Double box sextant.
Pocket double box sextant of 2½-inch radius, designed by Captain Christopher George (Trade Mark No.31) with two circular lacquered brass plates and two lids, by the company of, William Cary, Strand, City of Westminster, London, England, 1835-1845. Fitted with two Inlaid silver scales 135° and 123° (-5° to 150°) with 30 arc-minute divisions and a silver vernier with 1 arc-minute divisions and index arms rotated by milled knobs on the upper and lower plates. The index glass is fixed with adjustment for the horizon glass and a single lens magnifier is hinged on a swivel arm (40 mm) with choice of large and small pinholes
Details
- Category:
- Surveying
- Object Number:
- 1876-988
- Materials:
- casing, brass, blackened, lenses, glass and handle, walnut
- Measurements:
-
overall: 90 mm x 38 mm, 95 mm,
- type:
- double sextant and box sextant
- credit:
- Admiralty Hydrographic Department
