HERE AND ELSEWHERE DUAL TIME BY ARNOLD & SON

nowing the time determines your location. This fact has been proven throughout the history of high-sea navigation thanks to its close ties to watchmaking. Dual time zones are central to Arnold & Son’s history, with the marine chronometers of yesterday and today’s two iconic models, the DTE and DBG Skeleton.

Before the advent of marine chronometers in the 18th century, a captain was able to determine the position of his ship on the northsouth axis, i.e. its latitude. However, as the Earth turns on an eastwest axis, the traditional points of reference (the sun and stars) could not be used to determine its longitude. The problem was solved with watchmaking. A highly accurate clock was taken on board and kept at the time at the starting point. As the ship advanced, the captain measured the time specific to its position by looking for noon. The difference between the local and original times allowed him to assess progress across the seas. The marine chronometer was born.

In the wake of these inventions, John Arnold (17361799) proved himself to be one of the most inventive watchmakers of his generation and of the golden age of timekeeping. Indeed, Arnold worked ceaselessly to perfect, miniaturise and enhance the reliability of his marine chronometers. By helping to popularise chronometer technology, his name became indissociable from the history of maritime navigation and the conquests made possible by the very concept of dual time.

Duality

To pay homage to its founder, Arnold & Son has always treated dual time with a particular degree of sophistication and accuracy. Instead of the traditional GMT system where an hour hand in the centre indicates the secondary hour, Arnold & Son chose to give each of the two time zones a dedicated regulating organ to recall the duality of the measurement methods – one horological, the other astronomical – used aboard English frigates.

DTE, Double Tourbillon Escapement

The DTE model combines Dual Time with two tourbillons. In the A&S8513 calibre, they are connected by a common motor organ, a pair of barrels providing a running time of 90 hours. These barrels then supply each of the separate gear trains, which each end in a tourbillon. These independent components in

the dials. The local time zone is indicated by hands with a skeletonised tip and Roman numerals, while the reference time zone is distinguished by solid-tip hands and Arabic numerals. The day/night indicator at 12 o’clock uses the same hand design to differentiate between the time zones. To add to the symmetry of the DBG Skeleton, two crowns sit opposite each other at 3 o’clock and 9 o’clock. This makes it possible to adjust each time zone independently, while the double barrel is wound simply by the crown at 3 o’clock.

Housed in a rose gold case measuring 44 mm in diameter, the entirely skeletonised A&S1309 manufacture calibre is meticulously worked, with chamfered and polished rhodium-finished bridges complete with satin-finished surfaces. On the back, the mainplate reveals a rhodium treatment decorated with Côtes de Genève, while the wheels are satin-finished to add a noticeable contrast.

Accuracy