64 A History of Art in Ciiald.ka and Assyria. 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." 1 As for Ctesias, he speaks of a width "greater than what is necessary to allow two chariots to pass each other." 2 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. 3 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. Throughout the circumference of the enceinte the. curtain was strengthened by rectangular flanking towers having a front of forty- five, and a salience of rather more than thirteen feet. 4 These were separated from each other by intervals of ninety feet, or double the front of a tower. Only the lower parts of the towers are now in existence, and we have to turn to the representations 1 Herodotus, i. 179. Herodotus says that the Chaldosans constructed buildings of a single chamber along each parapet of the wall, leaving room between them for a four-horse chariot to turn. His words are : €7rai/to Se rov ret^eos irapa ra eo-^ara, OLKrjfj.aTa /lovvoKtuXa eSujMiv, reTpa/x/xéVa is akX.7]a' to (xlcrov Se rtoi/ ot/<7//xara)i/ eXiTrov TeOf) i.TTTTdi 7TÇ.f)Û(J.mV. ED. 2 DlODORUS, ii. vii. 4. 3 In many carved pictures of sieges we see soldiers who appear to be digging mines (Layard, Monuments, series i. plates 19, 20, 66. Rawlinson, The Five Great Monarchies, vol. i. p. 473). 4 Placf, Ni?iire, vol. i. p. 165; vol. ii. p. 11.