This dial is in the form of a three dimensional heart. Both external sides are finely decorated with strapwork.
The inner part of the lid is blank. The inner part of the box has at the centre a compass with magnetic deviation marked. Around the compass, in the shape of concentric hearts, is strapwork decoration, then the hour lines of the string gnomon dial, indicating common hours from VI to XII to VI, and strapwork decoration on the remaining surface. The string gnomon is held by a hinged folding support. It is possible that it is a later restoration, as is the whole of the compass.
The hollow space below the dial-plate is a powder flask. There are also two small rings for suspension, one of which is broken.
The dial is was formerly in the Bernal Collection and is described in F. A. B. Ward, A Catalogue of European Scientific Instruments in the Department of Medieval and Later Antiquities of the British Museum (London, 1981), p. 22, no.11. It is similar to an example illustrated by A. Rohde, Die Geschichte der Wissenschaftlichen Instrumente, (Leipzig, 1923) p.13, figs. 6 and 7.