Universal equinoctial dial for latitudes 10°-90° North. The obverse and reverse sides of the dial-plate both contain tables of latitude for towns and cities in Europe. Hinged to the North side of the dial-plate is an hour-circle. The gnomon support plate is riveted to the top of the hour-circle and decorated with floral engraving while the gnomon itself is a bar hinged to the support plate to be set perpendicular to the hour-plate. The latitude arc is hinged to the West side of the dial-plate. It carries a degree scale on its outer side and an adjustable clamp with a butterfly screw, which supports the hour-circle. The plumb bob is a simple detachable support mounted in a holder attached to the compass. It is pierced for a green string plumb line (which is broken) and carries a conical bob.

The compass is set on a plate at the opposite end from the hour-circle hinge. The cardinal points are named in Italian and the magnetic variation is marked by an arrow at 8° West of North. On the reverse side, the dial is signed 'Iacobus Lusuerg Faciebat Romoe 1688'.

A dial of very similar form and with the same signature inscription is in the Whipple Museum of Science (accession no. Wh: 0323). Despite being made in Italy, the instruments show a strong French influence and there are almost as many French towns as Italian listed in the table of latitudes.

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