A Hezzanith "Endless Tangent Screw" lattice frame vernier sextant (170mm radius) the brass main arc signed and numbered 'Heath & Co. New Eltham, London S.E. 3 Y588' made for 'F. Robson and Co. Newcastle-On-Tyne' inset silver scale divided 5 - 0 - 155 , sun inverting and star telescopes, coloured shades to index and horizon mirrors, with other accessories in fitted mahogony box, Heath Examination Certificate of Examination dated 5 June 1929 -- 280mm wide See illustration