A polished brass three-circle vernier sextant (170mm radius), swivel magnifier, the main brass scale signed and numbered 'E.R. Seckel & Co. Rotterdam No 1963', inset silver scale divider 5 -0 -150, index mirror with coloured shades, the horizon glass with reflecting mirror only and coloured shades, lacking inverting sun telescope and drawer of star telescope in fitted mahogany carrying box, with certificate dated 'Rotterdam 1922'