Science: Neon Tubes Improved

When people see an advertising sign in which the letters or designs are formed by slender glowing glass tubes, they may know at once that it is a neon light sign. Although effective as displays, these lights are expensive because of the high voltages necessary to start them glowing. Last week Raymond R. Machlett, 30, Manhattan electrical engineer who, when he was 26, was one of the first to develop a commercially satisfactory Neon tube, announced that by altering the construction slightly, he had been able to light a neon lamp with a 220-volt current, the ordinary household voltage. Present tubes require a 10,000-volt current, expensively stepped-up from service current by transformers.

If Inventor Machlett’s improvement is a success, it may be possible to use neon lamps in homes and offices to replace incandescent bulbs. The brightness of the incandescent filament is usually too intense, requires lamp shades. Neon light is diffused, needs no shading. It more nearly approaches daylight, gives off healthful ultra violet rays.

Though “neon tube” is the term commonly applied to all kinds of lighting tubes containing luminous gases, not all such tubes contain the gas neon. The majority of signs first made four years ago used only neon gas, which gives a red light,

But scientists had already learned that by using other gases they could get other colors—argon & mercury vapor for blue, the same combination in a yellow tube for green, carbon dioxide for white. The gases are confined in the tubes at low pressures (5 to 10 millimetres, compared to 760 millimetres in the sea-level atmosphere). The gases are made to glow by an alternating electric current flowing through them. Because of the penetrating quality of the infra-red rays given off, neon lamps are used as fog beacons, airfield lights.