Liquid compass - submarine

Bowl: Grey painted brass, filler plug at side, expansion chamber at base incorporated with glazed bottom of bowl. Inside of bowl painted white with a black wire lubber pointer projecting from side. Mounted in a grey-painted brass gimbal ring 6.5" (16.5 cm) dia.
Card: Dia. 3.25" (8.2 cm) white painted mica with clear edge, black markings, graduated to 16 points, quadrantally in degrees, and to 360 deg. Attached to a white-painted float at centre.
Needle: 2 x 2.0" (5.1 cm) of circular section, mounted below float.
Pivot: Brass pivot stem secured at centre of bridge mounted across base of bowl, carries a pivot point which engages in jewelled conical pivot cup at centre of float.
O.A. Height 3.25" (8.2 cm)
In wooden box 7.2" x 7.2" x 5.25" (18.2 x 18.2 x 13.4 cm)