excavating it everywhere of such depth as to come to water, and making the extent such that the circuit of it measured four hundred and twenty furlongs: and the earth which was dug out of this excavation she used up by piling it in mounds along the banks of the river: and when this had been dug by her she brought stones and set them all round it as a facing wall. Both these two things she did, that is she made the river to have a winding course, and she made the place which was dug out all into a swamp, in order that the river might run more slowly, having its force broken by going round many bends, and that the voyages might be winding to Babylon, and after the voyages there might succeed a long circuit of the pool. These works she carried out in that part where the entrance to the country was, and the shortest way to it from Media, so that the Medes might not have dealings with her kingdom and learn of her affairs.

186.