with his student Eduard Haschek to develop a method for rapid measurement of wavelengths by using enlarged photo-plates and spectral projections onto a white screen. During his final decades his personal research work was primarily concerned with the implications of the Young–Helmholtz "three colo(u)r" theory, attempting to ground the theory more firmly in experimental evidence, and defending it robustly against detractors. Franz Serafin Exner was viewed by admirers, including his students, as a versatile and exceptionally broadly educated physicist with a strong vision, cultivating versatile and highly educated pupils. He was a pioneer in numerous areas of modern physics, greatly broadening the accepted scope of the subject through his endeavours. The early introduction to university curricula of subjects such as radioactivity, spectroscopy, electrochemistry (galvanic element), electricity in the atmosphere, and color theory in Austria can all be credited to him. His most famous pupils included Marian Smoluchowski, a Viennese physicist of Polish descent, who discovered a theory of for Brownian motion independently of Albert Einstein and Friedrich Hasenöhrl. Erwin Schrödinger, who later also won a Nobel prize, also began his remarkable career as Exner's pupil, later becoming his research assistant in 1911. In 1914, Schrödinger received his Habilitation (higher postgraduate degree) with his "Studies on the kinetics of dielectrics, melting point, pyro- and piezoelectricity". Exner supervised the habilitation. One of Exner's doctoral students was Stefan Meyer, who beame the first director of the Institute for Radium Research ("Institut für Radiumforschung"), itself the first university institute in the world dedicated to researching radioactivity, and opened in 1910 in Vienna by Exner himself. Lise Meitner, credited with several important discoveries including, in 1917, that of the radioactive isotope protactinium-231, was another of Exner's doctoral students. During the 1920s and 1930s a remarkable preponderence of university chairs in Physics in the German speaking world were occupied by Exner's former students: , Brno, later full professor in Prague; , Prague; Hans Benndorf, Graz; Marian Smoluchowski, Czernowitz, Krakau; Stefan Meyer, Vienna; Egon Schweidler, Innsbruck, Vienna; , extra full professor Vienna; Friedrich Hasenöhrl, Vienna; , Heinrich Mache, Vienna; Victor Conrad, Brünn, later USA; Felix Maria von Exner-Ewarten, Vienna; , Innsbruck; , Vienna; Felix Ehrenhaft, Vienna; , Brünn; Wilhelm Schmidt, Vienna; , Vienna; Victor Francis Hess, Graz, Innsbruck, New York; , Graz; Ludwig Flamm, Vienna; Erwin Schrödinger, Jena, Leipzig, Zurich, Berlin, Graz, Dublin, Vienna; and Hans Thirring, Vienna. Selected publications Franz Exner und Sigmund Exner: Die physikalischen