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river with a dam in the hope o£ creating a reservoir. At Wady Haifa, 
near the foot of the 2nd Cataract, a masonry gauge divided into 
metres has been erected and read since 1877. Its accidental zero is 
R.L. 116.69 and the mean low-water level, or true zero, is R.L. 117.89. 
Between the 1st and 2nd Cataracts, the Nile has a length of 345 kilo- 
metres and a slope of t 2 5 _ oo* The mean width of the river is 500 
metres, and the mean depths in flood and summer are 9 and 2 metres. 
The velocity in summer falls to 50 centimetres per second and rises to 
2 metres per second in flood. The river in this reach is generally 
within sandstone, and the greater part is provided with gigantic spurs 
on both banks. These spurs perform the double work of collecting 
soil on the sides in flood and training the river in summer. They were 
probably put up by the great Rameses 3,000 years ago, as some of the 
most massive of them have evidently been constructed to turn the 
river on a curve out of its natural channel on to the opposite side in order 
to secure deep water in front of Rameses’ temple of J erf Husain (“ Jerf ” 
means steep, scoured bank). The spurs have been constructed with 
care, and as the courses of roughly-dressed stone can be examined at 
fairly low water (I have never seen them at absolutely low water) it 
is evident that there has been no great degradation of the bed during 
the last 2,000 or 3,000 years. The first, or Assuan Cataract, has a 
drop of 5 metres on a length of 5 kilometres. 
From Khartoum to Assuan, on a total length of 1809 kilometres, 
there are 565 kilometres of so-called cataracts with a total drop of 192 
metres, and 1,244 kilometres of ordinary channel with a total drop of 
103 metres. 
At the head of the 1st Cataract is the Assu&n dam, regulated on for 
the first time in October 1902. It has 140 openings of 2 metres x 7 
metres and 40 openings of 2 metres x 3J metres. 
At the foot of the 1st Cataract, opposite the town of Assuan, on the 
Island of Elephantine, has stood a Nile gauge from very ancient times. 
An officer belonging to the Roman garrison in the time of the Emperor 
Severus marked an extraordinarily high flood on the gauge. The 
maximum flood-mark at the time of the visit of Napoleon’s French 
savants was however 2.11 metres higher than the above. As the 
middle of Severus’ reign was A.D. 200, and the visit of French savants 
A. D. 1800, they concluded that the bed and banks of the Nile had 
risen 2.11 metres in 1600 years or 0.132 metres per 100 years. The 
new gauge divided into cubits and twenty-fourths was erected in 
