And suddenly, Mr. Ricardo began to reflect. What, after all, could he have told them?

And that question he turned over in his mind while he ate his luncheon.

Hanaud wrote a letter between the courses. They were sitting at a corner table, and Hanaud was in the corner with his back to the wall.

He moved his plate, too, over the letter as he wrote it. It would have been impossible for either of his guests to see what he had written, even if they had wished. Ricardo, indeed, did wish. He rather resented the secrecy with which the detective, under a show of openness, shrouded his thoughts and acts. Hanaud sent the waiter out to fetch an officer in plain clothes, who was in attendance at the door, and he handed the letter to this man. Then he turned with an apology to his guests.

"It is necessary that we should find out," he explained, "as soon as possible, the whole record of Mlle. Celie."

He lighted a cigar, and over the coffee he put a question to Ricardo.

"Now tell me what you make of the case. What M. Wethermill thinks--that is clear, is it not? Helene Vauquier is the guilty one. But you, M.

Ricardo? What is your opinion?"

Ricardo took from his pocket-book a sheet of paper and from his pocket a pencil. He was intensely flattered by the request of Hanaud, and he proposed to do himself justice. "I will make a note here of what I think the salient features of the mystery"; and he proceeded to tabulate the points in the following way:

(1) Celia Harland made her entrance into Mme. Dauvray's household under very doubtful circ.u.mstances.

(2) By methods still more doubtful she acquired an extraordinary ascendency over Mme. Dauvray's mind.

(3) If proof were needed how complete that ascendency was, a glance at Celia Harland's wardrobe would suffice; for she wore the most expensive clothes.

(4) It was Celia Harland who arranged that Servettaz, the chauffeur, should be absent at Chambery on the Tuesday night--the night of the murder.

(5) It was Celia Harland who bought the cord with which Mme. Dauvray was strangled and Helene Vauquier bound.

(6) The footsteps outside the salon show that Celia Harland ran from the salon to the motor-car.

(7) Celia Harland pretended that there should be a seance on the Tuesday, but she dressed as though she had in view an appointment with a lover, instead of a spiritualistic seance.

(8) Celia Harland has disappeared.

These eight points are strongly suggestive of Celia Harland's complicity in the murder. But I have no clue which will enable me to answer the following questions:

(a) Who was the man who took part in the crime? (b) Who was the woman who came to the villa on the evening of the murder with Mme. Dauvray and Celia Harland?

(c) What actually happened in the salon? How was the murder committed?

(d) Is Helene Vauquier's story true?

(e) What did the torn-up sc.r.a.p of writing mean? (Probably spirit writing in Celia Harland's hand.)

(f) Why has one cushion on the settee a small, fresh, brown stain, which is probably blood? Why is the other cushion torn?

Mr. Ricardo had a momentary thought of putting down yet another question. He was inclined to ask whether or no a pot of cold cream had disappeared from Celia Harland's bedroom; but he remembered that Hanaud had set no store upon that incident, and he refrained. Moreover, he had come to the end of his sheet of paper. He handed it across the table to Hanaud and leaned back in his chair, watching the detective with all the eagerness of a young author submitting his first effort to a critic.

Hanaud read it through slowly. At the end he nodded his head in approval.

"Now we will see what M. Wethermill has to say," he said, and he stretched out the paper towards Harry Wethermill, who throughout the luncheon had not said a word.

"No, no," cried Ricardo.

But Harry Wethermill already held the written sheet in his hand. He smiled rather wistfully at his friend.

"It is best that I should know just what you both think," he said, and in his turn he began to read the paper through. He read the first eight points, and then beat with his fist upon the table.

"No no," he cried; "it is not possible! I don't blame you, Ricardo.

These are facts, and, as I said, I can face facts. But there will be an explanation--if only we can discover it."

He buried his face for a moment in his hands. Then he took up the paper again.

"As for the rest, Helene Vauquier lied," he cried violently, and he tossed the paper to Hanaud. "What do you make of it?"

Hanaud smiled and shook his head.

"Did you ever go for a voyage on a ship?" he asked.

"Yes; why?"

"Because every day at noon three officers take an observation to determine the ship's position--the captain, the first officer, and the second officer. Each writes his observation down, and the captain takes the three observations and compares them. If the first or second officer is out in his reckoning, the captain tells him so, but he does not show his own. For at times, no doubt, he is wrong too. So, gentlemen, I criticise your observations, but I do not show you mine."

He took up Ricardo's paper and read it through again.

"Yes," he said pleasantly. "But the two questions which are most important, which alone can lead us to the truth--how do they come to be omitted from your list, Mr. Ricardo?"

Hanaud put the question with his most serious air. But Ricardo was none the less sensible of the raillery behind the solemn manner. He flushed and made no answer.

"Still," continued Hanaud, "here are undoubtedly some questions. Let us consider them! Who was the man who took a part in the crime? Ah, if we only knew that, what a lot of trouble we should save ourselves! Who was the woman? What a good thing it would be to know that too! How clearly, after all, Mr. Ricardo puts his finger on the important points! What did actually happen in the salon?" And as he quoted that question the raillery died out of his voice. He leaned his elbows on the table and bent forward.

"What did actually happen in that little pretty room, just twelve hours ago?" he repeated. "When no sunlight blazed upon the lawn, and all the birds were still, and all the windows shuttered and the world dark, what happened? What dreadful things happened? We have not much to go upon. Let us formulate what we know. We start with this. The murder was not the work of a moment. It was planned with great care and cunning, and carried out to the letter of the plan. There must be no noise, no violence. On each side of the Villa Rose there are other villas; a few yards away the road runs past. A scream, a cry, the noise of a struggle--these sounds, or any one of them, might be fatal to success.

Thus the crime was planned; and there WAS no scream, there WAS no struggle. Not a chair was broken, and only a chair upset. Yes, there were brains behind that murder. We know that. But what do we know of the plan? How far can we build it up? Let us see. First, there was an accomplice in the house--perhaps two."

"No!" cried Harry Wethermill.

Hanaud took no notice of the interruption.

"Secondly the woman came to the house with Mme. Dauvray and Mlle. Celie between nine and half-past nine. Thirdly, the man came afterwards, but before eleven, set open the gate, and was admitted into the salon, unperceived by Mme. Dauvray. That also we can safely a.s.sume. But what happened in the salon? Ah! There is the question." Then he shrugged his shoulders and said with the note of raillery once more in his voice:

"But why should we trouble our heads to puzzle out this mystery, since M. Ricardo knows?"

"I?" cried Ricardo in amazement.

"To be sure," replied Hanaud calmly. "For I look at another of your questions. 'WHAT DID THE TORN-UP Sc.r.a.p OF WRITING MEAN?' and you add: 'Probably spirit-writing.' Then there was a seance held last night in the little salon! Is that so?"

Harry Wethermill started. Mr. Ricardo was at a loss.

"I had not followed my suggestion to its conclusion," he admitted humbly.

"No," said Hanaud. "But I ask myself in sober earnest, 'Was there a seance held in the salon last night?' Did the tambourine rattle in the darkness on the wall?"