“What is the meaning of this?” he demanded.

The French officer turned upon him.

“None of your business,” he replied.  He turned and rapped on the door again.  “Open the door,” he commanded, “or I shall break it in.”

“Hold on there!” said Uncle John.  “I have the key to the door.  Tell me what you want with those young men and I’ll unlock the door.”

“I am ordered to take them before General Gallieni at once,” said the officer more civilly.

“The military governor!” exclaimed Uncle John.

“Exactly, monsieur,” said the officer, “and now, as you have the key, will you please to unlock the door immediately?”

“But what does the general want with them?” asked Uncle John anxiously.

“I cannot say,” was the reply.  “Will you unlock the door or shall I be compelled to use force?”

Without further words Uncle John unlocked the door, and the officer, followed by two of his men, strode in.  They approached the two lads.

“You are under arrest,” said the officer briefly.

Mrs. Paine and Mrs. Crawford attempted to reach their sons, but the soldiers barred their progress.

“Don’t worry, mother,” said Hal, as they were led by, and he smiled.

Uncle John caught the smile and a great light dawned upon him.

“Well, by George!” he said to himself, “I didn’t think they had it in ’em.”

He allayed the fears of the anxious mothers by telling them what he had discovered.

CHAPTER XXII.

INTO THE UNDERWORLD.

Hal did not see the look of understanding upon Uncle John’s face, as they were led along, but Chester did.  He smiled to himself.

“Uncle John has caught on,” he said to his friend.

“Caught on?” echoed Hal.

“Yes.  He knows that we have hoodwinked him.”

“So much the better, then,” said Hal.  “It will save our mothers some worry.”  He turned to the officer who conducted them as soon as they were out on the street.  “It’s all right now,” he said.  “We can go the rest of the way alone.”

“Perhaps you can,” was the reply, “but you won’t.  You’ll come right along with us.”

“But,” protested the lad, “we must first go to our other hotel and get the clothes we have secured for our work.”

“You will have to talk to General Gallieni about that,” said the officer gruffly.

“But General Gallieni knows all about our plans.”

“Does he?  I’m not so sure.  However, I guess he will before long?”

“Look here,” said Hal, “what’s the matter with you?”

“Come, now,” said the officer, “that’s enough of that.  March.”

Chester broke into a laugh, and Hal glanced at him in surprise.

“What are you laughing at?” he demanded.

“Why,” said Chester, “I am laughing because you can’t see through this.”