Boundaries: How the Mason-Dixon Line Settled a Family Feud and Divided a Nation

Walker (Secrets of a Civil War Submarine) presents an exhaustively researched account of the people and events surrounding the creation of the Mason-Dixon Line. The author goes back to 16th-century England when the Calvert and Penn families were granted charters for the Maryland and Pennsylvania colonies, respectively. Using the boundary metaphor extensively, the packed-with-facts narrative covers historical, political, religious, geographical, and scientific terrain. The bulk of the story takes readers step by chronological step through Charles Mason’s meticulous astronomical observation work and Jeremiah Dixon’s laborious ground survey in the 1760s as they delineate a boundary that would take on increased significance in the run-up to the Civil War. Thirteen chapters include breakout sidebars that thoroughly contextualize the Mason-Dixon Line, from information on celestial navigation and the Quaker religion to the Fugitive Slave Act of 1850 and sidereal time. Scientific and mathematical concepts are clearly presented and well-defined, but may make for more challenging reading. Archival photos, maps, and diagrams supplement the text, as do extensive source notes, a bibliography, and an index. Ages 10–up. (Mar.)