He was pretty sure that the latter plan of the goblins was to inundate the mine by breaking outlets for the water accumulated in the natural reservoirs of the mountain, as well as running through portions of it. While the part hollowed by the miners remained shut off from that inhabited by the goblins, they had had no opportunity of injuring them thus; but now that a passage was broken through, and the goblins' part proved the higher in the mountain, it was clear to Curdie that the mine could be destroyed in an hour. Water was always the chief danger to which the miners were exposed. They met with a little choke-damp sometimes, but never with the explosive firedamp so common in coal-mines. Hence they were careful as soon as they saw any appearance of water. As the result of his reflections while the goblins were busy in their old home, it seemed to Curdie that it would be best to build up the whole of this gang, filling it with stone, and clay or lie, so that there should be no smallest channel for the water to get into. There was not, however, any immediate danger, for the execution of the goblins' plan was contingent upon the failure of that unknown design which was to take precedence of it; and he was most anxious to keep the door of communication open, that he might if possible discover what the former plan was. At the same time they could not resume their intermitted labours for the inundation without his finding it out; when by putting all hands to the work, the one existing outlet might in a single night be rendered impenetrable to any weight of water; for by filling the gang entirely up, their embankment would be buttressed by the sides of the mountain itself. As soon as he found that the goblins had again retired, he lighted his lamp, and proceeded to fill the hole he had made with such stones as he could withdraw when he pleased. He then thought it better, as he might have occasion to be up a good many nights after this, to go home and have some sleep. How pleasant the night air felt upon the outside of the mountain after what he had gone through in the inside of it! He hurried up the hill without meeting a single goblin on the way, and called and tapped at the window until he woke his father, who soon rose and let him in. He told him the whole story; and, just as he had expected, his father thought it best to work that lode no farther, but at the same time to pretend occasionally to be at work there still in order that the goblins might have no suspicions. Both father and son then went to bed and slept soundly until the morning. CHAPTER 10 The Princess's King-Papa