34 PROCEEDINGS OF THE AMERICAN ACADEMY. 



importance to justify the necessary expenditure of time and effort. 

 The higher fractions have been quite thoroughly distilled entirely in 

 vacuo to avoid decomposition so far as possible, and these products, 

 as well as the residue above 350° of the first vacuum distillate, are 

 reserved for later study. 



Aromatic Hydrocarbons. 



Series C„H2„_s. 



So far as I am aware no attempts have hitherto been made to sepa- 

 rate the aromatic hydrocarbons from the Ohio sulphur oil. In Ameri- 

 can petroleum Pelouze and Cahours found, as already mentioned, no 

 appreciable quantities, but Schorlemmer recognized the presence of 

 benzol and toluol. Beilstein and Kurbatoff were the first to discover 

 the aromatic hydrocarbons in the oil from Baku, and hexahydroisoxy- 

 lol in Pennsylvania petroleum. 



Benzol. 



After the sixth distillation of the products from the original quan- 

 tity of crude oil, twenty-five grams collected at 77°-79°, 35 grams at 

 79°-8r, and 20 grams at 81°-83°. In each of these fractions the 

 quantity of benzol was determined by heating carefully for some time 

 a weighed quantity of the fraction with a mixture of nitric and sul- 

 phuric acids, distilling off the portion not affected by the acid mix- 

 ture, and weighing it and the residual nitrobenzol. The fraction 77°- 

 79° gave by this method 3 per cent of benzol ; the fraction 79°-81°, 

 15 per cent; and the fraction 81°-83°, 5.8 per cent. The fraction 

 75°-76° and 85°-86°, when treated in the same manner, left scarcely 

 any residual product after distillation, and after reduction with tin 

 and hydrochloric acid not a trace of color was visible in applying the 

 exceedingly delicate furfurol reaction for aniline. Calculating from 

 these numbers, the quantity of benzol in the 41.5 kilos of crude oil 

 taken, it amounts to 7.16 grams or 0.017 per cent, which represents 

 approximately the quantity of benzol in the crude oil. 



Toluol. 



The fractions collected between 107° and 113°, after the sixth distil- 

 lation under a Hempel column, were examined for toluol by treating a 

 weighed quantity of the oil with nitric and sulphuric acids, keeping 

 the solution cold. After some time crystals of dinitrotoluol sepa- 

 rated, and when the hydrocarbons not affected by the acid were 



