'The unknown made no reply. I therefore stepped back and drew out my revolver. Dialogues carried on by knives and fire-arms are by no means of rare occurrence at mid-night in the streets of Mexico; but I was anxious, ere proceeding to extremities, to have a good look at my antagonist. Although the Cathedral Square was illumined by a magnificent moonlight, still I could not succeed. His hat was forced down over his brow; his ample cloak was raised, and the folds covered the lower portion of his face entirely. I could distinguish only a pair of glaring eyes, and also discover that his long hair, which nearly reached his shoulders, was almost perfectly white. 'The contemptuous silence and disdainful listlessness of my cloaked adversary tended rather to enrage than calm me; so, with my revolver in full view, and my arm stretched forth, I advanced toward him. ''I have already once demanded who you are, and you have not seen fit to answer me. As I intend entering this house, and can not do so in safety, since you block my passage, and may have a dagger hidden beneath your cloak, I warn you, unless you clear the way, I shall be obliged to proceed to violent means to enforce my demand.' 'Whether the unknown was duly impressed with wholesome prudence, by the tone of my voice and the sight of my pistol; whether, finding he had woke up the wrong customer, he determined to change his tactics; or whether he had no sinister motives, I could not then determine; suffice it to say, he evacuated the disputed territory, and with a measured and majestic step, moved away some eight or ten paces, reminding me of a stage bandit, in some Bowery melodrama. 'Keeping my face toward him, and letting no movement of his body escape me, I knocked loudly at the door, and in a minute more Donna Lopez herself opened it, and I entered. 'Mexican houses all are provided with two doors, and my hostess and I had not crossed the vestibule leading to the inner one, when the knocker fell on the outer door, with a force that fairly startled the obese Teresa. ''Holy Virgin!' exclaimed she, 'who can be there at this hour? But angels defend us, why, Señor, have you your pistol in your hand?' 'In a few words, I explained to her the adventure which had befallen me at the door; but ere I had fairly ended, the door shook with the increased violence with which the knocker now fell upon it. I rushed forward to open it. ''For mercy's sake, Señor, be prudent; do not open it,' said my terrified hostess, 'wait--wait, I will go myself.' 'Poor Donna Teresa, overpowered by fear, was slower than even was her custom, in obeying the impetuous summons, and as she reached the door, it shook for the third time beneath the rapid blows of the knocker. 'Who is there?' said she, in a faltering tone, opening a little slide which was so protected by bars and cross-bars as to prevent the intrusion of a dagger or even the muzzle of a pistol; 'who is there?'