At intervals, huge geysers of living flame spurted up from the surface to a height of many feet and fell back in a glistening of molten gold and coruscating diamonds.
It was a scene that if it could have been viewed with safety would have drawn tourists in thousands from every corner of the globe.
But to the two spectators the thought that they were looking on one of the marvels of the world brought nothing but desolation and despair.
"This must be the source of the lava flow when the whale's hump is in eruption," said Drew in a toneless voice.
"I suppose so," said Ruth in a voice that for dreariness was a replica of his own. "Do you think it's possible for us to get around it in any way, Allen?"
"Not a chance in the world," answered Drew. "You can see that the passage we followed ends at the brink of the crater. From there on, there's just a wall of solid rock. The only thing left for us to do is to get back to the place where the cave split into three parts."
They retraced their steps with hearts that grew heavier at every step. The passage that had seemed most promising had yielded nothing but bitter disappointment. Only two other chances remained, and who could tell that they led anywhere but to death?
At the juncture of the passageways, they hesitated for a moment only. There was absolutely nothing to indicate that they should take one of the remaining two paths rather than the other. Impenetrable blackness covered both.
"Which shall it be, Ruth?" asked Drew.
"You do the choosing, Allen," Ruth responded.