We need not discuss in this place the phenomenon last mentioned, except to remark that the story may well have been suggested by the propinquity of the sources of the Diarbekr branch of the Tigris to the stream of the Murad, the ancient Arsanias. The country of Arrhene is probably the same as that better known as Arzanene, which is comprised within the present vilayet of Diarbekr. Our present interest in the passage lies in the statements relative to the Tigris, that it flows through two lakes called Arethusa and Thospites. Strabo, in speaking of the same phenomenon, attributes it to one lake only, namely that of Arsene or Thopitis. The river, according to him, rises in the Niphates mountains, by which name he seems to be referring to the Nepat of Armenian writers, the modern Ala Dagh. After flowing through Lake Thopitis it disappears in a chasm at the corner of the lake. It comes to light again in the province of Chalonitis; and, although later on he attributes that province to the Zagros, I cannot help thinking that the sense which his informants wished to convey was that it came to light in the mountains of the peripheral region. The mention of two lakes by Pliny need not perplex us over-much; for his Arethusa no doubt denotes the Arjish arm of Lake Van, and his Thospites the principal body of water with the city of Van, the Dhuspas of the cuneiform inscriptions, upon its eastern shore. Ptolemy, on the other hand, entangles the subject still further by separating the lakes of Areesa--no doubt the Arethusa of Pliny--and Thospitis by four degrees of longitude. This geographer does not give us any indications as to the properties of the lake waters; but he tells us that the Tigris is partly a river of Armenia and that its sources constitute Lake Thospitis. The position which he assigns to the town of Artemita--which is probably the modern Artemid--is further evidence that in speaking of Lake Areesa or Arsissa he was in fact referring to Lake Van. One cannot help concluding that his Thospitis with the town of Thospia was actually the self-same sheet of water. The discrepancy in longitude finds a parallel in the degrees assigned by this writer to Lakes Sevan and Urmi. They are really upon the same degree. Yet Ptolemy, under the names of Lychnitis and Martianes, assigns to them the difference of over four degrees.