Now it opened gently, now shut again.

Again it glimmered and gradually expanded until the whole cavern became aglow with light, and presented a scene of such enchanting beauty that all on board were spell-bound with admiration.

Massive columns, grand and impressive, rose on every side to the very roof, and reflected all the colors of the rainbow.

And through them the gallant old ship continued to sail, like a phantom.
This bright, bewitching scene continued for about fifteen minutes, when the light gradually died away, and all became dark and solemn.

Then deep, plunging sounds of falling water indicated with startling effect that the ship was approaching a mighty cataract, down which she must soon plunge to her destruction.