When the Euphrates ceases, by running in its channel, to afford protection[539] to those who dwell on its banks, which it does when it approaches the confines of Charax, the country is immediately infested by the Attali, a predatory people of Arabia, beyond whom are found the Scenitæ.[540] The banks along this river are occupied by the Nomades of Arabia, as far as the deserts of Syria, from which, as we have already stated,[541] it takes a turn to the south,[542] and leaves the solitary deserts of Palmyra. Seleucia is distant, by way of the Euphrates, from the beginning of Mesopotamia, eleven hundred and twenty-five; from the Red Sea, by way of the Tigris, two hundred and twenty; and from Zeugma, seven hundred and twenty-three, miles. Zeugma is distant from Seleucia[543] in Syria, on the shores of our sea, one hundred and seventy-five[544] miles. Such is the extent of the land that lies in these parts between the two seas.[545] The length of the kingdom of Parthia is nine hundred and eighteen miles.
There is, besides the above, another town in Mesopotamia, on the banks of the Tigris and near its confluence with the Euphrates, the name of which is Digba.[546] (27.) But it will be as well now to give some particulars respecting the Tigris itself. This river rises in the region of Greater Armenia,[547] from a very remarkable source, situate on a plain. The name of the spot is Elegosine,[548] and the stream, as soon as it begins to flow, though with a slow current, has the name of Diglito.[549] When its course becomes more rapid, it assumes the name of Tigris,[550] given to it on account of its swiftness, that word signifying an arrow in the Median language. It then flows into Lake Arethusa,[551] the waters of which are able to support all weighty substances thrown into them, and exhale nitrous vapours. This lake produces only one kind of fish, which, however, never enter the current of the river in its passage through the lake: and in a similar manner, the fish of the Tigris will never swim out of its stream into the waters of the lake. Distinguishable from the lake, both by the rapidity and the colour of its waters, the tide of the river is hurried along; after it has passed through and arrived at Mount Taurus, it disappears[552] in a cavern of that mountain, and passing beneath it, bursts forth on the other side; the spot bears the name of Zoroande.[553] That the waters on either side of the mountain are the same, is evident from the fact, that bodies thrown in on the one side will reappear on the other. It then passes through another lake, called Thospites, and once more burying itself in the earth, reappears, after running a distance of twenty-two miles, in the vicinity of Nymphæum.[554] Claudius Cæsar informs us that, in the district of Arrene[555] it flows so near to the river Arsanias,[556] that when their waters swell they meet and flow together, but without, however, intermingling. For those of the Arsani, as he says, being lighter, float on the surface of the Tigris for a distance of nearly four miles, after which they separate, and the Arsanias flows into the Euphrates. The Tigris, after flowing through Armenia and receiving the well-known rivers Parthenias and Nicephorion, separates the Arabian Orei[557] from the Adiabeni, and then forms by its course, as previously mentioned, the country of Mesopotamia. After traversing the mountains of the Gordyæi,[558] it passes round Apamea,[559] a town of Mesene, one hundred and twenty-five miles on this side of Babylonian Seleucia, and then divides into two channels, one[560] of which runs southward, and flowing through Mesene, runs towards Seleucia, while the other takes a turn to the north and passes through the plains of the Cauchæ,[561] at the back of the district of Mesene. When the waters have reunited, the river assumes the name of Pasitigris. After this, it receives the Choaspes,[562] which comes from Media; and then, as we have already stated,[563] flowing between Seleucia and Ctesiphon, discharges itself into the Chaldæan Lakes, which it supplies for a distance of seventy miles. Escaping from them by a vast channel, it passes the city of Charax to the right, and empties itself into the Persian Sea, being ten miles in width at the mouth. Between the mouths of the two rivers Tigris and the Euphrates, the distance was formerly twenty-five, or, according to some writers, seven miles only, both of them being navigable to the sea. But the Orcheni and others who dwell on its banks, have long since dammed up the waters of the Euphrates for the purposes of irrigation, and it can only discharge itself into the sea by the aid of the Tigris.