132 COMPOSITION OF AMERICAN PETROLEUM. [Feb. 5, 



limits, leaving the series CnH.^+g, as representing the main body of 

 Pennsylvania petroleum within these limits. The individual repre- 

 sentatives of this series, when properly collected by fractional distil- 

 lation and purification, include a decane at 163°-! 64°, normal de- 

 cane at i73°-i74°, undecane at i95°-i96°, and undecane at 214°- 

 216°. From Canadian petroleum a hydrocarbon collects at 196°- 

 197° whose percentage composition and molecular weight, as well as 

 the composition of the monochlor-derivative, corresponds to the 

 formula CnHaa, and another at 2i4°-2i6°, with the formula C12H24. 

 The composition of all these hydrocarbons was ascertained by anal- 

 ysis, molecular weight determinations, analysis of chlorine deriva- 

 tives, and molecular weights of the chlorine derivatives. 



The impression that the higher portions of Pennsylvania oil are 

 composed of naphthenes was perhaps not wholly without a reasonable 

 foundation. After finding hexahydroisoxylol in Russian oil Beil- 

 stein and Kurbatoff identified the same body in Pennsylvania oil. 

 Since no further attempts were then made to ascertain the composi- 

 tion of the higher portions, it was natural to infer that the results of 

 Warren leading to the series C^Han should be best explained by 

 assuming that his bodies were naphthenes. After the discovery of 

 thenaphthene series in Russian oil by Markownikoff, this belief was 

 strengthened by the erroneous assertions of Hoefer and other 

 anthors of German publications on petroleum that Markownikoff 

 had established the naphthene series in Pennsylvania oil. A critical 

 comparison of the specific gravity of Warren's hydrocarbons 

 with those of Markownikoff without further work would have sug- 

 gested doubts as to the presence of naphthenes in Pennsylvania oil 

 at least below 216°. 



It has long been an open question with oil men as to whether 

 Ohio and Canadian petroleum is identical with Pennsylvania oil as 

 regards the principal constituents. With respect to the portions 

 distilling between 150° and 216°, this question has now been 

 answered. The observed differences in the properties of distillates 

 within these limits before purification concern, as has been shown, 

 specific gravity and percentage composition. Before purification, 

 however carefully the distillates have been separated by fractional 

 distillation, analytical values correspond fairly well with the series 

 CnHan- After removal of the aromatic hydrocarbons the specific 

 gravity is much reduced, and in the Pennsylvania distillates it cor- 

 responds to the specific gravity of the same hydrocarbons synthet- 



