DIKES OF THE NILE. 517 
The object of the dikes of the Po, and, with few exceptions, 
of those of other European rivers, has always been to confine 
the waters of floods and the solid material transported by them 
within as narrow a channel as possible, and entirely to pre- 
vent them from flowing over the adjacent plains. The object 
of the Egyptian dikes and canals is the reverse, namely, to 
diffuse the swelling waters and their sediment over as wide a 
surface as possible, to store them up until the soil they cover has 
been thoroughly saturated and enriched, and then to conduct 
them over other grounds requiring a longer or a second submer- 
sion, and, in general, to suffer none of the precious fluid to escape 
except by evaporation and infiltration. 
Lake Moeris, whether wholly an artificial excavation, or a 
natural basin converted by embankments into a reservoir, was 
designed chiefly for the same purpose as the barrage built by 
Mougel Bey across the two great arms which enclose the Delta, 
namely, as a magazine to furnish a perennial supply of water 
to the thirsty soil. But these artificial arrangements alone did 
not suffice. Canals were dug to receive the water at lower 
stages of the river and conduct it far into the interior, and as 
all this was still not enough, hundreds of thousands of wells 
were sunk to bring up from the subsoil, and spread over the 
surface, the water which, by means of infiltration from the 
river-bed, pervades the inferior strata of the whole valley.* 
If asystem of lofty continuous dikes, like those of the Po, 
had really been adopted in Egypt, in the early dynasties when 
the power and the will to undertake the most stupendous ma- 
terial enterprises were so eminently characteristic of the gov- 
from a secular rise of the coast, rendered necessary some change in the 
hydraulic arrangements of Egypt. Mehemet Ali was advised to adopt a sys- 
tem of longitudinal levées, and he embanked the river from Jebel Silsileh to 
the sea with dikes six or seven feet high and twenty feet thick. Similar em- 
bankments were made around the Delta. These dikes are provided with 
transverse embankments, with sluices for admitting and canals for distributing 
the water, and they serve rather to retain the water and control its flow than 
to exclude it.—CLoT Bry, Aperceu sur ? Kgypte, ii., 437, 
* Tt is said that in the Delta alone 50,000 wells are employed for irrigation, 
