He thereupon passed the whole of Rosanna’s proceedings under review.  You are already as well acquainted with those proceedings as I am; and you will understand how unanswerably this part of his report fixed the guilt of being concerned in the disappearance of the Moonstone on the memory of the poor dead girl.  Even my mistress was daunted by what he said now.  She made him no answer when he had done.  It didn’t seem to matter to the Sergeant whether he was answered or not.  On he went (devil take him!), just as steady as ever.

“Having stated the whole case as I understand it,” he said, “I have only to tell your ladyship, now, what I propose to do next.  I see two ways of bringing this inquiry successfully to an end.  One of those ways I look upon as a certainty.  The other, I admit, is a bold experiment, and nothing more.  Your ladyship shall decide.  Shall we take the certainty first?”

My mistress made him a sign to take his own way, and choose for himself.

“Thank you,” said the Sergeant.  “We’ll begin with the certainty, as your ladyship is so good as to leave it to me.  Whether Miss Verinder remains at Frizinghall, or whether she returns here, I propose, in either case, to keep a careful watch on all her proceedings—­on the people she sees, on the rides and walks she may take, and on the letters she may write and receive.”

“What next?” asked my mistress.

“I shall next,” answered the Sergeant, “request your ladyship’s leave to introduce into the house, as a servant in the place of Rosanna Spearman, a woman accustomed to private inquiries of this sort, for whose discretion I can answer.”

“What next?” repeated my mistress.

“Next,” proceeded the Sergeant, “and last, I propose to send one of my brother-officers to make an arrangement with that money-lender in London, whom I mentioned just now as formerly acquainted with Rosanna Spearman—­and whose name and address, your ladyship may rely on it, have been communicated by Rosanna to Miss Verinder.  I don’t deny that the course of action I am now suggesting will cost money, and consume time.  But the result is certain.  We run a line round the Moonstone, and we draw that line closer and closer till we find it in Miss Verinder’s possession, supposing she decides to keep it.  If her debts press, and she decides on sending it away, then we have our man ready, and we meet the Moonstone on its arrival in London.”

To hear her own daughter made the subject of such a proposal as this, stung my mistress into speaking angrily for the first time.

“Consider your proposal declined, in every particular,” she said.  “And go on to your other way of bringing the inquiry to an end.”