412 
DEPOSITS OF THE KILE. 
The Nile is larger than all the rivers of Lombardy to¬ 
gether/ it drains a basin twenty times as extensive, its banks 
have been occupied by man probably twice as long. But its 
geographical character has not been much changed in the 
whole period of recorded history, and, though its outlets have 
somewhat fluctuated in number and position, its historically 
known encroachments upon the sea are trifling compared with 
those of the Po and the neighboring streams. The deposits of 
the Nile are naturally greater in Upper than in Lower Egypt. 
They are found to have raised the soil at Thebes about seven 
feet within the last seventeen hundred years, and in the Delta 
the rise has been certainly more than half as great. 
We shall, therefore, not exceed the truth if we suppose the 
annually inundated surface of Egypt to have been elevated, 
upon an average, ten feet, within the last 5,000 years, or twice 
and a half the period during which the history of the Po is 
known to us.f 
We may estimate the present actually cultivated area of 
Egypt at about 5,500 square statute miles. As I have com¬ 
puted in a note on page 372, that area is not more than half 
as extensive as under the dynasties of the Pharaohs and the 
Ptolemies; for—though, in consequence of the elevation of 
the river bed, the inundations now have a wider natural 
spread—the industry of the ancient Egyptians conducted the 
* From daily measurements during a period of fourteen years—1827 to 
1840—the mean delivery of the Po at Ponte Lagoscuro, below the entrance 
of its last tributary, is found to he 1,720 cubic metres, or 60,745 cubic feet, 
per second. Its smallest delivery is 186 cubic metres, or 6,569 cubic feet, 
its greatest 5,156 cubic metres, or 182,094 cubic feet.— Baumgakten, follow¬ 
ing Lombakdini, volume before cited, p. 159. 
The average delivery of the Nile being 101,000 cubic feet per second, it 
follows that the Po contributes to the Adriatic six tenths as much water as 
the Nile to the Mediterranean—a result which will surprise most readers. 
t We are quite safe in supposing that the valley of the Nile has been 
occupied by man at least 5,000 years. The dates of Egyptian chronology 
are uncertain, but I believe no inquirer estimates the age of the great pyra¬ 
mids at less than forty centuries, and the construction of such works im¬ 
plies an already ancient civilization. 
