MABERY CONSTITUENTS OF PETROLEUM. 149 



Calculated for CuHj,. Found. 



C 84.51 ' 84.57 



H 15.49 15.73 



Another quantity of the crude distillate was heated on the steam bath 

 during several hours with fuming sulphuric acid, occasionally shaking the 

 acid with the oil, boiled with sodium, distilled, and dried for analysis : — 



0.1519 gram of the oil gave 0.4715 gram COo, and 0.2085 gram H._jO. 



C 84.67 



H 15.26 



The specific gravity of this product was the same as before, 0.7514. 

 In a determination of the molecular weight of the hydrocarbon purified 

 by the mixture of nitric and sulphuric acids, tin and hydrochloric acid, 

 fuming sulphuric acid and sodium, Mr. Hudson obtained 142 ; required 

 for CjqHoo, 142. The fuming sulphuric acid solution separated from the 

 oil was neutralized with baric carbonate filtered and evaporated nearly to 

 dryness. On cooling, a barium salt separated in needles, which were 

 very sparingly soluble in cold water. The air-dried salt was anhydrous, 

 and it gave, by ignition with sulphuric acid, 25.46 per cent of barium. 

 Hexahydrocymo^, requires 23.8 jjer cent of barium, and iso-cymol 24. 3. 

 The first hydrocarbon boils at 171°-172°, m-cymol at 174°-176°, p-cymol 

 at 172°-173°, and pseudo-cymol at 169°. By fuming sulphuric acid at 

 least the iso-cymol if present in petroleum should be extracted, and it is 

 probable that this barium salt was an impure compound of cymolsulphonic 

 acid. That the decane boiling at 174° is the principal constituent of 

 Ohio petroleum at this point, and that it contains a considerable propor- 

 tion of aromatic hydrocarbons, has received ample proof. As to the 

 precise form of the aromatic hydrocarbons, the quantity of material it has 

 been expedient to manipulate in purifying the decane was not sufficient 

 to demonstrate. It would evidently be impossible to separate these 

 bodies from decane in any course of distillation, and it would require a 

 large quantity of the crude distillate, although not so thoroughly distilled 

 as the one prepared in this examination. 



In still further evidence as to the formula of this hydrocarbon, the 

 chlorine derivatives were prepared by the action of chlorine on a por- 

 tion purified with the mixture of nitric and sulphuric acids and sodium. 

 83 grams of the hydrocarbon was allowed to absorb 30 grams of 

 chlorine, the theoretical quantity for the mono derivative being 20 

 grams. As an illustration of the readiness with which substitution 



