MABERY. — CONSTITUENTS OF PETROLEUM. 157 



zation aud the formation of heavier oils in these unsaturated bodies after 

 they have been separated and allowed to stand as long as two years. As 

 fuither evidence that these unstable bodies are the cause of the color, 

 after tliey have been removed, the purified oils remain colorless perma- 

 nently. The higher specific gravity observed in the first vacuum distil- 

 late from Canadian crude petroleum is still retained in the single degree 

 fractions, however long the fractional distillation is continued. But 

 although these portions are heavier than the distillates from Pennsyl- 

 vania and Ohio oils, they are so much lighter than the naphtenes that 

 the latter bodies cannot be present in any considerable quantity. In 

 general the ready and abundant formation of nitro derivatives and sul- 

 phonic acids is sufficient evidence that the greater specific gravity is due, 

 for the most part at least, to the aromatic constituents. It is quite prob- 

 able that naphtenes are present in small amounts, and that they are 

 accountable, as has been suggested, for the extreme difficulty in removing 

 the last traces of the less hydrogenized constituents by fuming sulphuric 

 acid, even after vigorous treatment several times repeated. In some 

 instances, nitric aud sulphuric acids have given nitro products that have 

 required very long and vigorous boiling with tin and hydrochloric acid 

 for complete reduction, or an equivalent treatment with sodium. Occa- 

 sionally the reduction with tin and acid has caused the separation of a 

 heavy red oil insoluble in the acid, consequently not an amine. 



Decane, C10H20, 163°-164°. 



The composition of the principal distillates from Canadian petroleum 

 below 150° was found to be represented by the series C„H2„+2- Above 

 this point the distillates were small to 158°, but between this point and 

 162° larger amounts collected and remained persistently at 159°-160° 

 (730 mm.). After treatment with fuming sulphuric acid, a portion of this 

 distillate was still further fractioned until 75 grams distilled at 163°-164° 

 under 760 mm., and with the mercury column all in the vapor. In the 

 crude distillate before treatment with the acid, carbon and hydrogen were 

 determined, with no other purification than drying over sodium. No less 

 efficient means of desiccation removes the water sufficiently for analysis. 

 But since a reddish flocculent precipitate separates when any of these dis- 

 tillates stand with sodium, evidently the percentages of carbon and hydro- 

 gen in the crude distillates cannot be accurately expressed by the results 

 of combustion. The precipitation is doubtless caused in part by sulphur 

 compovTuds which are not wholly removed by alcoholic mercuric chloride, 

 although it is observed when the quantity of sulphur is very small. 



