Cooper Hewitt U-shaped mercury vapor lamp
date: label: Date made
content: ca 1904
label: date made
content: ca. 1904
name: label: maker
content: Cooper Hewitt Electric Company
notes: label: Description
content: Many inventors worked to improve incandescent lamps during the 1890s, but only a few tried to develop practical discharge lamps. Unlike incandescent lamps that make light by heating a filament until it glows, discharge lamps make light by passing an electrical current through a gas. The current energizes the gas which then emits light. One inventor, Peter Cooper Hewitt, achieved success with a discharge lamp using mercury.
label: Description
content: Hewitt experimented with mercury-filled tubes in the late 1890s and found they emitted an unappealing bluish-green light. The amount of light given off, however, was startling. In 1902 the Cooper Hewitt Vapor Lamp Company (backed by George Westinghouse) was established to make the lamps. Though few people would want his lamps in their homes, Hewitt realized that the poor color would not matter for other uses. Photo studios used Cooper Hewitt lamps extensively. In an age of black and white film, the color of a photographer's light made little difference--they just needed lots of light. Industrial uses for the lamp also emerged.
label: Description
content: Ultimately, Cooper Hewitt lamps proved cumbersome. A heavy ballast was needed to control the electrical current and each lamp contained nearly 1 pound of mercury. Starting early models required the user to tip the entire fixture over so that the mercury would run from one end to the other. Tungsten-filament incandescent lamps made in the 1910s provided almost as much energy efficiency as Cooper Hewitt tubes and gave a much better color. General Electric bought the Cooper Hewitt Company in 1919, and in 1933 began marketing a more convenient mercury lamp, the H-1. The H-1 and fluorescent lamps used only a fraction of the mercury found in Cooper Hewitt lamps, but produced light much more efficiently.
label: Description
content: This unit is a production-model Cooper Hewitt lamp from about 1904. An attached manufacturer's tag (not shown) gives proper operating positions for various models, and includes a caution notice and a six month warranty.
label: Description
content: Lamp characteristics: Glass, U-shaped tube with bulbs at both ends. Bulbs house mercury-pool electrodes. A single brass screw contact is mounted on the smaller bulb; two brass screw contacts are on the larger bulb. The tube is attached to a mounting bracket that holds it in its fixture. Pads of asbestos insulation keep the glass from direct contact with the metal bracket. Unit contains about 1 pound (.5 kilograms) of mercury.
label: Description
content: Cooper Hewitt U-shaped mercury vapor lamp. Cooper-Hewitt Company, U-tube configuration. Attached manufacturer tag shows proper operating position for various models, caution notice, corporate address, and notes a 6 month warranty.
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: 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 Osram Sylvania Inc., thru Richard H. Dowhan
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1998.0005.10
label: catalog number
content: 1998.0005.10
label: accession number
content: 1998.0005
objectType: label: Object Name
content: discharge lamp
physicalDescription: label: Physical Description
content: mercury (overall material)
label: Physical Description
content: glass (overall material)
label: Physical Description
content: metal (overall material)
label: Measurements
content: overall: 26 1/2 in x 7 1/2 in x 3 1/2 in; 67.31 cm x 19.05 cm x 8.89 cm