ARAS, the ancient Araxes (Turk, and Arab. Has, Armen. Erash, Georg. Rashki), a river which rises south of Erze-roum, in the Bingöl-Dagh (Mountain of the Thousand Wells), and flows east through the province of Erzeroum and Russian Armenia, passing between Mount Ararat and Erivan, till it joins the Kur {Cyrus') coming from the north, and falls with it into the Caspian Sea. Its separate course is about 500 miles long, and it receives a number of tributaries, of which one of the chief is the Zenghi, which passes by Erivan and drains lake Goukcha or Sivan. A number of towns are situated on the banks of the Aras, as Hassan-Kaleh, Kagisman, and Abbasabad. It forms the boundary between Russia and Persia from 44° to 48° E. long. The Araxes was known by hearsay to Herodotus, and is the Phasis of Xenophon. It is a rapid and muddy stream, dangerous to cross when swollen by the melting of the snows in Armenia, but fordable in its ordinary state.