Non-ductile Tungsten Lamp
date: label: Date made
content: ca 1908
label: date made
content: ca. 1908
name: label: maker
content: General Electric
notes: label: Description
content: Thomas Edison and others considered element number 6, carbon, ideal for lamp filaments in part because it has the highest melting point of any element. Element number 74, tungsten, has the next highest melting point but it then existed only as a powder. Attempts to make it into a workable form failed until early in the 1900s when a burst of invention occurred in Europe. A pressing technique called "sintering" (squeezing a material into a dense mass) was adopted by several inventors.
label: Description
content: The most commercially successful design proved to be that of Dr. Alexander Just and Franz Hanaman of Austria. Their work on sintering tungsten was based on a prior sintering process developed by Carl Auer von Welsbach for his filament made of osmium. Just and Hanaman made a tungsten and organic paste, squirted it through a die, baked out the organic material, then sintered the tungsten in a mix of gasses. The resulting filament gave about 8 lumens per watt and lasted 800 hours.
label: Description
content: Another Austrian, Dr. Hans Kutzel, used an electric arc to make a tungsten and water paste. He then pressed, baked, and sintered the tungsten in a manner similar to Just and Hanaman's procedure. Yet another pair of Austrians, Fritz Blau and Hermann Remane, adapted the osmium lamp process (they worked for Welsbach) by making a filament from an osmium and tungsten mix. They soon changed their "Osram" lamp filament to tungsten only. (The German word for tungsten is <I>wolfram</I>.)
label: Description
content: All three filaments were brittle and collectively known as "non-ductile" filaments. Individual filaments could not be made long enough to give the proper electrical resistance, so lamps needed several filaments connected end-to-end. U.S. companies quickly licensed rights to all of the non-ductile patents. This particular lamp was made under license by General Electric and sent to the National Bureau of Standards for use as a standard lamp.
label: Description
content: Lamp characteristics: Medium-screw base with glass insulator. Five single-arch tungsten filaments (in series) with 5 upper and 8 lower support hooks. The stem assembly features soldered connectors, Siemens-type press seal, and a cotton insulator. Tipped, straight-sided envelope with taper at neck.
place: label: Place Made
content: United States: New Jersey, Harrison
label: Place Made
content: United States: District of Columbia, Washington
setName: label: See more items in
content: Work and Industry: Electricity
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content: Energy & Power
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content: Measuring & Mapping
label: Exhibition
content: Lighting a Revolution
label: Exhibition Location
content: National Museum of American History
publisher: label: Related Publication
content: Bright, Jr., Arthur A.. The Electric-Lamp Industry: Technological Change and Economic Development from 1800 to 1947
label: Related Publication
content: Lighting A Revolution exhibition website
label: Related Web Publication
content: http://americanhistory.si.edu/lighting/
creditLine: label: Credit Line
content: from the U. S. Department of Commerce, National Institute of Standards & Technology
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1992.0342.16
label: catalog number
content: 1992.0342.16
label: accession number
content: 1992.0342
objectType: label: Object Name
content: incandescent lamp
physicalDescription: label: Physical Description
content: tungsten (overall material)
label: Physical Description
content: glass (insulator material)
label: Physical Description
content: brass (base material)
label: Physical Description
content: cotton (insulator material)
label: Measurements
content: overall: 5 1/4 in x 2 3/8 in; 13.335 cm x 6.0325 cm