of the kilns are very long, about six feet high ; and the 
sulphur chambers are of the same length and height, con- 
nected by three flues, and on the same level with the 
kilns; four new ones, however, have been built at 
Almwch-port, by which much sulphur is preserved that 
would have been dissipated in the old kilns. The new 
ones are made like lime-kilns, with a contrivance to take 
out the roasted ore at the bottom, and thus keep up a per- 
petual lire. From the neck of the kiln branches off a sin- 
gle flue, which conveys the sulphur into a receiving cham- 
ber, built on the rock, so as to be on a level with the 
neck of the kiln, that is, above the ore. 
The two smelting-houses, of which one belongs to 
each company, contain 31 reverberatory furnaces, the 
chimnies of which are 41 feet high ; they are charged 
every live hours with 12 cwt. of ore, which yields 1-2 cwt. 
of rough copper, containing 50 per cent, of pure metal ; 
the price of rough copper is about 21. 10s. per cwt. The 
coals are procured from Swansea and Liverpool, a great 
part of which is Wigan slack. From experiment it ap- 
pears, that though a ton of coals will reduce more ore 
than the same quantity of slack, yet, owing to the differ- 
ence of price, the latter is, upon the whole, preferable ; 
the prices of the two at Liverpool being — coals 8s. od. 
per ton— slack (small coal) 5s. per ditto. 
The sulphat of copper, however, is the richest ore that 
the mine yields, containing about 50 per cent, of pure me- 
tal. This is found in solution at the bottom of the mine, 
whence it is pumped up into cisterns, like tanners’ pits, 
about two feet deep ; of these pits there are many ranges, 
each range communicating with a shallow pool of con- 
siderable extent. Into these cisterns are put cast-iron 
plates, and other damaged iron vessels procured from 
Coalbrook Dale ; when the sulphuric acid enters into 
combination with the iron, letting fall the copper in the 
