164 THE NICARAGUA CANAL. 
United States in the construction of a canal by way of 
lake Nicaragua and the river San Juan, but with no 
satisfactory results. In the same year Mexico caused a 
rough survey to be made of the line via the Coatacoalcos 
river and the isthmus of Tehuantepec, resulting in an 
official report that the ‘‘ canalization of this isthmus 
was problematical and gigantic.” 
Later, in 1828-29, a survey was made under orders 
from General Bolivar of a line substantially the same as 
that of the present railway between Aspinwall and 
Panama. Nothing was effected by this action, except 
to put an end to the popular error that the mean levels 
of the oceans on opposite sides of the isthmus differed 
appreciably. There are still some, I believe, among 
those who have not given their attention to this subject, 
' who are yet ignorant that differences are caused only by 
tides, winds. barometic pressures, and other temporary 
disturbing causes, and that the mean levels of the two 
seas may be regarded as practically the same. 
Many other attempts were made in the ensuing years, 
and with uniform lack of success. In 1830 the Nether- 
lands, beginning fairly enough, were obliged by the revo- 
lution in Belgium and its separation from Holland to 
give up the project. In 1835 President Jackson ap- 
pointed Mr. Charles Biddle as special agent to promote 
the idea of an isthmus canal, and to visit the Central 
American countries for that purpose. Mr. Biddle met 
with many difficulties, and returned to the United States 
with nothing accomplished of value, and from this time 
the projects became too numerous to be even touched 
upon in a paper of this scope. M. Guizot, under Louis 
Philippe, urges interoceanic canal questions upon the 
attention of the Chambers of Deputies. A bishop of San 
Salvador goes to Rome and urges the importance of a 
canal upon the Pope. All of no avail; but in 1849 a suc- 
cess is scored, not for a canal, but for the Panama rail- 
48 
