A very good original WWI oxidised brass box or pocket sextant in leather case by Troughton & Simms No 3543 c1918

Box sextant constructed between twin plates in the form of a low cylinder, the silvered scale from 0° to 140° degrees with 1° and ½° increments, vernier to 30 arc minutes. Milled knobs to shipped mirror adjustment tool and setting key, swinging arm mounted scale magnifier. Marked with military broad arrow, the maker “Troughton & Simms Ltd, London,” serial “No. 3543,” and “1918.” Pin hole sight to blind, red and green shades with activation port and dust shutter to rear. Mirror azimuth and declination adjustment squares. Bayonet fixing drum cover, which also functions as a handle, with paper insert displaying natural tangents protected by tracing paper to inner lid. Top lid with small brass handle, also marked with military broad arrow, the maker, serial number and date.

In original dark brown leather carry case marked “D. Mason & Sons Ltd, Birmingham,” “1918” and carrying the military broad arrow.

Condition: The brass case retaining almost all of its original oxidised finish with marks commensurate with age and use, the paper inset with some foxing. The mirror bright, the shades clear. Mechanically the instrument functions perfectly. The leather case in very good original condition, the straps sound.

Comments: These original box sextants are hard to find in good condition, particularly with the leather case.

A particularly crisp example of an original WWI instrument.