He looked at his ring, which was formed of a large, clouded, dead turquoise, surrounded by a circle of small, irregular turquoises, also of a very pale blue. One of these was missing; and the one which M.

Desmalions had in his hand fitted the place exactly.

"What do you say?" asked M. Desmalions.

"I say that this turquoise belongs to my ring, which was given me by Cosmo Mornington on the first occasion that I saved his life."

"So we are agreed?"

"Yes, Monsieur le Prefet, we are agreed."

Don Luis Perenna began to walk across the room, reflecting. The movement which the two detectives made toward the two doors told him that his arrest was provided for. A word from M. Desmalions, and Sergeant Mazeroux would be forced to take his chief by the collar.

Don Luis once more gave a glance toward his former accomplice. Mazeroux made a gesture of entreaty, as though to say:

"Well, what are you waiting for? Why don't you give up the criminal?

Quick, it's time!"

Don Luis smiled.

"What's the matter?" asked the Prefect, in a tone that now entirely lacked the sort of involuntary politeness which he had shown since the commencement of the examination.

"The matter? The matter?--"

Perenna seized a chair by the back, spun it round and sat down upon it, with the simple remark:

"Let's talk!"

And this was said in such a way and the movement executed with so much decision that the Prefect muttered, as though wavering:

"I don't quite see--"

"You soon will, Monsieur le Prefet."

And, speaking in a slow voice, laying stress on every syllable that he uttered, he began:

"Monsieur le Prefet, the position is as clear as daylight. Yesterday evening you gave me an authorization which involves your responsibility most gravely. The result is that what you now want, at all costs and without delay, is a culprit. And that culprit is to be myself. By way of incriminating evidence, you have the fact of my presence here, the fact the door was locked on the inside, the fact that Sergeant Mazeroux was asleep while the crime was committed, and the fact of the discovery of the turquoise in the safe. All this is crushing, I admit. Added to it,"

he continued, "we have the terrible presumption that I had every interest in the removal of M. Fauville and his son, inasmuch as, if there is no heir of Cosmo Mornington's in existence, I come into a hundred million francs. Exactly. There is therefore nothing for me to do, Monsieur le Prefet, but to go with you to the lockup or else--"

"Or else what?"

"Or else hand over to you the criminal, the real criminal."

The Prefect of Police smiled and took out his watch.

"I'm waiting," he said.

"It will take me just an hour, Monsieur le Prefet, and no more, if you give me every lat.i.tude. And the search of the truth, it seems to me, is worth a little patience."

"I'm waiting," repeated M. Desmalions.

"Sergeant Mazeroux, please tell Silvestre, the manservant, that Monsieur le Prefet wishes to see him."

Upon a sign from M. Desmalions, Mazeroux went out.

Don Luis explained his motive.

"Monsieur le Prefet, whereas the discovery of the turquoise const.i.tutes in your eyes an extremely serious proof against me, to me it is a revelation of the highest importance. I will tell you why. That turquoise must have fallen from my ring last evening and rolled on the carpet.

"Now there are only four persons," he continued, "who can have noticed this fall when it happened, picked up the turquoise and, in order to compromise the new adversary that I was, slipped it into the safe. The first of those four persons is one of your detectives, Sergeant Mazeroux, of whom we will not speak. The second is dead: I refer to M. Fauville. We will not speak of him. The third is Silvestre, the manservant. I should like to say a few words to him. I shall not take long."

Silvestre's examination, in fact, was soon over. He was able to prove that, pending the return of Mme. Fauville, for whom he had to open the door, he had not left the kitchen, where he was playing at cards with the lady's maid and another manservant.

"Very well," said Perenna. "One word more. You must have read in this morning's papers of the death of Inspector Verot and seen his portrait."

"Yes."

"Do you know Inspector Verot?"

"No."

"Still, it is probable that he came here yesterday, during the day."

"I can't say," replied the servant. "M. Fauville used to receive many visitors through the garden and let them in himself."

"You have no more evidence to give?"

"No."

"Please tell Mme. Fauville that Monsieur le Prefet would be very much obliged if he could have a word with her."

Silvestre left the room.

The examining magistrate and the public prosecutor had drawn nearer in astonishment.

The Prefect exclaimed:

"What, Monsieur! You don't mean to pretend that Mme. Fauville is mixed up--"

"Monsieur le Prefet, Mme. Fauville is the fourth person who may have seen the turquoise drop out of my ring."

"And what then? Have we the right, in the absence of any real proof, to suppose that a woman can kill her husband, that a mother can poison her son?"

"I am supposing nothing, Monsieur le Prefet."

"Then--?"

Don Luis made no reply. M. Desmalions did not conceal his irritation.

However, he said: