Semicircular Protractor

Description
This semicircular brass protractor is divided by single degrees and marked by tens from 10° to 170° in both the clockwise and counterclockwise directions. The origin point is marked with an arrow. A 2-1/2 inch ruler, divided by sixteenths of an inch, runs along the lower edge of the protractor. The letters U.S.A. are engraved above the right end of the ruler. No maker's mark is present.
Location
Currently not on view
Object Name
protractor
date made
ca 1930
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
ID Number
1981.0933.19
accession number
1981.0933
catalog number
1981.0933.19
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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