Ruth could not know then all that a break “through” meant; no one could know; for in all the fighting in France, no army had broken “through” before. She could know only that upon her, as an American quite as much as Gerry Hull, was the charge to do her uttermost. But what was she to do? Gerry, arriving that morning at the airdrome to which he had been ordered, possessed the advantage over her of no uncertainty but of definite assignment to duty. During his training and his service with the French, he had piloted many sorts of machines. He had flown the reconnaissance and photographic biplanes with duty merely to bring back information of the enemy’s movements; he had flown the bombing machines entrusted with destruction, by aerial torpedo, of batteries, and ammunition dumps behind the enemy’s front; he had flown the “artillery machines”--the biplanes with wireless by which he, or his observer, signaled to the French batteries the fall of their shots and guided the guns to the true targets; he had flown, as all the world knew, the swift-darting _avions de chasse_--the airplanes of pursuit--the Nieuports and the Spads in which, as combat pilot, he had dueled ten thousand feet up in the sky with the German combat pilots and shot some twenty of them down. And it was while he was still in the French service that the flying men began to form new squadrons for strange service distinct from mere bomb-dropping, from guiding guns or sending back information or from fighting other airplanes. Pilots of these squadrons started to attack, by bomb and machine guns, the enemy infantry and artillery and horse. They had special, new “ships” made for them--one-seater or two-seater biplanes mounting two or three machine guns and built to stand the strain of diving down from a height and “flattening out” suddenly only a few yards from the ground while the pilot with his machine guns raked the ranks of troops over which he flew. It was in one of these new raiding airplanes, accordingly, and as leader of a flight that Gerry Hull was going to battle this day. The field, from which he had arisen, had been far back of the English lines--so far back, indeed, that it still was secure as Gerry guided his flight of six machines up into the clear spring sunshine. His was one of the single-seaters; he was alone, therefore, as he led on to the north and east; and he was glad this morning to be alone. The exaltation which almost always pervaded him as he rose into the sky with his motor running powerfully and true, possessed him at its most this morning; it brought to him, together with the never-dulling wonder of his endowment of wings and his multiplied strength therefrom, a despite of fate which made him reckless yet calm.