The F. P. Journe Ruthenium Collection Chronomètre à Résonance
Sometimes brass is more precious than gold.
F. P. Journe’s Chronomètre à Résonance is, of all his watches and complications, the one which collectors and enthusiast will in general most strongly identify with the brand, the man, and his work. The Chronomètre à Résonance was only the second watch F. P. Journe launched (after the Tourbillon Souverain) and it was first shown as a prototype, at the BaselWorld trade show, in 1999. The Chronomètre à Résonance has invited disagreement and controversy ever since its introduction, and whether or not it actually works is debated in some quarters even today. It is, however, based on a well known phenomenon, which is, as the name says, resonance.
We often say just “resonance” when talking about Journe’s resonance watches (and other resonance watches, or given the amount of argument which resonance watches seem to evoke, maybe I should say, claimed resonance watches). However, resonance — harmonic resonance — is simply the tendency for any system (like a spring or pendulum) with a natural frequency, to respond with greater amplitude when the frequency of its oscillations matches its natural frequency. This is a good thing in watches and pendulums — get them swinging at their natural frequency and it takes very little energy to keep them swinging, which is why the almost homeopathic amount of energy delivered by the lever escapement can keep the balance chugging away. (An example of destructive harmonic resonance often cited is the collapse of the Tacoma Narrows Bridge, although it turns out that the real reason “Galloping Gertie” fell down in 1940, less than a year after it opened, involved a phenomenon called aeroelastic flutter as well).
Harmonic resonance is different from sympathetic resonance, which is the phenomenon at play in the Journe resonance watches. In this situation, two oscillators with the same natural frequency will begin to beat in synchrony with each other when placed in close proximity, and if they are somehow connected mechanically. A classic example is two tuning forks tuned to the same note — strike one, and if you hold it close enough to the other, the second tuning fork will start to vibrate as well. In horology, the phenomenon was first observed in pendulum clocks, by their inventor, Christiaan Huygens, who designed the first successful pendulum clock in 1657. He observed that two pendulum clocks mounted on the same shelf or bracket, would tend to start to swing in beat with each other. The phenomenon was later explored in clocks by Antide Janvier, and by Abraham Louis Breguet in his resonance pocket watches, only three of which are known to exist today.
The basic idea behind a watch or clock using sympathetic resonance with two oscillators, is that the two oscillators together will tend to have a more stable rate than a single oscillator beating in isolation. Breguet himself conducted many experiments with sympathetic resonance – at one point, he suspected that air turbulence was coupling the two balances, so he placed one in a vacuum chamber, and also experimented with placing a thin metal barrier between the two. In both cases, the balances began to beat in time with each other despite the absence of air friction, and Breguet concluded that the phenomenon — however unlikely it might seem — was real.
Mechanical coupling appears to occur in Breguet’s, and Journe’s, resonance watches thanks to the minute forces exerted on the movement plate by the balance spring, at the extreme limits of its oscillations. The amount of energy in question is minute, so the balances have to be adjusted to a closely matched rate. Breguet found, in his pocket watches, that the balances had to be within 20 seconds of each other for sympathetic resonance to occur. In the much smaller Journe wristwatches, the balances must be matched in rate within 5 seconds a day or less.
Each of the balances is driven by an independent gear train, although a single mainspring drives both trains. Energy is evenly divided between the two gear trains by a differential system. In order to ensure absolutely unvarying energy in both oscillator systems, each independent train has the constance force device known as a remontoir, mounted on one of the gear train wheels. The remontoir is essentially a second driving spring, which is rewound at set intervals by the primary mainspring and its purpose is to deliver unchanging torque to the two balances. The spring remontoire has a very long history in high precision timekeeping — it was originally invented by the English horologist, John Harrison, for his marine chronometers (one of which became the world’s first successful marine chronometer after its completion in 1759.
All of Journe’s resonance chronometers are unusual and extraordinary watches. The Ruthenium Collection models, however, are especially notable not just for their ingenuity, or for the fascinating action of the two balances (when they are in resonance, the seconds hands tick in time with each other as well) but also for their rarity. Journe is famous today for his 18 karat gold movements, which he began to make in 2004, but prior to that, his movements were made of brass — the standard material for watch movements for centuries. It’s standard in watchmaking to plate brass movements with rhodium, a platinum group metal — this resists corrosion and also gives the movement, after further finishing, a jewel-like appearance. Journe’s early brass movements were plated with ruthenium, another platinum group metal, and his total production of all brass movements is thought to be around 2000 watches, making them rarities. The brass-movement Journe watches are very attractive to collectors, thanks to both their rarity, and to their place in the history of Journe’s watchmaking.
A very small number of early F. P. Journe watches form what’s known as the Ruthenium Collection, which brings us to the watch we’re looking at for this installment of A Watch A Week. The Ruthenium Collection watches were produced for a relatively short time — between 2001 and 2005 — in five different models, each of which was a small series. Just 99 of the Ruthenium Collection Chronomètre à Résonance watches were made, in platinum cases, with ruthenium plated gold dials (ruthenium dials are the common characteristic of the Ruthenium collection watches) with guilloché silver subdials.
The rarity of the Chronomètre à Résonance watches in ruthenium, along with the technical sophistication of the watch, has made them one of the ultimate prizes for serious collectors — rare, beautiful, and a feast for both the mind and the eye.