The Harry Farnsworth Brown (1886-1980) papers consist almost entirely of personal letters sent to Brown between the years 1901 and 1905. Most are from his father, Harry B. Brown, secretary of the McLagon Foundry Company in New Haven, his mother, his sister Grace, and his uncle Charles S. Brown, professor of mechanical engineering at Vanderbilt University. Most are family-oriented, but they show Brown's early interest in electrical technologies. One letter from his parents describes their impressions of the Pan American Exposition in Buffalo, particularly the effect of the electric illumination. Many were written to Brown when he was in St. Louis in 1904, apparently attached to the Connecticut Building at the Louisiana Purchase Exposition. The later items are mostly Christmas cards and routine letters from foreign colleagues in electrical engineering, some in Spanish.

There are nine snapshot photographs, most of which appear to be of the McLagon Foundry Company, on Audubon Street in New Haven, Connecticut.