From 1888 to 1940, the Welsbach Gas Light Company held exclusive manufacturing and sales rights to the Welsbach gas mantle, a device made of fibers impregnated with oxides of thorium and cerium that produced bright white light when heated with a gas flame. Invented in 1880's by Austrian scientist Carl Auer Von Welsbach (1858-1929), these gas mantles were used extensively in street lighting and in gas-powered appliances. The Welsbach gas mantle also was the first industrial product to make use of rare earth elements. At peak production, the Welsbach factory employed 2,000 people, including a large number of women skilled at the sewing and other precision handwork involved in the manufacturing process.
