It was by this that the water escaped; and this time it was not an oblique and practicable passage, but a perpendicular well, into which it was impossible to venture.
The torches were held over the opening: nothing could be seen.

Harding took a lighted branch, and threw it into the abyss.

The blazing resin, whose illuminating power increased still more by the rapidity of its fall, lighted up the interior of the well, but yet nothing appeared.

The flame then went out with a slight hiss, which showed that it had reached the water, that is to say, the level of the sea.
The engineer, calculating the time employed in its fall, was able to calculate the depth of the well, which was found to be about ninety feet.
The floor of the cavern must thus be situated ninety feet above the level of the sea.
"Here is our dwelling," said Cyrus Harding.
"But it was occupied by some creature," replied Gideon Spilett, whose curiosity was not yet satisfied.
"Well, the creature, amphibious or otherwise, has made off through this opening," replied the engineer, "and has left the place for us." "Never mind," added the sailor, "I should like very much to be Top just for a quarter of an hour, for he doesn't bark for nothing!" Cyrus Harding looked at his dog, and those of his companions who were near him might have heard him murmur these words,-- "Yes, I believe that Top knows more than we do about a great many things." However, the wishes of the settlers were for the most part satisfied.
Chance, aided by the marvelous sagacity of their leader, had done them great service.

They had now at their disposal a vast cavern, the size of which could not be properly calculated by the feeble light of their torches, but it would certainly be easy to divide it into rooms, by means of brick partitions, or to use it, if not as a house, at least as a spacious apartment.