248 



of being heavily laden, natural or artificial 

 passes, of the mean depth of from 15 to 17 feet, 

 and an uninterrupted navigation, requiring no 

 unloading of the vessels. These conditions are 

 indispensable, and it would be changing the 

 question to confound the canals which, by their 

 dimensions, serve only to facilitate inland com- 

 munications, and a coasting trade (like the 

 canals of Languedoc and the Clyde, between 

 the Mediterranean and the Atlantic Ocean, or 

 between the Irish and North Seas), with basins 

 and locks capable of receiving the ships em- 

 ployed in the trade of Canton. In a matter that 

 interests every nation which has made some pro- 

 gress in civilization, greater precision should be 

 used than has hitherto been done, respecting a 

 problem, the successful application of which de- 

 pends principally on the choice of the localities. 

 It would be imprudent, I here repeat, to begin 

 at one point without having examined and 

 levelled ^tners ; and it would be above all to 

 be regretted if the works were undertaken 

 on too small a scale ; for in works of this de- 

 scription the expence does not augment in pro- 

 portion to the section of the canals, or the 

 breadth of the water channel. 



The erroneous idea which geographers, or 

 rather drawers of maps, have so long propa- 

 gated of the equal heights of the Cordilleras of 

 America, their prolongation in the form of 



