hes. It was just half-past one. They sent a
last long look at the sky and the surrounding heights. As they did so
there rolled forth upon the heavy air a long, low boom of distant
thunder. Then they fell into their places and entered the cavern, the
same unspoken thought in each man's mind--Would they ever behold the
fair light of day again?

And the distant, muttering thunder peal, hoarse, heavy, sullen, breaking
upon the sultry air, at the moment when they left the outer world,
struck them as an omen--the menacing voice of outraged Nature booming
the knell of those who had the temerity to seek to penetrate her
innermost mysteries.

CHAPTER FORTY FOUR.

INFERNO.

For the first forty yards the roof of the cave was so low that they had
to advance in a stooping posture. Then it heightened and the tunnel
widened out simultaneously. Eustace led the way, his bull's-eye lantern
strapped around him, throwing a wide disk of yellow light in front.
Behind him, but keeping a hand on his shoulder in order to guide him,
walked Josane; the other two following in single file.

A turn of the way had shut out the light from the entrance. Eustace
closing the slide of the lantern for a moment, they were in black,
pitchy darkness.

A perceptible current of air blew into the cavern. That looked as if
there should be an outlet somewhere. Old Josane, while enjoining
silence upon the rest of the party, had, from the moment they had
entered, struck up a low, weird, crooning song, which sounded like an
incantation. Soon a glimmer of light showed just in front.

"That is the other way in," muttered old Josane. "That is the way I
came in. The other is the way I came out. _Hau_!"

An opening now became apparent--a steep, rock shaft, reaching away into
the outer air. It seemed to take one or more turnings in its upward
passage, for the sky was not visible, and the light only travelled down
in a dim, chastened glimmer as though it was intercepted in its course.
An examination of this extraordinary feature revealed the fact that it
was a kind of natural staircase.

"This is the way I came in. Ha!" muttered Josane again, with a glare of
resentment in his eyes as though recalling to mind some particularly
ignominious treatment--as he narrowly scrutinised the slippery, rocky
sides of the shaft.

"I suppose it'll be the best way for us to get out," said Hoste.
"Anything rather than that devil of a scramble again."

"The t