took possession of me.  Then the uncanny noises that make all old houses ghostly during the small hours began to make themselves heard.  Muffled footsteps trod the corridor, stopping to listen at every door, door latches gently clicked, boards creaked unreasonably, sounds of stealthy movements came from the locked-up bathroom.  The welcome crash of wheels at last, and the sound of the front-door bell.  I could hear Lady Carwitchet making her shrill adieux to her friends and her steps in the corridor.  She was softly humming a little song as she approached.  I heard her unlock her bedroom door before she entered—­an odd thing to do.  Tom came sleepily stumbling to his room later.  I put my head out.  “Where is Lord Carwitchet?”

“Haven’t you seen him?  He left us hours ago.  Not come home, eh?  Well, he’s welcome to stay away.  I don’t want to see more of him.”  Tom’s brow was dark and his voice surly.  “I gave him to understand as much.”  Whatever had happened, Tom was evidently too disgusted to explain just then.

I went back to my fire unaccountably relieved, and brewed myself another and a stronger brew.  It warmed me this time, but excited me foolishly.  There must be some way out of the difficulty.  I felt now as if I could almost see it if I gave my mind to it.  Why—­suppose—­there might be no difficulty after all!  The bishop was a nervous old gentleman.  He might have been mistaken all through, Bogaerts might have been mistaken, I might—­no.  I could not have been mistaken—­or I thought not.  I fidgeted and fumed and argued with myself till I found I should have no peace of mind without a look at the stone in my possession, and I actually went to the safe and took the case out.

The sapphire certainly looked different by lamplight.  I sat and stared, and all but overpersuaded my better judgment into giving it a verdict.  Bogaerts’s mark—­I suddenly remembered it.  I took my magnifier and held the pendant to the light.  There, scratched upon the stone, was the Greek Beta!  There came a tap on my door, and before I could answer, the handle turned softly and Lord Carwitchet stood before me.  I whipped the case into my dressing-gown pocket and stared at him.  He was not pleasant to look at, especially at that time of night.  He had a disheveled, desperate air, his voice was hoarse, his red-rimmed eyes wild.

“I beg your pardon,” he began civilly enough.  “I saw your light burning, and thought, as we go by the early train to-morrow, you might allow me to consult you now on a little business of my mother’s.”  His eyes roved about the room.  Was he trying to find the whereabouts of my safe?  “You know a lot about precious stones, don’t you?”

“So my friends are kind enough to say.  Won’t you sit down?  I have unluckily little chance of indulging the taste on my own account,” was my cautious reply.

“But you’ve written a book about them, and know them when you see them, don’t you?  Now my mother has given me something, and would like you to give a guess at its value.  Perhaps you can put me in the way of disposing of it?”