But the Boches had done more than that. Their heavy guns were being sent around either side of the base of the mountain, each quota being part of a good-sized army. But they were sending another strong detachment up and over the mountain itself! And the first section of it was less than a mile below, spreading out in such a way that while a part of it would come over the top, other parts would go around either side, and they would be fan-like in shape, forming a virtual comb in the search for any enemies who might be lurking there. "The pack-set!" ordered the lieutenant. In a very short time it was set up, and Jerry was grinding the crank to generate power while the officer flashed out the headquarters call. In a moment a message began to come: "J-X. J-X. J-X. J-X." Lieutenant Mackinson nervously began tapping the key again, but the only reply was the insistent call for J-X, which was the code call for themselves. "No use," said the young officer at last. "We can catch them, with their stronger range, but we haven't radius enough to send to them." "Those troops cannot reach here until after dark," said Slim. "No," Lieutenant Mackinson acknowledged, "but they are in such numbers that we could not hope to keep our identity or presence hidden, and they are getting around the mountain quicker than we could get down and beyond their line." "It looks as though we were hemmed in," said Frank Hoskins in an even tone. "Yes," agreed Jerry, "and in a tight place." CHAPTER XVII THE LIEUTENANT'S INVENTION While the others speculated upon various means of escape, and in turn found every one of their suggestions useless, Lieutenant Mackinson had remained silent and in deep thought. Finally, his countenance showing that he had arrived at a conclusion, he turned to the others. "Come with me," he said simply, "it is the only way." "Where are you going?" Joe asked quickly. "Back to the tractor," the lieutenant replied. "Hurry! We still have time, but none to waste." "But we can't repair the tractor," Frank argued. "No, we can't," Lieutenant Mackinson admitted, "but we may do something even better than that." "What?" queried all the lads at once. "Come with me and we'll see what can be done." And without granting them any further information then, Lieutenant Mackinson swung his share of the burdens to his shoulder and started down the rough mountain road, the others following, and likewise bearing the various necessities which, only a short time before, they had labored so industriously to carry up the mountain. As they neared the point where they had left the wrecked machine the young officer turned to Joe, who was nearest to him. "Do you remember," he asked, "seeing that wire of the old telegraph line just about a hundred yards below where we ran the truck into the wall?" "I saw it," Joe admitted, "but I didn't pay any further attention to it." The others had come up within hearing distance.