Harry, your son, has robbed me of Nell. Woe betide you! Woe betide you all! Woe betide New Aberfoyle!--SILFAX."

"Silfax!" exclaimed Simon and Madge together.

"Who is this man?" demanded Harry, looking alternately at his father and at the maiden.

"Silfax!" repeated Nell in tones of despair, "Silfax!"--and, murmuring this name, her whole frame shuddering with fear and agitation, she was borne away to her chamber by old Madge.

James Starr, hastening to the spot, read the threatening sentences again and again.

"The hand which traced these lines," said he at length, "is the same which wrote me the letter contradicting yours, Simon. The man calls himself Silfax. I see by your troubled manner that you know him. Who is this Silfax?"

CHAPTER XVII THE "MONK"

THIS name revealed everything to the old overman. It was that of the last "monk" of the Dochart pit.

In former days, before the invention of the safety-lamp, Simon had known this fierce man, whose business it was to go daily, at the risk of his life, to produce partial explosions of fire-damp in the passages. He used to see this strange solitary being, prowling about the mine, always accompanied by a monstrous owl, which he called Harfang, who assisted him in his perilous occupation, by soaring with a lighted match to places Silfax was unable to reach.

One day this old man disappeared, and at the same time also, a little orphan girl born in the mine, who had no relation but himself, her great-grandfather. It was perfectly evident now that this child was Nell. During the fifteen years, up to the time when she was saved by Harry, they must have lived in some secret abyss of the mine.

The old overman, full of mingled compassion and anger, made known to the engineer and Harry all that the name of Silfax had revealed to him. It explained the whole mystery. Silfax was the mysterious being so long vainly sought for in the depths of New Aberfoyle.

"So you knew him, Simon?" demanded Mr. Starr.

"Yes, that I did," replied the overman. "The Harfang man, we used to call him. Why, he was old then! He must be fifteen or twenty years older than I am. A wild,

savage sort of fellow, who held aloof from everyone and was known to fear nothing--neither fire nor water. It was his own fancy to follow the trade of 'monk,' which few would have liked. The constant danger of the business had unsettled his brain. He was prodigiously strong, and he knew the mine as no one else-- at any rate, as well as I did. He lived on a small allowance. In faith, I believed him dead years ago."

"But," resumed James Starr, "what does he mean by those words, 'You have robbed me of the last vein of our old mine'?"

"Ah! there it is," replied Simon; "for a long time it had been a fancy of his--I told you his mind was deranged-- that he had a right to the mine of Aberfoyle; so he became more and more savage in temper the deeper the Dochart pit-- his pit!--was worked out. It just seemed as if it was his own body that suffered from every blow of the pickax. You must remember that, Madge?"

"Ay, that I do, Simon," replied she.

"I can recollect all this," resumed Simon, "since I have seen the name of Silfax on the door. But I tell you, I thought the man was dead, and never imagined that the spiteful being we have so long sought for could be the old fireman of the Dochart pit."

"Well, now, then," said Starr, "it is all quite plain. Chance made known to Silfax the new vein of coal. With the egotism of madness, he believed himself the owner of a treasure he must conceal and defend. Living in the mine, and wandering about day and night, he perceived that you had discovered the secret, and had written in all haste to beg me to come. Hence the letter contradicting yours; hence, after my arrival, all the accidents that occurred, such as the block of stone thrown at Harry, the broken ladder at the Yarrow shaft, the obstruction of the openings into the wall of the new cutting; hence, in short, our imprisonment, and then our deliverance, brought about by the kind assistance of Nell, who acted of course without the knowledge of this man Silfax, and contrary to his intentions."

"You describe everything exactly as it must have happened, Mr.