A three-circle oxidized brass frame vernier sextant signed and numbered on the main arc J. Coombes, Optician & Instrument Maker, Devonport 9659, the index arm inscribed G.F. Blyth R.N. and with swivel magnifier, inset scale divided 0 - 5 - 130, four shades to index mirror, three shades to horizon mirror, sun inverting telescope, star telescope and draw tube (all numbered 9659), in fitted mahogany carrying box with National Physical Laboratory Class A Certificate of Examination dated October 1915 -- 11¼in. (26cm.) wide