1895.] 



The Action of Heat upon Etliylene. 



395 



The apparatus and methods of analysis employed were the same as 

 described in the former paper, with the exception that a platinum tube, 

 14 mm. in diameter and 73*6 cm. long, was used as the decomposing 

 chamber, and that an easily regulated gas combustion furnace was 

 employed as the source of heat. The temperature of the gas in the 

 tube was measured as before, by the Le Chatelier thermo-couple, 

 and every precaution was taken to keep it constant during the 

 experiments. 



The ethylene in each case was prepared by heating a mixture of 

 25 parts, by weight, of alcohol and 150 of strong sulphuric acid, 

 purifying, and storing in a large glass holder. 



The first set of experiments was to ascertain the influence of 

 area of heated surface upon ethylene when passing through a tube 

 heated to the temperature most often employed in the destructive 

 distillation of coal and hydrocarbon oils, and also to find the result 

 of varying the rate at which the gas was passed through the zone of 

 heat. 



Table I. Influence of Rate of Flow and Length of Heated Surface 

 upon the Amount of Ethylene decomposed. Temperature, 900 C. 

 Rate of Flow, 5 c.c. per minute. 



Length of tube beated 1 inch. 6 incbes. 18 inches. 



Volume of gas before heating . . 525 625 625 



after .. 490 653 670 



Analysis of gaseous products. 



Carbon dioxide '75 '50 '75 



Oxygen '50 '25 1 "00 



Unsaturated hydrocarbons 17 -80 10 '75 2 "75 



Carbon monoxide 2-21 1-75 1 '75 



Saturated hydrocarbons by absorp. 11 '25 "I AR Qh 9 '50 \ fin ^ 12 '22 "I c _ . 



byexplos. 35'62/ 4( ' 8 ' 51'15J W> ^ B 53'20/ b ' 



Hydrogen 24-12 22 '75 24 '00 



Nitrogen..' 7 '75 3 '25 4 '33 



On now calculating the percentage for the change in volume, we 

 obtain the following figures : 



Length of tube heated 1 inch. 6 inches. 18 inches 



Unsaturated hydrocarbons 16 '60 11 '25 2 '94 



Saturated hydrocarbons 43 '72 63 '42 70 '13 



Hydrogen 22 '50 23 '75 25 '72 



