, was an arch, which vomited
a red and flickering light, that faintly shone upon the sea in the track
of the boat. The light was lambent and uncertain, now sinking almost
into insignificance, and now leaping up with a fierceness that caused a
deep glow to throb in the very heart of the mountain. Sometimes a black
figure would pass across this gigantic furnace-mouth, stooping and
rising, as though feeding the fire. One might have imagined that a door
in Vulcan's Smithy had been left inadvertently open, and that the old
hero was forging arms for a demigod.

Blunt turned pale. "It's no mortal," he whispered. "Let's go back."

"And what will Madam say?" returned dare-devil Will Staples who would
have plunged into Mount Erebus had he been paid for it. Thus appealed to
in the name of his ruling passion, Blunt turned his head, and the boat
sped onward.

CHAPTER XXVI. THE WORK OF THE SEA.

The lift of the water-spout had saved John Rex's life. At the moment
when it struck him he was on his hands and knees at the entrance of the
cavern. The wave, gushing upwards, at the same time expanded, laterally,
and this lateral force drove the convict into the mouth of the
subterranean passage. The passage trended downwards, and for some
seconds he was rolled over and over, the rush of water wedging him at
length into a crevice between two enormous stones, which overhung a
still more formidable abyss. Fortunately for the preservation of his
hard-fought-for life, this very fury of incoming water prevented him
from being washed out again with the recoil of the wave. He could hear
the water dashing with frightful echoes far down into the depths beyond
him, but it was evident that the two stones against which he had been
thrust acted as breakwaters to the torrent poured in from the outside,
and repelled the main body of the stream in the fashion he had observed
from his position on the ledge. In a few seconds the cavern was empty.

Painfully extricating himself, and feeling as yet doubtful of his
safety, John Rex essayed to climb the twin-blocks that barred the
unknown depths below him. The first movement he made caused him to
shriek aloud. His left arm--with which he clung to the rope--hung
powerless. Ground against the ragged entrance, it was momentarily
paralysed. For an instant the unfortunate wretch sank despairingly on
the wet and rugged floor of the cave; then a terrible gurgling beneath
his feet warned him of the approac