466 FOURTH REPORT — 1334. 



Tlie volume of water which passes, 

 At Basle, 



Cub. Met. 



Dui'ing great floods is equal to 4624 



During mean water do. 865 



During very low water .... do. 330 



At Vieux Brisach, 



During great floods is equal to 4630 



During mean water do. 885 



During very low water .... do. 340 



At Kehl, 



During great floods is equal to 4685 



During mean water do. 956 



During low water do. 380 



At Lauterbourg, 



During great floods is equal to 5010 



During mean water do. 1106 



During low water do. 465 



From which it results, that the volume of water which passes 

 per second during great floods, compared with the volume which 

 passes during the lowest waters, varies fi'om 10 to 1, to 14 to 1 ; 

 and in comparison of the mean to the low water, from 4^^ to 1, 

 and 5^ to 1. 



The remaining and indeed principal part of M. de Fontaine's 

 report is devoted to an account of the artificial woi*ks which have 

 been undertaken for the purpose of regulating the course of the 

 Rhine, in which the various kinds of fascines, embankments, 

 dams, jetties, counterforts, cuts, short channels, and the modes 

 of defending the banks are all spoken of in detail. 



The principles which have guided him in the execution of 

 these works are, — 



1st, The union of the waters into one channel, and the closing 

 of the secondary branches ; 



2ndly, The avoidance of all rectilinear cuts, and the adoption 

 of proper curves derived from observations on the rivers them- 

 selves ; 



3rdly, The formation of proper channels corresponding to the 

 different volumes and velocities of the waters ; 



In the first case, the practice of the engineer mu&t be governed 

 by the volume and velocity of the waters and the nature of the 

 soil: 



In the second, by the resistance of the soil : 



