fish lizards from the
lake. This huge sack had been sewn up at one end and only a small
orifice left at the other. Into this opening several bamboo canes had
been inserted and the other ends of these canes were in contact with
conical clay funnels which collected the gas bubbling up through the
mud of the geyser. Soon the flaccid organ began to slowly expand and
show such a tendency to upward movements that Challenger fastened the
cords which held it to the trunks of the surrounding trees. In half an
hour a good-sized gas-bag had been formed, and the jerking and
straining upon the thongs showed that it was capable of considerable
lift. Challenger, like a glad father in the presence of his
first-born, stood smiling and stroking his beard, in silent,
self-satisfied content as he gazed at the creation of his brain. It
was Summerlee who first broke the silence.

"You don't mean us to go up in that thing, Challenger?" said he, in an
acid voice.

"I mean, my dear Summerlee, to give you such a demonstration of its
powers that after seeing it you will, I am sure, have no hesitation in
trusting yourself to it."

"You can put it right out of your head now, at once," said Summerlee
with decision, "nothing on earth would induce me to commit such a
folly. Lord John, I trust that you will not countenance such madness?"

"Dooced ingenious, I call it," said our peer. "I'd like to see how it
works."

"So you shall," said Challenger. "For some days I have exerted my
whole brain force upon the problem of how we shall descend from these
cliffs. We have satisfied ourselves that we cannot climb down and that
there is no tunnel. We are also unable to construct any kind of bridge
which may take us back to the pinnacle from which we came. How then
shall I find a means to convey us? Some little time ago I had remarked
to our young friend here that free hydrogen was evolved from the
geyser. The idea of a balloon naturally followed. I was, I will
admit, somewhat baffled by the difficulty of discovering an envelope to
contain the gas, but the contemplation of the immense entrails of these
reptiles supplied me with a solution to the problem. Behold the
result!"

He put one hand in the front of his ragged jacket and pointed proudly
with the other.

By this time the gas-bag had swollen to a goodly rotundity and was
jerking strongly upon its lashings.

"Midsummer madness!" snorted Summerlee.

Lord John was delighted with t