ith their new interpretation of the Constant Force Tourbillon 11 Platinum, Arnold & Son pay tribute to the watchmaking genius of the House’s founder. This platinum edition represents the final opus of the Constant Force 11 collection – launched with the gold model – and crowns the celebration of 260 years of heritage. It also celebrates the magic of nature with a dial ornamented with a hand-guilloché surface in the “tremblé” style, evoking the fern-covered moors around Tintagel in Cornwall – the birthplace of John Arnold and setting for the legendary adventures of King Arthur.

Adorned with new refinements, the Constant Force Tourbillon 11 was purposefully designed by Arnold & Son to honour the timepiece that Abraham-Louis Breguet presented to John Roger Arnold in 1808. Now conserved by the British Museum, this historic timepiece, based on John Arnold’s No. 11 chronometer, is believed to be the first tourbillon-regulated watch made by Abraham-Louis Breguet after he filed the patent in 1801.

The Constant Force Tourbillon 11 platinum edition features a distinctive solid gold dial. The fine detail of the “tremblé” is expertly crafted by hand with a burin engraver. Under the controlled motion of the tool, the sharp tip has traced a succession of artfully irregular zigzags. This organic pattern is surprisingly harmonious and takes its inspiration from the wild moors of Cornwall, where ferns curl in fleeting arabesques as the sea winds blow. Each etched curve seems to capture the soul of this mystical land, the birthplace of John Arnold and home to Arthurian legends. The engraving weaves a poetic tie between the master’s watchmaking heritage and the elemental forces that shaped his childhood. The wind, the dancing ferns and the famous mists – all the magic of Cornwall – are reflected in the golden dial, transforming timekeeping into an ode to nature and history.

The dial is meticulously pierced to accommodate the white opal hour and minute subdial, as well as the mechanism delivering constant force to the tourbillon cage. The latter can be seen under an 18-carat gold bridge and rotates in exact, one-second increments. This rhythm is far from insignificant as it carries the legacy of marine chronometry when each second counted was a longitude reclaimed from the ocean.

The classically shaped, rounded case measures 41.5 mm in diameter. Crafted in platinum, it appears exceptionally slender on the wrist. On the dial side, it is fitted with a delicate bezel framing a domed sapphire crystal with an anti-reflective coating on both sides. On the reverse, it features a sapphire case back through which the bridges and the tourbillon of the in-house manual winding A&S5219 calibre can be seen. Water resistant to 3 bar, the watch is worn on a hand-stitched midnight blue alligator leather strap, fastened with a platinum folding clasp.

To ensure perfect isochronism throughout its 100-hour power reserve, Arnold & Son have positioned their patented constant force mechanism between the main gear train and the tourbillon. Visible on the dial, this ingenious system regulates the energy from the barrels, eliminating any variations in torque that could disturb the balance’s oscillation. Second after second, it rearms a finely adjusted spiral guaranteeing a completely stable transmission of energy to the tourbillon cage. The precise choreography of this constant force mechanism is magnified by an 18-carat gold bridge, emphasising the watchmaking excellence.

The constant force mechanism replaces the group of components known as the “fusée-and-chain” that John Arnold used in his chronometers. The advantage of this system is that it not only delivers a constant force to the regulating organ, it also produces a true-beat seconds display. The seconds are not indicated by a traditional seconds hand, but by the tip of the hand-blued anchor, which simultaneously serves as a structural bridge for the constant force mechanism.

This final limited series of 11 pieces pays tribute to the legendary friendship between John Arnold and Abraham-Louis Breguet. Its sapphire case back reveals the A&S5219 calibre, whose architecture is directly inspired by the first regulator with tourbillon created by Abraham-Louis Breguet. This chef-d’oeuvre, housed in the British Museum, was inspired by Arnold’s No. 11 chronometer and offered to his son in 1808. The Constant Force Tourbillon 11 revives this watchmaking bond: its tourbillon cage faithfully reproduces the original design. With extremely pure lines, the tourbillon features a distinctive and remarkably delicate linear, mirror-polished and rounded cage bridge, revealing a variable-inertia balance whose design draws on John Arnold’s most accomplished chronometers. In this true dialogue across time, every component speaks to the extraordinary union of two masters of timekeeping.

The finishing of the main plate, bridge and tourbillon cock is virtually identical to that of the very first tourbillon. To complete the tribute, Arnold & Son have included hand-engraved inscriptions on the barrel bridge and added the famous plate on which another homage has been engraved: “To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.”. This inscription definitively gives the Constant Force Tourbillon 11 its place in a unique historical saga: one in which the friendship between two geniuses gave rise to some of the most remarkable advances in chronometry.

TECHNICAL SPECIFICATIONS

Constant Force Tourbillon 11, Platinum Edition

Functions hours, minutes, true-beat seconds

Movement

• Calibre A&S5219 manual winding mechanical movement, constant force, one-minute tourbillon
• Jewels 35
• Diameter 33 mm
• Height 10.48 mm
• Power reserve 100 hours
• Frequency 3 Hz/21,600 vph

Finishes

• main plate: 3N gold finish, grained, polished angles
• barrel bridge: 3N gold finish, grained, polished angles, stretched edges, hand engraving
• tourbillon bridge: gold finish, grained, polished angles, stretched edges, satin-finished Durnico steel retaining spring
• screws: blued, chamfered, mirror-polished heads
• tourbillon: cage plate with mirror-polished finish, satin-finished pallet bridge, mirror-polished stud holder, rhodium-plated balance, polished and rounded cage bridge
• costant force bridge: 18-carat yellow gold, polished bevel, satin-finished flat surface, polished angles
• lower constant force cage bridge: flame-blued, mirror-polished, polished angles.

• Engraved plate “To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.”

Dial

• 18-carat yellow gold (3N), hand-engraved, Arnold & Son “fern” pattern

Hour dial white opal, concave

Case

• Material platinum (Pt 950)
• Diameter 41.5 mm
• Thickness 13.7 mm
• Crystal domed sapphire with an anti-reflective coating on both sides
• Back sapphire crystal with an anti-reflective coating on both sides
• Water resistance 3 bar (30 metres/100 feet)

Strap

• Material midnight blue alligator leather with black alligator leather lining, hand-stitched
• Clasp folding, platinum (Pt 950)

Reference 1FCBX.Z01A.C0232X

Limited edition 11 pieces

Swiss retail price CHF 140,600 incl. VAT (subject to change)