members of that unique dinner-party.
At the very moment in which Lupin left me, Herlock Sholmes rose from the table, and looked at his watch.
"Twenty minutes to nine. At nine o'clock I am to meet the Count and Countess at the railway station."
"Then, we must be off!" exclaimed Wilson, between two drinks of whisky.
They left the restaurant.
"Wilson, don't look behind. We may be followed, and, in that case, let us act as if we did not care. Wilson, I want your opinion: why was Lupin in that restaurant?"
"To get something to eat," replied Wilson, quickly.
"Wilson, I must congratulate you on the accuracy of your deduction. I couldn't have done better myself."
Wilson blushed with pleasure, and Sholmes continued:
"To get something to eat. Very well, and, after that, probably, to assure himself whether I am going to the Château de Crozon, as announced by Ganimard in his interview. I must go in order not to disappoint him. But, in order to gain time on him, I shall not go."
"Ah!" said Wilson, nonplused.
"You, my friend, will walk down this street, take a carriage, two, three carriages. Return later and get the valises that we left at the station, and make for the Elysée-Palace at a galop."
"And when I reach the Elysée-Palace?"
"Engage a room, go to sleep, and await my orders."
Quite proud of the important rôle assigned to him, Wilson set out to perform his task. Herlock Sholmes proceeded to the railway station, bought a ticket, and repaired to the Amiens' express in which the Count and Countess de Crozon were already installed. He bowed to them, lighted his pipe, and had a quiet smoke in the corridor. The train started. Ten minutes later he took a seat beside the Countess, and said to her:
"Have you the ring here, madame?"
"Yes."
"Will you kindly let me see it?"
He took it, and examined it closely.
"Just as I suspected: it is a manufactured diamond."
"A manufactured diamond?"
"Yes; a new process which consists in submitting diamond dust to a tremendous heat until it melts and is then molded into a single stone."
"But my diamond is genuine."
"Yes, your diamond is; but this is not yours."
"Where is mine?"
"It is held by Arsène Lupin."
"And this stone?"
"Was substituted for yours, and slipped into Herr Bleichen's tooth-powder, where it was afterwards found."
"Then you think this is false?"
"Absolutely false."
The Countess was overwhelmed with surprise and grief, while her husband scrutinized the diamond with an incredulous air. Finally she stammered:
"Is it possible? And why did they not merely steal it and be done with it? And how did they steal it?"
"That is exactly what I am going to find out."
"At the Château de Crozon?"
"No. I shall leave the train at Creil and return to Paris. It is there the game between me and Arsène Lupin must be played. In fact, the game has commenced already, and Lupin thinks I am on my way to the château."
"But—"
"What does it matter to you, madame? The essential thing is your diamond, is it not?"
"Yes."
"Well, don't worry. I have just undertaken a much more difficult task than that. You have my promise that I will restore the true diamond to you within ten days."
The train slackened its speed. He put the false diamond in his pocket and opened the door. The Count cried out:
"That is the wrong side of the train. You are getting out on the tracks."
"That is my intention. If Lupin has anyone on my track, he will lose sight of me now. Adieu."
An employee protested in vain. After the departure of the train, the Englishman sought the station-master's office. Forty minutes later he leaped into a train that landed him in Paris shortly before midnight. He ran across the platform, entered the lunch-room, made his exit at another door, and jumped into a cab.
"Driver—rue Clapeyron."
Having reached the conclusion that he was not followed, he stopped the carriage at the end of the street, and proceeded to make a careful examination of Monsieur Detinan's house and the two adjoining houses. He made measurements of certain distances and entered the figures in his notebook.
"Driver—avenue Henri-Martin."
At the corner of the avenue and the rue de la Pompe, he dismissed the carriage, walked down the street to number 134, and performed the same operations in front of the house of the late Baron d'Hautrec and the two adjoining houses, measuring the width of the respective façades and calculating the depth of the little gardens that stood in front of them.
The avenue was deserted, and was very dark under its four rows of trees, between which, at considerable intervals, a few gas-lamps struggled in vain to light the deep shadows. One of them threw a dim light over a portion of the house, and Sholmes perceived the "To-let" sign posted on the gate, the neglected walks which encircled the small lawn, and the large bare windows of the vacant house.
"I suppose," he said to himself, "the house has been unoccupied since the death of the baron.... Ah! if I could only get in and view the scene of the murder!"
No sooner did the idea occur to him than he sought to put it in execution. But how could he manage it? He could not climb over the gate; it was too high. So he took from his pocket an electric lantern and a skeleton key which he always carried. Then, to his great surprise, he discovered that the gate was not locked; in fact, it was open about three or four inches. He entered the garden, and was careful to leave the gate as he had found it—partly open. But he had not taken many steps from the gate when he stopped. He had seen a light pass one of the windows on the second floor.
He saw the light pass a second window and a third, but he saw nothing else, except a silhouette outlined on the walls of the rooms. The light descended to the first floor, and, for a long time, wandered from room to room.
"Who the deuce is walking, at one o'clock in the morning, through the house in which the Baron d'Hautrec was killed?" Herlock Sholmes asked himself, deeply interested.
There was only one way to find out, and that was to enter the house himself. He did not hesitate, but started for the door of the house. However, at the moment when he crossed the streak of gaslight that came from the street-lamp, the man must have seen him, for the light in the house was suddenly extinguished and Herlock Sholmes did not see it again. Softly, he tried the door. It was open, also. Hearing no sound, he advanced through the hallway, encountered the foot of the stairs, and ascended to the first floor. Here there was the same silence, the same darkness.
He entered, one of the rooms and approached a window through which came a feeble light from the outside. On looking through the window he saw the man, who had no doubt descended by another stairway and escaped by another door. The man was threading his way through the shrubbery which bordered the wall that separated the two gardens.
"The deuce!" exclaimed Sholmes, "he is going to escape."
He hastened down the stairs and leaped over the steps in his eagerness to cut off the man's retreat. But he did not see anyone, and, owing to the darkness, it was several seconds before he was able to distinguish a bulky form moving through the shrubbery. This gave the Englishman food for reflection. Why had the man not made his escape, which he could have done so easily? Had he remained in order to watch the movements of the intruder who