VOL. XLVII.] PHILOSOPHICAL TRAWSACTIOWS. 281 



Crone-Bawn is a hill of 2 miles in circumference, and about 1000 feet in 

 height, in the form of a large inverted bowl. The bowels of this hill are full of 

 rich mines. But the principal works lie on the east side, about halfway up the 

 hill, where several shafts are sunk, fk>m 50 to 70 fathoms deep. The first mi- 

 neral met with is an iron stone. Beneath this they arrive at a lead ore, which 

 seems mixed with clay, yet yields a large quantity of lead, and some silver. 

 Under this lies a rich rocky silver ore, which sparkles brightly, and yields 73 

 ounces of pure silver out of a ton of ore, besides a great quantity of fine lead. 

 Having pierced some fathoms through this, they arrive at the copper ore ; which 

 is very rich, and may be pursued to a vast depth. 



In order to carry off the water from the mines, there are levels carried on a 

 great way under ground, from the lower part of the hill. Out of these levels 

 issue large streams of water, most strongly impregnated with copper. An ac- 

 cidental discovery, which happened not long ago, is likely to make these streams 

 more beneficial than all the rest of the mines. Some of the workmen having 

 left an iron shovel in the stream, found it some weeks after incrusted with cop- 

 per, insomuch that they thought it converted into copper. This gave the 

 hint of laying bars of iron in these streams, which is done in the following 

 manner : 



Oblong pits are dug 1 feet long, 4 wide, and 8 deep : the bottom laid with 

 smooth flags ; the sides built up with stone and lime, with wooden rude beams 

 across the pits to lay the iron bars on. Chains of these pits are continued along 

 the stream, as far as the directors please ; for the water never abates of its qua- 

 lity, if it were conveyed from pit to pit through a thousand. Soon after the iron 

 bars are laid in these pits, they contract a copper rust, which by degrees entirely 

 eats away the iron. The copper, which is in the water, being thus continually 

 attracted and fixed by the iron, subsides to the bottom of the pit. To hasten 

 this dissolution, the iron bars are sometimes taken up, and the rust rubbed off 

 them into the pit. In the space of 1 2 months the whole bar is commonly dis- 

 solved, if the iron be soft ; for steel or hard iron will not do. The stream is then 

 Jurned off the pits ; and the men with shovels throw up the copper, which lies 

 on the flag at the bottom, like reddish mud. This mud, being laid in a heap, 

 as soon as dry becomes a reddish dust. It is then smelted into copper. 



This being the apparatus, the product is thus. One ton of iron in bars pro- 

 duces a ton and IQi cwt. of this copper mud or dust. Each ton of this mud 

 produces, when smelted, l6cwt. of the purest copper, which sell at lOl. per 

 ton more than the copper which is made of the ore. There are about 500 

 tons of iron now laid in these pits ; and the proprietors may, with proportionable 

 advantage, lay in many thousands. The water that runs from these mines, 



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