Bowl- Grey painted brass, with glass bottom filler plug in verge ring, large annular bubble-trap below verge ring, heavy metal weight fitted around base of bowl. Inside of bowl unpainted, two black lubber lines are carried on brass strips attached to side. The verge glass has four lubber lines in form of cross, engraved on underside. Verge ring graduated to 360 degrees. The verge glass has a brass spigot at centre to accommodate azimuth sight. Azimuth sight has two folding arms 4.5" (11.5cm) long, one arm carries a slit; the other a slit with thread. Mounted in grey painted brass gimbal ring 7.8" (20cm) in diameter in a wooden box, 9.8 x 9.8 x 8.25" (25 x 25 x 21 cm). The lid having a glazed hole at centre 7.5 (19cm) in diameter. One side of box has a socket for a lamp. A curved metal plate slopes upwards from lower edge of lamp aperture, this and interior of base painted white to reflect light to bottom of bowl. Two carrying handles and two arms to lock gimbals are fitted.
Card Diameter 5.15" (13cm) white painted mica, graduated to 32 points and to 360 degs. Has two 3.9" (10cm) cylindrical floats mounted below card.
Needles- Two contained in cylindrical floats.
Pivot -Stem secured at centre of bottom glass carries a pivot point which engages in cone-shaped jewelled pivot cup attached at centre of card by a wire framework.