Papers of Professor Harold Heywood, 1925-1973, comprising biographical papers; notebooks and papers, 1925-1957, covering Heywood's undergraduate career at Imperial College, work concerning dusts and sedimentation, sieving, particle size and pulverisation, including records of work undertaken during World War Two and after for the Ministry of Supply concerning the problems caused by dust during military operations in desert warfare, travel diaries; working papers on particles and pulverisation, 1929-1971; working papers on solar energy, 1946-1970, begun at Imperial College but mainly carried on at Woolwich and Loughborough, including notes and observations, travel diaries, correspondence and other papers relating to conferences and consultancies relating to solar energy; lectures and papers, 1924-1971; correspondence, 1933-1958; reports and publications, 1937-1948.