With colour copy of the Observatoire National de Besançon First Class Bulletin de Marche No. 21'853 confirming that the bracelet chronometètre with lever escapement, steel spring, Guillaume balance and a movement diameter of 13 lines, participated at the First Class Timing Contest Category C where it obtained 80.56 points. It was deposed on 4 October 1949 under the observatory number 54 by Mr. Pelot for the firm Leroy domiciled in Paris and regulated by the precision adjuster Mr. Pelot of Besançon.
According to the Archives of Montres Breguet, the present watch with Leroy calibre 13''' movement, platinum case, "old Breguet-style" engine-turned silvered dial with gold hands, was sold in 1952 to Monsieur Gay. The selling price is not stated but must have been important considering that the watch was awarded a First Class Rating Certificate from the Besançon Observatory in 1952 as confirmed by the Archives.
The present watch is part of an exceedingly small series of only a handful of such wristwatches fitted with Observatory movements made by Breguet in the 1950s, mostly cased in gold, including one sold to Mr. Givenchy. This watch is however believed to be the only example featuring a platinum case.
The movement was supplied by the celebrated Louis Leroy, Horloger de la Marine, whose watches participated in various exhibitions and were awarded numerous prizes, particularly at chronometer contests. It is stamped with Leroy's serial number 21'853 and with the "Viper's Head", the symbol used by the Besançon Observatory for movements which had successfully passed the chronometer trial.
Consigned by a descendant of the original owner, the present watch is further distinguished by its excellent, original overall condition. Evidently only seldom been used, the case has preserved its proportions to the best extent, most notably are the sharp edges to the substantial lugs and clear hallmark to the side. The dial has naturally aged and does not show any signs of restoration.
The present watch and its combination of rarity, condition and private provenance must be counted amongst the most important collector's wristwatches of Breguet's 20th century production.
Observatory contests were the ultimate tests in high precision watchmaking or chronometry. The testing process lasted typically 45 days, a movement was tested in 5 positions and 2 temperatures, in 10 series of 4 or 5 days each. The tolerances for error were much stricter than any other standard, including the modern standard. Movements which passed the stringent tests were called Observatory Chronometer and issued a Bulletin de Marche or Rating Certificate, stating the testing criteria and the actual performance.