The general physical contour of Africa has been likened to an inverted plate with one or more rows of mountains at the edge and a low coastal belt.  In the south the central plateau is three thousand or more feet above the sea, while in the north it is a little over one thousand feet.  Thus two main divisions of the continent are easily distinguished:  the broad northern rectangle, reaching down as far as the Gulf of Guinea and Cape Guardafui, with seven million square miles; and the peninsula which tapers toward the south, with five million square miles.

Four great rivers and many lesser streams water the continent.  The greatest is the Congo in the center, with its vast curving and endless estuaries; then the Nile, draining the cluster of the Great Lakes and flowing northward “like some grave, mighty thought, threading a dream”; the Niger in the northwest, watering the Sudan below the Sahara; and, finally, the Zambesi, with its greater Niagara in the southeast.  Even these waters leave room for deserts both south and north, but the greater ones are the three million square miles of sand wastes in the north.

More than any other land, Africa lies in the tropics, with a warm, dry climate, save in the central Congo region, where rain at all seasons brings tropical luxuriance.  The flora is rich but not wide in variety, including the gum acacia, ebony, several dye woods, the kola nut, and probably tobacco and millet.  To these many plants have been added in historic times.  The fauna is rich in mammals, and here, too, many from other continents have been widely introduced and used.

Primarily Africa is the Land of the Blacks.  The world has always been familiar with black men, who represent one of the most ancient of human stocks.  Of the ancient world gathered about the Mediterranean, they formed a part and were viewed with no surprise or dislike, because this world saw them come and go and play their part with other men.  Was Clitus the brother-in-law of Alexander the Great less to be honored because he happened to be black?  Was Terence less famous?  The medieval European world, developing under the favorable physical conditions of the north temperate zone, knew the black man chiefly as a legend or occasional curiosity, but still as a fellow man—­an Othello or a Prester John or an Antar.

The modern world, in contrast, knows the Negro chiefly as a bond slave in the West Indies and America.  Add to this the fact that the darker races in other parts of the world have, in the last four centuries, lagged behind the flying and even feverish footsteps of Europe, and we face to-day a widespread assumption throughout the dominant world that color is a mark of inferiority.