What is "gas mantle"

n. The incandescent gauze surrounding the flame in a gas lamp. It contains rare earths to enhance the light output.

An incandescent gas mantle, gas mantle or Welsbach mantle is a device for generating bright white light when heated by a flame. The name refers to its original heat source in gas lights which filled the streets of Europe and North America in the late nineteenth century, mantle referring to the way it is hung above the flame. Today it is still used in portable camping lanterns, pressure lanterns and some oil lamps.

Gas mantles are usually sold as fabric items which, because of impregnation with metal nitrates, form a rigid but fragile mesh of metal oxides when heated during initial use; these metal oxides produce light from the heat of the flame whenever used. Thorium dioxide was commonly a major component; being radioactive it has led to concerns about the safety of those involved in manufacturing mantles. Normal use, however, poses minimal health risk.