comparatively easy for Maryland and Virginia to co-operate with Pennsylvania. In so far, indeed, as population had extended back from the tide-water districts into the hill country and the Appalachian valleys, the settlement both of Maryland and Virginia had proceeded very largely from Pennsylvania.
Thus the Middle States had a great mission to perform in uniting and holding together the more extreme sections. In the development, after the Revolutionary War, of the country west of the Alleghanies, this harmonizing influence of the Middle States was very conspicuously shown in the creation of the great commonwealth of Ohio, and only to a less degree in the making of a number of other States in what has now come to be called the Middle West—the region that produced men of the type of Lincoln and Grant, and that joined with the old Middle States in later crises to preserve the Union and fuse its elements into a homogeneous nation.
No communities in the world lend themselves more profitably to the study of history than these which are described in the present volume. Concrete illustration aids no less in the study of history than in that of the physical
