DELTA OF THE NILE. 357 



ing the clearings on the southern side of the Alps, was 

 performed between the thirteenth and the seventeenth 

 centuries. Since, then, the mouth of the river has 

 advanced with great rapidity into the bosom of the 

 Adriatic. The embankment has not only increased 

 the amount of materials carried by the Po towards 

 the sea, but is continually raising the bed of the 

 river, which is actually above the level of the houses 

 of Ferrara. 



Similar causes have produced similar effects in the 

 case of the Mississippi, since human industiy has 

 taken possession of the vast region through which 

 this river and its tributaries flow. 



2. Egypt, according to Herodotus, a present from the NUe. 



The Egyptians, more intelligent than ourselves, 

 take the greatest pains to store up the waters of the 

 Nile, by means of dams, at each period of flood. 

 They receive them in canals, so as to distribute them 

 more completely over the soil. By this means they 

 also diminish the force of the current, and generally 

 succeed in mitigating the otherwise disastrous effects 

 of the inundation. The mud, which would under 

 other circumstances be carried to the sea, is depo- 

 sited on its way, and fertilises the soil ; the materials 

 which would form the delta are spread over the 



