324 CONVERSION OF WOOD 



The peculiar process by which the decomposi- 

 tion of these extinct vegetables has been effected, 

 namely, a disengagement of carbonic acid from 

 their substance, appears still to go on at great 

 depths in all the layers of wood coal. At all events 

 it is remarkable that springs impregnated with 

 carbonic acid occur in many places, in the country 

 between Meissner, in the electorate of Hesse, and 

 the Eifel, which are known to possess large layers of 

 wood coal. These springs of, mineral water are 

 produced on the spot at which they are found ; the 

 springs of common water meeting with carbonic 

 acid during their ascent, and becoming impreg- 

 nated with it. 



In the vicinity of the layers of wood coal at Salz- 

 hausen (Hesse Darmstadt) an excellent acidulous 

 spring of this kind existed a few years ago, and sup- 

 plied all the inhabitants of that district ; but it was 

 considered advantageous to surround the sides of 

 the spring with sandstone, and the consequence 

 was, that all the outlets to the carbonic acid were 

 closed, for this gas generally gains access to the 

 water from the sides of the spring. From that 

 time to the present this valuable mineral water has 

 disappeared, and in its place is found a spring of 

 common water. 



Springs of water impregnated with carbonic 

 acid occur at Schwalheim, at a very short distance 

 from the layers of wood coal at Dorheim. M. Wil- 

 helmi observed some time since, that they are 



