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, ii 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 v^hich there are 
two varieties, the blue and green. Copper ore has 
been found in several parts of the United States, as at 
the Perkiomen leadmine (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 ihe 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, vhich yields readily to the knife, 
and is sometimes soft and friable. In its metaUic 
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 
