More References on V&C's World Time Watches
Here is a partial list of earlier references which predate this article from The Hour Lounge and should be recognized for their contribution to the subject.
Anton Kreuzer's book, Augenweide Armbanduhr: Vacheron Constantin (Carinthia Verlag Klagenfurt 1992), includes a brief section on the world time wrist watch. Kreuzer recounts the development of Greenwich Mean Time in 1893, which divided the globe into 24 time zones centred on London. While initially an aid to maritime then train travel, the advent of air traffic and worldwide telephone service made the system even more relevant. Here I will translate from Kreuzer's book:
The clock factories gradually implemented this development over the later thirty years by bringing world time models into the clock collections. The wrist watches of Patek Philippe, Agassiz and Rolex were based on a construction of Geneva clock maker Louis Cottier. When Vacheron Constantin decided in the fifties to build such a universal wrist watch, they also chose the system of Cottier's. Three pieces were produced which received the Reference number 6213 and this one was sold in 1957. This World Clock with the signature of Vacheron & Constantin was a relatively large model with a diameter of 40 mm. The dial consisted of three indications (from the inside outward): hourly dial, 24-hour scale with day/night marking, and ring with 42 important city names from all continents. The disk with the labels of cities could rotate by means of a small pusher in the winding crown. The clockwork was calibre 499 (Breguet spiral, 21 jewels, micrometer regulator, central seconds, automatic winding) and received the serial number 505811, the 18kt yellow gold case received the number 356030.
Osvaldo Patrizzi's article; Louis Cottier; A Watchmaking Genius Ahead of his Time (VOX 2002), identified the world time system used by Patek Philippe, Agassiz, Rolex and Vacheron Constantin was developed by the Geneva watchmaker Louis Cottier (1894 - 1966). Patrizzi declared that Cottier made his first world time pocket watch in 1931 for a local jeweller named Beszanger.
Carlos Perez, in an article; Harmonia Mundi published on TimeZone in 2001, also credited Cottier with a further refinement which mobilized the outer ring of cities and regions.
Contradicting Patrizzi is the book; The World of Vacheron Constantin by Lambelet and Coen, co-published by Vacheron Constantin in 1992, which reveals on page 396 a photograph of Reference 3372 world time watch with a pencilled date notation of 1930. If accurate, this places V&C's watch prior to the piece delivered to Beszanger and therefore Cottier's first. This was first revealed at The Hour Lounge in an earlier post titled; The World Time Watch: Another Vacheron First by Tick Talk (yes, that's me...who else would remember). This story also contained a brief inventory the choices for time zones and how they changed to reflect the political and power centres of their day.
An interesting side story of the Photo Reference 3741 World Time table clocks of 1938 are the base movements; 22-ligne Chronometre Royal calibres from 1914 (photo credit Auktionen Dr. Crott).