Bowl - Black painted brass, filler plug at side, expansion chamber at base incorporated with glazed bottom bowl. Inside of bowl painted white, fore side fited with a 5" curved mirror with black wire lubber line attached, aft side fitted with a 3" curved mirror with a similar lubber line (these mirrors are to reflect the graduations on the edge of card). Mounted in black painted brass gimbal ring 12.25" diameter.
Card - Dia. 6" (15.2cm) Mica (?) painted white with black markings, graduated to 32 points, quadrantally in degrees and to 360 degs. Black painted float dome at centre. Outer edge of card turned down and carries graduations to 360 degs. These graduations are reflected by the two mirrors fitted in bowl.
Needle- Two 4" needles of circular section mounted below card, one either side of pivot.
Pivot -Unsighted but stem can be seen attached to a bridge mounted across bottom of bowl.