which could have contained a basin measuring at least ninety miles in circumference? Linant supposed "Lake Moeris" to have extended over the whole of the low-lying land which skirts the Libyan cliffs between Illahûn and Medinet el Fayûm; but recent explorations have proved that the dikes by which this pretended reservoir was bounded are modern works, erected probably within the last two hundred years. Major Brown has lately shown that the nucleus of "Lake Moeris" was the Birket el Kûrûn.[8] This was known to the Egyptians as _Miri, Mi-ûri,_ the Great Lake, whence the Greeks derived their _Moiris_ a name extended also to the inundation of the Fayûm. If Herodotus did actually visit this province, it was probably in summer, at the time of the high Nile, when the whole district presents the appearance of an inland sea. What he took for the shores of this lake were the embankments which divided it into basins and acted as highways between the various towns. His narrative, repeated by the classic authors, has been accepted by the moderns; and Egypt, neither accepting nor rejecting it, was gratified long after date with the reputation of a gigantic work which would in truth have been the glory of her civil engineers, if it had ever existed. I do not believe that "Lake Moeris" ever did exist. The only works of the kind which the Egyptians undertook were much less pretentious. These consist of stone-built dams erected at the mouths of many of those lateral ravines, or wadys, which lead down from the mountain ranges into the valley of the Nile. One of the most important among them was pointed out, in 1885, by Dr. Schweinfurth, at a distance of about six miles and a half from the Baths of Helwan, at the mouth of the Wady Gerraweh (fig. 47). It answered two purposes, firstly, as a means of storing the water of the inundation for the use of the workmen in the neighbouring quarries; and, secondly, as a barrier to break the force of the torrents which rush down from the desert after the heavy rains of springtime and winter. The ravine measures about 240 feet in width, the sides being on an average from 40 to 50 feet in height. The dam, which is 143 feet in thickness, consists of three layers of material; at the bottom, a bed of clay and rubble; next, a piled mass of limestone blocks (A); lastly, a wall of cut stone built in retreating stages, like an enormous flight of steps (B). Thirty-two of the original thirty-five stages are yet _in situ_, and about one-fourth part of the dam remains piled up against the sides of the ravine to right and left; but the middle part has been swept away by the force of the torrent (fig. 48). A similar dike transformed the end of Wady Genneh into a little lake which supplied the Sinaitic miners with water.