Then the tones of the organ were heard, and, preceded by the minister, the group advanced into the chapel. The Divine blessing was first invoked on all present. Then Harry and Nell remained alone before the minister, who, holding the sacred book in his hand, proceeded to say, "Harry, will you take Nell to be your wife, and will you promise to love her always?"

"I promise," answered the young man in a firm and steady voice.

"And you, Nell," continued the minister, "will you take Harry to be your husband, and--"

Before he could finish the sentence, a prodigious noise resounded from without. One of the enormous rocks, on which was formed the terrace overhanging the banks of Loch Malcolm, had suddenly given way and opened without explosion, disclosing a profound abyss, into which the waters were now wildly plunging.

In another instant, among the shattered rocks and rushing waves appeared a canoe, which a vigorous arm propelled along the surface of the lake. In the canoe was seen the figure of an old man standing upright. He was clothed in a dark mantle, his hair was dishevelled, a long white beard fell over his breast, and in his hand he bore a lighted Davy safety lamp, the flame being protected by the metallic gauze of the apparatus.

In a loud voice this old man shouted, "The fire-damp is upon you! Woe--woe betide ye all!"

At the same moment the slight smell peculiar to carburetted hydrogen was perceptibly diffused through the atmosphere. And, in truth, the fall of the rock had made a passage of escape for an enormous quantity of explosive gas, accumulated in vast cavities, the openings to which had hitherto been blocked up.

Jets and streams of the fire-damp now rose upward in the vaulted dome; and well did that fierce old man know that the consequence of what he had done would be to render explosive the whole atmosphere of the mine.

James Starr and several others, having hastily quitted the chapel, and perceived the imminence of the danger, now rushed back, crying out in accents of the utmost alarm, "Fly from the mine! Fly instantly from the mine!"

"Now for the fire-damp! Here comes the fire-damp!" yelled the old man, urging his canoe further along the lake.

Harry with his bride, his father and his mother, left the chapel in haste and in terror.

"Fly! fly for your lives!" repeated James Starr. Alas! it was too late to fly! Old Silfax stood there, prepared to fulfill his last dreadful threat--prepared to stop the marriage of Nell and Harry by overwhelming the entire population of the place beneath the ruins of the coal mine.

As he stood ready to accomplish this act of vengeance, his enormous owl, whose white plumage was marked with black spots, was seen hovering directly above his head.

At that moment a man flung himself into the waters of the lake, and swam vigorously towards the canoe.

It was Jack Ryan, fully determined to reach the madman before he could do the dreadful deed of destruction.

Silfax saw him coming. Instantly he smashed the glass of his lamp, and, snatching out the burning wick, waved it in the air.

Silence like death fell upon the astounded multitude. James Starr, in the calmness of despair, marvelled that the inevitable explosion was even for a moment delayed.

Silfax, gazing upwards with wild and contracted features, appeared to become aware that the gas, lighter than the lower atmosphere, was accumulating far up under the dome; and at a sign from him the owl, seizing in its claw the lighted match, soared upwards to the vaulted roof, towards which the madman pointed with outstretched arm.

Another second and New Aberfoyle would be no more.

Suddenly Nell sprang from Harry's arms, and, with a bright look of inspiration, she ran to the very brink of the waters of the lake. "Harfang! Harfang!" cried she in a clear voice; "here! come to me!"

The faithful bird, surprised, appeared to hesitate in its flight. Presently, recognizing Nell's voice, it dropped the burning match into the water, and, describing a wide circle, flew downwards, alighting at the maiden's feet.