Mahogany and brass, keyless-winding, marine Chronometer with 52-hour power reserve (sector at 12 o'clock) and dead seconds electrical contacts. Movement based on 7 Swiss invention patents, delivered to Paul Ditisheim, La Chaux-de-Fonds. Main-plate dial engraved with Grand Prix insignia for Paris in 1900 and Berne in 1914 and the following mentions "Maker to the BritishGovernment, Holder of the Kew and TeddingtonRecords", "Maker to the United States Navy,Record Holder, Neuchatel Observatory, 305 StatePrizes" and "Patented, Swiss Made". Hands adjusted indirectly via a milled wheel to the outside of the bowl. A similar marine Chronometer (No. 137) is illustrated and fully described by Jonathan Betts, in Marine Chronometers at Greenwich, A Catalogue of Marine Chronometers at the National Maritime Museum, Greenwich, Oxford University Press, 2018, pp. 602-604. The author also refers to the work of Rupert T. Gould (1890-1948), The Marine Chronometer. Its History and Development, London, J. D. Potter, 1923, pp. A...-A.... Another marine Chronometer is illustrated and described by Fritz von Osterhausen in Paul Ditisheim, Chronometrier, Neuchâtel, Editions Antoine Simonin, 2003. Similar marine chronometers - No. 196; Antiquorum, Geneva, October 20, 1991, lot 141, sold for the amount of CHF 17 250.- - No. 1 001; Christie's, London, July 2, 2004, lot 29, sold for the amount of GBA£ 14 340.- Ditisheim, Paul La Chaux-de-Fonds, October 28, 1868 - Geneva, February 7, 1945 After early training in Switzerland - at the early age of 13, he entered the Horological School in La Chaux-de-Fonds where he obtained the Diploma of Honour -, he studied in Berlin and Paris, arriving in England in 1891, where he worked as a technician at the Rotherham factory in Coventry. He also worked for several renowned watch manufactures such as his father's, the Fabrique Vulcain of Ditisheim Frères. He started his own manufacture at La Chaux-de-Fonds in 1892, specialising in very high precision watches and jewelled watches. Success in both spheres followed rapidly, and he won many honours for adjusted watches, especially at the Neuchâtel and Kew Observatories. He collaborated with Dr. Charles EdouardGuillaume (1861-1938), future Nobel prize of physic (1920) ("en reconnaissance du service qu'ila rendu en métrologie en découvrant des anomalies dans les aciers de nickel"), in the use of both the Guillaume "integral" balance and the Elinvar-type of auto-compensating balance spring. Circa 1920, Paul Ditisheim designed and patented small bimetallic straps affixed to monometallic balances; a first attempts to produce a "popular" line of pocket chronometers under the "Sovil"trademark (Swiss invention patents No. 91 169, dated August 31, 1920, and No. 98 234, dated August 21, 1921). Solvil, Geneva, was founded early in 1920 to exploit Ditisheim's invention, which offered as an alternative to precision watches fitted with the more expensive Guillaume balances. Paul Ditisheim also contributed many papers to scientific and horological journals, and was associated with Dr. Paul Woog, an oil chemist, in the development of Chronax Watch oils. Paul M. Chamberlain in It's about Time (New York, Richard R. Smith, 1941, pp. 463-467) writes: "M. Paul Ditisheim excelled in every form of watchmaking. He made the smallest watch in the world for the Sultan of Morocco, he designed and executed timepieces of great precision, and exhibited enviable talent as a régleur of his own pieces. He collaborated with Dr. Guillaume in the application of Invar and Elinvar, and produced by their own use and to his own invention of an 'affix', or very small bimetal compensation to the solid balance, a movement which made new records at most of the observatories of the world. A silver cased nineteen jewel, 'up and down' indicator watch, costing sixteen dollars at the factory, sent by me to the Bureau of Standards, took a First Grade Certificate."