1897.] COMPOSITION OF AMERICAN PETROLEUM. 131 



At the time when the French chemists conducted their investiga- 

 tions on American petroleum, both Pennsylvania and Canadian 

 products were to be obtained in the European markets, especially 

 in France, where Canadian oil seems to have been more easily 

 obtained at times than Pennsylvania oil. In the papers of Pelouze 

 and Cahours, allusions are made to American petroleum, and to 

 Canadian petroleum. Their second paper {Compi. Rend., 56, 

 505, 1863), begins with the following paragraph: ''Dans un 

 premier examen que nous avons fait des produits les plus volatils 

 de I'huile provenant des forages qu'on pratique depuis quelques 

 annees sur plusieurs points de I'Amerique, et notement au Canada, 

 nous avons signale I'existener d'un homologue du gaz des marais 

 dont la composition est representee par le formule Cj-Hi^ = 4 vol. 

 vap." 



With no previous knowledge as to the properties of crude oils from 

 these different sources it would not be surprising if they were used 

 indiscriminately. At any rate an examination of the papers of Pe- 

 louze and Cahours does not reveal the source from which their crude 

 oil was obtained. But a comparison of their results as to specific 

 gravity and percentage composition, together with their method of 

 purification, with the same properties of distillates more thoroughly 

 purified (Mabery, Inc. cii., p. 171), presents conclusive evidence that 

 Pelouze and Cahours had in hand, in at least a portion of their work, 

 distillates from Canadian oil. Furthermore, in some of their distil- 

 lates showing a higher specific gravity than it is possible to obtain 

 after suitable purification, even from Canadian petroleum, analytical 

 values correspond closely to the series CnH.,n_2 ; CuH.^g at i96°-2oo°, 

 and C13H28 at 2i6°-2i8°. That Canadian crude oil was to be ob- 

 tained in England at that time is evident from the work of Schor- 

 lemmer, who demonstrated the presence in oil from Canada of the 

 aromatic hydrocarbons CnHgn-e- 



The series C^Hoq, found by Warren in Pennsylvania petroleum, 

 has been accepted by some as showing the presence of the ethylene 

 hydrocarbons, and by others as indicating the naphthenes. That 

 the naphthenes are excluded below 216° in Pennsylvania oil by the 

 wide difference in specific gravity has been pointed out (Mabery, 

 loc. cit., 125). The ethylene hydrocarbons are also excluded by 

 the want of additive power in these distillates for the halogens. 



Indeed, after removal of the aromatic hydrocarbons C^H,,„_6, the 

 series C^H.^ disappears altogether from distillates within these 



