It happened in 1940 with the wristwatch Reference 1415-1 HU exhibited at the Patek Philippe Museum (Inv. P996), a one-of-a-kind piece probably crafted for a physician.
The Patek Philippe World Time Wristwatch with Chronograph and Pulsometer Scale Reference 1415-1 HU housed in a 41 mm yellow case framing a silvered dial with applied Breguet numerals - 1940
With the new World Time Chronograph Ref. 5930 presented at Baselworld 2016, Patek Philippe is bringing together again these two complementary functions.
The self-winding CH 28-520 PS chronograph calibre with column-wheel control and vertical clutch features the proven World Time module based on a concept developed by Genevan watchmaker Louis Cottier in the 1930s which Patek Philippe further optimized with two important refinements patented in 1959 and 1999.
The chronograph movement and the World Time mechanism were enhanced with extensive modifications. To save millimetres, axes were shifted, bridges thinned and newly designed, and component clearances changed such that the calibre CH 28-520 HU can be properly be considered a new movement.
The chronograph has a start/stop pusher at 2 o'clock and a reset pusher at 4 o'clock that also doubles as a flyback pusher. When it is pressed while the chronograph is running, the sweep hand flies back to zero and a new time measurement is started automatically.
Because the chronograph hand is powered via a vertical clutch, it can also be used as a permanently running seconds hand without risking undue wear and without affecting the rate accuracy and power reserve of the watch.
The World Time function is also very easy to use with the hour and minute hands indicating the time in the city and time zone whose name is shown at 12 o'clock.
The time in the 23 other zones can be quickly and easily determined with the city disk and the two-coloured 24-hour ring which instantly tells the user whether it is day or night in the respective city and time zone.
When travelling from one time zone to the next, pressing the corrector button at 10 o'clock advances the city disk and the 24-hour ring counterclockwise in one-hour steps as well as the hour hand clockwise, also in one-hour steps. The city name at 12 o'clock indicates the destination time zone.
During this process, the World Time mechanism and the hour hand are uncoupled from the movement, so neither the amplitude of the balance nor the steady progression of the minute hand are affected. The chronograph hand also keeps moving without any irregularity.
The classic round case in white gold has a diameter of 39.50 mm and features the same winglet-style strap lugs that were a key design element of the 1940s and 1950s World Time watches.
The time-zone correction button is still at 10 o'clock and has the same rectangular profile as the two chronograph pushers.
The case is endowed with a sapphire-crystal display back that reveals the flawless finish of the movement. The centre of the rotor is decorated with perlage, while the centrifugal mass itself features circular graining and an engraved Calatrava cross.
The outermost display element in blue lists the 24 city names representing the time zones. It has been updated with new cities for some time zones – for instance Dubai instead of Riyadh or Brisbane instead of Nouméa – and takes into account the fact that Moscow changed its local time from UTC+4 to UTC+3.
A small gap between the city disk and the 24-hour ring accommodates the seconds scale for chronograph measurements. It is a narrow white circular scale with fourth-of-a-second graduations. This subdivision reflects the movement frequency of 4 hertz (28,800 A/h), which allows times to be stopped to an accuracy of one-eighth of a second.
The 24-hour ring, which continuously rotates counterclockwise, doubles as a day/night indicator. It has bright numerals on a dark background and a moon symbol for the nocturnal hours as well as dark numerals on a bright background and a sun symbol for the daylight hours.
The centre of the dial sports a hand-guilloched decoration interrupted only by the white-gold index markers and the 30-minute chronograph counter.
Worn on a hand-stitched matt navy blue alligator strap with a white-gold Calatrava fold-over clasp, the new Patek Philippe World Time Chronograph Ref. 5930 has a price of around US$ 73,000. patek.com