.

And there they stood in a noise that was now deafening, holding their
lights on high, and trying to pierce the black darkness in front, but of
course in vain.

A peculiar fact struck Oliver now, as he stood pretty close to the lava
edge of the angular platform upon which they had halted, and this was,
that the flames of all their candles were drawn away from them toward
where the water of the conjoined streams must be falling in one plunge
down into some terrible gulf. He knew at once that this was caused by a
strong, steady current of air setting towards the falls, and in his
uneasiness he was about to point out to Panton that their candles were
rapidly burning away, when the latter suddenly lit his remaining piece
of magnesium wire, and the next minute they were all straining their
eyes, and now looking into a misty glare of light, right in front--
evidently the mist rising from the churned-up water--or now upon their
grotesque black shadows, cast by the white-smoked magnesium upon the
floor and the ceiling far above.

But there was no sign of the water itself, only the conformation of the
lava stream whose edge could be seen upon the other side of the second
river at least thirty feet away.

"What's to be done?" said Panton at last, as the magnesium burned out
and all was once more black darkness.

"Get back," said Oliver, with his lips to his friend's ear. "The
candles are guttering away terribly, and we must not be left in the
dark."

"No," yelled Panton, "that wouldn't be pleasant. Hang it, all my
candle's done."

Time had gone faster than they had expected since the second candles
were lit, and turning to Oliver he said, sharply,--

"There, you lead the way back. It isn't far if you step out. Forward!"

Oliver wanted no telling, and he started back, but did not begin to
breathe freely till the angle of the rock wall was passed and they found
themselves again in silence, just too as another candle began to
flicker.

"Hullo!" cried Oliver, glancing back. "What does this mean?"

"What?" said Panton.

"The number of lights. Yours is gone and this one will be out directly,
but there ought to be three more. Drew, Smith, ourselves. Here, where
is Wriggs?"

There was no answer, and in a strained, excited voice, Smith shouted,--

"Hi, Billy lad, where are yer?"

There was a whispering echo, but nothing more till Oliver spoke,--

"Where did you see him last?"

"See him, sir, why yonder, w