114 
MR. HORNER ON THE ALLUVIAL LAND OF EGYPT. 
above Cairo, and the distance between the two places by the Nile being 556 miles, 
the average fall of the river is little more than half a foot in a mile, viz. 0'54 ft. ; and 
Assouan being 365 feet above the Mediterranean, and 696 miles distant from it, the 
average fall of the Nile from the foot of the First Cataract to the sea is 0'524 ft. in a 
mile*. Russegger does not give the place in Cairo from which he measured the 
above 300 feet, but by the careful measurements of the French Brigade in 1847, 
before referred to, M. Talabot states the lowest water of the Nile in the Nilometer 
of Rhoda near Cairo in that year to have been 14‘08 metres, or 46 feet 2 inches above 
low-water mark of the Mediterranean at Tineh ; and the distance to the mouth of 
the Damietta branch, following the course of the river, being 149 miles, the average 
fall is thus only 3f inches in a mile. 
The Inundations of the Nile. 
The commencement of the rise of the Nile, immediately below Assouan, is about 
the summer solstice. The first rise at Cairo, indicated by an increasing motion in 
the stream, is usually in the first week of July. The rise is scarcely perceptible for 
six or eight days, and it then becomes more rapid. About the middle of August it 
has obtained two-thirds of the height between the lowest ebb and highest rise. At 
this period the water enters the great side branch on the left bank, the Bahr el Jusef, 
Joseph’s Canal, called also the Magrour, and now is the time when the artificial 
branches or canals are opened, the commencement of the inundation over the parched 
plains. The rise attains its maximum between the 20th and 30th of September, and 
this state of the inundation is called the Salihe. The water remains pretty stationary 
for fourteen days ; it then begins to fall, at first at a more rapid rate than that with 
which it rose, but after it has fallen one-half, the decrease is very gradual. About 
the 10th of November it has usually fallen one-half, and it goes sinking slowly until 
somewhat beyond the following May. The rise of the river continues therefore about 
ninety days (from 1st of July to 28th of Sept.), but it continues falling about 230 days 
(12th of October to end of May). The changes of level are well illustrated by the 
annexed diagram, given to M. Talabot in 1847 by Mougel Bey, the engineer for the 
Barrage of the Nile at the apex of the Delta. 
* Russeggek, Reisen, ii. 271. The fall of the Thames from Chertsey to Teddington Lock, a distance of 
13| miles, is nearly 17^ inches in a mile. See Rennie, Report to the British Association in 1834, p. 487. 
“ Colonel Catjtley, the projector of the Ganges Canal (recently constructed), decided after careful thought 
and due regard to the experience gained on canals previously opened, that a fall of fifteen inches in every mile 
of length would best secure the desired ends.” — Short Account of the Ganges Canal, p. 7. 
