THE NILE DELTA. 65 



it yielded from year to year, from century to century, to the incessant action of 

 the stream. The whole delta thus becomes displaced from south to north, 

 according as the river beds are raised and the mouths extended seawards by the 

 accumulation of alluvial deposits. At present the Batn-el-Bagara fork is over 

 12 miles from Cairo, following the windings of the island- studded stream, and 

 has consequently been displaced at the annual rate of about 24 feet. Analogous 

 changes have taken place throughout the whole of the delta, where the current 

 has eaten its banks now to the right, now to the left, where simple channels have 

 become broad watercourses, while copious streams have disappeared or shifted their 

 beds. 



Under the influence of the mystic ideas prevalent regarding the value of 

 numbers, the old writers unanimously agreed to reckon seven chief branches in 

 the delta, all the others being regarded as " false mouths." At the same time the 

 normal direction of the streams required for irrigation purposes was carefully 

 maintained during peaceful epochs by incessant dredging, embankments, and works 

 of canalisation. It is now, however, no longer possible to trace the course of the 

 seven ancient branches, which, left to themselves, resumed their erratic tendencies, 

 shifting their beds with every fresh inimdation. But there is a general agree- 

 ment regarding their main direction, and many doubtful points of the hydrology 

 of the Nile as described by Herodotus and Strabo have been cleared up by the 

 naturalists of the French expedition to Egypt at the close of the last century. 



At present two main branches only are enumerated, and these are indicated on 

 the convex curve of the seaboard by two points formed by the tongues of alluvial 

 land advancing continually seawards. They are the Rashid or Rosetta branch, 

 identified with the Bolbitinis of the ancients, and that of Damietta, which 

 formerly bore the names of Phatnetica and Bucolica. The Rosetta branch, some 14 

 miles the shorter of the two, but flowing in a bed from 30 to 50 inches lower, 

 carries ofE the largest quantity of water, leaving not more than four-ninths to 

 that of Damietta and the intermediate Menufieh channel.* Nevertheless the 

 Damietta River, thanks to its greater elevation, is much more available for 

 irrigation purposes. The two branches, diverging like the radii of a circle, flow 

 respectively north-west and north-east, advancing at their mouths some 5 miles 

 beyond the normal coast-line. But, like all rivers falling into the Mediterranean, 

 both are half closed by mud and sandbanks, barring the passage to large vessels. 

 The western or Rosetta River has two channels from 7 to 8 feet deep, while that 

 of Damietta, being less open, has a depth of scarcely 65 inches at its entrance. At 

 high water, when there is a discharge of 470,000 cubic feet per second, the bar 

 is reduced not more than 4 or 5 inches, its elevation depending more on the action 



* Discharge of the Nile at low water in 1875, according to Ali Pasha Mubarek : — 



Cubic feet. 



Rosetta branch 6,370 



Damietta „ 8,560 



Menufieh channel 670 



Total 15,600 



Mean 166,000 



5 — AF. 



