262 ANNUAL OF SCIENTIFIC DISCOVERY. 



ganese, and copper, and is evidently the result of their decomposition. 

 The oxide of copper found at Copper Harbour is generally compact, 

 though the purer specimens have a crystalline structure. Some speci- 

 mens' are almost chemically pure, though it is generally mixed with a 

 little silicate of copper. One of the purest specimens contained only 

 1.2 per cent, of impurities, mostly silica, with traces of lime and iron. 

 As the oxide of copper of this remarkable vein has not been minera- 

 logically described, the following description is added. Crystallized 

 in cubes, with their solid angles occasionally replaced; generally, 

 however, massive, with crystalline structure, sometimes earthy ; no 

 traces of cleavage ; H 3 ; G = 6.25 ; color, steel-gray to black ; lus- 

 tre metallic, the earthy varieties acquire a metallic lustre on being 

 scratched or cut with a knife ; opaque. Chemical composition Cu. O. 

 almost pure; containing copper 79.86, oxygen 20.13. Proc. Bost. 

 Soc. Nat. Hist. 



Among the masses of black oxide of copper brought from the mine 

 at Copper Harbour, Mr. J. E. Teschemacher discovered regular cubic 

 crystals of the ore, crystals which show that the ore is not a mere me- 

 chanical mixture of copper smut with earthy matters for a cement, as 

 some have supposed. There are also found at the Copper Harbour 

 mine, chrysocolla, or hydrous green silicate of copper, and the black 

 silicate, which contains a less proportion of water. These ores, we 

 can easily conceive, might be produced by the decomposition of a so- 

 lution of copper by the action of a hot solution of lime. The black 

 oxide may have been derived either from a solution, or from igneous 

 sublimation. We know that black oxide of copper is sublimed from 

 the crater of Vesuvius, and is, deposited in fine splendent scales, like 

 specular iron ore in the lavas. Proc. American Association. 



ON THE EXISTENCE OF VANADIUM IN THE COPPER ORES OF 



LAKE SUPERIOR. 



DURING the course of the past year, Mr. J. E. Teschemacher, of 

 Boston, having noticed the presence of a dark-colored mineral among 

 some ores of copper brought from Lake Superior, submitted the same 

 to a chemical analysis. The result showed the presence of vanadic 

 acid in considerable quantity. A discovery so unlocked for caused a 

 suspicion of error, and the substance in question was submitted to a 

 distinguished chemist for further examination and analysis. The re- 

 sult coincided with that obtained by Mr. Teschemacher, and proved 

 beyond all doubt that vanadium exists in some of the ores of copper 

 found near Lake Superior. The manner in which it is disseminated 

 through the specimens analyzed affords a strong presumption that it 

 will be found hereafter in considerable quantities. Vanadium was 

 discovered in 1830 by Sefstrom, in iron prepared from the iron ore of 

 Taberg, in Sweden. Soon after Sefstrom's discovery, the same metal 

 was found by Johnson of Enland in combination with lead, and form- 

 ing a vanadiate of lead. A similar mineral was found at Zimapan, 

 Mexico, in 1801, by Prof, del Rio. He supposed it to be a new met- 

 al, and applied the name erythronium, from the red color of its acid ; 



