"That seems to prove it," said Tom. "Bad shooting though," remarked Frank, coolly. "Fritz ought to have the range better by this time." "There isn't very much of that sort of thing going on just now," remarked Corporal Wilson, who came along just then. "This is what they call a 'quiet sector.' The boys are just put here to be broken in and get used to the sight and sound of the shells. This is a deaf and dumb asylum compared to what you'll get later on." "Job's comforter," murmured Bart. "To hear the corporal talk you'd think this was a rest cure." In the hours of liberty allowed them the army boys explored the trenches for a long distance in either direction, and what they saw tended to upset a good many of the notions they had formed. In a vague way they had figured the trench to be not much else than a gigantic ditch. They found it to be an underground city. There was a bewildering labyrinth of passages branching off in every direction. There were spacious rooms, fitted up in homely comfort, some with pictures on the walls and rugs upon the floors. There were shower baths and laundries, rude in construction but efficient in operation. The sleeping quarters of the men consisted chiefly of bunks, rising in tiers, though in some cases, cots were used. There was an apparently endless series of communicating trenches with the listening posts in advance of the main line. There were telephone wires and electric lights. "The moles have got nothing on us," remarked Tom, as he noted the vast extent of these subterranean passages. "It's like the catacombs of Rome," put in Billy. "The only difference is that those contain dead men while we're very much alive." "Knock wood," counseled Bart. "We wouldn't be very long if the Boches had their way." Along the side of the main trench, facing the enemy was a narrow platform on which the men stood who were on watch. A series of cunningly contrived loopholes enabled them to look over at the enemy trenches without themselves being seen. Sand bags were piled on the top of the trench in numbers sufficient to stop the flight of a bullet or even the impact of a shell. A series of steps led up to the top and the boys reflected as they looked at them that before long their feet would be planted there when the order should be given to go "_over the top_" and charge across the intervening space to meet the enemy. The silent men standing on watch, gripping their muskets, their eyes peering through the loopholes, seemed like so many statues. Each had his gas mask ready to clap on at an instant's notice, for when that deadly poison should be wafted over the trench, one second of time might mean all the difference between life and death. Before the day was over Frank and his comrades had replaced this line of sentinels. They peered curiously across to the German trench from which they were separated by not more than two hundred yards.