In which we consider the Nile

This brings us around to the topic of the mysterious Nile. Herodotus has several agenda items here.  First, why does the Nile flood every year at midsummer?  Regular as clockwork, supposedly, the Nile rises for one hundred days between 22 June and 30 September.  Then from October through May it lowers.  Most rivers flood in the springtime, not in July, so what’s up with that?  It’s a great puzzle.

Some of Herodotus’s friends have pitched ideas, hoping that he’ll include them in his book maybe, but they’re stupid ideas.  Like, one guy was all, maybe it’s the seasonal winds!  They blow towards the south, upstream, and maybe they blow so hard the water can’t flow into the wind and it builds up and floods the riverbanks instead?

But that’s dumb.  Aside from being self-evidently stupid, sometimes the wind is not blowing.  In fact it’s a rare year that the wind blows steadily for one hundred days starting on the summer solstice.  And again: it’s dumb.

Second stupid solution: something something the River Oceanus.  This doesn’t even make sense.  There isn’t even a verb; it’s just “something something River Oceanus.”  Half-quoting Homer doesn’t accomplish anything; it’s just bull hockey!  You have to do better than that to get your name included in the Histories: EURTERPE.

The third solution is the stupidest, in Herodotus’s mind.  His third drunk friend suggested that snowmelt was the major contributing factor.  Herodotus is quick to point out that the Nile flows from south of Egypt, which is equatorial and hot and the people who live there are black.  Ergo, snow melting in June is super implausible, and snow melting from June to September even more so.

No way there’s a big mountain chain down there (the Ethiopian Highlands, Mount Kilimanjaro, heck, the Rwenzori Mountains in Uganda) where some peaks are snowcapped year-round, and which catch torrential rain every summer that slowly makes its way north to the Nile.  That’d be dopey!

No, Herodotus’s theory is axial tilt.  In the summertime, see, it gets extra hot.  Way down south, it’s soooo hot, because of axial tilt, that the very sea boils, and all that water evaporates and drifts north to where it’s a little bit cooler.  Then it recondenses as floodwater!  That’s also why it’s so dry in the interior of Africa, clearly.

This theory also shoots down the idea of blaming the wind.  ‘Cause it’s hot in the south, yo!  Wind makes things cool — that’s why they call it wind chill — so obviously the wind is not a major climatological feature in central Africa.

Axial tilt.  That’s it. Having solved the problem of the annual flooding, Herodotus now turns his attention to the other great mystery of the Nile: its source!  Will Herodotus find the source of the Nile?  Will he simply repeat stories some guys told him over drinks?  Stay tuned to learn!