"All right; crawl in here, and no funny tricks or we'll fill ye full o' lead." At the point of the bayonet he and his corporal crawled over the parapet. They found themselves in the enlarged end of a sap that was being used as a listening post. In the darkness they could dimly see that they were surrounded by soldiers with fixed bayonets. "What's yer name?" hissed the voice, for out there no one is anxious to attract a hand grenade from the enemy on the other side of the line. "Lieutenant Weston." "An' yours?" to the corporal. "Corporal Easton." "Weston--Easton; that's too damn thin. Now you fellows march ahead of us to Headquarters, an' if ye so much as turn yer head we'll put so many holes through ye, ye'll look like a sieve. Quick march!" And they plowed through the deep mud of the trenches till they were well back, then they came out and proceeded overland to H.Q.--headquarters. Here, after a few sharp questions, a little telephoning, and some hearty laughter, they were given a runner to show them the shortest route back to their own battalion. Trench warfare as it has been carried on during this great war is different from the warfare of the past. Here we had--and have at the time of writing--on the western front alone, a fighting line five hundred miles long, with millions of the soldiers of the Allies occupying trenches, dugouts, huts, tents, and billets, on one side of the line, and the millions of the enemy in the same position on the other. For months at a time there is no move in either direction. Trenches are merely long, irregular ditches, usually, though not always, deep enough to hide a man from the enemy. Occasionally they are so shallow that the soldier must travel on his stomach, during which time any part of his anatomy which has too prominent a curve may be exposed to the fire of the enemy. Of course this all depends on the architectural configuration of the traveler. Except trenches far in the rear, they are always zigzag, being no more than ten to twenty feet in a straight line, to prevent any shell's doing too much damage. The front trench is called the firing line; the next one, fifty yards or so behind, but running parallel, is a support trench; and other support trenches exist back to about 1000 yards. Communicating trenches run from front to rear, crossing the support trenches. Here and there a communicating trench runs right back out of the danger zone, and these long trenches are at times divided into "in" trenches, and "out" trenches. Shorter communicating trenches run from support to firing lines. These different trenches give the ground, from above, the appearance of an irregular checker board.