Two hundred feet away from that light Joe and Frank Hoskins lay prone upon the ground, silent, impatient, fearful, hoping. With a quick motion the artillery captain swung his outstretched arm downward. There was a roar, a flash, and a great shell tore through the air. Out in No Man's Land there was a second explosion as the shell hit, and the target--a flashlight--was blown to atoms. Over in the German trenches a sentinel chuckled at the thought of another wasted American shell, but out of the hole that that shell had torn three pale, haggard, and exhausted youths were crawling to safety and God's fresh air. And across No Man's Land dashed two pals to greet them. American determination and American marksmanship had saved three American lives. The German sentinel might have his laugh if he liked. It was hours later before the three who had been imprisoned learned how their rescue had been effected; but they got an inkling of it as they came within four hundred yards of the American-French front. "What are you doing?" Lieutenant Mackinson had asked, as Joe brought the party to a stop. "Just a moment and you will see," Joe had responded. And, first in wonder and then with a dawning understanding, the other three read off his flashed message: "Signal Corps men, and whole party safe." CHAPTER XV THE SURPRISE ATTACK--PROMOTION During the week that followed, the lads were confined almost entirely to regular routine work, with nothing particularly exciting. Frank Hoskins' elbow wound healed quickly, without any serious results; and Tom Rawle, who had been under treatment at the field hospital, was able to get about the camp, although still pale and weak, and limping considerably from his injury. But on the eighth day a veritable fury launched itself upon that section of the American-French front, in the shape of seemingly endless brigades of Boches that were hurled "over the top" of their own breastworks, across No Man's Land, and upon the first-line trenches of the Allies. For several days the American and French aviators had been reporting heavy German formations in that region, evidently with the design of a terrific assault, but the allied commanders had not expected it so soon, and in truth they were not fully prepared for it. It was a surprise attack in every sense of the word, with all the terrible carnage that such a battle brings. Shortly before midnight of the preceding night a terrible bombardment had been directed against the American-French trenches, and their hidden artillery to the rear of them. This was kept up for about seven hours, and the duel of heavy guns shook the earth like a quake and was deafening. Then, just as dawn was breaking, the infantry onslaught, participated in at some points by detachments of cavalry, began.