Asistent Fyzikálního ústavu Německé univerzity v Praze v letech 1906–1914 se „slibným“ jménem Weiss a měření elementárního elektrického náboje

This study is dedicated to the Austrian physicist Edmund Weiss (1884–1932) and his time as assistant at the Institute of Physics of the German University in Prague in 1906–1914. Particular attention is paid to his 1911 habilitation work on the elementary quantum of electricity, which he measured in experiments with ultramicroscopic silver particles. In this work, Weiss repeated the measurements of Vienna physicist Felix Ehrenhaft. Unlike he, Weiss managed to confirm – with the help of Einstein’s 1905 formula for Brownian molecular motion – the value of elementary quantum of electricity, which had first been established by R. A. Millikan in his ‘oil drop’ experiments. Albert Einstein, at that time (in 1911–1912) professor of theoretical physics at the German University in Prague, praised Edmund Weiss and his work at the First Solvay Conference on Physics in Brussels in autumn 1911. Details of Weiss’s habilitation work at the Institute of Physics in Prague were described in letters written by Anton Lampa, professor and director of the institute, and addressed to the doyen of Viennese physics Viktor von Lang. Full texts of six of Lampa’s letters (in German) are appended to the study.