154 



Tabulated 

 temperatures 

 •nd depths, 

 with remarks. 



ON SUBTERRANEAN HEAT. 



1 1 1 rt .• 1 . ,. Tempo- Depth. 



hour on a board tioatjiij^ on the water, mni- rauire. 



776 



77(J 



cated *. Q4p 



10. Immersed in the water it equally indi- 

 cated .....'.......' (J40 



All the water that enters into this southern 

 part of the mine runs into the lake, from which 

 it is pumped up. 



11. The temperature of the water issuing 



from the pumps into the gallery No. 7 was • • 65*1® 587 ''G 



Following the course of this gallery the wa- 

 ter runs to another shaft in the north part of 

 ^e mine. 



12. There it mixes with a small quantity of 



V^ter, the temperature of which is • • « 57*2° 391 * •$ 



13. And when the water thus mixed is con- 

 veyed by the pumps to the discharging g^allery iiTO-> at: 

 it raises the thermometer to 63-3^ ti -rq v. 



General de- 

 <!uctions. 



Katu'aT tem- 

 jierature 



agrees with the 

 Iheory. - 



Increases with 

 4h3 depth. 



Increased in 

 one part by 

 therm al wa- 

 ters. 



Ca'.i?e of their 



We have here two classes of observations to distinguish ; 

 those made in the north part of the mine, I, 2, 3, and 12; 

 and tliose made in the south part. 



The first appear to me to indicate the natural tempera- 

 ture of the soil. No. 1, made 20 or 30 yards below the sur- 

 face of the ground over that part, of the mine, must be con^ 

 sidered as giving the true degree of heat of the surface of 

 the earth in that country. I perceive no cause, that can 

 have altered the natural temperature of the place, which is; 

 very far from all the workhigs : certainly it continues the 

 same throughout all seasons : and its expression is precisely 

 the sam^ as theory indicates. Observations 2 and 3 sho\v„ 

 that this temperature increases, as we penetrate deeper. 

 The current of air in the first galleiy, that through which 

 the ore is conveyed in wheel barrows, accounts for the smalj 

 excess of heat observed in it proportionally to. the depth. 



As to the temperature of the observations made in the 

 south part of the mine, it is visibly influenced by a foreign 

 cause, the arrival of vitriolic wtiters coming from the south, 

 On sinking a new shaft a huridred yards from the southern 

 part of the present workings, strata of aluminous schist 

 were traversed, which had a very strong styptic taste as sqon 



