There is a fact, however, which ought not to be omitted, as being of some value in the determination of the problem now before us; namely, that the White River begins to swell three or four weeks before the Abyssinian branch receives any accession of water. This may be thought to indicate that the source of the Bahr-el-Abiad must be farther south than the springs which Bruce reached in the meadows of Geesh; for it is well known that the rainy season in every part of the torrid zone accompanies the vertical position of the sun. But from these considerations, perhaps, as also from many others which might be adduced, we ought only to conclude that the most learned geographers are still very much in the dark relative to the origin of the magnificent stream to which Africa owes its chief distinction, as well as in regard to the geological phenomena of that remarkable kingdom from which the civil historian derives his clearest views of the primitive state of the western world. It is an observation as old as the days of Herodotus, that Egypt is the gift of the Nile. This historian imagined that all the lower division of the country was formerly a deep bay or arm of the sea, and that it had been gradually filled up by depositions from the river. He illustrates his rea soning on this subject by supposing that the present appearance of the Red Sea resembles exactly the aspect which Egypt must have exhibited in its original state; and that, if the Nile by any means were admitted to flow into the Arabian Gulf, it would, in the course of twenty thousand years, convey into it such a quantity of earth as would raise its bed to the level of the surrounding coast. I am of opinion, he subjoins, that this might take place even within ten thousand years; why then might not a bay still more spacious than this be choaked up with mud, in the time which passed before our age, by a stream so great and powerful as the Nile ?* The men of science who accompanied the French expedition into Egypt undertook to measure the depth of alluvial matter which has been actually deposited by the river. By sinking pits at different intervals, both on the banks of the current and on the outer edge of the stratum, they ascertained satisfactorily,-first, that the surface of the soil * Euterpe, chap. 11 declines from the margin of the stream towards the foot of the hills; secondly, that the thickness of the deposite is generally about ten feet near the river, and decreases gradually as it recedes from it; and, thirdly, that beneath the mud there is a bed of sand analogous to the substance which has at all times been brought down by the flood of the Nile. This convex form assumed by the surface of the valley is not peculiar to Egypt,-being common to the banks of all great rivers where the quantity of soil transported by the current is greater than that which is washed down by rain from the neighbouring mountains. The plains which skirt the Mississippi and the Ganges present in many parts an example of the same phenomenon. An attempt has likewise been made to ascertain the rate of the annual deposition of alluvial substance, and thereby to measure the elevation which has been conferred upon the valley of Egypt by the action of its river. But on no point are travellers less agreed than in regard to the change of level and the increase of land on the seacoast. Dr. Shaw and M. Savary take their stand on the one side, and are resolutely opposed by Bruce and Volney on the other. Herodotus informs us, that in the reign of Moris, if the Nile rose to the height of eight cubits, all the lands of Egypt were sufficiently watered; but that in his own time,-not quite nine hundred years afterward, the country was not covered with less than fifteen or sixteen cubits of water. The addition of soil, therefore, was equal to seven cubits at the least, or a hundred and twenty-six inches, in the course of nine hundred years. "But at present," says Dr. Shaw, "the river must rise to the height of twenty cubits,-and it usually rises to twenty-four,-before the whole country is overflowed. Since the time, therefore, of Herodotus, Egypt has gained new soil to the depth of two hundred and thirty inches. And if we look back from the reign of Moris to the time of the deluge, and reckon that interval by the same proportion, we shall find that the whole perpendicular accession of the soil, from the deluge to A. D. 1721, must be 500 inches; that is, the land of Egypt has gained 41 feet 8 inches of soil in 4072 years. Thus, in process of time, the whole country may be raised to such a height that the river will not be able to overflow its banks; and Egypt consequently, from being the most fertile, will, for want of the annual inundation, become one of the most barren parts of the universe."* Were it possible to determine the mean rate of accumulation, a species of chronometer would be thereby obtained for measuring the lapse of time which has passed since any monument, or other work of art in the neighbourhood of the river, was originally founded. In applying the principle now stated, it is not necessary to assume any thing more than that the building in question was not placed by its architect under the level of the river at its ordinary inundations, a postulatum which, in regard to palaces, temples, and statues, will be most readily granted. Proceeding on this ground, the French philosophers hazarded a conjecture respecting a number of dates, of which the following are some of the most remarkable. 1. The depth of the soil round the colossal statue of Memnon, at Thebes, gives only 0.106 of a mètre (less than four inches) as the rate of accumulation in a century, while the mean of several observations made in the valley of Lower Egypt gives 0.126 of a mètre, or rather more than four inches. But the basis of the statue of Memnon was certainly raised above the level of the inundation, by being placed on an artificial mound; and excavations made near it show that the original height of that terrace was six mètres (19.686 feet) above the level of the soil. A similar result is obtained from examining the foundations of the palace at Luxor. Taking, therefore, 0.126 of a metre, the mean secular augmentation of the soil, as a divisor, the quotient, 4760, gives the number of years which have elapsed since the foundation of Thebes was laid. This date, which of course can only be considered as a very imperfect approximation to the truth, carries the origin of that celebrated metropolis as far back as 2960 years before Christ, and consequently 612 years before the deluge, according to the reckoning of the modern Jews. But the numbers given there differ materially from those of the Samaritan text and the Septuagint version; which, carrying the deluge back to the year 3716 before Christ, make an interval of seven centuries and a half between the flood and the building of Thebes. Though no distinct account of the age of that * Shaw's Travels, vol. ii. p. 235. city is to be found in the Greek historians, it is clear from Diodorus that they believed it to have been begun in a very remote period of antiquity.* 2. The rubbish collected at the foot of the obelisk of Luxor indicates that it was erected fourteen hundred years before the Christian era. 3. The causeway which crosses the plain of Siout furnishes a similar ground for supposing that it must have been founded twelve hundred years anterior to the same epoch. 4. The pillar of Heliopolis, six miles from Cairo, appears, from evidence strictly analogous, to have been raised about the period just specified; but as the waters drain off more slowly in the Delta than in Upper Egypt, the accumulation of alluvial soil is more rapid there than higher up the stream; the foundations, therefore, of ancient buildings in the former district will be at as great a depth below the surface as those of much greater antiquity are in the middle and upper provinces. But it is obvious that to form these calculations with such accuracy as would render them less liable to dispute, more time and observation would be requisite than could be given by the French in the short period during which they continued in undisturbed possession of Egypt. One general and important consequence, however, arising from their inquiries, can hardly be overlooked or denied; namely, that the dates thus obtained are as remote from the extravagant chronology of the ancient Egyptians, as they are consistent with the testimony of both sacred and profane history, with regard to the early civilization of that interesting country.† But little or no reliance can be placed on such conclusions, because it is now manifestly impossible to ascertain, in the first instance, whether the measures referred to by the ancient historians were in all cases of the same standard; * Diod. Sic. lib. i. c. 15, ἀμφισβητεῖται δ ̓ ἡ κτίσις της πόλεως ταύτης, ου μονον παρα τοις συγγραφευσιν, ἀλλα και παρ ̓ ἀυτοις τοις κατ' Αίγυπτον ἱερεῦσι. † See article "Egypt" in Encyclopædia Metropolitana. The grounds which may be alleged for giving a preference in point of chronology to the Samaritan text, or even to the Septuagint, and the singular approximation to the former, resulting from a mean taken between it, the Hindoo, and the Chinese epochs, are ably stated by Klaproth in his Asia Polyglotta, 25-29. and, secondly, whether the deposition of soil in the Egyptian valley did not proceed more rapidly in early times than it does in our days, or even than it has done ever since its effects first became an object of philosophical curiosity. That the level of the land has been raised, and its extent towards the sea greatly increased since the age of Herodotus, we might safely infer, as well from the great infusion of earthy matter which is held in suspension by the Nile when in a state of flood, as from the analogous operation of all large rivers, both in the old continents and in the new. There is, in truth, no good reason for questioning the fact mentioned by Dr. Shaw, that the mud of Ethiopia has been detected by soundings, at the distance of not less than twenty leagues from the coast of the Delta. Nor is there any substantial ground for apprehending, with the author just named, that, in process of time, the whole country may be raised to such a height that the river will not be able to overflow its banks; and consequently that Egypt, from being the most fertile, will, for want of the annual inundation, become one of the most barren parts of the universe. The fears of the learned traveller might have been removed by the following reflections. As the formation of land in the Delta proceeds at a quicker rate than in the higher parts of the river, the issue of water into the sea becomes, year after year, less rapid, and consequently less copious; the current is retarded by the accumulation of mud; the mouths are successively choked by the increasing masses of sand and soil; and hence, in the course of ages, the stream, creating a barrier against its own escape, is thrown back upon the adjoining valley, and becomes the willing servant of the agriculturist from Rosetta to the Cataracts. The same opinion is expressed by Lucretius in the following verses : Est quoque, uti possit magnus congestus arenæ Cùm mare permotum ventus ruit intus arenam: Quo sit uti pacto liber minus exitus amnis, Et proclivus item fiat minus impetus undis.-Lib vi. v. 724. Then ocean, haply, by the undevious breeze Blown up its channel, heaves with every wave Heaps of high sands, and dams its wonted course. Whence narrower, too, its exit to the main, And with less force the tardy stream descends. |