Semicircular Protractor Retailed by Post

Description
This semicircular brass protractor is divided by single degrees and marked by tens from 0° to 180° in both the clockwise and counterclockwise directions. The bottom edge is indented so that a pencil or pricker may be placed at the origin point. The protractor bears three marks: POSTS; MADE IN GERMANY; and a fleur-de-lis pointing to the origin. The Frederick W. Post Company, a Chicago mathematical instruments dealer established in 1893, used the type style found on this protractor in the 1920s and 1930s. However, the brass protractor depicted in Post's 1936 catalog is not indented on its lower edge, and it shows an eagle under the maker's mark.
William J. Ellenberger (1908–2008) donated this object. He studied electrical and mechanical engineering at the George Washington University between 1925 and 1934. He then worked for the Potomac Electric Power Company and the National Bureau of Standards. During World War II, Ellenburger served in the U.S. Army Signal Corps. He was a civilian construction management engineer for the army from 1954 to 1968, when he became a private consultant.
References: Frederick W. Post Company, Dependable Drawing Materials, 18th ed. (Chicago, 1936), 195; "The G[eorge] W[ashington] Engineering Hall of Fame 2006 Inductees," http://www.seas.gwu.edu/ifaf/hall_of_fame_inductees_2006.php.
Location
Currently not on view
Object Name
protractor
date made
1920-1940
maker
Frederick Post Co.
Physical Description
brass (overall material)
Measurements
overall: .1 cm x 9.5 cm x 4.5 cm; 1/32 in x 3 3/4 in x 1 25/32 in
place made
United States: Illinois, Chicago
ID Number
1981.0933.18
accession number
1981.0933
catalog number
1981.0933.18
subject
Science & Mathematics
Protractors
Mathematics
Protractor
See more items in
Medicine and Science: Mathematics
Protractors
Data Source
National Museum of American History, Kenneth E. Behring Center
Credit Line
Gift of William J. Ellenberger

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