REVIEWS. 



403 



portions were long since made public by the various newspapers and the periodicals 

 at the time of the meeting, and the report itself appears somewhat wanting in 

 novelty, like the detailed dispatches following long after the rapid information 

 of the telegraph. To revioAV it at length would require more space than we could 

 afford, but it would not be granting it more than its deserts ; we shall, however, 

 content ourselves with noticing more particularly the geological portions. The 

 report on the Temperature of some deep Mines in Cornwall, by Mr. Robert Were 

 Fox, is an addition to the evidences on an obscure, but highly interesting, point. 

 The "bearing" of the Cornish metalliferous lodes is generally and ordinarily 

 from northward of east to southward of west, and they commonly descend into the 

 earth to unknown depths in an inclined direction ; the working of the lodes being 

 effected by means of shafts and galleries or levels. The water is pumped up the 

 engine shaft, from the bottom or sump, up to the adit, from which it is dis- 

 charged into a valley or near the sea-shore. 



The cross-cuts, or north and south levels, connect the engine-shaft with the levels 

 at right angles to them. These latter, or the course of the lode, are usually about 

 ten fathoms apart, and are connected together by many short shafts inclined into 

 the lode. There are also other shafts from the surface to the deep levels, through 

 which the ore is drawn up, and the ventilation of the mine effected In most of 

 the deep mines several lodes are simultaneously worked, each by a similar series 

 of shafts, levels, &c., which are connected with the former series by cross-cuts, so 

 that one engine may serve for two or more lodes. The deepest levels in a mine 

 are generally much less extended than those above them, and the quantity of 

 water is often comparatively small, the upper water being in a great degree cut 

 off by the superior levels, and conveyed to the cisterns through the latter. The 

 temperature of the water that flows into the ends of the deepest levels is generally 

 as high, or nearly so, as that of the rocks and lode, and more often higher ; which 

 it may be presumed it could not be, if much of the upper water were mixed with 

 it. Most of the experiments were made at or near the ends of the deepest levels, 

 in each of the respective mines. 



The thermometers employed were placed in holes 15 or 20 inches deep in the 

 rocks and lodes, and were carefully closed up with clay, tow, or cotton, and, after 

 the thermometers had been thus left from half an hour to an hour, they were 

 withdrawn and read off. In taking the temperature of the water, the most 

 copious springs at their sources or influx into the levels were selected, if near the 

 stations where the other observations were made ; and the temperature of the 

 surrounding air was also ascertained. The mines visited were situated in different 

 parts of the county, ranging over fifty miles of country, from Fowey to St. Just, 

 near the Land's End. 



The following is an epitome of the results 



Fowey Consols Copper Mine — deepest level 328 fathoms from surface, 298 below 

 the sea. At 268 fathoms from surface, water issued from a copper-lode at 96" 5' 

 Fahr., the lode was 95" 5\ No persons at work near the place. At 288 fathoms, 

 another lode was 94° ; the adjoining rock killas 93" ; the air 91° 5'. Par Consols 

 Mine produces copper and tin in killas. Deepest level 208 fathoms from surface, 

 179 under sea-level ; temperature of lode 84° ; rock 84° ; air 82°. The part of 

 this mine which produces tin was 128 fathoms beneath the surface at its deepest 

 level ; the lode there was 74^ ; the rock 74'^ ; the air 75*=' ; and the water 72". 



The United Mines, in the parish of Gwennap, yield copper-ore in killas. At the 

 eastern end of a level 255 fathoms under the surface, and nearly 200 fathoms 

 below the sea level, a stream of water from a copper-lode gave 116*^ Fahr,, while 

 the neighbouring rock and the air were at 106°. In another level, also at 255 

 worked on a parallel lode, south of the former, in which there was very little 

 water, the rock was 82° 5^ and the air 82°. 



In 1853, Mr. Fox repeated some observations in the Tresavean Mine (situated 

 about eight miles north-west of Falmouth) to ascertain in what proportion the 

 temperature has increased with the increased depth since 1837. The mine has 

 been very productive of copper, found mostly in granite and but very little in 

 killas. The bottom level, deeper than any other in Cornwall, was 352 fathoms, or 

 2,112 feet under the surface, and about 1,750 below the level of the sea. The 



