MABERY. — THE COMPOSITION OP PETROLEUM. 567 



In September, 1896, I set out to ascertain the composition of the 

 principal hydrocarbons in Pennsylvania petroleum above 216° so far as 

 they can be separated by distillation on a laboratory scale. Through the 

 courtesy of the Standard Oil Company, I procured a barrel of crude oil 

 from Oil City and this material has been used to separate the hydro- 

 carbons that will be described in this paper. That this oil was an 

 approximately average specimen of Pennsylvania petroleum, appears 

 from its properties. A determination of the specific gravity of the crude 

 oil at 20° gave 0.8095. A combustion of the oil dried over sodium 

 gave the following percentages of carbon and hydrogen : Carbon, 85.80 ; 

 Hydrogen, 14.04. Eight hundred grams distilled in the ordinary way in 

 the following proportions : — 



50°-150° 150° -200° 200°-250° 250° -300° +300° 

 166 88 83 100 337 



Fifty-six kilos of the crude oil was distilled in quantities of 10 litres each 

 in a porcelain still, collecting under atmospheric pressure to 200°, and 

 within limits of 10° under a vacuum of 50 mm. to 300°, then within 

 limits of 5°, and finally within limits of 2°. After eight distillations the 

 following proportions collected: — 



124°-126° 136°-138° 156°-158° 174°-176° 188°-199° 

 Grams, 125 145 240 205 240 



199°-201° 210°-212° 226°-228° 242°-244° 

 225 335 150 130 



Since the weights of these fractions represent all that came from the 

 original crude oil, it is possible to gain a very general idea of the pro- 

 portion of the hydrocarbons which are contained in the crude oil. But 

 such estimation must be only approximate from the fact that any dis- 

 tillation however thorough gives only an approximate separation, and a 

 considerable portion of any hydrocarbon must be contained in the in- 

 termediate distillates. 



The percentages of the weights are as follows : — 



Ci3H 28 C 14 rl 30 Ci 5 H 32 C 16 H 34 L 17 H 3(5 



124°-126° 136°-138° 156°-158° 174°-176° 188°-199° 



0.22 0.26 0.43 0.37 0.43 per. cent. 



Ci 8 H 38 C 19 H 40 C 20 H 42 ^2i"44 



199°-201° 210°-212° 230°-232° 242°-244° 



0.40 0.60 0.27 0.23 per. cent 



