REPORT ON HYDRAULICS. — PART II. 443 



The author gives several practical rules relative to the junc- 

 tion of and derivations from rivers, whether with each other or 

 with the sea ; and, in the fourth section of his treatise, he de- 

 tails a series of experiments to determine the different velocities 

 of the same floating body, moved uniformly by an equal force 

 in different depths of water, the results of which are, that the 

 different velocities of the floating bodies are in an inverse ratio 

 of the respective depths of the water in which they float with an 

 equal impulsive force. 



The author gives the declivities of several rivers in France and 

 in Flanders, such as 





The Seine, from Paris to Havre, which he states to be 



The Loire 



The Rhone, from Besangon to the Mediterranean, ^ 



stated to be one of the most rapid in the world, I j 



or double of the mean declivity of the rivers in [ 2^2 o* 



Flanders J 



The Ypres in Flanders to Newport j-jbo- 



The Lys and Scheldt Wt'^* 



i_ _ 



TGo^O* 



The canals 



