Universal equinoctial ring dial for all latitudes. Standard dial (see related terms) except for the following details:-

There is an hour scale on the obverse side and on the inner-rim of the equinoctial ring. There is a date scale, with 'N' and 'S' marked at each end of the scale, an incomplete declination scale and a zodiac scale. The equinoxes are marked at 23 March and 6 September (the '0' of the declination scale is correct, so the date scale must have been incorrectly drawn for the second half of the year). The bridge has rectangular ends and the gnomon has glass in the pinhole.
The main dial is typical of an early 18th century English instrument. The bridge, however, is almost certainly a replacement since it lacks the standard sloping shoulders and the autumnal equinox is incorrect.

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