[Footnote 18: This obtaining of _sebo humano_, or "human tallow," by the Spaniards seems to have been practised in Peru also, according to stories told me by the natives of the Andes, and recorded in my book, "The Andes and the Amazon."] Plans were then laid for an attack upon the island-city. But before this it was necessary to subjugate some troublesome Indians to the west, and the expedition to Cuernavaca was successfully carried out. A remarkable incident of this was the surprise attack upon the enemy in an impregnable position, by the crossing of a profound chasm by means of two overhanging trees, which were utilised as a natural bridge by some Tlascalans and the Spaniards, who passed the dangerous spot by this method. Return was then made to Xochimilco on the fresh-water lake of that name, adjoining at that time that of Texcoco on the south. The name of this place in the Aztec tongue signifies "The Field of Flowers," for there were numbers of the singular _chinampas_, or floating-gardens, which were a feature of the aquatic life of the Mexicans, existing upon this lake. The siege operations were conducted vigorously both by land and water. Again before the eyes of the Spaniards stretched that fatal causeway--path of death amid the salt waters of Texcoco for so many of their brave comrades upon the _Noche Triste_ of their terrible flight from Tenochtitlan. And there loomed once more that dreaded _teocalli_, whence the war-drum's mournful notes were heard. Guarded now by the capable and persistent Guatemoc, the city refused an offer of treaty, and invited the destruction which was to fall upon it. From the _azoteas_, or roofs of their buildings and temples, the undaunted Mexicans beheld the white-winged brigantines, armed with those belching engines of thunder and death whose sting they well knew: and saw the ruthless hand of devastation laying waste their fair town of the lake shore, and cutting off their means of life.