The lower Euphrates--Irâc Araby[101]--is in striking contrast with the region just described. The two great rivers of Mesopotamia, while yet more than 500 miles above the sea, draw close to one another. Below this point, the land, naturally rich, is easily supplied with water, and when irrigated is exuberantly fertile. Instead of joining where they approach, the two rivers still keep apart, and for two or three hundred miles, running parallel, inclose what was the memorable plain of Dura. The country (as now) was covered with long hillocks and mounds, the remains of an ancient network of irrigation,[102] and also strewed with fragments of brick and pottery, remnants of the dim ages of antiquity. At the time of which we write, the face of the land was not, as it is for the most part now, a barren waste, but richly cultivated and irrigated by canals. On the Tigris, a little below the point of its drawing near the Euphrates, was Medâin, ‘the twin city’ (combining the sites of both Seleucia and Ctesiphon), at this time the capital of Persia. Fifty miles to the south of it a series of shapeless mounds, looking down on the ‘great river’ Euphrates, marked the site of ancient Babylon, and from their summit, still to the south, might be descried the Birs Nimrûd (or ‘Tower of Babel’) rearing its weird head on the horizon of the verdant plain. Some thirty miles yet further south lay Hîra, the capital of the Lakhmites and of the Arab tribes around. It stood (like its successor Kûfa) upon the Bâdacla, a branch which issues from the right bank of the Euphrates by a channel in the live rock, sixteen miles above Babylon, cut by the hand of man, but of unknown antiquity.[103] Sweeping to the west of the parent river, the rival stream, in its southward course, feeds many marshes, and especially the great lake called the ‘Sea of Najaf; after a wide circuit it rejoins the Euphrates above its junction with the Tigris. There was in olden times another branch still further to the west, the _Khandac_, or ‘Trench of Sapor,’ which intended as a bar to Bedouin incursions, and, taking a yet wider circuit, fell into the Euphrates near Obolla, at the head of the Persian Gulf. This is now dry, but originally it carried a stream which, like the other, helped materially to widen the green belt continually narrowed and pressed in upon by the dry and sandy desert beyond. The lower delta again has features of its own. It is subject to tidal flow for fifty miles above the junction of the two rivers. Alluvial, low, and watered with ease, it is covered with a sea of corn, and has, not without reason, been called ‘the garden of the world.’ Besides the familiar palm, the country abounded with the fig, mulberry, and pomegranate. But the climate was close and oppressive; the fens and marshes, always liable to inundation, were aggravated by the neglect of dams and sluices in those days of anarchy;[104] and the Arab, used to the sandy steppes