Worthington & Allan London, with four shades, mirrors, the index arm with framed vernier, tangent screw and clamp, the arc with inset bone scale divided 0-90°, with ebony carrying handle on three brass pillar feet - 9¾in.(24.5cm)wide (sight missing and damaged)" /> A 19th Century "T" framed brass and ebony Octant, signed on the arc <I>Worthington & Allan London</I>, with four shades, mirrors, the index arm with framed vernier, tangent screw and clamp, the arc with inset bone scale divided 0-90°, with ebony carrying handle on three brass pillar feet - 9¾in.(24.5cm)wide (sight missing and damaged) | Christie's