ns that night to try to
follow us."

"It would be just like him," returned Ned, "but I don't think
they'll do it. They haven't enough information to go on. More likely
Mr. Foger is going to try some new ventures to get back his lost
fortune."

"Well, I hope he and Andy keep away from us. They make trouble
everywhere they go. Now come on, get busy."

And, though Tom tried to drive from his mind the thoughts of the
Fogers, yet it was with an uneasy sense of some portending disaster
that he went on with the work of preparing for the trip into the
unknown. He said nothing to Ned about it, but perhaps his chum
guessed.

"That'll do," said Tom after an hour's labor. "We'll call it a
night's work and quit. Can't you stay here--we've got several spare
beds."

"No, I'm expected home."

"I'll walk a ways with you," said Tom, and when he had left his chum
at his house our hero returned by a street that would take him past
the Foger residence. It was shrouded in darkness.

"Everybody's cleared out," said Tom in a low voice as he glance at
the gloomy house. "Well, all I hope is that they don't camp on our
trail."

CHAPTER VIII

ERADICATE WILL GO

"I guess everything is all ready," remarked Tom.

"I can't think of anything more to do," said Ned.

"Bless my grip-sack!" exclaimed Mr. Damon, "if there IS, someone
else has got to do it. I'm tired to death! I never thought getting
ready to go off on a simple little trip was so much work. We ought
to have made the whole journey from start to finish in an airship,
Tom, as we've done before."

"It was hardly practical," answered the young inventor. "I'm afraid
we'll be searching for this underground city for some time, and
we'll only need an airship or a dirigible balloon for short trips
here and there. We've got to go a good deal by information the
natives can furnish us, and we can't get at them very well when
sailing in the air."

"That's right," agreed the eccentric man. "Well, I'm glad we're
ready to start."

It was the evening of the day before they were to leave for New
York, there to take steamer to a small port on the Mexican coast,
and every one was busy putting the finishing details to the packing
of his personal baggage.

The balloon, taken apart for easy transportation, had been sent on
ahead, as had most of their supplies, weapons and other needed
articles. All they would carry with them were handbags, containing
some clothing.

"Then you've