Dry compass

Dry compass

Card: Mica covered with paper, white with black markings, graduated to quarter points and quadrantally in degrees. At centre part of card is a circle graduated in Roman numerals to 24 hours and an inner graduation quadrantal 1 - 8

Needle: Two slightly curved edge bar needles, 7.5" (19.0 cm) in length, attached to card by brass struts. A small brass balancing disc is mounted to South side of centre of card.

Pivot: Bell shaped brass pivot cup and balancing weight, fitted with jewell cal at apex of bell, attached to centre of card by a brass disc set in card. Upper part of jewel cap has a stile pin set in it, for taking bearings of the sun by its shadow cast on card.

Object Details

ID: ACO1007
Type: Dry compass
Display location: Not on display
Creator: Cameron
Date made: 1853
Credit: National Maritime Museum, Greenwich, London, Admiralty Compass Observatory
Measurements: Overall: 80 mm; Diameter: 200 mm