The Private Collection of Theodor Beyer

Hotel Baur Au Lac, Zurich, Nov 16, 2003

LOT 7

Cross-Beat Escapement. Jerg Ernst, Augsburg, first quarter of the 17th century. Fine and very rare oval smoked crystal, gilt silver mounted, large octagonal pre-balance spring pendant watch with cross-beat escapement.

CHF 20,000 - 30,000

EUR 13,000 - 20,000 / USD 15,000 - 22,000

Sold: CHF 32,200

C. Two-body, hinged, back and band formed from two single pieces of faceted smoked crystal, mask pendant and finial. D. Gilt silver, champlevé radial Roman numerals, inner quarter divisions, champlevé center with polychrome flowers and a bird, the whole on gilt pierced and engraved domed plate. Steel tulip hands. M. 51 x 41 mm, oval, full plate, baluster pillars, fusee and gut, short train, cross-beat verge escapement, two foliots geared together and terminated with silver winged cherub masks, small irregular cock with high neck, striking works removed, elaborate mainspring set-up ratchet click. Signed on the back plate.Dim. 81 x 50 mm.


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Grading System
Grade: AAA

Excellent
Case: 3-14-22-38

Good

Damaged

Later original

Slightly rubbed
Movement: 3-12-13*

Good

Worn

Slightly damaged

Overhaul recommended, at buyer's expense
Dial: 3-24-05

Good

Slightly chipped

HANDS Luminous material reapplied

Notes

Provenance: Belin Collection. Georg (Jerg) Ernst, Augsburg. Became Free 28.12.1621, died after 1634. Among his known works are: a table clock in the Kunsthistorisches Museum in Vienna, No. 322; an octagonal rock crystal pendant watch, circa 1630 (formerly in the Slg. Pleissner collection); a four-sided table clock, circa 1600/1650. Cross-Beat Escapement. The verge escapement was not sufficiently accurate to fill the needs of scientists and astronomers, especially before the invention of the balance spring. This was why Jost Bürgi, a celebrated clockmaker of Wilhelm IV of Hesse, invented a new escapement around 1580. It had less recoil and was considerably more accurate. Bürgi had become so famous that in 1603 the Emperor Rudolf II asked Landgrave Moritz, the successor of Wilhelm IV, to allow Bürgi to come to the imperial court. It was in Rudolf's court, that Bürgi's clocks with cross-beat escapement helped Tycho Brahe and Johannes Kepler to make their astronomical discoveries. These were the most accurate timekeepers in existence until the invention of the pendulum. These types of clocks, copied by Augsburg masters such as Hans Buschmann, Matthäus Hallaicher, Nikolaus Planckh and others, came to be known as "Prague clocks', as the imperial court, before moving to Vienna in 1620, was in Prague. They are extremely rare and very seldom apear on the market. They were so extraordinary that as late as 1734, Jean-Baptiste Dutertre of Paris presented to the French Academy of Sciences a double pendulum clock based on the cross-beat escapement.