"Both temples were built in the time of Tutmosis III., a king of the 18th dynasty, about 1600 years before Christ; but the fortresses in which they stand are of a more ancient date. The foundations of these are granite blocks of Cyclopian dimensions, resting on the rock, and scarcely inferior to the rock itself in durability. They were erected by the first conqueror of the country, King Sesuatesen III., of the 12th dynasty, in order to command the river, so easily done in so narrow a gorge. The immediate successor of this king was Amenemha III., the Moeris of the Greeks: he who accomplished the gigantic work of forming the artificial lake of Moeris, in the Fayoum, and from whose time--the most flourishing of the whole of the old Egyptian kingdom--the risings of the Nile in successive years, doubtless by means of regular markings, as indeed Diodorus tells, remained so well known, that, according to Herodotus, they were recorded in distinct numbers from the time of Moeris. It appears that this provident king, occupied with great schemes for the welfare of his country, considered it of great importance that the rising of the Nile on the most southern border of his kingdom should be observed, and the results forthwith communicated widely in other parts of the land, to prepare the people for the inundations. The gorge at Semne offered greater advantages for this object than any other point; because the river was there securely confined by precipitous rocky cliffs on each side. With the same view he had doubtless caused Nilometers to be fixed at Assuan and other suitable places; for without a comparison with these, the observations at Semne could be of little use. "The highest rise of the Nile in each year at Semne, was registered by a mark, indicating the year of the king's reign, cut in the granite, either on one of the blocks forming the foundation of the fortress, or on the cliff, and particularly on the east or right bank, as best adapted for the purpose. Of these markings eighteen still remain, thirteen of them having been made in the reign of Moeris, and five in the time of his two next successors. These last kings discontinued the observations; for, in the meantime, the irruption of the Asiatic pastoral tribes into Lower Egypt took place, and wellnigh brought the whole kingdom to ruin. The record is almost always in the same terms, short and simple: _Ra en Hapi em renpe_ ... mouth or gate of the Nile in the year.... And then follows the year of the reign, and the name of the king. It is written in a horizontal row of hieroglyphics, included within two lines--the upper line indicating the particular height of the water, as is often specially stated-- [Illustration: sketch of hieroglyphics]