June 07, 2022

The myth of perpetual motion has always fascinated humankind because of its infinite possibilities-but. Unfortunately, it is only a myth, impossible because of the universal laws upon which our world is articulated. Although, as we shall see, there are rare instances where motion appears to be perpetual, even if in fact it is not, creating a mechanism that runs continuously is possible, even if it is not, in fact, truly "perpetual" motion!

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What is a perpetual motion watch?

The concept of perpetual motion, as we said, has always been fascinating and has had a profound influence on watchmaking, which - let's face it - has a very deep relationship with eternity! So much so that the first automatic winding mechanism created by Rolex was indeed christened "Perpetual" by Hans Wilsdorf himself.

The Rolex Perpetual was the first among automatic watches featuring a central rotor, a 1931 patent that remained proprietary until 1941 when Felsa improved it and launched its Bidynator. And we have to add that the House of the Crown's patent was not the first modern automatic winding watch movement. Instead, it followed an earlier one, filed by Englishman John Harwood el 1928, who had invented the automatic watch with bumper winding.

In all cases, however, this use of "perpetual" is a misnomer: there is nothing endless about a mechanism wound by our wrist's movement. In fact, if the watch does not move, and thus, the rotor or bumper inside is not activated, this mechanism does not wind the mainspring, and thus after a certain period, the watch stops ticking and tocking. To wind an automatic watch, you need movement, either from your arm or a watch winder!

 

How does perpetual motion work?

Physics tested the concept of perpetual motion endlessly: it cannot exist precisely because no system produces more energy than it receives. As someone who knew about it, Max Planck, a Nobel Prize-winning German physicist and one of the founders of quantum physics, asserted, "It is impossible to achieve perpetual motion by mechanical, thermal, chemical, or any other method, that is, it is impossible to construct an engine that works continuously and produces work or kinetic energy out of nothing."

Let us consider a pendulum: if we swing it, its oscillations will gradually reduce until they cease altogether due to air resistance, causing friction and helping to "absorb" the energy we have imparted to the pendulum itself. It is precisely that friction cannot be eliminated under normal conditions that make perpetual motion machines impossible to exist.

Yet, as we were saying, there is a clock that does indeed appear to be running on perpetual motion, and it is a very special industrially produced (though rather expensive) clock, the Jaeger LeCoultre Atmos. This timepiece works thanks to a traditional spring-powered barrel by a chamber that contains a very temperature-sensitive gas, ethyl chloride. When the gas expands due to rising temperatures, it winds a standard mainspring that ensures the watch's autonomy.

In the latest models, the difference of just one degree Celsius in temperature ensures a 4.3-day autonomy, which makes this unique watch closest to the concept of a "perpetual watch." More, its precision puts to shame almost every manual winding or automatic watch accuracy in the world.

It should also be noted that the Atmos is but the most recent development in a series of older clocks, dating as far back as the early 1600s, developed by Cornelius Drebbel, an eclectic Dutch inventor. He created as many as eighteen for various European kings. One timepiece built on this principle, the so-called Beverly Clock, made in 1864, is still running without ever having been wound since. 

perpetual calendar

What do you call a watch that charges by movement?

As we have seen, and as physics holds through its thermodynamics laws, it is impossible to create a totally "perpetual machine." It follows from all this that this designation, while suggestive, is not accurate (even if a modern automatic watch lifespan could be almost eternal).

And in fact, in the intervening years, the "Perpetual" designation touted by Rolex has been disappearing, being replaced by the more accurate indication of "self-winding movement"- in short, "automatic movement." To this day, any movement that uses the motion of the arms to wind the watchspring is generally - and more correctly - referred to as automatic, not perpetual.

Also, remember that today we have hybrid movements which combine features of mechanical and quartz watches, such as the Kinetic and the Spring Drive, both mounted in Seiko watches, that are not completely mechanical but use the automatic winding system to charge a special movement. However, neither of them is a "perpetual" movement, as they rely to an external source to provide windup power. If you need help to check the kind of movement inside a watch, you can consult our article about watch movement identification.

 

Is perpetual the same as automatic?

If we examine the watches produced by Rolex, we can find that the Oyster Perpetual is the company's basic model, which is then developed with other features.

The model without the date display is simply called the Oyster Perpetual; the one with the date is called the Oyster Perpetual Datejust (Datejust for short); finally, the one with the date and day is the Oyster Perpetual DayDate (DayDate for short).

However, not even Rolex claims that these are genuinely perpetual watches! Instead, this is a historical designation that has obviously been maintained over the years, precisely because the first Rolex Oyster Perpetual dates precisely from 1931. 

So when you talk about Perpetual, you have to be careful what you mean. If you want to refer to the Rolex model, Perpetual is absolutely correct. If, on the other hand, you want to refer to an automatic winding mechanical watch, the most accurate term for it is just that: automatic watch movement. So we can say that the Perpetual is an automatic watch, but only some automatic watches are Perpetual! 

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Main Takeaways

As we have seen, designations in watchmaking are sometimes imprecise, leading to errors and misunderstandings. Therefore, it is always helpful to use more correct terms to define specific features of watches, even if they are perhaps less romantic than others.

Still, this topic is useful for talking about little-known timepieces and, above all, about a fundamental aspect of horology: there is always much to discover when one goes digging into the past of this very special and fascinating field of knowledge.

The Davosa-USA.com website is NOT affiliated in any way with Audemars Piguet,  Blancpain, Franck Muller USA, Inc. or Richemont Companies, Seiko, or any other brand which is not Davosa Swiss. Rolex is a registered trademark of Rolex USA. Davosa-USA website is not an authorized dealer, reseller, or distributor for Rolex and is in NO WAY affiliated with Rolex SA or Rolex USA or any other brand besides Davosa Swiss.
June 07, 2022 — Davosa Editor

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