Details
A rare mid-late 18th Century mahogany vernier octant
the ivory makers plaque engraved Made by Francis Watkins LONDON for Amos Sparkes 1779, the scale divided 5°- 0°- 95°, vernier divided 10 - 0 - 10 with fine screw adjustment, double pin hole sight, set of three shades, three mirrors and pencil in centre of 'T' frame, the reverse with brass pins for standing and inlaid ivory jotter, the arc -- 16½in. (42cm.); the index arm -- 19in. (48cm.)
See illustration