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eight feet long, and twisted tram-car axles and bars. 
No. 14.— Model of a rolling mill for rolling structural iron 
and steel. This mill rolls the largest beams of any in Germany. 
No. 15.— Purvis ribbed-steel furnace flues— as used in ma- 
rine boilers. A boiler front intended for use with such flues. 
These flues were forged by hydraulic power and are a good 
example of the large objects which iron workers can readily 
No. 16. — Model of machinery and annealing furnaces used 
in preparing molds for cast iron pipe. 
No. 17. — Model of a rolling mill. The three models, Nos. 
14, 16 and 17 show portions of the ironworks of Gebruder Stumm, 
Germany. . 
No. 18. — “Specimens of rolled wrought-iron and steel 
worked cold.” These are from the factory of Stumm & Co. 
Upon the walls there is a series of charts illustrating the 
kinds of furnaces used in the manufacture of iron. 
HALL 80. 
WEST DOME. 
Beneath the center of the dome stands a statistical column, 
giving the bulk of each product of the mines of the United States 
in 1892, for one second of time. Multiplying this by the number 
of seconds in the year (3,536,000) will give the annual product. 
This column was built according to data given by the United 
States Geological Survey. In the four niches are pyramids of ore, 
containg: No. 1— Gold and Silver Ores: No. 2— Tin Ore: No. 3— 
Iron Ore: No. 4— Copper Ores. 
The four large specimens surrounding the column are respect- 
ively: No. 5 — Smithsonite (carbonate of zinc): No. 6— Silver Ore: 
No. 7— Iron ore (red hematite): No. 8— Iron Pyrite (sulphide of 
iron). 
