"Oh dear, no!" she cried hastily. "Please, PLEASE don't do that. It's bad enough to choke slowly, like this, in the gloom. But to die in the dark--that would be ten times more terrible. Why, it's a perfect Black Hole of Calcutta, even now. If you were to turn out the lights I could never stand it." Cyril gave a respectful little nod of assent. "Very well," he answered, as calm as ever. "That's just as you will. I only meant to suggest it to you. My one wish is to do the best I can for you. Perhaps"--and he hesitated--"perhaps I'd better let it go on for an hour or two more, and then, whenever the air begins to get very oppressive--I mean when one begins to feel it's really failing us--one person, you know, could live on so much longer than two... it would be a pity not to let you stand every chance. Perhaps I might---" Elma gazed at him aghast in the utmost horror. She knew what he meant at once. She didn't even need that he should finish his sentence. "Never!" she said, firmly clenching her small hand hard. "It's so wrong of you to think of it, even. I could never permit it. It's your duty to keep yourself alive at all hazards as long as ever you can. You should remember your mother, your sisters, your family." "Why, that's just it," Cyril answered, a little crestfallen, and feeling he had done quite a wicked thing in venturing to suggest that his companion should have every chance for her own life. "I've got no mother, you see, no sisters, no family. Nobody on earth would ever be one penny the worse if _I_ were to die, except my twin brother; he's the only relation I ever had in my life; and even HE, I dare say, would very soon get over it. Whereas YOU"--he paused and glanced at her compassionately--"there are probably many to whom the loss would be a very serious one. If I could do anything to save you---" He broke off suddenly, for Elma looked up at him once more with a little burst of despair. "If you talk like that," she cried, with a familiarity that comes of association in a very great danger, "I don't know what I shall do; I don't know what I shall say to you. Why, I couldn't bear to be left alone here to die by myself. If only for MY sake, now we're boxed up here together, I think you ought to wait and do the best you can for yourself." "Very well," Cyril answered once more, in a most obedient tone. "If you wish me to live to keep you company in the tunnel, I'll live while I may. You have only to say what you wish. I'm here to wait upon you." In any other circumstances, such a phrase would have been a mere piece of conversational politeness. At that critical moment, Elma knew it for just what it was--a simple expression of his real feeling. CHAPTER III. CYRIL WARING'S BROTHER.