Bowl- Brass, fitted with a glass bottom and has a heavy balancing ring inside of bowl. Inside of bowl is painted white. Four lubber lines are deeply scribed into side of bowl. The verge glass has corresponding lubber lines scribed on the underside of glass in the form of a cross. A card lifter is fitted whcih raises card from jewel cup when necessary. Mounted in gimbal in a wooden box 9.75" x 9.75" x6.75" ( 24.8 x 24.8 x 17.2cm). One side fo which has asocket for a lamp. A curved metal plate slopes upwards from the lower edge of lamp aperture, this and interior of box are painted white to reflect light through bottom of bowl to card. Two brass carrying handles and two arms to lock gimbals are fitted to box.
Card- Diameter 5.5"(14.0cm) Mica, covered with paer, white with black markings, graduated quadrantally in degrees and to1/2 points. North point marked by a star and a crown and anchor device. On underside of card at E & W points are two brass weights.
Needle- Flat bar-type 5.5" (14cm) long with expanded centre through which the long steel spindle (acting as the axis or pivot) passes.
Pivot- Double pivot ar axis type. The long steel spindle passing through needle engages at the lower end in a jewel cap mounted in a brass collar attached to bottom glass of bowl; the upper end engages in a brass collar at the centre of a brass strap under verge glass.