4^2 FOURTH REPORT — 1834. 



similar experiments on the s.ime river, both in cahii and windy 

 weather : the maximum velocity was then found to be equal to 

 the velocity at the surface; but when the surface was affected by 

 winds, the acceleration was greater or less. 



M. Raucoiirt's experiments have been partially tried by 

 Messrs. Detrem and Henry ; the latter made the relation be- 

 tween the mean and superficial velocities in the proportion of 

 0-715 to 0-903, and the product of the Neva 116,000 cubic feet 

 (English measure) per second : the maximum velocity diminished 

 from the upper to the lower part of the river from 1-79 metres 

 to 1*015 metres. The inclination per thoiisand metres was found 

 to be 0-0267 *. 



But the most important observations which have been made 

 on rivers in modern times are those of M. De Fontaine on the 

 river Rhine and its affluents. 



Having been entrusted with the execution of certain works in 

 the year 1820, for the purpose of restraining and regulating the 

 course of that part of the river which adjoins the French territory, 

 M. De Fontaine felt it his duty to investigate the phenomena 

 exhibited by that river in different parts of its course, and the 

 result has been the publication (in the j'ear 1833) of his obser- 

 vations in detail, in a work, entitled, Travaiix du Rhine. 

 According to M. De Fontaine, the river Rhine derives its origin 

 from the glaciers of St. Gothard, in Switzerland, whence the 

 waters run by three principal affluents to Reichenau, where they 

 \mite into one great river ; after being increased by munerous 

 torrents from the Alps, it empties itself into the Lake of Con- 

 stance, out of which it passes to be precipitated over the falls of 

 Schaffhausen and Lauffen, and, after having received by means of 

 the river Aar jths of the waters of Switzerland, passes through 

 the great valley which separates the mountains of the Vosges 

 from those of the Black Forest ; thence It passes through the 

 narrow defiles of Blngen, thence through Holland, after which 

 it divides Itself Into several branches (to one of which It gives 

 its name), and empties itself into the German Sea above Ley den. 

 In Its course it receives many considerable affluents, such as the 

 Elser, the Klnzlg, the 111, the Moder, and the Murg on the 

 French boundary, and the Moselle, Mayne, Meuse, and others 

 as It approaches the sea ; It communicates with the Zuyder Zee 

 by means of the Isel. The irregularity of its course and the 



• Journal des Voies de Communication, 8vo, 1826, St. Petersburgh • " Sur le 

 Jaugeages de la Neva at de ses differens bras." 



f Des Travaux du Fleuve dti Rhlii : par A. J. C. De Fontaine, Ing^nieur en 

 cbef de premiere Classe des Fonts et Chauss4es. 



