Vcmstones. 



The ore dC' 

 icribed. 



AXAI'YSIS OF A CUAY ^OPPER ORK. 



pauies. But, in both ca-cs, was nbniKJoned, after a ft \v 

 years ttiul. 1 went to it some years ago, ami examined the 

 ore, at tlie recjuest of one of tl)e propiictors. The speci- 

 mens, which were employed for the sul>seqnent analysis, 

 were the purest tJiat I conld select out of a considerable 

 quantity. I was tohl, however, that from the lower level, 

 which was at that time full of water, much richer ore had 

 been extracted. But, afterward, when the lower level was 

 freed from its water, I went down to it mysetf, and found 

 the ore precisely of the same kind as in the upper, with 

 this difference, that it was more mixed with a calcareous 

 spar, and perhaps, on that account, more easily smelted. 



The veinstones in the Airthrey mine are sulphate of 

 barytes, and carbonate of lime, and with these the ore is 

 almost always more or less mixed. 



The colour is at first a light steel gray ; but the surface 

 soon tarnishes, and becomes of a dark dull leaden gray, and 

 in some places assumes a beautiful tempered steel tarnish. 

 Massive and disseminated. J n some specimens, it exhibits 

 the appearance of imperfect crystals. Internal surface 

 shining and metallic; but, by expo>;ure, it soon becomes 

 dull. Fracture small grained, inclining to even. Frag- 

 ments indeterminate, and rather blunt edged. Semihard, 

 the degree being almost the same as that of calcareous 

 spar ; for these two niinerals reciprocally scratch each 

 other. Streak similar, opake, brittle, easily frangible, spe- 

 cific gravity 4-878. w...,-; lui 



1. To free the ore as completely as possiDlefrorii' foreign 

 matter, it was reduced to a coarse powder, and carefully 

 picked. It was then digested in diluted rnuriatic acid, 

 which dissolved a quantity of carbonate of lime, amounting 

 to 13 per cent of the original weight of the ore. 

 then analysed. ' 2. Thus purified, it was dried on the steam bath, and 

 100 grains of it were reduced to a fine powder, and di- 

 gested in diluted nitric acid, till every thing soluble in that 

 menstruum was taken up. The residue was digested in 

 the same manner in muriatic acid; and when this acid 

 ceased to act, the residue was treated with iiitro muriatic 

 acid, till noi farther solution could be produced. The insolit- 

 ble matter was of a white colour; it SveigHedG'CfgVffins, 



and 



The ore first 

 picked, 



