I shall have occasion hereafter to speak of the portage between the river Tapajos (one of the southern confluents of the Amazon) and the headwaters of the Rio de la Plata. This gives another immense inland navigation.

The mind is confused with the great images presented to it by the contemplation of these things. We have here a continent divided into many islands, (for most of its great streams inosculate,) whose shores produce, or may be made to produce, all that the earth gives for the maintenance of more people than the earth now holds. We have also here a fluvial navigation for large vessels, by the Amazon and its great tributaries, of (in round numbers) about six thousand miles, which does not include the innumerable small streams that empty into the Amazon, and which would probably swell the amount to ten thousand; neither does it include the Oronoco, with its tributaries, on the one hand, nor the La Plata, with its tributaries, upon the other; the former of which communicates with the valley of the Amazon by the Cassiquiari, and the latter merely requires a canal of six leagues in length, over very practicable ground, to do the same.

Let us now suppose the banks of these streams settled by an active and industrious population, desirous to exchange the rich products of their lands for the commodities and luxuries of foreign countries; let us suppose introduced into such a country the railroad and the steamboat, the plough, the axe, and the hoe; let us suppose the land divided into large estates, and cultivated by slave labor, so as to produce all that they are capable of producing: and with these considerations, we shall have no difficulty in coming to the conclusion that no territory on the face of the globe is so favorably situated, and that, if trade there is once awakened, the power, the wealth, and grandeur of ancient Babylon and modern London must yield to that of the depots of this trade, that shall be established at the mouths of the Oronoco, the Amazon, and the La Plata.

Humboldt, by far the greatest cosmographer that the world has yet known, and one of the most learned men and profoundest thinkers of any time, in contemplating the connexion between the valleys of the Oronoco and the Amazon by the Cassiquiari, speaks thus of its future importance:

"Since my departure from the banks of the Oronoco and the Amazon, a new era unfolds itself in the social state of the nations of the West. The fury of civil discussions will be succeeded by the blessings of peace and a freer development of the arts of industry. The bifurcation of the Oronoco," (the Cassiquiari,) "the isthmus of Tuamini," (my portage of Pimichim,) "so easy to pass over by an artificial canal, will fix the attention of commercial Europe. The Cassiquiari—as broad as the Rhine, and the course of which is one hundred and eighty miles in length—will no longer form in vain a navigable canal between two basins of rivers, which have a surface of one hundred and ninety thousand square leagues. The grain of New Grenada will be carried to the banks of the Rio Negro; boats will descend from the sources of the Napo and the Ucayali, from the Andes of Quito and upper Peru, to the mouths of the Oronoco—a distance which equals that from Timbuctoo to Marseilles. A country nine or ten times larger than Spain, and enriched with the most varied productions, is navigable in every direction by the medium of the natural canal of the Cassiquiari and the bifurcation of the rivers. This phenomenon, which one day will be so important for the political connexions of nations, unquestionably deserves to be carefully examined."

If these things should, in the estimation of Humboldt, "fix the attention of commercial Europe," much more should they occupy ours. A glance at the map, and a reflection upon the course of the trade-winds, will show conclusively that no ships can sail from the mouths of the Amazon and Oronoco without passing close by our southern ports. Here, then, is the natural depot for the rich and varied productions of that vast region. Here, too, can be found all that the inhabitants of that region require for their support and comfort; and I have not the slightest doubt, if Brazil should pursue a manly policy, and throw open her great river to the trade of the world, that the United States would reap far the largest share of the benefits to be derived from it.

Whilst at Barra, I had conversations with a man who had made several trading voyages up the "Purus." Ever since I had read the pamphlet of Father Bobo de Revello, in which he attempts to show that a navigable river, which he saw to the eastward of Cuzco, and which he calls Madre de Dios, is identical with the Purus, this river has had for me a great interest. I sent Mr. Gibbon to look for its head-waters, and I determined, if possible, to ascend it from its mouth. I am not aware of the reasons which induced Gibbon to abandon the search for its sources, though I suspect they arose from the well-known fierce and hostile character of the savages who dwell on its upper banks. But, for myself, I am compelled to acknowledge that when I arrived at Barra, near the mouth of the Purus, I was broken down, and felt convinced that I could not stand the hardship and exposure necessary for a thorough examination of this river.

According to the statements of my informant—a very dark Brazilian, named Seraphim—the Purus commences to rise in October, and to fall in May. The best time to ascend it is when the river is quite full and done rising—in May. The beaches are then covered, and slack water is found close in to the proper shores of the river.

Fifteen days, or about two hundred and fifty miles from the mouth, is the mouth of a stream called Parana-pishuna, which, by a succession of lakes and a portage of a day, connects the Purus with the Madeira. The connexion is only passable when the river is full. About the mouth of this stream, the sezoens, or intermittent fevers, are said to be very fatal; but a few days of navigation takes the voyager above their locality and out of their influence. There are several large lakes between the mouth of the Purus and that of the Parana-pishuna.

Thirty days from the mouth of the Purus is the mouth of a river called the Mucuin, which also communicates with the Madeira, above the rapids of that river. The banks of the Mucuin are low and level; the river is shallow, and the rocks make the passage up and down tedious and laborious in the dry season, which is from May to October. The ascent of the Mucuin takes thirty-five days to arrive at the "Furo," which connects it with the Madeira; and the navigation of the Furo takes ten more. I did not understand from Senhor Seraphim that there were any whites on the banks of the Mucuin; but he told me there were broad-tailed sheep there—such as are called in Brazil sheep of five quarters, on account of the weight and value of the tail. If this be true, I suspect that the Mucuin runs through a portion of the great department of Beni, belonging to Bolivia; that it communicates with the Madeira by means of the river Beni; and that these sheep have either been stolen by the Indians, or have strayed from whites who live about the little town of Cavanas, situated on a tributary of the Beni.