The spluttering candle gave its last flicker and went out, leaving the prisoners in utter darkness. The room was rapidly filling with gas, and they were beginning to feel its effects. "We can at least complete our task before we die," said Sturgis with grim determination. "Our task!" "Yes, and insure Murdock's conviction for our murder." "What chance is there that any one will ever discover our bodies, since they are destined for Murdock's oblivion tank?" "Give me your hand," Sturgis replied; "there is a box of matches. I place it here, between us, within easy reach. I want to write a few words to the superintendent of police to explain matters. By that time there will be enough gas in the room to produce a terrific explosion, when we strike a match. We can thus succeed in wrecking this place and calling attention to it. If I should succumb before you do, do not fail to light the match." While he was speaking, the reporter had taken from his pocket a pad and a pencil, and had begun to write as rapidly as he could in the darkness. Sprague's head was beginning to swim and his ears were ringing, but the thought of Agnes Murdock was uppermost in his mind. "An explosion!" he exclaimed; "no, no; that must not be. What of Agnes? She may be hurt?" Sturgis continued writing. "It is the only chance there is of bringing Murdock to justice," he said, firmly. "But Agnes is innocent of his crimes," urged the artist, in a thick voice. His tongue clove to his palate; he felt his consciousness ebbing. "Why should she suffer? I am going, old man----I cannot hold out any longer----Promise me that you----that you will not----strike----the match----" He staggered and fell against the reporter, who caught him in his arms. His own senses were reeling. "Promise----" pleaded the half-unconscious man. "I promise," answered Sturgis, after an instant's hesitation. It struck a chill to his heart to see his friend dying in the prime of youth, strength and happiness. Suddenly a thought flashed upon him. "Brace up, old fellow. All is not yet over. The speaking-tube leads to fresh air. Here, put your lips to it, and breathe through your mouth." The artist heard the words and made an effort to obey these directions. With Sturgis's assistance he managed to place his lips to the mouthpiece of the speaking-tube. A few whiffs of comparatively fresh air sent the sluggish blood coursing through his veins, and gave him a new hold on life. With renewed vigor came the animal instinct to fight to the last for existence. As the shadows of death which had been closing in upon him receded, he became conscious of Sturgis's voice beating upon his ears in broken and scarcely audible tones. "It is----the last chance----Stick----to the tube----When he comes----surprise him----your revolver----shoot----before----"