of
very fine particles of metallic platinum throughout the mass. Some "
contact mass " contains as much as 7 to 8 per cent by weight of
platinum, and other manufacturers make a mass containing as little as
0.2 per cent metallic platinum by weight.
It
is impossible at this time to state the quantity of platinum used in
the sulphuric-acid industry in this country, but it is believed that
the loss of platinum in well-regulated practice is very small. The
platinum does not enter into the chemical reactions, but rather acts as
an exciter in the formation of sulphur trioxide, which, on combination
with water, yields sulphuric acid.
Platinum
dishes and utensils of many kinds are still a necessity in chemical
laboratories and many chemical industries, but the use of this metal in
the electrical industry is each year becoming less. In the manufacture
of incandescent lamps a large quantity of platinum was formerly used,
but at present wires made of nickel-chromium alloys or metallic
tungsten or metallic molybdenum are used. The resistance wires of
electric furnaces and heaters at one time contained considerable
platinum, but metallic molybdenum has now to a considerable extent
replaced the more expensive metal. Formerly the electrical ignition
points of gas engines were made of platinum, but it is believed that
most of the spark-plug points now used are made of metallic tungsten.
The
dental industry once used a large quantity of platinum in making
artificial teeth. It is understood that recently metallic molybdenum
plated with platinum is widely used rather than pure platinum.
The
art of platinum plating has now been perfected to so remarkable a
degree that jewelers are no longer under the necessity of using so much
platinum as formerly in making jewelry, though platinum is still
considered the best setting for precious gems. This use of platinum,
however, is somewhat subject to the reigning fashion. Of interest in
this connection is a bill which was prepared by the National Jewelers'
Board of Trade of New York early in 1914 for presentation to the New
York Legislature, making it a misdemeanor to mark inferior jewelry "
platinum," " pure platinum," or " solid platinum " unless it is 0.950
fine or contains 95 per cent platinum group metals.
A somewhat similar law was passed by the Swiss Federal Council, to be effective March 1, 1914.1
This law provides that "upon request of the manufacturer, seller, or
purchaser, articles having a minimum platinum content of 95 per cent
will receive the official stamp of an Alpine goat."
NOTES ON THE PLATINUM INDUSTRY.
UNITED STATES. CALIFORNIA.
The
greater part of the platinum recovered in California in 1914 was
obtained as a by-product from the dredges at Oroville and Folsom. It is
possible that the recovery of platinum by these dredges may be somewhat
increased in the near future by the use of jig sluices, such as that
installed on the Yosemite Dredging & Min-
1 Commerce Reports, No. 914, Mar. 25, 1914, p. 1128.
