idol of solid gold, weighing many pounds, and,
in consequence, of great value."

"Of solid gold you say?" asked Ned eagerly.

"That's it.  Got on your banking air already,"
Tom laughed.  "To sum it up for you--notice
I use the word `sum,' which is very appropriate
for a bank--the professor has got on the track
of another lost or hidden city.  This one, the
name of which doesn't appear, is in the Copan
valley of Honduras, and----"

"Copan," interrupted Ned.  "It sounds like
the name of some new floor varnish."

"Well, it isn't, though it might be," laughed
Tom.  "Copan is a city, in the Department of
Copan, near the boundary between Honduras and
Guatemala.  A fact I learned from the article
and not because I remembered my geography."

"I was going to say," remarked Ned with a
smile, "that you were coming it rather strong
on the school-book stuff."

"Oh, it's all plainly written down there," and
Tom waved toward the magazine at which Ned
was looking.  "As you'll see, if you take the
trouble to go through it, as I did, Copan is, or
maybe was, for all I know, one of the most
important centers of the Mayan civilization."

"What's Mayan?" asked Ned.  "You see I'm
going to imbibe my information by the deductive
rather than the excavative process," he added
with a laugh.

"I see," laughed Tom.  "Well, Mayan refers
to the Mayas, an aboriginal people of Yucatan.
The Mayas had a peculiar civilization of their
own, thousands of years ago, and their calendar
system was so involved----"

"Never mind about dates," again interrupted
Ned.  "Get down to brass tacks.  I'm willing
to take your word for it that there's a Copan
valley in Honduras.  But what has your friend
Professor Bumper to do with it?"

"This.  He has come across some old
manuscripts, or ancient document records, referring
to this valley, and they state, according to this
article he has written for the magazine, that
somewhere in the valley is a wonderful city,
traces of which have been found twenty to forty
feet below the surface, on which great trees are
growing, showing that the city was covered
hundreds, if not thousands, of years ago."

"But where does the idol of gold come in?"

"I'm coming to that," said Tom.  "Though,
if Professor Bumper has his way, the idol will
be coming out instead of coming in."

"You mean he wants to get it and take it
away from the Copan valley, Tom?"

"That's it, Ned.  It has great value not only
from the amount of pure gold that is in it, but
as an antique.  I fancy the professor is more
interested in that aspect of it.  But he's written
a wonderful story, telling how he happened to
come across the ancient manuscripts in the tomb
of some old Indian whose mummy he unearthed
on a trip to Central America.

"Then he tells of the trouble he had in
discovering how to solve the key to the translation
code; but when he did, he found a great story
unfolded to him.

"This story has to do with the hidden city,
and tells of the ancient civilization of those who
lived in the Copan valley thousands of years ago.
The people held this idol of gold to be their
greatest treasure, and they put to death many of
other tribes who sought to steal it."

"Whew!" whistled Ned.  "That IS some yarn.
But what is Professor Bumper going to do about it?"

"I don't know.  The article seems to be written
with an idea of interesting scientists and
research societies, so that they will raise money
to conduct a searching expedition.

"Perhaps by this time the party may be
organized--this magazine is several months old.
I have been so busy on my stabilizer patent that
I haven't kept up with current literature.  Take
it home and read it! Ned.  That is if you're
through telling me about my affairs," for Ned,
who had formerly worked in the Shopton bank,
had recently been made general financial man-
ager of the interests of Tom and his father.  The
two were inventors and proverbially poor business
men, though they had amassed a fortune.

"Your financial affairs are all right, Tom," said
Ned.  "I have just been going over the books,
and I'll submit a detailed report later."

The telephone bell rang and Tom picked up
the instrument from the desk.  As he answered in
the usual way and then listened a moment, a
strange look came over his face.

"Well, this certainly is wonderful!" he exclaimed,
in much the same manner as when he had finished
reading the article about the idol.  "It certainly
is a strange coincidence," he added,
speaking in an aside to Ned while he himself
still listened to what was being told to him
over the telephone wire.

CHAPTER II

PROFESSOR BUMPER ARRIVES

"What's the matter, Tom?  What is it?"
asked Ned Newton, attracted by the strange
manner of his chum at the telephone.  "Has
anything happened?"

But the young inventor was too busy listening
to the unseen speaker to answer his chum,
even if he heard what Ned remarked, which is
doubtful.

"Well, I might as well wait until he is
through," mused Ned, as he started to leave the
room.  Then as Tom motioned to him to remain,
he murmured: "He may have something
to say to me later.  But I wonder who is talking
to him."

There was no way of finding out, however,
until Tom had a chance to talk to Ned, and at
present the young scientist was eagerly listening
to what came over the wire.  Occasionally Ned
could hear him say:

"You don't tell me! That is surprising! Yes
--yes! Of course if it's true it means a big
thing, I can understand that.  What's that?  No,
I couldn't make a promise like that.  I'm sorry,
but----"

Then the person at the other end of the wire
must have plunged into something very interesting
and absorbing, for Tom did not again
interrupt by interjected remarks.

Tom.  Swift, as has been said, was an inventor,
as was his father.  Mr. Swift was now rather old
and feeble, taking only a nominal part in the
activities of the firm made up of himself and his
son.  But his inventions were still used, many
of them being vital to the business and trade of
this country.

Tom and his father lived in the village of
Shopton, New York, and their factories covered
many acres of ground.  Those who wish to read
of the earliest activities of Tom in the inventive
line are referred to the initial volume, "Tom
Swift and His Motor Cycle."  From then on he
and his father had many and exciting adventures.
In a motor boat, an airship, and a submarine
respectively the young inventor had gone through
many perils.  On some of the trips his chum,
Ned Newton, accompanied him, and very often
in the party was a Mr. Wakefield Damon, who
had a curious habit of "blessing" everything
that happened to strike his fancy.

Besides Tom and his father, the Swift household
was made up of Eradicate Sampson, a colored
man-of-all-work, who, with his mule Boomerang,
did what he could to keep the grounds
around the house in order.  There was also Mrs.
Baggert, the housekeeper, Tom's mother being
dead.  Mr. Damon, living in a neighboring town,
was a frequent visitor in the Swift home.

Mary Nestor, a girl of Shopton, might also
be mentioned.  She and Tom were more than
just good friends.  Tom had an idea that some