Grand Complication No. 42500 by A. Lange & Söhne 

In 2001, a dramatic incident changed the working life of Jan Sliva, head of the in-house studio for historic Lange pocket watches. A visitor of the manufactory had handed him an old pocket watch and asked for an appraisal. It was clear from the very first moment that this timepiece was an extraordinary one. It was particularly large and heavy, and its case was engraved with an intricate motif designed by Professor Graff.

But when Jan Sliva opened the artistically decorated caseback, what he saw sent shivers down his spine. He discovered a movement that at best could be called a “scrap heap”. All parts were grimy, many were rusted, some were missing altogether, others were broken or so heavily corroded that their original shape could merely be surmised. Only the consummately assembled eight-part enamel dial was, surprisingly, almost in mint condition.

It didn’t take long for Jan Sliva to spot the serial number on a bridge: “42500”. According to the journals, it identified a unique treasure with probably the most complicated, rare, and historically significant calibre that had ever left the A. Lange & Söhne manufactory – and it was the only one of its kind. Pocket watch No. 42500 had been sold to a resident of Vienna for 5,600 marks in 1902. At that time, the sum was equivalent to the price of a stately house.

An inestimably precious junkyard

“This watch,” Jan Sliva explains today, “unites a host of fascinating complications. It incorporates a chiming mechanism with a grand strike and a small strike, a minute repeater, a split-seconds chronograph with a minute counter and flying seconds (seconde foudroyante), as well as a perpetual calendar with a moon-phase display. Its nickel-plated German silver movement in 1A quality consists of an incredible 833 parts. Together with the case, it weighs nearly 300 grams.” It was a watch of inestimable historic value and its restoration would justify any conceivable amount of effort. That much was clear to Jan Sliva at first sight. 

The very poor condition of the watch raised a fundamental question: how should such a rare and complex masterpiece be dealt with? Should the watch be left in its presentcondition and exhibited “in the raw”? For Jan Sliva and his colleagues, this was not really an option. Instead, they decided to study and document the functions and interactions of the individual components on the basis of what was left and to fully restore the functionality of all the mechanisms. “This is the only chance we had,” says the master watchmaker, “to preserve the ingenuity of our fathers and forefathers for coming generations. What good is a heap of rust, however authentic it might be, if no one knows what it once looked like and how it worked?”

The secrets of the 833 parts

Thus, the declared objective was to conserve as much of the original substance as possible and then to reinstate the function and beauty of the venerable movement. For starters, this meant heavy-duty research, because the watch harboured many secrets that would have to be arduously deciphered. It contained a number of parts whose function eluded even the experts. There were components of such intricacy that no one could imagine how they might have been crafted, and even advanced CAD software failed to provide clues. Other parts which would have to be replaced were so deteriorated that their original geometry could no longer be conjectured. Every layer that Jan Sliva exposed raised scores of new questions – for instance how to craft an unusual type of gong for which no specifications existed. In some cases, months went by before a satisfactory solution to a problem could be found. Sometimes, the first try was successful. But the watch has also kept a few secrets to this very day.

Magnificent comeback for a complicated star

In the end, it took until the year 2009 to restore pocket watch No. 42500 to its former splendour. At the SIHH 2010 in Geneva, it will be on public display for the first time. It is a breathtaking remnant of tradition that has come alive and a bridge that connects the ingenuity of the Lange watchmaking dynasty with the virtuosity of the current generation of watchmakers. Indeed, it is a monument of horological expertise and human passion. For Jan Sliva, however, this watch is something like the highlight of his horological career. “After this, I can’t imagine what might still lie ahead,” he says. “Only very, very few people get a chance during their lifetime to restore such a treasure.” No. 42500 is his lifework, so to speak.

With its ZERO-RESTART function, an innovative seconds hand resetting mechanism, the limited-edition RICHARD LANGE "Referenzuhr” enriches the line of observation watches dedicated entirely to precise time measurement.

Just like its famous namesake, the RICHARD LANGE watch family is fully devoted to the scientific facets of horology with a focus on the utmost degree of precision. It has its origins in the understanding that the accuracy of a timepiece reflects the competence of the master. At A. Lange & Söhne, this insight dates back far into the 19th century. With its resettable subsidiary seconds, the RICHARD LANGE “Referenzuhr” continues this tradition. The actuation of a push piece above the crown causes its seconds hand to jump to zero and wait there as long as the push piece is depressed. During that time, a vertical disc clutch assures that the ongoing measurement of time is not interrupted – the movement keeps running. When the push piece is released, the seconds hand restarts instantaneously.

This ZERO-RESTART function is very useful for stopping events of short durations. It is also ideal for synchronising watches and clocks at different locations: the actuation of the push piece synchronises the seconds hand of the instrument with that of a reference clock exactly when its hand passes the 60-seconds mark (“zero”). This action “stores” the time of the reference clock and allows it to be transferred to other timekeeping instruments. The RICHARD LANGE “Referenzuhr” pays homage to a stronghold of time measurement that played in important role in 19th-century Dresden: the timekeeping service of the Mathematics and Physics Salon. As the “keeper of time”, this scientific institution was responsible for precisely determining the local time and making it available to the city’s population. So in a sense, it was the predecessor of present-day atomic clocks and time signal transmitters. But in those days, the correct time had to be calculated on the basis of astronomical observations. The result was then transferred to a high-precision pendulum clock in the salon. Thereafter, this reference time was saved with especially accurate pocket chronometers and then “carried”to the public clocks. It was also communicated to persons and authorities who needed to know the precise time. Subscribers of the timekeeping service included astronomers and watchmakers as well as officials of the nascent railway system.

With its off-centre subsidiary seconds, the dial of the RICHARD LANGE “Referenzuhr” is reminiscent of a historic precursor made in 1811 – a pocket chronometer known to have been used for synchronisation purposes by the timekeeping service. It was crafted by Johann Heinrich Seyffert who did more to promote precision horology in Dresden than any other watchmaker. His most prominent customer, naturalist and explorer Alexander von Humboldt, purchased one of Seyffert’s chronometers for his now acclaimed Latin American expedition.

The RICHARD LANGE “Referenzuhr” features a large balance wheel with eccentric poising weights and a Lange balance spring developed and manufactured in-house. Beating at a frequency of six semi-oscillations per second, it delivers the precision that can be legitimately expected of an instrument designed to serve the sciences. A glance through the sapphire-crystal caseback is a feast for the eyes of those who delight in technical finesse: both the ZERO-RESTART lever mechanism and the winding train are visibly arranged above the three-quarter plate. The strictly limited edition – 50 watches in platinum and 75 in pink gold – underscores the exclusivity of this coveted collector’s item.

The German silver time bridge, coated black with the PVD process, creates a prominent framework for the hour and minute display apertures. Coated with white Superluminova, the glowing numerals seem to float incandescently above the black background. Even at night. This is assured by a dark-tinted sapphire-crystal glass. Its light-permeable coating allows the numerals to be charged with enough photonic energy to uniformly emit it again during the night for several hours. Thus, the LANGE ZEITWERK “Luminous” reliably tells the time in one-minute intervals between dusk and dawn. The switching power is generated by a constant-force escapement between the mainspring barrel and the balance. Concurrently, it makes sure that the flow of power to the balance remains constant throughout the entire power-reserve period. The manufacture calibre L043.1 that delivers the heartbeat of the LANGE ZEITWERK
“Luminous” incorporates all of the refined features that have justifiably transformed the name A. Lange & Söhne into a synonym for unmatched horological quality among connoisseurs around the world. Its highlights include the balance wheel with eccentric poising weights, a balance spring manufactured in-house, and the lavish decorations applied to all movement parts by hand. The design of the watch, showcasing dark/bright contrasts, is emphasised by the platinum case, a black crocodile strap, and the buckle, also crafted from solid platinum.

Data sheet LANGE ZEITWERK “Luminous” Reference 140.035

Movement Lange manufacture calibre L043.1, manually wound, crafted to the most exacting Lange quality standards, decorated and assembled by hand; precision-adjusted in five positions; threequarter plate made of untreated German silver; balance cock engraved by hand; jumping minutes; constant-force escapement

Number of movement parts 388
Jewels 68
Screwed gold chatons 2
Escapement Lever escapement
Oscillation system
Shock-resistant glucydur balance with eccentric poising weights; superior-quality balance spring manufactured in-house with patent-pending attachment system (balance spring clamp), frequency 18,000 semi-oscillations per hour, precision beat adjustment system with lateral setscrew and whiplash spring

Power reserve 36 hours when fully wound


Functions
Jumping hours and minutes, small seconds hand with stop seconds, power-reserve indicator


Case dimensions
Diameter: 41.9 millimetres; height: 12.6 millimetres


Movement dimensions
Diameter: 33.6 millimetres; height: 9.3 millimetres


Case
Platinum



Dial
Coated sapphire crystal; luminous numerals

Time bridge
German silver, PVD-coated

Glass and caseback
Sapphire crystal (hardness 9)

Hands
Rhodiumed gold

Strap
Hand-stitched crocodile strap, black

Buckle
Lange prong buckle in solid platinum


Edition 100 watches

                               Three exceptional timepieces demonstrate the capabilities of A. Lange & Sohne

Part of three exceptional timepieces that demonstrate the capabilities of A. Lange & Sohne.

Data sheet 1815 MOONPHASE    Ref. 212.050

Movement : Lange manufacture calibre L943.2, manually wound, crafted to the most exacting Lange quality standards and largely decorated and assembled by hand; precision-adjusted in five positions; three-quarter plate made of untreated German silver, with sunburst finish; balance cock in honey-coloured gold, engraved by hand

No. of movement parts : 220

No. of jewels : 26

Escapement : Lever escapement

Oscillation system : Shock-resistant glucydur screw balance, superior-quality balance spring manufactured in-house, frequency 21,600 semi-oscillations per hour, whiplash-spring beat adjustment system

Power reserve : 45 hours when fully wound

Functions : Time indicated in hours, minutes, and subsidiary seconds with stop seconds; moon-phase display

Operating elements : Crown for winding the watch and setting the time, push piece for the moon at 10 o’clock

Case dimensions : Diameter: 37.4 millimetres; height: 8.9 millimetres

Movement dimensions : Diameter: 27.5 millimetres; height: 3.9 millimetres

Case : Honey-coloured gold

Dial : Solid gold, argente´, guilloched; lunar disc in solid honey-coloured gold

Hands : Blued steel

Glass and caseback : Antireflection-coated sapphire crystal (hardness 9)

Strap : Hand-stitched, red-brown crocodile strap with Lange prong buckle in solid honey-coloured gold