Cheered by this event, Zeballos lost no time in pursuing his success, and marched with a thousand men against Fort _Sta. Teresa_, which place capitulated; whereupon the Spanish general pushed forward his troops to _Rio Grande_, the short passage by which the waters of the _Lagoa dos Patos_--the largest lake in _Brazil_--discharge themselves into the sea. It may be of interest to observe that the great lake in question, which is one hundred and eighty miles in length, owes its name of “lake of ducks” to the fact of some Spanish vessels being driven into the _Rio Grande_ by stress of weather in 1554, and leaving there some ducks, which spread in enormous numbers. Zeballos directed his arms against the town of _S. Pedro_, the inhabitants and garrison of which place fled with precipitation. [Sidenote: 1763.] When the news of these proceedings reached Portugal, the far-seeing Pombal became alarmed for the safety of _Minas Geraes_. As his imagination was filled, day and night, with the thought of the Jesuits, he conjured up the notion that by their aid the enterprising Zeballos might obtain a powerful army from the “Reductions.” Had time permitted, there is no doubt that such a force would have been brought into the field. Indeed the Jesuits on the _Moxo_ frontier were now in arms, and the Spaniards and Portuguese were in conflict in the very centre of the continent. As, however, the operations which they undertook resulted in the _status quo ante_ being reverted to by the Peace of Paris, it is unnecessary to recount them in detail. By this treaty, however, the question of demarcation was left in the same condition. Zeballos was required to restore _Colonia_, but he did not think it necessary to give up _Rio Grande_.