1822.] Mr. Fox onthe Temperature of Mines. 441 
Poldice, a tin and copper mine, in the parish of Gwennap. 
Temperature of the water 78° in the lowest cistern, in one shaft, 
which was 144 fathoms deep. Eight men were constantly 
employed at a time, at the bottom of this part of the mine, 
besides two men, during the day (‘on tribute”). The tempera- 
ture of the water in another shaft of the same depth, and tried in 
the same way, was 80°. Two men only were employed at a 
time in the levels at the bottom. 
Consolidated copper mines in Gwennap. One shaft is 150 
fathoms deep, and the temperature of the water 76°. Six men 
were employed at a time at the bottom. The temperature of 
the water, ascertained in the same way, in another shaft, of the 
same depth, was 80°; and here there were é¢ight men at work 
at a time. 
Huel Friendship, a copper mine in Devonshire. Temperature 
of the water taken as above was 64:5° at the depth of 170 fa- 
thoms. The number of men employed at the bottom has not 
been reported ; but as they were sinking the engine shaft, there 
could not be less than two. There is, when its depth is consi- 
dered, a very small quantity of water flowing into the bottom of 
this mine ; for it requires only a six inch box, and five strokes of 
the engine a minute, to draw it up. The mine is situated on 
yery elevated ground, bordering the granite hills of Dartmoor. 
Although the temperature of the water is probably more than 
14° above the mean of the climate in which it is situated, it is 
certainly much inferior to the temperature generally observed in 
mines of the same depth. 
The undermentioned mines, being partly filled with water, I 
give the temperature of the water remaining in each. 
North Huel Virgin, a copper mine in St. Agnes parish. The 
temperature of the water, which stood at 39 fathoms under the 
surface, was 60°. ' 
Nangiles, a copper mine in the parish of Kea. The tempera- 
ture of the water at 59 fathoms under the surface was 58°. 
Nangiles is 88 fathoms deep at the engine shaft. The machinery 
for pumping the water out of this mine had very recently been 
set to work, and had consequently made but little progress in 
draining it. I mention this in connection with my remarks on 
the temperature of stopped mines, in order to account for its 
not being greater. The veins in this mine are large, and remark- 
able for the quantity of iron pyrites they contain. 
Tresavean, a copper mine in Gwennap. The temperature of 
the water standing at 100 fathoms under the surface 1s 60°, and 
the whole depth of the mine is 170 fathoms. It is situated on 
elevated ground about 480 feet above the level of the sea, and 
is moreover in granite, in which the temperature generally 
appears to be inferior to what is observed in “ killas,” or clay 
slate, at equal depths. ; 
Huel Maid copper mine. The water which it contains is ]26 
