RESEAKCHES UPON THE CHEMICAL PROPERTIES OE GASES. 227 



paraffins was obtained, compounds not found elsewhere in nature than in pe- 

 troleum. 



This has led to the revival of an older theory as to the origin of petroleum and 

 gas, i. e., that they have resulted from the distillation under pressure and at low tem- 

 peratures of the accumulated remains of marine life buried under the sediments of 

 the ancient Devonian seas. 



Much has been written in support of the hypothesis of Engler, and it may be 

 said to have gained very general acceptance in Europe. 



Ochsenius ( Cliem. Zeitung, 1891, p. 936) has summarized many of the argu- 

 ments usually adduced in support of the hypothesis. 



This author says, " Concerning the origin of petroleum, there is now no doubt 

 that, with a few exceptions, animal remains (mainly of marine life) have yielded the 

 raw material." 



Originally the opinion was held that it was derived from vegetable matters, be- 

 cause the accumulation of animal remains sufficient to account for its formation by 

 any distillation process in the rocks could not be explained. Distillation of vege- 

 table matters would, however, have left greater deposits of coal (as a residue in the 

 Devonian rocks). But petroleum occurs in rocks of marine formation where coal is 

 uncommon. Rocks in which plant remains are found do not contain bitumen (petro- 

 leum). If animal remains are associated with those of plants, then bitumen is usu- 

 ally found. 



The objection urged against the hypothesis of Engler, that nitrogen does not 

 occur in petroleum, is easily overcome by the fact that nitrogen of animal tissues 

 tends finally to produce ammonia, and this in the case of petroleum may have been 

 carried away in solution by water ; hence, the absence of nitrogen compounds. 



From Engler's experiments, it appears that animal fats are the chief source of 

 petroleum. 



It is true that fatty matters do not ordinarily sink in water, although Von 

 Guembel, in the voyage of the Gazelle, found fat globules in dredgings from the 

 bottom of the Atlantic Ocean, in water 15,000 feet deep. 



Putrefactive changes would tend to yield considerable quantities of ammonia 

 and carbon dioxide. These in presence of salt water would produce alkali bicarbon- 

 ate and ammonium chloride. Hence, alkaline waters might be looked for in the 

 neighborhood of petroleum. The petroleum at Pcchelbronn is associated with water 

 containing 0.5 per cent, of alkaline carbonate. (In Western Pennsj'lvania, many 

 cases are known of water having a decided alkaline reaction in the neighborhood of 

 gas wells. In the Murrysville gas territory, water of alkaline reaction was so abun- 



