may be proved by the sources of
rivers, the majority and the longest of which, as drawn and described in
geographies of the world, are found to rise in the north. First in
India, the Ganges and Indus spring from the Caucasus; in Syria, the
Tigris and Euphrates; in Pontus in Asia, the Dnieper, Bug, and Don; in
Colchis, the Phasis; in Gaul, the Rhone; in Celtica, the Rhine; on this
side of the Alps, the Timavo and Po; in Italy, the Tiber; in Maurusia,
which we call Mauretania, the Dyris, rising in the Atlas range and
running westerly to Lake Heptagonus, where it changes its name and is
called Agger; then from Lake Heptabolus it runs at the base of barren
mountains, flowing southerly and emptying into the marsh called[10]...
It surrounds Meroe, which is a kingdom in southern Ethiopia, and from
the marsh grounds there, winding round by the rivers Astansoba and
Astoboa and a great many others, it passes through the mountains to the
Cataract, and from there it dashes down, and passes to the north between
Elephantis and Syene and the plains of Thebes into Egypt, where it is
called the Nile.

[Note 10: Here something is lost, as also in chapter III, sections 5
and 6.]

7. That the source of the Nile is in Mauretania is known principally
from the fact that there are other springs on the other side of the
Atlas range flowing into the ocean to the west, and that ichneumons,
crocodiles, and other animals and fishes of like nature are found
there, although there are no hippopotamuses.

8. Therefore, since in descriptions of the world it appears that all
rivers of any size flow from the north, and since in the plains of
Africa, which are exposed to the course of the sun in the south, the
moisture is deeply hidden, springs not common, and rivers rare, it
follows that the sources of springs which lie to the north or northeast
are much better, unless they hit upon a place which is full of sulphur,
alum, or asphalt. In this case they are completely changed, and flow in
springs which have a bad smell and taste, whether the water is hot or
cold.

9. The fact is, heat is not at all a property of water, but when a
stream of cold water happens upon a hot place, it boils up, and issues
through the fissures and out of the ground in a state of heat. This
cannot last very long, but in a short time the water becomes cold. If it
were naturally hot, it would not cool off and lose its heat. Its taste,
however, and its smell and colour are not r