Rectangular Protractor Signed by Gilkerson

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Description
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.
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.
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.
See also MA.335349 and MA.321014.
Reference: Gloria Clifton, Directory of British Scientific Instrument Makers 1550-1851 (London: National Maritime Museum, 1995), 113.
Location
Currently not on view
date made
ca 1815
maker
Gilkerson, James
place made
United Kingdom: England, London
Physical Description
ivory (overall material)
Measurements
overall: .2 cm x 15.2 cm x 4.4 cm; 3/32 in x 5 31/32 in x 1 23/32 in
ID Number
MA.321754
accession number
243754
catalog number
321754
Credit Line
Gift of Mrs. Ada B. Richey
subject
Mathematics
Protractor
Drafting, Engineering
See more items in
Medicine and Science: Mathematics
Protractors
Science & Mathematics
Trigonometry
Data Source
National Museum of American History, Kenneth E. Behring Center

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