1822.] Mr. Fox on the Temperature of Mines. 443 
months suspended; an opportunity occurred for ascertainin 
the temperature of the water, when it was sunk to the depth of 
126 fathoms under the surface, and was only 10 fathoms deep, 
in the bottom of the mine. It was then found to be ‘63°, and 
this was before many men had resumed their labours, or indéed 
any of them, at the inferior levels ; and moreover, at the time of 
making the observations, even the few men who worked in the 
mine had not been in it for the space of nearly two days. 
Near the middle of 1819, when the water stood at the same 
place in the mine, and it was, and had long been, in a state of 
full working ; the temperature of the water at the bottom was 
only 59°. Perhaps the water will again be reduced to this tem- 
perature, ifit should remain at the same depth in the mine ; for 
is not reasonable to suppose, that the droppings of colder water 
down through the shafts must affect the temperature of that at 
the bottom ? 
In consequence of an accident in the steam-engine at-Ting 
Tang, the water rose considerably in the mine. On its being 
again sunk to within 10 fathoms of the bottom, the mine heing 
117 fathoms deep, its temperature at this station was found to 
be 63:5°; whereas the water pumped up from the bottom into a 
cistern immediately above the place of observation was 65°; so 
that the water seems to have been 1-5° warmer, at the depth of 
10 fathoms, than at its surface. This phenomenon must, I think, 
be attributed to the under current from the level caused by the 
action of the pumps. 
A fact, communicated to me by a gentleman in the brewhouse 
of Barclay and Co. at Southwark, may here be noticed. Not 
long ago, a well was sunk, in order to procure water for the 
supply of the brewery. They did not attain their object, until 
they had got down 140 feet under the surface, and cut through 
the great bed of clay, which lies under the metropolis. The 
water then rose rapidly in the well, its temperature being 54°, 
which it invariably maintains at all seasons of the year. Now 
the climate of London and its vicinity is at the mean temperature 
of 49°5° on the authority of Luke Howard, which is 4°5° under 
that of the water in the well. 
I stated at the last annual meeting of this Society that a 
thermometer buried at the depth of three feet in a rock ina 
level at Dolcoath Mine, 230 fathoms under the surface, indi- 
cated, during eight months, a temperature of about 75° to 755°, 
when the mine was clear of water. It has subsequently remained 
in the same place nearly twelve months longer, and the mercury 
has continued stationary at 75°5°, notwithstanding the changes 
of the season. 
Although, I think, it will be admitted, that the bottoms of 
our mines are, for many reasons, less liable to be influenced by 
adventitious causes than the superior levels, I shall give the 
results of various observations made on the temperature of 
