In preparing for the press an Italian translation of this work, published at Florence in 1870, I made numerous corrections in the statement of both facts and opinions; I incorporated into the text and introduced in notes a large amount of new data and other illustrative matter; I attempted to improve the method by differently arranging many of the minor subdivisions of the chapters; and I suppressed a few passages which teemed to me superfluous. In the present edition, which is based on the Italian translation, I have made many further corrections and changes of arrangement of the original matter; I have rewritten a considerable portion of the work, and have made, in the text and in notes, numerous and important additions, founded partly on observations of my own, partly on those of other students of Physical Geography, and though my general conclusions remain substantially the same as those I first announced, yet I think I may claim to have given greater completeness and a more consequent and logical form to the whole argument Since the publication of the original edition, Mr. Elisee Reclus, in the second volume of his admirable work, La Terre (Paris, 1868), lately made accessible to English-reading students, has treated, in a general way, the subject I have undertaken to discuss. He has, however, occupied himself with the conservative and restorative, rather than with the destructive, effects of human industry, and he has drawn an attractive and encouraging picture of the ameliorating influences of the action of man, and of the compensations by which he, consciously or unconsciously, makes amends for the deterioration which he has produced in the medium he inhabits. The labors of Mr. Reclus, therefore, though aiming at a much higher and wider scope than I have had in view, are, in this particular point, a complement to my own. I earnestly recommend the work of this able writer to the attention of my readers. George P. Marsh Rome, May 1, 1878. BIBLIOGRAPHICAL LIST OF WORKS CONSULTED IN THE PREPARATION OF THIS VOLUME. Amersfoordt, J.P. Het Haarlemmermeer, Oorsprong, Geschiedenis, Droogmaking. Haarlem, 1857. 8vo. Andresen, C.C. Om Klitformationen og Klittens Behandling og Bestyrelse. Kjobenhavn, 1861. 8vo. Annali di Agricoltura, Industria e Commercio. Pubblicati per cura del Ministero d'Agricoltura, Industria e Commercio. Faso i-v. Torino, 1862-'3. 8vo. Arago, F. Extracts from, in Becquerel, Des Climate. Arriani, Opera. Lipsiae, 1856. 2 vols. 12mo. Asbjornen, P.Chr. Om Skoveno og om et ordnet Skovbrug i Norge. Christiania, 1855. 12mo. Aus der Natur. Die neuesten Entdeckungen auf dem Gebiete der Naturwissenschaften. Leipzig, various years. 20 vols. 8vo. Ave-Lallemant, K.C.B. Die Benutzung der Palmen am Amazonenstrom in der Oekonomie der Indier. Hamburg, 1861. 18mo. Babinet. Etudes et Lectures sur les Sciences d'Obsorvation. Paris, 1855- 1863. 7 vols. 18mo. Baer, von. Kaspische Studien. St. Petersburg, 1855-1859. 8vo.