OG . Natural History of Volcanos and Earthquakes. 
could be pursued from ten to twenty feet in a horizontal diree- 
tion, or nearly so, and which doubtless were prolonged still far- 
ther. 
If the carbonic acid gas arises from below with considerable 
elasticity, and the cleft contracts very much from 6 to e¢, then it 
may easily hapyen that the meteoric water may penetrate but 
little below 6. In this case, the column of water a b, will be as 
it were supported by the column of gas,+ and at the point of con- 
tact, a constant absorption of the gas will be going on. In this 
manner, probably, are those mineral springs formed, which 
abound in carbonic acid gas, but contain very little solid matter, 
and whose average temperature exceeds but little that of the 
neighboring wells. It must frequently be the case, moreover, 
that many springs which rise from a greater depth, and there- 
fore are originally warm, become cooled by mixture with cooler 
springs. 
The warmest of the mineral springs in the environs of the 
Laacher See exceed the mean temperature of the ground by 7° 
to 10° Fahrenheit. What is worthy of remark is, that they rise 
from the deepest spots of the valley, where, therefore, their sub- 
terraneous channels are proportionably deepest under the rock, — 
and possess already a relatively higher temperature. On pursuing 
the mineral springs up the valley, we find that their temperature 
decreases in a somewhat regular ratio.t 
The proportionably small number of clefts in the clay-slate 
rocks may certainly account for the circumstance, that, in the 
Laacher Nee, the Eifel, and the Taunus, so few springs of con- 
siderable high temperature occur, though the channels of the cat- 
bonic acid gas lead down to such great depths, probably to points 
where a red heat exists. Such warm springs may perhaps owé 
their existence to the favorable circumstance of a cleavage surface, 
which intersects the strata at an obtuse angle, leading up from the 
cleft between the volcanic cone and the clay-slate rock, and open- 
ing at a valley, ascd. Perhaps the warm springs at Bertrich 
* Neues Jahrbuch de Chem. et Phys. t. viii, p. 423, year 1833. 
+ The rising and falling of the periodic spring of the salt-work at Kissingen, is 
doubtless a ke ae a of the elasticity of carbonic acid gas. See Poggendarif's 
Ann. t xl, p. 
t Soin the sed of Taunus mountains, the warm springs rise deep in the valley, . 
the cold acidulous springs on the heights. 
re enw dP 
