22 PROCEEDINGS OF THE AMERICAN ACADEMY. 



vania oil has yet to be ascertained. It is conceivable that the differ- 

 ence in the composition of petroleums is due to the different influences 

 to which they have been exposed. Perhaps greater porosity of the 

 reservoir or cover where oils exist under pressure has permitted an 

 escape from certain oils of the more volatile constituents, especially of 

 the series C^Ho^ + o. If this should be demonstrated by more 

 extended observations, it would be reasonable to ex[)ect the same 

 bodies in the Pennsylvania as in the Russian oil, only in smaller 

 quantities of the higher constituents. Referring the sul{)hur in Ohio 

 petroleum to the average composition of the compounds containing it, 

 the crude oil should contain at least five per cent of the sulphur deriv- 

 atives. Evidently such a large proportion of sulphur compounds iu 

 petroleum must exert an important influence on its properties, and we 

 should therefore expect a marked difference between the sulphur 

 petroleums and those which contain only traces of sulphur. 



From a general similarity of Ohio petroleum to the oil from 

 Pennsylvania, so far as it relates to hydrocarbons of the series 

 C„H2„ + 25 it should perhaps be expected that the composition of the 

 latter oil, which has been established beyond question, at least so far 

 as the portions of low boiling points are concerned, should represent 

 also similar portions of the Ohio product. As mentioned above, even 

 a casual examination of the sulphur oils affords abundant evidence 

 that their peculiar properties depend upon other constituents than the 

 hydrocarbons C„H2„ + 2' While these unique constituents may detract 

 from, rather than enhance, the value of the sulj^hur oils for commercial 

 purposes, it is as important for the intelligent guidance of the refiner 

 as it is interesting from a scientific point of view that they be well 

 understood. 



While occupied with the sul|>hur compounds in Ohio petroleum, I 

 was impressed with the complexity in composition manifested by the 

 products of distillation, and with the importance of a thorough exami- 

 nation for all constituents. We therefore began with an endeavor to 

 separate and identify the individual homologues of methane which 

 have been found in Pennsylvania petroleum, including an approximate 

 quantitative determination of all but the more volatile members. 



Hydrocarbons QJT2«-!-2- 



To separate the hydrocarbons of lower boiling points we obtained 

 twenty-five litres of the very first distillate from a three-hundred 

 barrel still. This distillate contained 0.10 per cent of sulphur. 



