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No. 9.— Model of the Chandler iron mine, Ely, Minnesota. At 
the rear of the model two shafts descend, at levels 6 o feet apart, 
horizontal galleries run from the shaft and connect at intervals 
with other passages. P’igures of miners at work may be s^ieii by 
looking through these cross ways from the ends of the model. 
From the two main galleries sloping ways, not shown in the model, 
lead upward to passages at higher levels which do not connect, 
with the shaft. Here as the ore is excavated it is thrown through 
chutes to the tramways of the main galleries, and there taken by 
ore cars (see No. i6) to the shafts and raised to the surface. The 
timbering is to prevent the top and sides from caving. 
No. lO. — A model of a rail rolling-mill. 
Nos. 11 and 12. — Models of annealing furnace and rolling- 
mill for making structural iron, donated by Stumm & Co. 
No. 1,3. — Brick stoves, for heating the blast for the iron blast 
furnace. The three types are represented by models of the Whit- 
well, Siemens-Cowper and Gordon-Cowper-Whitwell stoves. 
No. 14r. — Electric rock drill. 
No. 15.— Rims for locomotive wheels; a solid steel shaft 
eight feet long, and twisted tram-car axles and bars. 
No. 16. — Ore car used in iron mines. (See No. 9.) 
No. 17.— Purvis ribbed steel furnace flues— as used in large 
boilers. A boiler front intended for use with such flues. 
No. 18. — Bars and twisted pieces of iron and steel from 
Avesta Steel Works, Sweden. 
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 (31,536,000) 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, con- 
taining: No. I — 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 Calamine (silicate of zinc): No. 6 — Silver ore: No. 
7— Iron ore (red hematite); No. 8-Iron Pyrite (sulphide of iron). 
