MABERY. 



CONSTITUENTS OF PETROLEUM. 



171 



by assuming, which is evidently true, that Pelouze and Cahours over- 

 looked the aromatic i)ydrocarboiis. It does not appear in their reference 

 to American petroleum whether they really operated on distillates from 

 Pennsylvania oil ; but, on the other hand, their specific gravity determi- 

 nations are not widely different from those of distillates from Canadian 

 oil to which occasional reference is made in their publications. 



Pennsylvania Petroleum. 



Fraction. 

 C. F. M. 

 Unpurified. Purified. 



163°-164° 



163°-164° 



p. & c. 



1«2° 



Specific Gravity. 

 C. F. M. P. & C. 



Series. 



196°-197° 



196°-197° 



0.7684 (20°) 

 0.7479 (20°) 



0.7673 (20°) 

 0.7581 (20°) 



196°-200° 



214° -216° 0.7745(20°) 



214° -216° 0.7684(20°) 



216° -218° 



0.7780 



0.796 



Canadian Petroleum. 



Fraction 

 Unpurified. 



163°-164° 

 196°-197° 

 214° -216° 



Fraction 

 Purified. 



163°-164° 

 196°-197° 

 214° -216° 



C„H2„ 



0.757(15°) CnR2n+2 

 C„H2„ 



C„H2„+2 

 C„n2„+2 



C„H2,j 



^v n 2n+2 



C. F. M. 



0.7785 

 0.7582 

 0.7889 

 0.7729 

 0.7947 

 0.7851 



If the results of Pelouze and Cahours were really obtained in distil- 

 lates from Canadian petroleum, as seems probable, especially since 

 Pennsylvania distillates do not yield such high values, the speoific gravity 

 determinations in their lower distillates agree fairly well with mine in 

 the purified Canadian hydrocarbons. 



The results of Warren, on the other hand, are consistent in giving num- 

 bers that account both in specific gravity and in percentage composition 

 for the complex mixture that crude petroleum distillates are known to be. 

 "While Warren made no attempts to purify his distillates, they were ob- 

 tained in a course of fractional separations far exceeding in efficiency 

 those of other experimenters. It is interesting to observe in the following 



