Mark Woolston now comprehended his situation, notwithstanding the intense darkness which prevailed, except in those brief intervals of lurid light.  He had felt the shock of an earthquake, and the volcano had suddenly become active.  Smoke and ashes certainly filled the air, and our poor hermit instinctively looked towards his crater, already so verdant and lively, in the expectation of seeing it vomit flames.  Everything there was tranquil; the danger, if danger there was, was assuredly more remote.  But the murky vapour which rendered breathing exceedingly difficult, also obstructed the view, and prevented his seeing where the explosion really was.  For a brief space our young man fancied he must certainly be suffocated; but a shift of wind came, and blew away the oppressive vapour, clearing the atmosphere of its sulphurous and most offensive gases and odours.  Never did feverish tongue enjoy the cooling and healthful draught, more than Mark rejoiced in this change.  The wind had got back to its old quarter, and the air he respired soon became pure and refreshing.  Had the impure atmosphere lasted ten minutes longer, Mark felt persuaded he could not have breathed it with any safety.

The light was now most impatiently expected by our young man.  The minutes seemed to drag; but, at length, the usual signs of returning day became apparent to him, and he got on the bowsprit of the ship, as if to meet it in its approach.  There he stood looking to the eastward, eager to have ray after ray shoot into the firmament, when he was suddenly struck with a change in that quarter of the ocean, which at once proclaimed the power of the effort which the earth had made in its subterranean throes.  Naked rocks appeared in places where Mark was certain water in abundance had existed a few hours before.  The sea-wall, directly ahead of the ship, and which never showed itself above the surface more than two or three inches, in any part of it, and that only at exceedingly neap tides, was now not only bare for a long distance, but parts rose ten and fifteen feet above the surrounding sea.  This proved, at once, that the earthquake had thrust upward a vast surface of the reef, completely altering the whole appearance of the shoal!  In a word, nature had made another effort, and islands had been created, as it might be in the twinkling of an eye.

Mark was no sooner assured of this stupendous fact, than he hurried on to the poop, in order to ascertain what changes had occurred in and about the crater.  It had been pushed upward, in common with all the rocks for miles on every side of it, though without disturbing its surface!  By the computation of our young man, the Reef, which previously lay about six feet above the level of the ocean, was now fully twenty, so many cubits having been, by one single but mighty effort of nature, added to its stature.  The planks which led from the stern of the vessel to the shore, and which had formed a descent, were now nearly level, so much water having left the basin as to produce this change.  Still the ship floated, enough remaining to keep her keel clear of the bottom.