To the eastward of the river Salado lies the vast region commonly called the Gran-chaco, or desert, which extends to the Paranã, and reaches north as far as the province of Chiquitos, solely inhabited by Indians of various tribes, who, safe in their own forests and jungles, have there found a refuge from Spanish domination and persecution. It is through this territory that the rivers Pilcomayo and Vermejo wind their tortuous courses to the Paranã from the most remote parts of the interior of the Upper Provinces. Some way beyond the Salado, about seventy leagues east from Santiago (in lat 27° 28´), was found that very remarkable specimen of native iron which I sent to this country some years ago, and which is now deposited in the British Museum. Its existence was first made known by some of the people of Santiago, who had passed through that part of the country in their journeys to the forests beyond to collect honey; and their reports, which were transmitted to Buenos Ayres, induced the Viceroy, in 1788, to send Don Reuben de Celis, an officer in the King's service, to examine it. His report upon it was published in the Philosophical Transactions of the Royal Society of London for 1788, and excited much speculation at the time. As in those times the working of iron was forbidden in South America, after sundry specimens of it were forwarded to Lima, to Buenos Ayres, and to Spain, the remainder lay neglected for many years in its original site. In the beginning of the struggle for independence, however, when the Spanish ships of war blockaded Buenos Ayres, iron, amongst other necessaries, becoming extremely scarce, the people recollected De Celis's account, with the reports of the Indians, that in the same parts there were extensive veins of the same mineral; and at a great expense the mass in question was sent for and brought to Buenos Ayres. By the time it got there the blockade was over; and as it was evidently much easier to procure iron from Europe than by a cart-carriage of 1000 miles from the uninhabited wilds of the Chaco, no further trouble was taken to determine whether or not the Indian reports of its being procurable in larger quantities were true or not. By way of experiment a pair of pistols were manufactured from it, which were sent as a present to the President of the United States, and what remained was placed at my disposal by the Minister of Buenos Ayres on the occasion of my signing the treaty with him in 1825, which recognised on the part of Great Britain the political independence of his country. I sent it to Sir Humphrey Davy to be placed in the British Museum, hoping that he would himself have analysed it, and given his opinion respecting its supposed meteoric origin. The analysis I believe was never made, owing to his death, which occurred very shortly after the arrival of the iron in this country.