370 CONVERSION OF WOOD 



mon water meeting with carbonic acid during their 

 ascent, and becoming impregnated 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 

 supplied 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 dis- 

 appeared, and in its place is found a spring of com- 

 mon 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. Wilhelmi 

 observed some time since, that they are 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 BischofF, 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 for- 

 mation of these acidulous springs. Their carbonic 

 acid has evidently not been formed either by a com- 

 bustion at high or low temperatures ; for if it were 

 so, the gas resulting from the combustion would ne- 

 cessarily be mixed with | 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 appreciated. 



The wood coal of Dorheim and Salzhausen must 

 have been formed in the same way as that of the 

 neighboring village of Laubach ; and since the latter 

 contains the exact elements of woody fibre, minus a 



