Pocket double box sextant of 2½-inch radius, designed by Captain Christopher George (Trade Mark No.31) with two circular lacquered brass plates and two lids, by the company of, William Cary, Strand, City of Westminster, London, England, 1835-1845. Fitted with two Inlaid silver scales 135° and 123° (-5° to 150°) with 30 arc-minute divisions and a silver vernier with 1 arc-minute divisions and index arms rotated by milled knobs on the upper and lower plates. The index glass is fixed with adjustment for the horizon glass and a single lens magnifier is hinged on a swivel arm (40 mm) with choice of large and small pinholes Double box sextant. 1835-1845
Surveyor's pocket box sextant with leather case, made by John Dennett Potter, Poultry, City of London, London, England, 1855-1865. Consists of two circular lacquered brass plates with lid that acts as a handle when used. Fitted with Inlaid silver 134° scale (-5° to 160°) with 30' divisions and a silver vernier (1' div.). The index arm is rotated by a milled knob on the upper plate with two filter shades (red & green) operated by lever. The index glass is fixed with adjustment for the horizon glass. Fitted with magnifier (single lens) on hinged 40 mm swivel arm and choice of a large and a small pinhole sight but telescope missing. Marked ‘H O’ the property mark of the Hydrographic Office of the British Admiralty. Box type pocket sextant with case. 1855-1865
Photograph of Amsler current meter by Stanley, 1915 Photograph of Amsler current meter by Stanley 1915
Prismatic magnetic compass, Verner type pattern, Mk VIII, adapted for night marching, unsigned, British, 1918 Prismatic magnetic compass, British, 1918 1918