This watch was produced in 1950 and sold on 14 July 1952. It is illustrated in Patek Philippe Wristwatches by Martin Huber & Alan Banbery, 1st edition p. 208 and 2nd edition p. 274.
The split second chronograph in a wristwatch was introduced in the 1920's and was a technical advance over the plain chronograph used more frequently. Its particularity is the additional second hand with separate control button. Already in use as a double timer without the standard time telling, it was used mostly for races whereas doctors often used only the simple stopper.
The features of two overlapping central hands, one of which can be stopped while the other continues to measure, also permitted you to time the total speed over a distance while simultaneously timing the speed over a determined distance.
This particular watch features three rarities in itself: the split second complication, the large size and the black dial.
The looks and functions of watches were influenced by political and fashion events. This watch is unusual for the 1950's, which was a subdued period of recovery in both fashion and politics. The large size, mostly used for Aviator or Airmen watches during the first world war, was hardly used again after 1945 and only relived its fashionability in the late 20th century.
The black dial, a feature very often found in the Art Deco period, was least popular in the 1950's as it was a reminder of death and mourning and again only revived with more prosperity in the 1960's and again in the late 20th Century.