of Capper and of Iron. ■ 309 



infpe<3;ion, the well-experienced eye of the Count de Bour- 

 non recognized a lump of it to be a mafs of femi-fufed, ar- 

 tificial, red copper ore. 



But I have found a method of producing at pleafure, in 

 the hnniid wav, all the new faltSj and the oxide above de- 

 fcnl)ed. As I had found about 11,5 per cent, of oxygen to 

 be the quantity contained in the ore, I took that quantity of 

 black oxide of copper which correfponded to 1,5 of oxygen; 

 (57,5 of black oxide was the proportion thus indicated;) o^ 

 the other hand, I took 50 parts of metallic copper, which 

 had been precipitated by inm from nnirinte of copper, and 

 which was in a Itate of tenuity not inferior to the tineii: pow- 

 jder. TJiefe were well mixed, by trituration in a mortar, and 

 .put, with muriatic acid, into a well ilopped pbial. A vio- 

 le^nt difengagcment of caloric took place; the Hquor became 

 'of the fame colour as with the ore, and contained a ialt in 

 every refpecl (Imilar to that afforded by the ore ; while a por- 

 tion of metallic copper remained, with all its luftre, at the 

 bottom of the phial. The lojution was decanted, and the 

 refiduum of metallic copper weighed 7,5. Coniequently, 

 42,5 had been dillblved, vyhich, vvith 57,5 of black oxide, 

 complete the hundred parts. 



No experiment could prove, in a manner more fatisfaftory, 

 the quantity of oxygen contained in 100 parts of this fub- 

 oxide; nor could any afford rcfults more important, or more 

 conclnGve. The pailage of a portion of oxygen from one part 

 of the metal to another, to favour its folution, as already 

 Itated, is proved beyond the poflibility of doubt; and is 

 ■doubly interelling, as it is the inverfe of wjaat happens to 

 the ore when treated by jiholphoric acid- 



In the experiments of Mr. Proutt, he has eftiraated the quan- 

 tity of oxvgcn, contained in 100 parts of this oxide, to be 17. 

 This prop(jrtion was calculated upon the deficit of a fingle 

 analytic exj>eriniC4it, made uj^oa ilie fait ot muriate of iub- 

 oxide of copper, alter having determined the quantity of acid, 

 of water, and of metallic copper. But, iird, the fait cannot 

 cafilv be obtained (as I have before obferved) in a liate futh- 

 ciently certain to be relied on, iij an experin^'iat of this na- 

 ture ; -mmX, in the next place, it is p;-obaljIe, as hapjicns in 

 alnjofi cveiv analylis, that the deficit was greater than the 

 real quantiiv of oxygen. For, the agreement between the 

 analviie. anil fynthetic experiments 1 have juli iiaied, ieenis 

 to confirm 1 1,/^ to b.e more exactly the proportion. 



When, in the dry wav, tlie nbove proportions of metallic 

 copp^T and of black oxide of cop|ver, <(r, when metallic cop- 

 per with a corrofpondiiig proportion of hydrate or of carbon- 

 i; ' ale 



