ng we didn't start," observed Ned.

"I should say so," agreed Tom. "But we'll get off the first thing in
the morning, dad."

Mr. Swift did not reply, but his nervous pacing to and fro in the hotel
office showed how anxious he was to be at home again. There was no
help for it, however, and, after a time, finding that to think of
reaching his house that night was out of the question, the inventor
calmed down somewhat.

The storm continued nearly all night, as Tom could bear witness, for he
did not sleep well, nor did his father. And when he came down to
breakfast in the morning Mr. Swift plainly showed the effects of the
bad news. His face was haggard and drawn and his eyes smarted and
burned from lack of sleep.

"Well, Tom, we must start early," he said nervously. "I am glad it has
cleared off. Is the boat all ready?"

"Yes, and it's a good thing it was under shelter last night or we'd
have to bail it out now, and that would delay us."

An hour later they were under way, having telephoned to the engineer at
the Swift home that they were coming. Garret Jackson reported over the
wire that he had notified the Shopton police of the robbery, but that
little could be done until the inventor arrived to give a description
of the stolen articles.

"And that will do little good, I fear," remarked Tom. "Those fellows
have evidently been planning this for some time and will cover their
tracks well. I'd like to catch them, not only to recover your things,
dad, but to find out the mystery of my boat and why the man took the
tank braces."

CHAPTER XXI

THE BALLOON ON FIRE

Down Lake Carlopa speeded the ARROW, those on board watching the banks
slip past as the motor-boat rapidly cut through the water.

"What time do you think we ought to reach home, Tom?" asked Mr. Swift.

"Oh, about four o'clock, if we don't stop for lunch."

"Then we'll not stop," decided the inventor. "We'll eat what we have
on board. I suppose you have some rations?" and he smiled, the first
time since hearing the bad news.

"Oh, yes, Ned and I didn't eat everything on our camping trips," and
Tom was glad to note that the fine weather which followed the storm was
having a good effect on his father.

"We certainly had a good time," remarked Ned. "I don't know when I've
enjoyed a vacation so."

"It's too bad it had to be cut short by this robbery," commented Mr.
Swift.

"Oh, well, my time would be up in a few days more," went