NILE CANALS — DIVERSION OF EIVERS. 483- 



river burst tlirougli the obstructions which had now choked up 

 its ancient channel, and resumed its original course.* 



It was probably such facts as these that suggested to ancient 

 engineers the possibihty of like artificial operations, and there 

 are numerous instances of the execution of works for this pur- 

 pose in very remote ages. The Bahr Jusef, the great stream 

 which suppHes the Fayoum with water from the Mle, has been 

 supposed, by some wi-iters, to be a natural channel ; but both it 

 and the Bahr el Wady are almost certainly artificial canals con- 

 structed to water that basin, to regulate the level of Lake Mceris, 

 and possibly, also, to diminish the dangers resulting from excess- 

 ive inundations of the Nile, by serviug as waste-weirs to discharge 

 a part of its overflowing waters, f Several of the seven ancient 

 mouths of the Nile are believed to be artificial channels, and 

 Herodotus even asserts that King Menes diverted the entire 

 course of that river from the Libyan to the Arabian side of the 

 valley. There are traces of an ancient river-bed along the west- 

 ern mountains, which give some countenance to this statement. 

 But it is much more probable that the works of Menes were de- 

 signed rather to prevent a natural, than to produce an artificial, 

 change .in the channel of the river. 



Two of the most celebrated cascades in Europe, those of the 

 Teverone at Tivoli and of the Yelino at Terni, owe, if not their 

 existence, at l£ast their position and character, to the diversion of 

 their waters from their natural beds into new channels, in order 

 to obviate the evils produced by their frequent floods. Remark- 

 able works of the same sort have been executed in Switzerland 

 in very recent times. Until the year 1714, the Kander, which 

 drains several large Alpine valleys, ran for a considerable dis- 

 tance parallel with the Lake of Thun, and a few miles below the 

 city of that name emptied into the river Aar. It frequently 

 flooded the flats along the lower part of its course, and it was de- 

 termined to divert it into the Lake of Thun. For this piirpose, 



* Mardignt, Memoir e mr les Inondations de VArdkche, p. 13. 



f The starting-points of these canals were far up the Nile, and of course at 

 a comparatively high level, and it is probable that they received water only 

 during the inundation. Linant Bey calculates the capacity of Lake McEris at 

 3,686,667 cubic yards and the water received by it at high Nile at 465 cubio 

 yards the second. 



