The Arnold & Son Constant Force Tourbillon 11

Arnold & Son presents the limited edition Constant Force Tourbillon 11, a classical beauty inspired by the first tourbillon created by Abraham-Louis Breguet based on John Arnold’s marine chronometer movement no. 11. Reunited once again, the yellow gold watch, with a constant force mechanism on the dial and a tourbillon regulator on the caseback, is a fitting tribute to the two legendary watchmakers.

Two of the most illustrious minds in horology in the second half of the 18^th century, John Arnold (1736-1799) and Abraham-Louis Breguet (1747-1823), forged a friendship based on mutual admiration. Arnold was taken by the understated design of Breguet’s watches, while Breguet was fascinated by Arnold’s deceptively simple mechanisms capable of levels of chronometric precision that no other watchmaker of the time could emulate. Breguet travelled frequently to London between 1789 and 1791, sharing knowledge and breakthroughs in the science of timekeeping with Arnold.

While Arnold concentrated on optimising his detent escapement and developing balances to mass-produce marine chronometers for the British Admiralty, Breguet continued to work on his “rotating carriage” or tourbillon. In honour of his English friend, Breguet based his first tourbillon regulator on the movement of Arnold’s marine chronometer no. 11. Now exhibited in the British Museum, Breguet’s tourbillon features a plaque inscribed with the following dedication: “The first tourbillon regulator by Breguet incorporated in one of the first works of Arnold. Breguet’s homage to the revered memory of Arnold. Presented to his son in the year 1808.”

Arnold & Son pays homage to John Arnold’s pocket watches with its classical 41.5mm yellow gold case design. The slim bezel, with a slightly domed sapphire crystal, frames the beautiful Grand Feu enamel dial, a nod to Arnold’s marine chronometers. Produced by a specialised enameller, the lustrous white enamel dial features two openings for the constant force mechanism and the white opal sub-dial with black Roman numerals. For the first time at Arnold & Son, the opal sub-dial is concave and placed at an angle to enhance legibility.

Powered by the manual-winding A&S5219 calibre, the patented constant force mechanism between the going train and the tourbillon can be appreciated on the dial. It is designed to smooth out the energy delivered by the two barrels, preventing excessive or insufficient torque from affecting the oscillations of the balance in the tourbillon cage. A yellow gold openworked bridge secures the constant force mechanism and enables a deadbeat seconds indication via the flame-blued anchor on the constant force mechanism.

Inspired by the timepiece in the British Museum, the caseback reveals the one-minute tourbillon carriage secured by a thin, polished, rounded bridge with a variable inertia balance. Moreover, the T-shaped retaining spring is inspired by Breguet’s para-chute shock protection system. However, instead of the detent escapement of the original, the watch has a Swiss lever escapement and twin barrels for the robust 100-hour power reserve.

Beautifully hand-finished with blued screws and golden, grained and bevelled barrel and tourbillon bridges, there is a new hand-engraved text that reads: “To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.” Limited to 11 timepieces, the watch retails for CHF 129,800 (incl. tax). More information at arnoldandson.com.