OF ORES AND COALS. 



feam. The chief ftrata of earths and minerals obferved in this 

 mine, are blue metal ; white poll, 6 fathom ; a flaty (lone, 5- 

 yards ; and next to the coal, an hard white ftone-poft, 10 fathom, 

 and i yard. Seams of coal, of various thicknefs, lie varioufly 

 between the ftrata, not workable. There is another mine hard 

 by, of the fame quality with this. There is a dyke in it, called 

 Thiflle-pit-dyke, lying north-weft and fouth-eaft. It is believed 

 to keep a very true courfe. Many fmall dykes branch from it, re- 

 fembling the root of a tree, in different directions. 



I have had a fight of the boring-notes of fome of the other 

 mines, but they are not fufFered to come under the public view, 

 being kept as Arcana by the proprietors. 



By the beft obfervations of the mine-men, the coal-feams gene- 

 rally rife to the north-weft, and dip to the fouth-eaft. 



There are two forts of vapour terrible to men concernea in 

 coal-mines ; one fulminating, and the other arfenical ; the firft 

 volatile and a<ftive, making the candles burn precipitately, taking 

 fire, and giving an explofion like the blowing up of a citadel 

 with gun-powder, deftroying the men, and ruining the works ; 

 the other grofs and foul, not fuffering the candles to burn, in an 

 inftant extinguishing both them and the human lamp, killing by 

 its poifonous nature. On the 4th of June, 1 76 1, two overmen, 

 father and fon, of the name of Joblln, were both killed by the 

 firft in one of the mines at Byker, and remain there. In the fame 

 year, a young man was fufFocated by the latter on entering Neiv- 

 biggen-mine, but recovered by being laid on his belly, with his 

 mouth in a frefii hole made in the earth, the ufual remedy on 

 fuch occafions.' Againft this fort of vapour or damp, as it is 

 called, a large iron-lamp, full of coals, is kept continually burn- 

 ing 



