M. Formery gasped: "The real track?" he muttered.
 
"Let me show you," said Guerchard. And he led him to the fireplace, and showed him the opening between the two houses.
 
"I must go into this myself!" cried M. Formery in wild excitement.
 
Without more ado he began to mount the steps. Guerchard followed him. The Duke saw their heels disappear up the steps. Then he came out of the drawing-room and inquired for M. Gournay-Martin. He was told that the millionaire was up in his bedroom; and he went upstairs, and knocked at the door of it.
 
M. Gournay-Martin bade him enter in a very faint voice, and the Duke found him lying on the bed. He was looking depressed, even exhausted, the shadow of the blusterous Gournay-Martin of the day before. The rich rosiness of his cheeks had faded to a moderate rose-pink.
 
"That telegram," moaned the millionaire. "It was the last straw. It has overwhelmed me. The coronet is lost."
 
"What, already?" said the Duke, in a tone of the liveliest surprise.
 
"No, no; it's still in the safe," said the millionaire. "But it's as good as lost—before midnight it will be lost. That fiend will get it."
 
"If it's in this safe now, it won't be lost before midnight," said the Duke. "But are you sure it's there now?"
 
"Look for yourself," said the millionaire, taking the key of the safe from his waistcoat pocket, and handing it to the Duke.
 
The Duke opened the safe. The morocco case which held the coronet lay on the middle shell in front of him. He glanced at the millionaire, and saw that he had closed his eyes in the exhaustion of despair. Whistling softly, the Duke opened the case, took out the diadem, and examined it carefully, admiring its admirable workmanship. He put it back in the case, turned to the millionaire, and said thoughtfully:
 
"I can never make up my mind, in the case of one of these old diadems, whether one ought not to take out the stones and have them re-cut. Look at this emerald now. It's a very fine stone, but this old-fashioned cutting does not really do it justice."
 
"Oh, no, no: you should never interfere with an antique, historic piece of jewellery. Any alteration decreases its value—its value as an historic relic," cried the millionaire, in a shocked tone.
 
"I know that," said the Duke, "but the question for me is, whether one ought not to sacrifice some of its value to increasing its beauty."
 
"You do have such mad ideas," said the millionaire, in a tone of peevish exasperation.
 
"Ah, well, it's a nice question," said the Duke.
 
He snapped the case briskly, put it back on the shelf, locked the safe, and handed the key to the millionaire. Then he strolled across the room and looked down into the street, whistling softly.
 
"I think—I think—I'll go home and get out of these motoring clothes. And I should like to have on a pair of boots that were a trifle less muddy," he said slowly.
 
M. Gournay-Martin sat up with a jerk and cried, "For Heaven's sake, don't you go and desert me, my dear chap! You don't know what my nerves are like!"
 
"Oh, you've got that sleuth-hound, Guerchard, and the splendid Formery, and four other detectives, and half a dozen ordinary policemen guarding you. You can do without my feeble arm. Besides, I shan't be gone more than half an hour—three-quarters at the outside. I'll bring back my evening clothes with me, and dress for dinner here. I don't suppose that anything fresh will happen between now and midnight; but I want to be on the spot, and hear the information as it comes in fresh. Besides, there's Guerchard. I positively cling to Guerchard. It's an education, though perhaps not a liberal education, to go about with him," said the Duke; and there was a sub-acid irony in his voice.
 
"Well, if you must, you must," said M. Gournay-Martin grumpily.
 
"Good-bye for the present, then," said the Duke. And he went out of the room and down the stairs. He took his motor-cap from the hall-table, and had his hand on the latch of the door, when the policeman in charge of it said, "I beg your pardon, sir, but have you M. Guerchard's permission to leave the house?"
 
"M. Guerchard's permission?" said the Duke haughtily. "What has M. Guerchard to do with me? I am the Duke of Charmerace." And he opened the door.
 
"It was M. Formery's orders, your Grace," stammered the policeman doubtfully.
 
"M. Formery's orders?" said the Duke, standing on the top step. "Call me a taxi-cab, please."
 
The concierge, who stood beside the policeman, ran down the steps and blew his whistle. The policeman gazed uneasily at the Duke, shifting his weight from one foot to the other; but he said no more.
 
A taxi-cab came up to the door, the Duke went down the steps, stepped into it, and drove away.
 
Three-quarters of an hour later he came back, having changed into clothes more suited to a Paris drawing-room. He went up to the drawing-room, and there he found Guerchard, M. Formery, and the inspector, who had just completed their tour of inspection of the house next door and had satisfied themselves that the stolen treasures were not in it. The inspector and his men had searched it thoroughly just to make sure; but, as Guerchard had foretold, the burglars had not taken the chance of the failure of the police to discover the opening between the two houses. M. Formery told the Duke about their tour of inspection at length. Guerchard went to the telephone and told the exchange to put him through to Charmerace. He was informed that the trunk line was very busy and that he might have to wait half an hour.
 
The Duke inquired if any trace of the burglars, after they had left with their booty, had yet been found. M. Formery told him that, so far, the detectives had failed to find a single trace. Guerchard said that he had three men at work on the search, and that he was hopeful of getting some news before long.
 
"The layman is impatient in these matters," said M. Formery, with an indulgent smile. "But we have learnt to be patient, after long experience."
 
He proceeded to discuss with Guerchard the new theories with which the discovery of the afternoon had filled his mind. None of them struck the Duke as being of great value, and he listened to them with a somewhat absent-minded air. The coming examination of Sonia weighed heavily on his spirit. Guerchard answered only in monosyllables to the questions and suggestions thrown out by M. Formery. It seemed to the Duke that he paid very little attention to him, that his mind was still working hard on the solution of the mystery, seeking the missing facts which would bring him to the bottom of it. In the middle of one of M. Formery's more elaborate dissertations the telephone bell rang.
 
Guerchard rose hastily and went to it. They heard him say: "Is that Charmerace? ... I want the gardener.... Out? When will he be back? ... Tell him to ring me up at M. Gournay-Martin's house in Paris the moment he gets back............