Discovering this the Peloponnesians twisted up clay in wattles of reed and threw it into the breach formed in the mound, in order to give it consistency and prevent its being carried away like the soil. Stopped in this way the Plataeans changed their mode of operation, and digging a mine from the town calculated their way under the mound, and began to carry off its material as before. This went on for a long while without the enemy outside finding it out, so that for all they threw on the top their mound made no progress in proportion, being carried away from beneath and constantly settling down in the vacuum. But the Plataeans, fearing that even thus they might not be able to hold out against the superior numbers of the enemy, had yet another invention. They stopped working at the large building in front of the mound, and starting at either end of it inside from the old low wall, built a new one in the form of a crescent running in towards the town; in order that in the event of the great wall being taken this might remain, and the enemy have to throw up a fresh mound against it, and as they advanced within might not only have their trouble over again, but also be exposed to missiles on their flanks. While raising the mound the Peloponnesians also brought up engines against the city, one of which was brought up upon the mound against the great building and shook down a good piece of it, to the no small alarm of the Plataeans. Others were advanced against different parts of the wall but were lassoed and broken by the Plataeans; who also hung up great beams by long iron chains from either extremity of two poles laid on the wall and projecting over it, and drew them up at an angle whenever any point was threatened by the engine, and loosing their hold let the beam go with its chains slack, so that it fell with a run and snapped off the nose of the battering ram.