Mercury Thallium Lamp

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Description (Brief)
Experimental mercury-thallium lamp. The quartz arc-tube has a white coating on both ends to protect against the heat.
Currently not on view
date made
ca 1970
Westinghouse Electric Corporation
Physical Description
mercury (overall material)
thallium (overall material)
overall: 16.5 cm x 3.5 cm; 6 1/2 in x 1 3/8 in
ID Number
accession number
catalog number
Credit Line
from Daniel A. Larson
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Work and Industry: Electricity
Electric Lamps
Energy & Power
Data Source
National Museum of American History


Hi Just wondered what color light does this lamp emit?
"According to Dr. Larson the light was predominately green. During an interview conducted when I collected this experimental lamp, he noted: "I thought it would be a great lamp for lighting in the parks and stuff like that because it was 85 lumens per watt, and green. But the [Westinghouse] Lamp Division had gotten burned in the fluorescent field just shortly before that on a fluorescent lamp which had a little more green in it [so they] didn't like green and at that time or shortly after that GE came out with [high pressure sodium lamps]. " Larson and colleagues in 1966 submitted a report to the US Army on thallium-iodide mercury tubes to be used as laser pumps. They reported that those tubes gave a very strong spectral line at 5350 angstroms that overwhelmed the mercury lines."

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