There were two other canals with sluices at their mouths, from the lake to the river, which were alternately shut and opened when the Nile increased or decreased. This work united every advantage, and supplied the deficiencies of a low inundation, by retaining water which would uselessly have been expended in the sea. It was still more beneficial when the increase of the Nile was too great, by receiving that superfluity which would have prevented seed-time. Were the canal of Joseph cleansed, the ancient mounds repaired, and the sluices restored, this lake might again serve the same purposes. The pyramids described by Herodotus no longer exist, neither are they mentioned by Strabo. When it is considered that this was the work of an individual, and that its object was the advantage and comfort of a numerous people, it must be agreed, with M. Savary, that the king who constructed it performed a far more glorious work than either the Pyramids or the Labyrinth.[e] The Sphinx itself is hardly more distinctly Egyptian than the ruins of Karnak, a solemn memorial of Old Thebes. The famed Egyptologist, Lepsius, visited the region and described the impression the ruins made on him as follows:[a] THE RUINS OF KARNAK The river here divides the broad valley into two unequal parts. On the west side it approaches close to the precipitous Libyan range, which there projects; on the eastern side it bounds a wide fruitful plain, extending as far as Medamut, a spot situated on the border of the Arabian Desert, several hours distant. On this side stood the actual town of Thebes, which seems to have been chiefly grouped round the two great temples of Karnak and Luxor, situated above half an hour apart. Karnak lies more to the north, and farther removed from the Nile; Luxor is now actually washed by the waves of the river, and may even formerly have been the harbour of the city. The west side of the river contained the necropolis of Thebes, and all the temples which stood here referred more or less to the worship of the dead; indeed, all the inhabitants of this part, which was afterwards comprehended by the Greeks under the name of Memnonia, seem to have been principally occupied with the care of the dead and their tombs. The former extent of the Memnonia may be now distinguished by Gurnah and Medinet Habu, places situated at the northern and southern extremities.