Page:Transactions of the Provincial Medical and Surgical Association, volume 2.djvu/124

 the temperature is found to increase about one degree of Farenheit for every 50 or 60 feet that we descend. The following table. constructed from my journals of many painful visits to some of the Cornish mines, gives, at one view, the temperature of the air and water of six mines of this district; and the mean of the whole, given in the last column, may be considered as a correct statement of the temperature of the subterranean climate of the miner, at the various depths at which he works.

Ventilation.─The existence of this temperature at the bottom of mines, (however produced) will, of itself, necessarily occasion a constant circulation of air upwards, through the shafts; and as what ascends must be replaced by the air above, there will, of