ats in a trap, if they hadn't followed us. The underground
city will never be discovered again."

"And now for home!" cried Tom, when they had eaten and drunk
sparingly until they should get back their strength, and had seen to
their slight wounds.

"And our trip wasn't altogether a failure," said Mr. Damon. "We'd
have had more gold if the stone door hadn't trapped us. But I guess
we have enough as it is. I wonder how the Fogers ever found us?"

"They must have followed our trail, though how we'll never know and
they came up to where Delazes and his men were, joined forces with
them, and hunted about until they found the temple," remarked Tom.
"Then they saw the opening, went down, and found the stone door."

"But how did they get it open? and what were they doing with the
head-hunters, and why didn't the head-hunters attack them?" Ned
wanted to know.

"Well, I guess perhaps Delazes knew how to handle those head-hunters,"
replied Tom. "They may be a sort of lost tribe of Mexicans, and
perhaps their ancestors centuries ago owned the city of gold.
At any rate I think some of them knew the secret of raising the
door." And later Tom learned in a roundabout way from the Fogers
that this was so. The father and son had after much hardship joined
forces with Delazes and he, by a promise of the heads of the party
of our friends, and much tobacco, had gained the head-hunters as
allies.

On and on sailed the balloon and our friends regained their strength
after partaking of the nourishing food. They looked at their store
of gold and found it larger than they had thought. Soon they left
far behind them the great plain of the ruined temple, which, had
they but known it was a lake now, for the underground river, perhaps
by some break in the underground mechanism that controlled it, or a
break in the channel, overflowed and covered temple, plain and
underground city with water many fathoms deep.

"Are we going all the way home in the balloon?" asked Ned on the
second day of their voyage in the air, when they had stopped to make
slight repairs.

"No, indeed," replied Tom. "As soon as we get to some city where we
can pack it up, and ship our gold without fear of being robbed, I'm
coming to earth, and go home in a steamer."

This plan was carried out; and a week later, with the gold safely
insured by an express company, and the balloon packed for
transportation, our friends went to a railroad station, and took a
train for Ta