Semicircular Protractor
date: label: date made
content: 19th century
notes: label: Description
content: 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 degree lines are crude and likely engraved by hand rather than by machine. A rounded notch is at the origin point. There is no maker's mark. The Department of Entomology in the National Museum of Natural History acquired this object in the late 19th century for use in research. Since inexpensive (10–25 cents) machine-divided brass protractors were widely available during this time period, it is not clear why the curators purchased an instrument that was so poorly manufactured. The protractor may have been made closer to the late 18th century.
label: Location
content: Currently not on view
topic: label: Subject
content: Mathematics
label: Subject
content: Protractor
label: Subject
content: Entomology
setName: label: See more items in
content: Medicine and Science: Mathematics
label: See more items in
content: Science & Mathematics
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content: Protractors
creditLine: label: Credit Line
content: Transfer from National Museum of Natural History
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: 1990.0099.04
label: accession number
content: 1990.0099
label: catalog number
content: 1990.0099.04
objectType: label: Object Name
content: protractor
physicalDescription: label: Physical Description
content: brass (overall material)
label: Measurements
content: overall: .1 cm x 9.5 cm x 4.7 cm; 1/32 in x 3 3/4 in x 1 27/32 in