SCIENTIFIC journals by and large are rather dry - so much so, indeed, that when occasionally one comes across an interesting item, nicely put it brightens up one's day enormously. A recent article about the River Nile provides a case in point.
The Nile has always had an air of mystery about it. To the ancients, part of this was the way its level rose and fell with rhythmic regularity, flooding large areas and feeding the land with the rich nutrients that made its valley fertile.
We now know that this seasonal flooding has its origins in tropical rains and melting snows, whose waters surge northwards each year, reaching Aswan by the end of June and finally arriving at Memphis and the delta region by September. Then the waters gradually subside, until the river reaches its lowest level about now, in April.
But one of the greatest enigmas of the Nile, one which captured the imagination of generations from ancient times until the puzzle was solved by Sir Samuel Baker 140 years ago, was where it came from the location of its source.
The answer is summarised beautifully by a modestly almost anonymous N. Sehmi, in a recent issue of the Bulletin of the World Meteorological Organisation.
"Fed by the eternal snows of the Ruwenzori mountains, the legendary Nile springs south of the Equator in Burundi, Central Africa, and flows through Lake Victoria before emptying into Lake Kyoga and thundering down the Murchison Falls to Lake Mobuto. It then saunters through milliards of runnels of the Sudd, one of the world's biggest swamps, losing about 70 per cent of its water in the process by evapotranspiration.
"The Nile then enters the stony desert, before plunging down a dozen basaltic cataracts to Khartoum, the capital of Sudan.
"At Khartoum, the lethargic White Nile is rejuvenated, mainly during the rainy season, by the turbulent Blue Nile which descends from the lofty Ethiopian highlands and constitutes 86 per cent of the flow into Lake Nasser. Finally, the Nile pours into the Mediterranean Sea through a huge delta after a journey which covers half the African continent and thousands of years of human civilisation."
When I come across a passage of this kind, I am always reminded of Oscar Wilde's famous compliment to James McNeill Whistler on a pithy aphorism, neatly turned: "I wish I'd said that," said Wilde. Even more relevant is Whistler's quick reply: "Don't worry, you will, Oscar, you will."