Personal records of Harry L. Welsh, Professor Emeritus of Physics at University of Toronto. Consists of biographical information; certificates and diplomas; addresses; correspondence relating to his employment as chair of the Physics Department and with officials of the Order of Canada; administrative files of the Department of Physics; articles; his retirement, the H. L. Welsh Lectureship in Physics, honors bestowed upon Welsh, and outlines and notes from his four interviews with the Univ. of Toronto Oral History Programme. Includes photographs and posters; one photograph shows Harry Welsh and collegues at sod-turning ceremonies for the Physics Building.