MABEUY. — ON THE COMPOSITION OF PETROLEUM. 349 



nitrogen, sulphur, and oxygen compounds. Then tlie breaking down in 

 series begins with loss of hydrogen, through the asphaltic hydrocarbons, 

 until finally coke is reached, which forms a considerable proportion of 

 the products of refining. 



V. THE SOLID TAIIAFFINE HYDROCARBONS THAT COLLECT IN 

 CERTAIN OIL WELLS IN PENNSYLVANIA. 



In attempting to determine the series of hydrocarbons, and members of 

 the series that form the solid constituents of Pennsylvania petroleum, it 

 seemed of interest to examine the semi-solid product that collects in con- 

 siderable quantites in some of the Pennsylvania wells, especially at 

 Coreopolis, Pa. The Petrolatum Company collects large quantities of 

 this pasty substance from their wells and from it manufacture various 

 preparations such as vaseline and cosmoline. The crude product is ob- 

 tained in the form of a light-yellow pasty mass, from which it is impos- 

 sible to separate a solid by pressure in filter paper or by filtration. Jt 

 evidently consists of an emulsion of the high boiling oils with, the solid 

 hydrocarbons which no doubt are in part dissolved in the oily constitu- 

 ents. 



Having obtained several gallons of this substance through the kind- 

 ness of the Coreopolis Petrolatum Company in October, 1898, I under- 

 took an examination of it with the principal object of proving the 

 presence of solid hydrocarbons, and identifying their composition as to 

 the series and molecidar formulas, for comparison with the solid hydro- 

 carbons which I have separated from Pennsylvania crude oil and from 

 commercial parafRne. These semi-solid emulsions have no doubt been 

 formed by evaporation of the lighter constituents of petroleum, and the 

 solid hydrocarbons are therefore what were contained in the original 

 petroleum. It also afforded an opportunity to confirm the presence of 

 the solid constituents of paratfine in crude petroleum, a question con- 

 cerning which a doubt is often expressed by refiners. 



The specimen received was in the form of a thick paste, with a spe- 

 cific gravity at 60° of 0.8345. In beginning the distillation, 9380 grams 

 were distilled in a porcelain still under a tension of 50 mm. and the dis- 

 tillates collected in the following quantities : 



