Bowl-Dia. 7.25" (18.5cm) copper with heavy lead balancing weight attached to base. Inside of bowl unpainted (with traces of white paint evident). Fitted with a lubber line consisting of a scribed line on a brass plate which form a part of the card stop mechanism, which is operated by a brass lever attached to the outside of the bowl. Mounted in a brass gimbal ring 9.25" (23.5cm) dia. carried in a brass "U" bracket having a central mounting spigot, on which the bowl can be rotated in azimuth.
Sight vanes-Two folding sight vanes are carried on abrass bar mounted across the diameter of the verge glass and secured to the brass vegre ring. One vane 4.75" (12.1cm) high, of open frame type with thread and sliding frame containing lens. The other vane 4.75" (12.1cm) high has a narrow slit and a sliding frame with coloured glass shade.
Card-Dia. 6.3" (16cm) paper covered mica, 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. Back of card carries two brass balancing weights at E & W points and several blobs of sealing wax. A brass pivot cap is mounted at centre.
Needle-Length 6.25" (15.9cm), flat bar type with expanded centre, through which is screwed a conical brass jewelled pivot cup, attached to rim of card by brass screws.
Pivot-Brass pivot stem attached to base of bowl, carries a steel pivot point which engages in the pivot cup at centre of needle.