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Dry card compass
Bowl: Copper with brass rim. Black painted lubber line. Card lifter operated by screw mounted on side of bowl. Mounted in brass gimbal ring on Y stand. Glazed verge ring with centre spigot for azimuthal circle. Verge ring graduated to 360 degrees.
Card: Mica covered with paper. Black with blue markings gradusted to 1/4 points and quadrantally in degrees. Large hole at centre to accommodate jeweled pivot cap. Diameter 7.6" (19.3 cm)
Needle: Four edge bar needles mounted on frame which incorporates pivot, attached to base of card.
Pivot: Steel tipped brass spike in brass mounting secured to base of bowl. Has sleeved operated card lifter.
Azimuth circle: Fitted with two verniers. One prismatic sight with two filters. Other sight slit and broken thread and the other ground glass mirror.
Mounted on ACO stand
Diam. 13.5" (34.3 cm)
O.A. Height 18.25" (46.4 cm)
Card: Mica covered with paper. Black with blue markings gradusted to 1/4 points and quadrantally in degrees. Large hole at centre to accommodate jeweled pivot cap. Diameter 7.6" (19.3 cm)
Needle: Four edge bar needles mounted on frame which incorporates pivot, attached to base of card.
Pivot: Steel tipped brass spike in brass mounting secured to base of bowl. Has sleeved operated card lifter.
Azimuth circle: Fitted with two verniers. One prismatic sight with two filters. Other sight slit and broken thread and the other ground glass mirror.
Mounted on ACO stand
Diam. 13.5" (34.3 cm)
O.A. Height 18.25" (46.4 cm)
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Object Details
| ID: | ACO0104 |
|---|---|
| Type: | Dry card compass |
| Display location: | Not on display |
| Creator: | Gilbert & Sons |
| Date made: | circa 1845 |
| Credit: | National Maritime Museum, Greenwich, London, Admiralty Compass Observatory |
| Measurements: | Overall: 370 mm; Diameter: 340 mm |
| Parts: | Dry card compass |