It must not be supposed that the entire plateau of which we have been speaking is to the eye a single level and unbroken plain. In the western portion of the region the plains are constantly intersected by “brown, irregular, rocky ridges,” rising to no great height, but serving to condense the vapors held in the air, and furnishing thereby springs and wells of inestimable value to the inhabitants. In the southern and eastern districts “immense” ranges of mountains are said to occur; and the south-eastern as well as the north-eastern corners of the plateau are little else than confused masses of giant elevations. Vast flats, however, are found. In the Great Salt Desert, which extends from Kashan and Koum to the Deriah or “Sea” in which the Helmend terminates, and in the sandy desert of Seistan, which lies east and south-east of that lake, reaching from near Furrah to the Mekran mountains, plains of above a hundred miles in extent appear to occur, sometimes formed of loose sand, which the wind raises into waves like those of the sea, sometimes hard and gravelly, or of baked and indurated clay. The tract in question, which at the present day is divided between Afghanistan, Beloochistan, and Iran, contained, at the time when the Persian Empire arose, the following nations: the Sagartians, the Cossseans, the Parthians, the Hariva or Arians, the Gandarians, the Sattagydians, the Arachotians, the Thamanseans, the Sarangae, and the Paricanians. The Sagartians and Cossseans dwelt in the western portion of the tract, the latter probably about the Siah-Koh mountains, the former scattered over the whole region from the borders of Persia Proper to the Caspian Gates and the Elburz range. Along its northern edge, east of the Sagartians, were the Parthians, the Arians, and the Gandarians. occurring in that order as we proceed from west to east. The Parthians held the country known now as the Atak or “Skirt,” the flat tract at the southern base of the Elburz from about Shahrud to Khaff, together with a portion of the mountain region adjoining. This is a rich and valuable territory, well watered by a number of small streams, which, issuing from the ravines and valleys of the Elburz, spread fertility around, but lose themselves after a short, course in the Salt Desert. Adjoining the Parthians upon the east were the Haroyu, Hariva, or Arians, an Iranic race of great antiquity, who held the country along the southern skirts of the mountains from the neighborhood of Khaff to the point where the Heri-rud (Arius) issues from the Paropamisan mountains. The character of this country closely resembles that of Parthia, whereof it is a continuation; but the copious stream of the Heri-rud renders it even more productive.