David B. Clark Ronald E. Thompson David B. Clark is associate professor of chemistry at The Williamsport Area Community College, 1005 W. Third St., Williamsport, PA 17701, where he has taught since 1966. He has a B.A. in chemistry from Lycoming College and a M.S. in chemistry from Bucknell University. He is interested in and has taught certain aspects of environmental science, particularly in the areas of atmosphere and air pollution, radiation and radioactivity, and nuclear energy. Clark plans to teach an introductory astronomy course and is interested in the origin and evolution of elementary particles. Ronald E. Thompson is a professor of biology at The Williamsport Area Community College, where he has taught general biology, anatomy and physiology, and ecology since 1965. He has a B.S. in biology from Lycoming College and a M.S. in biology from Emporia State University. The co-author of Experimental Designs for the General Biology Laboratory, Thompson is particularly interested in the study and research of aquatic ecology.