446 Mr. Fox onthe Temperature of Mines. [Dec. 
charged was equal to 1400 cubic feet per minute, or about 
60,000 tons per day. ) . 
The great adit is divided into three principal branches, the 
first of which unites with it, at about a mile from its mouth, and 
communicates with the United and the Consolidated Mines, 
Huel Squire, Ting Tang, Huel Maid, and South Huel Jewel, the 
average depth of which mines seems to be about 150 to 160 
fathoms. ‘The temperature of the water in this branch near the 
junction, and about one mile and a half from the mines which 
principally supply it with water was 73-5°, about the end of last 
month, when this and the following observations were made, 
At nearly a mile further on, the great adit is divided into two 
branches ; one of them receives the water from Poldice, Huel 
Unity, Huel Unity Wood, Huel Damsel, Huel Purk, Rose 
Lobby, Huel Hope, Huel Gorland, Huel Jewell, and Huel Clinton, 
the average depth of whichis, perhaps, from 110 to 120 fathoms, 
and the temperature of the water in the branch, at about a mile 
from the principal mines above named, was 66°5°. 
The other branch is connected with Treskerby, Huel Chancer, 
Chacewater, North Downs, Creegbraws, Huel Boys, Cardrew, and 
a few smaller mines ; their average depth may be estimated at 
100 to 110 fathoms, and the temperature of the water in the adit, 
about three miles and a half from the mines, was 65°. 
I have not ascertained the quantity of water discharged by 
each of these branches ; bat it is evident they carry off not only 
the water pumped from the various levels of the respective mines, 
but also that which is drained from the strata under which they 
pass, and which is from 30 to 50, and in some places from 60 to 
70 fathoms in thickness. 
The temperature of the water in the adit is, therefore, even 
more considerable than might be expected, and the difference 
observed in the branches may be attributed to the relative 
depths of the mines with which they are connected, and to many 
of those communicating with the two last mentioned branches 
being stopped, or partly full of water. 
I have mentioned that the water flows into cisterns at different 
levels in mines, being partly or entirely retained by the rock on 
which it rests, but generally from the strata being more or less 
porous, some of the water sinks through it, and may either mix 
with an inferior portion, before it flows into the levels, or it some- 
times descends in numerous drops, or small streamlets, from the 
roofs of deeper levels; and in either case, it must produce more 
or less influence on the temperature, and prevent its being uni- 
form at equal depths. 
If there were a perfectly free and open communication between 
the various portions of water under the surface of the earth, it 
is evident that mines could not be drained, but-the pressure of 
the columns of water would be irresistible, and their impetuosity 
overwhelming. 
