The missionary Falkner had supposed that a hostile naval power might, by ascending the _Rio Negro_, surprise the Spanish territories in the interior and even in _Chili_. In order to determine this important point, and to survey the river and its affluents, an expedition was despatched from the _Rio Negro_. Starting from the settlement of _Carmen_ in 1782, it was absent for eight months. It proved the possibility of ascending the river to the foot of the _Andes_. One surprising fact was brought to light, namely, that the Indians of the _Pampas_ had not to drive their stolen cattle for more than three days’ journey over the _Cordillera_, from the lake of the boundary mentioned by Falkner, before reaching the fort of _Valdivia_, where they found a ready market. The party of Indians from whom the explorers learned this circumstance consisted of about three hundred people, who had left their country more than a year before for the purpose of collecting cattle for the Valdivians. They were now on their way homewards with about eight hundred head, each one of which bore the _Buenos Ayres_ mark. Their return voyage down the stream was accomplished in three weeks. In a work of this description I find considerable difficulty in giving due regard to the unities of time, &c. My object is to place before the reader, as well as I can, the general condition of South America at any one period; but the progress of events on that continent during the colonial administration was so irregular that it is scarcely possible to avoid appearing to give undue prominence to one particular region at a time, overlooking others which in these days may seem of equal or even greater importance. Thus whilst the province of _Buenos Ayres_ was still a vast plain overrun by savages, _Peru_, subsequent to the Spanish invasion, had a long and interesting history. In deferring to so late a date in this volume any account of _Buenos Ayres_, which is to-day a place of the first importance in South America, I may seem to be wanting in a sense of comparative fitness. But on reflection the reader will perceive that for the first two hundred years of its existence _Buenos Ayres_ possessed no history beyond that of its foundation. Its records during those years, in so far as the world in general is interested, may be comprised in a single sentence. It was on the collapse of the narrow, repressive policy of Spain, and the erection of _Buenos Ayres_ into a Viceroyalty, that the history of that city and province may be said to commence. Notwithstanding its natural resources and its geographical importance, it was until that date, like _Tucuman_, merely the seat of a local government, one amongst several, dependent on the Viceroyalty of _Peru_. In the last quarter of a century, however, of its colonial existence it made colossal strides. The new prospects of commercial wealth absorbed the interests and thoughts of all; and whilst Europe was