remes and pentecon-ters, as best
capable of withstanding the force of an angry sea. Bridges of this
kind were intended sometimes for temporary, sometimes for permanent
constructions. In the latter case, great care and much engineering skill
was lavished on their erection. The shore cables, which united the ships
together, and sustained the actual bridge or platform, were made of most
carefully selected materials, and must have been of enormous strength;
the ships were placed in close proximity one to another; and by the
substitution of a double for a single line--of two bridges, in fact, for
one--the solidity of the work was very largely augmented. Yet, rare as
was the skill shown, solid and compact as were the causeways thus
thrown by human art over the sea, they were found inadequate to the end
desired. The great work of Xerxes, far the most elaborate of its class,
failed to withstand the fury of the elements for a single year; the
bridge, constructed in one autumn, was utterly swept away in the next;
and the army which had crossed into Europe by its aid had to embark as
it best could, and return on board ship to Asia.

As the furnishing of the Persian fleet was left wholly to the subject
nations of the Empire, so was its manning intrusted to them almost
entirely. Phoenicians, Syrians, Egyptians, Cypriots, Cilicians, Lycians,
Pamphylians, Carians, Greeks, equipped in the several costumes of their
countries, served side by side in their respective contingents of ships,
thereby giving the fleet nearly the same motley appearance which
was presented by the army. In one respect alone did the navy exhibit
superior uniformity to their sister service--the _epibatae_, or
"marines," who formed the whole fighting force of the fleet while it
kept the sea, was a nearly homogeneous body, consisting of three races
only (two of which were closely allied), namely, Persians, Medes, and
Sacse. Every ship had thirty such men on board; all, it is probable,
uniformly armed, and all animated by one and the same spirit. To this
force the Persians must have owed it mainly that their great fleets
were not mere congeries of mutually repellant atoms, but were capable of
acting against an enemy with a fair amount of combination and singleness
of purpose.

When a fleet accompanied a land army upon an expedition, it was usually
placed under the same commander. This commander, however, was not
expected to adventure himself on board much less to tak