Universal equinoctial dial for latitudes 0°-90° North. The base-plate is supported by four brass levelling screws. Hinged to its North side is an hour-circle segment, which is divided clockwise on its inner rim and numbered III-XII, I-IX. A bracket is screwed onto the East side, admitting the latitude arc, and which has a screw that can be tightened to hold the hour-circle at the required angle. A pivoted rod across the East-West diameter of the ring supports the rod gnomon. The plumb bob support is hinged to the South side of the base-plate, is decorated on the outside and is open in the centre to admit the brass plumb bob. The compass displays an eight-point rose with a fleur-de-lys for North and the intermediate points are marked by arrows and initials. A raised degree circle is divided 0°-90°-0°-90°-0°, and a blued needle marked 'N' and 'Z' is surmounted by a brass pyramidal pivot. A glass plate covers all.

This instrument is possibly derived from a particular style of English universal equinoctial dial, first invented towards the end of the 18th century, which was popular during the 19th century. It is more elaborately decorated than those dials, however, and has very ornate engraving on the plumb bob in particular.

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