OF | ahdAY . REPORT—1857. 
965 Fahr.; the lode* was 955 and the air 95°°2: no persons at work near: 
the place. 
In a level 288 fathoms deep, another lode was 94°, the adjoining rock 
93°, and the air 91°°5: no water, and the containing rock “ hillas.” 
- Par Consols is situated near Par on the shores of the English Channel, and 
produces copper and tin in “ héllas.” Its deepest level, when visited, was 
208 fathoms from the surface, and about 178 fathoms under the sea-level: 
the lode in it was at 84°, the rock 84°, and the air 82°. ‘The part of this mine 
which produces tin was 128 fathoms beneath the surface at its deepest level, 
and there the lode was at 74°, the rock near the lode 74°, the air 75°, and 
the water 72°. 
The United Mines in the parish of Gwennap have yielded much copper 
ore in “illas.” At the eastern end of a level, 255 fathoms under the surface, 
and nearly 200 fathoms below the sea-level, a stream of water gushing out of 
a rich copper lode, called the north lode, was lately found to be at the tem- 
perature of 116° Fahr., and the neighbouring rock and air were at 106°. In 
another level, also 255 fathoms deep, worked on a parallel lode, southward of 
the former, in which there was very little water, the rock was 82°-5, and the 
air 82°. 
I have had no recent information relative to the temperature at the bottom 
of the mine, but in 1853 the rock was 94°, the air 90°, and the depth 275 
fathoms. At that date the stream of water in the eastern end of the level, 
255 fathoms deep, was at 109°, or 7° less than now that the level has been 
further extended. In 1846, when the level was still less advanced towards 
the east, the spring of water, discharging as was then estimated 94 gallons 
in a minute, was at 106°3, and the air 104°2. At that time I examined 
some of the water and found 15 grains of common salt and chloride of lime 
in a quarter of a pint of it, in nearly equal proportions; but no metallic salt 
could be detected. This mine is several miles from the sea. 
In 1853 I had some observations repeated in Tresavean, to ascertain in 
what proportion the temperature had increased with the increased depth 
since 1837. This mine is in the parish of Stythians, about eight miles to 
the N.W. of Falmouth, and has been very productive of copper, found mostly 
in granite, and but very little in killas. The bottom level was 352 fathoms, 
or 2112 feet under the surface, which is more than any other mine in Corn- 
wall, and about 1750 feet below the sea-level, or rather less in this respect 
than Fowey Consols. ‘The lode in this deep level, at its eastern extremity, 
was at 90°5, the thermometer having been long kept in a dry hole, closed 
at the top; the contiguous granite 91°5, the hole rather moist, the air 
91°-5, and a small spring of water flowing from the lode into the level, 935. 
In 1837 the deepest level in this mine was 262 fathoms, or 1572 feet beneath 
the surface, and the rock there was then found at 82°°5. 
Dolcoath, in the parish of Camborne, has been a very productive mine of 
copper and tin ores, and now yields much of the latter from its deepest parts, 
the containing rock there being granite, with killas nearer the surface. The 
deepest level on the north lode was 272 fathoms below the surface, and ex- 
tended only about four fathoms on each side of the engine-shaft. The rock 
near the eastern end of this level was at 73°5, the air 71°7, and the water 
73°, At the western end the rock was 73° on one side of the level. and 73°°5 
on the other, the air 73°, and the water, the quantity of which was very small, 
72-7, At about three fathoms further south, and the same depth, another 
* When the temperature of the rocks or of the Jodes is mentioned in this Report, it is 
meant that the thermometers were placed in holes in them for half an hour or more, and 
that the other precautions already referred to were observed. 
