“Well, then, I saw that these fissures widen under the internal pressure from within, that the wall of basalt is gradually giving way, and that after a longer or shorter period it will afford a passage to the waters of the lake which fill the cavern.”
“Good!” replied Pencroft, with an attempt at pleasantry. “The sea will extinguish the volcano, and there will be an end of the matter!”
“Not so!” said Cyrus Harding, “should a day arrive when the sea, rushing through the wall of the cavern, penetrates by the central shaft into the interior of the island to the boiling lava, Lincoln Island will that day be blown into the air—just as would happen to the island of Sicily were the Mediterranean to precipitate itself into Mount Etna.”
The colonists made no answer to these significant words of the engineer. They now understood the danger by which they were menaced.
It may be added that Cyrus Harding had in no way exaggerated the danger to be apprehended. Many persons have formed an idea that it would be possible to extinguish volcanoes, which are almost always situated on the shores of a sea or lake, by opening a passage for the admission of the water. But they are not aware that this would be to incur the risk of blowing up a portion of the globe, like a boiler whose steam is suddenly expanded by intense heat. The water, rushing into a cavity whose temperature might be estimated at thousands of degrees, would be converted into steam with a sudden energy which no enclosure could resist.
It was not therefore doubtful that the island, menaced by a frightful and approaching convulsion, would endure only so long as the wall of Dakkar Grotto itself should endure. It was not even a question of months, nor of weeks; but of days, it might be of hours.
The first sentiment which the colonists felt was that of profound sorrow. They thought not so much of the peril which menaced themselves personally, but of the destruction of the island which had sheltered them, which they had cultivated, which they loved so well, and had hoped to render so flourishing. So much effort ineffectually expended, so much labour lost.
Pencroft could not prevent a large tear from rolling down his cheek, nor did he attempt to conceal it.
Some further conversation now took place. The chances yet in favour of the colonists were discussed; but finally it was agreed that there was not an hour to be lost, that the building and fitting of the vessel should be pushed forward with their utmost energy, and that this was the sole chance of safety for the inhabitants of Lincoln Island.
All hands, therefore, set to work on the vessel. What could it now avail to sow, to reap, to hunt, to increase the stores of Granite House? The contents of the store-house and outbuildings contained more than sufficient to provide the ship for a voyage, however long might be its duration. But it was imperative that the ship should be ready to receive them before the inevitable catastrophe should arrive.