13 APRIL 1918, Page 17

Frontiers : a Study in Political Geography. By C. B.

Fawcett. (Clarendon Press. 3s. net.)—This able and suggestive little book is a good introduction to the study of a most difficult subject. The author inclines to the view that an impassable swamp is as good a natural frontier as any, and that rivers often became boundaries because they flowed through marshy valleys, like the Lower Danube. But swamps become drained and lose their old efficacy as barriers, and the author does not favour the river boundary, though he underrates, we think, the advantage of a definite and permanent dividing-line such as the course of a broad stream provides. Hip closing chapter on " The Evolution of Frontiers " is of great interest, especially for the remarks on the difficulty of rearranging the Western and Southern Slav lands with due regard to racial, economic, and military considerations when " the dominant fact of national distributions is that of intermixture." No perfection of frontiers, he adds, can alone secure peace.