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This octant has an ebony frame, reinforced brass index arm, and telescopic sight. The ivory scale is graduated every 20 minutes from -2° to +111° and read by vernier and tangent screw to single minutes of arc. The "E. & G. W. BLUNT, New York" inscription may indicate that it was made after 1857 when the Blunts began offering nautical instruments "of American manufacture," and before 1866 when the firm became Blunt & Nichols.
The inscription on the brass nameplate reads: "George Davidson. Philadelphia, Pa." George Davidson (1825-1911) was a surveyor, geodesist and astronomer affiliated with the U.S. Coast Survey.
Ref: Deborah J. Warner, "American Octants and Sextants: The Early Years," Rittenhouse 3 (1989): 86-112, on 91-92.
"George Davidson," American National Biography, vol. 6, pp. 143-144.
Currently not on view
Object Name
date made
mid 19th century
E. & G. W. Blunt
place made
United States: New York, New York City
radius: 11 in; 27.94 cm
overall: 3 in x 11 1/8 in x 12 1/4 in; 7.62 cm x 28.2575 cm x 31.115 cm
ID Number
catalog number
accession number
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Medicine and Science: Physical Sciences
Measuring & Mapping
Data Source
National Museum of American History
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