WelsbachWels"bach\, a. Of or pertaining to Auer von Welsbach or the incandescent gas burner invented by him. Welsbach burner, a burner in which the combustion of a mixture of air and gas or vapor is employed to heat to incandescence a mantle composed of thoria and ceria. The mantle is made by soaking a "stocking" in a solution of nitrates of thorium and cerium (approx. 99 : 1), drying, and, for use, igniting to burn the thread and convert the nitrates into oxides, which remain as a fragile ash. The light far exceeds that obtained from the same amount of gas with the ordinary fishtail burner, but has a slight greenish hue.