Plan of a canal.
Mardonius had no desire to encounter this danger again. Now the promontory of Mount Athos, though high and rocky itself, was connected with the main land by an isthmus level and low, and not very broad. Xerxes determined on cutting a canal through this isthmus, so as to take his fleet of galleys across the neck, and thus avoid the stormy navigation of the outward passage. Such a canal would be of service not merely for the passage of the great fleet, but for the constant communication which it would be necessary for Xerxes to maintain with his own dominions during the whole period of the invasion.
The Greeks do not interfere.
It might have been expected that the Greeks would have interfered to prevent the execution of such a work as this; but it seems that they did not, and yet there was a considerable Greek population in that vicinity. The promontory of Athos itself was quite extensive, being about thirty miles long and four or five wide, and it had several towns upon it. The canal which Xerxes was to cut across the neck of this peninsula was to be wide enough for two triremes to pass each other. Triremes were galleys propelled by three banks of oars, and were vessels of the largest class ordinarily employed; and as the oars by which they were impelled required almost as great a breadth of water as the vessels themselves, the canal was, consequently, to be very wide.
Plans of the engineers.
The engineers, accordingly, laid out the ground, and, marking the boundaries by stakes and lines, as guides to the workmen, the excavation was commenced. Immense numbers of men were set at work, arranged regularly in gangs, according to the various nations which furnished them. As the excavation gradually proceeded, and the trench began to grow deep, they placed ladders against the sides, and stationed a series of men upon them; then the earth dug from the bottom was hauled up from one to another, in a sort of basket or hod, until it reached the top, where it was taken by other men and conveyed away.
Prosecution of the work.
The work was very much interrupted and impeded, in many parts of the line, by the continual caving in of the banks, on account of the workmen attempting to dig perpendicularly down. In one section—the one which had been assigned to the Phœnicians—this difficulty did not occur; for the Phœnicians, more considerate than the rest, had taken the precaution to make the breadth of their part of the trench twice as great at the top as it was below. By this means the banks on each side were formed to a gradual slope, and consequently stood firm. The canal was at length completed, and the water was let in.
The Strymon bridged.
North of the promontory of Mount Athos the reader will find upon the map the River Strymon, flowing south, not far from the boundary between Macedon and Thrace, into the Ægean Sea. The army of Xerxes, in its march from the Hellespont, would, of course, have to cross this river; and Xerxes having, by cutting the canal across the isthmus of Mount Athos, removed an obstacle in the way of his fleet, resolved next to facilitate the progress of his army by bridging the Strymon.