1. _Oceanus_ is so named by both Greeks and Latins because it flows like a circle around the circle of the land; it may be from its speed because it runs swiftly (_ocius_); or because like the heavens it glows with a dark purple color. _Oceanus_ is, as it were, κυάνεος (dark purple). It is this that embraces the shores of the lands, approaching and receding with alternate tides. For when the winds breathe in the depths, it either pushes the waters away or sucks them back. 2. And it has taken different names from the neighboring lands; as _Gallicus_, _Germanicus_, _Scythicus_, _Caspius_, _Hyrcanus_, _Atlanticus_, _Gaditanus_. The Gaditanian strait was named from _Gades_ where the entrance to the _Mare Magnum_ first opens from the Ocean. Whence when Hercules had come to Gades he placed the columns there, believing that there was the limit of the circle of the lands. Chapter 16. On the Mediterranean Sea. 1. The _Mare Magnum_ is that which flows from the west out of the Ocean and extends toward the South, and then stretches to the North. And it is called _Magnum_ because the rest of the seas are smaller in comparison with it. It is also called Mediterranean because it flows through the midst of the land (_per mediam terram_) as far as the Orient, separating Europe and Africa and Asia. Chapter 20. On the abyss. 1. The abyss is the deep water which cannot be penetrated; whether caverns of unknown waters from which springs and rivers flow; or the waters that pass secretly beneath, whence it is called abyss. For all waters or torrents return by secret channels to the abyss which is their source. Chapter 21. On rivers. 6. Certain of the rivers have received their names from causes peculiar to them, and of these some which are told of as famous in history should be mentioned. 7. Geon is a river issuing from Paradise and surrounding the whole of Ethiopia, being called by this name because it waters the land of Egypt by its flood, for γῆ in the Greek means _terra_ in the Latin. This river is called Nile by the Egyptians, on account of the mud which it brings, which gives fertility. 8. The river Ganges, which the holy Scriptures call Phison, issuing from Paradise, takes its course toward the regions of India.... It is said to rise in the manner of the Nile and overflow the lands of the East. 9. The Tigris, a river of Mesopotamia, rises in Paradise, and flows opposite the Assyrians (_contra Assyrios_), and after many windings flows into the Dead Sea. And it is called by this name because of its velocity, like a wild beast that runs with great speed.