“I shall be back to-morrow,” he said, “and have a look at Mortlake’s machines.  Of course, the government wants to give everybody a fair field and no favors.”

“Oh, of course,” assented Roy, pondering in his own mind what sort of a machine this mysterious Mortlake craft was.

Suddenly there flashed across his mind a thought that had not occurred to him hitherto.  The Golden Butterfly had been left under the shed at the farm.  What was there to prevent Harding and Mortlake from examining it and acquainting themselves with the intricacies of the self-starting mechanism and the automatic balancing device?

There was no question that the farm must have been their destination.  Roy blamed himself bitterly for not foreseeing this.  He had half a mind to return to the farm and bring the aeroplane home himself.  But it was growing dark, and a distant rumble seemed to presage the return of the afternoon’s storm.

“Anyhow,” the boy thought, and the thought consoled him, “all those devices are covered by patents, and even if they wanted to, they could not steal them.  And yet—­and yet——­”

But the storm came up sharper than ever that evening, and even had he wished to, Roy would have found it impossible to handle the aeroplane alone in the heavy wind that came now in puffs and now in a steady gale.  So Roy put his tiresome thoughts out of his head.  But he resolved to get the aeroplane the first thing the following morning.

CHAPTER VII.

A CASE FOR THE AUTHORITIES.

It was just after breakfast the next morning that a big automobile skimmed past the Prescott home.  Peggy and Roy saw it from the windows.

“Why, that’s Sheriff Lawley,” exclaimed Peggy.  “And look, old Mr. Harding is with him, and that Mortlake man.”

“That’s right.  Wonder where they can be going?” said Roy, sauntering out to the garage at the back of the house and giving the matter little more thought.  It had been arranged that he was to bring the aeroplane back that morning, driving over with Peggy, Jimsy and Jess in the car, and skimming home in the Butterfly while a part of the party brought the car back.  They were to call for Jess and Jimsy at their home, a fine residence overlooking the Sound from a lofty hill.

Jess and Jimsy were waiting for them, and, almost before the car had stopped, they were at its side.

“Heard the news?” asked Jimsy breathlessly.

“No.  What is it?” demanded Peggy eagerly.

“Why, that safe at the farm-house was robbed last night.  All the money was taken, and they have no clue to the thief.”

“How did you hear of it?” asked Roy incredulously.  Peggy had told him of the queer wall safe.

“The ‘central’ told one of the servants and she told Jess.  Strange, isn’t it?”

“It is odd,” agreed Roy.  “But if people will keep their money in such places, it is hardly surprising if they lose it.  Did you hear any details?”