MABERY. — THE COMPOSITION OF PETROLEUM. 569 



In determining the boiling points of these hydrocarbons under at- 

 mospheric pressure, 70 grams of the fraction 124°-126° distilled as 

 follows, under 7 GO mm. and with the mercury column all within the 

 vapor : — 



224°-225° 225°-226° 226° -227° 227°-228° 228°-229° 

 Grams, 4 28 26 3 3 



Colored residue, 6 



The portions between 225° and 227° collected almost entirely between 

 225° .5 and 226°.5. 



The fraction 142°-143° nearly all distilled at 237°-238° atmospheric 

 pressure, the fraction 158°-159° at 256°-257°, the fraction 173°-174° at 

 274°-275°, the fraction 188°-189° at 288°-289°, and the fraction 198°- 

 199° at 300°-301°. The hydrocarbon dodecane C12H26 was identified 

 in the fraction 214°-216°.* 



Tridecane, CjsH 



28' 



The next homologue, tridecane, was sought for in the series of distil- 

 lates that collected between 215° and 235°. After carrying these 

 fractions eight times through a Hempel bead column a larger portion, 

 200 grams, collected at 221°-222°. This portion was distilled twenty- 

 four times, when 70 grams collected, as shown above. The specific 

 gravity of the distillate before further treatment was 0.7866, and after 

 thorough agitation with fuming sulphuric acid, 0.7834. A combustion 

 gave the following values for carbon and hydrogen : — 



0.1506 grm. of the oil gave 0.4690 grm. CO2 and 0.2028 grm. H2O. 



Calculated for CijHjg. Found. 



C 84.78 84.94 



H 15.22 14.96 



The molecular weight of this oil as determined by the Beckman method 

 at the freezing point of benzol, in the hands of different workers, corre- 

 sponded to that of C13H2S. 



distillation of Russian petroleum, air accidently admitted caused such a violent 

 explosion ftiat the thermometer was sent violently across the room and broken 

 against the wall. 



* These Proceedings, XXXII. 138. 



