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. Starr," returned old Simon. "The old 'Monk' is mad enough now, at any rate!"

"All the better," quoth Madge.

"I don't know that," said Starr, shaking his head; "it is a terrible sort of madness this."

"Ah! now I understand that the very thought of him must have terrified poor little Nell, and also I see that she could not bear to denounce her grandfather. What a miserable time she must have had of it with the old man!"

"Miserable with a vengeance," replied Simon, "between that savage and his owl, as savage as himself. Depend upon it, that bird isn't dead. That was what put our lamp out, and also so nearly cut the rope by which Harry and Nell were suspended."

"And then, you see," said Madge, "this news of the marriage of our son with his granddaughter added to his rancor and ill-will."

"To be sure," said Simon. "To think that his Nell should marry one of the robbers of his own coal mine would just drive him wild altogether."

"He will have to make up his mind to it, however," cried Harry. "Mad as he is, we shall manage to convince him that Nell is better off with us here than ever she was in the caverns of the pit. I am sure, Mr. Starr, if we could only catch him, we should be able to make him listen to reason."

"My poor Harry! there is no reasoning with a madman," replied the engineer. "Of course it is better to know your enemy than not; but you must not fancy all is right because we have found out who he is. We must be on our guard, my friends; and to begin with, Harry, you positively must question Nell. She will perceive that her silence is no longer reasonable. Even for her grandfather's own interest, she ought to speak now. For his own sake, as well as for ours, these insane plots must be put a stop to."

"I feel sure, Mr. Starr," answered Harry, "that Nell will of herself propose to tell you what she knows. You see it was from a sense of duty that she has been silent hitherto. My mother was very right to take her to her room just now. She much needed time to recover her spirits; but now I will go for her."

"You need not do so, Harry," said the maiden in a clear and firm voice, as she entered at that moment the room in which they were. Nell was very pale; traces of tears were in her eyes; but her whole manner showed that she had nerved herself to act as her loyal heart dictated as her duty.

"Nell!" cried Harry, springing towards her.

The girl arrested her lover by a gesture, and continued, "Your father and mother, and you, Harry, must now know all. And you too, Mr. Starr, must remain ignorant of nothing that concerns the child you have received, and whom Harry--unfortunately for him, alas!--drew from the abyss."

"Oh, Nell! what are you saying?" cried Harry.

"Allow her to speak," said James Starr in a decided tone.

"I am the granddaughter of old Silfax," resumed Nell. "I never knew a mother till the day I came here," added she, looking at Madge.

"Blessed be that day, my daughter!" said the old woman.

"I knew no father till I saw Simon Ford," continued Nell; "nor friend till the day when Harry's hand touched mine. Alone with my grandfather I have lived during fifteen years in the remote and most solitary depths of the mine. I say WITH my grandfather, but I can scarcely use the expression, for I seldom saw him. When he disappeared from Old Aberfoyle, he concealed himself in caverns known only to himself. In his way he was kind to me, dreadful as he was; he fed me with whatever he could procure from outside the mine; but I can dimly recollect that in my earliest years I was the nursling of a goat, the death of which was a bitter grief to me. My grandfather, seeing my distress, brought me another animal--a dog he said it was. But, unluckily, this dog was lively, and barked. Grandfather did not like anything cheerful. He had a horror of noise, and had ............