Amidst preparations for this expedition—and while the immense funeral pile destined for Hephæstion was being built—Alexander sailed down the Euphrates to the great dyke called Pallakopas, about ninety miles below Babylon; a sluice constructed by the ancient Assyrian kings, for the purpose of being opened when the river was too full, so as to let off the water into the interminable marshes stretching out near the western bank. The sluice being reported not to work well, he projected the construction of a new one somewhat farther down. He then sailed through the Pallakopas in order to survey the marshes, together with the tombs of the ancient Assyrian kings which had been erected among them. Himself steering his vessel, with the kausia on his head, and the regal diadem above it,[604] he passed some time among these lakes and swamps, which were so extensive that his fleet lost the way among them. He stayed long enough also to direct, and even commence, the foundation of a new city, in what seemed to him a convenient spot.[605] [604] Arrian, vii. 22, 2, 3; Strabo, xvi. p. 741. [605] Arrian, vii. 21, 11. πόλιν ἐξῳκοδόμησέ τε καὶ ἐτείχισε. On returning to Babylon, Alexander found large reinforcements arrived there—partly under Philoxenus, Menander, and Menidas, from Lydia and Karia—partly 20,000 Persians, under Peukestes the satrap. He caused these Persians to be incorporated in the files of the Macedonian phalanx. According to the standing custom, each of these files was sixteen deep, and each soldier was armed with the long pike or sarissa wielded by two hands; the lochage, or front-rank man, being always an officer receiving double pay, of great strength and attested valor—and those second and third in the file, as well as the rearmost man of all, being likewise strong and good men, receiving larger pay than the rest. Alexander, in his new arrangement, retained the three first ranks and the rear rank unchanged, as well as the same depth of file; but he substituted twelve Persians in place of the twelve Macedonians who followed after the third-rank man; so that the file was composed first of the lochage and two other chosen Macedonians, each armed with the sarissa—then of twelve Persians armed in their own manner with bow or javelin—lastly, of a Macedonian with his sarissa bringing up the the rear.[606] In this Macedonico-Persian file, the front would have only three projecting pikes, instead of five, as the ordinary Macedonian phalanx presented; but then, in compensation, the Persian soldiers would be able to hurl their javelins at an advancing enemy, over the heads of their three front-rank men. The supervening death of Alexander prevented the actual execution of this reform, interesting as being his last project for amalgamating Persians and Macedonians into one military force.