MABERY. — SULPHUR PETROLEUMS. 35 



removed by distillation, there remained a heavy oil which consisted of 

 the liquid orthouitrotoluol and crystalline dinitrotoluol. The latter 

 soon solidified, and after crystallization from alcohol it was identified 

 by its melting point, 71°. The loss in weight by the removal of toluol 

 in the fraction 107°-109° amounted to 1.14 per cent, in the fraction 

 109°-lll''to 13.07 per cent, and in the fraction 111°-113° to 2.8 

 per cent. The total weight of the first fraction was 50 grams, of 

 the second 80 grams, and of the third 65 grams. These fractions, 

 therefore, contained altogether 12.85 grams, which corresponds to 0.03 

 per cent of toluol in the 41.5 kilos of crude oil taken. As in the 

 case of benzol, evidently the percentage of toluol is expressed only 

 approximately by these results. After longer distillation the fraction 

 114°-115° was treated in a similar manner, but after treatment with 

 nitric and sulphuric acids, and with tin and hydrochloric acid, the pro- 

 duct which remained in considerable quantity after distillation did not 

 dissolve in hydrochloric acid, and it gave no trace of color when heated 

 wich ferric chloride or with mercuric chloride. The insolubility in 

 acids excludes in this fraction any appreciable quantity of hexahydro- 

 isoxylol which is contained in the higher portions. The oily product 

 of the nitration must therefore be derived from another series, perhaps 

 from an unsaturated hydrocarbon C„H2„ ; it will receive further 

 attention. 



Xylols. 



In the first allusion to the presence of the aromatic hydrocarbons in 

 petroleum, by De La Rue and Miiller,* who found in the Rangoon oil 

 benzol, toluol, metaxylol, and cnmol, there is no evidence that the 

 isomeric forms of xylol were discovered in that petroleum. Except 

 paraxylol, which Pawlewski found in Galician petroleum and Engler 

 in Pennsylvania petroleum, and metaxylol, which is generally found, 

 it does not appear that the isomeric xylols have elsewhere been recog- 

 nized in petroleum. 



Between 136° and 142° in our distillates, at intervals of one degree 

 we collected 205 grams, of which the greater portion distilled at 

 137°-138°, 139°-140°, and 141°-143°. After prolonged distillation 

 these fractions collected in increased quantities at these points ; they 

 were readily acted upon by nitric acid, forming nitre compounds or 

 oxidation products, according to the form of the reaction. 



To prove the presence of paraxylol in fraction 137°-138°, a portion 

 was treated with a mixture of nitric and sulphuric acids, at first in the 



* Proc. Roy. Soc, 1856, p. 221. 



