Description

This disc-shaped pocket sundial is made of white metal. It is engraved on both sides, one of which is equipped with a fold-down brass gnomon, while the other has a movable gilt-copper index with a suspension ring.

 The face forming sundial is engraved with several vertical hour lines ranging from 2 to 11 o’clock (‘Orientale’ = Eastern) in the upper part and from 1 to 10 o’clock in the lower part (‘Occidentale’ = Western). These lines intersect the lines of the sun’s declination, which are marked with the signs of the zodiac at their left ends. The central line corresponds to the spring and autumn equinoxes, while the two outer lines correspond to the summer and winter solstices. A wave pattern is engraved on either side of these lines. The fold-down brass gnomon is positioned at the 6 o’clock line.

The other side is engraved with six concentric scales. The one on the outer edge corresponds to latitudes and is graduated 90 – 0 – 90 degrees, marked in increments of 10 and divided into degrees. The other five scales correspond to a list of cities with their respective latitudes. A movable index, made of gild-copper and engraved with a stylised palm tree design, is topped by a brass suspension ring and allows the dial to be oriented to the latitude of the location.

Although unsigned, this sundial can be unambiguously attributed to Johann Martin of Augsburg based on the calligraphy and engravings. Several of his works are preserved in public collections.

Johann Martin (1642-1721) was a German sundial maker from Augsburg. He invented the crescent-shaped gnomon sundial. He was the step-brother of Johann Willebrand and the step-uncle of Johann Martin Willebrand, see « Alt-Augsburger Kompassmacher », Bobinger, 1966, pp. 154-156.

This extremely rare sundial is in a very good condition and fully functional.