62 
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. — Gold ore. A group of large specimens of refractory gold 
ores. 
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. sil- 
ver, and gold at the rate of 1 5 dwt. per ton. 
U. — Gold ore, Alma, Park Co., Colorado. Assays $25 per ton. 
Wall Case V. — Large specimens or silver and lead ores. 
Around the walls of the room will be found, arranged in order, 
large blocks of gold, silver and lead ores, giving an excellent op- 
portunity 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 decom- 
posed forms of the above. 
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 (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, 
containing: No. i — Gold and Silver Ores; No. 2 — Tin Ores; 
No. 3 — Iron Ores; No. 4 — Copper Ores. 
The four large specimens surrounding the column are respect- 
ively: No. 5 — Zinc Ore; No. 6 — Silver Ore; No. 7 — Iron Ore; 
No. 8 — Nickel Ore. 
HALL 79. 
COPPER, ZINC, TIN, ANTIMONY, MERCURY, NICKEL, 
IRON, MANGANESE AND THE 
MINOR METALS. 
The collections in this hall comprise the typical copper, zinc, 
tin, antimony, mercury, nickel, iron, and manganese ores, and the 
ores of various metals of minor importance. There are also to be 
