Compass dial for latitudes 40°-60° North. Round brass fob sundial with a suspension ring for attachment to a fob chain. The brass lid opens to reveal a white metal dial-plate set over a centrally set compass. There are two concentric hour scales marked for 50° and 40° respectively, numbered clockwise 6-12,1-6. The centre of the plate is open to reveal the compass. The brass gnomon is shaped, hinged and folds flat when not in use. It has a white metal bird index whose beak indicates the latitude; the latitude scale on the West side of the gnomon is divided 40°-[60°].

The compass is made of white metal. The degree scale is divided clockwise 0°-[360°]. It has eight points, marked by French initials. The needle is blued at its North end and is surmounted by a cylindrical brass pivot. A cracked glass plate covers all. There is a milled wheel in the rim of the compass for locking the needle in position. Unusually for a compass dial, this one is adjustable for more than one latitude. The use of the bird index is reminiscent of the Butterfield dials of the previous century. There are also similarities between this instrument and AST0151.

For more information regarding this dial please refer to the OUP & NMM catalogue, 'Sundials at Greenwich'.