Gas lighting is the production of artificial light from combustion of a gaseous fuel, such as hydrogen, methane, carbon monoxide, propane, butane, acetylene, ethylene, coal gas (town gas) or natural gas. The light is produced either directly by the flame, generally by using special mixes (typically propane or butane) of illuminating gas to increase brightness, or indirectly with other components such as the gas mantle or the limelight, with the gas primarily functioning as a heat source for the incandescence of the gas mantle or lime. Before electricity became sufficiently widespread and economical to allow for general public use, gas was the most prevalent method of outdoor and indoor lighting in cities and suburbs, areas where the infrastructure for distribution of the gaseous fuel was practical. When gas lighting was prevalent, the most common fuels for gas lighting were wood gas, coal gas and, in limited cases, water gas. Early gas lights were ignited manually by lamplighters, although many later designs are self-igniting. Gas lighting now is frequently used for camping, for which the high energy density of the hydrocarbon fuel, combined with the modular nature of canisters on which camping lights are built, allows for bright and long lasting light to be produced without complex equipment. In addition, some urban historical districts retain gas street lighting, and gas lighting is used indoors or outdoors to create or preserve a nostalgic effect. Background Prior to use of gaseous fuels for lighting, the early lighting fuels consisted of olive oil, beeswax, fish oil, whale oil, sesame oil, nut oil, or other similar substances, which were all liquid fuels. These were the most commonly used fuels until the late 18th century. Whale oil was especially widely used for lighting in European cities such as London through the early 19th century. Chinese records dating back 1,700 years indicate the use of natural gas in homes for lighting and heating. The natural gas was transported by means of bamboo pipes to homes. The ancient Chinese of the Spring and Autumn period made the first practical use of natural gas for lighting purposes around 500 B.C. in which they used bamboo pipelines to transport both brine and natural gas for many miles, such as the ones in Zigong salt mines. Public illumination preceded by centuries the development and widespread adoption of gas lighting. In 1417, Sir Henry Barton, Lord Mayor of London, ordained "Lanthornes with