21 
sion works of extraordinary magnitude. It would be neces¬ 
sary to excavate a considerable portion of it to a depth much 
greater than has been hitherto customary in works of this kind 
and throughout more than 3J miles it would be indispensable 
to bore the mountains, and open a tunnel of sufficient dimen¬ 
sions to admit the large vessels employed in transatlantic navi¬ 
gation. The impossibility of attaining such an object we have 
already shewn above, in speaking of the proposed tunnel at Pa¬ 
nama, especially if the nucleus of the chain to be pierced through 
consists, as well as the Andes of which it forms a part, of gra¬ 
nite or ancient porphyry, as there is every reason to believe 
notwithstanding the superficial experiments made by Bailey. 
On the side of the Atlantic the port of San Juan de Nicara¬ 
gua, into which the river San Juan empties itself over a bar 
with only 3 feet water upon it, now only affords anchorage for 
a few vessels drawing 10 feet water; and could not be formed 
into a harbour for large ships except at an enormous expense. 
The port of St. John south, which would be reached on the 
Pacific side, is not adequate from its very small dimensions to 
the required object, and moreover it appears that with the 
prevailing north and north-east winds its access is not only 
difficult but even dangerous. 
In the isthmus of Tehuantepec, the greater part of the dis¬ 
tance which separates the two seas is occupied on the south by 
lagoons and extensive plains, and on the north it is traversed 
by the river Coatzacoalcos; so that the principal works to be 
executed would be comprised within a space of about 50 miles 
in length. 
The present project is the formation of a Ship Canal calcu¬ 
lated for the passage of vessels drawing 20 feet water ; it will 
have excellent ports at its extremities; and the materials for 
construction cannot be more abundant, superior in quality, or 
better distributed. A climate remarkable for its salubrity fa¬ 
vours also the isthmus of Tehuantepec, and the departments 
of which it forms a part, number a population of seven hundred 
and fifty thousand inhabitants. 
The admirable fertility of the soil, and the abundance of cat¬ 
tle and resources of all descriptions would enable the vessels 
