18!^6.][ Mr. Moyle on the Temperature of Mines. 25§ 



metal can scarcely be in excess ;* as the rapid motion of these 

 ships prevents the chance of any adhesions ; and the wear of 

 the copper by proper protection is diminished more than two- 

 thirds. 



Article V. 

 On the Temperature of Mines. By M. P. Moyle, Esq. 

 (To the Editors o{ ihe Annals of Philosophy/.) 



GENTLEMEN, Hclston, March 1, 1826. 



Having done me the repeated favom' of inserting -my com- 

 munications on the much disputed question as to the heat of the 

 internal strata of the earth, 1 have to beg a continuance of your 

 kindness in giving place to the following facts in continuation 

 of that subject. 



In the first place it may be necessary to state, that during the 

 last summer and autumn, I repeated most of my former experi- 

 ments on the water in the old and relinquished mines as before 

 stated (vide Annals, vol. v. N. S.)j and almost precisely with the 

 same results. Suffice it to say on this head, that the greatest 

 heat found in those collections of water from the depth of 20 to 

 170 fathoms from the surface was 55° Fahr. in Relistian mine, 

 in the parish of Gwinear, while the coldest temperature found 

 was 52° at 134 fathoms in Huel Ann, in Wendron, 



I conceived that by selecting a stagnant collection of water in 

 a deep part of a mine at work, the temperature of which spot 

 while it was occupied by the workmen was known, might more 

 effectually give us the true temperature of the surrounding 

 strata, than by any other means. I, therefore, selected a winze\ 

 at the 1 10 fathom level, in Huel Trumpet tin mine, in the parish 

 of Wendron. This winze was sunk between four and five 

 fathoms, when it was found necessary to relinquish it from the 

 water being too quick ; and until the 120 fathom level was driven 

 far enough under it to drain it of its water. 



A bole was bored in the sohd granite at the bottom of this 

 winze two feet deep ; a thermometer was put into it, and the 

 hole was soon found to fill with water from a natural infiltration 

 without a drop falling into it from above. As this hole filled 

 with water, the thermometer fell to 56°, but in a few hours it 



• I have mentioned in the two last communications on this subject some applications 

 of the principle; many others will occur. In submarine constructions — to protect wood, 

 as in piles, from the action of worms, sheathing of copper defended by iron in excess may 

 be used ; when the calcareous maf.er deposited will gradually form a coating of the 

 character and firmness of hard stone. 



+ A winze is a small shaft sunk simply from one level to snQther, often rccjulced for 

 ventilation, as well as for the judicious worlcing of amine. 



s2 



