It’s a dangerous thing to start a new watch company –in addition to an almost infinite number of ill-advised possible business goofs, standing out from the crowd enough for people to notice what you are doing, as well as consistently developing products, marketing, and communications over the several years it can take to get a brand off the ground, is both extremely difficult and very, very expensive. While it’s possible to thrive (at least for a while) on pure marketing, it’s much rarer (and in some ways much riskier) to try to produce something that’s both technically innovative and beautiful.
The two functions are linked –while there are a number of different methods for determining altitude, the one used by Breva in its watches is measurement of air pressure, which decreases with altitude. Changes in air pressure can be measured with a barometer, which can also be used to predict short term changes in weather (a decrease in air pressure often heralds a storm, while rising pressure is associated with good weather.) The barometer was first developed by the Italian scientist Evangelista Torricelli, in 1643, who deduced that the atmosphere must have weight and exert pressure after observing the behavior of water in very tall siphons. Torricelli’s was not only the first barometer, he was also the first to use mercury in a column to measure atmospheric pressure (traditionally given as millimeters of mercury) and he gave his name to a traditional unit of pressure, the torr.
Mercury barometers were and are very accurate but they were also fragile and, of course, mercury is also highly toxic. The Breva watches, therefore, use a type of barometer known as an aneroid barometer, which was first developed in 1844 by the French scientist, Lucien Vidi. The aneroid barometer uses, instead of a column of mercury, a capsule made of a beryllium copper alloy from which most of the air has been evacuated (aneroid means “without air.”) The capsule expands or contracts as external air pressure changes –often, multiple capsules are used to amplify the mechanical distortion achieved and improve precision; the Breva watches use a double capsule system, and we’re also told that a special memory-metal alloy was developed (and is patented by Breva) to optimize performance in a wristwatch.) The tip of a lever rests on the capsule(s) and is deflected as air pressure changes, and the deflection is amplified by a gear train; the mechanism bears certain similarities to that used in mechanical depth gauge watches.
The same problem obtains with Breva’s barometer watches as with mechanical depth gauge watches –in order for the barometer to work, the case has to be open to the external environment. In the current generation of mechanical diver’s watches this is addressed by placing the metal diaphragm on the outside of the case; in the Breva watches, air passes in and out of the case interior through a specially made Teflon filter which allows the ingress and egress of air, but not moisture or dust. Both watches can also be manually calibrated for accuracy –an essential for both the altimeter and weather prediction functions.
The Genié 01 shows altitude on a scale in a sector at the upper left hand side of the dial, from 1 to 5000 meters. The weather prediction dial is on the lower right. Using the watch is, despite the complexity of the mechanism, fairly straightforward. One opens the valve (located at 4:00) to equalize air pressure inside the case with the outside. (The valve is opened by pressing the pusher to read barometric pressure –essentially the watch measures pressure “on demand.”) One then sets the barometer dial, which is moveable, so that the hand rests on “Meteo” (French for “weather forecast.”) Over the next few hours, if the air pressure rises, the hand will move to the right to indicate fair weather; if the pressure drops, to the left, indicating foul. Crucially, the barometer dial can be corrected for changes in altitude (which might give incorrect weather readings) thanks to a scale on the back of the case, which shows the correction in hPa, or hectopascals –a standard international unit of air pressure –for varying altitudes. The altimeter can also be manually calibrated –both altimeter and weather dial can be set using the combined crown-and-pusher at 2:00 (the crown for the weather dial, and the pusher for the altimeter.) The calibration for altitude measurement by change in air pressure is different from that for weather, so though both indications are actuated by a single lever resting on the aneroid capsules, they require different gear trains.
The Genié 02 is a pure high precision altimeter. Like the Genié 01, its altimeter is accurate to 5000 meters; however instead of a weather dial, it sports a high-precision sub-dial for altimetric measurement. It comes in 2 versions –the “Terre” in titanium, with the sub-dial showing increments of 1000 meters; and the “Air” which is in black titanium, and which has the IATA (International Air Transport Association) codes for 20 major airports on the case back along with their altitude. As with Genié 01, the altimeter can be calibrated using the adjuster at 2:00.
The barometers used in Breva’s watches were engineered by Michel Dourde, whose family has been making barometers for four generations –since 1860. The maximum change in height of the aneroid capsules is only 0.2 mm, and the gear system has to magnify this by about 200 times in order to make the change visible –and legible –to the naked eye.
These are remarkable instruments, and Breva’s accomplished something very difficult in producing them; they’ve made highly complicated wrist instruments that are also compellingly beautiful, and with a very rare complication to boot –there have been very, very few barometric and/or altitude measuring watches that are purely mechanical (the Favre-Leuba “Bivouac” altimeter watch from the 1960s being one of this very small group.) We’re not sure where Breva’s going next, but in the meantime, hats off to them for a remarkable achievement, and for giving us one of the most intriguing debuts we’ve seen in years.
Genié 01 is available in a limited edition of 55 pieces in rose gold and 55 pieces in white gold. Genié 02 “Terre” is available in 55 pieces in titanium, and Genié o2 “Air” is available in 55 pieces in black titanium. Much more info available from Breva here.
Source: revo-online.com by JACK FORSTER