8o 
States, Canada, New Caledonia, and other localities, and is used 
extensively in the manufacture of alloys for electroplating and 
coinage. 
IRON. 
Cases I, J, K, L, lO, and 17 . — Iron Ores. 
The richest iron ore minerals are: Magnetite (black oxide of 
iron), containing, when pure, a little more than 72 per cent, metallic 
iron; Hematite (red oxide of iron), containing 70 per cent, of 
iron; Limonite (brown oxide of iron), containing 60 per cent, of 
iron; and Siderite (carbonate of iron) which contains about 48 per 
cent, of iron. 
Manganese. 
Cases 18 and lO. — Manganese Ores. 
The manganese mineral most extensively used in the arts i'^ 
Pyrolusite (black dioxide of manganese). Manganese ores are 
found in many localities. The very important iron alloy Spie- 
geleisen (ferro manganese), is obtained by the smelting of iron 
ore containing manganese. 
Manganese ores are employed in the arts for the liberation of 
chlorine, manufacture of bleaching powder, and in glazing and 
staining pottery. 
SPECIAL FEATURES. 
Large pieces in the center of the Hall: 
Object M. Gossan (iron ore), from Virginia. 
Object N. Limonite (oxide of iron), from Virginia. 
Object O. Mass of copper-nickel ore, from the Evans mine, 
Sudbury, Ontario, Canada, taken from the third level at a depth 
of 175 feet, and weighing about 12,000 pounds. Numerous large 
deposits of low grade nickel ore have recently been discovered in 
