g to make a raid," observed Jack.

"Something like that--yes," assented Tom.

"Hope we're in on it, and the commanding officer doesn't have us take
some huns up to show 'em what makes the wheels go around," went on Jack.
"Of course that's part of the game, but we've done our share."

However, they need have felt no fear, for when they stood before the
commanding officer, saluting, they quickly learned that they were to go
on a special mission that day--in fact as soon as they could get ready.

"I want you two to see if you can discover a battery of small guns that
have been playing havoc with our men," he said, as he looked up from a
table covered with maps. "They're located somewhere along this front,
but they're so well camouflaged that no one has yet been able to
discover them.

"I want you boys to see if you can turn the trick. The guns have killed
a lot of our men, as well as the French and English. We've tried to rush
the emplacement, but we can't get a line on where it is for it's well
hidden. I asked permission of the British commanding general to send up
two American scouts, and he mentioned you boys. Get your orders from the
major, and good luck to you."

"Do you want us to go together or separately?" asked Tom.

"Together--in a double plane. I might say that we are going to try a
raid on a big scale over the enemy's lines, and you two will thus have a
better chance to carry out your observations unmolested. The Hun planes
will have their hands full attending to our fighters, and they may not
attack a single plane off by itself. We'll try to draw them away from
you.

"At the same time I might point out that there is nothing sure in this,
and that you may have to fight also," concluded the commanding officer,
as he waved a dismissal.

"Oh, were ready for anything," announced Tom. And as he and Jack got
outside he clapped his chum on the back, crying: "That's the stuff! Good
old C.O. to send us! That's what we've been looking for! Maybe we'll
have time to drop down and shoot some of the Huns that are guarding
Harry."

"No chance of that--forget it now," urged Jack. "We'll clean up this
location trick first, and then think of a plan to get Harry away. It
sounds hard to say it, but it's all we can do. Orders are orders."

They were glad they had made ready the speedy Spad plane, for it was
in this that they would try to locate the hidden battery, and, having
received detailed instructions from the maj