Importance of climatic influences--Climate in the interplay of geographic factors--Its direct and indirect effects--Climate determines the habitable area of the earth--Effect of climate upon relief and hence upon man--Man's adaptability to climatic extremes--Temperature as modified by oceans and winds--Rainfall--Temperature and zonal location--Mutual reactions of contrasted zones--Isothermal lines in anthropo-geography--Historical effects of compressed isotherms--Historical effects of slight climatic differences--Their influence upon distribution of immigration--Temperature and race temperament--Complexity of this problem--Monotonous climatic conditions--Effects of Arctic cold--Effect of monotonous heat--The tropics as goals of migration--The problem of acclimatization--Historical importance of the temperate zone--Contrast of the seasons--Duration of the seasons--Effect of long winters and long summers--Zones of culture--Temperate zone as cradle of civilization INDEX LIST OF MAPS. DENSITY OF POPULATION IN THE EASTERN HEMISPHERE 8 DENSITY OF POPULATION IN THE WESTERN HEMISPHERE 9 POWELL'S MAP OF INDIAN LINGUISTIC STOCKS 54 PRIMITIVE INDIAN STOCKS OF SOUTH AMERICA 101 ETHNOGRAPHICAL MAP OF INDIA 102 ETHNOGRAPHICAL MAP OF ASIA 103 ETHNOGRAPHICAL MAP OF AFRICA 105 DISTRIBUTION OF WILD AND CIVILIZED TRIBES IN THE PHILIPPINES 147 DISTRIBUTION OF POPULATION IN THE PROVINCE OF FINMARKEN 153 DISTRIBUTION OF POPULATION IN THE UNITED STATES IN 1800 156 THE SLAV-GERMAN BOUNDARY IN EUROPE 223 ETHNOGRAPHICAL MAP OF RUSSIA 225 THE GERMAN NORTH SEA COAST 243 ANCIENT PHOENICIAN AND GREEK COLONIES 251 RIPARIAN VILLAGES OF THE LOWER ST. LAWRENCE 365 LAKE OF THE FOUR FOREST CANTONS 374 THE ANNUAL RAINFALL OF THE WORLD 484 THE CULTURAL REGIONS OF AFRICA AND ARABIA 487 DISTRIBUTION OF RELIGIONS IN THE OLD WORLD 513 DENSITY OF POPULATION IN ITALY 559 MEAN ANNUAL ISOTHERMS AND HEAT BELTS 612 CHAPTER I THE OPERATION OF GEOGRAPHIC FACTORS IN HISTORY [Sidenote: Man a product of the earth's surface.]