Large works of this nature, while they create an inconceivable development of commerce, must have a certain amount of a trading population to begin upon. A gold-beater can cover the effigy of a man on horseback with a sovereign; but he must have the sovereign first. It was not merely because the full power of the iron rail to facilitate the transition of heavy burdens had not been estimated, and because no Stephenson had constructed a "Rocket engine," that a railway with steam locomotives was not made from London to Liverpool before 1836. Until the intermediate traffic between these termini had swelled to a sufficient amount in quantity and value to bear reimbursement for establishing such a mode of conveyance, its execution would have been impossible, even though men had known how to set about it. What has been the condition of the countries under consideration? In 1839, the entire population of the tropical American isthmus, in the states of central America and New Grenada did not exceed three millions. The number of the inhabitants of pure European descent did not exceed one hundred thousand. It was only among this inconsiderable fraction that any thing like wealth, intelligence, and enterprise, akin to that of Europe, was to be found; the rest were poor and ignorant aboriginals and mixed races, in a state of scarcely demi-civilization. Throughout this thinly-peopled and poverty-stricken region, there was neither law nor government. In Stephens's "Central America," may be found an amusing account of a hunt after a government, by a luckless American diplomatist, who had been sent to seek for one in central America. A night wanderer running through bog and brake after a will-o'-the-wisp, could not have encountered more perils, or in search of a more impalpable phantom. In short, there was nobody to trade with. To the south of the isthmus, along the Pacific coast of America, there was only one station to which merchants could resort with any fair prospect of gain--Valparaiso. Except Chili, all the Pacific states of South America were retrograding from a very imperfect civilization, under a succession of petty and aimless revolutions. To the north of the isthmus matters were little, if any thing better. Mexico had gone backward from the time of its revolution; and, at the best, its commerce in the Pacific had been confined to a yearly ship between Acapulco and the Philippines. Throughout California and Oregon, with the exception of a few European and half-breed members, there were none but savage aboriginal tribes. The Russian settlements in the far north had nothing but a paltry trade in furs with Kamschatka, that barely defrayed its own expenses. Neither was there any encouragement to make a short cut to the innumerable islands of the Pacific. The whole of Polynesia lay outside of the pale of civilization. In Tahiti, the Sandwich group, and the northern peninsula of New Zealand, missionaries had barely sowed the first seeds