op!" roared the German. And then came the crack!
crack! crack! of firearms.

The air service boys, because of the noise of the motor, did not hear
the discharge of the pistols, but suddenly Jack heard the spatter of a
bullet as it struck the machine close beside him. Then he ducked and
made a motion to Tom to let his chum know that they were under fire.

But the machine was gaining headway rapidly, and presently they were so
high that those below could no longer reach them. Up and up they went
until they were thousands of feet above the valley that had been the
scene of this remarkable adventure.

Tom headed back along the course he had just come. It was now easy to
pick up one landmark after another, and in due course of time they
passed over the lines once more. Of course, the sound of the plane's
propellers was heard by the Germans, and some shrapnel was sent after
them; but as Tom was careful to keep high in the air, this did not reach
them, and soon they were out of the danger belt.

Fifteen minutes later they made a landing, this time on the well
remembered aviation field of Bar-le-Duc. Here there were attendants on
hand ready to care for the machines.

"Glad to see you got back," said one of the attendants, grinning. He
knew that Tom had gone off on the second trip to bring Jack.

The two air service boys found a car to take them to the villa. The long
ride through the night air had made both of them very sleepy, and yet
neither felt just then like retiring.

"It's a lucky thing, Tom," said Jack, between yawns, "that I had this
fur-lined pilot's coat along with me. Only for that I'd have been mighty
cold out there in the open last night, with no chance for a fire."

"Well, it's all past now, Jack. Tell me what happened to you during my
absence."

Jack, was nothing loath, and as quickly as possible gave his chum the
particulars of how he had gone into hiding and almost been betrayed by
the dog.

Tom had already told Jack about what had become of Mrs. Gleason and
Bessie. They had been taken to a house some miles back of the lines, and
were to be made comfortable there for the night.

"And early in the morning they are to start for Paris," Tom said with
satisfaction. "I managed through our captain to get them passage aboard
a train that is to take some wounded back to the base hospitals. Mrs.
Gleason says she means to stay in Paris and help all she can as a Red
Cross nurse, for she has had some experien