"One of the most absorbing and interesting of all the recent issues in the department of popular science."--_Chicago Herald_. "Though his subject is a very deep one, his style is so very unaffected and perspicuous that even the unscientific reader can peruse it with intelligence and profit. In reading such a book we are led almost to wonder that so much that is scientific can be put in language so comparatively simple."--_New York Observer_. "The author has seen with his own eyes the most important phenomena of the Ice age on this continent from Maine to Alaska. In the work itself, elementary description is combined with a broad, scientific, and philosophic method, without abandoning for a moment the purely scientific character. Professor Wright has contrived to give the whole a philosophical direction which lends interest and inspiration to it, and which in the chapters on Man and the Glacial Period rises to something like dramatic intensity."--_The Independent_. "... To the great advance that has been made in late years in the accuracy and cheapness of processes of photographic reproduction is due a further signal advantage that Dr. Wright's work possesses over his predecessors'. He has thus been able to illustrate most of the natural phenomena to which he refers by views taken in the field, many of which have been generously loaned by the United States Geological Survey, in some cases from unpublished material; and he has admirably supplemented them by numerous maps and diagrams."--_The Nation_. _MAN AND THE GLACIAL PERIOD_. By G. FREDERICK WRIGHT, D. D., LL. D., author of "The Ice Age in North America," "Logic of Christian Evidences," etc. International Scientific Series. With numerous Illustrations. 12mo. Cloth, $1.75. "It may be described in a word as the best summary of scientific conclusions concerning the question of man's antiquity as affected by his known relations to geological time."--_Philadelphia Press_. "The earlier chapters describing glacial action, and the traces of it in North America--especially the defining of its limits, such as the terminal moraine of the great movement itself--are of great interest and value. The maps and diagrams are of much assistance in enabling the reader to grasp the vast extent of the movement."--_London Spectator_. RICHARD A. PROCTOR'S WORKS. _OTHER WORLDS THAN OURS: The Plurality of Worlds, Studied under the Light of Recent Scientific Researches_. By RICHARD ANTHONY PROCTOR. With Illustrations, some colored. 12mo. Cloth, $1.75.