2.20.2
One of them maintains that the Etesian winds note are the cause of the river being in flood, because they hinder the Nile from emptying into the sea. But there are many times when the Etesian winds do not blow, yet the Nile does the same as before.
2.20.3
And further, if the Etesian winds were the cause, then the other rivers which flow contrary to those winds should be affected like the Nile, and even more so, since being smaller they have a weaker current. Yet there are many rivers in Syria and many in Libya, and they behave nothing like the Nile.
ch. 21
2.21.1
The second opinion is less grounded on knowledge than the previous, though it is more marvellous to the ear: according to it, the river effects what it does because it flows from Ocean, which flows around the whole world.
ch. 22
2.22.1
The third opinion is by far the most plausible, yet the most erroneous of all. It has no more truth in it than the others. According to this, the Nile flows from where snows melt; but it flows from Libya through the midst of Ethiopia, and comes out into Egypt.
2.22.2
How can it flow from snow, then, seeing that it comes from the hottest places to lands that are for the most part cooler? In fact, for a man who can reason about such things, the principal and strongest evidence that the river is unlikely to flow from snows is that the winds blowing from Libya and Ethiopia are hot.
2.22.3
In the second place, the country is rainless and frostless; but after snow has fallen, it has to rain within five days note ; so that if it snowed, it would rain in these lands. And thirdly, the men of the country are black because of the heat.
2.22.4
Moreover, kites and swallows live there all year round, and cranes come every year to these places to winter there, flying from the wintry weather of Scythia. Now, were there but the least fall of snow in this country through which the Nile flows and where it rises, none of these things would happen, as necessity proves.
ch. 23
2.23.1
The opinion about Ocean is grounded in obscurity and needs no disproof; for I know of no Ocean river; and I suppose that Homer or some older poet invented this name and brought it into his poetry.
ch. 24
2.24.1
If, after having condemned the opinions proposed, I must indicate what I myself think about these obscure matters, I shall say why I think the Nile floods in the summer. During the winter, the sun is driven by storms from his customary course and passes over the inland parts of Libya.
2.24.2
For the briefest demonstration, everything has been said; for whatever country this god is nearest, or over, it is likely that that land is very thirsty for water and that the local rivers are dried up.
ch. 25
2.25.1
A lengthier demonstration goes as follows. In its passage over the inland parts of Libya, the sun does this: as the air is always clear in that region, the land warm, and the winds cool, the sun does in its passage exactly as it would do in the summer passing through the middle of the heaven:
2.25.2
it draws the water to itself, and having done so, expels it away to the inland regions, and the winds catch it and scatter and dissolve it; and, as is to be expected, those that blow from that country, the south and the southwest, are the most rainy of all winds.
2.25.3
Yet I think that the sun never lets go of all of the water that it draws up from the Nile yearly, but keeps some back near itself. Then, as the winter becomes milder, the sun returns to the middle of the heaven, and after that draws from all rivers alike.
