Chiefly records of two directors of Blue Hill Meteorological Observatory: A. Lawrence Rotch and Charles F. Brooks. Rotch's records contain incoming letters from scientists at other observatories, such as Kew in England, Mt. Kosciusko in Australia, and the Institute of Meteorology in Nanking, China. Subjects relate to kite meteorology, cloud measurement, balloons (including ascents from Berlin, 1891 and Strassburg, 1901) and balloon construction, observations of auroral bands, etc., as well as events, such as exhibitions of scientific instruments and meteorological congresses. Notable correspondents include Octave Chanute and W. H. Dines. Also photographs, reprints, and documents concerning the Dines pressure tube anemometer. A considerable number of photographs, ca.1890s-1900s, show activities and staff at the Blue Hill Observatory and include interior and exterior views of the station and of instruments such as electrometers. Other photos from this period are of foreign weather observatories and equipment; the first balloon ascent in the U.S. (1904); cloud formations and phenomena such as lightning; and general views taken from kites. Additional Rotch records include typescripts of his writings on the use of kites for weather observations; notes on the International Congress of Hydrology and Climatology (1889) and on balloon ascents in Paris that year; letters and other papers about the New England Meteorological Society and its 1889 exhibit.

Records of Brooks include some correspondence, ca.1930-ca.1940, mostly pertaining to radiosonde; manuscripts of writings; and news releases. Other reference materials in the collection are a large number of reprints of scientific articles, many by Harvard faculty; Blue Hill publications and reports; weather charts and graphs; equipment catalogues from Zeiss, Husun, Wild, and other companies; and books. Topics covered in these sources include kites and aeronautics, atmosphere, wind, temperature, eclipses and aurora borealis, radiant energy, thunder, storms, magnetism, and climate. There is also an automatic aerial camera (a special order by Rotch from a French firm in 1899) which is housed in the Historical Scientific Instruments Collection as well.