hinery, and without machinery there would be no railways, no
steamers, no manufactories, nothing of that which is indispensable to
modern civilization!"

"But what will they find?" asked Pencroft. "Can you guess, captain?"

"Nearly, my friend."

"And what will they burn instead of coal?"

"Water," replied Harding.

"Water!" cried Pencroft, "water as fuel for steamers and engines! water
to heat water!"

"Yes, but water decomposed into its primitive elements," replied Cyrus
Harding, "and decomposed doubtless, by electricity, which will then have
become a powerful and manageable force, for all great discoveries, by
some inexplicable laws, appear to agree and become complete at the same
time. Yes, my friends, I believe that water will one day be employed
as fuel, that hydrogen and oxygen which constitute it, used singly or
together, will furnish an inexhaustible source of heat and light, of
an intensity of which coal is not capable. Some day the coalrooms of
steamers and the tenders of locomotives will, instead of coal, be stored
with these two condensed gases, which will burn in the furnaces with
enormous calorific power. There is, therefore, nothing to fear. As long
as the earth is inhabited it will supply the wants of its inhabitants,
and there will be no want of either light or heat as long as the
productions of the vegetable, mineral or animal kingdoms do not fail us.
I believe, then, that when the deposits of coal are exhausted we shall
heat and warm ourselves with water. Water will be the coal of the
future."

"I should like to see that," observed the sailor.

"You were born too soon, Pencroft," returned Neb, who only took part in
the discussion by these words.

However, it was not Neb's speech which interrupted the conversation, but
Top's barking, which broke out again with that strange intonation which
had before perplexed the engineer. At the same time Top began to run
round the mouth of the well, which opened at the extremity of the
interior passage.

"What can Top be barking in that way for?" asked Pencroft.

"And Jup be growling like that?" added Herbert.

In fact the orang, joining the dog, gave unequivocal signs of agitation,
and, singular to say, the two animals appeared more uneasy than angry.

"It is evident," said Gideon Spilett, "that this well is in direct
communication with the sea, and that some marine animal comes from time
to time to breathe at the bottom."

"That's evident," repli