The reporter was clinging unsteadily to his friend's shoulder. Sprague suddenly realized that Sturgis in his turn was succumbing to the effects of the gas. He sprang back in time to catch the staggering man in his arms. "Selfish brute that I am!" he exclaimed. "Here; it is your turn to breathe!" And he pushed the reporter toward the tube. "No, no," said Sturgis, struggling faintly; "it cannot be both----and you----have----everything----to live for." But the artist was now the stronger, and he succeeded in forcing his friend to inhale enough fresh air to restore his departing consciousness. At length Sturgis, with returning strength, was about to renew the generous struggle with Sprague, when suddenly the place was ablaze with the glare of an electric light. "He wants to see if his work is done," whispered Sturgis to his companion. Then, observing that Sprague was again on the verge of asphyxiation, he continued hurriedly: "Fill your lungs with air, quick!----quick, I tell you. Now drop and feign death. Do as I do." Suiting the action to the word, Sturgis threw himself upon the stone floor, face downward, and lay motionless, his right hand grasping a revolver concealed beneath his body. Sprague, after a short breathing spell at the tube, followed his companion's example. After a short interval there came a metallic click, which Sturgis recognized as the sound made by the opening of the slide in the panel of the door at the head of the stairs. A moment--which seemed an eternity of suspense--followed, during which the prisoners felt, without being able to see, the cold gleam of the steely eyes of Murdock at the grating. Would he enter? Would he suspect the ruse? Would the two men retain their grasp of consciousness and their strength long enough to make a last fight for life? These thoughts crowded upon the reporter's brain as he lay simulating death and making a desperate effort to control his reeling senses. If Murdock were coming he would have to shut off the gas and to ventilate the room. What was he waiting for? "Come in!" The words were Murdock's as he turned away from the grating and closed the sliding panel. "An interruption which probably means death to us," whispered Sturgis to his companion; "take another breath of fresh air, old fellow; we must hold out a little longer." Sprague, however, lay motionless and unresponsive. The reporter shook him violently and turned him over upon his back. The artist's body was limp and inert; his eyes half closed; his face livid. The reporter himself felt sick and faint. But, with a mighty effort, he succeeded in raising his friend in his arms, and dragging him toward the speaking-tube. There, of a sudden, his strength failed him. His head swam; his muscles relaxed; he felt Sprague's limp form slip from his grasp, tottered, reeled, threw his arms wildly about him for support, and fell, as the last elusive ray of consciousness was slipping away from him.