42 Summari/ Reviexv of the late Invest igaiio7is 



Ting- Tang, the water rose considerably in the mine. On its 

 being again sunk to within 10 fothoms of the bottom, the 

 mine being 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 ob- 

 servation, was 65° : so that the water seems to have been 1-5° 

 warmer at tlie depth of 10 fathoms, than at its surface. This 

 phenomenon must, I think, be attributed to the under current 

 from the levels caused by the action of the pumps." 



" A fact, communicated to me by a gentleman in the brew- 

 house 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 siu'face, and cut 

 through the great bed of clay which lies under the metro- 

 polis. The water then rose rapidly in the well, its tempera- 

 ture 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 

 Howai'd, which is 4*5° under that of the water in the well." 



^'' I stated at the last annual meeting of this Society (Phil. 

 Mag. vol. Ixi. p. 353) that a thermometer buried at the depth 

 of 3 feet in a rock, in a level at Dolcoath mine, 230 fathoms 

 under the surface, indicated, during eight months, a tempera- 

 ture of about 75° to 75*5° 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 

 water in the undermentioned mines, at different levels, and, as 

 far as it was ascertamed, of the air also at the same stations; 

 in order to show the relative temperature of both, and the ratio 

 in which it increased in depth, widiout particularizing the 

 mines in which the experiments were respectively made ; as 

 this appears to be unnecessary." 



" The mines referred to were South Huel Towan, East 

 Liscomb, Huel Unity- Wood, Beer- Alston, Poldice, the Con- 

 solidated Mines, Huel Friendship, the United Mines, Tres- 

 kerby, Huel Uamsel, Ting- Tang, and likewise Huel Maid, 

 Nangiles, North Huel Virgin, and Tresavean. The four last- 

 mentioned mines having been partly full of water for many 

 years, the figures which refer to them are distinguished by 

 an asterisk." 



Depth 



