"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 law, 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 coal-rooms 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.