He spoke very quietly and reassuringly, as if being shut up in a fallen tunnel between two masses of earth were a matter that needn't cause one the slightest uneasiness; but his words suggested to Elma's mind a fresh and hitherto unthought-of danger. "Eighteen hours," she cried, horror-struck. "Do you mean to say we may have to stop here, all alone, for eighteen hours together? Oh, how very dreadful! How long! How frightening! And if they don't dig us out before eighteen hours are over, do you mean to say we shall die of choking?" Cyril gazed down at her with a very regretful and sympathetic face. "I didn't mean to frighten you," he said; "at least, not more than you're frightened already; but, of course, there's only a certain amount of oxygen in the space that's left us; and as we're using it up at every breath, it'll naturally hold out for a limited time only. It can't be much more than eighteen hours. Still, I don't doubt they'll begin digging us out at once; and if they dig through fast, they may yet be in time, even so, to save us." Elma bent forward with her face in her hands again, and, rocking herself to and fro in an agony of despair, gave herself vip to a paroxysm of utter misery. This was too, too terrible. To think of eighteen hours in that gloom and suspense; and then to die at last, gasping hard for breath, in the poisonous air of that pestilential tunnel. For nearly an hour she sat there, broken down and speechless; while Cyril Waring, taking a seat in silence by her side, tried at first with mute sympathy to comfort and console her. Then he turned to examine the roof, and the block at either end, to see if perchance any hope remained of opening by main force an exit anywhere. He even began by removing a little of the sand at the side of the line with a piece of shattered board from the broken carriage in front; but that was clearly no use. More sand tumbled in as fast as he removed it. He saw there was nothing left for it but patience or despair. And of the two, his own temperament dictated rather patience. He returned at last, wearied out, to Elma's side. Elma, still sitting disconsolate on the footboard, rocking herself up and down, and moaning low and piteously, looked up as he came with a mute glance of inquiry. She was very pretty. That struck him even now. It made his heart bleed to think she should be so cowed and terrified. "I'm sorry to bother you," he said, after a pause, half afraid to speak, "but there are four lamps all burning hard in these four compartments, and using up the air we may need by-and-by for our own breathing. If I were to climb to the top of the carriage--which I can easily do--I could put them all out, and economize our oxygen. It would leave us in the dark, but it'd give us one more chance of life. Don't you think I'd better get up and turn them off, or squash them?" Elma clasped her hands in horror at the bare suggestion.