a gas burner with a gauze mantle impregnated with thorium oxide and cerium oxide: when lighted, the gauze gives off an incandescent, greenish light
See Welsbach burner in American Heritage Dictionary 4
(wĕlzˈbăkˌ, -bäkˌ)
A trademark used for a lamp consisting of a gas burner and a gauze mantle impregnated with cerium and thorium compounds that becomes incandescent when heated by the burner.