Early price lists and bound volumes of the Company's catalogs (1882-1953); many manufacturing drawings, assembly drawings, instrument data cards, operating instructions and repair manuals for the Company's products (1890-1970); two press-copy personal letter-books (ca. 1877-1883) and a technical notebook (ca. 1873-1890) belonging to Horace Darwin. Four Company press-copy letter-books, one sales order book and two cash books (1880s); Articles of Association of the Company (1895); directors' agenda book (1895-1906); and Annual Reports (ca. 1895-1917). There are approximately 10,000 photographic negatives with album prints covering instruments manufactured from 1900 to 1970. Early minute books of the Social Club and the Employees' Benefit Fund; a large collection of miscellaneous documents, including agreements, patents, memoranda and letters (ca. 1890-1970); and copies of board minutes, accounts, etc. for the American associate company.