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Circumferentor
Graduations-Circle graduated to 360 degs. Vernier scales at each end of alidade 30-0-30.
Sights-Two detachable sight vanes 5" (12.7cm) long mounted on circle, one sight with a vertical slit with a rectangular aperture above , the other with a rectangular aperture with a vertical slit above. Two detachable sight vanes 4" (10.1cm) long, mounted on alidade, similar in description to those on circle.
Compass- Dia. 5" (12.7cm) mounted at centre of instrument. Fitted with an edge bar needle 4" (10.2cm) long, with a jewelled pivot cap at centre. Graduated to 8 points, and anti-clockwise to 360 degs.
A ball and socket joint for mounting on a tripod is contained in the wooden box.
Octagonal wooden box 12 x 12 7" (30.5 x 30.5 x 17.8cm)
In wooden box 12.75 x 12.75 x 3" ( 32.4 x 32.4 x 7.6cm)
Sights-Two detachable sight vanes 5" (12.7cm) long mounted on circle, one sight with a vertical slit with a rectangular aperture above , the other with a rectangular aperture with a vertical slit above. Two detachable sight vanes 4" (10.1cm) long, mounted on alidade, similar in description to those on circle.
Compass- Dia. 5" (12.7cm) mounted at centre of instrument. Fitted with an edge bar needle 4" (10.2cm) long, with a jewelled pivot cap at centre. Graduated to 8 points, and anti-clockwise to 360 degs.
A ball and socket joint for mounting on a tripod is contained in the wooden box.
Octagonal wooden box 12 x 12 7" (30.5 x 30.5 x 17.8cm)
In wooden box 12.75 x 12.75 x 3" ( 32.4 x 32.4 x 7.6cm)
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Object Details
| ID: | NAV1379 |
|---|---|
| Type: | Circumferentor |
| Display location: | Not on display |
| Creator: | Adams, George |
| Date made: | circa 1760 |
| Credit: | National Maritime Museum, Greenwich, London, Caird Collection |
| Measurements: | Overall: 155 mm x 257 mm x 260 mm |
| Parts: | Circumferentor |