Half a dozen of them used their combined efforts to roll a rock aside, which revealed a small opening.
Into this they filed, taking our friends with them.
It was dark as pitch inside, but at a word from one of the men a light suddenly appeared.
How it came so quickly our friends were at first at a loss to understand, but in a few seconds it was made plain to them.
As their eyes became accustomed to the ghostly glare the light made, they began looking around them.
They found that the place into which they had been conducted was a cave of about one hundred feet square.
In the center, upon the floor, a man attired in the habiliments of civilization sat, with his arms bound behind him.
A single glance sufficed to show the swamp explorers that it was the man who had left the balloon and started down the stairs in quest of the one with the dog.
He looked up when he saw men of his own appearance approaching, and a smile lit up his countenance.
The five prisoners were at once placed at the side of this man, and then those who had brought them thither immediately left the cave.