Frequent allusion has been made, in the course of this description of the Tigris and Euphrates, to the fact of their having each a flood season. Herodotus is scarcely correct when he says that in Babylonia “the river does not, as in Egypt, overflow the corn-lands of its own accord, but is spread over them by the help of engines.” Both the Tigris and Euphrates rise many feet each spring, and overflow their banks in various places. The rise is caused by the melting of the snows in the mountain regions from which the two rivers and their affluents spring. As the Tigris drains the southern, and the Euphrates the northern side of the same mountain range, the flood of the former stream is earlier and briefer than that of the latter. The Tigris commonly begins to rise early in March, and reaches its greatest height in the first or second week of May, after which it rapidly declines, and returns to its natural level by the middle of June. The Euphrates first swells about the middle of March, and is not in full flood till quite the end of May or the beginning of June; it then continues high for above a month, and does not sink much till the middle of July, after which it gradually falls till September. The country inundated by the Tigris is chiefly that on its lower course, between the 32d and 31st parallels, the territory of the Beni Lam Arabs. The territory which the Euphrates floods is far more extensive. As high up as its junction with the Khabour, that stream is described as, in the month of April, “spreading over the surrounding country like a sea.” From Hit downwards, it inundates both its banks, more especially the country above Baghdad (to which it is carried by the Saklawiyeh canal), the tract west of the Birs Nimrud and extending thence by way of Nedjif to Samava and the territory of the Affej Arabs, between the rivers above and below the 32d parallel. Its flood is, however, very irregular, owing to the nature of its banks, and the general inclination of the plain, whereof mention was made above. If care is taken, the inundation may be pretty equally distrib uted on either side of the stream; but if the river banks are neglected, it is sure to flow mainly to the west, rendering the whole country on that side the river a swamp, and leaving the territory on the left bank almost without water. This state of things may be traced historically from the age of Alexander to the present day, and has probably prevailed more or less since the time when Chaldaea received its first inhabitants.