Felsenthal FAE-28 Artillery Protractor

This clear plastic circular protractor is divided by tenths and marked by ones from 1 to 63. In the 48-64 quadrant, it is also marked in red print by ones from 32 to 17. The scale is labeled: AZIMUTH-MILS (100). The interior of the 16–32 quadrant is cut out. Each of the straight sides bears a scale divided by fifties and marked by thousands from 0 to 4,000. The scales are labeled: METERS RF 1: 50,000.
An arm extending from the 0-16 quadrant is divided by tenths and marked by ones from 1 to 17. The scale is labeled: RANGE METERS (1000). The interior of the 32–48 quadrant bears a maker's mark: FELSENTHAL INSTRUMENTS CO. (/) MFR'S CODE 22040 (/) MFR'S PART NO. FAE-28. The protractor was used to predict the direction and distance of artillery rounds. Donor Ben Rau wrote "Massengale" (which may refer to a particular U.S. Army officer) on the tag he provided with this instrument, and he dated the object to 1966.
See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.08, 1977.1141.09, 1977.1141.10, 1977.1141.11, 1977.1141.12, 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.
Currently not on view
Object Name
date attributed by donor
Felsenthal Instrument Co.
Physical Description
plastic (overall material)
overall: .2 cm x 47 cm x 21.5 cm; 3/32 in x 18 1/2 in x 8 15/32 in
place made
United States: Illinois, Chicago
ID Number
accession number
catalog number
Science & Mathematics
See more items in
Medicine and Science: Mathematics
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of Ben Wharton Rau and Margery Felsenthal Rau
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