A 12ins.(31cm)radius Ebony Octant,
by Spencer Browning & Rust, London. Reading from -5 to 95 degrees on the engraved ivory scale, the brass index arm fitted with a vernier to 20 seconds. With brass pinnule sight and back sight, horizon and back mirror, three sun shades. The frame with ivory topped pencil and rear notation plate. In an oak, stepped keystone case, bearing a Trade Plate for DM McGreggor & Co. Glasgow.