HALL 76. 
METALLURGY OF IRON AND STEEL, 
This hall contains a series of the intermediate and final prod- 
ucts 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-workers art. 
No. 1 .— Electric rock drill, for use in mines where steam drills 
are inconvenient or costly. 
No. 2.— Model of the Chandler iron mine, Ely, Minnesota. 
At the rear of the model two shafts descend at levels 6 o feet 
apart, and horizontal galleries run from the shaft and connect at 
intervals with other passages. Figures of miners at work may be 
seen 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. 3) to the shafts and raised to the sur- 
face. The timbering is to prevent the top and sides from caving. 
No. 3.— Ore car used in iron mines. (See No. 2.) 
Cases No. 4 A and 6A.— A collection illustrating the 
methods of testing structural iron and steel. In general a piece 
of steel is broken and the strain at which it yields is noted. Other 
pieces are bent hot and cold and their behavior in respect to 
cracking is noted. At the ends of the cases are specimens show- 
ing the successive stages of rolling an ingot into a rail or beam, 
also the method of crushing a number of bars or “ pile ” of iron 
into one solid beam. 
Case 4 B.— The extraction of iron from its ores by the blast 
furnace. The material fed to the furnace and given out by it is 
shown, also a series of pig irons showing the characteristic frac- 
tures of the different grades. 
Cases 4 C and D.— Alloys of iron used in iron working. 
5. — Model of a Gordon-Whitwell-Cowper hot blast 
stove used for heating the air for the blast furnace. 
Case 6 B.— Direct process wrought iron. The example 
