Liquid compass
Bowl: Brass, filler plug at base of bowl, a syphon tube expansion chamber also fitted to base. Inside of bowl painted white. A directional arrow is fitted across diameter below verge glass. At cente of arrow is fitted a cup which engages top of spider, to prevent it lifting off pivot.
Card: Wire spider of four elements which are bent upwards at tips. N point indicated with a cross.
Needle: Two needle magnets fitted below the spider. Centre of spider fitted with cone-shaped float.
Pivot: Unsighted but thought to be of inverted type with pivot point housed in float, engaging in cap on stem whcih is carried on bridge attached across base of bowl.