and history. From these centres emanated the great civic, political, intellectual, artistic, moral, and religious ideas and ideals that still strongly influence the life and faith of the nations that rule the world. The character of each of these early civilizations was in turn largely shaped by the natural environment amidst which it arose.

Egypt's Climate and Resources. The land of the Nile was peculiarly favorable for the development of an exceedingly early civilization. Lying near the equator and between extended areas of hot, dry desert, it possessed an almost perfect climate. While warm, it was never excessively hot, thanks to the fresh north winds which blew from the sea. The desert kept the atmosphere dry and cloudless through at least eleven months in the year. The narrow strip of alluvial soil which constituted the real land of Egypt was practically inexhaustible. The Nile, which rose during the hot summer months, furnished abundant water for irrigation. At the same tune the necessity for constant activity in order to develop the full resources of the land was a valuable incentive to industry. Finally, the uniformity of the Nile valley furnished an excellent basis for a unified social and political organization.

Its Isolation and Limitations. At first Egypt's isolation favored, but in the end fatally impeded the development of its civilization. On every side it was shut in, not only by miles of rocky desert on the east and west, but also on the north and south by almost impassable barriers. In the south the fertile territory narrows to a mere ribbon, with no natural highways by land, while several great cataracts cut off approach by water. On the north the Nile broadens out into a great impassable marsh with only two narrow gateways. One of these is the main western arm of the Nile, which reaches the Mediterranean near Alexandria; the other is the Wady Tumilat, which runs from the Isthmus of Suez through the biblical land of Goshen to the Nile valley. In early centuries these few narrow and uninviting avenues of approach on the north and south were easily guarded. The result was that the Egyptians, at a very early date, attained a high stage of culture, but they lacked that stimulus from without which is essential to the highest development. Once or twice, as in the days of the Hyksos and Ethiopian invasions, foreigners pressed into the land, and as a result the centuries immediately following were the most glorious in Egypt's history. In general, however, the civilization of the Nile valley was deficient in depth and idealism. It was grossly material; it developed too easily and the people were too contented. Even on the artistic side the brilliant promise of the earlier centuries failed of fruition. Moreover, the protecting natural barriers proved constricting, so that there was little opportunity for expansion. Hence Egypt's civilization was always provincial and by 500 B.C. had ceased to develop. From this time on the people of the Nile tamely submitted to the succession of foreign conquerors who have ever since ruled over this garden land of the eastern world.

Conditions in the Tigris-Euphrates Valley. Physical conditions in the Tigris-Euphrates valley were in many ways similar to those along the Nile. A warm but invigorating climate, fertile, alluvial soil, deposited by the great rivers and renewed each year by the floods, and the protection of the desert on the west favored the development of a virile civilization, as early if not earlier than that of Egypt. Starting from the same northern mountains, the two great rivers find their way to the Persian Gulf by widely different courses. The Tigris flows southeast in a comparatively direct course of eleven hundred miles. Its name, "The Arrow," suggests the rapidity of its descent. The Euphrates, on the contrary, makes a long detour westward toward the Mediterranean and then turns to the southeast, where for the greater part of the last half of its one thousand eight hundred miles it flows through the desert. The lands lying between the lower waters of these great rivers were by nature fitted to become the home of the earliest civilization. At a very early period these level plains attracted the nomadic tribes from the neighboring desert. Here they found soil that was exceedingly fertile, but covered to a great extent by the overflow of the great rivers. To be made productive it had to be drained in the flood and irrigated in the dry season by an extensive system of canals and reservoirs. Hence this region furnished powerful incentives to develop an energetic, enterprising civilization. The absence of natural barriers in the level plains of Babylonia and the uniformity of its physical contour meant that in time all the Tigris-Euphrates valley would inevitably be brought under one rule.

Forces Developing Its Civilization. Unlike Egypt, Babylonia was constantly subject to those thrusts from without which were essential to a great civilization. From the Arabian desert came nomadic invaders and from the mountains to the east and north and probably from northern Syria powerful, warlike peoples who either spurred the river dwellers on to strenuous activity in order to repel the hostile attacks or else as conquerors infused new blood and energy into the older races. On the other hand, the absence of constraining barriers gave ample opportunity for natural growth and expansion. The great rivers were the highways of commerce and conquest. The necessity of defence also suggested the advantages of conquest. The result was that at a very early period the armies of Babylonia had penetrated the mountains to the east and north and had carried their victorious rule as far as the shore of the Mediterranean on the west. Traders followed the armies, bearing the products of Babylonian art and in turn enriching the home-land with those of other nations. It was thus that Babylonia in time became not only the mistress of the ancient world, but also one of the chief centres from which emanated political, legal, artistic, and religious ideas and institutions that influenced all the peoples living about the eastern Mediterranean.

Civilization of Arabia. Very different was the site of the third Semitic civilization. The eastern shores of the Red Sea are rocky and barren. No important streams or harbors are found along this cheerless coast. The eastern slope of the range of mountains that runs parallel to the Red Sea is, however, one of the garden lands of the East. The clouds, chilled by the mountains, deposit their rains here, while mountain streams make it possible by irrigation to transform this part of Arabia into a rich agricultural land. Here from an early period was found a high type of civilization. Climate, soil, and the spur of foreign invasion fostered its development. Its products were famous throughout the ancient world. But it was in the highest degree isolated from the stream of the world's progress. Its one means of communication with outside nations was by the caravans which crossed the deserts. Hence a certain halo of mystery always surrounded this distant civilization. Like that of Egypt, it lacked opportunity for expansion and communication and so failed to rise above a certain level or to make any deep or significant impression upon the other Semitic nations.

Physical Characteristics of Syria and Palestine. In marked contrast with Arabia was the strip of hill and mountain country lying on the eastern coast of the Mediterranean, known in later tunes as Syria and Palestine. The dominant feature in this part of the Semitic world was the southern spurs of the Taurus mountains, which here run parallel with the coast in two ranges known as the Lebanons and the Anti-Lebanons. A warm, equable climate and fertile soil, especially in the broad valleys between the mountains, furnish the first necessities for a strong