Swiss gold lever World Time dress watch with long chain Circa 1964

Gold keyless lever World Time watch by Patek Philippe
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A very fine and very rare Swiss 18 carat yellow gold keyless lever World Time dress watch with a long 18 carat yellow gold chain, circa 1964. Sold on September 3rd, 1964. Rhodium-plated movement, Geneva striping decoration, 18 jewels, straight-line lever escapement, cut bimetallic compensation balance adjusted to heat, cold, isochronism and five positions, blued steel Breguet balance spring with swan-neck micrometre regulator. Silver dial with applied yellow gold baton hour indexes, outer Arabic dark and light revolving chapter ring for the day and night hours and the world time chapter ring, bearing the name of 41 locations around the world and revolving with the bezel according to the Louis Cottier world time patent and yellow gold halberd & dauphine hands. Solid case, polished with brushed back and milled revolving bezel. Dial, case and movement signed, case and movement numbered. Accompanied by the original fitted box and the Extract from the Archives.
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Diameter: 44.5 mm
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Signed: Patek Philippe Genève
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Patek Philippe ‘World Timers’. This system was invented circa 1935 by Louis Cottier (1894-1966), a famous independent watchmaker in Geneva. This system was used by Patek Philippe and also by other major names in the Swiss watch industry, such as Agassiz, Rolex and Vacheron Constantin.
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The halberd hour hand of this piece is the type usually only found on the Reference 605 with cloisonné dial. Reference 605 HU (Heures Universelles) was produced between the 1940s and 1960s and is a series of dress watches bearing the names of approximately 30 to 41 cities in the world on the revolving bezel. Some examples have a matte silvered dial or black dial, others have a cloisonné enamel dial. They were made as follows: in rose gold, with silvered guilloché dial – in rose gold, with translucent enamel dial – in rose gold, with cloisonné enamel dial representing various continents – in yellow gold, with silvered guilloché dial – in yellow gold, with translucent enamel dial – in yellow gold, with cloisonné enamel dial representing various continents. One example is known to date in white gold, with a cloisonné enamel dial representing various continents