Magnetic dial and thermometer for latitude 51° North, set in a leather case. The dial-plate is of ivory and the mercury-in-glass thermometer is bent into a circle around the sundial. The thermometer has scales for Réaumur (marked Reaur) and Fahrenheit (marked Fahrt). 'Freezing', 'Summer heat' and 'Blood heat' are marked along the scale. The centre of the plate is occupied by a horizontal dial on a compass card (the magnetic bar on the reverse side is missing). It has a red border, 32 compass points are marked, seven by English initials, and North is marked by a fleur-de-lys. Within this is an hour ring and a simple brass gnomon.

The case is round, made of red leather and has silk lining in the lid. Two brass hook fasteners (one missing) and a brass hinge clasp it together. The addition of a thermometer to a dial-plate is unusual. This one is calibrated for Fahrenheit and Reaumur, the latter being a temperature scale in which the freezing point of water is 0° and the boiling point is 80°. The dial itself is very small and would only have been accurate for the date that it was made since the card was made for a particular magnetic variation. On the dial-plate it is signed 'T. Staight London'. Another, slightly larger version is in the MHS, Oxford (new inventory no. 37175).

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