Compass card
Card for a dry card compass
Card: Mica covered with paper. Brown with black markings graduated to quarter points and 0 - 180 East and West of North Point. Hollow centre with angled brass bridge holding screw in pivot spike. Has two slits for needles to move in.
Needle: Two edge bar needles mounted on brass framework. Both swing from individual centres thus allowing amount of dip to be seen. 7" long by 0.4" deep.
Pivot: Brass and steel spike mounted on brass bridge on centre of card.
Card: Mica covered with paper. Brown with black markings graduated to quarter points and 0 - 180 East and West of North Point. Hollow centre with angled brass bridge holding screw in pivot spike. Has two slits for needles to move in.
Needle: Two edge bar needles mounted on brass framework. Both swing from individual centres thus allowing amount of dip to be seen. 7" long by 0.4" deep.
Pivot: Brass and steel spike mounted on brass bridge on centre of card.
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Object Details
ID: | ACO1005 |
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Type: | Compass card |
Display location: | Not on display |
Creator: | Keen, R. J. |
Date made: | Mar 1854 |
Credit: | National Maritime Museum, Greenwich, London, Admiralty Compass Observatory |
Measurements: | Overall: 35 mm; Diameter: 215 mm |