The most easterly of the channels by which the waters of the river find their way through the Delta to the sea, is called, as it will be seen marked upon the map, the Pelusiac branch. It forms almost the boundary of the fertile region of the Delta on the eastern side. There was an ancient city named Pelusium near the mouth of it. This was, of course, the first Egyptian city reached by those who arrived by land from the eastward, traveling along the shores of the Mediterranean Sea. On account of its thus marking the eastern frontier of the country, it became a point of great importance, and is often mentioned in the histories of ancient times. The westernmost mouth of the Nile, on the other hand, was called the Canopic mouth. The distance along the coast from the Canopic mouth to Pelusium was about a hundred miles. The outline of the coast was formerly, as it still continues to be, very irregular, and the water shallow. Extended banks of sand protruded into the sea, and the sea itself, as if in retaliation, formed innumerable creeks, and inlets, and lagoons in the land. Along this irregular and uncertain boundary the waters of the Nile and the surges of the Mediterranean kept up an eternal war, with energies so nearly equal, that now, after the lapse of eighteen hundred years since the state of the contest began to be recorded, neither side has been found to have gained any perceptible advantage over the other. The river brings the sands down, and the sea drives them incessantly back, keeping the whole line of the shore in such a condition as to make it extremely dangerous and difficult of access to man. It will be obvious, from this description of the valley of the Nile, that it formed a country which was in ancient times isolated and secluded, in a very striking manner, from all the rest of the world. It was wholly shut in by deserts, on every side, by land; and the shoals, and sand-bars, and other dangers of navigation which marked the line of the coast, seemed to forbid approach by sea. Here it remained for many ages, under the rule of its own native ancient kings. Its population was peaceful and industrious. Its scholars were famed throughout the world for their learning, their science, and their philosophy.