylene in the absorption bottles 

 was also determined in the usual way. 



Ethylene was first heated to 700800 C., but no acetylene was 

 formed, no alteration in volume took place, and the gas seemed 

 unacted upon. 



The temperature was then raised to 800 900 C., and the following 

 results obtained. 



Oil .............. 0-0131 gram per 100 c.c. gas. 



Heavy oil ........ 0'0055 . 



Carbon .......... Nil 



Decrease in volume 100 to 89 

 Acetylene formed . 0'057 per cent. 



* ' Chem. Soc. Journ.,' vol. 37, p. 701. 



