At this place the river flows through a flat valley, which is from six hundred to eight hundred yards in width, and is bordered by lines of hills from four hundred and fifty to six hundred feet in height. The government forces numbering six thousand, three hundred and twenty-two men, were located on the southern bank of the river at Concon, where their line was about three miles in length. They were armed with old rifles, while the troops of the revolutionists were provided with Mannlicher rifles of the newest pattern. General Korner, who was in charge of the congressists, did not hesitate before this formidable position. He divided his forces into three parts. One forded the icy-cold waters of the Aconcagua at Concon _bajo_ and attacked the flank of the enemy. The second and third brigades engaged them from the opposite side of the river, and then crossed the river higher up. The ships of the navy also directed their fire against the Balmacedists. The battle was begun on the morning of the 21st. The government troops ran short of ammunition and began to give way. After four and one-half hours of fighting the battle was won. Retreat soon turned into a rout, and the defeated forces fled in every direction. The government loss was seventeen hundred killed and wounded, and fifteen hundred men and all their artillery captured. The revolutionists had only eight hundred and sixty-nine casualties. The result was a decided victory for Balmaceda’s enemies. Of the Balmacedist troops only two thousand could be mustered after this disaster. But thousands of other troops were hurried to Valparaiso before railroad communication was severed. A slight repulse was given the congressists near Viña del Mar. The army then took a wide detour in order to attack Valparaiso from the southeast. The government forces took possession of the heights at Placilla and awaited the expected battle. Each army at this time exceeded nine thousand men and were evenly balanced. But the government forces were disheartened, even though they occupied an exceptionally strong position. Their cavalry seems also to have been untrustworthy, for they gave no intelligence of this expected move of the enemy. No less than four hundred cavalrymen actually deserted and joined the other army. The country through which the congressists marched was broken, full of small streams and marshes. Hundreds of weary stragglers slept out under the trees. They reached Las Cadenas on the 27th and rested during that night. Early on the morning of the following day they started for the Balmacedist position on the heights, and this seems to have been the first knowledge that army had of the presence of the foe. The revolutionists began the engagement with artillery fire. The advance was stubbornly resisted, but a bayonet charge carried an outpost. A hand-to-hand conflict ensued until the defenders finally threw down their arms. Generals Alcerrica and Barbosa fought valiantly until killed.