Malaspina Surveys the Shores of the Rio de la Plata in 1789. Bauza maps the Road to Mendoza: De Souillac that to Cordova. Azara, and other Officers, in 1796, fix the positions of all the Forts and Towns in the Province of Buenos Ayres. Don Luis de la Cruz crosses the Pampas, from the frontiers of Conception in Chile to Buenos Ayres, in 1806. Attempt at a new delineation of the Rivers of the Pampas from his Journal. His account of the Volcanic appearances along the Eastern Andes. Sulphur, Coal, and Salt found there, also Fossil Marine Remains. The Indians of Araucanian origin: Habits and customs of the Pehuenches.
Piedra's orders confined him to the east coast of Patagonia, as has been shown in the preceding chapter; but in 1789 Spain sent forth an expedition of much more importance, especially in a scientific point of view.[27]
The ships employed were the Atrevida and Descubierta, under the command of the well-known Malaspina, who not only revised Piedra's and Viedma's surveys of Patagonia, but, rounding Cape Horn, explored the greater part of the coast of the Pacific, from its southern extreme to the Russian settlements in the north-west. Malaspina, upon his return, was thrown into a dungeon and deprived of his papers,—why, has never transpired; nor was it till several years afterwards that those admirable charts, the results of his labours, were published by order of Langara, the Spanish Minister of Marine, which have since been so useful to modern navigators in the South American Seas, and will long be an honour to the Spanish navy. Malaspina's name, however, was not permitted to be affixed to them, neither has the journal of his voyage ever been published.
It is only very recently that the details have been discovered at Buenos Ayres of the first portion of his work, viz., the survey, in 1789, of the whole of the northern and southern shores of the Plate, as high up as the Paranã, in which nearly 150 points were fixed by him. In the Appendix all those of any importance will be found, in a tabular form, together with other positions, determined on good authority.
It was this survey, with the soundings afterwards taken by Oyarvide (who lost his life in completing them), that furnished the materials for the chart of the river Plate, officially published at Madrid in 1810: nor was this all that Buenos Ayres owed to Malaspina: upon his return to Valparaiso from the north-west coast, he detached two of his most intelligent officers, Don José Espinosa, and Don Felipe Bauza, well known in this country, to map the road across the pampas; and by them the true positions of Santiago in Chile, of Mendoza, San Luis, the post of Gutierres on the river Tercero, and other points along the line, were, for the first time, determined. Their map, so far as it extends, is the best, and the only one of that line of country, I believe, ever drawn by any one capable of taking an observation.[28]
Whilst they were thus engaged in fixing one part of the geography of the interior, the Viceroy turned to account the temporary sojourn at Buenos Ayres of some of the officers attached to the commission for laying down the boundaries under the treaty of 1777 with Portugal, and employed them in mapping other portions of the territory under his immediate jurisdiction.
In 1794 M. Sourreyere de Souillac, the astronomer of the third division of that commission, laid down the line of road from Buenos Ayres to Cordova, and fixed the latitude of that city in 31° 26´ 14".
In 1796 Azara, with Cerviño and other officers employed on the same service, made a detailed survey of the frontiers of the province of Buenos Ayres, in the course of which they fixed the positions of all the towns and forts of any importance between Melinqué, its north-western extremity, and the most southern bend of the river Salado, beyond Chascomus. That river they found to have its origin in a lake in latitude 34° 4´ 45", longitude from Buenos Ayres 3° 36´ 32"; it is an insignificant stream, of trivial importance till joined by the Flores.
Thus materials were collected for laying down a considerable portion of country upon the very best authorities; but, like the surveys of the coast, many years were suffered to elapse ere they were made available to the public. Bauza's map was not published till 1810, and it was only in 1822 that the positions fixed by Azara in 1796 appeared for the first time as his in the "Statistical Register," published that year at Buenos Ayres. De Souillac's might have remained unknown for ever, had not Señor de Angelis lately brought them to light; as well as Malaspina's "Fixed Points on the Shores of the River Plate."
But, after all, however valuable were these data in perfecting a knowledge of the country already occupied, they led to no new discoveries, and by far the greater part of the interior of the continent, to the south of the Plate, remained unexplored, till Spain becoming involved in the general war carried on between the great powers in Europe, her colonial subjects on the shores of the Pacific began to experience more or less inconvenience from the stoppage of their ordinary trade. They found that the ships which used to visit them direct from Europe for the most part ran into the river Plate, rather than encounter the increased risk of capture in the longer voyage round Cape Horn; and it became therefore to them an object of considerable importance to shorten, if possible, the over-land journey from thence to the opposite side of the continent, and particularly to the southern parts of Chile.