Pocket sextant

The sextant consists of circular polished brass plates with a lid that when fitted on the back of the instrument serves as the handle. The index arm is moved by a milled knob on the upper plate. The sextant has one red index shade which is moved by a lever. There are no horizon shades. The index glass is non–adjustable whereas the horizon glass is moved by a milled knob shipped in the upper plate.

Attached to the sextant is a single lens magnifier on a 45mm swivelling arm. It has a sliding shutter with choice of a pinhole or a red shade. The two screws to hold the upper plate are missing. The sextant is contained in a rectangular wooden box, which also contains an artificial glass horizon (NAV0019) and a pocket compass (NAV0466).

The instrument has a polished brass limb with an inlaid silver scale from -5° to 145° by 30 arcminutes, measuring to 129° (the digits are read from the pivot). The sextant has a silver vernier measuring to 1 arcminute, with zero at the left.

The sextant belonged to Edward Newell Harrison, clerk of HMS ‘Assistance’, who went to the Arctic in 1850-51, in search for Sir John Franklin, and died in the West Indies before 1855.