Hot and Thermal Springs. 205 



From the observations'of Magnus* and Erman, -f- in the 

 sounding at R'udersdorf, the same depth is found to be from 

 107.7.6 to 115 — 1.2 feet, and from more recent observations t 

 121—3.8 feet. 



Taking the observations at Geneva, cited in the last chapter, 

 which were made under the most favourable circumstances, as 

 the standard, the following are found to accord the most nearly 

 with them : — 



Geneva, . . . . . J22 — 2.8 Feet. 



£r;i^e6!r(7e, from observations in enclosed waters, 13C — 11.3 ... 



Monk-Wearmouth, ?Yora. sd\t-yia.ter s^rin^s, ^. 133 — 6.8 ... 



Cornipa/;, from springs, . . . 122 — 6.7 ... 



Comuja/^, from enclosed waters, . . 118 — 3.5 ... 



.Riirferirfoj/, from rising springs, . . 121 — 6.9 ... 



Uralian Mountains, from a comparison of the most ■» 



'^ >- 1 23 7 5 



authentic observations in those regions, § . J 



A comparison of these results leads to some interesting con- 

 clusions. 



The near coincidence of these results is certainly not acci- 

 dental. It rather shews that the circumstance which influences 

 the increase of temperature towards the centre of the earth, 

 namely the configuration of its surface, must be nearly equal in 

 all those places. The greatest difference is between Geneva 

 and the Erzgebirge. In Chap. XVII, I have already dis- 

 cussed the question, whether the value of n is the same, all 

 other circumstances being the same, under a plain, under deep 

 valleys surrounded by high hills, and under mountains. Should 

 diflFerences be found, they must be the greater between the two 

 latter cases, which are the extremes in the configuration of the 

 earth. The position of Geneva may be considered as the one 

 extreme, and the Erzgebirge, in general, as the other. But 

 whether their difference is really owing to that cause, or rather 

 to the circumstance that the Erzgebirge is more exposed to the 

 influence of the atmosphere, on account of the extent of the 

 mines, we will leave undecided. However, the result obtained 

 at MonJc-Wearmouth, which so nearly accords with the value 

 found in the Erzgebirge, speaks in favour of the latter suppo- 



* Poggend. Annal. vol. xxii. p. 146. 



t Abhandlung. der Akad. der Wissenschaften zu Berlin. 1831. P. 268. 



* Poggend. Annal. vol. xxviii. p. 233. 



§ Jtrman junr. in Kamtz Lehrb. der Meteorologie, voL ii. p. 578.|i 



