“Ah, they can shut it off,” he said. “That’s interesting. I must investigate, and learn whether or no there is communication between the cells. Not very likely, though.” He crawled on hands and knees until he came to the bed of the stream, which was now damp, but empty. Kneeling down in its course, he worked his way toward the lower cell, and, as he expected, came to stout iron bars. Crouching thus he sacrificed a second match, and estimated that the distance between the two cells was as much as ten feet of solid rock, and saw also that behind the perpendicular iron bars were another horizontal set, then another perpendicular, then a fourth horizontal. While in this position he was startled by a piercing scream to the rear. He backed out from the tunnel and stood upright once more. He heard the sound of people splashing round in water. The screamer began to jabber like a maniac, punctuating his ravings with shrieks. Another was cursing vehemently, and a third appealing to the saints. Lermontoff quickly knelt down in the watercourse, this time facing the upper cell, and struck his third match. He saw that a steel shield, reminding him of the thin shutter between the lenses of a camera, had been shot across the tunnel behind the second group of cross bars, and as an engineer be could not but admire the skill of the practical expert who had constructed this diabolical device, for in spite of the pressure on the other side, hardly a drop of water oozed through. He tried to reach this shield, but could not. It was just beyond the touch of his fingers, with his arm thrust through the two sets of bars, but if he could have stretched that far, with the first bar retarding his shoulder, he knew his hand would be helpless even if he had some weapon to puncture the steel shield. The men would be drowned before he could accomplish anything unless he was at the lever in the passage outside. Crawling into his cell again he heard no more of the chatter and cries of the maniac, and he surmised that the other two were fighting for places on bench or shelf, which was amply large enough to have supported both, had they not been too demented with fear to recognize that fact. The cursing man was victorious, and now he stood alone on the shelf, roaring maledictions. Then there was the sound of a plunge, and Lermontoff, standing there, helpless and shivering, heard the prisoner swim round and round his cell like a furious animal, muttering and swearing. “Don’t exhaust yourself like that,” shouted Lermontoff. “If you want to live, cling to the hole at either of the two upper corners. The water can’t rise above you then, and you can breathe till it subsides.” The other either did not hear, or did not heed, but tore round and round in his confined tank, thrashing the water like a dying whale. “Poor devil,” moaned Jack. “What’s the use of telling him what to do. He is doomed in any case. The other two are now better off.”