The Book of Dow has an Isabel C. Dowb. 25 Jan 1855; m. Charles M. Cummings. Isabel's parents lived in "the Northfield section" - I assume NH, since her parents were both b. in Croyden NH. The book has details on Isabel's Dow line back through Thomas Dow who lived in Newbury MA in 1639. There is nothing on a marriage date, his family, or any children.