But here was an escape from such disagreeable conditions. Here was an unused room! Why should it not become a refuge from the noise, the dirt, and the turmoil of the factory? The plan seemed innocent enough, and when Peter confided it to Nat neither of them could see the slightest objection to it. In consequence, at noon time they crept up-stairs, and arranged a cozy little corner for themselves behind the packing-cases. It was almost as good as playing Robinson Crusoe, this building a fortress and hiding inside it. Then, too, the constant chance of being discovered provided just the necessary tremor of excitement to make it interesting. What fun it was! They called their stronghold Sterling Castle, and many a joke and jibe they made concerning it--jokes at which they laughed heartily when they were by themselves. The vast empty space, they learned by cautious questioning, had originally been intended as a supply room; it was found, however, that it was not needed for this purpose and therefore it had been left in its present unoccupied condition. There seemed not an iota of possibility that the place would ever be used and Peter and Nat exulted in the fact that they might lunch there undisturbed for the rest of their days if they so desired. For weeks they spent every noon hour in the sunshine behind their barricade talking softly together, eating their luncheon, and sometimes reading aloud. Then came calamity. It was on a sharp April day when the shelter of their sunny corner was especially welcome. Peter had just been rolling out one of the most stirring chapters of "Ivanhoe" when suddenly he paused, listening intently. "It's the elevator!" he whispered. "It is stopping at this floor. Somebody is getting out, Nat." "Who can it be?" "Hush!" The two boys kept very still. Steps and voices came nearer. "Yes, every floor is protected by fire-escapes, as you see," declared a voice. "It is some insurance man," breathed Peter. "Don't move, Nat." "Have you hand extinguishers here also?" "Yes, at each corner of the room and on the walls." "This floor is not in use, I take it." "No," broke in another voice--the voice of Mr. Coddington himself. "We never have had occasion to use this floor, although we probably shall do so when we require more room for supplies. What are those packing-cases doing here, Tyler? They look as though they were empty." "I hardly think empty cases would be left on this floor, sir. They shouldn't be." Mr. Tyler was evidently annoyed. "Empty or full, they've no business in this room," said Mr. Coddington, sharply. "They might cause fire." Simultaneously the three men stepped forward to investigate. Mr. Tyler kicked the back of the nearest case with his foot, but Mr. Coddington, who never stopped until he had got at the bottom of things, grasped the edge of one of the great boxes and tried to turn it over. Now it happened that the boys, struggling to remain unseen, had huddled into this very box.