Richard Zsigmondy (1865-1929), Austrian chemist. Zsigmondy's work on colloids won him the Nobel Prize for Chemistry in 1925. Having spent the early part of his career in Vienna, he was appointed Professor and Director of the Institute of Inorganic Chemistry in Gottingen in 1907, where he remained until his retirement. Colloids are mixtures with particular chemical properties, and Zsigmondy's work on their heterogeneous nature by using optical techniques increased the understanding of sols, gels, fogs and foam. This portrait is from the Bain News Service, one of America's oldest news picture agencies, which holds images dating from the 1890s to the 1930s.