and of Combustion of Acetylene, Ethylene and Methane. 357 



mutes. 



Temperature. 



16 



3-559 



19 



3*544 



22 



3-530 



28 



3-517 



The experimental result is 8348° : subtracting this number 

 from the thermal effect of the acetylene taken, which is 9768°, 

 we have 1420° required to dissociate 1*18 gram of methane and 

 for 16 grams 19,300 c at constant volume. 



Experiment 18. — Methane 1*431 gram, acetylene 5*467 grams 

 and hydrogen and nitrogen 0*063 gram. The gas after the 

 explosion contained no acetylene, but gave a little carbon 

 dioxide when burned. Apparently some methane was not 

 decomposed. The jacket and room were 0*7°-according to the 

 differential thermometer. 



Water and water equivalent of 

 calorimeter, 3252 grams. 



Minutes. 



Temperature. 







0*36 



3 



0-36 



6 



0-36 



9 



3*28 



12 



3*273 



15 



3260 



18 



3-245 



21 



3-230 



Temperature interval, 



3-273—0-36 + 0*023 = 2*936' 



The result calculated as before is 18,700°. 



The mean of the two results with methane is 19,000 c volume 

 constant and 18,420° pressure constant required to dissociate 

 methane. Thomsen's value of the formation of methane at 

 constant volume is 21,170°. Calculated from Berthellot's data 

 it is 21,500°. 



