Mr. W. Phillips's Description of hao Ores of Copper. 287 



was found in its immediate neighbourhood, and much yellow 

 coppre ore at a distance from it on the east in the vein ; about 

 8 fathoms above it was found a small quantity of gray copper 

 ore, and 3 to 5 fathoms below it, the oxide of tin occurred in 

 considerable quantity ; but no other mass in any degree resem- 

 bling this was found in any other part of the vein. It should 

 be stated that the native copper lying beside it in the vein, 

 was highly crystalline, and was coated by the substance under 

 consideration. 



To Francis Daniell, Esq. of Camborne I am indebted for 

 the information, relative to the circumstances under which 

 this singular ore of copper was found ; and to Robert Bennett, 

 Esq. of the same place, for some specimens of it, and also of a 

 very remarkable specimen of a metallic mineral found nearly 

 in contact with it. The greater part of this specimen, which 

 is about the size of a walnut, consists of a tin white metallic 

 substance, which is hard, but yields to the knife, and is ex- 

 tensible under the hammer. It is coated by the black ore 

 above described, and is accompanied by native copper, which 

 is even in some places intermingled with it, as is discoverable 

 by the assistance of a glass, on viewing a surface produced by 

 the knife : by exposure this surface acquires a tinge of yellow. 

 This substance greatly resembles that which is left on the 

 coal, as already detailed, after driving off a white vapour by 

 heat, from a fragment of the black ore; and the experiments 

 of my friend M. Faraday, Esq. detailed below by his permis- 

 sion, and which he kindly undertook at my request, render it 

 probable that each is arseniuret of copper. The black ore 

 contains occasional specks of a yellowish metallic-looking sub- 

 stance, which also I believe to be the same substance. The 

 black mineral I propose to distinguish by the name of Co7i- 

 durrite, as having been observed only in Condurrow mine. 

 It is doubtless a mere mechanical deposit, arising perhaps from 

 the natural decomposition of other ores which abounded in 

 copper and arsenic. 



Examination of the Condurrite, by M. Faraday, Esq. 



Royal Institution, July 18th, 1827. 

 When heated in a close tube, water first rises from it, then 

 arsenious acid, which condenses inapureand crystalline form; 

 and a metallic mass remains, having nearly the colour and 

 lustre of copper, but containing, besides copper, a little arsenic 

 in the metallic slate, a little sulphur, and a trace of iron. Very 

 feeble iiulicalioiis t)f the presence of a little animal or vegetable 

 matter arc observable on the first impression of heat. If this 



substance 



