67 
pyrolusite and psilomelane. By far the most important use of 
manganese is in the manufacture of steel. It is also used in 
large quantities for the liberation of chlorine for bleaching, for 
staining glass and pottery, and in the extraction of gold from its 
ores. 
Case 20. — Alloys illustrating uses of iron and manganese. 
CENTER OF THE HALL, 
M. — Gossan (iron ore), from Virginia. 
N. — Limonite (oxide of iron), from Virginia. 
O. — Mass of copper-nickel ore, from the Stobie mine, Sud- 
bury, Ontario, Canada, taken from the third level at a depth of 
175 feet, and weighing about 12,000 pounds. 
P. — Limonite (brown oxide of iron), from Russia. 
Q. — Zinc-lead ore, France. 
R. — Statue of Vulcan, the Roman god of fire and metal 
working, of hammered copper on a pedestal of iron beams, from 
the exhibit of Gebriider Stumm at the World’s Columbian Ex- 
position. It typifies strength and skill in utilizing the products of 
the mineral kingdom. 
S. — Hematite (red oxide of iron), Wyoming. 
T. — Copper ore (bornite). Cape Colony, South Africa. 
U. — Large mass of Smithsonite (zinc carbonate), Arkansas. 
The weight of this mass is about 10,000 pounds. 
Wall Cases V and W. — Large specimens of the ores shown 
in this hall which give some idea of how such ores look in bulk. 
The visitor should now return to the dome and turning to the 
left pass into hall 76. 
HALL 76. 
METALLURGY OF IRON AND STEEL. 
This hall contains a series of the intermediate and final pro- 
ducts of the iron-working industry, intended to lead the visitor 
gradually from a view of the mining of the ore to some of the 
higher products of the iron- worker’s art. 
No. 1, — Model of the Chandler iron mine, Ely, Minnesota. 
At the rear of the model two shafts descend and at levels 60 feet 
