posed for the
communication between the two seas, such as the Province of Nicaragua,
the Isthmus of Tehuantepec, &c.; but invincible obstacles occur in all
those localities, while on the contrary the Isthmus of Panama is
beyond doubt the most favorable point, according to the opinion of all
the scientific and practical men who have visited that part of the new
world.[3] We shall proceed, therefore, to describe that Isthmus as
far as is necessary for the present purpose.

The Isthmus of Panama[4] may be considered as extending from the
Meridian of 77 deg. to that of 81 deg. W. of Greenwich. Its breadth at the
narrowest point, opposite to the city of Panama, is about thirty
miles. The general feature of the Isthmus on the map is that of an
arc, or bow, the chord of which lies nearly east and west. It now
forms a province of the republic of New Granada.

It may appear strange, yet it is now well known to be the fact, that
although the small width of the Isthmus was ascertained soon after the
discovery of America, its natural features remained entirely unknown
for three hundred years. Robertson, in his History of America, states
that the Isthmus is traversed in all its length by a range of high
mountains, and it was reserved for our scientific countryman, Lloyd,
who surveyed the Isthmus in 1828 and 1829, by direction of Bolivar,
then president of the Republic of Colombia, to dispel the illusion.
From his observations, confirmed by more recent travellers, it is now
ascertained that the chain of the Andes terminates near Porto Bello to
the east of the Bay of Limon, otherwise called Navy Bay, and that the
Isthmus is, in this part, throughout its whole width, a flat country.
It was also long supposed that there was an enormous difference
between the rise and fall of the tide in the Pacific and Atlantic
Oceans on either side of the Isthmus, and that the opening of a
communication between the two seas would be productive of danger to a
large portion of the American continent. It is now, however,
ascertained that the difference of altitude is very trifling, not more
than thirteen feet at high water.[5] The prevalence of these errors
may have tended, in combination with Spanish jealousy, unhealthiness
of climate on the Atlantic side, the denseness of the forests, and the
unsettled state of the Government for some years after the Spanish
yoke was shaken off, to prevent the undertaking now proposed from
being seriously considered.