MABERY. — CONSTITUENTS OF PETROLEUM. 169 



siuce this oil with a mixture of ordinary concentrated nitric and sulphuric 

 acids, on shaking, immediately develops sufficient heat to raise the tem- 

 perature to vigorous ebullition of the acid mixture, and to destroy a large 

 portion of the hydrocarbon. In all these experiments the initial reaction 

 had to be controlled by cooling. 



Concerning the number of carbon atoms in the hydrocarbon I have 

 separated at this point, it seems to be well established by the molecular 

 weight, C12H24) and by the composition of the monochlor derivative, 

 C12H23CI. Yet in a product with a specific gravity much higher than 

 this purified hydrocarbon, Pelouze and Cahours obtained numbers by 

 analysis, as shown above, page 141, closely supporting the formula 

 C13H26. and from the hydrocarbon a chlorine derivative, C13H27CI, also 

 supported by analytical values closely corresponding to the theoretical 

 composition required for this formula. 



Summary of Results. 



1. Pennsylvania petroleum is composed chiefly between 150° and 220° 

 of decane, boiling point 163°-164°; decane, boiling point 173°-174°, 

 probably normal decane ; hendecane, boiling point 196°-197° ; and dode- 

 cane, boiling point 214°-216°. It contains also in smaller proportions 

 the series of aromatic hydrocarbons boiling within these limits. Allusion 

 has already been made to mesitylene, cumol, pseudocumol, cymol, iso- 

 cymol, durol, isodurol, and no doubt others could be identified with suffi- 

 cient quantities of the petroleum distillates. 



2. The composition of Ohio Trenton Limestone petroleum within the 

 same limits is represented by the same members of the series C„Fl2„+2» 

 and the higher specific gravity of these distillates is caused by a larger 

 proportion of aromatic hydrocarbons. 



3. The constituents of Canadian Corniferous limestone petroleum from 

 Petrolia, within these limits of temperature, are the same at 163° and 

 173°. But the hydrocarbons collecting at 196° and 214° have the com- 

 position represented by the series C„H2„. Probably a better knowledge 

 of these higher distillates will be gained when the true composition of 

 American petroleum above 220° has been ascertained. The proportion 

 of aromatic hydrocarbons is greater in Canadian than in Ohio petroleum. 

 There are indications in all these petroleums that the heavier constitu- 

 ents include other bodies than the aromatic hydrocarbons, which will 

 require for their identification the manipulation of large quantities of 

 distillates. 



