John and Fleury were standing near noon at the edge of the wood, when a small body of Uhlans halted close by.  Being not more than fifty in number, John judged that they were scouts, and the foaming mouths of their horses showing that they had been ridden hard, confirmed him in the opinion.  They were only fifty or sixty yards from him, and although they were motionless for some time, their eager faces showed that they were waiting for some movement.

It was pure chance, but John happened to be looking at a rather large man who sat his horse easily, his gloved hand resting on his thigh.  He saw distinctly that his face was very ruddy and covered with beads of perspiration.  Then man and horse together fell to the ground as if struck by a bolt of lightning.  The man did not move at all, but the horse kicked for a few moments and lay still.

There was a shout of mingled amazement and horror from the other Uhlans, and it found its echo in John’s own mind.  He saw one of the men look up, and he looked up also.  A dark shape hovered overhead.  Something small and black, and then another and another fell from it and shot downward into the group of Uhlans.  A second man was hurled from his horse and lay still upon the ground.  Again John felt that thrill of horror and amazement.

“What is it?  What is it?” he cried.

“I think it’s the steel arrow,” said Fleury, pressing a little further forward and standing on tiptoe.  “As well as I can see, the first passed entirely through the head of the man and then broke the backbone of the horse beneath him.”

John saw one of the Uhlans, who had dismounted, holding up a short, heavy steel weapon, a dart rather than an arrow, its weight adjusted so that it was sure to fall point downward.  Coming from such a height John did not wonder that it had pierced both horse and rider, and as he looked another, falling near the Uhlan, struck deep into the earth.

“There goes the aeroplane that did it,” said John to Fleury, pointing upward.

It hovered a minute or two longer and flew swiftly back toward the French lines, pursued vainly a portion of the distance by the German Taubes.

“A new weapon of death,” said Fleury.  “The fighters move in the air, under the water, on the earth, everywhere.”

“The Uhlans are off again,” said John.  “Whatever their duty was the steel arrows have sent them on it in a hurry.”

“And we’re about to move too.  See, these batteries are limbering up preparatory to a withdrawal.”

Inside of fifteen minutes they were again marching eastward, though slowly and with the roar of battle going on as fiercely behind them as ever.  John heard again from some of the talk of the guards that the Germans had five armies along their whole line, but whether the one with which he was now a prisoner was falling back with its whole force he had no way of knowing.  Both he and Fleury were sure the prisoners themselves would soon cross the Marne, and that large detachments of the enemy would go with them.