On the 18th of April this hill, several hundred feet in rugged height, was assailed in front and rear, the Americans gallantly climbing the steep rocks in the face of a deadly fire, carrying one barricade after another, and at length sweeping over the ramparts of the summit fortress and driving the defenders from their stronghold down the mountain-side. Santa Anna took with him only eight thousand men in his hasty retreat, leaving three thousand as prisoners in the American hands, with forty-three pieces of bronze artillery and a large quantity of ammunition. Within a month afterwards Scott’s army marched into the city of Puebla, on the table-land, sixty-eight miles from the capital. Here they rested for several months, awaiting reinforcements. On August 7 the army resumed its march, now less than eleven thousand strong, the term of several regiments having expired and their places been partly filled by untried men, none of whom had ever fired a gun in war. On they went, up-hill still, passing the remains of the old city of Cholula with its ruined Aztec pyramid, and toiling through a mountain region till Rio Frio was reached, fifty miles from Puebla and more than ten thousand feet above the level of the sea. A few miles farther and the beautiful valley of Mexico lay suddenly revealed before them like a vision of enchantment. It was a scene of verdant charm, the bright green of the fields and groves diversified with the white walls of villages and farm-houses, the silvery flow of streams, and the gleaming surface of winding lakes, while beyond and around a wall of wooded mountains ascended to snowy peaks. It was a scene of summer charm that had not been gazed upon by an invading army since the days when Cortez and his men looked down upon it with warm delight. The principal lakes visible were Lake Chalco, with the long, narrow lake of Xochimilco near it, and seven miles to the north Lake Tezcuco, near the western shore of which the city of Mexico was visible. Between Chalco and Tezcuco ran the national road, for much of its length a narrow causeway between borders of marsh-land. Near Lake Xochimilco was visible the Acapulco road. Strong works of defence commanded both these highways. [Illustration: ON THE BORDER OF LAKE CHALCO.] ON THE BORDER OF LAKE CHALCO.