Butterfield dial for latitudes 40°-55° North. Standard three-scale dial (see related terms) except for the following details:-

It has an oval plate. The three scales are marked for 55°, 51° and 45°. The central section is engraved with the arms of the Duke of Marlborough, which includes a griffin, the cross of St George, the motto: 'HONI SOlT QUI MAL Y PENSE' (Shame on him who thinks this evil) and a family motto: 'FIEL PERO DES DECHADO' (Faithful but unfortunate). The compass has cardinal points marked by English initials and the North point is offset 7° West of North to allow for magnetic variation. The gnomon, engraved with acanthus and a beast's head, is adjustable for latitudes 40°-55° and there is a latitude scale on both sides. The griffin index has a forked tongue to mark the latitude and carries the cross of St. George on a collar around its neck. On the reverse is also a table of latitudes for European towns and cities, headed 'Names of Places', in two columns. It is signed 'I:Rowley LONDINI FECIT.'.

This piece was made by the London instrument maker John Rowley. He was one of the best instrument makers of the 18th century, and these dials are fine examples of his work. The dial, which has a black leather case, was made for John Churchill, the first Duke of Marlborough, hence his coat of arms on the dial. The place names on the back are connected to Marlborough's campaign in the Low Countries during the war of the Spanish Succession.

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