"My dear chap, if you'll just be kind enough to lend me for one hour four strong men armed with picks and shovels, I shall be at Èbrecourt to-night." "I say! Four men to dig a six-mile tunnel through the rock in an hour!" "That's ample. Also, you must promise absolute secrecy both as to the means employed and the rather curious discoveries to which they are bound to lead. I shall make a report to the general commanding in chief; but no one else is to know." "Very well, I'll select my four fellows for you myself. Where am I to bring them to you?" "On the terrace, near the donjon." This terrace commands the Liseron from a height of some hundred and fifty feet and, in consequence of a loop in the river, is exactly opposite Corvigny, whose steeple and the neighboring hills are seen in the distance. Of the castle-keep nothing remains but its enormous base, which is continued by the foundation-walls, mingled with natural rocks, which support the terrace. A garden extends its clumps of laurels and spindle-trees to the parapet. It was here that Paul went. Time after time he strode up and down the esplanade, leaning over the river and inspecting the blocks that had fallen from the keep under the mantle of ivy. "Now then," said the lieutenant, on arriving with his men. "Is this your starting-point? I warn you we are standing with our backs to the frontier." "Pooh!" replied Paul, in the same jesting tone. "All roads lead to Berlin!" He pointed to a circle which he had marked out with stakes, and set the men to work: "Go ahead, my lads." They began to throw up, within a circle of three yards in circumference, a soil consisting of vegetable mold in which, in twenty minutes' time, they had dug a hole five feet deep. Here they came upon a layer of stones cemented together; and their work now became much more difficult, for the cement was of incredible hardness and they were only to break it up by inserting their picks into the cracks. Paul followed the operations with anxious attention. After an hour, he told them to stop. He himself went down into the hole and then went on digging, but slowly and as though examining the effect of every blow that he struck. "That's it!" he said, drawing himself up. "What?" asked Bernard. "The ground on which we are standing is only a floor of the big buildings that used to adjoin the old keep, buildings which were razed to the ground centuries ago and on the top of which this garden was laid out." "Well?" "Well, in clearing away the soil, I have broken through the ceiling of one of the old rooms. Look." He took a stone, placed it right in the center of the narrower opening which he himself had made and let it drop. The stone disappeared. A dull sound followed almost immediately. "All that need now be done is for the men to widen the entrance. In the meantime, we will go and fetch a ladder and lights: as much light as possible." "We have pine torches," said the officer. "That will do capitally."