Papers, 1930-1962, concerning lectures and publications by Hart, notably correspondence, 1951-1961, mainly relating to lectures on Leonardo da Vinci, aeronautical engineering and other subjects; correspondence relating to the writing and publication of his work, including James Watt and the history of steam power (Henry Schuman, New York, [1949]), 1948, and The world of Leonard da Vinci, man of science, engineer and dreamer of flight (Macdonald, London, 1961), 1960-1962; typescripts of lectures on textile education, 1951, the scientific basis for Leonardo da Vinci's work in technology, 1952, and handicraft instruction; typescript of The world of Leonard da Vinci, man of science, engineer and dreamer of flight (Macdonald, London, 1961), 1960; copies of published articles by Hart on medieval and modern science, 1930-1955.