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Astronomical clock by Johann Sayller at the Landesmuseum...
History & Masterpieces

Astronomical clock by Johann Sayller at the Landesmuseum Wurttemberg

Monday, 03 September 2012
By Dr Irmgard Müsch
Dr Irmgard Müsch

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8 min read

The costly material from which it is made, the elegance of its design, and its technical sophistication make the silver table clock by Johann Sayller (1597–1668) one of the master pieces in the collection of about 700 clocks and watches in the Württemberg Landesmuseum.

Many of these clocks and watches have been purchased by the Landesgewerbemuseum with the aim of promoting local industry through the presentation of objects of national and international origin that are models of their kind in terms of technical accomplishment and craftsmanship. To this end, clocks from the Late Gothic Period to the 19th century have been acquired, so that, by means of important examples, the collection provides an overview of international clockmaking from its beginnings right up to the 19th century. The museum now focuses on the acquisition of clocks made by the master clockmakers of Württemberg, including Sayller and in particular Philipp Matthäus Hahn.

External Features

The clock is built in the classic tower-shaped clock form. The body of the clock, which is square at its base, is borne by four cast feet with lions gazing out from a fantastical structure of fish bodies and dragons’ wings terminating in volute scrolls. The case, with its high plain rectangular sides and cast corner figures in the form of winged female herms, rests on a solid base of imposing outlines. The transition to the superstructure is formed by a sawn-out arcade of solid cornerstones bearing obelisks. Behind this, rises the octagonal bell case with its open-work walls decorated with symmetrically engraved foliage. On the flat upper side of the bell case is a rotating horizontal silver plate showing the age of the moon (2-29½) and the phases of the moon. It is topped by a floating silver ball representing the moon. Above, in the form of a baldachin and supported by eight cast volute scrolls, is the onion-dome roof with its crowning skeletonised obelisks.

The front dial is decorated with a battle scene against the backdrop of a castle. An engraved and gilded hours hand points to the hours of the small clock on the inner chapter ring. The minutes hand, which is made of blued iron, makes one rotation every two hours and shows the minutes and the quarter-hours (the Roman figures I-IIII twice), on the engraved dial. The movement can be wound up with the square arbor underneath the dial.

The back comprises one large and two smaller dials. The smaller dial on the left shows the days of the week and their reigning planets with Latin inscriptions. The right-hand small dial shows the hours struck by means of a gilded hours hand, and has an engraved representation of Mucius Scaevola, the Roman hero.

The long blued hand on the outer ring of the large dial indicates the date of the day on a 5 to 5 division, while a richly skeletonised and engraved gilded hand indicates the month. The back end of the gilded hand, decorated with a sun, shows the position of the sun in the zodiac from form 10 to 20 days on the inner ring. The central field is decorated with lambrequins and vines.

On the right side of the case is a small regulating dial with the figures 1-8 and 10 it bears the signature “Johann Sayller fecit Vlm”.

Johann Sayller (1597–1668), Tower-shaped silver astronomical table clock with three-month power reserve, Ulm, circa 1630 (detail) © Photos : Landesmuseum Württemberg / H. Zwietasch
Internal Features

The plates and pillars of as well as the impressive and the clearly arranged movement are are made of gilded brass. The wheels are mostly made of brass and the arbors are made of iron. The lower plate also bears the signature “Johann Sayller fecit Vlm”.

The feature that is most immediately striking when one looks at the movement (Fig. 2) is an unusually large fusee, beneath which, in the base of the case, an equally remarkable barrel (diameter 18 cm, height 9 cm) has been positioned. The equally large spring and its powerful driving force provide a power reserve of three months (an unusually long period for the time).

A strong chain connects the barrel and the fusee. To wind the clock up, the fusee is turned by means of a square arbor. The chain then fills all the helical threads of the fusee. As the chain is wound up onto the fusee, it is unwound from the barrel. To this end, the barrel is also armed and thus the spring inside it is wound up. The variation of the circumference of the fusee balances the spring tension as it slackens over the three-month period, guaranteeing a constant driving force.

Interestingly, the force of the spring does not (as might be expected) directly drive the display gear-train via the fusee. Instead, the energy is transferred to the striking mechanism (with fly) and – controlled by the striking mechanism – to a second cylindrical barrel behind the front face. If the striking mechanism is triggered, the fusee moves slightly and at the same time winds up the much smaller spring of the actual movement via its large geared rim by means of a pinion. Since this spring is thus constantly being rewound, although its tension is at a maximum after the 12 o’clock chime and at a minimum after the 6 o’clock chime, it nevertheless achieves its former tension after a further six hours, so that the next 12-hour cycle can be repeated under the same conditions.

The striking mechanism, and hence the transfer of energy to the small spring, are controlled by an escapement positioned under the dome, consisting of a balance wheel and a pallet-fork, the two ends of which alternately engage with a geared escape wheel. The “anchor escapement” was first developed in England in 1715, which means that the highly valuable Sayller clock was brought up to the latest technical standard about 100 years after it was created.

The clockmakers

Born in 1597 in the Bavarian town of Angelberg, Johann Sayller settled in Ulm in 1617 and worked as a clockmaker’s journeyman. In 1624, having successfully passed his master clockmaker’s examination, he became citizen of Ulm. In 1646, the clockmakers of Ulm made him their guild master. He died in Ulm in 1668.

Before the middle of the century, i.e. before the pendulum entered into clockmaking technology, Sayller was experimenting with various technical innovations that were intended to achieve greater accuracy. For example, he also created a rolling ball clock. This clock is also in the Landesmuseum, together with another tabernacle clock, two horizontal table clocks and two pocket-watches.

The clockmaker worked with various goldsmiths. The goldsmith’s craft as practised in Ulm had established a considerable reputation from the late Middle Ages onwards, although never achieving the same recognition as in Augsburg or Nuremberg. The goldsmiths worked predominantly for the upper class in Ulm, producing costly prayer book bindings, goblets for christening presents and in particular table decorations and drinking vessels for various festivities and celebrations. The case of the tower-shaped astronomical clock has been stamped twice with the control stamp of the City of Ulm, and also bears the master’s mark of the Ulm goldsmith Hans Jerg Merckle the Elder (1588–1634).

The acquisition of the master craftsman certificate by Sayller, together with the date of Merckle’s death, provide the key dates for the creation of the clock, indicating that it must have been made between 1626 and 1634. This aesthetically delightful and technically complex clock can be viewed from 25 May 2012 onwards in the newly designed presentation of Württemberg history “Legendäre MeisterWerke – Kulturgeschichten aus Württemberg” [legendary masterpieces – objects from Württemberg’s cultural history” in the Landesmuseum Württemberg in Stuttgart.

Reference: Volker Himmelein, Uhren des 16. und 17. Jahrhunderts [Clocks of the 16th and 17th centuries], Württembergisches Landesmuseum, Stuttgart 1973, No. 42

The ancient art of time measurement
The art of time measurement is one of the great advances of humankind. This centuries-old heritage is rightfully conserved in numerous, though often little-known, museums. So as to bring these riches to life, HH Magazine presents some of the most exceptional pieces, chosen for their technical significance, historical importance, or for their beauty. This regular feature trains the spotlight on a timepiece which has been chosen and described by the curator of the horological collection of one of the approximately two hundred public or private museums which conserve clocks and watches in their collections.

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