secret mine, which they carried under the mound from within the city by conjecture, fetched away the earth again, and were a long time undiscovered; so that the earth being continually carried out below, it was no use to cast fresh stuff on the mound, which still settled down into the excavation. Nevertheless, fearing that they should not be able even thus to hold out, being few against many, they devised this further; they gave over working at the high wall against the mound, and beginning at both ends of it, where the wall was low, built another wall in form of a crescent, inward to the city, that, if the great wall were taken, this might resist, and put the enemy to make another mound, in the continuing of which further inwards they should have their labour over again, and withal should be more exposed on either side to missile weapons. And at the same time that they were raising the mound, the Peloponnesians brought to the city their engines of battery; one of which, by help of the mound, they applied to the high wall, wherewith they much shook it, and put the Platæans into great fear; and others to other parts of the wall, which the Platæans broke partly by casting ropes about them, and partly with great beams, which being hung in long iron chains by either end upon two other great beams jetting over, and inclining from above the wall like two horns, they drew up to them in a horizontal position, and when the engine was about to make a blow any where, they let go the chains and let the beam fall, which, by the violence of its descent, broke off the head of the battering–ram.