“Wonderful!” exclaimed Elaine.  “That was very realistic.”

We brushed our way out through the thick palms, congratulating Kennedy on the perfect success of his demonstration.

So astonished were we that we did not hear the doorbell ring.  Jennings answered it and admitted two men.

“Is Professor Kennedy here?” asked one.  “We have been to his apartment and to the laboratory.”

“I’ll see,” said Jennings discretely, taking the card of one of them and leaving them in the drawing-room.

“Two gentlemen to see you, Mr. Kennedy,” Jennings interrupted our congratulations, handing Craig a card.  “Shall I tell them you are here, sir?”

Craig glanced at the card.  “I wonder what that can be?” he said, turning the card toward us.

It was engraved: 

W. R. Barnes U. S. Secret Service.

“Yes, I’ll see them,” he said, then to us, “Please excuse me?”

Elaine, Aunt Josephine and I strolled off in the palms toward the Fifth Avenue side, while Jennings went out toward the back of the house.

“Well, gentlemen,” greeted Kennedy as he met the two detectives, “what can I do for you?”

The leader looked about, then leaned over and whispered, “We’ve just had word, Professor, that your model of the torpedo has been stolen from the Navy Department in Washington.”

“Stolen?” repeated Kennedy, staring aghast.

“Yes.  We fear that an agent of a foreign government has found a traitor in the department.”

Rapidly Kennedy’s mind pictured what might be done with the deadly weapon in the hands of an enemy.

“And,” added the Secret Service man, “we have reason to believe that this foreign agent is using a Chinaman, Wu Fang.”

“But Wu has been arrested,” replied Craig.  “I arrested him myself.  The police have him now.”

“Then you don’t know of his escape?”

Kennedy could only stare as they told the story.

Suddenly, down the hall, came cries of, “Help!  Help!”

. . . . . . .

While Craig was showing us the torpedo, the criminal machinery which Wu had set in motion at orders from the foreign agents was working rapidly.

Outside the Dodge house, a man had shadowed us.  He waited until we went in, then slunk in himself by the back way and climbed through an open window into the cellar.

Quietly he made his way up through the cellar until finally he reached the library.  Listening carefully he could hear us talking in the conservatory.  Stealthily he moved out of the library.

We had left the conservatory when he entered, peering through the palms.  On he stole till he came to the fountain.  He looked about.  There, bobbing up and down, was the model of the torpedo for which he had dared so much.  He picked it up and looked at it, gloating.

The crook was about to move back toward the library, hugging the precious model close to himself when he heard Jennings coming.  He started back to the conservatory.  Jennings entered just in time to catch a fleeting glimpse of some one.  His suspicions were roused and he followed.