Ditisheim, Paul LaChaux-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 LaChaux-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 LaChaux-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 Edouard Guillaume (1861-1938), future Nobel prize of physic (1920) ("en reconnaissance du service qu'il a 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. 91169, dated August 31, 1920, and No. 98234, 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."