How it began
Carl Auer von Welsbach, an Austrian chemist and engineer born in Vienna in 1858, studied at the University of Vienna and the University of Heidelberg and specialized in purifying rare-earth elements. In 1885, the same year he separated neodymium and praseodymium from a mixture called didymium, he patented an incandescent gas mantle that he called Auerlicht.
How it works
A fabric is impregnated with a mixture of metal salts and then burned. The fabric burns away and leaves a solid but fragile ash that glows brightly when heated by a gas flame. The National Inventors Hall of Fame describes the 1885 patent as using magnesium, lanthanum and yttrium oxides on guncotton, while Britannica describes the mantle as fabric impregnated with thorium nitrate and cerium nitrate.
What changed first
The mantle greatly increased the light that a gas lamp could give and brought light to the streets of Europe in the late 19th century. Edison's incandescent electric lamp was spreading quickly at the same time, and lamps fitted with Welsbach mantles gave efficient enough light that the gas industry was able to slow the advance of electric lighting.
What lasted
Work on the mantle led Welsbach to a metal filament made of osmium, which he then used in place of the carbon filament in electric lamps. His metal filament bulb lasted longer and used less electricity than carbon designs. Osmium was too rare for general use, but the improvement paved the way for the tungsten filament. He also developed misch metal and the flint used in lighters.
Where it stands today
Gas mantles were largely supplanted by the incandescent electric lamp. According to Britannica, the Welsbach mantle is still widely used in kerosene and other lanterns. Welsbach was inducted into the National Inventors Hall of Fame in 2011 for his incandescent device, covered by U.S. Patent No. 399,174.
