Pliny the Elder, Natural History 6.100

6.100

ostium Euphratis, lacus quem faciunt Eulaeus et Tigris iuxta Characen, inde Tigri Susa. festos dies ibi agentem Alexandrum invenerunt septimo mense post quam digressus ab iis fuerat Patalis, tertio navigationis. sic Alexandri classis navigavit; postea ab Syagro Arabiae promunturio Patalen favonio, quem hippalum ibi vocant, peti certissimum videbatur, |XIII|.XXXII p. aestimatione.

and then the river Granis, navigable for vessels of small burden, and flowing through Susiane; the Deximontani, a people who manufacture bitumen, dwell on its right bank. The river Zarotis comes next, difficult of entrance at its mouth, except by those who are well acquainted with it; and then two small islands; after which the fleet sailed through shallows which looked very much like a marsh, but were rendered navigable by certain channels which had been cut there. They then arrived at the mouth of the Euphrates, and from thence passed into a lake which is formed by the rivers Eulæus and Tigris, in the vicinity of Charax, after which they arrived at Susa, on the river Tigris. Here, after a voyage of three months, they found Alexander celebra- ting a festival, seven months after he had left them at Patale. Such was the voyage performed by the fleet of Alexander. In later times it has been considered a well-ascertained fact that the voyage from Syagrus, the Promontory of Arabia, to Patale, reckoned at thirteen hundred and thirty-five miles, can be performed most advantageously with the aid of a westerly wind, which is there known by the name of Hippalus.