"An hour to wait!" mused Bob, as he answered the officer who notified him. "A lot will be happening an hour from now." And the same thought was with all of them. "How many would be alive at this same time to-morrow night?" Slowly the seconds and minutes ticked themselves away. Silently the soldiers in the trenches made ready. And behind the lines preparations to support the advance, after the way was prepared for it by shells from the big guns, were going on. Silently groups of alert men gathered behind their officers in the traverses. The sentinels stood on the firing step, ready and waiting. Short ladders were placed here and there to facilitate the fighters in getting out of the sunken protections. Bob noted the illuminated minute hand of his watch creeping on toward the XII. "Sixty seconds more," he murmured. He glanced over toward Iggy. In the faint dawn he could see his Polish chum standing with his rifle, ready to leap from the trench. Then, suddenly, like a burst of thunder from a clear sky, the American barrage started, and after a sufficient time had elapsed the whistles sounded. "Over the top!" The old, familiar, but always thrilling call. "Over the top!" Out of the trenches leaped Bob, Iggy and their comrades. On toward the German lines they rushed, the half-darkness of the dawn now illuminated with the flashes from the big guns. The Germans were not long in replying. They were not taken by surprise, and soon a rain of H. E. shells, as well as shrapnel, began to deluge the American positions. But through this storm of missiles the gallant lads of the 509th Infantry leaped forward. They yelled and shouted, but they, each one, only heard his own voice, so great was the din of the guns. "Come on! Come on!" cried Bob hoarsely. But Iggy and his comrades needed no urging. They were rushing at the Germans like human tigers. They had heard so much and seen so much of the cruelty of the Huns that each time the Sammies went into battle it was as though they were taking personal revenge on the Kaiser's troops. Bob felt something, it was as if a great blast of air passed him. It lifted him from the earth and hurled him back, but he managed to regain his feet. Then came a terrible noise behind him--so far back that he was not harmed. But that could not be said for half a score of his comrades. A great shell exploded in their midst, and there were more than a score of casualties from it. "Close call!" murmured Bob as he staggered on. He lost sight of Iggy in the rush, but hoped the Polish lad was following closely. Then Bob had his hands full, for he and his immediate companions encountered some German machine-gun crews, and there was hard fighting before the Boches were killed or thrown into complete disorder. "Forward! Forward!" was the order, and well was it obeyed.