Compass dial for latitude 50° north. This is a round brass fob sundial with a suspension ring for attachment to a fob chain. The dial-plate (which is off-centre) is supported by two crossed radial gilt-copper struts, with an open ring at one end. The plate is printed paper with an hour scale numbered clockwise 6-12, 1-6 and has hour-lines that radiate from the base of the style. The gnomon is shaped and made of copper. The compass is of printed card. It has eight points marked by French initials and North is further indicated by a fleur-de-lys. There is a magnetic variation scale, divided anticlockwise [0°]-30°, and a double-headed arrow marks the magnetic variation at 21° West of North. The needle is blued at its North end. On the reverse side, the equation of time is laid out in concentric circles; it is covered by convex glass.

The inclusion of the equation of time on the back of a dial as small as this is unusual. The instrument was almost certainly not of a high enough accuracy for the adjustment to mean time to be useful. It is signed 'H. SARTON A LIEGE'.

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