MABERY. — OX THE COMPOSITION OF PETROLEUM. 325 



The oils filtered from these fractions were very thick aiul viscous. De- 

 termiuatioiis of the specific gravity of the unpurified fractions at 20^ 

 gave values essentially higher than the corresponding fractions from 

 Pennsylvania oil : 



After removal of the solid hydrocarbon each fraction was thoroughly 

 purified with sulphuric acid, agitating first with common concentrated 

 acid and then with fuming acid, until the acid was nearly colorless. The 

 heavier distillates were first dissolved in light gasoline, for they formed 

 alone with acid an emulsion from which the oil did not readily separate. 

 For complete removal of the acid the oil was finally washed with sodium 

 hydrate, then dried first over calcium chloride and finally over sodium. 

 If the oil remains unchanged after standing some time over sodium it is 

 very well purified. 



In the present state of our knowledge concerning the series of hydro- 

 carbons poorer in hydrogen than the series CnIT,o+2' definite names can- 

 not be assigned to the members of these series. It is probable that the 

 series CnlTon is composed of the methylene hydrocarbons, perhaps with 

 complex side chains. The series still poorer in hydrogen may contain 

 two or more methylene rings, but as yet there is no evidence as to what 

 form these bodies may have. 



Hyduocarbon C12H24, B. P. 211°-213°. 



In a former paper* the fraction 212^-214° atmospheric pressure was 

 shown by analysis and further identification to be dodecane, CioHog, and 

 its specific gravity was found to be 0.7727 at 20°. This hydrocarbon 

 was separated with others from a specimen of crude oil obtained from a 

 well at Find lay, Ohio. Its specific gravity and composition corresponded 

 to that of dodecane, which was separated from Pennsylvania petroleum. 



The fraction 211°-213° now under examination gave as its specific 

 gravity after thorough purification with sulphuric acid, as described 

 above, 0.7970. A combustion gave percentages of carbon and hydrogen 

 corresponding to the series C„H2n • 



* These Proceedings, 32, l.J4. 



