Ref. 1416 Only three examples of this watch are known to exist and they are characterised by the use of straight "claw" lugs. A similar watch is published in Patch Philippe Wristwatches by Martin Huber & Alan Banbery Edition 1998 p. 244. Patek Philippe "World Timers" The "World Time" system was invented around 1935 by Louis Cottier (1894-1966) famous independent watchmaker in Geneva. This "World Time" system was used by Patek Philippe and also by other major names in the Swiss watch industry such as Agassiz Rolex and Uacheron Constantin. Patek Philippe created various series of "World Timers" and the earliest known is a probably unique rectangular "galbe" pink gold model Ref. 515 made in 1937 which was sold by Antiquorum Geneva April 10 1994 lot 502 for SFr. 550000 (US$ 388560) . From 1937 until about 1940 Patek Philippe used the "World Time" movement in various types of cases: Ref. 542 (0 28 mm.) of which only 4 examples are known to date and three were sold byAntiquorun: - Geneva October 17 1993 lot 431 at SFr. 121000 (US$ 81700) - Geneva October 15-16 1994 lot 608 at SFr. 110000 (US$ 87300) - Geneva April 10 1994 lot 500 at SFr. 231000 (US$ 164200) with unusual bezel and hands. Ref. 96 "Calatrava" which appears to be an unique example made in 1939. Around 1939-1940 began the production of the series Ref. 1415 (drop-shaped lugs) together with three examples of the Ref. 1416 (straight "claw" lugs) both references with a diameter of 31 mm. and on the revolving bezel the names of 30 cities of the world. hs 1940 Patek Philippe created specially for Dr. P. Schmidt a unique "World Time" chronograph ( Ref. 1415-1) wristwatch in yellow gold with square push buttons and the names of 33 cities of the world which was auctioned by Antiquorum Geneva October 15-16 1994 lot 516 setting a World Record at SFr. 990000 (US$ 785714). This watch is illustrated on the front cover and p. 270 of the new edition (1998) of Pack Philippe Geneve Wristwatches by Martin Huber & Alan Banbery. From 1940 onwards Patek Philippe produced "World Timers" in three main series which include chess watches (Ref. 605 circa 1940- 1960s) some with a matt silvered dial and others with a cloisonne enamel dial; and wristwatches with one crown (Ref. 1415 circa 1939-1950s) and two crowns (Ref. 2523 and Ref. 2523-1 circa 1953-1965) some with a matt silvered or gilt dial some with a guilloche dial some with an enamel dial and some with a "cloisonne" enamel dial. "World Time" Patek Philippe mismatches are published in Patek Philippe Geneve Wristwatches by Martin Huber & Alan Banbery. 1998 Edition pp. 240 to 247.