The Atmos Clock–It Runs On Thin Air

Saturday saw us drinking champagne outdoors at a wedding reception in Wirral. Last night we turned the central heating on for the first time this year. Talk about a change in the weather. Yes, this column is about atmospheric changes, but actually clocks, not barometers. They’re called Atmos clocks and they’re expensive when new, incredibly accurate and they run quite literally on thin air.

Click here to see a slideshow of Atmos Clocks

I’ve been fascinated by clocks ever since I was a boy. I used to take them apart in ham-fisted attempts to repair them – sometimes I actually got them to work again, but not often. I think I caught the bug from my father, an inveterate tinkerer. I remember the time he tried to get a cuckoo clock to work using bottles of tomato and brown sauce as weights to drive the going and striking trains. But I digress.

It’s possible to pay anything from £8,000-10,000 for a new Atmos clock, so well out of my reach. The nearest I ever came was a £95, so-called anniversary clock which dated from the

1930s, said to run for a year on a single wind of the mechanism. You wind it on your birthday or wedding anniversary, see?

Mine never did, for they are temperamental so and so’s. But they are elegant and somehow hugely relaxing to watch. The movement is protected from the elements by a glass dome and the pendulum is a rotating horizontal weight, set with brass orbs or sometimes, capstans. And that’s it. The weight rotates lazily one way and then the other, encouraging its owner to relax and wind down, so to speak. For the money, it’s the nearest thing you’re every likely to get to perpetual motion.

Leonardo da Vinci, among others, was fascinated by the quest to achieve motion without an external source of energy. He failed, as did a young Paris engineer named Jean-Leon Reutter. In 1928, the latter claimed to have succeeded with his clock, which harnessed the energy given off by mercury when it was subjected to changes in temperature or atmospheric pressure.

You’ve seen something similar in the drinking bird toy seen on countless fairground and seaside stalls, apparently destined forever to swing forward and back, dipping its beak into a glass of water and also claimed to be in perpetual motion. Like Reutter’s clock, it is not. Both require energy from somewhere else.

In the Atmos clock, however, its owner has a Swiss precision-made timepiece that operates virtually with no friction to its moving parts and a working life said to be more than 600 years (although a service every 20 years is recommended).

Interestingly, Reutter also drew his inspiration from the anniversary clock, which reached the height of its popularity around the same time he began his experiments. His aim was to produce a movement that required the least possible amount of energy to make it run. He achieved this by making bearings from watchmaker’s jewels and reducing the movement in the escapement to an absolute minimum.

Secret of his success, however, was his design of a minute, thermometer-like glass tube sealed inside a small metal cylinder, which acted like bellows. Changes in temperature and atmospheric pressure cause the bellows to expand and contract, keeping the clock’s mainspring wound continually. The Atmos was born.

Later safety requirements saw the mercury replaced with a gas called ethyl chloride, but the result was the same. It is said that a change in temperature of just one degree is sufficient to run the clock for two days, while the energy used to light a 15 watt bulb would run 60 million Atmos clocks simultaneously.

Manufacturers were sceptical of the claims made by Reutter for the clock and enthusiasm for it was lacking. By a stroke of luck, though, he cashed in on his invention by selling the patent to the important Swiss watchmakers, LeCoultre, whose manager happened to see one of the clocks in a Paris jeweller’s shop window. Mesmerised by it and the claims of perpetual motion, he bought the clock and sought out its inventor.

LeCoultre subsequently merged with its French rival watch company Jaeger and the Atmos clock continues to be made entirely by hand exclusively by Jaeger-LeCoultre, who boast similarly exclusive clients. Own an Atmos clock and you join a group which has included the Pope, Winston Churchill and Ronald Reagan among its number.

The old cliché about being presented with a gold clock on retirement is often the source of many Atmos models appearing on the secondhand market. Recipients die off or might prefer the cash and so the saleroom can be a happy hunting ground. Prices are usually a fraction of the cost new.

However, they might not be the bargain they appear. Like any highly tuned instrument, Atmos clocks can be temperamental. They will work only if they are on an absolutely level surface and kept completely stable. A mantelpiece works, a side table does not.

Repair is a matter for only the most highly skilled specialist and maintenance, specially for a newly-acquired clock, is both recommended and essential. Force a badly set up clock to work against its wishes and irreparable damage can result. The cost of parts and paying for damage to be repaired can be as much as you paid for the clock.