1865-1929. Austrian chemist who devised and
built an ultramicroscope in 1903. The
microscope's illumination was placed at right
angles to the axis. (In a conventional
microscope the light source is placed
parallel to the instrument's axis.)
Zsigmondy's arrangement made it possible to
observe gold particles with a diameter of
10-millionth of a millimetre. Nobel Prize for
Chemistry 1925.