."

"Unless he knew just where they were going to fall," said Jack.

"You have a reason for everything, I see," remarked Tom. "Well, the next
time we go to headquarters we'll find out what they learned of this
fellow. You know we started the secret service agents on his trail."

"Yes, I know. Well, I was just sort of wondering if he had anything to
do with the bombardment of Paris. You've got to look for German spies
now, even under your bed at night."

The boys felt they could do nothing more that day toward finding Mr.
Raymond. A more detailed and careful search of the ruins might reveal
something. Until this was accomplished nothing could be done.

They ate a late supper, without much in the way of appetites, it must be
confessed, and then went out in the streets of Paris. There seemed to be
few signs of war, aside from the many soldiers, and even the
bombardment of a few hours earlier appeared to have been forgotten. But
of course there was grief in many hearts.

It was early the next morning, when Tom and Jack were getting ready to
go back to the ruins in the Rue Lafayette, that, as they left their
lodgings, they heard in the air above them the familiar sounds of
aeroplanes in flight, and the faint popping of machine guns, to which
was added the burst of shrapnel.

"Look!" cried Jack. "It's a battle in the air. The Huns are making
another raid. Now we'll see how they bomb the city."

But it did not turn out to be that sort of raid. The German craft were
flying low, apparently to get a view of the havoc wrought the day
before. Possibly photographs were being taken.

But the French aeroplanes were ready for the foe, and at once arose to
give battle, while the anti-aircraft guns roared out a stern order to
retreat. It was a battle above the city and, more than once, Tom and
Jack wished they could be in it.

"We'll have to get back to our hangars soon," mused Tom, as they watched
the fight. "We can't be slackers, even if I can't find my father," he
added bravely.

The French planes were too much for the Germans, and soon drove them
back beyond the Hun lines, though perhaps not before the enemy aviators
had made the observations desired.

"Well, they didn't see much," remarked Jack. "As far as any real damage
was done to Paris it doesn't count, from a military standpoint."

"No, you're right," agreed Tom. "Of course they have killed some
noncombatants, but that seems to be the Boche's principal form of
a