Designed to celebrate the friendship between John Arnold and Abraham-Louis Breguet, the Constant Force Tourbillon 11 watch has a transparent anti-reflective sapphire crystal case back that showcases the architecture of the A&S5219 calibre, inspired by the back of the timekeeper kept in the British Museum.
Here, the tourbillon carriage, which rotates once every minute, keeps the general design of the carriage used by John Arnold’s brilliant friend in the timepiece intended to commemorate their unbreakable friendship and embody the true scope of their joint research.
The extremely refined tourbillon features a very thin, polished and rounded-off linear carriage bridge that reveals a variable inertia balance with inertia blocks inspired by the most sophisticated oscillators used in John Arnold’s chronometers.
The House also chose to incorporate a T-shaped retaining spring inspired by the one used in the ‘pare-chute’ shock protection system developed by Abraham-Louis Breguet and which can be found on the tourbillon bridge of the original instrument.
However, a Swiss lever escapement, which is more practical and less sensitive to shocks, was chosen over the detent escapement of the original timepiece.
The finishes of the mainplate, bridge and tourbillon cock are virtually identical on both timepieces, while the grained and chamfered barrel bridge of the Constant Force Tourbillon 11 watch features hand-engraved inscriptions and the famous plate, which has a new textinspired by the original: “To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.”
