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modern company, collecting these slags and using them as otes, 
extracts sufficient lead and silver to yield a good profit. 
Case 1 . — Treatment of the copper-bearing lead ores of the 
Unterharz, Germany. A collection of specimens illustrating all 
steps in the process of extracting lead, copper, silver and gold 
from these ores. 
Case «J. — Uses of lead. Alloys of lead with other metals, 
sheet lead, shot, red lead, white lead. Parke’s process of de-sil- 
verizing base bullion. 
The visitor should now pass to the eastern end of the hall and 
note the following special groups in the center. 
K. — Silver, lead and copper ore, Cordillera Hill silver mine, 
Peelwood, New South Wales. 
L. — Gold and silver ore, British Columbia. 
M. — Gold and silver ore from the State of Washington and 
other American localities. 
N. — Zinc-lead ore, Laurium, Greece. 
O. — Copper-silver ore, Leadville, Colorado. Assays gold, $6 
per ton; silver, 41 oz. per ton; copper, 18 per cent. 
P. — Silver-lead ores, Barrier Range, New South Wales. 
Assays silver, 58 oz. per ton; lead, 72 per cent. 
Q. — Gold-copper silver ore, Ouray County, Colorado. Assays 
copper, 28 per cent.; silver, 160 oz.per ton. 
R. — Auriferous quartz, San Miguel County, Colorado. Assays 
average $6 to $8 gold per ton. 
S. — Silver and gold ore from the State of Washington, and 
other specimens from American localities. 
T. — Block of ore from 40 foot level of the Back Creek Silver 
and Gold Mine, New South Wales, 36 tons yielded 3,406 oz. silver, 
and gold at the rate of 15 dwt. per ton. 
U. — Auriferous Pyrite, Park County, Colo. Assays $25 worth 
of gold per ton. 
Around the walls of the room will be found, arranged in order, 
large blocks of gold, silver and lead ores, giving an excellent 
opportunity to study the characteristic appearances of such ores 
and the minerals most commonly associated together in them. 
The latter are quartz, fluorite and barite, copper and iron pyrites 
and galena. The rusty looking ores are simply more or less de- 
composed forms of the above. 
