There are, however, in fact, three interruptions to the continuity of this plain, though only one of them constitutes any considerable interruption to its barrenness. They are all of them valleys, extending from north to south, and lying side by side. The most easterly of these valleys is so deep that the waters of the ocean flow into it from the south, forming a long and narrow inlet called the Red Sea. As this inlet communicates freely with the ocean, it is always nearly of the same level, and as the evaporation from it is not sufficient to produce rain, it does not even fertilize its own shores. Its presence varies the dreary scenery of the landscape, it is true, by giving us surging waters to look upon instead of driving sands; but this is all. With the exception of the spectacle of an English steamer passing, at weary intervals, over its dreary expanse, and some moldering remains of ancient cities on its eastern shore, it affords scarcely any indications of life. It does very little, therefore, to relieve the monotonous aspect of solitude and desolation which reigns over the region into which it has intruded. The most westerly of the three valleys to which we have alluded is only a slight depression of the surface of the land marked by a line of _oases_. The depression is not sufficient to admit the waters of the Mediterranean, nor are there any rains over any portion of the valley which it forms sufficient to make it the bed of a stream. Springs issue, however, here and there, in several places, from the ground, and, percolating through the sands along the valley, give fertility to little dells, long and narrow, which, by the contrast that they form with the surrounding desolation, seem to the traveler to possess the verdure and beauty of Paradise. There is a line of these oases extending along this westerly depression, and some of them are of considerable extent. The oasis of Siweh, on which stood the far-famed temple of Jupiter Ammon, was many miles in extent, and was said to have contained in ancient times a population of eight thousand souls. Thus, while the most easterly of the three valleys which we have named was sunk so low as to admit the ocean to flow freely into it, the most westerly was so slightly depressed that it gained only a circumscribed and limited fertility through the springs, which, in the lowest portions of it, oozed from the ground. The third valley--the central one--remains now to be described.