■200 Wisconsin Academy of Sciences^ Arts, arid Letters. 



and 1853, the celebrated hydraulic engineer Lombardini, pub- 

 lished a number of papers upon the hydraulic condition of the 

 river Po, in which he demonstrates that levees have not ele- 

 vated the bed of the river, although they have increased the 

 height of floods by retaining between the banks the waters 

 which before escaped through crevasses ; and this height has 

 been further increased by the more rapid flow caused by clear- 

 ing the mountain sides of their forests. lu 1841, M. SurelJ 

 published a paper upon the torrents of the Alps, showing that 

 forests exercise an miportant moderating effect, and advises 

 their cultivation for that purpose. In 184:3, M. de Buffon pub- 

 lished his theoretical and practical treatise upon irrigation. 

 He adopts de Prony's formula for the mean velocity with 

 Eytelwein's co-efficients. He thinks the float, from its sim- 

 plicity, is superior to all other instruments for measuring the 

 ■velocity. M. Weisbach in his mechanics, published at Frei- 

 berg in 1846, treats very fully of hydraulics, for which task 

 fthe special study of many years had peculiarly fitted him. 



M. Surrell, in 1847, published an elaborate work upon the 

 improvement of the river .Rhone. In 1818 appeared Dupuit's 

 work on hydraulics, which is a valuable contribution to the 

 science. This same year was published a memoir by M. 

 Baumgarten upon a portion of the Garonne, giving the 

 various works used in the improvement and discussing their 

 effects. He reports some very interesting experiments, among 

 others that of measurements upon the transverse section of 

 the water-surface at a nearly straight portion of the river 

 >(width about 600 feet), both when the water was rising and 

 fallino-. When rising, at the rate of about 5 feet in twenty- 

 four hours, with a maximum velocity of about 7 feet per 

 second, he found the water in the middle to be about 0.4 of a 

 foot above that on the right bank, and 0.1 above that on the 

 left. When falling at the rate of about 8 feet in twenty-four 

 hours, with a maximum velocity of about 7.5 feet per second, 

 the water-surface was sensibly a plane, being at the right 



