Without entering further into the obstacles which present themselves to the formation of a canal along any one of the lines alluded to, I shall at once come to the conclusion, that for all the practical purposes of commercial intercourse which the physical circumstances of the country allow, a railroad is preferable, and may be constructed at infinitely less expense.  This position once established, the question next to be asked is, which is the most eligible spot for the work proposed?  On a careful examination of the relative merits of the several lines pointed out, that of the isthmus of Panama unquestionably appears to be the most eligible.  From its central position, and the short distance intervening between the two oceans, it seems, indeed, to be providentially destined to become the connecting link between the eastern and western worlds; and hence its being made a thoroughfare for all nations, must be a subject of the utmost importance to those engaged in commerce.

Some of our most eminent public writers of the day, anticipating the advantages likely to result from the emancipation of Spanish America, considered the opening of a passage across that isthmus as one of the mightiest events which could present itself to the enterprise of man; and it is well known, that during Mr Pitt’s administration projects on this subject were submitted to him—­some of them even attempting to show the feasibility of cutting a canal across, sufficiently deep and wide to admit vessels of the largest class.  Report says, that the minister frequently spoke in rapturous terms on the supposed facilities of this grand project; and it is believed, that the sanguine hopes of its realization had great weight with him when forming his plans for the independence of the southern division of the New World.  The same idea prevailed in Europe for the greater part of the last century; but yet no survey was instituted—­no steps taken to obtain correct data on the subject.  Humboldt revived it; and yet this great and beneficial scheme again remained neglected, and, to all appearance, forgotten.  At length the possession of the Marquesas islands by the French, brought the topic into public notice, when, towards the close of last April, and while submitting the project of a law to the Chamber of Deputies for a grant of money to cover the expenses of a government establishment in the new settlements, Admiral Roussin expressed himself thus:—­“The advantages of our new establishments, incontestable as they are even at present, will assume a far greater importance hereafter.  They will become of great value, should a plan which, at the present moment, fixes the attention of all maritime nations, be realized, namely, to open, through the isthmus of Panama, a passage between Europe and the Pacific, instead of going round by Cape Horn.  When this great event, alike interesting to all naval powers, shall have been effected, the Society and Marquesas islands, by being brought so much nearer to France, will take a prominent place among the most important stations of the world.  The facility of this communication will necessarily give a new activity to the navigation of the Pacific ocean; since this way will be, if not the shortest to the Indian and Chinese seas, certainly the safest, and, in a commercial point of view, unquestionably the most important.”