They had gone to the large dining-hall in the old mansion.  Horace sometimes used it as a smoking-room, but otherwise it was seldom visited, except when the house was full of guests and all the old part was thrown open.

It was a long and high room, finished in dark wood, and decorated with moldering portraits in the worst possible style of art.

At one end was a gigantic fire-place, which was closed by a screen of boards.

“He told me,” continued Horace, “that he was passing through here late last night—­near midnight, he said—­and that he saw Lavina Richmond standing just about where you stand now.

“He came in by that door, behind me, and she was directly facing him.  He says that he didn’t move or yell, or do anything, but just stood staring at her.

“She paid no attention whatever to him, but passed across the room and went out by that other door, which opened as she approached and closed after her of itself.

“Then he ran for his room.  He claims that he wasn’t scared—­only a bit nervous.

“You can believe that if you want to.  I tell you that he was scared, so that he won’t get over it in a year.

“If it wasn’t for that I might think he was lying; but when a man like Gilder quietly invites the footman—­whom he always hated—­to take half of his bed for a few weeks, it’s a sure thing that he’s seen something out of the ordinary.

“And the footman, as I learn, was mighty glad to accept the invitation, for he’s been having a few experiences of his own.

“Now, Mr. Carter, you and I believe that these things are done by some clever trickster.  It may be that some bogus medium who used to get the colonel’s good money away from him, wants more of it, and is taking this means of driving my uncle back to the fold of true believers.

“I’m beginning to believe that that may be the fact.  But whatever it is, the case is almighty serious.

“Here’s a nice old man, living happily, and gradually getting away from his delusion.  Here’s an agent of the devil trying to drive this old man back to his delusion, and make a lunatic of him, for that’s what the doctor says will certainly happen.

“I say it’s too bad, not to mention the jewels at all.  Now, what are we going to do about it?”

“Catch the rascal,” said Nick, promptly, “and catch him mighty quick.”

“Well, I hope you’ll succeed.  I tell you, Mr. Carter, I feel toward Colonel Richmond all the affection that I would give my father, if he were alive, and I can’t bear to see him driven out of his wits in this infernal way.”

“Have no fear,” said Nick; “we’ll save him.  This trickery with the servants may give us a chance to catch our man.”

They returned to the parlor in the new part of the house.

Colonel Richmond was not there.

“Where is he?” asked Horace, anxiously, of Mrs. Pond.

“He has gone to his room.  He said that the excitement of this affair had worn him out completely.”