Universal equinoctial dial for latitudes 0°-90° North. Pivoted on a semicircular arc, the hour-circle is hinged to the North side of the base-plate and numbered clockwise I-XII, I-XI, 12. To allow the latitude arc to pass through the hour-circle, there is a hole against the '12', and the East-West diameter is spanned by a pivoted strut, which supports the rod gnomon. The latitude arc is attached to the hinge of the hour-circle support and has a degree scale divided [0°]-90°.

The compass is set on the obverse side of the base-plate. Its degree scale is divided clockwise [0°]-360°, and it has an eight-point rose (although the remaining 24 points are also marked) with the points named in French and a fleur-de-lys for North. An arrow indicates magnetic variation at 22° West of North. The needle has an open ring for North and is surmounted by a brass pyramidal pivot. A glass plate covers all. On the reverse side of the base-plate is a table of latitudes comprising towns and cities in Western Europe.

This dial is unusual in that the latitude arc passes through the meridian line of the hour ring, rather than being hinged to the plate at the West side. While the date of the dial would indicate a magnetic variation of about 15° West of North, the mark actually given (22° West of North) is the value reached in the second half of the 18th century. Hence, the compass may be a later addition to the instrument. It is signed 'Le febvre AParis'.

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