Bowl-Black painted brass, filler plug at side. Base of bowl fitted with a glycerine filled domed glass balancer. Inside of bowl painted white with four black wire lubber pointers projecting from side.Verge ring graduated 0-180 degs. The verge glass is fitted with a socket at its centre to accommodate an azimuth instrument. Fitted with fore-and-aft gimbal pivots.
Card-Dia.6.5" (16.5cm) Mica(?), outer edge painted white with black markings, graduated quadrantally in degrees and to 360 degs. Inner portion of card painted black. Attached to a small black float at centre.
In wooden box 11.4 x 11.4 x 8.6" (29 x 29 x 22cm)