Now it will be in place to touch briefly on the most helpful of all rivers, the Nile, which Homer calls the Aegyptus,Cf. Odyss. iv. 477. On the Nile and its floods, see Hdt. ii. 19, 20; Diod. Sic. i. 36; Strabo, xvii. 1, 5; Pliny, v. 51 ff. and then to describe other remarkable things to be found in those lands.

The origin of the sources of the Nile (so at least I am wont to think) will be unknown also to future ages, as it has been up to the present. But, since the poets’ tales and dissenting geographers give varying accounts of this unknown subject, I shall succinctly set forth such of their views as in my opinion approach the truth.

Some natural philosophers affirm that in the tracts lying beneath the north, when the cold winters freeze everything, great masses of snow are congealed; that afterwards when these are melted by the heat of the blazing sun, they form clouds filled with flowing moisture, which are then driven towards the south by the Etesian winds,Periodic winds which blow yearly in the dog-days, according to Colum. xi. 2, 56, from August 1 to 30; cf. Pliny, ii. 124; xviii. 270 f. The , forerunners, mentioned below in section 7, begin eight days earlier. and when melted by the excessive warmth, are believed to cause the rich overflow of the Nile.

Others assert that it is by the Aethiopian rains, which are said to fall in abundance in those regions in the season of torrid heat, that its floods are raised at the appointed season of the year; but both these reasons seem to be out of harmony with the truth. For it is reported that in the land of the Aethiopians rains fall either not at all or at long intervals of time.

Another, more widespread opinion is, that when the Prodromoi blow and after them the Etesians for forty-five consecutive days, since they drive back the course of the river and check its speed, it swells with overflowing waves; and while the contrary wind blows against it, it increases more and more, since on the one side the force of the wind hurls it back and on the other the flow of its perennial springs forces it onward; and rising high it covers everything, and hiding the ground, over the low-lying plains it has the appearance of a sea.