Such a start had the Boches gotten, by somehow missing the Allied planes that were supposed to be picketing the front, that a direct attack was inevitable. Up or down they rose or fell, each plane singling out its opponent, and each maneuvering for position. It was here that the superior speed and nimbleness of the Allied triplanes was soon apparent. Byers in his big biplane made straight for the leading plane opposed to him and presently the rattle of machine gun fire interplayed with the whirring sounds of the motors, while the diving, flipping, looping, with all the other air stunts of sky battling, made the scene so interesting to those below that the adjacent bomb-proofs were hardly thought of. On a small knoll the American senator and his two daughters, glasses in hand, were watching, listening, semi-oblivious as to any possible danger to themselves. Finally a spatter of bullets and shell fragments roused the father to a sense that more than himself might be in the line of fire at any moment. "This won't do, girls!" he announced in peremptory tones. "Get into that shelter!" pointing at a half underground dugout near. "Run, run!" Avella, without lowering her glass, replied: "In just a minute, papa. See Mr. Blaine! My! What's he doing to that other horrid fellow?" Blaine was at the instant trying to got on the tail of a big Taube, not unlike the one Blaine and Erwin had captured and used while on an earlier scout, as may be recalled by the reader. What accentuated Blaine's eagerness was the glimpse he caught of that Death's Head Flag, which had also adorned the former captured machine. But the Boche within this one was an adept and so maneuvered that Blaine, to save himself from an onset from behind, was obliged to try the risky side-loop, much to the surprise of the other. For Blaine, while upside down, was already firing at his opponent, and as he rose was directly on the tail. But to the girls below it looked as if Blaine was already crashing towards the earth. Andra gave a nervous scream. Avella was shocked, of course, but had her glass the next instant upon Buck Bangs, at that moment engaged in a fierce duel with two enemy opponents. "Look! Look!" called Andra. "He's falling -- ah-h-h!" This last word was long drawn out during which, to her intense joy, Blaine had righted himself and was behind and below the other plane. Now she could see the spitting of lire as he plugged bullets and shrapnel into his astonished opponent. Scarcely did she breathe again before the Taube, its Death's Head Flag collapsing about its staff, was tumbling down, almost over them. At the same time one of the Huns battling with Bangs was hit in the tank by a rain of bullets from Byers' machine which was striving to rise above and behind the foe the captain had singled out for himself.