Thirdly, the progress of the sciences of Nature has powerfully influenced history, both by providing new data and by affecting the mental attitude of all reflective men. This has happened in several ways. Geographical exploration has made known nearly every part of the surface of the habitable globe. The great natural features of every country, its mountain ranges and rivers, its forest or deserts, have been ascertained. Its flora and fauna have been described, and thereby its capacity for supporting human life approximately calculated. The other physical conditions which govern the development of man, such as temperature, rainfall, and the direction of prevalent winds have been examined. Thus we have acquired a treasury of facts relating to the causes and conditions which help the growth of civilisation and mould it into diverse forms, conditions whose importance I shall presently discuss in considering the relation of man to his natural environment. Although a few penetrating minds had long ago seen how much the career of each nation must have been affected by physical phenomena, it is only in the last two generations that men have begun to study these phenomena in their relation to history, and to appreciate their influence in the formation of national types and in determining the movement of races over the earth’s surface. Not less remarkable has been the increase in our knowledge of the more remote and backward peoples. Nearly every one of these has now been visited by scientific travellers or missionaries, its language written down, its customs and religious rites, sometimes its folk lore also, recorded. Thus materials of the highest value have been secured, not only for completing our knowledge of mankind as a whole, but for comprehending in the early history of the now highly civilised peoples various facts which had previously remained obscure, but which became intelligible when compared with similar facts that can be studied in their actuality among tribes whom we find in the same stage to-day as were the ancestors of the civilised nations many centuries ago. [Sidenote: Progress of the Sciences]