The artillery fire, constant for the last twenty-four hours, was increasing in violence. The guns of all sizes, from the giant twelve-inch to the fifteen-pounders, were belching forth their hail of devastating projectiles upon the enemy trenches. Vainly the German guns attempted to reply. Literally pulverized by an immensely superior weight of metal, their efforts were hardly of consequence. "Does a fellow good to see that," observed a grey-haired major, as he watched the incessant glare of the shells bursting in the Hun trenches. "We're top-dog now. I remembered at Ypres we were battered for a week or more and hardly able to reply. Now the boot is on the other foot, and, you fellows, wait till the morning. We've a nice little surprise for Fritz." There was no sleep that night for the officers and men of the Tanks. All inclination to rest was dispelled by the stupendous violence of the bombardment. The night was rendered as light as day by the incessant flashes, the din was indescribable, while the earth trembled with the crash of the guns. Rapidly the "dump" diminished, but as fast as the reserve of stacked shells was exhausted more were brought up. The dragon's teeth of ancient Greek mythology were not in it: the projectiles at the disposal of the hardworked but enthusiastic gunners were greater in number as the hours sped. Thanks to the splendid organization of the munition workers at home, the artillery was not in danger of being starved. "There won't be any work left for us to do," remarked Danvers. "The German trenches must be flattened out by this time." "You'll soon see," rejoined a lieutenant, consulting his watch. "It's now close on five. The infantry go over the top at the half-hour. Hullo! here's the C.O. It's about time we started." Already the men had stripped the canvas coverings from the massive mobile fortresses. The roar of the exhausts almost drowned the thunder of the guns. The air reeked with petrol vapour, mingled with the acrid, pungent fumes from the cordite charges from the nearest batteries. "All correct, sir," replied Ralph's sergeant, as the subaltern scrambled through the narrow armoured door in the afterside of the sponson and gained the complicated interior of the Tank. Setley gave the word and the mammoth ambled off, fifty yards in the wake of another Tank, three others following at regular intervals. It was still night. Dawn was close at hand, but any indications of the break of day were concealed by the huge clouds of smoke that hung in impenetrable curtains over the German lines. It was snowing. Frozen flakes were whirling through the smoke-laden air. In places the ground was covered to a depth of four or five inches, although everywhere the pure white mantle was rapidly churned into brownish slush by the constant movement of vehicles and men.