The study of history is always, from one standpoint, a study of progress. Yet after all the century-long investigation of the history of every people working out its destiny in its given environment, struggling against the difficulties of its habitat, progressing when it overcame them and retrograding when it failed, advancing when it made the most of its opportunities and declining when it made less or succumbed to an invader armed with better economic or political methods to exploit the land, it is amazing how little the land, in which all activities finally root, has been taken into account in the discussion of progress. Nevertheless, for a theory of progress it offers a solid basis. From the standpoint of the land social and political organizations, in successive stages of development, embrace ever increasing areas, and make them support ever denser populations; and in this concentration of population and intensification of economic development they assume ever higher forms. It does not suffice that a people, in order to progress, should extend and multiply only its local relations to its land. This would eventuate in arrested development, such as Japan showed at the time of Perry's visit. The ideal basis of progress is the expansion of the world relations of a people, the extension of its field of activity and sphere of influence far beyond the limits of its own territory, by which it exchanges commodities and ideas with various countries of the world. Universal history shows us that, as the geographical horizon of the known world has widened from gray antiquity to the present, societies and states have expanded their territorial and economic scope; that they have grown not only in the number of their square miles and in the geographical range of their international intercourse, but in national efficiency, power, and permanence, and especially in that intellectual force which feeds upon the nutritious food of wide comparisons. Every great movement which has widened the geographical outlook of a people, such as the Crusades in the Middle Ages, or the colonization of the Americas, has applied an intellectual and economic stimulus. The expanding field of advancing history has therefore been an essential concomitant and at the same time a driving force in the progress of every people and of the world. [Sidenote: Man's increasing dependence upon nature.]