Gourel did so. Behind the shutter, the wall was hollowed out. By the light of the lantern they saw an underground passage running downwards. "I was right," said M. Lenormand.. "The communication is of recent date. You see, it's a piece of work hurriedly done, and not intended to last for any length of time. . . . No masonry. . . . Two planks placed cross-wise at intervals, with a joist to serve as a roof; and that is all. It will hold up as best it may: well enough, in any case, for the object in view, that is to say . . ." "That is to say what, chief?" "Well, first to allow of the going backwards and forwards between Gertrude and her accomplices . . . and then, one day, one day soon, of the kidnapping, or rather the total, miraculous, incomprehensible disappearance of Mrs. Kesselbach." They proceeded cautiously, so as not to knock against certain beams which did not look over-safe. It at once became evident that the tunnel was much longer than the fifty yards at most that separated the house from the boundary of the garden. It must, therefore, end at a fair distance from the walls and beyond the road that skirted the property. "We are not going in the direction of Villeneuve and the lake are we?" asked Gourel. "Not at all, the other way about," declared M. Lenormand. The tunnel descended with a gentle slope. There was a step, then another; and they veered toward the right. They at once knocked up against a door which was fitted into a rubble frame, carefully cemented. M. Lenormand pushed it and it opened. "One second, Gourel," he said, stopping. "Let us think. . . . It might perhaps be wiser to turn back." "Why?" "We must reflect that Ribeira will have foreseen the danger and presume that he has taken his precautions, in case the underground passage should be discovered. Now he knows that we are on his track. He knows that we are searching the garden. He no doubt saw us enter the house. How do I know that he is not at this moment laying a trap for us?" "There are two of us, chief. . . ." "And suppose there were twenty of them?" He looked in front of him. The tunnel sloped upward again, closed by another door, which was at five or six yards' distance. "Let us go so far," he said. "Then we shall see." He passed through, followed by Gourel, whom he told to leave the first door open, and walked to the other door, resolving within himself to go no farther. But this second door was shut; and though the lock seemed to work, he could not succeed in opening it. "The door is bolted," he said. "Let us make no noise and go back. The more so as, outside, by remembering the position of the tunnel, we can fix the line along which to look for the other outlet." They therefore retraced their steps to the first door, when Gourel, who was walking ahead, gave an exclamation of surprise: "Why, it's closed! . . ." "How is that? When I told you to leave it open!"