Whether in the plain country between the Mississippi and Allegany mountains, easterly or westerly winds prevail at present, I am not informed.  I conjecture, however, that they must be westerly:  and I think with you, Sir, that if those mountains were to subside into plain country, as their opposition to the westerly winds would then be removed, they would repress more powerfully those from the east, and of course would remove the line of equilibrium nearer to the sea coast for the present.

Having had occasion to mention the course of the tropical winds from east to west, I will add some observations connected with them.  They are known to occasion a strong current in the ocean, in the same direction.  This current breaks on that wedge of land of which Saint Roque is the point; the southern column of it probably turning off and washing the coast of Brazil.  I say probably, because I have never heard the fact, and conjecture it from reason only.  The northern column, having its western motion diverted towards the north, and reinforced by the currents of the great rivers Orinoko, Amazons, and Tocantin, has probably been the agent which formed the Gulf of Mexico, cutting the American continent nearly in two, in that part.  It re-issues into the ocean at the northern end of the Gulf, and passes by the name of the Gulf Stream, all along the coast of the United States, to its northern extremity.  There it turns off eastwardly, having formed by its eddy, at this turn, the Banks of Newfoundland.  Through the whole of its course, from the Gulf to the Banks, it retains a very sensible warmth.  The Spaniards are, at this time, desirous of trading to their Philippine Islands, by the way of the Cape of Good Hope:  but opposed in it by the Dutch, under authority of the treaty of Munster, they are examining the practicability of a common passage through the Straits of Magellan, or round Cape Horn.  Were they to make an opening through the Isthmus of Panama, a work much less difficult than some even of the inferior canals of France, however small this opening should be in the beginning, the tropical current entering it with all its force, would soon widen it sufficiently for its own passage, and thus complete in a short time, that work which otherwise will still employ it for ages.  Less country, too, would be destroyed by it in this way.  These consequences would follow. 1.  Vessels from Europe or the western coast of Africa, by entering the tropics, would have a steady wind and tide to carry them through the Atlantic, through America and the Pacific ocean, to every part of the Asiatic coast, and of the eastern coast of Africa:  thus performing with speed and safety the tour of the whole globe, to within about twenty-four degrees of longitude, or one fifteenth part of its circumference; the African continent, under the line, occupying about that space. 2.  The Gulf of Mexico, now the most dangerous navigation in the world on account of its currents and moveable sands, would become stagnant