36 Mr. Moyle on the Temperature of Mines. [Jan. 



below the level, 66° ; and at 12 fathoms, as before, deep in the 

 water, 67° ; it having cooled 3° in a fortnight, and 11° since its 

 admission into the shaft. 



In Crenver copper mine, very little work has been done for a 

 great while. At 300 feet, and 300 feet east of the engine shaft, 

 the temperature was 56° ; at 432 feet deep, 56° ; at 492 feet, 

 61°; at 617 feet, 62°; at 672 feet, 64°; at 732 feet, 64° in the 

 shaft ; but in a gallery 360 feet east, only 60° ; at 792 feet, 63° 

 in the shaft ; but 1200 feet east of it, only 61° ; at 852 feet, 62° ; 

 but at 180 feet west, it was 64° ; and at 1200 feet west, it was 



68°. 



Huel Abraham is on the same lode as Trenoweth, Crenver, 

 andOatfield; and is, in almost every part, in full work. At 

 1332 feet below the surface, the temperature was 84°. At 1392 

 feet deep, at the extremity of the level, on a Monday morning, 

 before the workmen had returned to labour, and where a machine 

 was erected for blowing fresh air to the miners, the thermometer 

 stood at 90° ; but a few days afterwards, when a communication 

 had been formed, it fell to 86°. At the depth of 1452 feet, it 

 was, in one gallery, 84° ; and in another (the only spot where 

 there were no workmen), it was 86°. 



I shall now mention the result of some experiments, to ascer- 

 tain the temperature of the water, at different depths, in mines 

 which have been long abandoned. 



Herland copper mine, in Gwinear, has ceased working (except 

 above the adit), 15 years. On the 28th May, 1822, while the 

 temperature in the shade at the surface was 64°, and in the sun 

 74°, I found that of the water running through the adit, 32 

 fathoms deep, 52° ; as we approached the engine shaft, it was 

 increased to 53° ; and on sinking two self-registering thermo- 

 meters, properly secured in a box with iron weights, the temper- 

 ature, at the depth of 10, 20, 40, 60, and 100 .fathoms in the 

 water, and 792 feet from the surface, was uniformly 54°. In 

 another shaft in this mine, 360 feet north-west of the great 

 engine shaft, the water running through the adit v/as 54° ; and 

 at 10, 20, and 40 fathoms deep, 56°. 



On the 8th of June, 1822, I visited Huel Poel and Huel Rose 

 lead mines near Helston. In the former, the temperature of the 

 water, at 10 and at 20 fathoms deep, was 53°. In another shaft 

 it was precisely the same. 



In Huel Rose, the water in the engine shaft was, at 60 feet 

 deep, 53i-°; at 120 feet, 53-1° ; at 240 feet, 534-°; and at 300 

 feet, only 53°. The time allowed for the thermometer to remain 

 at the different depths (except the last) was 10 minutes, which, 

 perhaps, was scarcely long enough. 



In Huel Alfred (visited in July, 1822), the temperature of the 

 water in the adit, 18 fathoms below the surface, was 56% and at 

 the several depths of 60, 120, 240, 360, 600, and 672 feet of 

 water, or 780 feet from the surface, it was uniformly the same. 



