496 TRANSACTIONS OF THE AMERICAN INSTITUTE. 



According to the amount of carbon wliicli they contain. Different 

 specimens from the same vein of coal, differ materially in the 

 relative proportion of their constituent elements ; but the follow- 

 ing table exhibits an approximation : 



CARBON, 



per cent. 



Anthracite 85 



Semi-Anthracite . 73 



Bituminous. 63 



Cannel 27 



Bituminous Shale. 17.7 



The carbon is the element which gives to coal much of its 

 value for generating heat. Coals, other than anthracite, con- 

 tain the gases, oxygen and hydrogen, which form the flame of 

 coal. When the coal contains sulphur, the hydrogen combines 

 with it, forming sulphuretted hydrogen. For this reason, when 

 coal gas is burnt in cities, paint, whose basis is white lead, grows 

 dark more rapidly than it used to do before gas light was intro- 

 duced, and it is more difficult to keep silver ware bright. It is 

 impossible to dry coal thoroughly without artificial heat, and 

 there is left, as the analysis just quoted shows, one or two per 

 cent, of water. The ashes contain silica, alumina, iron, lime, 

 soda, potash, sulphuric acid, chlorine, phosphoric acid and mag- 

 nesia, singl}' or combined. 



Dr. S. then exhibited drawings of the coal formations of the 

 Monongahela, showing the different depths at which the impor- 

 tant veins lie beneath the surface. 



The Nova Scotia coal lies north of the Bay of Funday. and was 

 formerly abundant in our market, under the name of the "Ficton 

 coal." There is also a narrow trough, commencing in Rhode 

 Island, and running up to Worcester, Mass., about thirty-five miles 

 in length, containing an anthracite coal so hard that it is said 

 that to burn a ton of it, we must burn two tons of Pennsylvania 

 coal. These two coal formations belong to the same era in the 

 M'orld's history, and had no connection with the appalachian 

 system. 



It is coal which has brought about that great increase of the 

 wealth of England, within the last century, which enabled her, 

 throughout the continental wars, to supply the armies of Europe 

 with her gold, and the world with her manufactures. It has made 

 England the mother of colonies. She still possesses the only 



