W & S Jones of Holborn London 1800 Drum box Sextant Original lacquer
W & S Jones invented the drum sextant in 1797 and it was still being made by Stanley in 1900 with modifications. I have no idea how it works. This appears to be an early example by Jones with its original lacquer which is worn in places. Appears to have lost some silver from its' internal mirrors as one would expect with its 200 or so years. Its' owner has engraved a note on the face'add 8'. One of two small grub screws is missing which holds one of the internal mirrors in place. A blank hole can be seen on the face - lower left of the first image - where the screw is missing.