Dial case and movement signed. DIAM. 56 mm. THICKNESS 16 mm. Magnificent & historic unique tourbillon watch - one of the worlds most accurate mechanical precision watches from the early 20th Century & twice observatory first-prize winner in 1929 with a record score of 834 points and again first-prize in 1934. Together with a remarkable comprehensive collection of daily testing records between 1928 and 1952. Provenance Patek Philippe & Cie until June 26th 1939 when sold to a private individual. Bought back in 1942 by Patek Philippe Geneva for its private museum collection (No. 428). By special request of the present owner in 1989 it was decided to sell the watch from the museum. The specially designed 18K gold case was then made to house the movement. Literature The present watch is illustrated and described in "Patek Philippe Geneve" Huber & Banbery 1994 p. 175. The History of Patek Philipe Movement No. 197.895 Patek Philipe tourbillon No. 197895 is a highly important part of the history of mechanical precision timekeeping. The movement was made by Patek Philippe between the years 1927 and 1929 using an ebauche begun in 1924. The steel tourbillon cage made by James Pellaton is fitted with a Guillaume balance to reduce timekeeping errors caused by temperature fluctuation (middle temperature error). The movement had remarkable success at Observatory trial in Geneva and was comprehensively tested for more than 25 years between 1928 and 1958. For the 1929 Geneva Observatory trial the movement was regulated by one of the most famous Patek Philippe "regleurs" or precision timers: François Modoux who set a record of 834 points during that trial with this watch which won First-Prize. This tourbillon again competed in 1934 and once more won First-Prize in its category. The watch continued to excel in various observatory competitions up until 1939 when it was sold to a private individual. Modoux was one of the two regleurs who were responsible for the regulation of most of the watches made by Patek Philippe for the legendary and exacting watch enthusiast Henry Graves Jr. The regleurs were the highest paid workers in the watch industry because success in Observatory trials conferred reputation and prestige on the brand and therefore greater commercial success.