Portable horizontal dial for latitude 45° North. This is a folding dial with two halves hinged together. The gnomon is self-erecting when the dial is opened. Hours are marked round the edge and it is engraved with curlicue decoration. There is a circular hole in one corner of the plate (perhaps for a compass) and a five-pointed star at the end of a line extending from the hole (magnetic North perhaps). The hinged gnomon is triangular in shape and is apparently for latitude 45°. 'PATENT BIRMINGHAM 1875' is stamped either side of the gnomon.

This instrument is similar to dials both in the British Museum (registration no. 1893,10-9.12) and in the Whipple Museum (accession nos. Wh: 0858 and Wh: 1201). However, unlike these three, it has very little decoration, the hour-lines are inaccurately drawn and it seems to be unfinished. None of the instruments contain a compass and if one had been present in the hole in the south-east corner of the plate it would be impossible to close the dial. Bryden (1988) remarks that no British patent has been found for this instrument, and the unusual latitude for an English instrument might be due to the makers simply producing an isosceles triangle for the gnomon without having understood the theory of sundials. Thus, the instrument may be no more than a toy.

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