History of the Science of Hydraulics. 199^ 



chutes to confine the river to a single channel ; and second, con- 

 verting all straight lines to curved in the river's course. His 

 reason for the latter plan is that in a bend the caving is limit- 

 ed to one bank, and can be more easily prevented than in a 

 double line of defensive works on a straight line. The dimen- 

 sions of the levees are far greater than those of the Mississip- 

 pi. Thev are 10 feet thick at top, with a slope of one upon 

 two towards the river and one upon one and a half toward 

 the land. The height is calculated to be a foot and a half 

 above the highest floods. Even the large levees are not con- 

 sidered sufficient. Strips of grass-land are left en both sides 

 6 1-2 feet wide on the exterior and 3 1-2 feet on the interior, 

 measuring from the foot of the slope of the levee. On the 

 outer edges of these strips are planted willows and poplars. 

 To guard against filtration when the levees are more than 7 

 feet high a banquette 'n added. Here and there when the 

 current of the river would be liable to act upon the levees, 

 large and strong traverses at distances of 600 to 1000 feet 

 apart are placed and protected, if need be, by fascines, to break 

 the force of the current. 



In 1834 appeared the first edition, and in 1810 the second 

 edition of a general treatise on hydraulics by D'Aubuisson de 

 Voisins. In 1835, M. Destrem published the result of a care- 

 fully conducted gauging of the Neva and its various branches, 

 under his immediate supervision. In the same year appeared 

 a historical sketch of the progress of hydraulics by Charles S. 

 Storrow, Boston, giving the demonstrations and practical ap- 

 plications of various formuhe proposed by different writers on 

 hydraulics. In 1836, Tredgold published Smeaton's experi- 

 mental papers on the power of water and wind to turn mills \ 

 Venturi's experiments on the motion of fluids (1798); and 

 Dr. Young's summary of practical hydraulics, chiefly from the 

 German of Eytelwein, In 1840, M. Dausse obtained* a pre- 

 mium for a paper upon the best methods of improving the 

 navigation of the principal rivers of France. Between 184S 



