CARBON AND ITS COMPOUNDS. 31 



and therefore its Gree name electron gave rise to the 

 term electricity. 



46. Bitumen. There are various kinds of bitumen, 

 some solid and some fluid. They are supposed to be 

 produced from vegetable matters buried in the earth ; 

 and as they are commonly found in the neighborhood of 

 active or extinct volcanoes, it is inferred that they have 

 been driven to the surface by the internal heat of the 

 earth. I will notice some of the varieties. Asplialtum^ 

 or mineral pitch, is solid. It was the chief ingredient 

 in the cement used in building the walls of Babylon and 

 of the Temple in Jerusalem. It has lately been success- 

 fully employed in forming a composition for paving 

 streets, and a cement for covering roofs. It is very 

 abundant on the shores of the Dead Sea, which is called 

 Asphaltites for this reason. The most remarkable local- 

 ity of it is the Pitch Lake in the island of Trinidad. It 

 is about a mile and a half in circumference, and while 

 the asphaltuin is near the shores sufficiently hard at most 

 seasons to sustain men and quadrupeds, it grows soft and 

 warm as you go toward the centre, and there it is in a 

 boiling state. Petroleum is a dark fluid, which becomes 

 solid on exposure to the air. This is so abundant in the 

 Burmese Empire that it is used as lamp-oil, and as fuel, 

 by being mixed with ashes or earth. The most power- 

 ful springs of it there are on the Irawady. In one local- 

 ity there are 520 wells, yielding annually 400,000 hogs- 

 heads. There are many localities of petroleum in this 

 country. It was formerly collected and sold by the In- 

 dians ; and, as the Senecas were prominent in the trade, 



the light, was found to have been written on paper which, by its wa- 

 ter-mark, was shown to have been manufactured subsequent to the 

 date of the document. So, in these imitations of amber, the date 

 fixed by the recent character of the insects shows, to the practiced eye 

 of one who understands the distinctions between insects of the present 

 age and those of ages previous to the creation of man, that the speci- 

 mens are not real amber. 



