208 THE POPULAR SCIENCE MONTHLY. 



not expelled from the Caucasus until the Mohammedans subjugated 

 the Persian Empire, when they were driven into the Rangoon, on the 

 Irrawaddy, in India, one of the most noted petroleum-producing dis- 

 tricts of the world. 



Petroleum and natural gas are so intimately related that one would 

 hardly dare to say whether the gas proceeds from petroleum or the 

 petroleum is deposited from the gas. It is, however, safe to assume 

 that they are the products of one material, the lighter element sepa- 

 rating from the heavier under certain degrees of temperature and 

 pressure. Thus, petroleum may separate from the gas as asphaltum 

 separates from petroleum. But some speculative minds consider nat- 

 ural gas to be a product of anthracite coal. The fact that the great 

 supply-field of natural gas in Western Pennsylvania, New York, West 

 Virginia, and Eastern Ohio, is a bituminous and not an anthracite 

 region, does not, of itself, confute that theory ; as the argument for 

 it is, that the gas may be tapped at a remote distance from the source 

 of supply, and, whereas anthracite is not a gas-coal, while bituminous 

 is, we are told to suppose that the gas which once may have been a 

 component part of the anthracite was long ago expelled by Nature, 

 and has since been held in vast reservoirs with slight waste, awaiting 

 the use of man. That is one theory ; and upon that supposition it is 

 suggested that anthracite may exist below the bituminous beds of the 

 region lying between the Alleghany Mountains and the Great Lakes. 

 Another theory is, that natural gas is a product of the sea-weed depos- 

 ited in the Devonian stratum. But, leaving modern theories on the 

 origin of natural gas and petroleum, we may suppose the natural gas- 

 jets now burning in the fissures of the Caucasus to have started up in 

 flames about the time when, according to the Old Testament, Noah 

 descended from Mount Ararat, or very soon thereafter. In the lan- 

 guage of modern science it would be safe to say that those flames 

 sprang up when the Caucasus range was raised from beneath the sur- 

 face of the universal sea. The believer in biblical chronology may 

 say that those fires have been burning for four thousand years the 

 geologist may say for four millions. 



We know that Alexander the Great penetrated to the Caspian ; 

 and in Plutarch we read : " Hence [Arbela] he marched through the 

 province of Babylon [Media?], which immediately submitted to him, 

 and in Ecbatana [?] was much surprised at the sight of the place 

 where fire issues in a continuous stream, like a spring of water, out 

 of a cleft in the earth, and the stream of naphtha, which not far from 

 this spot flows out so abundantly as to form a large lake. This 

 naphtha, in other respects resembling bitumen, is so subject to take 

 fire that, before it touches the flame, it will kindle at the very light 

 that surrounds it, and often inflame the intermediate air also. The 

 barbarians, to show the power and nature of it, sprinkled the street 

 that led to the king's lodgings with little drops of it, and, when it was 



