ources. But
there is no necessity for travelling beyond the line of ordinary human
motive in order to discover a reason for the works in question. The
bridge across the Hellespont was a mere repetition of the construction
by which Darius had passed into Europe when he made his Scythian
expedition, and probably seemed to a Persian not a specially dignified
or very wonderful way of crossing so narrow a strait, but merely the
natural mode of passage. The only respect in which the bridge of Xerxes
differed from constructions with which the Persians were thoroughly
familiar, was in its superior solidity and strength. The shore-cables
were of unusual size and weight, and apparently of unusual materials;
the formation of a double line--of two bridges, in fact, instead of
one--was almost without a parallel; and the completion of the work by
laying on the ordinary plank-bridge a solid causeway composed of earth
and brushwood, with a high bulwark on either side, was probably, if not
unprecedented, at any rate very uncommon. Boat-bridges were usually,
as they are even now in the East, somewhat rickety constructions, which
animals unaccustomed to them could with difficulty be induced to cross.
The bridge of Xerxes was a high-road, as AEschylus calls it along, which
men, horses, and vehicles might pass with as much comfort and facility
as they could move on shore.

The utility of such a work is evident. Without it Xerxes must have been
reduced to the necessity of embarking in ships, conveying across the
strait, and disembarking, not only his entire host, but all its stores,
tents, baggage, horses, camels, and sumpter-beasts. If the numbers of
his army approached even the lowest estimate that has been formed of
them, it is not too much to say that many weeks must have been spent in
this operation. As it was, the whole expedition marched across in seven
days. In the case of ship conveyance, continual accidents would have
happened: the transport would from time to time have been interrupted by
bad weather; and great catastrophes might have occurred. By means of the
bridge the passage was probably effected without any loss of either man
or beast. Moreover, the bridge once established, there was a safe
line of communication thenceforth between the army in Europe and the
headquarters of the Persian power in Asia, along which might pass
couriers, supplies, and reinforcements, if they should be needed.
Further, the grandeur, massiveness, an