|In the earliest gas lighting the gas was lit directly from the open end of a pipe with no form of burner.|
The introduction of burners consisting of iron caps pierced with one or more holes improved the efficiency of gas lighting, but the caps corroded quickly and the luminosity varied greatly. These burners were known by the shape of the flame they made - rat-tail, cockspur, cockscomb and batswing.
Nevertheless, by 1823 there were 40,000 such street lamps lighting 213 streets in London. In 1858 William Sugg invented the steatite (soapstone) burner which would not corrode and let less heat escape from the flame.
Despite this and other developments, the second half of the 19th century saw lamps burning mineral oil and early electric lighting challenging gas lighting until the invention of the gas mantle.
Gas mantles appeared on the scene in 1887 after Carl Auer, a chemist at Bunsen's laboratory in Heidleburg, discovered by accident that asbestos soaked in "rare earth" compounds gave an intense glow when heated by a gas flame.
The early gas mantles were not very efficient and were extremely fragile. They cost about 5/- (25p) each and the whole burner had to be sent back to the manufacturer if a new mantle was needed. The quality of gas mantles improved over the years however and they were used in street lighting in London for the first time in 1895.
As electric lights improved gas lighting declined and by 1933 half the streets of London were lit by electricity. The last of Birmingham's gas lights were removed in 1975 and with one or two notable exceptions such as the frontage of Buckingham Palace, gas lights are only used in caravans, boats and building sites with a bottled gas supply.