"I guess to-morrow's the big day," remarked Frank, as he looked out at the settling mists. "High time," grumbled Tom. "I'd grow stale if we had to wait much longer." The regiments slept on their arms that night, and an hour before dawn all were astir and in their places. There was no special artillery fire, such as usually preceded big attacks. It was given to the tanks to level the entanglements of the enemy and open up the gaps for the troops to swarm through. The hour dragged by until within ten minutes of the time appointed for the assault. Then a monotonous hum filled the air as the motors of the tanks tuned up. Down through the black lines of waiting soldiers the gray monsters slowly made their way, passed through the gaps made in the defences and led the way into the desolate stretch of No Man's Land. Even to the friendly eyes that watched them there was something weird and frightful in their aspect. It was as though the huge brutes of the prehistoric world had taken form before them. Even those monsters had never carried within them such death-dealing power. As the sea closes in the wake of a ship, the troops fell in behind the tanks, and the silent procession took up the march toward the German lines. Hardly a sound beyond the labored breathing of the tanks broke the stillness. It might have been an army of ghosts. On they went, and with every step the conviction grew that the surprise would be complete. No thunder broke from the enemy guns. No fiery barrage swept the dense ranks, exacting its toll of wounds and death. For once the Hun was asleep. Nearer and nearer. Then like so many thunderbolts at a hundred different points they struck the German lines and the tanks went through! CHAPTER XIII CAUGHT NAPPING Nothing could stand before the terrific impact of the war tanks. There was a grinding, tearing, screeching sound, as wire entanglements were uprooted. These had been strengthened in every way that German cunning could invent, but they bent like straws beneath the onslaught of the gray monsters. A cyclone could not have done the work more thoroughly. There was no need now for further secrecy, and with a wild yell the Allied troops swarmed through the gaps, sending a deadly volley before them, supplemented by thousands of grenades. At the same instant, the Allied artillery opened up and laid a heavy barrage fire over the heads of the onrushing troops. The blow came down on the Germans with crushing force. The surprise was complete. Every detail of the great drive had been mapped out with the precision of clockwork, and so nicely had it been timed that on every part of the long line the shock came like a thunderbolt. A horde of Germans rushed up from the trenches and poured in a great stream into the open. The earth seemed to disgorge itself. They came shouting and yelling in wild consternation, their eyes heavy with sleep and their faces pallid with fear.