MABERY. — SULPHUR PETROLEUMS. 3 



tions with higher boiling points have the composition represented 

 by the general formula C„H2„ + 2 was shown to be erroneous by 

 the results of Warren, which excluded members of this series 

 above 151°. 



The presence of aromatic hydrocai'bons in American petroleum was 

 first recognized by Schorlemraer in 1865. Pelouze and Cahours had 

 previously stated that American petroleum contained no aromatic 

 hydrocarbons, but Schorleramer collected a distillate from Canadian 

 petroleum below 150°, and upon treating it with nitric acid and reduc- 

 ing with tin and hydrochloric acid, after distillation he obtained an oil 

 with an odor of aniline that gave, with bleaching powder, the rosani- 

 line reaction. The portion distilling between 150° and 170° gave a 

 mixture of solid and liquid nitro-products, and the solid portion proved 

 to be trinitrocumol. Benzol and its homologues were also found by 

 Schorlemmer in Pennsylvania petroleum, in Galician petroleum by 

 Freund* and others, and in Hanover petroleum by Bussenius and 

 Einstuck.f In Galician petroleum Pawlewski$ found two per cent of 

 aromatic hydrocarbons, chiefly benzol and paraxylol, the latter never 

 having previously been recognized in any petroleum. In the fraction 

 170°-190° from American kerosene, Engler § discovered pseudocumol 

 and mesitylene by the formation of nitro-com pounds, and calculating 

 the weight of crude oil corresponding to the weight of kerosene taken, 

 it was estimated that these constituents are contained in crude Penn- 

 sylvania oil to the extent of 0. 2 per cent. These hydrocarbons were 

 also found in German, Galician, Italian, and Russian petroleum, in the 

 latter to the extent of 0.1 per cent. According to the results of Beil- 

 stein and KurbatoflT, || the petroleum of the Central Caucasus has an 

 essentially different composition from that of the deposits on the coast 

 of the Caspian Sea. Oil obtained from the region of Zarskige 

 Kolodzy, in the precinct of Tiflis in the Central Caucasus, proved to 

 contain small amounts of benzol and toluol, but to consist jirincipally, 

 like the Pennsylvania petroleum, of the series C^,H2„+2. Pentane, 

 hexane, and heptane were identified. The oil from Baku on the 

 coast contains the series C„H2„ + 2 in smaller quantity, and Beilstein 

 and KurbatofF found no trace of the aromatic hydrocarbons C„H2„_s, 

 but the principal constituents are members of the series C„H2„. 



* Ann Chem. Pharm., CXV. 19. t Ibid., CXIIL 151. 



t Ber. der deutsch. chem. Gesellsch., 1885, p. 1915. 



§ Ibid., 1885, p. 2234. 



II Ibid., 1880, p. 1818 ; 1881, p. 1620. 



