The population has greatly diminished;--perhaps in the whole province there are not now more than 15,000 or 20,000 souls, a large proportion of which is of Guarani origin, the descendants of emigrants from the Jesuit missions in Paraguay, who abandoned them after the expulsion of their pastors in 1768. This state of things is the more lamentable as Santa Fé might, under a different system, become one of the most important points of the Republic: once more under the decided protection of the Government of Buenos Ayres, not only might its own particular interests be vastly advanced, but the greatest benefits might result to the rest of the union. Its situation offers striking facilities for carrying on a more active transit-trade between Buenos Ayres and the provinces north of Cordova. The river Salado, on which it stands, is known to be navigable for barges as high up as Matara, in the province of Santiago, and at no great distance from that city; if it were made use of there would be a saving of upwards of 250 leagues of land-carriage in conveying goods from Buenos Ayres to Santiago; but, even if this should turn out not to be so practicable as it is said to be, a direct road is open from Santa Fé which, passing by the lakes of Porongos, skirts the river Dulce, and falls into the high road from Cordova a few posts south of the city of Santiago; which, at the lowest computation, would still be 100 leagues short of the over-land route now used from the capital to the Upper Provinces by way of Cordova. In any part of the world such a saving of land-carriage would be a considerable object; but in a country where the roads are just as nature has made them, and where the only means of transport for heavy goods are the most unwieldy of primitive waggons, drawn by oxen--the slowest of all conveyances,--not to speak of its expense, and the risks, independently of the wear and tear necessarily attending it, it becomes of the greatest importance. That it has not hitherto been available, is owing to the difficulties attending the navigation of a large river, not only against the current, but against a prevalence of contrary winds, which have rendered the passage of the Paranã up to Santa Fé even more tedious and expensive than the long over-land journey. But the introduction of steam-boats would at once obviate this, and enable the people of Buenos Ayres to send their heaviest goods to Santa Fé by water-carriage in less time than a horse can now gallop over the intervening country, for there is no reason in the world why the ordinary voyage thither should exceed at the utmost three days. I can hardly imagine a greater change in the prospects of a people than this would open to the Santa Fecinos.