An early 19th Century double 'T' frame ebony and brass octant signed on the index arm W.& S. JONES 30 HOLBORN LONDON, with telescope mount, three shades, mirrors, the index arm with framed vernier scale, tangent screw and clamp, the arc with insat bone scale divided 0°-130°, on three brass pillar legs - 13¾in.(34cm.)wide