On Mineral Waters, G9 



of naturally warm springs, and water artificially heated, cceteris 

 paribus, require the same time to cool ; a fact which has since 

 been confirmed by the experiments of Professors Reuss, Neu- 

 mann, and Steinmann, on the waters of Carlsbad ; by Pro- 

 fessors Schweigger, Ficinus, and Reuss, on those of Toplitz, 

 and by Dr. Salzer, on the springs of Baden, near Vienna. 



On a closer inquiry into the theory of the formation of ther- 

 mal springs, the positions laid down for the origin of their tem- 

 perature offer us no grounds to assume in them an extraordi- 

 nary capacity for caloric. The hypothesis which derives their 

 heat from the decomposition of pyrites, or from beds of burning 

 coals, has found its refutation in the chemical and philosophical 

 reasonings of Professor Berzelius;* and the view which he 

 himself has shaped out, has, from a multitude of facts, by far 

 the greatest title to probability. 



Hot springs, he observes (as well as exhalations of gases and 

 of steam), occur in the vicinity of all active volcanos ; it is, 

 therefore, probable that such waters owe their temperature to 

 their passage through channels heated by volcanic fire. With 

 regard to the other fervid springs we are acquainted with, most 

 of which will be found to lie contiguous to extinguished vol- 

 canos, or at least in a soil bearing the stamp of volcanic forma- 

 tion, there is reason to suppose, either that volcanic action still 

 goes on in the interior of the earth, or that glowing masses, the 

 remains of primeval volcanic processes, still exist there. That 

 the former case obtains, with reference to some springs, seems 

 evident from the earthquakes that have been experienced in 

 their neighbourhood ; and the possible existence of glowing 

 masses in the interior of the earth, and requiring thousands of 

 years to cool, will be conceived with less difficulty, when it is 

 considered that volcanic productions are amongst the worst 

 conductors of heat ; yet wholly enveloped in immense strata of 

 such as these glowing masses must be, they can only part 

 with their temperature by conduction — never by radiation. 



Of the remarkably bad conducting power of volcanic products 

 we are furnished with abundant proofs. Thus, Sir William 

 Hamilton observed, in 1769, that the lava which flowed at 

 Vesuvius in 1766, was still smoking. During the eruption of 



* Vide Transactions of the Royal Academy of Sciences, at Stockholm, 1822, 



