Three-ring universal equinoctial ring dial for latitudes 0°-90° North. Standard dial (see related terms) except for the following details:-

The dial is for northern latitudes only. The suspension bracket carries a vernier scale divided 60'-0'-60' to allow the setting of the latitude to an accuracy of 10' of an arc. The suspension ring is missing and the reverse side of the meridian ring is blank. The equinoctial ring has two sections sliding against each other to allow for a finer calibration and the hour markers on its obverse side are enamelled in black. The inner section carries a vernier scale for minutes to allow the reading of time to an accuracy of one minute. The reverse is plain apart from the signature: 'Lordelle AParis a la sphere'. The declination ring is only engraved on its inner rim with a declination scale and the alidade is missing.

The dial has a black fishskin circular case with red velvet lining and two brass hook fasteners. Inscribed in gold on the lid are the words, 'ANNEAU ASTRONOMIQUE MERIDIEN DE MR. DE LA CONDAMINE EN 1735'. The declination ring on this dial is attached to the equinoctial ring rather than the meridian ring. The movement of the declination ring also moves the inner section of the equinoctial ring. M. de la Condamine seems to have been the first owner of this instrument, since the date on the case corresponds with the date at which Lordelle was working.

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