That it was not a river he was assured as there was no current whatever.

Involuntarily he looked about for light.

There was a faint square far above his head. This he knew must be from the aperture through which he had fallen.

Certainly that must have been a fearful distance to have fallen. To have survived that fall seemed a miracle.

But that light was too far away to be of any service.

All upon the surface of the underground lake was Stygian blackness.

“I don’t know where I am, nor if I shall ever get out of here alive,” muttered the young inventor, ‪“but I must try. I will swim as far as I can.”

And this he proceeded to do.

Striking out he forced his way swiftly through the water.

Pausing to rest, he suddenly heard a startling sound near him.