The name is absent

274 Science and Human Welfare

sistance to heat and corrosion. It makes steel strong, yet
ductile and shock-resistant. Chromium is the key that has
opened, and is still opening, great new fields of application
for steel. Without chromium the whole wonderful series of
stainless steels would not have been possible. From tarnish-
free tableware to corrosion-resistant chemical equipment;
from strong, light-weight truck bodies to streamlined trains
and airplanes; from heat-defiant boiler tubes to high-tem-
perature steam turbines, chromium has made possible a steel
with desired properties of the noble metals. But the stainless
steels are only one great contribution of chromium. This
element has also helped to provide long-wearing engine
valves, strong, tough gears, tools, ball-bearings, shafts,
springs, and hundreds of other improved articles. When
engineers, about fifty years ago, produced chrome-steel pro-
jectiles that easily pierced the best armor plate of the day,
all the warships became obsolete overnight. The answer was,
of course, armor plate of chrome-nickel steel. Some years ago
we were practically dependent upon outside sources for
chromium. At that time our relatively low-grade ores made
it impossible for domestic producers to compete with foreign
suppliers who had the advantage of richer deposits. Now
concentration methods have been devised which make this
ore available.

What nickel has to contribute to the industrial field is not
only corrosion resistance but also physical and mechanical
properties which give the metal, particularly in alloy form,
definite structural importance. To a considerable extent the
participation of nickel is through nichrome alloys and monel-
metal, the 32-68 nickel-copper alloy which now is produced
with the strength of steel.

Tungsten is another strategic metal. Since sheelite glows
with a fluorescent light in the rays of an ultraviolet lamp,

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