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 tungsten powder and thorium oxide through a perforated diamond of the desired diameter.  The filament so produced is drawn through a chamber heated to 2500 deg.  C. at a velocity of eight feet an hour, which crystallizes the tungsten into a continuous thread.

The first metallic filament used in the electric light on a commercial scale was made of tantalum, the metal of Tantalus.  In the period 1905-1911 over 100,000,000 tantalus lamps were sold, but tungsten displaced them as soon as that metal could be drawn into wire.

A recent rival of tungsten both as a filament for lamps and hardener for steel is molybdenum.  One pound of this metal will impart more resiliency to steel than three or four pounds of tungsten.  The molybdenum steel, because it does not easily crack, is said to be serviceable for armor-piercing shells, gun linings, air-plane struts, automobile axles and propeller shafts.  In combination with its rival as a tungsten-molybdenum alloy it is capable of taking the place of the intolerably expensive platinum, for it resists corrosion when used for spark plugs and tooth plugs.  European steel men have taken to molybdenum more than Americans.  The salts of this metal can be used in dyeing and photography.

Calcium, magnesium and aluminum, common enough in their compounds, have only come into use as metals since the invention of the electric furnace.  Now the photographer uses magnesium powder for his flashlight when he wants to take a picture of his friends inside the house, and the aviator uses it when he wants to take a picture of his enemies on the open field.  The flares prepared by our Government for the war consist of a sheet iron cylinder, four feet long and six inches thick, containing a stick of magnesium attached to a tightly rolled silk parachute twenty feet in diameter when expanded.  The whole weighed 32 pounds.  On being dropped from the plane by pressing a button, the rush of air set spinning a pinwheel at the bottom which ignited the magnesium stick and detonated a charge of black powder sufficient to throw off the case and release the parachute.  The burning flare gave off a light of 320,000 candle power lasting for ten minutes as the parachute slowly descended.  This illuminated the ground on the darkest night sufficiently for the airman to aim his bombs or to take photographs.