COPPER. ZINC, ETC. 



49 



foil, with mercury, forms the amalgam on the backs 

 of looking-glasses. 



Copper is found native, also combined with sev- 

 eral substances, such as sulphur, oxygen, the differ- 

 ent mineral acids, and several of the other metals. 

 Next to iron, it is the most indispensable to the wants 

 of man. Brass is a compound of copper and zinc. 

 Bell-metal, bronze, pinchbeck, speculum metal, &c, 

 are always of copper, with various other metals. 

 Its salts and oxides are employed as paints ; also 

 for enamelling, &c. There are many varieties of 

 copper ore, the most common of which are copper 

 pyrites, or " yellow copper ore" (a sulphuret of cop- 

 per), and the carbonate of copper, of which there are 

 two varieties, the blue and green. Copper ore has 

 been found in several parts of the United States, as at 

 the Perkiomen lead mine (Penn.), Schuyler's mines 

 (N. J.), Cheshire (Conn.), Greenfield (Mass.), Blue 

 Hills (Md.), Wethersfield (Conn.), and numerous 

 other places. The great copper-mine of Fahlun, in 

 Sweden, has been worked to the depth of 1200 feet, 

 and one of the Cornwall copper-mines (Eng.) is 

 1800 feet deep. 



Zinc generally occurs in the form of a sulphuret 

 or blende ; and is a dark brown or yellowish miner- 

 al, often occurring in fine brilliant crystallizations, 

 though more generally massive ; it is somewhat like 

 tin ore, but less heavy. 



Zinc is found in primitive and secondary rocks, 

 and is associated with sulphuret of lead, iron, and 

 copper. It is found in numerous places in the Uni- 

 ted States. 



Manganese is always found in the state of an ox- 

 ide ; it generally appears as an earthy substance of 

 a blackish colour, v hich yields readily to the knife, 

 and is sometimes soft and friable. In its metallic 

 state it has not been converted to any use ; but, with 

 muriate of soda and sulphuric acid, it forms a gas 

 called chlorine, which is extensively employed in 

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