his fleet, and
sailed down the same stream which Nearchus had sailed up. At the head of
the Delta, the vessels which had suffered most in Nearchus' voyages were
directed to proceed with the troops they had on board, through a canal
which runs into the Tigris, Alexander himself proceeding with the lightest
and best sailing vessels through the Delta to the sea.

Soon after his return to Opis, where the mutiny of his troops took place,
Alexander gave another proof of his attention to maritime affairs; for he
despatched Heraclides into Hyrcania, with orders to cut timber and prepare
a fleet for the purpose of exploring the Caspian Sea--an attempt which,
like that of the projected voyage of Nearchus up the Arabian Gulf, was
prevented by Alexander's death. In the mean time Nearchus had been
collecting the vessels that were destined for his expedition; they were
assembled at Babylon: to this city also were brought from Phoenicia
forty-seven vessels which had been taken to pieces, and so conveyed over
land to Thapsacus. Two of these were of five banks, three of four, twelve
of three, and thirty rowed with fifteen oars on a side. Others likewise
were ordered to be built on the spot of cypress, the only wood which
Babyloni afforded; while mariners were collected from Phoenicia, and a dock
was directed to be cut capable of containing one thousand vessels, with
buildings and arsenals in proportion to the establishment. To accomplish
this extensive design, Alexander had sent one of his officers to Phoenicia
with 500 talents (about 106,830_l_.) to buy slaves fit for the oar, and
hire mariners. These preparations were so extensive, that it seems highly
probable that Alexander meant to conquer Arabia, as well as explore the
navigation of the Arabian Gulf; and indeed his plan and policy always were
to unite conquest with discovery. As soon as he had put these preparations
in a proper train, he again embarked, and sailed down the Euphrates as far
as Pallacopas. The immediate object of this voyage is not exactly known. As
the Euphrates flows over the adjacent country at certain seasons, the
Persian monarchs had cut a canal at Pallacopas, which diverted its
superfluous waters into a lake, where they were employed to flood the land.
This and similar canals had been long neglected; but as Alexander seems to
have fixed on Babylon as the future capital of his empire, it was necessary
to restore the canals to their original utility, in order that