Hot and Thermal Springs. 1SI7 



meteoric waters would also have free access to that place, and 

 would either increase, diminish, or entirely extinguish the che- 

 mical action ; or would somewhere reappear charged with sub- 

 stances which had taken a part in the process. Of this, how- 

 ever, experience furnishes no examples. Secondly, if we sup- 

 pose the process to be an oxidation, the free admission of the 

 oxygen of the air would be necessary. But then the atmo- 

 spheric waters would also have access, since such a process can- 

 not be conceived without a communication with the atmosphere, 

 and nitrogen gas would be evolved in much greater quantities 

 than are found here and there sparingly emitted from some few 

 mineral springs. 



Thirdly, if this oxidation be supposed to take place at the 

 expense of water, hydrogen gas must be evolved, which is also 

 contrary to experience. Such an explanation of the heat of 

 mineral springs necessarily presupposes a structure in the inte- 

 rior of the earth of quite a peculiar nature, viz., one cavity in- 

 closed within another, and one to which nothinfj analoorous has 

 been found in the working of mines ; the theory must, there- 

 fore, be considered as untenable. 



It must, however, not remain unmentioned, that subterrane- 

 ous fire may in solitary instances give rise to warm springs. 

 Examples of this have occurred in tl^ Planitzer Adit, near 

 Zwickau, and at Holdenstaedt near Eisleben in Thuringia.* 



Lastly, it must also be taken into consideration, that former- 

 ly, when only the few commonly called hot-springs, such as 

 Carlsbad, Aachen, &c. engaged the attention of philosophers, 

 the explanation of this phenomenon could only be sought in 

 local causes. Becher's hypotheses with respect to Carlsbad, 

 that water containing common salt flows ov^er a depot of burn- 

 ing iron-pyrites, or Klaproth''s supposition that the water is 

 heated by a considerable bed of coal, set on fire by iron-pyrites, 

 were, therefore, for the moment considered satisfactory. Inde- 

 pendently of the well-grounded objections of Von Buch and Ber- 

 zelius to these hypothesis, there would still remain much for us 

 to account for, even if we had very satisfactory explanations of 

 those properly called hot- springs. For as the rising of thermal 



• Kuhn Handbuch der Gcognosie, v©L i. 2ft 



