Bowl-Dia. 7.7" (19.4cm) black painted copper with heavy lead balancing weight attached around base. Inside of bowl painted black fitted with a lubber line scribed on a brass plate which forms part of the card stop mechanism, operated by a brass lever attached to outside of bowl. Base of bowl coned to acommodate heavy brass pivot mount at centre of box, on which the bowl can be rotated in azimuth.
Card-Dia. 6.9" (17.5cm). Paper, black with white markings, graduated to 32 points with decorated North and East points. The edge of card carries a silvered metal ring, graduated quadrantally in degrees. A blob of sealing wax for balancing is attached to back. A brass pivot cap is mounted at centre.
Needle-Length 6.75" (17.3cm) edge bar type with expanded centre, through which is screwed a conical brass pivot cup. Carries a sliding brass balancing weight.
Pivot- Black painted metal conical pivot mount attached to base of bowl, carries the pivot which engages in cup at centre of card.
Box 11.5 x 11.5 x 9" carries a lubber line engraved on an ivory plate attached to edge.