ousness--that is, he was getting awake. It was
the morning after the successful discovery of the hidden German battery,
and since this exploit the two lads had not been required to go on duty.

"What's the matter?" asked Jack, opening his eyes and looking at his
chum. "Has the mail come in? Any letters?"

"No. I was just thinking," remarked Tom, and though his eyes were fixed
on Jack it was clear that his thoughts were somewhere else.

"Thinking, Tom? That's bad business. Have you seen the doctor?"

"Oh, shut off your gas!" ordered Tom. "You're side slipping. First you
know you'll come down in a tail spin and I'll have to be looking for a
new partner."

"It's as serious as all that, is it?" asked Jack, as he began to dress.
"Well, in that case I withdraw my observation. Go ahead. How's the
visibility?"

"Low. We won't have to go up to-day, unless it clears."

"Um. And I was counting on getting a few Huns right after breakfast.
Well, what's your think about, if you really were indulging in that
expensive pastime?"

"I was," said Tom, and he got up and also proceeded to put on his
clothes. "I was thinking about Harry."

"Oh!" and Jack's voice was decidedly different. It had lost all its
flippant tone. "Say, he certainly is in tough luck. I wish we could do
something for him--and his sister. Doubtless you were thinking of her,
too," and a little smile curled his lips.

"Yes, I was thinking of Nellie," conceded Tom, and he was so bold and
frank about it that Jack choked back the joke that he was about to make.
"I was thinking that we haven't done very much to redeem our promise."

"But how can we?" asked Jack. "We haven't had a chance to do anything to
rescue Harry. Of course I want to do that as much as you do, but how is
it to be done? Can you answer me that?"

"We can't do it by just talking," said Tom. "That's what I've been
thinking about. A scheme came to me in the night, and I've been waiting
to tell you about it."

"Shoot then, my pickled blunderbuss," returned Jack. "I'm with you to
the last drop of petrol."

"Well, I don't know that it's so much," said Tom. "It's only that we
ought to get word to Harry, somehow, that we're thinking of him and
trying to plan some way of rescuing him. We ought to tell him his sister
is here, too, and, at the same time we might drop him something to smoke
and a cake or two of chocolate."

Jack looked at his chum in amazement. Then he burst out with:

"Say, while y