

586 PROCEEDINGS OF THE AMERICAN ACADEMY. 



The quantity of the hydrocarbon was not sufficient for a determina- 

 tion of its molecular weight. 



The filtered oil gave as its specific gravity at 20°, 0.8296, a value 

 somewhat higher than that obtained before filtration. A combustion 

 gave the following percentages of carbon and hydrogen : — 



0.1505 grm. of the oil gave 0.4717 grm. C0 2 and 0.1937 grm. H 2 0. 

 0.1411 grm. of the oil gave 0.4419 grm. C0 2 and 0.1819 grm. H 2 0. 



Calculated for C^H^. Found. 



C 85.70 85.49 85.41 



H 14.30 14.31 14.32 



These proportions correspond to the formula C 22 H 44 , which is supported 

 by the high specific gravity. 



The molecular weight of the filtered oil was also determined : — 



1.0713 grm. of the oil and 19.60 grms. benzol gave a depression of 0°.858. 



Calculated for C 22 H a . Found. 



308 312 



The wide difference in specific gravity between the solid and liquid 

 hydrocarbons at 240°-242°, 50 mm., point to different series. While 

 the percentages of carbon and hydrogen given by analysis could not alone 

 be depended on to prove the different series, the results of combustion 

 with specific gravity are sufficient. The differences in theoretical com- 

 position of the two series are 0.5 of one per cent for carbon and for 

 hydrogen. In combustions conducted under the most favorable condi- 

 tions and with the greatest care, the different series may be shown in 

 well purified materials. But with so many determinations, and the ex- 

 treme care in details of the method, while the percentages obtained are 

 sufficiently close to indicate the series, the results are not in all cases as 

 close to the calculated percentages as should be reached in the greater 

 . precision of a few analyses. 



Tricosane, C 23 H 48 , and Liquid Hydrocarbon, C 23 H 46 . 

 From Distillate 258°-260°, 50 mm. 



After the nineteenth distillation, 175 grams collected at 258° -2 60°, 

 50 mm., for the most part at 260°-261°, which deposited a considerable 

 quantity of solid hydrocarbon on standing. The specific gravity of the 

 unpurified distillate decanted from the solid was as follows : — 



