"Again, some poisonous gas may have developed, either from a fissure in the earth's crust, or otherwise. Other hypotheses are possible, but of what practical value are they now? "We only know that here, in this uppermost office of the Tower, you and I have somehow escaped with only a long period of completely suspended animation. How long? God alone knows! That's a query I can't even guess the answer to as yet." "Well, to judge by all the changes," Beatrice suggested thoughtfully, "it can't have been less than a hundred years. Great Heavens!" and she burst into a little satiric laugh. "Am _I_ a hundred and twenty-four years old? Think of that!" "You underestimate," Stern answered. "But no matter about the time question for the present; we can't solve it now. "Neither can we solve the other problem about Europe and Asia and all the rest of the world. Whether London, Paris, Berlin, Rome, and every other city, every other land, all have shared this fate, we simply don't know. "All we _can_ have is a feeling of strong probability that life, human life I mean, is everywhere extinct--save right here in this room! "Otherwise, don't you see, men would have made their way back here again, back to New York, where all these incalculable treasures seem to have perished, and--" He broke short off. Again, far off, they heard a faint re-echoing roar. For a moment they both sat speechless. What could it be? Some distant wall toppling down? A hungry beast scenting its prey? They could not tell. But Stern smiled. "I guess," said he, "guns will be about the first thing I'll look for, after food. There ought to be good hunting down in the jungles of Fifth Avenue and Broadway! "You shoot, of course? No? Well, I'll soon teach you. Lots of things both of us have got to learn now. No end of them!" He rose from his place on the floor, went over to the window and stood for a minute peering out into the gloom. Then suddenly he turned. "What's the matter with me, anyhow?" he exclaimed with irritation. "What right have I to be staying here, theorizing, when there's work to do? I ought to be busy this very minute! "In some way or other I've got to find food, clothing, tools, arms--a thousand things. And above all, water! And here I've been speculating about the past, fool that I am!" "You--you aren't going to leave me--not to-night?" faltered the girl. Stern seemed not to have heard her, so strong the imperative of action lay upon him now. He began to pace the floor, sliding and stumbling through the rubbish, a singular figure in his tatters and with his patriarchal hair and beard, a figure dimly seen by the faint light that still gloomed through the window: "In all that wreckage down below," said he, as though half to himself, "in all that vast congeries of ruin which once was called New York, surely enough must still remain intact for our small needs. Enough till we can reach the land, the country, and raise food of our own!"