Liquid compass
Bowl: Brass, painted black, filler plug at side, expansion chamber at base of bowl. Bowl mounted in outer casing (diameter 6" (15.2cm) the bottom of which is fitted with a vibration damping material. Inside of compass bowl painted white. Fitted with a black wire lubber line. a white plastic (?) bridge is fitted across the diameter of the bowl, which accommodates an inverted pivot at centre (unsighted). Verge ring fitted with a narrow rotating ring, the purpose of which is unknown. Prism card magnifier attached to foreside of bowl.
Card: White with red markings on north half and black markings on south half. Graduated 1-35 (to 360 degrees) with mirror engraved graduation at edge of card.
Needle: Two needles slung beneath card.
Pivot: Of the double pivot type, one pivot carried in the upper plastic bridge, which engages in the top of card, the lower pivot (unsighted) is assumed to be attached to base of bowl.