1G8 



RESEARCHES ON THE VOLATILE HYDROCARBONS 



Formula. (?) 



Cin H 



10 xx 12 



C, 2 H 

 C 14 H 



Cik H 



16 XA 18 



2d Series. (Not completed.) 



Boiling-point. 



68.0 



98.5 



125.1 





Elementary- 

 difference. 



C 2 H 2 



C 2 H 2 

 C 2 H 2 



Difference of 



boiling-point 



found . 



30.5 

 26.6 



Range of Tempera- 

 ture within which the 

 substance would all 



distil. 



57.1 



2 



1.0 



0.6 



28°.6 



Average boiling-point difference = 28°.6 



• 



3. Of Hydrocarbons obtained from CoaUar Naphtha. 



Name of Substance. 



Benzole, 

 Toluole, 

 Xylole, 



Isocumole, 



Formula. 



C I2 H ( 



Cl4 Us 



C,sH 



Boiling-point. 



80.0 

 110.3 



139.8 



169.9 



Elementary 

 difference. 



C 2 TI2 

 C 2 H 2 



Co Ho 



Difference of 



boiling-point 



found. 



30.3 



29.5 

 30.1 



89.9 



Range of Tempera- 

 ture within which the 

 substance would all 



distil. 



o 



0.8 



0.7 

 0.4 



1.0 



Average increment of boiling-point for the addition of C 2 H 2 = 89.9 -r- 3 = 29°.97 



4. Of Oumole from Cmninic Acid, and Cymole from Oil of Cumin. 



Name of Substance. 



Cumole, 

 Cymole, 



Formula. 



Boiling point 



Cis H J2 



Elementary 



difference. 



Difference of 

 boiling-point 



found. 



15L1 



179.6 



C 2 II 



28.5 



Range of Tempera- 

 ture within which the 

 substance would all 



distil. 



I 



o 



3.6 

 1.2 



With only a single exception, the results presented in the above tables point clearly 



common increment for the addition of Co H> in homologous 



to 30° as the 



f 



2. Xi 2 



hydrocarbons. Indeed, leaving out of the calculation the third series from petroleum 



(having the general formula C n H 



hich must remain anomalous, 



and also the 



products from oil of cumin, the average of all the other boiling-point dim 

 29°.T5. The few individual variations f rom the number 30°, rarely exeeedin 



erle 



degree, may reasonably be attributed to errors of the thermometer (especially in case 

 of temperatures above 100°), or in some instances to a want of purity of one of the 

 compared substances j which latter cause I doubt not is the case with the body from 

 petroleum boiling at 37°, as upon this body I had bestowed less labor in fractionin 



than upon most of 



of the 



erne 



volatility and 



quent 



foot 



