158 SIEGE OF PLATA EA [11 lating the direction, they dug a mine from the city to the mound and again drew the earth inward. For a long time their assailants did not find them out, and so what the Pcloponnesians threw on was of little use, since the mound was always being drawn off below and settling into the vacant space. But in spite of all their efforts, the Plataeans were afraid that their numbers would never hold out against so great an army; and they devised yet another expedient. They left off working at the great building opposite the mound, and beginning at both ends, where the city wall returned to its original lower height, they built an inner wall projecting inwards in the shape of a crescent, that if the first wall were taken the other miglit still be defensible. The enemy would be obliged to begin again and carry the mound right up to it, and as they advanced inwards would have their trouble all over again, and be exposed to missiles on both flanks. While the mound was rising the Pcloponnesians brought battering engines up to the wall ; one which was moved forward on the mound itself shook a great part of the raised building, to the terror of the Plataeans. They brought up others By iHgcnioHs devices too at Other points of the wall. But they disable the battering- the Plataeans dropped nooses over the rams 0/ the enemy. ^^^^ ^f jj^^^g^ engines and drew them up ; they also let down huge beams suspended at each end by long iron chains from two poles leaning on the wall and projecting over it. These beams they drew up at right angles to the advancing battering-ram, and whenever at any point it was about to attack them they slackened their hold of the chains and let go the beam, which fell with great force and snapped off the head of the ram. 77 At length the Pcloponnesians, finding that their engines The Peloponnesians ^ere useless, and that the new wall nearly succeed in setting was rising opposite to the mound, and the city on fire. perceiving that they could not without more formidable means of attack hope to take the city, made preparations for a blockade. But first of all they
