"Were the Allies in their turn assaulting the Boches? What could it mean? In another brief interval Blaine found out, when sudden demoralization set in at once. Without apparent cause the Boches, now nearly upon the first Allied trenches, found that they were the center of a bombardment from the rear. What did that mean? The fire was withering.
Could the foe they were attacking be taking them in the flank? The idea was almost unbelievable. And yet the fire was also insupportable.
With one accord the front lines recoiled, although their officers beat the privates with their sword flats, cursing and reviling them as cowards. Right on top of this, the queer noises in front materialized into certainties.
The Allies were advancing. Were there not also reinforcements behind? Reinforcements hitherto kept back by what? The barrage. Where was that barrage now? Falling not only on their rear but also further back. How did this happen? Where were their own planes?
Officers and men were dropping on every hand. A charging foe in front was almost on them. After a minute or two of this, that whole section of the advance appeared to melt like froth on the water.
Meantime up above, and from a higher altitude than before, Bangs continued his mysterious signaling; not to Blaine or to the Allies, but — wonder of all wonders — to the Boches themselves.
Blaine now understood this, for he had noticed that the barrage itself had fallen back. Instead of covering and protecting the Germans, it was slaughtering them even more than the two aviators had done with their machine guns from a lower altitude.
Upon the sudden rout below, which was sensed rather than seen by the two fliers as the dawn rapidly grew, came the new rush of the Allies.
By this time Blaine felt that he and Buck must do one of two things. Those retreating observation planes would undoubtedly bring up air reinforcements. The barrage had already stopped. This was good for the charging Allies as well as the retreating Boches.
"Buck and I have either got to get back inside our lines or fight," he thought, carefully balancing his triplane against a rising breeze. "Or we might rise higher and take another chance. One thing we have done. We've helped bust up that charge, no matter how their advance has fared at Appincourte or elsewhere."