350 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Distillation of these fractions was continued within 10°, 5°, and 2°, 

 until after the sixth distillation larger quantities collected at the follow- 

 ing temperatures : 



242°-244° 2G8°-270° 280°-282° 308°-310° 328°-330° 

 340°-342° 352°-3d4 ° 368°-370° 382°-384° 



Since the distillates below 268° showed by their thin pasty condition 

 that they contained only small proportion of solid hydrocarbon, no 

 attempts were made to separate their constituents. The fraction 272°- 

 274° gave as its specific gravity at 20'^ 0.8116. A combustion gave the 

 fallowing percentages of carbon and hydrogen : 



0.1600 gram of the substance gave 0.5058 gram COo and 0.1963 

 gram H2O. 



Calculated for CorJIu. Found 



86.21 86.22 



13.79 13.73 



This fraction, therefore, consisted mainly of a hydrocarbon of the 

 series CnH2n_2, and the same will appear in the higher fractions to be 

 described. 



On cooling the distillates with salt and ice, and attempting to separate 

 the solid by filtration under pressure, scarcely any of the solid remained 

 on the filter, so complete was the emulsion. But on trying the solubility 

 in ether and alcohol, such a wide difference was observed between the 

 crystalline and amorphous solid, it aflPorded an easy means of separa- 

 tion. 



The distillate 272°-274^, 30 mm., was therefore dissolved in a suitable 

 mixture of ether and alcohol cooled with salt and ice and filtered cold. 

 The solid collected was pressed and the crystallization repeated, which 

 gave a perfectly white crystalline hydrocarbon, melting point 50°— 51°. 

 It gave as its specific gravity at 60°, 0.7900. Determinations of carbon 

 and hydrogen gave percentages required for the series C„IT.2,i_|_2- 



0.1516 gram of the substance gave 0.4728 gram CO., and 0.1973 

 gram II 2O. 



Calculated for Tetracosane, C24njo. Found. 



C 85.21 85.06 



H 14.79 14.56 



