Bowl - Black painted brass, filler plug at side, expansion chamber at base. Bottom of bowl glazed. Base of bowl fitted with a heavy outer casing. Inside of bowl painted white, fore side fitted with a 4" curved mirror with a black wire lubberline attached (the mirror is ude to reflect the graduations on edge of card). Mounted in black painted brass gimbal ring 12" diameter.
Card - Diameter 6" (15.2cm) Mica (?) painted white with black markings, graduated to 1/4 points and quadrantally to degrees. White painted float dome at centre. Outer edge of card turned down and carries graduations quadrantally in degrees. These graduations are reflected in mirror.
Needle- Two 4" needles of circular secton mounted below card, one either side of pivot.
Pivot -Unsighted but stem can be seen attached at centre of bottom glass of bowl.