eemed to be desperately busy.
Men were rushing this way and that with stretchers, carrying wounded
soldiers back and forth. Vehicles were coming and going, and these
seemed of all descriptions, from the customary ambulance to big lorries
run with a motor; and all of them bore the sign of the Red Cross on
their sides, in order to protect them as much as possible from the fire
of the enemy.

It was in this manner therefore that the three Motorcycle Boys found
themselves entering a new phase of their extraordinary adventures, and
one that would doubtless never be forgotten, even when they found
themselves once again safe in their distant homes.

CHAPTER XIV.

WHERE THE BATTLE OF THE MARNE RAGED.

"Look, an aeroplane coming this way!" exclaimed Hanky Panky, pointing
upwards.

"If you glance off yonder," added Josh, "you'll see more than one of the
same. They're hanging over the battle lines, and I guess sending signals
back to tell what the observer notes from his perch away up aloft."

"Just what they're doing, Josh," Rod went on to say, as he stopped for a
brief time to take a look in the direction indicated.

In fact, they could make out as many as half a dozen of the fliers, some
darting about as swift as swallows on the wing, others more stationary,
and evidently with the operators busily engaged transmitting signals.

"There, see that one dropping something white!" cried Hanky Panky;
"chances are he's giving the gunners on his side a tip, so they can get
the range of the German battery, and put it out of action with a
volley."

"And there's going to be something doing pretty soon, or I miss my
guess," added Josh, excitedly; "because there comes a pair of those
Taube machines bent on giving the French ones battle. Rod, we're going
to watch a fight in the sky, don't you see? Whee! but this _is_ the
life, take it from me. I never dreamed I'd be so lucky as to be right on
the lines when a big battle was taking place."

The pair of Taube machines came swiftly along to engage the rival
aeroplanes that had been making so free with the secrets of the German
defences. Evidently the aviators had been ordered to put a stop to the
operations of the French pilots, no matter at what cost to themselves.

"They're shooting at each other now!" cried Josh; "you can see the puffs
of smoke break out every second; and it's different from the bursting of
shrapnel shells all around them."

"Gee! whiz! but this is awfu