Felsenthal FAE-6 Set Square/Coordinate Scale
date: label: date made
content: ca 1945
name: label: maker
content: Felsenthal Instrument Co.
notes: label: Description
content: On one side, this 4-3/8" white plastic L-shaped square has scales along its inner edge for reducing yards to the representative fraction (R.F.) of 1:20,000, divided to twenties and numbered by 500s from 0 to 1,000. Scales along its outer edge are for reducing yards to R.F. 1:62,500, divided to hundreds and numbered by thousands from 1,000 to 6,000. The end of one leg is marked: U.S.
label: Description
content: The other side has scales along its inner edge for reducing meters to R.F. 1:25,000, divided to twenties and numbered by 500s from 0 to 1,500. Scales along its outer edge are for reducing meters to R.F. 1:50,000, divided to fifties and numbered by thousands from 1,000 to 5,000. The end of one leg is marked: U.S. The device, also known as a "coordinate scale," was used by soldiers to compare measurements to notations on a chart in order to aim weapons. Compare to 1977.1141.16. This example was also received with a duplicate square, but the second square was broken and discarded.
label: Description
content: According to the accession file, this instrument was made for the U.S. Army by Felsenthal Instrument Company in 1945 as model number FAE-6. The company was the leading supplier of mathematical instruments to the U.S. Army Air Force and the U.S. Navy Bureau of Aeronautics, particularly during World War II (when the firm was known as G. Felsenthal & Sons). After the company ceased operations in approximately 1976, it provided a large sample of its products to the Smithsonian. The lack of any form of the firm's name on this instrument suggests it may actually have been made in the 1960s. For company history, see 1977.1141.02.
label: Location
content: Currently not on view
topic: label: Subject
content: Mathematics
label: Subject
content: Artillery
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Squares and Triangles
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content: Metric System
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content: Science & Mathematics
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content: Measuring & Mapping
creditLine: label: Credit Line
content: Gift of Ben Wharton Rau and Margery Felsenthal Rau
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1977.1141.17
label: catalog number
content: 336401
label: accession number
content: 1977.1141
objectType: label: Object Name
content: set square
physicalDescription: label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: .1 cm x 11.2 cm x 11.2 cm; 1/32 in x 4 13/32 in x 4 13/32 in