Peckham — Nitrogen Content of California Bitumen. 255 



cipitation of the acid radical as a hydrate within the oil, in which 

 it dissolves, producing a viscous tar. When this decomposi- 

 tion has proceeded so far that water in appreciable quantity 

 becomes a constituent of the compound, the bitumen is no 

 longer petroleum but maltha. This water of hydration sepa- 

 rates only when the maltha is heated to a comparatively high 

 temperature. It will never separate by difference of specitic 

 gravity at comparatively low temperatures ; but requires a tem- 

 perature at which the hydrate is decomposed into a dense oil 

 very much less viscous than the hydrate on the one hand and 

 water on the other. 



As the change proceeds the bitumen becomes solid asphal- 

 tum, and a new compound, that is found in maltha only in 

 small quantity if at all, appears. This is Boussingault's asjphal- 

 tane* which was assumed by him to be an oxidized product in 

 which oxygen was substituted for hydrogen. Recent experi- 

 ments not yet completed indicate that asphaltene is not a sim- 

 ple substance, but that it may be resolved by suitable solvents 

 into a compound containing oxygen and a compound that 

 represents the original hydrocarbon, minus a portion of its 

 hydrogen, by virtue of which it is no longer soluble in those 

 fluids that dissolve the hydrocarbon in its original form. 



The work that I have been able to accomplish since I first 

 became aware of the existence of these substances in January 

 last, as constituents of California bitumens, has been mainly 

 technical. As related to purely scientific considerations it may 

 be compared to the action of a skirmish line, which by draw- 

 ing the fire of a vast army has revealed its presence. I am 

 confident that the solution of problems of great importance to 

 all of the varied technical applications of bitumen awaits the 

 careful investigation of the nitrogen content of the immense 

 accumulations of bitumen in all its forms found in California. 



Perhaps it may be demonstrated, that the permanent asphal- 

 tic constructions of antiquity were made of asphalts of animal 

 origin, consisting of hydrocarbons of the benzole series instead 

 of those of vegetable origin, consisting of terpenes. 



University of Michigan, Ann Arbor, Michigan, June 4th, 1894. 



* Annales de Chemie et de Physique (2), lxiv, 141; Journal of the Franklin 

 Institute, xxiv, 138; New Bdinburg Philosophical Journal, sxii, 97. 



