The Atmos clock

The history of the ATMOS clock:

In the late 1920ies, a young Parisian engineer called Jean-Léon Reutter experimented with a clock that would run without direct mechanic or electric energy. He dreamt of a clock that could run simply by using the energy of its surrounding – air and temperature.
For centuries, many scientists such as Leonardo Da Vinci have been experimenting with the idea of perpetual motion. Pierre de Rivaz (1740), James Cox or John Merlin (1760) all tried to invent a technique that could use energy from temperature and air pressure changes to run a clock. But only J.L. Reutter finally succeeded. The dream of perpetual motionlet J.L. Reutter produce a movement that only requires a minimum of energy to function it has, so to speak, no friction loss to nevertheless operate satisfactorily with an absolute minimum of energy.

aus Originalprospekt Reutter ATMOS

A copy of an original leaflet by Reutter ATMOS

After studying the construction of 400day clocks, which at that time were indeed very popular, J.L. Reutter significantly changed the concept of these clocks. Reutter´s modifications of the 400-day clock changed the inhibition, the leverage and the bearing jewels. His new watch ran better and was very reliable. Reutter worked as a Radiologic Engineerat the Company Generale de Radiologie“, which in 1929 started with the production of  the Reutter ATMOS“, with J. L. Reutter being the manager of this first production. His new design of the clock included a very specific construction part, which should provide the clock with enough energy to run for a lifetime.

Funktionsweise Quecksilbermotor Reutter ATMOS

Mechanism of the mercury and ammonia-filled glass tubes inside of a Reutter ATMOS

For this, he used two little glass containers, connected with each other in the overall shape of a “U” (see picture on the right). They were filled with mercury and a small amount of ammonia. This filling reacted to the slightest of temperature change, changed the center of gravity of the  glass container and, as a result, moved forwards and backwards. This movement then wound the mainspring and allowed the clock to move with a mechanism that operated on temperature changes alone. This little glass construction is nowadays part of the bellow of the modern atmos.

The result of Reutters work on the original cock was a new kind of clock different from anything known until then. Reutters clock could run for years without human intervention. It runs based on the slightest of temperature changes, which is why it is called ATMOS Clock.
For those of you who are interested in the physical details:

New measurements of a clock Kal 540 have shown that the average energy required for an ATMOS of this kind is as low as 0,033 microwatts. 15% of this is consumed by the moving pendulum, but most of it (85%) is used by the moving mechanism.

Ref.:Publication Clemson University 1-2015 Operating Principles, Common Questions, and Performance Data for an Atmospheric Driven Atmos Clock S.:12

Ref.:Publication Clemson University 1-2015 Operating Principles, Common Questions, and Performance Data for an Atmospheric Driven Atmos Clock S.:12

Schnittbild ATMOS Kal 540

ATMOS Kal 540

The beginning of production in the early thirties was slow and the lack of enthusiasm during this time made the production of ATMOS difficult. From 1938 on a new design of the vacuum unit was introduced. It replaced the somewhat risky and fragile glass tube system. Meanwhile, LeCoultre had officially acquired all legal rights to the ATMOS clock in 1935 and worked for a couple of years to further refine Reutter´s concept. LeCoultre also aimed to solve a couple of existing problems with Reutter´s system, such as the actual function of the bellow.

The technical concept behind the new bellow, filled with ehtyl chloride, is remarkable: Inside of the capsule is a mixture of gas and liquid which expands when the temperature of the environment changes. It is being pushed together by a counter spring system when the temperature sinks again. This little movement winds up a winding spring. A change of temperature as small as one degee per day is being transferred into enough energy for the clock to run for more than two days straight.

Production of the Atmos II began and was joined by the production of ATMOS III, a slightly improved Model. By 1952, 50.000 ATMOS II and ATMOS III had been sold.

In 1979, when the ATMOS turned 50., LeCoultre produced a limited number of “Birthday-Atmos”-Clocks, the so-called “Jublié”, limited to 1500 pieces – you can have a closer look at one of them in my collection.

ATMOS Jubilé

ATMOS Jubilé

Furthermore, in 1979 the number of sold ATMOS clocks reached a total of 500.000. The combination of knowledge and know-how of Ed Jaeger, who had joined LeCoultre in the thirties to form “Jaeger-LeCoultre” had made the ATMOS Clocks even more popular and contributed to this great success. She is now a real part of Watchmaking history and keeps on fascinating people all over the world.

You can have a look at all kinds of different ATMOS Clocks, models and special editions in our gallery .