A TOUR ROUND NORTH WALES. 283 



gloves. It is then piled in kilns of great 

 length, and about fix feet high, and fet on 

 fire in different places to undergo the pro- 

 cefs of roafting ; for as the ore in it's natu- 

 ral ftate contains a great quantity of ful- 

 phur, it is neceflary that this mould be fe- 

 parated from it by roafting, before it can be 

 fluxed into copper. The fulphur fublimes 

 to the top of the kiln, from whence it is 

 conveyed by a flue connected with it to the 

 fulphur chamber, a place built to receive 

 it, where it condenfes, and becomes the 

 flowers of fulphur of the {hops. It is af- 

 terwards taken from hence, melted in large 

 copper pans, and caft in moulds for fale. 



After the ore has been thus roafted, 

 which is rather a tedious operation, taking 

 from three to ten months, according to the 

 quantity in the furnaces, which is gene- 

 rally from three hundred to a thoufand 

 tons, it is taken to the flacking pits, places 

 conftru&ed of ftone, about fix yards long, 



five 



