Posted: Jan 30, 1996

Herodotus on why the Nile floods in summer: (Hdt. 2.19-2.27)

From Hdt., book 2

Chapter 19

[1] When the Nile is in flood, it overflows not only the Delta but also the lands called Libyan and Arabian, as far as two days' journey from either bank in places, and sometimes more than this, sometimes less. Concerning its nature, I could not learn anything either from the priests or from any others.

[2] Yet I was anxious to learn from them why the Nile comes down with a rising flood for a hundred days from the summer solstice; and when this number of days is passed, sinks again with a diminishing stream, so that the river is low for the whole winter until the summer solstice again.

[3] I was not able to get any information from any of the Egyptians regarding this, when I asked them what power the Nile has to be contrary in nature to all other rivers. I wished to know this, and asked; also, why no breezes blew from it as from every other river* .

Chapter 20

[1] But some of the Greeks, wishing to be notable for cleverness, put forward three opinions about this river, two of which I would not even mention except just to show what they are.

[2] One of them maintains that the Etesian winds* 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.

[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.

Chapter 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.

Chapter 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] 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.

[3] In the second place, the country is rainless and frostless; but after snow has fallen, it has to rain within five days* ; so that if it snowed, it would rain in these lands. And thirdly, the men of the country are black because of the heat.

[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.

Chapter 24

[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.

Chapter 25

[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] 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.

Chapter 26

[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] 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.

[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.

[4] Meanwhile, the other rivers are swollen to high flood by the quantity of water that falls into them from the sky, because the country is rained on and cut into gullies; but in the summer they are low, lacking the rain and being drawn up too by the sun.

[5] But the Nile, being fed by no rain, and being the only river drawn up by the sun in winter, at this time falls far short of the height that it had in summer; which is but natural; for in summer all other waters too and not it alone are attracted to the sun, but in the winter it alone is afflicted.

Chapter 26

[1] I am convinced, therefore, that the sun is the cause of this phenomenon. The dryness of the air in these parts is also caused by the sun, in my opinion, because it burns its way through it; hence, it is always summer in the inland part of Libya.

[2] But were the stations of the seasons changed, so that the south wind and the summer had their station where the north wind and winter are now set, and the north wind was where the south wind is now Q if this were so, the sun, when driven from mid-heaven by the winter and the north wind, would pass over the inland parts of Europe as it now passes over Libya, and I think that in its passage over all Europe it would have the same effect on the Ister as it now does on the Nile.

Chapter 27

[1] And as to why no breeze blows from the river, this is my opinion: it is not natural that any breeze blow from very hot places; breezes always come from that which is very cold.
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