“Let us overtake him,” said Smith, resuming the march. The engineer noted carefully all the deviations of the route, and easily kept a general idea of their direction, which was towards the sea. The party had not descended more than fifty feet further, when their attention was arrested by distant sounds coming from the depths of the rock. They stopped and listened. These sounds, borne along the passage, as the voice through an acoustic tube, were distinctly heard. “Its Top’s barking!” cried Herbert. “Yes, and the brave dog is barking furiously,” added Pencroff. “We have our spears,” said Smith. “Come on, and be ready.” “It is becoming more and more interesting,” whispered Spilett to the sailor, who nodded assent. They hurried to the rescue of the dog. His barks grew more distinct. They could hear that he was in a strange rage. Had he been captured by some animal whom he had disturbed? Without thinking of the danger, the colonists felt themselves drawn on by an irresistible curiosity, and slipped rather than ran down the passage. Sixteen feet lower they came up with the dog. There, the corridor opened out into a vast and magnificent cavern. Top, rushing about, was barking furiously. Pencroff and Neb, shaking their torches, lit up all the inequalities of the granite, and the others, with their spears ready, held themselves prepared for any emergency. But the enormous cavern was empty. The colonists searched everywhere; they could find no living thing. Nevertheless, Top continued barking, and neither threats nor caresses could stop him. “There must be some place where the water escaped to the sea,” said the engineer. “Yes, and look out for a hole,” answered Pencroff. “On, Top, on,” cried Smith, and the dog, encouraged by his master, ran towards the end of the cavern, and redoubled his barking. Following him, they saw by the light of the torches the opening of what looked like a well in the granite. Here, undoubtedly, was the place where the water had found its way out of the cavern, but this time, instead of being a corridor sloping and accessible, it was a perpendicular well, impossible to descend. The torches were waved above the opening. They saw nothing. Smith broke off a burning branch and dropped it into the abyss. The resin, fanned by the wind of its fall, burned brightly and illuminated the interior of the pit, but showed nothing else. Then the flame was extinguished with a slight hiss, which indicated that it had reached the water, which must be the sea level. The engineer calculated, from the time taken in the fall, that the depth was about ninety feet. The floor of the cavern was therefore that distance above the sea. “Here is our house,” said Smith. “But it was preoccupied,” said Spilett, whose curiosity was unsatisfied. “Well, the thing that had it, whether amphibious or not, has fled by this outlet and vacated in our favor,” replied the engineer.