"A good omen! I'm sure the city of gold must be near here, and in the morning we'll begin our search for the secret tunnel that leads to it."
"That's the stuff!" cried Ned enthusiastically.
An instant later it seemed to get dark very suddenly, as it does in the tropics, and almost with the first shadows of night there came a strange sound from the ruined temple.
It was a low moaning, rumbling sound, like a mighty wind, afar off, and it sent a cold shiver down the spines of all in the little party.
"Good land a' massy! What am dat?" moaned Eradicate, as he darted back toward the balloon.
"Bless my looking glass!" cried Mr. Damon.
A second later the noise suddenly increased, and something black, accompanied by a noise of rapidly beating wings rushed from one of the immense doorways.
"Bats!" cried Tom. "Thousands of bats! I'm glad we didn't go in after dark!" And bats they were, that had made the noise as they rushed out on their nightly flight.
"Ugh!" shuddered Mr. Damon. "I detest the creatures! Let's get under cover."
"Yes," agreed Tom, "we'll have supper, turn in, and be up early to look for the tunnel. We're here at last. I'll dream of gold to-night."
Eradicate soon had a meal in preparation,
