Compass card

Dry compass

Card: Mica covered with paper, white with black markings, graduated to 1/2 points and quadrantally in degrees. N point indicated by a five-pointed star. Centre of card has a 1.2" (3.0 cm) diameter hole to accommodate curved brass pivot bridge.

Needle: 9.8" (25.0 cm) long flat bar type with pointed ends and an expanded centre. Two brass balancing weights are mounted at E & W points.

Pivot: Inverted type, having a steel pivot point screwed into the top of a brass bridge mounted above card and secured to expanded centre of needle.

Object Details

ID: ACO0867
Type: Compass card
Display location: Not on display
Creator: Unknown
Date made: circa 1825
Credit: National Maritime Museum, Greenwich, London, Admiralty Compass Observatory
Measurements: Overall: 25 mm; Diameter: 250 mm