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period of six weeks permits of the thorough saturation of the subsoil 
in places where the subsoil is of proper consistency ; and this water 
can be drawn on, in winter and summer, for maturing certain crops 
and growing others. It was where the subsoil gave a plentiful supply 
of water, and permitted of intense cultivation throughout the year, 
that we find all the ancient capitals of Egypt. Abydos has the finest 
subsoil water in the Nile Valley ; Memphis has an excellent supply ; 
while Thebes has the only good subsoil water on the whole of the 
right bank. Good subsoil water was to the ancient Egyptian world 
what the presence of a rich gold mine is to one of our new colonies. 
Subsoil water supplies the link between basin and perennial irrigation. 
It explains the reason why modern Egypt is not satisfied with the 
irrigation which has come down from the remotest antiquity, but is 
desirous of conferring on the length and breadth of the Nile Valley 
those advantages which gave Abydos, Memphis, and Thebes their 
pre-eminence in the past. Any country which possesses rivers and 
streams whose waters are in flood for six weeks per annum at a suitable 
season of the year can betake itself to basin irrigation with more or 
less profit. The science of dams, weirs, and regulators has received 
such development during recent years that there can be no problem 
so difficult that it cannot be solved by experience and originality. 
Basin irrigation allows of the thorough development of countries whose 
streams have short and turbid floods which precede a fairly cool 
season ; whether such irrigation be the stately irrigation of the Nile 
Valley, perfected by the science and experience of 7,000 years ; or the 
less perfect, but still highly developed and river-fed tank systems of 
Madras ; or the primitive, but effective basins of Bundelkund, where 
the impounded water irrigates the crops on the down-stream sides of 
the basins for one season, and then allows of the basins themselves 
being dried and cultivated in the next. 
The Nile in high flood rises 10 metres above its bed, in a mean 
flood 9 metres and in a poor flood 7 \ metres. The beds of the main 
basin canals are about 4 metres, and the cultivated land at the river’s 
edge about 9 metres above the river-bed. The basins have an average 
area of 7,000 acres. Where the valley is narrow, they average 2,000 
acres each, and where it is wide 20,000 acres; while some of the tail 
basins are 40,000 acres in extent. Each canal has about seven or 
eight basins depending on it, of which the last is always the largest. 
There are masonry regulators at the canal heads, at each crossing of 
