Dry compass

Card-Mica covered with paper, black with white and black markings, graduated to 1/4 points and quadrantally in degrees. Card has 2" dia. hole at centre fitted with rubber disc in which pivot cap is set.
Needle-Four edge bar needles, 2 x 7.15". 2 x 5.25" in length, attached to card by a brass ring. A brass strut with two balance weights is fitted across the diameter of ring.
Pivot- The central aperture in card carries a brass ring in which is fitted a rubber disc at the centre of which is set a cone-shaped jewel cap.

Object Details

ID: ACO0985
Type: Dry compass
Display location: Not on display
Creator: Unknown
Date made: circa 1860
Credit: National Maritime Museum, Greenwich, London, Admiralty Compass Observatory
Measurements: Overall: 20 mm; Diameter: 190 mm