At Khorsabad this stood on a plinth three feet eight inches high, above which began the sun-dried brick. The whole is even now nowhere less than forty-five feet high, while in parts it reaches a height of sixty feet. If we remember how greatly walls built of the materials here used must have suffered from the weather, we shall no longer be astonished at the height ascribed by Herodotus to the walls of Babylon: “These were, he says, 200 royal cubits (348 feet) high.”[81] This height was measured, no doubt, from the summit of the tallest towers into the deepest part of the ditch, which he adds, “was wide and deep.” It is possible that the interpreters who did the honours of Babylon to the Greek historian exaggerated the figures a little, just as those of Memphis added something to the height of the pyramids. That the exaggeration was not very great is suggested by what he says as to the thickness of the wall; he puts it at fifty royal cubits, or eighty-six feet six inches. Now those of Khorsabad are only between six and seven feet thinner than this, and it is certain that the walls of Babylon, admired by all antiquity as the masterpieces of the Chaldæan engineers, must have surpassed those of the city improvised by Sargon both in height and thickness. Far from abusing our credulity, Herodotus is within the mark when he says that on the summit of the wall “enough room was left between the towers to turn a four-horse chariot.”[82] As for Ctesias, he speaks of a width “greater than what is necessary to allow two chariots to pass each other.”[83] Such thicknesses were so far beyond the ideas of Greek builders that their historians seem to have been afraid that if they told the truth they would not be believed, so they attenuated rather than exaggerated the real dimensions. If we give a chariot a clear space of ten feet, which is liberal indeed, it will be seen that not two, but six or seven, could proceed abreast on such walls. The nature of the materials did not allow walls to be thin, and in making them very thick there were several great advantages. The Assyrians understood the use of the battering-ram. We see it employed in several of the bas-reliefs for opening a breach in the ramparts of a beleaguered town (Vol. I. Fig. 60 and above, Fig. 23). They also dug mines, as soon as they had pierced the revetment of stone or burnt brick.[84] To prevent or to neutralize the employment of such methods of attack they found no contrivance more effectual than giving enormous solidity to their walls. Against such masses the battering-ram would be almost powerless, and mines would take so much time that they would not be very much better. Finally, the platform at the summit of a wall built on such principles would afford room for a number of defenders that would amount to a large army.