GEOLOGICAL SOCIETY OF PENNSYLVANIA. 407 



Mean Results of the Temperature of Six Mines. 



Depth in feet. 



Hue! 

 Neptune. 



Botel 

 Lack. 



Little 

 Bounds. 



Ding- 

 dong. 



Huel 

 Vor. . 



Dolcoatli. 



Mean. 





Air 



Wat 



Air 



Wat 



Air 



Wat 



Air 



Wat 



Air 



Wat 



Air 



Wat 



Air 



Wat 



120 to 150 



57 





59 



57 







OO 













57 



57 



150 " 200 



56 





oO 



5o 



54 

















57 



56 



rtAA L£ OCA 



200 " 250 



56 





oi 





57 



CC 



OO 







/2A 



dO 



57 







58 



56 



OCA C£ OAA 



250 '* oOO 



56 



CC 



DO 



oi 



Firt 



o9 



57 



CA 



59 











60 





58 



58 



OAA ££ OKA 



dOO " o50 



CO 



5o 



C A 



54 







55 



CC 



55 















57 



55 



OCA iC ACiCK 



Sou " 4U(J 





57 



DO 



02 







55 













60 



59 



4AA ££ /I C A 



400 " 450 



60 





bo 









C£J 



OO 



o4 











61 



54 



/ICA ££ CAA 



450 " 500 















uu 



59 











uu 



oy 



KAA ££ CCA 



500 " 550 



67 



67 



67 



68 











61 



60 



64 





65 



65 



OOKj uuu 















63 



63 











63 



63 



600" 650 















62 



63 



61 



63 







62 



63 



650 " 700 















64 



64 



65 



64 







65 



64 



700" 750 



















67 



65 







67 



65 



750 " 800 



















68 



68 







68 



68 



800 " 850 



















66 



66 







66 



66 



850 " 900 





















68 







* 



68 



900 " 950 





















71 



62 





62 



71 



950 " 1150 























70 



66 



70 



66 



1150 " 1260 























71 



71 



71 



71 



1260 " 1350 























76 



74 



76 



74 



1350 " 1400 























83 



79 



83 



79 



* Here there was a strong current of air. 



In giving the preceding statement relative to the rate 

 of increase of temperature in mines according to their 

 depths, it has been assumed that the increase commences 

 immediately below the surface. This, however, cannot 

 be considered as the case ; and although it is dijQicult to 

 define the precise point, it was placed with some degree 

 ofi reason at about 200 feet. 



From all that has been advanced, it would be conclud- 

 ed, that there exists a high temperature in the interior 

 of the earth. If this is admitted, what is to be said to 

 the fact, and one which has been considered not readily 

 reconcilable with the doctrine of internal heat, that the 

 mines of Saxony, situated 1500 feet above the level of 

 the sea, are of equal warmth with those of Cornwall, 

 which are below the sea level. How also can be ac- 



