So saying, the guide and the peasant fled with as much swiftness as they were able to bring to bear.  Mervale, 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 vapour.  It pursued,—­it overtook, it overspread them.  It swept the light from the heavens.  All was abrupt and utter darkness; and through the gloom was heard the shout of the guide, already distant, and lost in an instant amidst the sound of the rushing gust and the groans of the earth beneath.  Glyndon paused.  He was separated from his friend, from the guide.  He was alone,—­with the Darkness and the Terror.  The vapour rolled sullenly away; the form of the plumed fire was again dimly visible, and its struggling and perturbed reflection again shed a glow over the horrors of the path.  Glyndon recovered himself, and sped onward.  Below, he heard the voice of Mervale calling on him, though he no longer saw his form.  The sound served as a guide.  Dizzy and breathless, he bounded forward; when—­hark!—­a sullen, slow rolling sounded in his ear!  He halted,—­and turned back to gaze.  The fire had overflowed its course; it had opened itself a channel amidst the furrows of the mountain.  The stream pursued him fast—­fast; and the hot breath of the chasing and preternatural foe came closer and closer upon his cheek!  He turned aside; he climbed desperately with hands and feet upon a crag that, to the right, broke the scathed and blasted level of the soil.  The stream rolled beside and beneath him, and then taking a sudden wind round the spot on which he stood, interposed its liquid fire,—­a broad and impassable barrier between his resting-place and escape.  There he stood, cut off from descent, and with no alternative but to retrace his steps towards the crater, and thence seek, without guide or clew, some other pathway.

For a moment his courage left him; he cried in despair, and in that overstrained pitch of voice which is never heard afar off, to the guide, to Mervale, to return to aid him.

No answer came; and the Englishman, thus abandoned solely to his own resources, felt his spirit and energy rise against the danger.  He turned back, and ventured as far towards the crater as the noxious exhalation would permit; then, gazing below, carefully and deliberately he chalked out for himself a path by which he trusted to shun the direction the fire-stream had taken, and trod firmly and quickly over the crumbling and heated strata.