PETROL 283 



widely separated countries the operations are essentially 

 similar. 



Another picture (Fig. 79) shows the appearance of an oil-field in 

 the Pennsylvanian regions, and for comparison with it a view in 

 Texas (Fig. 80) and another in California (Fig. 81) nearly twenty 

 years later. From these it will be seen that the aspect of a petroleum 

 field with its clustering derricks and associated tanks for oil re- 

 mains much the same as in the earlier periods of development in 

 the older fields of Pennsylvania. The country, however, is very 

 different superficially, as the Pennsylvanian oil-fields are situated 

 among well- wooded hills, while the Californian wells are sunk in 

 a district which is largely desert. The geological character of the 

 rocks from which the oil is extracted is also different in these 

 three regions. In Pennsylvania the oil-bearing sandstone rocks 

 belong to the Devonian system below the carboniferous series, 

 while the Californian oil is derived from Eocene and Miocene 

 beds, and that of Texas also from other formations more recent 

 geologically than those of Pennsylvania. In no case is the oil 

 deposit found in contiguity with beds of coal or shale, but in 

 cavities generally, but not always, not in communication with one 

 another. This is important to remember in connection with the 

 question as to the origin of petroleum, which will be briefly 

 discussed on a later page. 



Turning now from the western hemisphere toward the east, 

 the great Russian oil-field, extending through the Caucasian 

 region chiefly along the shores of the Caspian Sea, is of the 

 utmost commercial importance. 



From prehistoric times this district has been the resort of all 

 the East for the sake of the oil exuding from the ground. The 

 inflammable gas which escapes in so many places was naturally 

 the wonder not only of the natives, but of numerous pilgrims 

 from afar. 



Jonas Hanway, an English merchant in the reign of George II, 

 visited the Caspian, and on his return, published in 1754, An 

 Account of British Trade over the Caspian Sea. In this book he 

 gave an interesting account of the phenomena which had 

 attracted the Fire- worshippers from Persia and India for many 

 centuries. The worshippers in Hanway's time all came from 

 Bombay, the home of so many of the Parsees, the last disciples 

 of Zoroaster. The ruined remains of the temples in which the 

 priests tended the eternal flames which were the object of 



