But, once more, what possible interest could any human being have in the destruction of our works?"

"It is quite incomprehensible," replied James Starr. "This case is something perfectly unlike that of a band of common criminals, who, concealing themselves in dens and caves, go forth to rob and pillage the surrounding country. The evil deeds of such men would certainly, in the course of three years have betrayed their existence and lurking-places. Neither can it be, as I sometimes used to think, that smugglers or coiners carried on their illegal practices in some distant and unknown corner of these prodigious caverns, and were consequently anxious to drive us out of them. But no one coins false money or obtains contraband goods only to conceal them!

"Yet it is clear that an implacable enemy has sworn the ruin of New Aberfoyle, and that some interest urges him to seek in every possible way to wreak his hatred upon us. He appears to be too weak to act openly, and lays his schemes in secret; but displays such intelligence as to render him a most formidable foe.

"My friends, he must understand better than we do the secrets of our domain, since he has all this time eluded our vigilance. He must be a man experienced in mining, skilled beyond the most skillful-- that's certain, Simon! We have proof enough of that.

"Let me see! Have you never had a personal enemy, to whom your suspicions might point? Think well! There is such a thing as hatred which time never softens. Go back to recollections of your earliest days. What befalls us appears the work of a stern and patient will, and to explain it demands every effort of thought and memory."

Simon did not answer immediately--his mind evidently engaged in a close and candid survey of his past life. Presently, raising his head, "No," said he; "no! Heaven be my witness, neither Madge nor I have ever injured anybody. We cannot believe that we have a single enemy in the world."

"Ah! if Nell would only speak!" cried the engineer.

"Mr. Starr--and you, father," said Harry, "I do beg of you to keep silence on this matter, and not to question my poor Nell. I know she is very anxious and uneasy; and I feel positive that some great secret painfully oppresses her heart. Either she knows nothing it would be of any use for us to hear, or she considers it her duty to be silent. It is impossible to doubt her affection for us--for all of us. If at a future time she informs me of what she has hitherto concealed from us, you shall know about it immediately."

"So be it, then, Harry," answered the engineer; "and yet I must say Nell's silence, if she knows anything, is to me perfectly inexplicable."

Harry would have continued her defense; but the engineer stopped him, saying, "All right, Harry; we promise to say no more about it to your future wife."

"With my father's consent she shall be my wife without further delay."

"My boy," said old Simon, "your marriage shall take place this very day month. Mr. Starr, will you undertake the part of Nell's father?"

"You may reckon upon me for that, Simon," answered the engineer.

They then returned to the cottage, but said not a word of the result of their examinations in the mine, so that to the rest of its inhabitants, the bursting in of the vaulted roof of the caverns continued to be regarded as a mere accident. There was but a loch the less in Scotland.

Nell gradually resumed her customary duties, and Harry made good use of her little visit to the upper air, in the instructions he gave her. She enjoyed the recollections of life above ground, yet without regretting it. The somber region she had loved as a child, and in which her wedded life would be spent, was as dear to her as ever.

The approaching marriage created great excitement in New Aberfoyle. Good wishes poured in on all sides, and foremost among them were Jack Ryan's. He was detected busily practicing his best songs in preparation for the great

day, which was to be celebrated by the whole population of Coal Town.