614 Aft*. mann’s TreatiSe 
is farther from the bottom and fides thereof, than it is in 
the feparate beds. All thefe caufes, in proportion to their 
refpedtive quantities, contribute to accelerate the velocity 
of the common ftream. 
50. It is not lefs certain, that in rivers which bring 
down a great abundance of water, the more the velocity 
and difcharge thereof at their mouths are retarded and 
dim ini fixed by the tides, the winds, the rolling in of the 
fea, See. the more will the back-waters increafe in height, 
and endanger overflowing, the inner parts of the coun- 
try. This is evident, becaufe the decreafe of velocity in 
the current, and the increafe of height of all the back- 
waters that are affedted thereby, are in a reciprocal in- 
verfe ratio one of another (fee above N.° 32.). 
Nature itfelf teaches us a method of preventing, or at 
leaft of dimini Axing, this effect. We fee all great rivers 
overcharged with a vaft volume of water divide, when 
they come near the fea,. into different branches and 
mouths, whereby the fuper-abundance of their waters is 
difeharged. This is the cafe with the Scheld, the Rhine,. 
the Rhone, the Po, the Danube, the W olga, the Euphrates, 
/ 
thelndus, the Ganges, the Nile, the Niger, the Oroonoko,. 
the River of Amazons, and with almofl; all other great; 
livers. 
7 
This 
