The brand behind the world’s fastest triple-axis tourbillon and the only one set with precious stones, Purnell holds a unique standing in the landscape of contemporary watchmaking.
When Purnell first introduced their Escape II Collection, the brand boldly stated that it would only produce tourbillon movements, with the aim of making them sensationally visual and emotionally evocative. In partnership with experienced watchmaker Eric Coudray, Purnell decided to approach the historically significant invention with a modern and artistic flair. It was a perspective that acknowledged the mechanism’s evolution in the last 220 years— the tourbillon’s relevance in modern watchmaking is anchored in its symbolism, a seal of technical innovation, quality and mechanical prowess. It was in that spirit that Coudray invented what he dubbed the Double Spherion, which in 2021 remains the world’s fastest twin triple-axis tourbillon.
Coudray based the construction of the Spherion on an escapement invented by American watchmaker Albert H. Potter in 1875, which was eventually abandoned by the industry due to its high cost and manufacturing complexity as well as its energy consumption. Unlike a traditional tourbillon, where the escape wheel, pallet-lever and balance are typically all in the same cage, the Spherion has three nestled cages with the escapement and balance mounted on the innermost cage, the idea being that exposing the balance to a greater variety of positions plus the combined rotation of three cages is more effective at averaging out gravitational errors. The result is a triple-axis tourbillon composed of three cages (inner, median and outer), each making a full rotation in 8, 16 and 30 seconds respectively.
The Spherion is to date the world’s fastest triple-axis tourbillon, and as if one wasn’t enough, Coudray managed to create the movement featuring the Double Spherion, each revolving in opposite directions thanks to a differential system he devised. Unsurprisingly for this movement, the two triple-axis tourbillons require a lot of energy. To account for this, the outer cage is made of titanium, an ultra-lightweight material, and the movement has six barrels arranged in two side-by-side stacks of three, with two visible barrel covers (engraved with Purnell’s credo), offering a 32-hour power reserve.
The Double Spherion was unveiled in the P03 calibre weighing only 15.7 grams and powering the Escape II collection. The unique case design and domed sapphire crystal puts the Double Spherion in full view through a window between the lugs at 6 o’clock and a lateral window at 9 o’clock. Dizzyingly fast and mesmerising to watch, the Double Spherion more than fulfilled Purnell’s aim to make a mechanism that was visually attractive and symbolised a modern interpretation of the tourbillon. And that was only the beginning. Shortly after presenting the Escape II Collection with its Double Spherion, Purnell also unveiled the Escape II Treasure, fully set with diamonds and precious stones on the dial and case, and featuring diamonds adorning the outer cages of the Double Spherion. While other brands had managed by then to set the bridge of a tourbillon, never before had the outer cages of a triple-axis tourbillon been successfully set with precious stones or diamonds.
While the original Spherion weighed 0.79562 grams, the diamond-set versions weighed barely more at 0.831 grams. Nonetheless, even microscopic changes in weight distribution can affect the performance of a movement, so the overall weight of the cages was re-balanced – despite the addition of diamonds, the triple-axis tourbillon weighed the same whether the Double Spherion was set with diamonds or not, therefore leaving its rotational speeds unaltered. Calling it a “Dance of Diamonds”, Purnell managed to obtain one world record with its Double Spherion but also a world first with its diamond-set Double Spherion, two feats made possible by its close partnership with Eric Coudray and commitment to remain 100% Swiss Made. The Double Spherion, a spectacular show of mechanical muscle, demonstrates the tourbillon’s grandeur and contemporaneity in the 21st century watchmaking landscape.
*This year GMT Magazine and WorldTempus have embarked on the ambitious project of summarising the last 20 years of the Tourbillon in The Millennium Watch Book - Tourbillons, a big, beautifully laid out coffee table book. This article is an extract. The Millennium Watch Book - Tourbillons is available on www.the-watch-book.com, in French and English.
