The name octant derives from the Latin octans meaning eighth part of a circle, referring to the angle of 45 degrees between the arms of the frame. The ivory scale is divided into 90 degrees, or one fourth of a circle. John Hadley (1682-1744) described an instrument of this sort to the Royal Society of London in 1731 and obtained a British patent in 1734. Accordingly, octants are sometimes known as Hadley quadrants.
This is a fine, large mahogany-framed octant with ivory scales and a decoratively engraved 16 inch arm. The arm's engraving depicts a swan among reeds with flowers and foliage.The instrument is in immaculate original condition overall. The brass and ivory have been lightly cleaned and the frame has been cleaned and waxed. It includes a custom-made mahogany and brass display stand.
This octant is signed Josh. Gaitskill, Wappin (Wapping), London. Joseph M. Gaitskill, NIM (Nautical Instrument Maker) practiced at two Wapping High Street addresses, 123 and 129, between 1793 and 1823. Wapping is just east of Tower Hill and the concentration of 18th-19th century instrument makers.
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