DURHAM AND NORTHUMBERLAND. 2<)*

great quantities; and though many opinions pre-vail relative to the manner in which carburetedhydrogen is generated in a mine, one alone existsas to the destruction it causes when exploded.There is no doubt that it proceeds from the bedsof coal in the greatest measure, and from therents or fissures wherein it is frequently pent,and either exudes in gaseous volumes throughthe coal, or hursts out in streams of foul air,so that the miner is generally exposed to thegreatest danger even in the common workingof a colliery, although hardiness and habitude

remove fear, and even in many instances cau-tion, far from his considerations.

Mr. Dalton has shown (see his work) thatthe fire-damp of mines is the same as is pro-duced in wet marshes ; and society are indebtedfor a corroboration of this opinion to the va-luable experiments of Sir Humphrey Davy,*who has elucidated its many peculiar qualities,and shown the great degree of its inflam-mability.

Very few mines are so free from gas as notto be in some measure dangerous; for the at-

* See his Paper as printed in the Philosophical Transac-tions for 1815, and in Tilioch’s Philosophical Magazinefor January 1816.