266 Primitive Greece: Mycenian Art. seen at Tiryns, the outer face of the fortification wall being everywhere vertical. Around the lowest citadel the altitude of the rampart, in places, is still seven metres fifty centimetres, and seven metres to eight metres deep. On the other hand, the circuit around the upper esplanade, which carried the main buildings, offers interesting and singular constructive details. Its line is broken by salient and re-entering angles without number, which played the part of strengthening towers, and enabled the garrison to keep a sharp outlook and beat back the enemy in every direction ; whilst its thickness reaches the stupendous figure of seventeen metres fifty centimetres. In the body of the rampart were passages and recesses intended to facilitate covered communication, protect the defenders against the missiles of the assailants, and protract the defence as long as possible. There was no spring on the plateau, and no aqueduct passed at the foot of the wall, as at Mycenae ; cisterns, however, had been multiplied to save the besieged from agonizing thirst ; for this is the function which has been ascribed to several chambers destitute of doors and windows, but with an opening at the top ; their walls are overlaid with a thick coat of clay. There was no difficulty in finding the required space for these reservoirs in the depth of walls such as these. The builder's greatest constructive effort is seen in the southern wall. On the south-western side, in a kind of bastion supported by a projection of the rock, are two rectangular chambers ; they have no entrance on any side, and may have served as silos, or more probably as cisterns. The broken bricks which fill these chambers indicate that the upper portion was built of crude brick. The southern face, to the rear of the mass enclosing these reservoirs, in length measures twenty metres. Before this portion of the enclosure had been com- pletely laid bare, it was supposed to consist of two storeys : a substructure eleven metres thick, and an upper retreating section which left a free space or path six metres fifty centi- metres broad ; and in this way it was restored by Dorpfeld (Fig. 73). In the upper storey, four metres fifty centimetres, is the well-known passage with the doors leading from it. These served as sally-ports by which the defenders issued from the corridor on to the esplanade, in order to defend the castle, re- turning under shelter as soon as the attack had been repulsed.
