They had to watch their footing more and more to avoid falling into craters where the ground had been torn up by shells. There was no beauty in that part of fertile France that had once been like a "garden of the Lord." War had breathed upon it, blighting and blasting every living thing, except the dauntless spirit of the people who were fighting and would fight to the last gasp in defense of liberty and civilization. At last they reached a line of sentinels by whom they were greeted, not with challenges, but with exclamations of delight and welcome. A little further on they came to a great gash in the earth that stretched in either direction like a huge black, zigzag blot. They had reached the trenches! But they did not stop there. Onward they went again, past another line of trenches. "Gee! we must be going to the first line of trenches!" whispered Bart. "That's what!" answered Frank. CHAPTER XXIII FACING THE HUN Just this side of one of the lines of trenches the regiment halted at the word of the commander. Then it stood at attention and presented arms while from out the trenches came an endless line of men who had held that trench for France and now were yielding their place to the ardent young soldiers of the sister republic across the sea. There was a strong impulse to cheer on both sides, but that might have betrayed to the enemy the change that was taking place in that sector of the line, and this for strategic reasons, it was desirable to avoid. Soon the last of the war-worn veterans was lost in the darkness. Then, with infinite caution the boys of the old Thirty-seventh marched into the trenches, guided only by lanterns that waved low before them like so many fireflies. So perfectly the movement had been planned, so carefully had been mapped out in advance the exact location that each unit of the command was to occupy, that, within an hour after the substitution had been made, the entire regiment was placed, and, apart from those detailed for duty, was sound asleep! Curiosity ran riot when the army boys woke in their unfamiliar surroundings. At last they had reached the trenches, that magic word that they had heard again and again in the daily discussions of the last three years, and they studied every detail of their new surroundings with the keenest interest and zest. Here they were to live, here some of them, beyond a question, were to die. The thought was sobering, and on that first day there was little of the gaiety and jest that had marked their life in the camps behind. "Well, Bart, old scout, we're in for it now," said Frank, after breakfast, as he placed his hand on his friend's shoulder. "In for fair," responded Bart. "We're up against the real thing," added Billy. "We had a little taste of trench life down in Mexico, but most of the life was in the open. This is a different proposition." Just then a shell came screaming overhead and the boys involuntarily ducked.