REPORT ON MINERAL ANT) THERMAL WATERS. 61 



vian Peninsula *, nor those of Kupffer on the Ural range f ? ab- 

 solutely conclusive, as to the generality of the supposed law even 

 in the high latitudes to which they refer. 



The elevation of temperature may, for ought we know, be con- 

 fined to the neighbourhood of uplifted chains of mountains ; it 

 may be a consequence of those great natural events to which are 

 owing the disturbances there experienced ; and consequently it 

 may not extend to the great plains of Russia or Siberia, where 

 no such local influences exist. Or if it should be found on further 

 examination to be general in northern latitudes, it will still re- 

 main to be discussed, before referring it to central heat, whether 

 the phaenomenon may not depend upon the cause suggested by 

 Von Buch in the memoir before referred to, namely, that the 

 transmission of temperature through the earth chiefly takes 

 place by the infiltration of water, a cause which, of course, 

 ceases to operate below 32°. 



Granting, however, that the springs, which Bischof has no- 

 ticed, owe their excess of temperature in part to a generally per- 

 vading cause of heat, we have still to account for the enormous 

 differences in this respect existing between one and another, and 

 this is what I now propose to consider. 



The degree in which they exceed the mean of the climate is 

 dependent, amongst other circumstances, on the elevation on the 

 earth's surface at which they issue. 



Von Buch X has given various instances of springs, belonging 

 to the same district, but bursting out at diff"erent heights, which, 

 though they may correspond in mineral and gaseous impregna- 

 tion, differ materially in temperature, the lowest being the hot- 

 test. 



Boussingault§ also states, that in the littoral chain of Vene- 

 zuela the temperature of the thermal springs is less in propor- 

 tion as their absolute height is greater. 



Thus the warm spring of Las Funcheras near Puerto Cabello, 

 which approaches the level of the sea, possesses a temperature of 

 97° cent. That of Manaro, at a height of 476 metres, has only 

 one of 64°; and that of Onoto, at 702 metres, only 44°-5. 



This regularity, however, does not extend to hot springs in 

 immediate contact with volcanos. Von Buch || conjectures, that 

 the heat of such springs is derived from the carbonic acid which 

 impregnates them, and which possesses itself a high temperature, 

 as having proceeded from a great depth. 



* Annals of Philosophy, vol. iv. 1814, translated from Gilbert's Annalen. 

 f Kupffer in Edinburgh New Phil. Journal, vol. xxii. 

 I PoggendorfFs Annalen, vol. xxii. § Annales de Chimie, 1831. 



y Poggendorff's Annalen, vol. xii. p. 41 5. 



