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about one-third part of the coal is taken, and two-third parts arc 

 left to fupport the roof. 



Whitehaven colliery is not fo much loaden with water as 

 the collieries about Newcaftle and other flat countries are, where 

 they are not able, by what is called day levels, to take away the 

 top water, called furface feeds, as is pradifed at Whitehaven. 



The coal works at Whitehaven have produced and ftill do pro- 

 duce greater quantities of inflammable air, commonly called 

 damp, than any other coal work known. This feems to arife 

 from the coal lying at a greater depth below the level of the 

 fea than any other known colliery. This obfervation holds inva- 

 riably true both here and about Newcaftle, that in all coal works 

 lying above the level of the fea little or no inflammable air is 

 perceived, except in the guts of the dykes, that is, in the cavi- 

 ties or hollows betwixt the fields of coal and the dykes or beds 

 of ftone which feparate the fields. The quantity of inflamma- 

 ble air appears to bear proportion to the depth of the works 

 below the level of the fea. 



When they began to fink the coal pits at Whitehaven fo 

 deep that coals were drawn from below the level of the fea, in- 

 flammable air was found in fuch quantities that it frequently 

 took fire from the flame of the candles ufed by the workmen 

 under ground, which caufed violent and dangerous explofions, by 

 which numbers of the workmen were burned and maimed, and 



by 



