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XLVI. Dc&criptio7i of tiw 7-emarkable Ores of Copper from 

 Cornvaall. By William Phillips, F.L.S. F.G.S. S(c.* 

 With an Analysis of the same, by M. Faraday, F.R.S. ^c. 



AMASS consisting of a few hundred pounds weight of a 

 very singular kind of copper ore, was lately found in a 

 vein in Condurrow mine, which is situated in granite, and 

 about half a mile south of the old and celebrated copper mine 

 called Dolcoath, which is near to Camboi-ne in the county of 

 Cornwall. 



In the aspect of the mass in question there is nothing indi- 

 cating its being constituted for the most part of copper, for it 

 bears no analogy in appearance to anj' of the known ores of 

 that substance; its great weight, however, induced the trial, 

 and some parts of it were found to contain 64^ per cent of 

 that metal, others yielded less copper, and were less heavy ; 

 some, having the same aspect, were quite light; the specific 

 gravity of the portion analysed, as hereafter detailed, was S'SOIS, 

 as taken by my friend S. L. Kent, F.G.S. : the greater part of 

 the mass was broken up and mingled with other ores of 

 copper. 



The general colour is brownish-black, sometimes present- 

 ing however a tinge of blue. A specimen in my possession, 

 which was broken from the mass immediately on its discovery, 

 presents a flat conchoidal fracture, and a highly polished black 

 surface; but, having parted with much of the water it contained 

 when first broken in the vein, owing to exposure, it is now 

 cracked in various directions, as are all the specimens I have 

 seen, and readily divides into irregular portions very much 

 resembling those of starch : these portions are covered by a 

 blackish-brown powder which soils the fingers ; on its remo- 

 val, the surface of the portion sometimes has a slightly bronzed 

 appearance. It is hard, but not sufficiently so to scratch 

 glass ; is brittle ; yields to the knife, which leaves a polished 

 metallic-looking surface, nearly of a lead gray colour. When 

 powdered it is soot-black, A fragment placed on a red hot 

 coal when in the fire, shortly afforded a copious white vapour, 

 leaving on the coal a metallic substance in a semi-fluid state, 

 of a yellowish colour. 



The mass of copper ore was found 65 fathoms under the 

 surface of Condurrow mine, alone in the vein, or rather, un- 

 mixed with other metallic ores : beside it lay a mass of native 

 copper weighing about 1 50 pounds ; and about half a ton more 



* Communicated In tlie Author. 



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