An important navigation instrument, the first sectors are recorded as far back as the late 16th Century. The instrument is used to make mathematical solutions in conjunction with a pair of dividers, using trigonometric principles.

This example is in fine condition, with the maker’s engraved name of J. Watkins of London prominent. Jeremiah Watkins is listed as having a scientific instrument maker in the Charing Cross area of London alongside of William Watkins from 1790 to 1817, and as being in the service to the Duke of Clarence.