Carl Auer von Welsbach (1858-1929), Austrian chemist and inventor. In 1885, he discovered the rare earth elements neodymium and praseodymium, isolating them from a mixture (didymium) which was formerly thought to be an element. Continuing his research on rare earth metals, he developed the gas mantle lamp. This produced a bright light by using fabric impregnated with thorium and cerium nitrates burning in a gas flame. He was the first to use a metallic filament in incandescent lamps. As well as this, he developed misch metal, an alloy of rare earth metals. He alloyed this with iron to produce Auer's metal, which is used in the insflintsins in cigarette lighters.