“It’s something like the ancient Greek or Persian language,” declared Mr. Damon, who was quite a scholar.  “I can make out a word here and there, and it seems to be a warning against disturbing the statue, or damaging it.  Probably it was put there to warn small boys thousands of years ago, if they ever allowed small boys in this place.”

“Does it say what will be done to whoever harms the statue?” asked Tom with a laugh.

“Probably it does, but I can’t make out what it is,” answered Mr. Damon.

“Then here goes to see if we can’t overturn it and hack off the head,” went on Tom.  “I’ve got a sharp little hatchet, and gold is very soft to cut.  Over she goes.”

“You never can upset that statue,” declared Ned.

“Yes, I can,” cried the young inventor.  “I brought a long, thin, but very strong rope with me, and I think if we all pull together we can do it.”

Tom made a noose and skillfully threw it over the head of the statue.  It settled about the neck, and then, all taking hold, and walking away a short distance, they gave a “long pull, a strong pull, and a pull altogether.”

At first the statue would not move, but when they strained on the rope, the image suddenly tilted, and, a moment later it tumbled to the stone pavement.  But the fall was not as heavy as should have resulted from a statue of solid metal.  There was a tinkling sound.

“That’s queer!” cried Tom.  “It didn’t make half the fuss I expected,” and he hurried up to look at the fallen statue.  “Why!” he cried in astonishment, “it’s hollow—­the big golden statue is hollow—­it’s a fake!”

And so it was.  The big image was only a shell of gold.

“Not so valuable as it looked,” commented Ned.  “We could take that with us in the balloon, if it wasn’t so big.”

“Well, here goes for the head, anyhow!” exclaimed Tom, and with a few blows of his keen little axe he severed the neck.  As he held it up for all to see—­rather a grewsome sight it was, too, in the flickering light of the gas torches—­there sounded throughout the underground city, a dull, booming noise, like distant thunder.

“What’s that?” cried Ned.

“Bless my bath sponge!” exclaimed Mr. Damon, “I hope the water isn’t rising in the river.”

“Oh land a massy!” gasped Eradicate.

Without a word Tom dropped the golden head and made for the street that led to the tunnel.  The others followed, and soon caught up to the young inventor.  On and on they ran, with only the light of their electric flash torches to guide them.  Suddenly Tom stopped.

“Go on!” cried Ned.  “See what’s happened!  Go on!”

“I can’t,” answered Tom, and they all wondered at his voice.  “There’s a big block of stone across the tunnel, and I can’t go another step.  The stone gate has fallen.  We’re trapped here in the underground city of gold!”

“Bless my soul!  The tunnel closed?” cried Mr. Damon.