Includes letters (1847-1868) from Helen Rood to her brother Ogden Nicholas Rood and his wife Mathilde concerning family and friends in New Haven, Connecticut; religion; female education; Eli Whitney Blake, whom she married in 1860; her impressions of Heidelberg, where her husband studied; and German and English sentiment concerning the American Civil War. Letters (1859-1891) from Eli Blake to Ogden Rood concerning scientific experiments; his work as professor at Cornell University; and his work at Brown University as professor of physics. Other correspondence includes letters to Eli Blake concerning the National Bell Telephone Company, the University of Virginia, and Troy University.