Box type pocket sextant with case.

Made:: 1855-1865 in Poultry

maker:: John Dennett Potter

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.

Details

Category:: Surveying

Object Number:: 1876-989

Materials:: casing, brass, blackened, mirrors, glass and lens, glass

Measurements:: Radius: 2"
diameter 73 mm
width 60 mm
cover: width 52 mm
overall: height 104 mm

type:: box sextant and instrument case

credit:: Admiralty Hydrographic Department

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Parts

Pocket Box Sextant, 1830-1869

Surveyor's pocket box sextant, 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.