Professor Siebert has applied to the whole subject a graphic form of illustration which is at the same time a test of his conclusions. How can the scattered reminiscences and records of escapes in widely separated states be shown to refer to the results of one organized method? Plainly by applying them to the actual face of the country, so as to see whether the alleged centres of activity have a geographical connection. The painstaking map of the lines of the Underground Railroad "system" is an historical contribution of a novel kind; and it is impossible to gainsay its evidence, which is expounded in detail in one of the chapters of the book. The result is a gratifying proof of the usefulness of scientific methods in historical investigation; one who lived in an anti-slavery community before the Civil War is fascinated by tracing the hitherto unknown stretches north and south from the centre which he knew. The map bears testimony not only to the wide-spread practice of aiding fugitives, but to the devotion of the conductors on the Underground Railroad. How useful a section of Mr. Siebert's map would have been to the slave-catcher in the 50's, when so many strange negroes were appearing and disappearing in the free states! The facts presented in the brief compass of the map would have been of immense value also to the leaders of the Southern Confederacy in 1861, as a confirmation of their argument that the North would not perform its constitutional duty of returning the fugitives; yet there is no record in this book of the betraying of the secrets of the U. G. R. R. by any person in the service. The moral bond of opposition to the whole slave power kept men at work forwarding fugitives by a road of which they themselves knew but a small portion. The political philosophers who think that the Civil War might have been averted by timely concessions would do well to study this picture of the wide distribution of persons who saw no peace in slavery.