Thus he enters into a new sort of dependence upon her, because it is only by understanding her capacities and the means of using them that he can get from her what he wants. Primitive man was satisfied if he could find spots where the trees gave edible fruit, where the sun was not too hot, nor the winds too cold, where the beasts easy of capture were abundant, and no tigers or pythons made the forest terrible. Civilised man has more complex problems to deal with, and wider fields to search. The study of Nature is not only still essential to him, but really more essential than ever. His life and action are conditioned by her. His industry and his commerce are directed by her to certain spots. That which she has to give is still, directly or indirectly, the source of strife, and a frequent cause of war. As men fought long ago with flint-headed arrows for a spring of water or a coconut grove, so they fight to-day for mineral treasures imbedded in the soil. It is mainly by Nature that the movements of emigration and the rise of populous centres of industry are determined. Though Nature still rules for many purposes and in many ways the course of human affairs, the respective value of her various gifts changes from age to age, as man’s knowledge and power of turning them to account have changed. The things most prized by primitive man are not those which semi-civilised man chiefly prized, still less are they those most sought for now. [Sidenote: Using Natural Wealth] In primitive times the spots most attractive, because most favourable to human life, were those in which food could be most easily and safely obtained from fruit-bearing trees or by the chase, and where the climate was genial enough to make clothing and shelter needless, at least during the greater part of the year. Later, when the keeping of cattle and tillage had come into use, good pastures and a fertile soil in the valley of a river were the chief sources of material well-being. Wild beasts were less terrible, because man was better armed; but as human enemies were formidable, regions where hills and rocks facilitated defence by furnishing natural strongholds had their advantages.