74

COAL MINES OF

shaft sunk for that purpose at the lower end ofthe dip.

When a seam of coal is in work whieh hap-pens to be above another some time workedout, the waters are easily drained oft' by suf-fering them to descend and accumulate in theold wastes of the lower seam ; and it is thiscircumstance which renders it so necessary tohave correct records of the boundaries, asshould they be broken through, the adjoiningmine is deluged and the workmen drowned.

During- the progress of cutting a shaftthrough the soil to a stratum of coal, machinesare erected above the pit, and every apparatusprovided which may be necessary to the ulti-mate process. When digging commences in adistrict where no pits have before been sunk, thechange of aspect is surprising: the immediatevicinity is soon covered over with machinery,huts, and different habitations, and the countryintersected with staiths or waggon-ways.

The miner, having come to his stratum, digsfirst to the bottom, and then proceeds to workhis way through it; in the higher seams thecoals are drawn by horses from the hewers tothe shaft in sledges, and in the lower onesthey are drawn in the same manner on trams,*

* Tram is a kind of basket made very large and strong,and fixed on a sledge for the purpose of being drawn.