An early sextant by the famous London maker Jesse Ramsden who worked from 1762-1800.
Constructed of straight bar brass frame, 17.5" radius and 135 degree arc. 17" high. Signed RAMSDEN. LONDON to the middle horizontal bar. Full length sighting tube missing the lenses.
Six shades, index mirror with maskelyne flap, secondary mirror on rear mounted adjusting lever, wooden handle and pin feet.
Weighs 2.4kg.
He was a mathematician, astronomical and scientific instrument maker. His reputation was built on the engraving and design of dividing engines which allowed high accuracy measurements of angles and lengths in instruments.  He spent four years from 1958 as a mathematical instrument maker apprentice and then set up his own business. The quality and accuracy of his instruments established his reputation as the most able instrument maker in Europe for the next forty years until his death in 1800.  Ramsden was elected to the Royal Society in 1786 and to the Royal Society of Edinburgh around 1798. The Copley Medal of the Royal Society was bestowed upon him in 1795 for his 'various inventions and improvements in philosophical instruments.
Ramsden Rock in Antarctica is named after Jesse Ramsden.