The theory of evolution, as set forth by Charles Darwin, Alfred Russel Wallace, Sir Joseph Hooker, and others in the middle of the nineteenth century, has clearly the closest relationship with the geographical theory of the control exercised by environment; it has become, indeed, its fundamental principle. Darwin accompanied the _Beagle_ surveying expedition round the world in 1831–36, and his observations during the voyage qualified him for his life-work. Wallace’s study of the distribution of animals brings at once to the mind his line of demarcation between faunal regions passing through the Malay Archipelago. Hooker was prepared for his interest in plant geography by his voyage with Ross to the Antarctic, by his travels in northern India (1847–51), and other journeys of wide range. Such men were geographers though their fame does not name them so. The application of geographical method is either essential or at least valuable in every branch of natural science; in itself it fulfils functions which the other natural sciences, taken individually, do not, and that is its justification. SHORT BIBLIOGRAPHY OF GEOGRAPHY A general history of geography (mainly, however, concerned with exploration and mapping) is Vivien de Saint-Martin’s _Histoire de la Géographie_ (Paris, 1873); a short historical review dealing more especially with geographical theory will be found in H. Wagner’s _Lehrbuch der Geographie_ (Leipzig, 1900). No English parallels to these works are to be cited, but reference may be made to H. R. Mill’s _International Geography_ (1897) and his article on “Geography” and E. G. Ravenstein’s on “Map” in the _Encyclopædia Britannica_ (eleventh edition). On the earliest period see E. H. Bunbury, _History of Ancient Geography_ (2 vols., London, 1879), and H. F. Tozer, _History of Ancient Geography_ (1897), in the Cambridge Geographical Series; on the “dark age” and down to 1460, C. R. Beazley, _Dawn of Modern Geography_ (3 vols., London, 1897–1906); the sixteenth century is principally covered by the voluminous literature on Columbus, such as Sir C. R. Markham’s _Life of Christopher Columbus_ (London, 1892), E. J. Payne’s _History of the New World called America_ (Vol. I., Oxford, 1892); on the seventeenth and eighteenth centuries, E. Heawood, _Geographical Discovery in the Seventeenth and Eighteenth Centuries_ (Cambridge Geographical Series, 1912). Some of the earlier theoretical works have been cited in the text; a few modern works representative of the various departments of geography may be mentioned here. Those of which the prime purpose is description are represented by E. Reclus’s _La Nouvelle Géographie Universelle_ (19 vols., Paris, 1876–95; there is an English translation) and by _Stanford’s Compendium of Geography and Travel_ (various authors.) F. Ratzel, _Anthropogeographie_ (2 vols., Stuttgart, c. 1891); Ellen C. Semple, _Influences of Geographic Environment_ (London, 1911); E. Suess, _Das Antlitz der