Includes diaries (50 v., 1866-1913) describing Blake's service as draftsman with the U. S. Coast Survey (1866-1875) and astronomer with Darien Exploring Expedition (1870), and his experiments in physics and electrical communication which led to the development of the transmitter for Bell Telephone Company; together with correspondence relating to Blake's association with American Academy of Arts and Sciences, American Institute of Electrical Engineers, Harvard University, Massachusetts General Hosptial, Massachusetts Horticultural Society, Massachusetts Institute of Technology, Thursday Evening Club; and Town of Weston, Mass.; records of household expenses and business investments; 150 printed volumes relating to Blake's research; diaries (5 v., 1885-1905) of Blake's wife, Elizabeth (Hubbard) Blake; and sketch (1879) by Alexander Graham Bell.