Correspondence, manuscripts of writings, biographical material, research papers, and reprints, relating to the editing of encyclopedia articles on microscopy, spectroscopy, and X-rays; Clark's consultant work for the Delco-Remy Division of General Motors Corporation, General Electric Company, Ohio Oil Company (later Marathon Oil Company), Parker Pen Company, Jos. Schlitz Brewing Company, and the U. S. Army Chemical Corps, Ordnance Corps, and Signal Corps; administration of the University of Illinois and its Analytical Chemistry Division; doctoral candidates and teaching; professional activities; lectures and symposia; crystallography, spectroscopy and X-ray diffraction research. Includes a tape recorded interview with Clark, discussing aircraft metals and rubber research, courses, laboratories, and x-ray studies.
