Vernier Octant by John Todd, London.c.1850
An eleven inch radius vernier octant by John Todd with ebonised wooden frame with inset ivory scale marked from 0 – 100 degrees with inset makers ivory plaque.
Laquered brass index arm, pinhole sights, mirrors and shades contained within a stepped ebonised box with embossed lock plate. C.1850
‘Watchmakers and clockmakers of the world’ by Brian Loomes lists John Todd as working in London from 1780.