“But if an eruption of Mount Franklin occurred,” asked Spilett, “would there not be some danger to Lincoln Island?”

“I do not think so,” answered the reporter.  “The crater, that is to say, the safety-valve, exists, and the overflow of smoke and lava, would escape, as it did formerly, by this customary outlet.”

“Unless the lava opened a new way for itself towards the fertile parts of the island!”

“And why, my dear Spilett,” answered Cyrus Harding, “should it not follow the road naturally traced out for it?”

“Well, volcanoes are capricious,” returned the reporter.

“Notice,” answered the engineer, “that the inclination of Mount Franklin favors the flow of water towards the valleys which we are exploring just now.  To turn aside this flow, an earthquake would be necessary to change the mountain’s center of gravity.”

“But an earthquake is always to be feared at these times,” observed Gideon Spilett.

“Always,” replied the engineer, “especially when the subterranean forces begin to awake, as they risk meeting with some obstruction, after a long rest.  Thus, my dear Spilett, an eruption would be a serious thing for us, and it would be better that the volcano should not have the slightest desire to wake up.  But we could not prevent it, could we?  At any rate, even if it should occur, I do not think Prospect Heights would he seriously threatened.  Between them and the mountain, the ground is considerably depressed, and if the lava should ever take a course towards the lake, it would be cast on the downs and the neighboring parts of Shark Gulf.”

“We have not yet seen any smoke at the top of the mountain, to indicate an approaching eruption,” said Gideon Spilett.

“No,” answered Harding, “not a vapor escapes from the crater, for it was only yesterday that I attentively surveyed the summit.  But it is probable that at the lower part of the chimney, time may have accumulated rocks, cinders, hardened lava, and that this valve of which I spoke, may at any time become overcharged.  But at the first serious effort, every obstacle will disappear, and you may be certain, my dear Spilett, that neither the island, which is the boiler, nor the volcano, which is the chimney, will burst under the pressure of gas.  Nevertheless, I repeat, it would be better that there should not be an eruption.”

“And yet we are not mistaken,” remarked the reporter.  “Mutterings can be distinctly heard in the very bowels of the volcano!”

“You are right,” said the engineer, again listening attentively.  “There can be no doubt of it.  A commotion is going on there, of which we can neither estimate the importance nor the ultimate result.”

Cyrus Harding and Spilett, on coming out, rejoined their companions, to whom they made known the state of affairs.

“Very well!” cried Pencroft, “The volcano wants to play his pranks!  Let him try, if he likes!  He will find his master!”