“Firing about fifty cannon as fast as they can.  Back of the cannon is a great huddle of motors and of large automobile trucks, loaded, I should say, with ammunition.”

“You’re quite sure of what you say?” asked Lannes, after a silence of a moment or two.

“Absolutely sure.  I fancy that it’s an ammunition depot.”

“Then, John, you and I must take a risk.  We are to deliver a message, but we can’t let go an opportunity like this.  You recall how you threw the bombs on the forty-two centimeter.  I have more bombs here in the Arrow—­I never fly now without ’em—­little fellows, but tremendously powerful.  I shall dip and when we’re directly over the ammunition depot drop the bombs squarely into the middle of it.”

“I’m ready,” said John, feeling alternate thrills of eagerness and horror, “but Philip, don’t you go so near that if the depot blows up it will blow us up too.”

“Never fear,” said Lannes, laughing, not with amusement but with excitement, “I’ve no more wish to be scattered through the firmament than you have.  Besides, we’ve that message to deliver.  Do you think the Germans have noticed us?”

“No, a lot of smoke from their cannon fire has gathered above them and perhaps it veils us.  Besides, their whole attention must be absorbed by the French army, and I don’t think it likely that they’re looking up.”

“But they’re bound to see us soon.  We have one great advantage, however.  The target is much larger than the forty-two centimeter was, and there are no Taubes or dirigibles here to drive us off.  Ready now, John, and when I touch the bottom of my loop you throw the bombs.  Here they are!”

Four bombs were pushed to John’s side and they lay ready to his grasp.  Then as the Arrow began its downward curve, he laid his glasses aside and watched.  The most advanced German batteries were placed in a pit, into which a telephone wire ran.  Evidently these guns, like the French, were fired by order from some distant point.  John longed to hurl a bomb at the pit, but the chances were ten to one that he would miss it, and he held to the ammunition depot, spread over a full acre, as his target.

Now the Germans saw them.  He knew it, as many of them looked up, and some began to fire at the Arrow, but the aeroplane was too high and swift for their bullets.

“Now!” said Lannes in sudden, sharp tones.

The aeroplane dipped with sickening velocity, but John steadied himself, and watching his chance he threw four bombs so fast that the fourth had left his hands before the first touched the ground.  An awful, rending explosion followed, and for a minute the Arrow rocked violently, as if in a hurricane.  Then, as the waves of air decreased in violence, it darted upward on an even keel.

John saw far below a vast scene of wreckage, amid which lay many dead or wounded men.  Motors were blown to pieces and cannon dismounted.