THE SIEGE OF PLATA Ε A 333
calculation would be oftener right than wrong ; for they repeated the process again and again, and, the distance not being great, they could see the wall dis- tinctly enough for their purpose. In this manner they ascertained the proper length of the ladders, taking as a measure the thickness of the bricks.
The Peloponnesian wall was double, and consisted of an inner circle looking towards Plataea, and an outer intended to guard against an attack from Ath- ens ; they were at a distance of about sixteen feet from one another. This interval of sixteen feet was partitioned off into lodgings for the soldiers, by which the two walls were joined together, so that they ap- peared to form one thick wall with battlements on both sides. At every tenth battlement there were large towers, filling up the space between the walls, and extending both to the inner and outer face ; there was no way at the side of the towers, but only through the middle of them. During the night, whenever there was storm and rain, the soldiers left the battle- ments and kept guard from the towers, which were not far from each other and were covered overhead. Such was the plan of the wall with which Plataea was invested.
When the Plataeans had completed their prepara- tions they took advantage of a night on which there was a storm of wind and rain and no moon, and sal- lied forth. They were led by the authors of the at- tempt. First of all they crossed the ditch which sur- rounded the town ; then they went forward to the wall of the enemy. The guard did not discover them, for the night was so dark that they could not be seen, while the clatter of the storm drowned the noise of their approach. They marched a good way apart
