106 



On the Temperature of Mines. 



" The following table presents at one view the temperature 

 of air and water in the deepest coal-mines in Great Britain." 



" It has been found from experience, that the deeper we 

 perforate the strata, they become drier, and in many histances 

 no water is to be found, so that the roads through the mines 

 require to be watered, in order to prevent the horse-drivers 

 from being annoyed by the dust ; and there is reason to be- 

 lieve, that the high temperature of the air in Prince's-end pit, 

 was occasioned by the decomposition of pyrites amongst the 

 rubbish of the coal, which frequently produces actual and ve- 

 liement combustion. The increase of temperature, as given 

 in the preceding experiments, a}>pears to have its origin in a 

 constant natural internal heat in the physical constitution of 

 the earth." 



" It has been asserted by those who have considered the 

 temperature of mines that the heat found there arises from 

 the workmen, and from the lights and horses employed in the 

 mines. These causes, however, cannot produce more than a 

 degree or two of temperature, as the air is necessarily kept in 

 constant circulation for the safety of the workmen." 



* Springs. f " Air in the mines 60°." t " In a country a 



little elevated above tlie sea." § Estimated from the level of the 



ocean, « and beneath the waters of the Irish Sea." 



II The depth reckoned from the level of the sea, " and under the bed of 



«"y7- ^"1' ^* ^'"^ ''"^P''^ Leslie's hygrometer indicated dryness 83°." 



1 Air at the pit botto n 64° ; the engine pit of Jarrow is the deepest 



perpendicular shaft in Great Britain, being 900 feet to the foot of the pumps." 

 ** Alter the air has " traversed IJ miJe from the bottom of the downcast 



pit. -|-j- " At the most distant forehead or mine This mine is 



tne deepest coal mine in Great Britain ; in fhis mine the temperature of 



uistilled water at the boiling point was 213°,; the temperature of the same 



water at the surface 21 Or.' 



« Others 



