Correspondence, diaries, writings, scientific papers, notebooks, notes, and other papers relating primarily to Cottrell's career as a research chemist and scientist. Documents his invention of the electrostatic precipitator, his work while a chemist at the U.S. Dept. of Agriculture, and the founding of Research Corporation. Also includes patent papers for Cottrell's process of producing nitric oxide and material concerning inventions of his associates, Farrington Daniels and P.H. Royster. Includes correspondence with Cottrell's associates and Frank Thomas Cameron, author of Cottrell: Samaritan of Science (1952).