The internal fires raging there, no doubt, caused the tremulous motion. Indeed, the atmosphere was charged with waves of heat, which was evidence enough in itself of that.
Entering the hollow mountain, the four mail-clad men skirted the lake of molten lava.
The heat from this was something not exactly pleasant to bear. They did not venture too near the edge.
Upon every hand was visible evidences of the great struggle of the volcanic elements in ages past.
It was a wonderful sight, and Professor Gaston made the best of it. He declared:
“I am the most fortunate man in America to-day to be enabled to be here. This is a wonderful experience!”
As the professor had not a suit of armor on it was decided that he should remain in the outer cavern where he would be very much safer.
He was anxious to search for specimens, and at the same time was not desirous of an encounter with the natives.
Leaving Professor Gaston in the outer cavern, Frank Reade, Jr., and his three companions boldly entered the subterranean passage which led presumably to the stronghold of the Antarctic natives.
To their surprise the passage was hardly a hundred feet in length.