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Case 21, — High test illuminating oils. 
Case 22, — Illustrations of some of the varied uses to which 
petroleum products can be put. These include waxed paper for 
wrapping purposes, water proof coating for explosives, varnishes, 
wood stains and fillers, rubber cements, electric light carbons, etc. 
Series showing Russian petroleum- and its products. 
HALL 72. 
PLATINUn, GOLD, SILVER AND LEAD. 
The collections in this Hall comprise the typical platinum, 
gold, silver and lead ores. In the examination of these, as well as 
ores of other metals, it should be remembered that the mineral or 
metal is frequently present in such minute quantities that it can- 
not be seen by the naked eye or even with the aid of an ordinary 
magnifying glass. The ores usually possess, however, character- 
istics of appearance or of associations with other minerals, known 
as gangue minerals, which enable a skillful observer to recognize 
them as being metalliferous. 
There are also to be seen here products resulting from the 
metallurgical treatm.ent of the ores. 
PLATINUM. 
Case A. — Specimens illustrating modes of occurrence of plat- 
inum in nature, from over twenty different localities, including 
Washington, Oregon and California, the United States of Colom- 
bia and the Ural Mountains. In all of these specimens the metal 
may be seen in the form of flattened grains often associated with 
iridium, osmium, palladium, gold, copper and chromite. The 
grains are usually found in river beds or placer deposits. A com- 
plete series of rocks and soils bearing platinum, from the Demi- 
doff Platinum Mines, Nizhni Tagilisk, Ural Mountains is shown, 
as well as a series of concentrates produced by washing these in 
order to separate the metal. Some other uses of platinum are 
illustrated as follows : Russian platinum coin for a time used as 
money ; coins struck in platinum and gilded which passed for gold 
