312 M. P.S. GirarS on Navigable Canals* 



weight in the descending boals over those which ascend, 

 a part of the vohinfie of water necessary for the navigation 

 may be raised from each of the two rivers where the canal 

 terminates, to the reservoir on the summit level. This re- 

 servoir would thus be supplied so much the more abundant- 

 ly as the navigation became more active ; this is the most 

 useful result that we can hope to obtain. 



Among all the points of the kingdom where so advanta- 

 geous communications might be opened, I will point out, 

 for example, the plateau of St. Etienne in the department 

 of the Loire. An interesting memoir of M. Beaunier, En- 

 gineer in Chief of Mines, shews that this plateau furrishes 

 aniiuailv 300,000 tons ofpit-coals, which descend to the basin 

 of the Loire on the one side, and to the basin of the Rhone on 

 the other. Now which ever way these coals descend, it is 

 certain that their transportations on a navigable canal, es- 

 tablished according to our principles, might not only render 

 null the expense of water from its summit level, but might 

 even raise a certain portion of water to the reservoir on 

 that level from the lower levels. 



The memoir of M. Beaunier furnishes the fundamental 

 data of the project of communication between the Rhone 

 and the Loire. These two rivers are but 54 Kilometres, 

 or 10 leagues distant from each other in this place, 15 ki- 

 lometres of which are already navigable on the Canal de 

 Givors, which extends from Givors to Rive de Gier. The 

 idea of uniting the ocean to the Mediterranean by this route 

 is already very old. But.what would especially character- 

 ize this communication over the plateau of St. Etienne, is 

 that we there should find in the mass itself of heavy arti- 

 cles in which that section of country abounds, a part of the 

 force necessary for their transportation, since in descending 

 along the canal which served for their exportation they 

 might raise from the lower to the higher levels, a portion 

 of the water necessary for the supply of the canal. This is 

 one of the cases where it becomes as it were indifferent 

 whether we have a determined body of water in reserve, 

 on the summit level of a canal, or are able to ship on this 

 level an equal quantity of solid matter ; this is an imme- 

 diate consequence of our new theory, and one of the 

 most remarkable ones which it furnishes. 



After having thus pointed out the advantages of this new 

 theory, let us give a moment's attention to demonstrate the 



