Universal equinoctial dial for latitudes 0°-90° North. The compass is set into the dial-plate and is surrounded by detailed vignettes depicting Arithmetic, Geometry, Astronomy and Geography, anticlockwise from bottom left. The compass has 16 points marked by French initials. To the West of the compass, the latitude arc is hinged to the dial-plate. It is engraved ‘Butterfield AParis’.

The hour ring is hinged to the dial-plate on the Northern edge of the compass. A strut across the ring’s East-West diameter supports the rod gnomon. On the reverse of the dial-plate is a Rojas projection surrounded by engraved flowers, leaves and ribbons. The remainder of this circle is occupied with part of a table of latitudes for places in southern Europe. The disc has a pointer on one edge, which is marked ‘1616’. Pivoted at the centre of the disc are two index arms set at right angles. One is marked ‘inDex’ and has two pinhole sights set in square mounts. The other, signed ‘A Ferrier’, carries a hinged arm which is a plumb line and which has an oval weight with a depiction of a monkey gripping the rope plumb line.

The sides of the dial are engraved with the latitudes of various towns in Europe, including London, Paris and Constantinople. The latitudes listed are highly inaccurate for the southern Mediterranean towns, with errors of up to 3°. The dial can be carried by a silver suspension loop fixed to one side of the instrument.

This dial carries much of Ferrier’s fine decorative engraving. The instrument was modified by Michael Butterfield around 1700, the parts added being the compass, equinoctial dial and probably the table of latitudes. Clear similarities can be seen between this and Butterfield’s Augsburg dials (see AST0524).

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