f solid gold, as large as three men, and there is some
queer mystery about it, so that white traveler said. A mystery he
wanted to solve but could not."

"So, dad, I'm going to search for that underground city, not only
for the mere gold, but to see if I can solve the mystery of the big
gold statue. And if I could bring it away," cried Tom in great
excitement as he waved the missionary's letter above his head, "it
would be one of the wonders of the world--dad, for, not only is it
very valuable, but it is most beautifully carved."

"Well, I might as well give up my gyroscope work until you come back
from the city of gold, Tom, I can see that," said Mr. Swift, with a
faint smile. "And if you go, I hope you come back. I don't want that
mysterious image to be the undoing of you."

"Oh, I'll come back all right!" cried Tom confidently. "Ho! for the
city of gold and the images thereof! I'm going to get ready to
start!"

"And so am I!" cried Mr. Damon. "Bless my shoe strings, Tom, but I'm
with you! I certainly am!" and the little man excitedly shook hands
with Tom Swift, while the aged inventor looked on and nodded his
head doubtfully. But Tom was full of hope.

CHAPTER II

AN UNSUSPECTED LISTENER

For a few moments after Tom Swift had announced his decision to
start for the city of gold, and Mr. Damon had said he would
accompany the young inventor, there was a silence in the workshop.
Then Mr. Swift laid aside the delicate mechanism of the new model
gyroscope on which he had been working, came over to his son, and
said:

"Well, Tom, if you're going, that means you're going--I know enough
to predict that. I rather wish you weren't, for I'm afraid no good
will come of this."

"Now, dad, don't be talking that way!" cried Tom gaily. "Pack up and
come along with us." Lovingly he placed his arm around the bent
shoulders of his father.

"No, Tom, I'm too old. Home is the place for me."

"Bless my arithmetic tables!" exclaimed Mr. Damon, "you're not so
much older than I am, and I'm going with Tom. Come on, Mr. Swift."

"No, I can't put up with dangers, hardship and excitement as I used
to. I'd better stay home. Besides, I want to perfect my new
gyroscope. I'll work on that while you and Tom are searching for the
city of gold. But, Tom, if you're going you'd better have something
more definite to look for than an unknown city, located on a map
drawn by some African bushman."

"I intend to, dad. I guess when