1824.] Mr. Moyle on the Temperature of Mines. 449 



Most of the levels, &c. were tried in a similar manner to what 

 has just been stated, and the mud was always found to be 56°, 

 so also was the water 8 or 10 fathoms below its surface. The 

 surface of the water in this mine as well as the air never exceeded 

 59° throughout its descent, being only an increase of 3°, although 

 the water was originally 2° warmer than that of Herland, while 

 Herland increased 10° in draining to the same depth. The 

 reason for this appears to arise from the rapidity with which 

 Huel Alfred engines raised the water in comparison with that 

 of the other. Huel Alfred doing more in one month than 

 Herland did in five or six, consequently the surface of the water 

 in the shaft had less time to be exposed to the operation of local 

 causes. 



I caused two holes to be bored in the lode at Huel Trumpet 

 tin mine ; one in the end of the 80 fathoms level, and the other 

 in the 94 from the surface. They were each two feet in depth, 

 and so situated that the water should flow through them. These 

 spots were selected because they yielded the greatest quantity 

 of water, and because they extended to the greatest distance, 

 and consequently most free of all the levels from the draining of 

 the water from the superincumbent ones. The 80 extended 

 many fathoms beyond the deeper one, and yielded its water in a 

 very powerful stream through the hole. The temperature of this 

 water at the bottom of the hole was only 52°, and that at the 94 

 under similar circumstances, was 56°. A short intermediate gal- 

 lery was in full work, and no doubt influenced the temperature 

 of the water in the one below, as all the water of this gallery was 

 found to enter the ground, and doubtless filtered to the one 

 beneath. 



If further proof was required as to the similitude of tempera- 

 ture soon acquired by water, it may be found in Capt. Parry's 

 late voyage to the north, where he tried the temperature of the 

 sea at various and considerable depths. In lat. 59'26 he sunk a 

 registering thermometer to the depth of 2100 feet, and the tem- 

 perature was found to be 50J-°, precisely similar to what it indi- 

 cated at and near the surface, while the air was 53°. 



Having now adduced so many instances of temperature at and 

 near the annual mean of this climate, and that at considerable 

 depths even below the sea level, I leave it to be confuted, or 

 to have a clear demonstration why those low degrees of heat 

 should exist. 



I am, Gentlemen, your obedient servant, 



M. P. MoYtfi. 



New Series, vol. viii. 



