San Carlos a1 
Our boatmen continued to paddle all day, and as night 
approached redoubled their exertions, singing to the stroke 
of their paddles. I was astonished at their endurance. 
They kept on until eleven o’clock at night, when we reached 
San Carlos, having accomplished about thirty-five miles 
during the day against the current. San Carlos is at the head 
of the river, where it issues from the great lake of Nicaragua, 
about one hundred and twenty miles from Greytown. The 
mean level of the waters of the lake, according to the survey 
of Colonel O. W. Childs, in 1851, is 1074 feet, so that the 
river falls on an average a little less than one foot per mile. 
The height of the lowest pass between the lake and the 
Pacific is said to be twenty-six feet above the lake, therefore 
at that point the highest elevation between the two oceans is 
only about 133 feet; but even allowing that an error of a 
few feet may be discovered when a thorough survey is made 
across from sea to sea, there can be no doubt that at this 
point occurs the lowest pass between the Atlantic and the 
Pacific in Central America. This fact, and the immense 
natural reservoir of water near the head of the navigation, 
point out the route as a practicable one for a ship canal 
between the two oceans. 
Instead of cutting a canal from the head of the delta of 
the San Juan to the sea, as has been proposed, the Colorado 
branch might be straightened, and dredged to the required 
depth. Higher up, the Torre, Castillo, and Machuca Rapids 
form natural dams across the river. These might be raised, 
locks formed round them, and the water deepened by dredg- 
ing between them. In this way the great expense of cutting 
a canal, and the fearful mortality that always arises amongst 
the labourers when excavations are made in the virgin soil 
of the tropics, especially in marshy lands, would be greatly 
lessened between the lake and the Atlantic. Another great 
advantage would be that the deepening of the river could 
be effected by steam power, so that it would not be necessary 
to bring such a multitude of labourers to the isthmus as 
would be required if a canal were cut from the river; the 
whole track, moreover, passes through virgin forests rich in 
inexhaustible supplies of fuel.? 
1The commission appointed by the United States Government to 
examine into the practicability of making a canal across the isthmus 
