66 
ite, gibbsite and cryolite — are shown in the case, together with 
pigs and sheets of the metal and specimens of its alloys. 
IRON. 
Case K. — Iron ores from the ranges of the Lake Superior 
region. It is the near presence of the remarkably pure and abun- 
dant deposits of hematite and magnetite^hsX has enabled Chicago’s 
iron industry to attain its present importance. 
Case L. — Type specimens of iron ores. These are: — the 
black oxide, magnetite, 72 per cent, iron ; the red oxide, hematite, 
70 per cent, iron; the hydrous oxides, turgite, 66 per cent, iron; 
gdthite, 64 per cent, iron; and limonite ; (io cent, iron; the car- 
bonate, siderite, 48 per cent. iron. Many varieties of these ores 
are shown, which are known by the names of yellow ochre, hog 
ore, pipe ore and brown hematite, forms of limonite ; red ochre, 
specular, micaceous, needle and kidney ores, forms of hematite; 
clay iron stone, black band, and spathic ores, forms of siderite. 
The rest of this case is occupied by ores from the Western states. 
Case 16. — A series of limonites from the Eastern states that 
illustrate the transition from a porous, impure bog-iron ore, to a 
compact brown limonite and through gbthite and turgite to hem- 
atite. 
Case 17, Front. — Iron ores. Western States. 
Case 17, Rear. — Iron ores, New South Wales. 
Case J. — Iron ores, England, France, Germany and Russia. 
Conspicuous among the English ores are the ochres, which are 
mixtures of limonite or hematite with clay; the soft, bright red 
hematites which occur in limestone, and the compact spathic ore 
of the coal measures. The German irons show the more fibrous 
hematites and limonites and the well crystallized “sparry” sider- 
ite. 
Case H. — Iron ores. South and Central America together 
with a series of ores and associated rocks from the Cerro Mer- 
cado or Iron Mountain of Mexico. 
MANGANESE. 
Cases 18 and 19. — Ores of manganese, Colorado, Virginia, 
Arkansas, Brazil and Great Britain; chiefly the black oxides. 
