respecting the Temperature of Mines. 439 



are quite dry, but in general the reverse is true. Commonly 

 the water oozes almost imperceptibly from the lode and walls 

 ot the galleries, and gradually accumulates, as formerly men- 

 tioned, so as to form puddles and })ools of considerable size 

 under the feet of the miners; and it is very common to find 

 the bottom of long galleries covered, for some hundred feet 

 with dirty water of this kind to the depth of several inches and 

 sometimes of a foot or more. Sometimes, but very rarely we 

 meet with brisk streamlets or springs gushing from the lode 

 In most mines we meet with currents of water flowing towards 

 the pumps, from the uj^per galleries, or from parts of the mine 

 that have been abandoned." 



" The quantity of water in mines is most abundant durino- 

 the winter, or rather in the spring, some time after the termi- 

 nation oi the rainy season. This fact is easily accounted for, 

 especially in deep mines, by tlie length of time that the super- 

 ficial water requires to percolate to a considerable depth. In- 

 a tention to this circumstance has given rise to an erroneous 

 Idea, still prevalent among miners, that a dry easterly tj,ind 

 raises the springs. The fact seems to be, as has bee^ satis- 

 factorily shown by Pryce, that the " dry easterly winds of the 

 spring generally set in, in this country, about the period at 

 which the mam body of the rain fallen in the precedbg 

 months has been able to attain, in its slow progress throuo-h 

 the fodes and strata, the bottom of the mines*. The variation 

 m the quantity ol water is much more considerable in shallow 

 mines; these soon experiencing the variations of Immidity at 

 the surhice, according to the seasons. It is a curious fact, that 

 several imnes worked under die sea have beevi found less sub- 

 ject to the percolation of water from above, than many others. 

 1 his was formerly observable in Huel Cock in the parish of 

 ftt. Just, and IS at the present time in two mines in the same 

 parish, Botallack, and Little Bounds." 



" For keeping the ^^orkings from being inundated, each 

 mine is furnished with a chain of pumps extending from the 

 bottom to the adit-level, worked by a single pumjvrod : each 

 pump receiving the water brought up by the one immediately 

 below It Al the water of the mine, below the adit-level, 

 eventually finds its way into the bottom of the mine or sHimu 

 whence it is finally elevated to the adit, dnough which it flows 

 by a gende descent to the surfacef. The quantity of water 



discharged 



ni«f. «f P '^''^ * ^'"T^'^^'" <^"'-'"'*'>»«*; also "Observations on the Cli- 

 mate pf Penzance, &c." by John Korbes, M.D. Penzance \H2\. 



t I should have said," Dr. I'orbes observes in the imte Lcforc quoted, 



thut 



