Aircraft liquid compass. Chetwynd's Patent.
Bowl: Black painted brass, filler plug at side, expansion chamber at base. Inside of bowl painted white. A black wire lubber line projects from side of bowl. Mounted in outer black painted metal casing diameter 5.75" (14.6cm) by two U-shaped sockets lined with rubber into which two trunnions on the bowl engage. The space between bowl and casing is packed with horse-hair to damp out vibrations.
Card: Diameter 3" (7.8cm) Mica? Black with white markings, graduated to 360 degrees. A band running across card and float from N to S is painted red and blue, another running from E to W is painted white.
Needle: Two magnets are attached to underside of card.
Pivot: Unsighted, stem secured to bridge mounted across base of bowl. Point said to engage in jewel cap fitted to float. O.A Height 3.15" (8.0cm)