

390 



the bottom. By this process, the bed or channel of the 

 river becomes more and more elevated, until there is 

 no longer any descent, and the capacity of the channel 

 is insufficient to retain its waters. Hence, in common 

 tides, a considerable reflux : but in violent storms, or 

 gales of wind, a reflux that overflows the surrounding 

 country, causing disruptions of its banks at some point 

 or points, that will afford a descent of its waters into 

 the sea. 



This has been, and will continue to be universally 

 the case with all rivers, whose point of discharge has 

 been extended into a bay, or gulf, beyond that of their 

 original or primitive efflux. 



This has been one of the principal agents in the 

 formation and extension of the deltas of the Po, the 

 Indus, the Ganges, and the Nile ; and also in the fre- 

 quent disruptions of their banks, thereby forming low 

 sunken places, or lagoons of stagnant waters, the 

 never-failing sources of pestilence and disease, among 

 the innocent and unsuspecting inhabitants who may be 

 situated within reach of their poisonous exhalations. 



It was by this cause that the bed of the Nile was 

 elevated so far above the adjacent vallies, that it be- 

 came necessary to attend with the greatest diligence, 

 to preserve the banks in repair, lest, by the force of the 

 waters, a breach should be made, and the whole coun- 

 try be inundated.* And it is this which may be said to 

 be in full operation, at this time, on the Mississippi, at 



* See remarks on the delta of the Po, Indus, and Nile, chap. ,13. 



