368 Tlejcriplion of the Anglifey Copper-Wofls. 



from below ; and at (Viort intervals is heard, from diiTcrcnt quarters, the loud explofion of 

 the gunpowder by which the rock is blafted, reverberated in pealing echoes from every fide. 

 1 he exterior covering of the mountain is an aluminous flate ; the matrix black-grey 

 chart2 ; the ore copper, chiefly 



I. Tki stUoiv Julphurattii : of which the richeft contains, according to miners' computa- 

 tion, that is, in the proportions of the ounce troy, 



Sulphur 5 ^'«''- ('S per cc"t.) 



Copper — Ditto. 



Rcfufe 10 dwt. (so per cent.) 



The word ore yields nearly the fame quantity of fulphur, but of metal no more than (ix 

 trains (ij per cent ) ; this inferior kind, however, is chiefly worked for the fulphur. The 

 Other fpecies and varieties of ore that the mine produces are, 



II. Black ore, containing copper, mixed with galena, calamine, and a little filver. 



III. Malachite, or green and blue carbonate of copper. 



IV. Native copper, but in very fmall quantity. 



V. Sulphate of copper, cryftallized and in folution. 



VI. Sulphate of lead in confiderable quantity, containing a pretty large proportion of 



filver. 



VII. Native fulphur. 



Procefs. — The ore is got from the mine by blading ; after which it Is broken Into fmaller 

 pieces by the hammer (this being chiefly done by women and children), and piled into a 

 kiln, to which is attached by flues a long fulphur chamber. It is now covered clofe ; a 

 little fire is applied in different places, and the whole mafs becomes gradually kindled ; the 

 fulphur fubli.Ties to the top of the kiln, whence the flues convey it to the chamber appointed 

 for its reception. This fmouldering heat is kept up for fix months, during which the ful- 

 phur chamber is cleared four times, at the expiration of which period the ore is fufficiently 

 roafted. The pooreft of this, that is, fuch as contains from li to 2 per cent, of metal, is 

 then conveyed to the fmelting-houfes at Amlwch-port ; the reft Is fent to tjie company's 

 furnaces at Swanfea and Stanley near Liverpool. The greater part of the kilns are very 

 long, about fix feet highj and the fulphur chambers are of the fame length and height, 

 connefted by three flues, and on the fame level with the kilns ; four new ones, how- 

 ever, have been built at Amlwch-port, by which much fulphur is prcferved that would have 

 been dilTipated in the old kilns. The new ones are made like lime-kilns, with a contri- 

 Tance to take out the roafted ore at the bottom, and thus keep up a perpetual fire. From 

 the neck of the kiln branches off a fingle flue, which conveys the fulphur into a receiving 

 chamber, built on the rock, fo as to be on a level with the neck of the kiln, that is, above 

 the ore. 



The two fmelting-houfes, of which one belongs to each company, contain 3 1 reverbcratory 

 furnaces, the chimnies of which are 41 feet high ; they are charged every five hours with 

 12 cwt. of ore, which yields \ cwt. of rough copper, containing 50 per cent, of pure metal; 

 die price of rough copper is about 2I. los. per cwt. The coals are procured from Swanfea 

 and Liverpool, a great part of which is Wigan flack. From experiment it appears, that 

 though a ton of coals will reduce more ore than the fame quantity of flack, yet, owing to 



tlie 



