THE ISTHMUS OF PANAMA. 113 



who surveyed this route in 1781, makes the summit 

 level but one hundred and fifty-five feet above Lake 

 Nicaragua ; but I am not aware that his report has 

 ever been confirmed. 



The advocates of both these routes base their esti- 

 mates in a great measure upon the feasibility of con- 

 verting the San Juan river into a ship canal. By 

 some the practicability of this does not seem to be 

 doubted, but the trial will prove, if nothing else will, 

 that this is a very formidable stream to contend with. 

 We have no rivers in the United States that com- 

 # parew T ith those of Central America in their devia- 

 tions from a given level, either in extent or rapidity 

 of their variations. It is no uncommon thing for a 

 stream of from two to three hundred yards in width, 

 to rise a foot an hour, for twelve or fifteen hours in 

 succession, and then decline as rapidly ; and during 

 the flood they bear down their swift currents im- 

 mense quantities of flood-wood, and sometimes the 

 largest trees of the forest. 



After the completion of the canal between Car- 

 thagena and the Magdalena river, in New Grenada, 

 the first flood swept away its lock, and yet this is an 

 ordinary canal, and merely communicates with the 

 river at its extremity. So confident were the state- 

 ments of those who might be presumed to know, of 

 the navigability of the River Chagres, that the Pan- 

 ama Railroad Company first intended to commence 

 the construction of that work between Gorgona and 

 Panama ; but they soon found it almost impossible 

 to reach Gorgona with their supplies. It is very 



