Suddenly, as a bomb from a shell, a huge stone was flung hundreds of yards up from the jaws of the crater, and falling with a mighty crash upon the rock below, split into ten thousand fragments, which bounded down the sides of the mountain, sparkling and groaning as they went.

One of these, the largest fragment, struck the narrow space of soil between the Englishman and the guide, not three feet from the spot where the former stood.

Merton uttered an exclamation of terror, and Glyndon held his breath and shuddered.
"Diavolo!" cried the guide; "descend, Excellencies, descend! We have not a moment to lose; follow me close." So saying, the guide and the peasant fled with as much swiftness as they were able to bring to bear.

Merton, ever more prompt and ready than his friend, imitated their example; and Glyndon, more confused than alarmed, followed close.

But they had not gone many yards before, with a rushing and sudden blast, came from the crater an enormous volume of vapor.