218 
Mr. Weaver on the 
cwt. 2 qrs. of copper. Hence, the aggregate produce from the 
commencement to that period was 26,875 tons, 13 cwt. of ore, 
average produce 6yy per cent, equal to 1717 tons, 1 cwt. 2 qrs. of 
copper. 
In the year 1808, the ore raised was 2576 tons, 14 cwt. At this 
period the produce of copper mines suffered a great depreciation in 
the market, from which it has not since recovered. Hence in the 
subsequent years, the ore raised at Cronebane has not exceeded a 
few hundred tons. 
§ 115. The mineral waters flowing both from the upper and 
lower mines are impregnated with sulphate of copper. These waters 
are received into tanks, in which the muddy particles are allowed to 
subside. The clear waters are then passed into pits filled with plate 
and scrap iron, which causes a precipitation of the copper. In this 
manner 442 tons, 11 cwt. 3 qrs. of this precipitated copper (mixed 
with oxide of iron) have been obtained, which sold on an average 
for 271. 8s. 9d. per ton, being in aggregate value 12,1261. 18s. l|d. 
while the consumption of iron was only 429 tons, 14 cwt. or less 
than one ton of iron to the ton of precipitate, being in aggregate 
value 26201. 18s. 8d. 
§ 116. Sulphur was extracted on the spot from the copper 
pyrites, obtained from the mines, by the following process : the ore 
broken into fragments of the size of large walnuts, and freed from 
smaller particles, was placed in low cylindrical kilns with a flat 
bottom, capable of holding fifty or sixty tons of ore. On the oppo- 
site sides of the kiln were four apertures, and these were connected 
across the bottom of the kiln by open flues of bricks. On the flues 
was placed a layer of heath and furze; the kiln was then filled, 
and on the top of the ore was constructed a cross close flue, which 
led to an arched receiver sixty or seventy feet in length, four feet in 
