MABERY. — CONSTITUENTS OF PETROLEUM. ' 125 



required, since the boiling points invariably decline many degrees in 

 subsequent distillations. 



The refinery distillate employed was taken at 48° -50° Baume, having 

 a specific gravity 0.7892 at 20°. It was very nearly colorless and gave no 

 odor of decomposition. Forty-five litres of this distillate was fractioued 

 within limits of 10°, 5°, 2°, and for a long time within 1°. It gradually 

 collected in heaps, as described by Warren, but the prolonged distillation 

 was necessary to separate higher and lower constituents from the mixtures 

 between. 



Concerning the impression that Pennsylvania petroleum has the same 

 composition within tiiese limits as the Russian oil, which is based in part 

 on the results of Warren suggesting the series C„H„, and in part on the 

 erroneous statements of Hofer, that Markownikofl: found the same series 

 in Pennsylvania that he had reported in Russian oil, it may be stated 

 once for all that this identity is clearly excluded by the great difference 

 in specific gravity of the corresponding distillates, without reference to the 

 ditferences in percentage composition. These differences in composition 

 are indicated at the outset by the great differences in specific gravity of 

 crude distillates at 16°, as shown by Markownikoff and Oglobine.* 



Baku. American. 



150°-200° 0.786 0.757 



200°-250° 0.824 0.788 



250°-320° 0.861 0.809 



The same differences appear between the individual constituents : t — 



Baku Naphtenes. B.P. Specific Gravity. 



Dekanaphtene CioHoq 160^-162° 0.795 (0°) 



Endekanaphtene C^^^^ 180°-18o° 0.8119 (0°) 



Dodekanaphtene CioHj^ 196°-197° 0.8055 (14°) 



And the series C„H2„ of Warren, purified only by distillation and boil- 

 ing with sodium : t — 



B.P. Specific Gravity at 0°. 



Kutylene CioHgo 174°.9 0.7703 



Margarylene C11H22 19o°.8 0.7822 



Laurylene C12H24 216°.2 0.7905 



* Ber. der deutsch. chem. Gesellsch., 1883, p. 1873. 



t Ibid., p. 1877. 



t Proc. Amer. Acad., XXVII. 15. 



