Before daybreak the engineer was up again, and active. Now that he faced the light of morning, with a thousand difficult problems closing in on every hand, he put aside his softer moods, his visions and desires, and--like the scientific man he was--addressed himself to the urgent matters in hand. "The girl's safe enough alone, here, for a while," thought he, looking in upon her where she lay, calm as a child, folded within the clinging masses of the tiger-skin. "I must be out and away for two or three hours, at the very least. I hope she'll sleep till I get back. If not--what then?" He thought a moment; then, coming over to the charred remnants of last night's fire, chose a bit of burnt wood. With this he scrawled in large, rough letters on a fairly smooth stretch of the wall: "Back soon. All O. K. Don't worry." Then, turning, he set out on the long, painful descent again to the earth-level. Garish now, and doubly terrible, since seen with more than double clearness by the graying dawn, the world-ruin seemed to him. Strong of body and of nerve as he was, he could not help but shudder at the numberless traces of sudden and pitiless death which met his gaze. Everywhere lay those dust-heaps, with here or there a tooth, a ring, a bit of jewelry showing--everywhere he saw them, all the way down the stairs, in every room and office he peered into, and in the time-ravished confusion of the arcade. But this was scarcely the time for reflections of any sort. Life called, and labor, and duty; not mourning for the dead world, nor even wonder or pity at the tragedy which had so mysteriously--befallen. And as the man made his way over and through the universal wreckage, he took counsel with himself. "First of all, water!" thought he. "We can't depend on the bottled supply. Of course, there's the Hudson; but it's brackish, if not downright salt. I've got to find some fresh and pure supply, close at hand. That's the prime necessity of life. "What with the canned stuff, and such game as I can kill, there's bound to be food enough for a while. But a good water-supply we must have, and at once!" Yet, prudent rather for the sake of Beatrice than for his own, he decided that he ought not to issue out, unarmed, into this new and savage world, of which he had as yet no very definite knowledge. And for a while he searched hoping to find some weapon or other. "I've got to have an ax, first of all," said he. "That's mans first need, in any wilderness. Where shall I find one?" He thought a moment. "Ah! In the basements!" exclaimed he. "Maybe I can locate an engine-room, a store-room, or something of that sort. There's sure to be tools in a place like that." And, laying off the bear-skin, he prepared to explore the regions under the ground-level. He used more than half an hour, through devious ways and hard labor, to make his way to the desired spot. The ancient stair-way, leading down, he could not find.