“I wish you luck in your undertaking!” Mr. Havens said as the young man turned away, “and the only advice I give you at parting is that you take good care of yourself and Jimmie and enter upon no unnecessary risks!”

“That’s good advice, too!” smiled Sam, and the two parted with a warm clasp of the hands.

After leaving the millionaire aviator at the telegraph office, Sam hastened to the hotel where the boys were quartered and called Jimmie out of the little group in Ben’s room. They talked for some moments in the corridor, and then Jimmie thrust his head in at the half-open door long enough to announce that he was going out with Sam to view the city. The boys were all on their feet in an instant.

“Me, too!” shouted Ben.

“You can’t lose me!” cried Carl.

Glenn was at the door ready for departure with the others.

“No, no!” said Sam shaking his head. “Jimmie and I are just going out for a little stroll. Unfortunately I can take only one person besides myself into some of the places where I am going.”

The boys shut the door with a bang, leaving Carl on the outside. The lad turned the knob of the door and opened and closed it to give the impression that he, too, had returned to the apartment. Then he moved softly down the corridor and, still keeping out of sight, followed Sam and Jimmie out in the direction of the field where the machines had been left.

The two conversed eagerly, sometimes excitedly during the walk, but of course, Carl could hear nothing of what was being said. There was quite a crowd assembled around the machines, and so Carl had little difficulty in keeping out of sight as he stepped close to the Ann. After talking for a moment or two with one of the officers in charge of the machines, Sam and Jimmie leaped into the seats and pushed the starter.

As they did so Jimmie felt a clutch at his shoulders, and then a light body settled itself in the rather large seat beside him.