and on the interior Temperature of the Earth. 97 



stricts at least,) it gives an excess of five or six degrees for the 

 whole of the water in some shafts, which is equal to ten or 

 twelve degrees for the extreme, even supposing equal quan- 

 tities of water to flow into the shafts from the higher and lower 

 galleries : this, however, I imagine to be by no means the case, 

 but that by far the largest portion of what is emptied into the 

 adits from the overflow of the waters in shafts *, must be de- 

 rived from the upper levels and workings of mines. The 

 levels are usually driven on the veins at intervals of ten fathoms 

 under the adits ; the superior ones being more extended in 

 length than the inferior; so that they are likely to intercept 

 most of the waters coming from the ground above; and the 

 water following that course which opposes the least resistance 

 may be supposed to pass principally through the uppermost 

 levels into the shafts, and to sink therein, if its relative tem- 

 perature be low. Thus it may be presumed that the compa- 

 ratively stationary water in the deeper levels, has but little in- 

 fluence on that in the shafts; for it is well known that this 

 fluid conducts heat in a lateral direction very slowly. 



" The effects above mentioned are doubtless variously mo- 

 dified in different places by the nature and thickness of the 

 strata and the more or less pervious state of the veins : be- 

 sides, the workings communicating with the shafts are in some 

 mines much more open and excavated than in others. And 

 considering all these circumstances, we might, I think, anti- 

 cipate that the results of experiments on the temperature of 

 water in stopped mines must be discordant and inconclusive 

 as to the actual heat of the earth itself, however strongly they 

 may corroborate the truth of its existence." 



I might have added, that there are usually several shafts 

 in mines not carried down through the adit, which must re- 

 ceive large supplies of rain-water from the surface ; and this 

 water having, it may be presumed, a mean temperature less 

 than that of the climate, of course tends to diminish the tem- 

 perature of the water in abandoned mines. 



The experiments made to ascertain the temperature of the 

 ocean at great depths are, I think, quite inconclusive with re- 

 spect to the subject under consideration. The bed of the sea 

 is doubtless composed of very imperfect conductors of heat; 

 but if it were all of solid rock, it would surely be incapable 

 of transmitting heat to the water so fast as the latter would 

 convey it away, not only from its natural tendency, when heated, 

 to ascend in colder portions of that fluid, but also from the 



* The quantity of the waters so discharged from the shafts, is generally 

 considerable. 



'N. S. Vol. 9. No. 50. Feb. 1831. O incessant 



