Pour le Mérite’ is a very French-sounding reference to the Prussian order conferred for exceptional scientific merit. It is also the name of A. Lange & Söhne’s most technically proficient line of timepieces. When introduced in 1994, Pour le Mérite was the first wristwatch with a tourbillon and a fusée-and-chain transmission. Every ‘Pour le Mérite’ watch has used this archaic energy transmission to power the watch. Though technically challenging, a fusée-and-chain transmission ensures a constant torque to the escapement, thereby ensuring accuracy.
In 2005, the Tourbograph ‘Pour le Mérite’ was introduced with a chronograph with the rattrapante function and the trademark fusée-and-chain transmission. The new Tourbograph Perpetual ‘Pour le Mérite’ is the fifth watch in this illustrious line and combines five complications – perpetual calendar, chronograph rattrapante, fusée-and-chain transmission, and tourbillon – in a classically styled watch.
One of the biggest challenges for the watchmakers was keeping the thickness of the watch within reason. Just adding a perpetual calendar module to the 2005 model’s base caliber wouldn’t have cut it. So the team had to redesign the caliber with the perpetual calendar mechanism arranged under the dial around the tourbillon. The addition of an extra layer to the movement has also resulted in the use of a curved tourbillon bridge that has a black-polished finish.
The dial features Arabic numerals, a railway-track minute scale, blued steel hands for the time and rhodiumed gold hands for the calendar seen in a cloverleaf arrangement of the subsidiary dials, a nod to the A. Lange & Söhne pocket watches. The perpetual calendar utilizes the three subsidiary dials to display the date, day of the week, month and leap year. The upper half of the analogue date also accommodates the moonphase display, which is calculated to remain accurate for 122.6 years. Its deep-blue disc is made of solid gold.
Flip the watch over to view the new manufacture caliber L1331 made up of 684 parts. In what is typical of a Lange movement, the finished is superb, with a mix of polished and brushed surfaces and chamfered edges. Cue thermally blued screws, screwed gold chatons, bridges and plates made of untreated German silver and decorated with Glashütte ribbing and perlage and the hand-engraved chronograph bridge. The two column wheels for the chronograph and the rattrapante function are clearly visibly. The tourbillon and the fusée-and-chain transmission offset the two bugbears of a mechanical movement: gravity and waning spring force. The result is improved rate stability and accuracy.
This watch is cased in 43 mm platinum and is only 16.6 mm thick, remarkable considering its horological heft. A limited edition of 50 watches, the latest Pour le Mérite is easily one of the highlights of the event this year.