of clothes.

"So you are spying on my house, are you?" he said. "And you lied to me
yesterday! No troops were sent to Croydon at all!"

"Well, you hadn't any business to ask us!" said Dick, pluckily. "If you
hadn't asked us any questions, we'd have told you no lies."

"I think perhaps you know too much," said the spy, nodding his head. "You
had better come with me. We will look after you in this house that
interests you so greatly."

He made a movement forward. His hand dropped on Dick's shoulder. But as it
did so Harry's feet left the ground. He aimed for the spy's legs, just
below the knee, and brought him to the ground with a beautiful diving
tackle--the sort he had learned in his American football days. It was the
one attack of all others that the spy did not anticipate, if, indeed, he
looked for any resistance at all. He wasn't a football player, so he didn't
know how to let his body give and strike the ground limply. The result was
that his head struck a piece of hard ground with abnormal violence, and he
lay prone and very still.

"Oh, that was ripping, Harry!" cried Dick. "But do you think you've killed
him?"

"Killed him? No!" said Harry, with a laugh. "He's tougher than that, Dick!"

But he looked ruefully at the spy.

"I wish I knew what to do with him," he said. "He'll come to in a little
while. But--"

"We can get away while he's still out," said Dick, quickly. "He can't
follow us and we can get such a start with our motorcycles--"

"Yes, but he'll know their game is up," said Harry. "Don't you see, Dick?
He'll tell them they're suspected--and that's all they'll need in the way
of warning. When men are doing anything as desperate as the sort of work
they're up to in that house, they take no more chances than they have to.
They'd be off at once, and start up somewhere else. We only stumbled on
this by mere accident--they might be able to work for weeks if they were
warned."

"Oh, I never thought of that! What are we to do, then?"

"I wish I knew whether anyone saw us from the house! If they didn't--!
Well, we'll have to risk that. Dick, do you see that house over there? It's
all boarded up--it must be empty."

"Yes, I see it." Dick caught Harry's idea at once this time, and began
measuring with his eye the distance to the little house of which Harry had
spoken. "It's all down hill--I think we could manage it all right."

"We'll try it, anyhow," said Harry. "But first we'd better tie up his h