An 18-carat gold tribute to the friendship and innovation that helped shape precision timekeeping in the Age of Enlightenment
Arnold & Son’s Constant Force Tourbillon 11 marks its 260th anniversary with a limited edition that’s both technically impressive and historically grounded. Just 11 pieces of this 41.5mm timepiece have been produced, each in 18-carat yellow gold—a nod to the precious metal favoured by John Arnold for his finest marine chronometers.
At its heart is the hand-wound A&S5219 calibre, developed entirely in-house. It features twin barrels delivering a 100-hour power reserve, a patented constant force mechanism visible on the enamel dial, and a tourbillon displayed on the caseback.
The constant force system ensures consistent energy delivery across the power reserve, improving isochronism and enabling a dead-beat seconds display, echoing the precise ticking of Arnold’s naval chronometers.
This watch directly references the 1808 Breguet tourbillon built using the movement from John Arnold’s chronometer No. 11. That historic piece, now in the British Museum, was a personal tribute from Abraham-Louis Breguet to his late friend and collaborator.
The A&S5219 calibre draws on this connection between two of horology’s most influential figures, with movement architecture inspired by the original and a commemorative engraving that echoes Breguet’s own: “To the revered memory of John Arnold and Abraham-Louis Breguet. Friends in their time, legendary watchmakers always.”
On the dial side, the Constant Force Tourbillon 11 features a white grand feu enamel disc with a recessed white opal sub-dial for the time display. The yellow gold bridge supporting the constant force mechanism mirrors the tone of the case, reinforcing the piece’s classical aesthetic.
Through the caseback, the tourbillon is visible rotating once per minute. Its carriage includes a variable inertia balance and a retaining spring inspired by Breguet’s pare-chute shock protection system. While the original chronometer used a detent escapement, Arnold & Son has opted for a more practical Swiss lever for improved shock resistance.
