Bowl-Dia. 7.1" (18.1cm) Red painted copper with lead balancing weight attached to underside and a glazed top. Inside of bowl painted white with two black lubber lines painted on side 180 degs apart. Brass pivot stem with steel point mounted at cnetre of base. Mounted in a brass gimbal ring 8.75" (22.5cm).
Card-Dia. 6.22 (15.7cm) Mica covered with paper, black with white markings. Graduated to 1/4 points. Brass jewelled pivot cap mounted at centre. Blob of sealing wax for balancing on back of card.
Needle-Length 6" (15.2cm) Single flat bar needle with expanded centre, to accommodate the brass pivot cap.
Pivot-Brass pivot stem with steel point mounted at centre at base of bowl.