"I can endure this no longer," I said. "I must see who it is that makes that music. It is the product of a human heart and must come from the touch of human fingers." We carefully shifted our position until we stood in the blaze of light that poured out of the door. The doorway was an immense arched opening, magnificently ornamented, rising to a height of, I should say, not less than twenty or twenty-five feet and broad in proportion. The door itself stood widely open and it, together with all of its fittings and surroundings, was composed of the same beautiful red metal. A Beautiful Girl! Stepping out a little way into the light I could see within the door an immense apartment, glittering on all sides with metallic ornaments and gems and lighted from the centre by a great chandelier of electric candles. In the middle of the great floor, holding the instrument delicately poised, and still awaking its ravishing voice, stood a figure, the sight of which almost stopped my breath. It was a slender sylph of a girl! A girl of my own race: a human being here upon the planet Mars! Her hair was loosely coiled and she was attired in graceful white drapery. "By ----!" cried Colonel Smith, "she's human!" Chapter XII. Still the bewildering strains of the music came to our ears, and yet we stood there unperceived, though in the full glare of the chandelier. The girl's face was presented in profile. It was exquisite in beauty, pale, delicate with a certain pleading sadness which stirred us to the heart. An element of romance and a touch of personal interest such as we had not looked for suddenly entered into our adventure. Colonel Smith's mind still ran back to the perils of the plains. A Human Prisoner. "She is a prisoner," he said, "and by the Seven Devils of Dona Ana we'll not leave her here. But where are the hellhounds themselves?" Our attention had been so absorbed by the sight of the girl that we had scarcely thought of looking to see if there was any one else in the room. Glancing beyond her, I now perceived sitting in richly decorated chairs three or four gigantic Martians. They were listening to the music as if charmed. The whole story told itself. This girl, if not their slave, was at any rate under their control, and she was furnishing entertainment for them by her musical skill. The fact that they could find pleasure in music so beautiful was, perhaps, an indication that they were not really as savage as they seemed. Yet our hearts went out to the girl, and were turned against them with an uncontrollable hatred. They were of the same remorseless race with those who so lately had lain waste our fair earth and who would have completed its destruction had not Providence interfered in our behalf. Singularly enough, although we stood full in the light, they had not yet seen us. Martians Guarding Her.