Patek et Cie. carriage clocks are extremely rare. There are only two other known, they all come from the same 1850?s period, and are in private collections. Furthermore, none of them are numbered. Fortunately, two of them are accompanied by an invoice describing them in detail, enabling us to learn for the first time that Patek et Cie., alongside the production of watches, was also, on rare occasions, involved with clocks.The invoice, which is at the end of a letter to a friend, dated February 4, 1853, describes both clocks in detail. The clocks survived giving us a rare opportunity to date them precisely and to see for the first time examples of Patek?s special clock line.The invoice, which is in Polish - Patek?s mother tongue - describes two carriage clocks, of which one is very similar to the present lot. Patek describes it as 'No 47, pendule portative, striking hours and quarters and repeating by pressing a button, echappement à repos in rubies, enamel dial, case engraved and gilded. With a leather fitted box.' The price was 400 Swiss Francs. The clock resembles the present lot in most of the details, but the escapement. It bears also the signature Patek et Ci.Carriage clocks with chronometer escapements are rare. There were some made for special occasions such as World Exhibitions. For instance, L. Borsendorff, in a report from the 1851 London Exhibition, describes carriage clocks exhibited by Henri Leuba aîne à Bâle (Basel, Switzerland) with a detent escapement. Traditionally, most of the carriage clocks were made in France. Adrien Philippe, who in the 1850?s was already a partner in Patek et Cie., seems to be an advocate of the Swiss carriage clockand was convinced that this part of horological manufacturing would return to Switzerland, as he proclaimed in 1878 in his Etudes sur l?horlogerie à l?Exposition de Paris. Although his beliefs never materialized, the present lot shows that the company, as early as 1850?s, was playing with the idea of making carriage clocks in Switzerland. The clock shows the characteristics of the French roulants, this one being marked H.L. 2424, and the Swiss finish. We believe that the present lot was designeand made by Patek, possibly in collaboration (a common practice) with Henri Leuba, especially for one of the Exhibitions of the 1850?s.Chronograph 'Type XX' and the 'retour en vol' device.Louis Breguet (1880-1955) developed a keen interest in aeronautics, conquering the air in 1907 in his gyroplane, the first helicopter in the world to leave ground with a passenger. Soon afterwards was established the 'Louis Breguet' aircraft industry. Meanwhile, the watchmaking firm Breguet, saw a new opening and began producing watches for pilots or to be fitted on aircrafts. 'Montres Breguet' therefore introduced chronographs with registers and tachometric scale and among their first clients wre, of course, the American Air Force in 1918 and the 'Louis Breguet' aircraft industry in 1922. The number of clients soon increased, especially in the fifties.The chronograph wristwatch 'Type XX', launched in 1954, became the most successful and most famous post-war aviator?s watch. Though at first these watches were intended for the strict use of air forces, Breguet, in the 70?s, launched the second generation of these, edited for civilian use. Breguet?s third generation of 'Type XX Aéronavale' is now on the market.The peculiarity of the 'Type XX' chronograph is that it features the 'retour en vol', or 'instantaneous fly-back' device. This function highly appreciated by pilots and aeronautical authorities, was incorporated in all 'Type XX' models and in chronographs to be fitted in aircraft dashboards. The 'retour en vol' device is a great time saver, reducing three actions to one, since it allows the chronograph hand to return to zero by simply depressing the lower push-button; consequently, the chronograh hand, back at zero, can restart immediately.