German pocket chronometer with regulator dial Circa 1790

Silver open faced pocket watch by Jacob Auch
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An important, heavy German pocket chronometer with regulator dial and pivoted detent escapement, 1790. Made by Jacob Auch, the most talented pupil of clergyman and famous precision engineer and watchmaker Phillip Matthaeus Hahn. This timepiece features a polished silver case with a reeded band. The enamel dial displays radial Roman hours at 12 o’clock, auxiliary seconds, and blued spade hands. The movement is a full plate type, keywind, frosted, and gilt, with rounded movement pillars, a pivoted detent escapement, a four-arm bimetallic chronometer balance with two screws and two trapezoid weights, a pierced balance cock, and a sapphire endstone on the balance.
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Diameter: 65 mm
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Weight: 213 g
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Signed: Jacob Auch, Hofmechanicus in Weimar
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Provenance Gerd Ahrens, Collection Gerd Ahrens
This watch is probably the earliest watch ever built in Germany with a chronometer escapement. Very likely, it is also one of the first ones to be made in Weimar. Later, watches by Jacob Auch were signed by Seeberg, where the observatory was. This is quite obviously a very early piece – a basic construction, and re-assembling the movement after cleaning is difficult. The escapement shows certain similarities to those of Ferdinand Berthoud. Jacob Auch began his apprenticeship in the workshop of Philipp Matthaeus Hahn in Echterdingen. From 1787 until 1798, he had his small workshop in Vaihingen an der Enz and worked for the Institute of Physics in Karlsruhe. As court mechanic for the Duke of Weimar, he worked mainly for the new Seeberg Observatory from 1798. The renowned astronomer Baron Franz Xaver von Zach headed the observatory until 1806 and was one of Jacob Auch’s most important customers. Auch supplied numerous watches and instruments for the observatory, which was, at the time, the most modern in Europe. His work was always measured against the quality of English chronometer makers such as Josiah Emery and Thomas Mudge. Auch also created important astronomer’s pocket watches in the style of his master, Philipp Matthaeus Hahn, with dials on both sides; they showed the traditional watch face on one side and planetaria on the other. One of Auch’s most famous customers was Johann Wolfgang von Goethe.