  jerzy witold rÃ³Å¼ycki (; july 24, 1909 in vilshana, near kiev â january 9, 1942 in mediterranean sea, near the balearic islands) was a polish mathematician and cryptologist who worked at breaking german enigma-machine ciphers before and during world war ii. ==life== rÃ³Å¼ycki was born in what is now ukraine, the fourth and youngest child of zygmunt rÃ³Å¼ycki, a pharmacist and graduate of saint petersburg university, and wanda, nÃ©e benita. he attended a polish school in kiev before moving with his family to poland in 1918. in 1926 he completed secondary school at wyszkÃ³w on eastern poland's bug river. rÃ³Å¼ycki studied mathematics 1927â1932 in western poland, at poznaÅ university's mathematics institute, graduating with a master's degree february 19, 1932. he would later earn a second master's degree from poznaÅ university, in geography, on december 13, 1937. in 1929, while still a student, rÃ³Å¼ycki, proficient in german, was one of twenty-odd poznaÅ university mathematics students who accepted an invitation to attend a secret cryptology course organized at a nearby military installation by the polish general staff's cipher bureau, headquartered in warsaw. from september 1932 rÃ³Å¼ycki served as a civilian cryptologist with the polish general staff's cipher bureau, housed till 1937 in warsaw's saxon palace. he worked there together with fellow poznaÅ university mathematics alumni and cipher bureau cryptology-course graduates marian rejewski and henryk zygalski. after rejewski had reconstructed the german military enigma machine in december 1932, rÃ³Å¼ycki and zygalski likewise worked at ongoing development of methods and equipment to exploit enigma decryption as a source of intelligence. rÃ³Å¼ycki invented the "clock" method, which sometimes made it possible to determine which of the machine's rotors was at the far right, that is, in the position where the rotor always revolved at every depression of a key. rÃ³Å¼ycki perished in the mediterranean sea on january 9, 1942, while returning to the cadix center, near uzÃ¨s in southern, vichy france, from a stint at its branch office at the chÃ¢teau couba on the outskirst of algiers. his passenger ship, the lamoriciÃ¨re,the ship had, appropriately, been christened after a 19th-century french general, christophe lÃ©on louis juchault de lamoriciÃ¨re, who had been involved in the french conquest of algeria. sank in unclear circumstances near the balearic islands. fellow victims of the disaster, 
1909_births 1942_deaths 20th-century_Polish_mathematicians Adam_Mickiewicz_University_in_PoznaA_alumni Biuro_SzyfrA3w Polish_cryptographers Pre-computer_cryptographers