Siemens & Halske tantalum filament lamp
date: label: Date made
content: ca 1907
label: date made
content: ca. 1907
name: label: maker
content: Siemens & Halske
notes: label: Description
content: By the late 1890s, carbon filament lamps were no longer the hand-made devices demonstrated by Thomas Edison. He and many others had refined them into mass-produced, reliable products. But the energy efficiency of carbon lamps remained poor, leading researchers—especially in Europe—to seek better filament materials. In 1902 Germans Werner von Bolton and Otto Feuerlien invented a filament made from element number 73, tantalum. Tantalum lamps produced 5 lumens per watt (lpw), much better than the 3.2 lpw of the carbon lamps of that day.
label: Description
content: The electrical resistance of tantalum was lower than carbon, though. In order for the total resistance of a tantalum lamp to match the total resistance of a carbon lamp, it had to have a much longer filament. In order to support the longer filament inside a bulb of reasonable size, von Bolton and Feuerlien used a series of hooks attached to the lamp's central glass stem. The filament wound up and down within the bulb. Though the design looked complex, it worked well and was later adopted for the tungsten filaments that replaced tantalum around 1910.
label: Description
content: This particular lamp was made by the inventors' employer, Siemens and Halske. Tantalum lamps became the first metal filament lamps offered for sale in the U.S. and in 1909 became the first lamps to carry the trade-name Mazda.
label: Description
content: Lamp characteristics: Brass medium-screw base with skirt and porcelain-dome insulator. A tantalum filament with 11 upper and 10 lower support hooks. The support hooks are angled in order to keep tension on the filament, which tended to sag during operation. The stem assembly features soldered twist and crimp connectors, a Siemens-type press seal, and a cotton insulator. Tipped, straight-sided envelope.
setName: label: See more items in
content: Work and Industry: Electricity
label: See more items in
content: Energy & Power
label: Exhibition
content: Lighting a Revolution
label: Exhibition Location
content: National Museum of American History
publisher: label: Related Publication
content: Duncan, Robert Kennedy. Some Rare Elements and Their Application
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 General Electric Company
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: EM.239147
label: catalog number
content: 239147
label: accession number
content: 46578
objectType: label: Object Name
content: incandescent lamp
label: Other Terms
content: incandescent lamp; Lighting Devices; Edison; Cage; Metal
physicalDescription: label: Physical Description
content: tantalum (overall material)
label: Physical Description
content: glass (overall material)
label: Physical Description
content: brass (overall material)
label: Physical Description
content: porcelain (overall material)
label: Physical Description
content: cotton (overall material)
label: Measurements
content: overall: 4 3/4 in x 62 3/8 in; 12.065 cm x 158.4325 cm