gripping account of those days and nights of superhuman effort
to hold back the enemy until reinforcements arrived, had the boys
neglecting their dinner and sitting on the edges of their chairs.

Mr. Hampton was a radio enthusiast. It was his interest in radio
development, in fact, which had caused him to build the station on
his estate, for purposes of trans-oceanic experiment. Eventually,
therefore, the talk came around to the subject of radio. Colonel
Graham was well-informed, and he told of several army officers then at
work on behalf of the government at Massachusetts Institute of
Technology, experimenting with radio-controlled automobiles, tanks and
water craft.

An exclamation from Jack drew attention to him and covered him with
confusion.

"Well, Jack," said his father, in mild reproof. And he looked
expectantly at his son as if awaiting an explanation.

Frank came to his rescue. His quick mind also had grasped the
significance of Colonel Graham's remark.

"I know what Jack is thinking of, Mr. Hampton," he said. "He's
thinking of a radio-controlled airplane."

Colonel Graham smiled.

"Oh, yes," he said, tolerantly. "I mentioned only that these
government experts were experimenting with radio-controlled
automobiles, tanks and water craft. Of course, airplanes are being
studied, too. Is that what you mean?" he asked, looking inquiringly at
Jack. "I understand you lads are interested in flying."

"No, sir," answered Jack, flushing a bit. "To tell you the truth, we
saw a plane to-day of strange design. And we had reason to believe it
was controlled by radio. I was puzzled at the time. I didn't think of
radio controls. But your remarks about the officers at Massachusetts
Tech. were illuminating. I see now that this plane must have been
radio-controlled."

Frank and Bob nodded approval. Their eyes were shining. Mr. Hampton,
Mr. Temple and Colonel Graham showed startled interest. Della leaned
forward close to Frank and looked at him reproachfully, a hand on his
arm.

"And you never told me a thing about it," she said.

"Didn't have any time to tell you," whispered Frank, in an undertone.

Mr. Hampton was speaking.

"Where did you see this plane, Jack?"

"Well, Dad," said Jack, "it was this way." Then he paused and looked
at his chums. "Shall I tell?"

"Go ahead, Jack," urged Frank.

Bob nodded approval.

With that Jack told as briefly as possible the circumstances of their
day's adventure, and