Felsenthal FAE-9A Artillery Protractor

This clear plastic rectangular protractor is divided by single degrees and marked by tens from 10° to 170° and from 190° to 350°. Pinholes near the 20° and 60° marks allow for positioning the protractor. The bottom edge is divided by tenths of an inch and marked by ones from 1" to 5". The interior of the protractor contains three scales of equal parts: 1) divided by hundreds and marked by five hundreds from 0 to 2,500 yards, for a scale of 1/20,000; 2) divided by hundreds and marked by thousands from 0 to 7,000 yards, for a scale of 1/62,500; and 3) divided by hundreds and marked by five hundreds from 0 to 2,000 meters, for a scale of 1/20,000. There are verniers to the left of the first and third scales.
Near the top of the protractor is marked: U.S. 1957. The 1957 is believed to refer to the date of the object. The maker's mark is: G. FELSENTHAL & SONS, INC. (/) PART NO. FAE-9A.
This protractor is almost exactly like 1977.1141.08. See also 1977.1141.01, 1977.1141.02, 1977.1141.03, 1977.1141.05, 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.
Reference: Deborah J. Warner, “Browse by Maker: Felsenthal,” National Museum of American History Physical Sciences Collection: Navigation, http://americanhistory.si.edu/collections/navigation/maker.cfm?makerid=173.
Currently not on view
Object Name
date attributed by donor
G. Felsenthal & Sons, Inc.
Physical Description
plastic (overall material)
overall: .3 cm x 15.2 cm x 4.5 cm; 1/8 in x 5 31/32 in x 1 25/32 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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