Bowl- Brass fitted with a glass bottom and has a heavy balancing ring inside of bowl. Bowl has a mica covered aperture cut in side, this is to illuminate the card. Inside of bowl painted white. Four lubber lines are deeply scribed into the side of bowl. The verge glass has corresponding lubber lines scribed on the underside of the glass in the form of a cross. A card lifter is fitted which raises card from jewel cup when necessary. Verge ring is graduated to 360 degs and an azimuth sight is attached to centre of verge glass. Sight has two folding arms; 5.75" (14.6cm) long, one with a slit and filter glass, the other with a thread. Mounted in gimbals in a wooden box; 13" x 132 x9.25" (33cm x 33cm x 23.5cm) one side of which has a socket for a lamp. A curved metal plate slopes upwards from the lower edge of lamp aperture, this and interior of box painted white to reflect light through bottom and side of bowl to the card. Two carrying handles and two arms to lock gimbals are fitted to box.
Card- Diameter 8" (20.3cm) Mica, covered with paper, white with black markings graduated quadrantally in degrees and to 1/2 points. North point marked by a star and a crown and anchor device. The centre of card has a hole 1.25" (3.2cm) in dia. to accommodate pivot mount. On underside of card at E & W points are two brass weights.
Needle- Flat bar type 8" (20.3cm) long with expanded centre, from which rises a semi-circular bridge of brass into which the inverted pivot point is screwed.
Pivot- Inverted type: brass pivot stem secured to glass of bowl. Jewel cap is mounted at top of stem. The card lifter mechanism is also mounted on the stem.
O.A. Height 16.0"(40.6cm)