Felsenthal FAE-21A Artillery Protractor
date: label: date attributed by donor
content: 1950
label: date made
content: 1960s
name: label: maker
content: Felsenthal Instrument Co.
notes: label: Description
content: This clear plastic semicircular protractor is divided by tens and marked by hundreds from 100 to 3,100 mils and from 3,300 to 6,300 mils. Mils are units used in artillery and other military applications; 1,000 mils is equivalent to 56.25°. A pinhole is at the origin point. A second hole with diameter 3mm appears just above the origin point. The bottom edge of the protractor is divided by hundreds and marked by thousands from 5,000 to 0. A vernier appears to the right of the scale. The scale is labeled: 1/25,000 METERS. Superimposed on the scale is a second scale, divided by two hundreds and marked (in red) by two thousands from 0 to 10,000. A vernier appears to the left of that scale, which is labeled (in red): 1/50,000 METERS. The red markings are significantly faded.
label: Description
content: The interior of the protractor has a relatively small semicircular opening with a groove parallel to the origin point. Below the opening is a maker's mark: 12 INCH (/) FELSENTHAL INSTRUMENTS CO. (/) CHICAGO (/) FAE-21A. The letters U.S. are printed above the origin point. Donor Ben Rau dated the object to 1950, but the form of the signature indicates the protractor was probably manufactured for the U.S. Army in the 1960s.
label: Description
content: This protractor is very similar to 1977.1141.12. See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.05, 1977.1141.08, 1977.1141.09, 1977.1141.10, 1977.1141.11, 1977.1141.18, 1977.1141.19, 1977.1141.20, 1977.1141.21, 1977.1141.22, 1977.1141.23, 1977.1141.24, 1977.1141.30, and 1977.1141.39.
label: Description
content: Reference: Copyright Office, Library of Congress, "Books and Pamphlets," <I>Catalog of Copyright Entries</I>, 3rd ser., 16, part 1, no. 2 (1964): 1392.
label: Location
content: Currently not on view
topic: label: Subject
content: Mathematics
label: Subject
content: Protractor
label: Subject
content: Artillery
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
label: See more items in
content: Protractors
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: 1977.1141.23
label: accession number
content: 1977.1141
label: catalog number
content: 336407
objectType: label: Object Name
content: protractor
physicalDescription: label: Physical Description
content: plastic (overall material)
label: Measurements
content: overall: .2 cm x 30.5 cm x 16.5 cm; 3/32 in x 12 in x 6 1/2 in