The German chemist Richard Adolf Zsigmondy, 1865-1929. After studying chemistry and physics Zsigmondy joined a glassworks. His interest in coloured glass led him to work on colloids which he continued to do as professor at Gottingen. In 1903 he made an 'ultramicroscope' in which the sample solution is lit from the side. Colloid particles scatter the light and are seen as bright points, even if they are smaller than the resolving power of the microscope. Zsigmondy's pioneer studies on colloids did much to advance the understanding of sols, gels, fogs and foam, and was of great importance in biochemistry. He won the Nobel Prize for chemistry in 1925.