\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.