570 PROCEEDINGS OF THE AMERICAN ACADEMY. 



I. 1.1209 grm. of the oil and 36.3043 grms. benzol gave a depression 

 of 0°.82. 

 II. 1.2502 grm. of the oil and 33.3631 grms. benzol gave a depression 

 of 1°.015. 

 III. 1.496 grm. of the oil and 32.9131 grms. benzol gave a depression 

 of 1°.205. 



Calculated for Found. 



CiaUjs- !• II. in. 



184 184.5 181 184.9 



In still further confirmation of the formula of tridecane, the index of 

 refraction was determined, and its molecular refraction calculated. The 

 index was found to be 1.4354 at 20*^, and the molecular refraction as 

 follows : — 



Calculated for CuHja* Found. 



61.94 61.44 



Monochlortridecane, C13H27CI. — In the preparation of the chlorine de- 

 rivative of tridecane, chlorine was allowed to act on the hydrocarbon in 

 screened sunlight, over water. With care to avoid an excess of chlorine, 

 the product consisted for the most part of the monochloride. It was 

 fractioned in vacuo under 12 mm. several times until considerable of the 

 oil collected at 135^-140°. This fraction gave as its specific gravity at 

 20°, 0.8973. A determination of chlorine gave a percentage required 

 for the monochloride : — 



0.1920 grm. of the oil gave 0.1273 grm. AgCl. 



Required for CijHjjCl. Found. 



CI 16.23 16.39 



The molecular weight as determined at the freezing point of benzol 

 corresponded to the same formula : — 



0.4585 grm. of the oil and 18.35 grms. benzol gave a depression of 0°.568. 



Calculated for C13H27CI. Found. 



218.5 216 



A determination of the index of refraction confirmed the same formula; 

 the index as determined was 1.451, corresponding to the molecular 

 refraction : — , 



Calculated. Found. 



65.71 66.67 



