Today in Technology History
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September 17
One century ago, on September 17, 1901, Peter Cooper Hewitt received a patent for his vapor lamp -- an important forerunner of today's fluorescent lights.
Hewitt (1861-1921) was the grandson of the famous Peter Cooper, a great American engineer and industrial pioneer. Hewitt inherited his ancestor's inventive mind. One biographer thus described Hewitt: "Those who knew him, watching him work, felt that a part, at least, of Hewitt's thinking apparatus was in his hands."
Edison's famous incandescent bulb was already several years old when Hewitt began working on electrical lighting. Instead of using a filament as Edison had, Hewitt exploited a quirk of chemistry: when certain gases are exposed to electricity, they ionize and make light.
Hewitt carefully fashioned a glass lamp chamber and removed all the air from inside, producing a vacuum. Then he introduced a gas -- usually mercury vapor. He then fed an electrical current to the two electrodes in his lamp, resulting in an arc of bright light.
The good news was that his lamp was much more efficient than incandescent bulbs -- needing just an eighth of the electricity. The bad news was that it produced only an unnatural blue-green light. Nevertheless, the mercury vapor lamp was very useful for photographers and motion picture producers who didn't care about the color of the light -- after all, they only had black and white film. Hewitt's lamps also had certain commercial applications. Generations of refinements in arc lighting have resulted in the fluorescent bulbs common today.
Related links:
Click here to read about Hewitt and his lamp.
Click here to see a picture of Hewitt's gravestone.
Click here to read about the history of high-intensity discharge lamps.
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