Very rare 18th century ebony and ivory octant Georges II – Louis XV period, ca. 1750 Radius : 17,8 in Octant ebony and ivory – Signed by the French dealer Decard Bordeaux, retaining the name of the manufacturer * GREGORY fecit * Henry Gregory, optician and manufacturer of measuring instruments in London between 1744 and 1782. Same octant is presented in the collections of the Independence Seaport Museum in Philadelphia – that belonged to John Barry, founder…