Its geography and topography.
The extent of surface affected by the inundations of the Nile is, in a geographical point of view, altogether insignificant; yet, such as it was, it constituted Egypt. Commencing at the Cataract of Essouan, at the sacred island of Philæ, on which to this day here and there the solitary palm-tree looks down, it reached to the Mediterranean Sea, from 24° 3´ N. to 31° 37´ N. The river runs in a valley, bounded on one side by the eastern and on the other by the Libyan chain of mountains, and of which the average breadth is about seven miles, the arable land, however, not averaging more than five and a half. At the widest place it is ten and three-quarters, at the narrowest two. The entire surface of irrigated and fertile land in the Delta is 4500 square miles; the arable land of Egypt, 2255 square miles; and in the Fyoom, 340 square miles, an insignificant surface, yet it supported seven millions of people.
Here agriculture was so precise that it might almost be pronounced a mathematical art. The disturbances arising from atmospheric conditions were eliminated, and the variations, as connected with the supply of river-water, ascertained in advance. The priests proclaimed how the flood stood on the Nilometer, and the husbandman made corresponding preparations for a scanty or an abundant harvest.
In such a state of things, it was an obvious step to improve upon the natural conditions by artificial means; dykes, and canals, and flood-gates, with other hydraulic apparatus, would, even in the beginning of society, unavoidably be suggested, that in one locality the water might be detained longer; in another, shut off when there was danger of excess; in another, more abundantly introduced.
Control of agriculture by the government.
There followed, as a consequence of this condition of things, the establishment of a strong government, having a direct control over the agriculture of the state by undertaking and supporting these artificial improvements, and sustaining itself by a tax cheerfully paid, and regulated in amount by the quantity of water supplied from the river to each estate. Such, indeed, was the fundamental political system of the country. The first king of the old empire undertook to turn the river into a new channel he made for it, a task which might seem to demand very able engineering, and actually accomplished it. It is more than five thousand years since Menes lived. There must have preceded his times many centuries, during which knowledge and skill had been increasing, before such a work could even have been contemplated.
Topographical changes occasioned by the Nile.
I shall not indulge in any imaginary description of the manner in which, under such favourable circumstances, the powers of the human mind were developed and civilization arose. In inaccessible security, the inhabitants of this valley were protected on the west by a burning sandy desert, on the east by the Red Sea. Nor shall I say anything more of those remote geological times when the newly-made river first flowed over a rocky and barren desert on its way to the Mediterranean Sea; nor how, in the course of ages, it had by degrees laid down a fertile stratum, embanking itself in the rich soil it had borne from the tropical mountains. Yet it is none the less true that such was the slow construction of Egypt as a habitable country; such were the gradual steps by which it was fitted to become the seat of man. The pulse of its life-giving artery makes but one beat in a year; what, then, are a few hundreds of centuries in such a process?
The inundations lead to the study of astronomy.
The Egyptians had, at an early period, observed that the rising of the Nile coincided with the heliacal rising of Sirius, the Dog-star, and hence they very plausibly referred it to celestial agencies. Men are ever prone to mistake coincidences for causes; and thus it came to pass that the appearance of that star on the horizon at the rising of the sun was not only viewed as the signal, but as the cause of the inundations. Its coming to the desired position might, therefore, be well expected, and it was soon observed that this took place with regularity at periods of about 360 days. This was the first determination of the length of the year. It is worthy of remark, as showing how astronomy and religious rites were in the beginning connected, that the priests of the mysterious temple of Philæ placed before the tomb of Osiris every morning 360 vases of milk, each one commemorating one day, thus showing that the origin of that rite was in those remote ages when it was thought that the year was 360 days long. It was doubtless such circumstances that led the Egyptians to the cultivation of historical habits. In this they differed from the Hindus, who kept no records.