s. All the ore was
shipped to Germany and the British Admiralty was content to buy from the
Germans what tungsten was needed for armor plate and heavy guns. When
the war broke out the British had the ore supply, but were unable at
first to work it because they were not familiar with the processes.
Germany, being short of tungsten, had to sneak over a little from
Baltimore in the submarine _Deutschland_. In the United States before
the war tungsten ore was selling at $6.50 a unit, but by the beginning
of 1916 it had jumped to $85 a unit. A unit is 1 per cent. of tungsten
trioxide to the ton, that is, twenty pounds. Boulder County, Colorado,
and San Bernardino, California, then had mining booms, reminding one of
older times. Between May and December, 1918, there was manufactured in
the United States more than 45,500,000 pounds of tungsten steel
containing some 8,000,000 pounds of tungsten.

If tungsten ores were more abundant and the metal more easily
manipulated, it would displace steel for many purposes. It is harder
than steel or even quartz. It never rusts and is insoluble in acids. Its
expansion by heat is one-third that of iron. It is more than twice as
heavy as iron and its melting point is twice as high. Its electrical
resistance is half that of iron and its tensile strength is a third
greater than the strongest steel. It can be worked into wire .0002 of an
inch in diameter, almost too thin to be seen, but as strong as copper
wire ten times the size.

The tungsten wires in the electric lamps are about .03 of an inch in
diameter, and they give three times the light for the same consumption
of electricity as the old carbon filament. The American manufacturers of
the tungsten bulb have very appropriately named their lamp "Mazda" after
the light god of the Zoroastrians. To get the tungsten into wire form
was a problem that long baffled the inventors of the world, for it was
too refractory to be melted in mass and too brittle to be drawn. Dr.
W.D. Coolidge succeeded in accomplishing the feat in 1912 by reducing
the tungstic acid by hydrogen and molding the metallic powder into a bar
by pressure. This is raised to a white heat in the electric furnace,
taken out and rolled down, and the process repeated some fifty times,
until the wire is small enough so it can be drawn at a red heat through
diamond dies of successively smaller apertures.

The German method of making the lamp filaments is to squirt a mixture of
tungst