864 NOETH-EAST AFRICA. when their farther progress was arrested by an oracle which declared that they were being executed " for the benefit of a barbarian." And it was, in fact, a foreigner. King Darius of Persia, who opened the com- munication between the Nile and the Gulf of Arsinoe, consequently between the Mediterranean and Red Sea, by a well-constructed canal, wide enough, says Herodotus, to allow two triremes to pass each other in mid-stream. According to Diodorus Siculus, the same king even entertained the idea of cutting a canal from sea to sea, between the Gulf of Pelusium and the Red Sea. The works seem to have even been begun, for the banks, some 16 feet high, are still to be seen of a ditch from 160 to 180 or 200 feet wide, running from Lake Timsah by the Gisr towards El-Kantara. But it was feared that the " waters of the Red Sea, standing at a higher level than the plains of Egypt," would flood all the land, and for this reason the works were discontinued. Monuments bearing inscriptions in four languages — Persian, Medo-Scythian, Assyrian, and Egyptian — were erected on the banks of the canal near Suez. These inscriptions record the fruitless attempts made by Darius to accomplish the work successfully carried out in our days. The fear entertained by the Persian monarch — a fear still shared by most engineers down to the middle of the nineteenth century — is all the more easily understood when it is considered that the mean level of the southern waters does in fact exceed that of the Mediterranean at Pelusium. At ebb there is scarcely any perceptible difference, but at flow the Red Sea is considerably higher, in exceptional cases as much as 90 or 100 inches. In the time of Darius the current setting north- wards in consequence of this difference of level would have even been stronger than at present, for the channel was narrower. But the old canal derived from the Nile gradually silted up, and the ditch cut across the isthmus became choked with sand and mud. Nevertheless the memory of the work accomplished did not perish, and more than one Egyptian ruler continued to regard the project of uniting the two seas as an enterprise glorious beyond all others. Ptolemy II. is said to have restored the canal, and, arguing from certain somewhat obscure passages in Strabo and Diodorus, some writers have even asserted that the cutting was effected directly from gulf to gulf. Skilfully constructed sluices gave access to vessels without flooding the surrounding low-lying tracts. However, the traffic between the two marine basins was doubtless insufficient to pay for the maintenance of the banks and sluices, and it has been supposed that in the reign of Cleopatra the navigable highway must already have been again closed. At least, according to Plutarch, the Egyptian queen endeavoured to have her ships transported overland to the Red Sea, in order to escape, with aU her treasures, from Octavius after the battle of Actium. Nevertheless it is quite possible that the canal may even then still have existed, if not permanently at least during the Nilotic inundations. The time when she wanted to escape happened to coincide with the period of low- water, when the canal would have been dry. After the Ptolemies the Roman conquerors took up the dream of uniting the two seas. Trajan, who tried his hand at so many great enterprises, set to work also on this project, and under the reign of Hadrian boats were navigating the
