INTO BROWN OR WOOD-COAL. 325 



formed of common spring water which ascends 

 from below, and of carbonic acid which issues from 

 the sides of the spring. The same fact has been 

 shown to be the case in the famed Fachinger 

 spring, by M. Schapper. 



The carbonic acid gas from the springs in the 

 Eifel is, according to Bischof, seldom mixed with 

 nitrogen or oxygen, and is probably produced in 

 a manner similar to that just described. At any 

 rate the air does not appear to take any part in 

 the formation of these acidulous springs. Their 

 carbonic acid has evidently not been formed either 

 by a combustion at high or low temperatures ; 

 for if it were so, the gas resulting from the com- 

 bustion would necessarily be mixed with f of 

 nitrogen, but it does not contain a trace of this 

 element. The bubbles of gas which escape from 

 these springs are absorbed by caustic potash, with 

 the exception of a residuum too small to be appre- 

 ciated. 



The wood coal of Dorheim and Salzhausen must 

 have been formed in the same way as that of the 

 neighbouring village of Laubach ; and since the 

 latter contains the exact elements of woody fibre, 

 minus a certain quantity of carbonic acid, its com- 

 position indicates very plainly the manner in which 

 it has been produced. 



The coal of the upper bed is subjected to an in- 

 cessant decay by the action of the air, by means 



