MABERY. — ON THE COMPOSITION OF PETROLEUM. 329 



The iudex found, 1.4510, confirmed the same formula: 



Calculated for Cn-IIgj. Found. 



73.65 73.08 



Hydrocarbon Cnlls^, B. P. 177°-179° (30 mm.). 



After the tenth distillation 35 grams collected within these limits with 

 a specific gravity 0.8251 at 20°. After filtration at —10° and treatment 

 with acid the specific gravity was raised to 0.8335. The percentages of 

 carbon and hydrogen by combustion indicated the series C„H.,„. 



0.1501 gram of the oil gave 0.4720 gram COo and 0.1881 gram H.^. 



The molecular weight at the freezing point of benzol determined the 

 formula C17H34. 



1.0880 gram of the oil and 24.9900 grams benzol gave a depression of 

 0°.8U6. 



Calculated for C17H34. Found. 



238 238 



The index of refraction, 1.4545, supported the same formula : 



Calculated for CijHgi. Found. 



78.25 77.50 



A fraction collected at 188°-190° which should contain the next 

 homologous hydrocarbon CisUsc^ but the oil was unfortunately lost by an 

 accident during filtration from the solid. 



Hydrocarbon CioHss, B. P. 198°-202° (30 mm.). 



30 grams of this fraction were collected after the tenth distillation, 

 which gave as its specific gravity at 20°, 0.83 G4. On cooling to —10° 

 and filtration, 16 grams of the filtered oil was obtained with specific 

 gravity 0.8471 at 20°. Determinations of carbon and hydrogen gave 

 percentages which indicated a change from the series CnHon to the series 



C'nH2n_2. 



