Augsburg dial for latitudes 0°-90° North. Standard dial (see related terms) except for the following details:-

The dial-plate and compass are silver. The compass has a degree scale and the cardinal points have full Latin names. Within the degree circle there is a rotatable disc with a centrally engraved flower and an arrow engraved to show the magnetic variation; a pinhole at the end of the arrow allows the disc to be rotated from the back of the compass. The silver latitude arc is divided [0°]-90°. A silver hour band, hinged to the dial-plate, is set inside a gilt-brass ring and the brass gnomon is spring-loaded. A plumb-bob support is hinged to the South side of the dial-plate, which is supported by three silver-gilt legs. On the reverse side it is signed 'Johann Willebrand in Augspurg 48'. On a disc in the lid of the case, a table of latitudes for a great number of towns and cities in Europe is engraved, including 'Barcellona 41', 'Berlin 52' and 'Stockholm 60'.

This piece is similar to those by Johann Martin, but it includes a rotatable disc in the base of the compass that allows the pointer for the magnetic variation to be moved to take into account the way in which the variation changes with time and place. A similar instrument was in the Greppin Collection sold in 1975, although that one sets the latitude by means of a cam mechanism. Several Willebrand Augsburg dials are included in the Billmeir Collection in the MHS, Oxford.

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