45 
Copper . 
form of a red sediment very slightly oxided. The cis- 
terns are cleared once in a quarter of a year, when the 
sulphat of iron in solution is let off into the shallow pool? 
and the copper is taken to a kiln, well dried, and is then 
ready for exportation. The sulphat of iron remaining in 
the pool partly decomposes by spontaneous evaporation, 
and lets fall a yellow ochre, which is dried and sent to 
Liverpool and London. 
The sulphur produced in the roasting, after being melt- 
ed and refined, is cast into rolls and large cones and sent 
to London. The cones are used chiefly for the manufac- 
tory of gunpowder and sulphuric acid. 
Green vitriol and alum are also made in small quantities 
by a separate company ; but to these works strangers are 
not admitted. 
The number of men employed by the two companies 
is 1200 miners, and about 0 smelters ; the miners are 
paid by the piece, and earn in general from a shilling to 
twenty pence per day. 
The depth of the mine in the lowest part is 50 fathoms? 
and the ore continues as plentiful as ever, and of a quality 
rather superior to that which lay near the surface. 
With regard to the annual quantity of ore raised, little 
certain can be mentioned. The Parys mine has furnish- 
ed from 5000 to 10,000 tons per quarter, exclusive of 
what is procured from the sulphat of copper in solution ; 
and as the two mines employ nearly equal numbers of 
workmen, they probably afford about the same quantity 
of ore. 
Adjoining to the smelting-houses is a rolling-mill, up- 
on the same construction as malt-mills, for grinding the 
materials for fire bricks ; these consist of fragments of 
old fire-bricks, with clunch (a kind of magnesian clay 
found in coal-pits) procured from near Bangor-ferry. 
The port of Almwch is chiefly artificial, being cut out 
