dous organ. To these sounds were added others which seemed to be
peculiar to the cave itself. They appeared to rise from crevices in the
floor, and were no doubt due to the action of those pent-up subterranean
fires which were imprisoned directly, though it may be very far down,
under their feet. Every now and then there came a sudden increase of the
united sounds as if the "swell" of the great organ had been opened, and
such out-gushing was always accompanied with more or less of
indescribable shocks followed by prolonged tremors of the entire
mountain.

If the three friends had been outside to observe what was taking place,
they would have seen that these symptoms were simultaneous with
occasional and extremely violent outbursts from the crater of
Perboewatan and his compeers. Indeed they guessed as much, and two of
them at least were not a little thankful that, awesome as their position
was, they had the thick mountain between them and the fiery showers
outside.

Of all this the hermit took no notice, but, hastening into the inner
cavern, opened a small box, and took therefrom a bundle of papers and a
little object which, at a first glance, Nigel supposed to be a book, but
which turned out to be a photograph case. These the hermit put carefully
into the breastpocket of his coat and then turned to his companions with
a sigh as if of relief.

"I think there is no danger of anything occurring at this part of the
island," he remarked, looking round the cave, "for there is no sign of
smoke and no sulphurous smell issuing from any of the crevices in walls
or floor. This, I think, shows that there is no direct communication
with Rakata and the active volcano--at least not at present."

"Do you then think there is a possibility of an outbreak at some future
period?" asked Nigel.

"Who can tell? People here, who don't study the nature of volcanoes
much, though surrounded by them, will expect things ere long to resume
their normal condition. I can never forget the fact that the greater
part of Krakatoa stands, as you know, exactly above the spot where the
two great lines of volcanic action cross, and right over the mouth of
the immense crater to which Perboewatan and all the other craters serve
as mere chimneys or safety-valves. We cannot tell whether a great
eruption similar to that of 1680 may not be in store for us. The only
reason that I can see for the quiescence of this peak of Rakata is, as I
said to you once befo