MABERY. — COMPOSITION OF PETROLEUM. 285 



0.1605 grm. of the oil gave 0.1 GOG grm. AgCl. 



Calculated for C T H 13 C1. Found. 



CI 26.77 26.13 



The specific gravity of the chloride at §£ was 0.9332 ; at f£, 0.931 G ; 

 at f 1 ,-,, 0.9231 ; at f^o, 0.9138. The coefficient of expansion for one de- 

 gree calculated from these results is 0.000973. 



A determination of the molecular weight at the freezing point gave 

 the following value: — 



o 



0.9318 grm. of the oil and 19.98 grms. of benzol gave a depression of 

 1°.744. 



Calculated for 7 H 13 C1. Found. 



132.5 131 



The index of refraction at 20° was found to be 1.441, and the molec- 

 ular refraction, 37.57; calculated for C 7 H 13 C1, 37.11. 



These results are sufficient to establish the formula for this hydro- 

 carbon as C 7 H 14 . It is probably dimethylpentamethylene. It differs in 

 its properties from methylhexamethylene, boiling point 99° -100° ; its 

 chloride boils at 147°, while methylhexamethylene chloride boils at 

 141°-142°. 



Metiitlhexamethylexe Chloride, C 7 H 13 C1. 



To ascertain the correct boiling point of heptamethylene, the dis- 

 tillates 95°-l00° were carried through a series of distillations until the 

 greater portion collected at 98°-100°, and this product distilled for the 

 most part at 99°-100°, Bar. 745°. 3, with the mercury column wholly 

 in the vapor. 



The empirical formula of this hydrocarbon has been ascertained in the 

 distillates from various specimens of California oils, by analysis and de- 

 terminations of molecular weight. The boiling point of hexahydrotoluol, 

 prepared by the addition of hydrogen to toluol, was given as 97°. Mark- 

 owuikoff found that the same hydrocarbon separated from Russian 

 petroleum, and also the synthetically prepared heptanaphtene, boiled 

 at 101°. 



For further identification of our product it seemed advisable to study 

 its derivatives. The chlorine derivative was first formed by passing 

 chlorine into the hydrocarbon over water until the greater part was 

 converted into the chloride. This reaction takes place very readily in 



