In 1795, Abraham-Louis Breguet wrote a letter to his son, in which he described a new type of timekeeper. “I have invented a means of setting a watch to time, and regulating it, without anyone having to do it … then every night on going to bed, you put the watch into the clock. In the morning, or one hour later, it will be exactly to time with the clock. It is not even necessary to open the watch.”
That ‘pendule sympatique’ clock was the first of a new range of clocks, which advanced the art of precision timekeeping, as well as ingenious mechanical solutions as an intellectual entertainment or even an art form.
Pendule Sympathique by AL Breguet circa 1795; self-synchronising pocketwatch based on the clock time at 12 o’clock.
These new clocks worked with specially designed watches. The clocks would act as master timekeepers, and control the rate and time-setting of the watches. The owner would place the watch in a special cradle on the top of the clock, and at a certain hour, the clock would set the watch to the correct time, and adjust the rate of the watch to compensate for its gain or loss. That was an amazing achievement 220 years ago.
Today, the idea of a master-clock that controls the accuracy and rate of a slave-clock, is how our cell phones, smart watches, and radio-controlled wristwatches work. They rely on atomic master clocks and are synchronised electronically via radio waves or the Internet. However, the art of making a mechanical watch, which is controlled via a mechanical linkage to a master clock, has been revived by the Urwerk AMC.
URWERK has made the first master-slave clock and wristwatch, where an atomic clock, via a complex mechanical linkage, duplicates all of the functions of Breguet’s most advanced sympathique clock in one device: it winds, sets, and regulates an URWERK watch, which rests in a cradle in the case of the atomic clock. Both the atomic master clock and the watch have been specially designed for the AMC project, and together they represent the first time that a purely mechanical watch and an atomic clock have been created to perform these three operations via mechanical linkages.
URWERK co-founder Felix Baumgartner describes the inspiration for the URWERK AMC: “My father, who specializes in precision and decorative clocks from the 17th to the 20th centuries, introduced me to the golden age of horology. It was an age of invention by the great masters of the craft: Berthoud, Leroy, Houriet and Abraham-Louis Breguet. One evening he opened a book to show me a most ingenious clock — Breguet’s Pendule Sympathique. He started telling me the story of this clock, which is like a fairy tale. There were only a handful of them made and they all went to the leading personalities of the era.”
The outcome of this inspiration is a marriage of the tradition of mechanical horology, with the most precise timekeeping technology in human history.
The Atomic Clock
We won’t go into the full geekiness of quantum physics to describe the atomic clock. Suffice to say that it works by measuring the cycles of the radiation emitted by radioactive material. In fact, this URERK AMC atomic clock uses two types of ions of YIG (yttrium iron garnet) and rubidium encased in solid aluminium measuring 45cm x 30cm x 18cm and weighs approximately 35 kilos.
The clock is co-developed with TimeStandard and is adaptable to any mains voltage available worldwide (90 to 240 volts). Special circuitry compensates for temperature change, variations in power supply, and aging of the atomic timing package itself. The AMC atomic clock will keep nearly perfect time; guaranteed to within one second in 317 years.
URWERK has been developing electromechanical control precision timekeeping in watches for almost a decade. This mechanical watch is designed specifically for the AMC project. It includes typical URWERK features such as the power reserve indicator and two stacked mainspring barrels for a power reserve of four days. The watch has URWERK’s “Oil Change Indicator”, which shows when the movement should be serviced. One full rotation of the oil change indicator will take more than four years, with a recommended service after three and a half years of operation.
The really clever bit is unseen. This watch is designed to fit on and work with its Atomic Master Clock (AMC). This master clock will rewind the Urwerk wristwatch, set it to the correct time and if necessary, adjust its rate.
This world’s first brings together in a single mechanism all the functions of the various historical sympathetic clocks made by Abraham-Louis Breguet.
In Breguet’s sympathique clocks, the mechanism for adjusting the rate is inside the watch, and triggered by an actuating rod extending from the clock into the watch, when the clock reads a specific time. In the AMC, the same principle is followed. At the time for rate adjustment, a pusher extends from the clock into the watch to ‘read’ the time difference from standard time. If the time of the atomic clock and that of the watch are exactly synchronized, to the second, nothing happens. Any deviation in rate is adjusted by the automatic mechanism moving the index lever adjustment of the watch, like a watchmaker would manually. The index lever is that bit of the movement that is marked + or – seconds.
Synchronisation of Minutes and Seconds
The exact synchronization of the minutes and seconds display of the watch with that of the atomic clock is achieved by a pusher triggered by the atomic clock at a certain time. Two levers are activated to “zero” the seconds wheel and the minutes hand. The watch is now synchronized with the clock.
Winding the Watch
The system for winding the watch is straightforward: a shaft extending from the clock acts on the crown to wind the watch when the latter is placed in its cradle at night.
Both components of the URWERK AMC are at the forefront of their respective classes for timekeeping.
The atomic clock is the current global standard for precision and stability of timekeeping electronically.
The mechanical watch with its 80 hours spring power reserve, Swiss lever escapement and linear balance wheel is at the epitome of mechanical horology.
Linking the two approaches to timekeeping brings together the evolution of horology through the combination of atomic, mechanical and electronic systems.
It is likely that three unique pieces will be constructed by URWERK over the next 2 years.
No prices have been announced but speculation of $3 Million have been mooted and nobody has blinked!
Author’s Biography: Melvyn Teillol-Foo (MTF)
Dr Melvyn Teillol-Foo is a contributor on AlphaLuxe web-zine.
He is also a moderator on PuristSPro.com horology discussion fora. He blends his scientific medical objectivity from the pharmaceutical industry with purist passion, in his musings about watches, travel, wine, food and other epicurean delights.
His travelogue ‘Lazing’ and feasting ‘Grazing’ series of articles have now passed into “mythic legend” on the original ‘ThePuristS.com’ website. Those were the halcyon days when he was “rich and famous” that he remembers with bittersweet fondness.
Dr Teillol-Foo is a quoted enthusiast on the watch industry, appearing in feature articles and interviews by Wall Street Journal, International Herald Tribune, Sunday Times (London), Chronos (Japan), Citizen Hedonist (France) and other publications. He has authored articles for magazines like International Watch (iW) – both U.S. & Chinese editions, ICON (Singapore), August Man (Singapore), Comfort (China) and The Watch (Hong Kong).