A Blaze of Crimson Light: The Story of Neon
Detail of Corning Glass Works advertisement, 1937. (Courtesy Jane E. Boyd)
I smelled Los Angeles before I got to it. It smelled stale and old like a living room that had been closed too long. But the colored lights fooled you. The lights were wonderful. There ought to be a monument to the man who invented neon lights. Fifteen stories high, solid marble. There’s a boy who really made something out of nothing.
—Raymond Chandler, The Little Sister, 1949
Philip Marlowe, the hard-boiled hero of Raymond Chandler’s detective novels, was right about neon. The inventors of the lights that set the night sky aglow in a thousand cities literally had made something out of nothing. The colorful words and pictures came from the air itself—mysterious gases extracted from the atmosphere, trapped in glass tubes, and zapped with electric current to create luminous reactions. During the 20th century, lights fueled by neon and its fellow noble gases were icons of commerce and entertainment, illuminating the modern age. Some early computers and calculators even used small neon tubes for circuits and displays. Today, many of the large, elaborate neon signs have sputtered out, replaced by newer or cheaper technologies, but these gas-filled tubes still shine on a smaller scale, treasured for their unique light.
Aristocrats of the Air
The story of neon begins in the 1890s, with Scottish chemist Sir William Ramsay. Best known as the codiscoverer of four of the noble gases (neon, argon, krypton, and xenon), Ramsay also isolated and characterized helium and radon, the other two noble gases, winning the Nobel Prize for his efforts. Together, these six gases form a family of elements distinguished by their unwillingness to bond with other atoms. This standoffish “nobility” gave the noble gases their name.
It was a long time before the atmosphere gave up all its secrets. As early as 1785 prominent chemist Henry Cavendish had noted a small residue of gas left over after he removed oxygen (then known as “dephlogisticated air”) and what we know now as nitrogen from “common air.” Ramsay and his mentor John William Strutt, 3rd Baron Rayleigh, took up the challenge of identifying this mystery gas. In 1894 they began attacking air with brute-force methods—combustion, reaction, and absorption—to strip away every possible atom of nitrogen and oxygen. In one early experiment they removed oxygen from air using red-hot copper. To remove nitrogen the deoxygenated air was passed over red-hot magnesium, soda lime, copper oxide, and phosphoric anhydride. After further steps eliminated the remaining nitrogen and oxygen, they named the residual gas argon (derived from the Greek for “the inactive or lazy one”).
Though argon makes up less than 1% of the atmosphere, Ramsay suspected that there were even rarer gases hidden in the air. In the summer of 1898 he and his colleague Morris W. Travers hunted down these additional elements. Starting with purified argon liquefied at low temperatures, they slowly added heat to isolate gases that boiled at temperatures both above and below argon’s boiling point. In this way they discovered neon, krypton, and xenon (Greek for “the new one,” “the hidden one,” and “the stranger”).
Though these rare gases are invisible to the naked eye, each one glows with a distinctive brilliant color when sealed in a glass tube and energized with high voltage. These gas-discharge tubes, named for the electrical discharge that made them light up, would become the basis for neon lamps. Ramsay found neon’s light particularly striking. In his 1904 Nobel Prize lecture he described the neon spectrum as “a brilliant flame-coloured light, consisting of many red, orange, and yellow lines.” Travers was even more effusive:
The blaze of crimson light from the tube told its own story, and it was a sight to dwell upon and never to forget. It was worth the struggle of the previous two years; and all the difficulties yet to be overcome before the research was finished . . . for nothing in the world gave a glow such as we had seen.
Mining the Air
Beginning in the late 19th century liquid air, particularly oxygen, found many uses, including in theater lighting and industrial welding. All techniques for liquefying gases used the Joule-Thomson effect—seen in the home or office today whenever a can of pressurized air is used to dust a computer keyboard (as the air expands through the nozzle, the temperature drops and condensation forms on the can). The first practical methods to liquefy air on a large scale appeared while Ramsay was working to isolate his gases, and he made sure to thank William Hampson, one of the men responsible, in his Nobel Prize lecture.