Bowl-Grey painted brass, two filler plugs at side, expansion chamber at base. Bottom of bowl glazed and fitted with socket to take electric lamp. fitted with high-domed verge glass which has a brass spigot at top, on which an azimuth mirror can be located. Brass verge ring graduated to 360 degs. Inside of bowl painted black. The bowl contains an inner bowl containing the card, gimballed and sprung in the outer bowl. The inner bowl has four black lubber lines carried on white plastic strips, and is free-flooding.
Card-Dia. 7" (17.8cm) metal (?) card, white with black markings, graduated to 360 degs. with a second set of mirrored graduations 180 degs. out of phase. N point indicated by a rayed globe. Attached to large black float at centre.
In wooden transit box 14.6 x 14.4 x 12.5" (37 x 36.5 x 31cm)