His enthusiasm increased still further when he observed that the roof of the tunnel was supplied with ventilating-shafts. But at last Paul enjoined him to keep silent or to speak in a whisper: "You can imagine that, as they thought fit to preserve their lines of communication, they must have done something to make them unserviceable to the French. Èbrecourt is not far off. Perhaps there are listening-posts, sentries posted at the right places. These people leave nothing to chance." One thing that lent weight to Paul's remark was the presence, between the rails, of those cast-iron slabs which covered the chambers of mines laid in advance, so that they could be exploded by electricity. The first was numbered five, the second four; and so on. Paul and Bernard avoided them carefully; and this delayed their progress, for they no longer dared switch on their lamps except at brief intervals. At about seven o'clock they heard or rather they seemed to hear confused sounds of life and movement on the ground overhead. They felt deeply moved. The soil above them was German soil; and the echo brought the sounds of German life. "It's curious, you know, that the tunnel isn't better watched and that we have been able to come so far without accident." "We'll give them a bad mark for that," said Bernard. "Kultur has made a slip." Meanwhile a brisker draught blew along the walls. The outside air entered in cool gusts; and they suddenly saw a distant light through the darkness. It was stationary. Everything around it seemed still, as though it were one of those fixed signals which are put up near a railway. When they came closer, they perceived that it was the light of an electric arc-lamp, that it was burning inside a shed standing at the exit of the tunnel and its rays were cast upon great white cliffs and upon little mounds of sand and pebbles. Paul whispered: "Those are quarries. By placing the entrance to their tunnel there, they were able to continue their works in time of peace without attracting attention. You may be sure that those so-called quarries were worked very discreetly, in a compound to which the workmen were confined." "What Kultur!" Bernard repeated. He felt Paul's hand grip his arm. Something had passed in front of the light, like a shadow rising and falling immediately after. With infinite caution they crawled up to the shed and raised themselves until their eyes were on a level with the windows. Inside were half a dozen soldiers, all lying down, or rather sprawling one across the other, among empty bottles, dirty plates, greasy paper wrappers and remnants of broken victuals. They were the men told off to guard the tunnel; and they were dead-drunk. "More Kultur," said Bernard. "We're in luck," said Paul, "and I now understand why the watch is so ill-kept: this is Sunday."