Danysz made considerable advances on the magnetic deflection techniques of Baeyer, Hahn and Meitner, placing the source (he used radium) in a capillary tube under a slit, with a photographic plate in the same horizontal plane. By this means the known number of lines (later understood to be conversion lines) superimposed on the beta energy spectrum of RaB + RaC went from 9 to 27 (later work by Robinson and Rutherford found 64; 16 from RaB and 48 from RaC). He finished his doctoral thesis in 1913, and by 1914 he was considered by Rutherford as a leading researcher into beta decay, but he did no further work. He enlisted in the French army in 1914 and was killed in action near Cormicy.