584 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Calculated for CjiH^j. Found. 



96.66 96.91 



The molecular weight and molecular refraction show that this dis- 

 tillate is composed of a twenty-one carbon hydrocarbon, and the com- 

 bustion and high specific gravity point to the series C^Han. 



A portion of the oil was cooled to —10°, filtered cold, the solid well 

 pressed in filter paper, and crystallized from ether and alcohol. The 

 ready solubility of these solid hydrocarbons in ether and insolubility in 

 alcohol afford an easy means of purification. The melting point of the 

 purified solid was 40°-41°. 



A combustion gave the following values for carbon and hydrogen : — 



0.1353 grm. of the substance gave 0.4237 grm. CO2 and 0.1778grm. H2O. 



The filtered oil gave as its specific gravity at 20°, 0.8424. The per- 

 centages of carbon and hydrogen were ascertained by a combustion : — 



0.1498 grm. of the oil gave 0.4724 grm. CO2 and 0.1898 grm. H2O. 



Calculated for CjiHjj. Found. 



C 85.70 85.98 



H 14.30 14.08 



Its molecular weight was determined at the freezing point of benzol. 



0.9466 grm. of the oil and 21.01 grms. of benzol gave a depression 

 of 0°.737. 



Calculated for CjiHjj. Found. 



294 299 



docosane, c20h46, and liquid hydrocarbon, c22h44. 

 From Distillate 240°-242°, 50 mm. 



After the thirtieth distillation, 150 grams collected at 240°-242°, 

 which gave as its specific gravity before purification 0.8341. After 

 purification with fuming sulphuric acid its specific gravity was 0.8262. 

 Combustions gave the following percentages of carbon and hydrogen : — 



