Source : Webster's Revised Unabridged Dictionary (1913)

Welsbach \Wels"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.