Neon is a colorless, odorless, inert gas, first discovered in 1898 by the British physical chemists Sir William Ramsay and Morris W. Travers, who named the gas after the Greek word meaning “new.”
About that time physicists were experimenting with generating radiation by striking an arc between electrodes in an evacuated tube containing only small amounts of vapor.
In Paris in 1910, Georges Claude filled a tube with neon gas and found that when high voltage was applied to the two electrodes at each end, an electrical discharge occurred, which caused the tube to glow a deep red.
The neon must be purified of any other gases in order for the electrical discharge to permeate it and pass through the tube. Purification is accomplished by the use of charcoal which, when cooled to – 180 to – 190 degrees Centigrade, absorbs impurities in the tube and is subsequently removed.
The commercial applications for neon lighting were quickly recognized in the early twentieth century, and soon other vapors besides neon were used. Mercury vapor, for example, gives rise to blue light.
White fluorescent lights, developed in the 1930’s, actually are filled with mercury vapor, but the inner wall of the tube is coated with material that fluoresces white under radiation.