178 HISTORY OF 



to continue for some days ; which it would not 

 otherwise do, if, as soon as the cause was discon- 

 tinued, it acquired its former rapidity. 



A violent storm, that sets directly up against 

 the course of the stream, will always retard, and 

 sometimes entirely stop its course. I have seen 

 an instance of this, when the bed of a large river 

 was left entirely dry for some hours, and fish 

 were caught among the stones at the bottom. 



Inundations are generally greater towards the 

 source of rivers, than farther down ; because the 

 current is generally swifter below than above ; 

 and that for the reasons already assigned. 



A little river * may be received into a large 

 one, without augmenting either its width or depth. 

 This, which at first view seems a paradox, is yet 

 very easily accounted for. The little river, in 

 this case, only goes towards increasing the swift- 

 ness of the larger, and putting its dormant waters 

 into motion. In this manner, the Venetian 

 branch of the Po was pushed on by the Ferrarese 

 branch and that of Panaro, without any enlarge- 

 ment of its breadth or depth from these acces- 

 sions. 



A river tending to enter another, either perpen- 

 dicularly or in an opposite direction, will be di- 

 verted, by degrees, from that direction ; and be 

 obliged to make itself a more favourable entrance 

 downward, and more conspiring with the stream 

 of the former. 



The union of two rivers into one, makes it flow 

 the swifter ; since the same quantity of water, 



* Guglieltnini della Natura de Fiumi, 



