72 Dr Daubeny 07i Thermal Springs^ 



If it be asked why, admitting that volcanic action takes place 

 generally wherever thermal waters occur, and consequently that 

 it is found in the interior of continents, I still think it necessary 

 to regard water as the exciting cause, — I reply, that the large 

 quantities of hydrogen given oiF in combination with sulphur, 

 the free muriatic acid present in the vapour evolved, together 

 with the common salt and carbonate of soda that effloresce in 

 the spiracles of most volcanos, appear to me inexplicable on 

 every other supposition. Neither can it be denied that the great 

 majority of those in activity are near the sea, although the re- 

 cent investigations of Humboldt have attached a greater cur- 

 rency to the statements which had been before given in my De- 

 scription of Volcanos, on the authority of Remusat and Klap- 

 roth, with regard to the existence of burning mountains still in 

 a state of vigorous action in central Asia. 



These statements excited but little attention at the time they 

 were put forth, because it was seen that the necessary details 

 were too imperfectly known to allow of our building much upon 

 their assumption ; neither do I see that Humboldt himself, in 

 his otherwise interesting memoir *, has been able to collect many 

 more well authenticated particulars relative to this portion of 

 the geography of central Asia. 



Yet, taking the position of the supposed volcanos as there 

 given, we shall see nothing very inconsistent with that in which 

 the majority of other igneous mountains are found to be placed. 

 The extinct volcano of Aral-tube, which lies between the two 

 chains of the Great Altai and the Teen-shan or Celestial Moun- 

 tains, is an island in the Lake of Alakul. 



The Solfatera, as Remusat calls it, or the active volcano, as 

 Humboldt is inclined to consider it, which goes by the name of 

 Peechan or the White Mountain, lies on the northern declivity 

 of the Celestial Mountains, very near the Lake of Issikoul, 

 which Humboldt admits to be twice as considerable as that of 

 Genear. 



In like manner, the Solfatera of Urumtzi, and the fissures 

 in its neighbourhood, which give out vapours of sal-ammoniac, 

 lie near the Lake of Darlai ; and the volcano of Hotscheu, which 



• See this Journal, October 1831, and also present Number. 



