Brass triangle-pattern frame sextant.

Black-lacquered brass sextant, triangle-pattern frame, with polished limb, wooden handle and square fitted, mahogany box, by John Crichton, London, 1880-1890. Consists of 125° inlaid silver scale of 7 1/2-inch radius (-5° to 145°) with10' divisions, silver vernier reading to 10", four shades (all green), three horizon shades (all green) and scale magnifier on a 70 mm swivelling arm. Fitted with threaded telescope bracket for two telescopes (84 mm) erect image, (185 mm) inverted image, four cross-wires and two extra draw tubes (80 mm) inverted image, two parallel cross-wires and sight tube (81 mm).