An azimuth compass with a brass bowl, mounted in gimbals in a wooden box. It is fitted with open brass sights and a shadow pin. The card has a brass rim and is graduated to quarter points with each half-point decorated with fleur-de-lys. The North and East points are also decorated. The card has a quadrantal degree scale around the outer edge, graduated from 0 at the East and West points to 90 at North and South. This is the reverse of the usual arrangement and was probably to facilitate the taking of amplitudes.

The compass is similar to those designed by Gowin Knight for taking bearings of terrestrial objects and of the Sun. It incorporates Knight's earlier improvements and is fitted with open sights and a shadow pin attachment. A Knight azimuth compass by G. Adams (and signed on the reverse of the card J.H. de Magalhaens 636) that is said to have been used is in the Mitchell Library, Sydney, Australia. Knight's compasses were made by George Adams, but certified and numbered by Knight. After his death in 1772, certification was carried out by J.H. de Magalhaens. Adams continued making the compasses until 1782, when it is believed Rust and Eyre took over their manufacture. NAV0447 is a similar compass by Adams with the card signed by Knight.