77 
and Gold Mine, New South Wales. 36 tons yielded 3,406 oz. silver, 
and gold at the rate of 15 dwt. per ton. 
XJ. — Auriferous Pyrite, Park County, Colo. Assays $45 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. 
HALLS 73, 74 AND 76. 
Hall 73. — Office of the Department of Geology. 
Hall 74. — Library of the Department of Geology. The works 
in this library treat of geology and kindred subjects, and are in- 
tended primarily for the use of officers of the Department. On 
application to the curator, however, opportunity will be given to 
visitors to consult any special work. The collection of photographs 
and autographs of leading geologists and mineralogists of the 
the world, made by Mr. Geo. F. Kunz, is exhibited here. 
Hall 73. — Laboratory of the Department of Geology. Here 
are shown apparatus and chemicals used in determining minerals 
and ores and illustrations of tests for the different metals. Assay 
furnaces and other laboratory appliances are also exhibited. On 
the walls are over fifty sketches enlarged from wood cuts in De 
Re Metallica, showing methods of mining and the metal working 
appliance used in the sixteenth century. Twenty-five photographs 
of the works at Playa Blanca, Chile, show furnaces and apparatus 
used in the treatment of ores of that locality. 
