We may finally study economic activities and follow their influence in waves, the power and direction of which are affected by racial facts because temperament is no doubt related to physical type, but are more governed by language distributions because difference of language makes such a bar to economic intercourse, at least in early stages. In later stages, with the utilization of coal and steam the international web is woven more closely and more subtly, and this has sadly aggravated the catastrophe due to its rupture by the clumsiness of politicians in the years leading on to 1914. And all through the process of evolution of races, of language and religion and of industry, we may follow the social life of the European peoples and the development of its organization and its expression in response to those processes of evolution. We must see at the same time how it both affects and reflects alterations which are always occurring in the European environment through changes of climate, rising and sinking of the land, clearing of forests and draining of swamps by mankind, development of communications, and other results of the labour of man. {11} 1 '_Races_' Human diversities are deep enough to make the idea of 'European Man' a mere abstraction; we need to think rather of 'European Men' and to study with that broad fact always in mind, realizing that Russians and ourselves are not to be thought of as at different steps on the same ladder, and that the unity which has undoubtedly been trying to grow up in Europe must be a unity-in-diversity with an accompanying growth of education in toleration and breadth of appreciation.