on Rivers and Canals . 
57i 
III. On the nature of rivers and flowing waters. 
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10. Rivers contain divers inherent caufes of the ac- 
celeration of their motion. 
1 ft, Their fprings are either in mountains or on high 
grounds, and it is by the defcent of the waters from thefe 
elevations that they acquire a velocity and acceleration of 
motion fufficient to fuftain and propagate it through the 
reft of their courfe. 
2dly, The cohefion of the particles of a fluid,, in a 
bed ever fo little inclined , is a fecond caufe of accelera- 
tion of motion in the fluid ; becaufe, by their mutual at- 
traction, thofe particles which begin firft to flow draw 
after them thofe which are contiguous, thefe the follow- 
ing, and fo on ad infinitum. 
3dly, Moreover, where a river, by flowing in a bed 
. 
nearly horizontal, has loft a great part of the velocity 
which it had acquired in the preceding declivities, and; 
the bed by this means is become large and lh allow, which* 
confequently again augments the flownefs of the cur- 
rent ; it may, however, recover a part of its velocity, 
even in the fame horizontal bed, by augmenting the 
depth thereof, and diminifhing its breadth; for by this 
means the weight of the fuperior waters upon the infe- 
7 
nor. 
