Portable horizontal dial for latitude 49° North. The dial-plate is oval shaped. On the obverse side is an hour scale depicted on a scroll. The dial is marked 'pour 49 deg' (for 49 degrees) and features a centrally placed rose decoration. The gnomon is hinged, shaped, decorated with leaves on a hatched background and folds flat when not in use. The compass, which is incorrectly oriented, has a North-South line with 'N' for North. It has a blued needle with an open circle for North, and is surmounted by a brass pyramidal pivot. There is a glass plate over all.

The dial is supported by the compass bowl, which is decorated by an acanthus design, and two turned silver legs. The case is oval shaped and made of black fishskin, with green velvet lining and a brass push-button clasp. The dial is signed 'Roch Blondeau AParis 1670' and was made at, or shortly before, the time Blondeau began to produce what were among the first so-called Butterfield dials. It is, however, similar in style to them. Another fixed latitude dial by Blondeau is in the MHS, Oxford (new inventory no. 50646).

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