Object Details
- 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
- Data Source
- National Museum of American History
- maker
- Gilkerson, James
- date made
- ca 1815
- Credit Line
- Gift of Mrs. Ada B. Richey
- 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
- Object Name
- protractor
