When it dropped, while he was on the black island, he soon began to feel the effect of the gases rising imperceptibly from the soil, and had he not had the good fortune to escape so soon, no doubt he would have fallen a victim.

He could not congratulate himself sufficiently upon his good fortune.

The other circumstances appeared to be due to the decay of the ancient city, to the decomposition of accumulated matter, to phosphorescence and gaseous exhalations.

The black rocks that crumbled at a touch were doubtless the remains of ancient buildings saturated with the dark water and vapours.

Inland similar remains were white, and resembled salt.
But the great explosions which occurred as he was leaving, and which sent heavy rollers after him, were not easily understood, till he remembered that in Sylvester's "Book of Natural Things" it was related that "the ancient city had been undermined with vast conduits, sewers, and tunnels, and that these communicated with the sea".