275 



of the Canal da Centre, (between Chalons and 

 Digoin), and of the Grand Junction canal, (be- 

 tween Brentford and Braunston) : the moun- 

 tains of the isthmus may be still more elevated, 

 and perhaps are divided by no transversal valley 

 from south to north. We think that more ad- 

 vantageous spots may be chosen ; but we ought 

 here to observe that the height of the ridge is 

 an inseparable obstacle to the junction of seas, 

 only, when there is not at the same time a suffi- 

 cient quantity of upper waters fit to be con- 

 veyed to the point of partition. Seven or eight 

 locks crowded together on the canals of Briare 

 and Languedoc and regulating falls of water 

 of from 64 to 70 feet, long appeared an extra- 

 ordinary work, notwithstanding the small di- 

 mension of the locks, and the depth of the 

 canals, of which the section does not exceed 

 5 to 6 feet. The Staircase of Neptune, in the 

 Caledonian canal, presents a similar accumu- 

 lation of locks, on a scale so much more exten- 

 sive, that frigates can rise in a small space of 

 time to the height of 60 feet. Now, that work 

 only cost 257,000 piastres, that is five times less 

 than three pits of the mine of Valenciana in 

 Mexico ; and ten Staircases of Neptune would 

 cause ships of 600 tons to pass over a ridge of 

 partition 600 feet higher than the chain of the 

 Corbieres, between the Mediterranean and the 



* Near Rogny and Fonseranne. 



