44 MABERY—THE COMPOSITION OF PETROLEUM.  [April3, 
hydrocarbons, paraffine itself is decomposed into hydrocarbons of 
lower molecular weight. But while this view is well supported by 
the facts observed relating to the nature of paraffine, we have not 
been satisfied with less than actual proof by experiment of its 
presence in crude oil, and several lines of work have been carried 
on in this direction. 
Last year we placed several liters of crude petroleum in a large 
flue of the laboratory, with strong draught, and allowed it to evap- 
orate during several weeks. Much the larger portion of the original _ 
oil had evaporated, and the residue was so very thick it would 
scarcely flow. By careful extraction of the oil with ether and 
alcohol we obtained a small amount of solid paraffine, as shown by 
its melting-point and resemblance to ordinary solid paraffine hydro- 
carbons. 
In another line of work, the results of which have not been pub- 
lished, we procured ten gallons of a semi-solid mass of hydro- 
carbons from a refining company at Coreopolis, Pa., that had been 
collected from the sucker rods in pumping oil and had never been 
distilled ; this oil is very heavy, light yellow in color and is used 
for the preparation of commercial cosmolines and vaselines. By 
cooling some of this product and crystallization we were able to 
separate from it a mixture of hydrocarbons closely resembling par- 
affine. A considerable portion of this pasty mass was subjected to 
fractional distillation, and a series of hydrocarbons separated with 
the composition of the series C,H,,,,. The oils separated by 
cooling and pressure gave results on analysis corresponding to 
series poorer in hydrogen. 
We next took up the composition of the mixtures that form the 
vaselines and cosmolines. The refiner makes a sharp distinction 
between crystallizable and uncrystallizable paraffine. But there 
seems to be but one form of solid paraffine hydrocarbons. Vasel- 
ine is simply a very heavy oil saturated with paraffine, and con- 
taining an excess of solid paraffine in the form of an emulsion. 
The oil is composed of the heavy oils of the series C,H,, and 
C,,H,, 42, and the solid bodies members of the series C,H,,4,. The 
so-called scale paraffine of the refiner is solid paraffine containing 
sufficient of the heavy oils to prevent it from assuming a well- 
defined crystalline condition. 
The appearance of the series C,H,, and the series C,H,,_, in 
Pennsylvania petroleum distillates, as shown in a paper published 
