Rectangular Protractor Signed by Gilkerson
date: label: date made
content: ca 1815
name: label: maker
content: Gilkerson, James
notes: label: Description
content: This ivory rectangular protractor is graduated by single degrees and marked by tens from 10° to 170° in both directions, clockwise and counterclockwise. The front of the protractor also contains a diagonal scale. There is a maker's mark: Gilkerson Tower-hill London. James Gilkerson & Co. was in business in Tower Hill, London, from 1809 to 1825.
label: Description
content: The back of the protractor contains architect's scales of equal parts (dividing the inch into 60, 50, 45, 40, 35, and 30), a scale of cosines, and a "universal scale," including chords, rhumbs, latitude, longitude, sines, seconds, inclined meridian, tangents, and hours. These scales suggest the protractor was intended for navigational use.
label: Description
content: Donor Ada B. Richey reported that her husband's ancestor, Lt. Col. Alexander Matheson (b. 1788), was the original owner of this drawing instrument. He settled in Perth, Canada, after serving in the British military during the War of 1812.
label: Description
content: See also MA.335349 and MA.321014.
label: Description
content: Reference: Gloria Clifton, <I>Directory of British Scientific Instrument Makers 1550-1851</I> (London: National Maritime Museum, 1995), 113.
label: Location
content: Currently not on view
place: label: place made
content: United Kingdom: England, London
topic: label: Subject
content: Mathematics
label: Subject
content: Protractor
label: Subject
content: Drafting, Engineering
setName: label: See more items in
content: Medicine and Science: Mathematics
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content: Science & Mathematics
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content: Trigonometry
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content: Protractors
creditLine: label: Credit Line
content: Gift of Mrs. Ada B. Richey
dataSource: label: Data Source
content: National Museum of American History
identifier: label: ID Number
content: MA.321754
label: accession number
content: 243754
label: catalog number
content: 321754
objectType: label: Object Name
content: protractor
physicalDescription: label: Physical Description
content: ivory (overall material)
label: Measurements
content: overall: .2 cm x 15.2 cm x 4.4 cm; 3/32 in x 5 31/32 in x 1 23/32 in