Type 6/18 Mark II

Aperiodic compass
Bowl: Brass, painted grey. Filler plug at side of bowl, expansion chamber attached to base. An aperture is provided in side of bowl for illuminating the spider. Bowl attached by three legs with pin and helical springs to a frame on which it stands. A corrector magent carrier is attached below the frame. Inside of bowl painted white. Single black lubber line attached below verge glass. Rotatable verge ring marked with a red triangle at N point and graduated 1-36 ( to 360 degs). Fitted with four parallel wires for grid steering.
Card: Spider with eight elements marked at N,E, S &W.
Needle: Six needle magnets attached below the spider.
Pivot: Brass? Pin attached to bridge which fits across base of bowl, upon which a cup at centre of spider fits.

Object Details

ID: ACO0367
Type: Aperiodic compass - aircraft
Display location: Not on display
Creator: Bennett, Dr. G. T.; Campbell, Colin
Date made: 1920
Credit: National Maritime Museum, Greenwich, London, Admiralty Compass Observatory
Measurements: Overall: 180 mm; Diameter: 152 mm