Carbide lamps became widely used by the 1920s. They were used for automobiles, lighthouses and even bicycles, but were most popular among miners because of the quality of light provided and because acetylene gas produced a fair amount of heat from a relatively small flame.
Carbide lamps, or acetylene gas lamps, are simple lamps that produce and burn acetylene (C2H2) (this colorless gas is widely used as a fuel), which is created by the reaction of calcium carbide (CaC2) (to generate acetylene gas) with water (H2O).
Acetylene gas lamps were used to illuminate buildings, as lighthouse beacons, and as headlights on motor-cars and bicycles. Portable acetylene gas lamps, worn on the hat or carried by hand, were widely used in mining in the early twentieth century. They are still employed by cavers (a person who explores caves).
This type of lamp generally has a reflector behind the flame to help project the light forward. An acetylene gas powered lamp produces a bright, broad light. The reaction of carbide with water is exothermic (a chemical reaction that releases energy) and produces a fair amount of heat independent of the flame.
Its use began shortly after 1900 and continued past 1950. Early models of the automobile, motorbike and bicycle used carbide lamps as headlamps. Acetylene gas also enabled early automobiles to drive safely at night. Picture on the top left is in the CSS Museum. The bottom right is an example of a lamp on a bicycle.