THE FATHER OF THE NEON LIGHTBULB: DANIEL McFARLAN MOORE

DANIEL MCFARLAN MOORE is little remembered today. However, he invented one of the first commercially available discharge lamps as well as a small glow lamp that can still be found in almost every American home.
   Moore began his lighting career working for Thomas Edison, but turned to experimenting with the idea of obtaining light from electrical discharges. While not a new idea -- Henrich Geissler made light emitting tubes in the 1850s -- Moore felt that glass sealing techniques had advanced enough since then to allow a commercial product. Edison was not keen on the idea of something which might compete with his incandescent lamp, and reputedly asked Moore, "What's wrong with my lamp?" Moore's quick response of " It's too small, too hot, and too red" should leave little wonder why Moore soon started into business for himself.
By 1898 Moore had devised his "Moore Lamp." The lamp consisted of gas-filled glass tubes about 2 inches in diameter joined together in lengths up to 250 feet. Once installed, air was removed from the tube and a small amount of gas, usually nitrogen or carbon dioxide, inserted. An electric current passed between electrodes mounted in either end of the lamp, just as in later neon tubes inspired by Moore's work. Current and gas pressure were regulated by devices installed in a box from which both ends of the tube emerged.
   The Moore lamp proved difficult to install, requiring the services of a "glass plumber" who custom fit 10 foot lengths of tubing to a customer's space. The tubes also leaked. But carbon dioxide gave a good quality white light at an efficacy of about 10 lumens per watt -- almost triple the efficacy of Edison's lamp. Moore lamps sold modestly well for commercial installations, until 1910 when William Coolidge's tungsten filament lamp also achieved 10 lpw. Moore's company failed and he went to work for General Electric.
   Moore's lasting legacy was his 1920 invention of the glow lamp. These small, low power devices use a physical principle called "coronal discharge." Moore mounted two electrodes close together in a bulb and added neon or argon gas. The electrodes would glow brightly in red or blue, depending on the gas, and the lamps lasted for years. Since the electrodes could take almost any shape imaginable, a popular application has been fanciful decorative lamps. Glow lamps found practical use as indicators in instrument panels and in many home appliances until the acceptance of Light-Emitting Diodes (LEDs) in the 1970s. The next time you see a coffee urn with an orange, glowing light above the spigot, think of D. McFarlan Moore. 
   In 1924 he invented the vacuum bulbs used in telephotography, and in 1925 improved it for use in television. Moore was awarded the John Scott Medal of the Franklin Institute in 1911.
   A protege of fellow scientist and inventor Nicola Tesla, Moore is reported to have worked closely with Tesla on many experiments dealing with light refraction and harmonics, though records of the results of these experiments have been lost to time.
   On June 15, 1936, at the age of 67, Moore was thrust into the realm of obscurity when he was shot to death on the lawn of his home in East Orange, New Jersey by an unemployed inventor who became enraged after finding that an invention he filed for, was already the subject of a patent granted to Moore.

Shown above is a letter from my personal collection typed on Edison Light Works stationery signed by D. McFarlan Moore. This letter concerns a board meeting of the I.E.S. (Illuminating Engineering Society). It is addressed to W.T. Blackwell of the New Jersey Public Service Gas Co. and is dated May 24, 1923.