San Martin had remained only a few days in Santiago, hurrying back to Buenos Aires to try to induce the Argentine government to carry out its promises of the year before and aid in the purchase of a fleet. Just before his departure an East Indiaman, carrying forty-four guns, had arrived at Valparaiso and the Chilean treasury was emptied to pay for her. When he reached Buenos Aires his friend Puerreyedon, the Argentine dictator, agreed to raise a loan of five hundred thousand dollars and send around two ships of the Argentine navy. San Martin immediately took the road for Chile, but at Mendoza a letter came forbidding him to draw on the Argentine treasury. He resigned, but the Argentine authorities, dismayed at the consequences of his withdrawal, finally gave him two hundred thousand dollars.
The winter storms make the Andean passes impracticable, and it was October before the general reached Santiago, where to his delight he found that O'Higgins had already got together a considerable squadron. The East Indiaman, bought just before Maipo, and manned by British and North American officers, had succeeded in capturing a Spanish brig. Two American privateers were shortly afterwards bought by the Chilean government, and their arrival was followed by that of an English vessel purchased by San Martin's agent in London. Others were on their way from the United States and two Argentine ships were reported to be coming around Cape Horn. A few days prior to San Martin's return to Santiago, Chile's two frigates with two smaller consorts had sailed south from Valparaiso in the hope of intercepting a fleet of transports, carrying two thousand troops and a great quantity of arms, which the Spanish government had sent around the Horn from Cadiz convoyed by a fifty-gun frigate. Stormy weather had, however, scattered the royalist fleet and more than half the transports gave up the attempt to weather the formidable promontory, though the frigate and the others succeeded. The transports evaded the Chileans and reached Callao in safety, but the frigate was caught lying at anchor in Talcahuano, and proved an important addition to the patriot navy.
The object for which San Martin had been planning and working during two years was achieved. His naval force, manned by professional sailors picked from among the best sea-fighting people of the world, was too formidable for the enemy to dare to attack. Chile was safe from invasion and Peru lay open to a descent. San Martin's first care was to wrest southern Chile from the Spaniards. To leave them in control of a fertile and populous territory where they could recruit troops, collect provisions, and menace Santiago was not safe. Toward the end of 1818 he sent his lieutenant, Balcarce, an Argentine, against them at the head of thirty-five hundred men. Such a force was irresistible; Chillan, Concepcion, and Talcahuano were abandoned and the Spanish commander shut himself up in the fortress of Valdivia.