JOHN STAPLETON, the millionaire banker, accompanied by Richard Duvall, arrived in Paris early in the afternoon, and went at once to the former's house in the Avenue Kleber.

Upon their arrival, Duvall waited for sometime, while the distressed husband and wife were closeted together upstairs. At last they descended to the library, and Duvall was presented to Mrs. Stapleton.

The joy which her husband's arrival had caused her sent a new glow of hope to her careworn cheeks, and she greeted the detective most cordially. Clearly she felt that now something would at last be done, to find her missing child.

Duvall's first questions related to Mary Lanahan, the nurse. He was relieved to find that she had quite recovered from her sudden illness.

"Will you kindly have her brought here, Mrs. Stapleton?" he asked. "I would like to question her."In a few moments the nurse appeared. She was an extremely good-looking girl, smart and well dressed. Duvall recognized in her frank face, her clear blue eyes, the same appearance of honesty which had impressed him during his interview with Patrick Lanahan, her father.

"Mary," said Mrs. Stapleton, "this is Mr. Duvall. He is trying to find Jack for us. Tell him your story."

The girl turned to Duvall, who had risen. "I can hardly expect you to believe what I am going to say, Mr. Duvall, yet I assure you that it is the solemn truth."

"Go ahead, Miss Lanahan," said the detective. "I am prepared to believe whatever you may say."

The girl sat down, at Mrs. Stapleton's request. She still was somewhat weak, from her recent illness.

"It was a week ago last Wednesday. I left the house with Master Jack at half-past ten, and we drove to the Bois."

"Just a moment, please." Duvall stopped her with a quick gesture. "How long had you been going to the Bois in this way?"

"Over six weeks.""And you always left about the same time—half-past ten?"

"Always."

"Who accompanied you besides the child?"

"FranÇois—the chauffeur."

"Always?"

"Yes."

Duvall turned to Mrs. Stapleton. "How long has this man FranÇois been in your employ?"

"A year—in June."

"You have found him honest, reliable?"

"Always. Otherwise I should not have kept him."

The detective turned to Mary Lanahan. "Go ahead, please," he said.

"We reached the Bois shortly before eleven—FranÇois had orders to go slowly, when Master Jack was in the machine—and drove about for fifteen minutes. Then we stopped at the place where we were in the habit of playing."

"Was it always the same place?"

"Yes. There is a smooth field of grass there, and a clump of trees by the road, where the machine always waited."

"Go on.""We left the car, and walked out over the grass. Master Jack had a big rubber ball, and he was kicking it along, and running after it. Sometimes he would kick it to me, and I would throw it back to him. We played about in that way for over half an hour. Mrs. Stapleton wished the boy to have the exercise."

"I see. And you generally played about in the same place?"

"Yes."

"How far from the road?"

"About three hundred feet."

"And from the nearest bushes, or woods?"

"A little more than that, I should say."

"You could see FranÇois, in the machine, from where you were?"

"Yes, I could see the machine. I could not always see FranÇois; for sometimes he would get out, and walk about, or sit under the trees and smoke a cigarette."

"Do you remember noticing him, on this particular morning?"

"Yes. I saw him sitting in the machine."

"What was he doing?"

"Reading a newspaper."

"Had he ever done that before?"The girl hesitated, as though a new idea had come to her. "No—I cannot remember that he ever had."

"Very well. Go ahead with your story."

"Well—after we had played for about half an hour—I got tired and sat down on the grass. Master Jack still kept playing about with the ball. I sat idly, looking at the sky, the road—dreaming—"

"About what?" interrupted the detective, suddenly.

The girl colored. "About—about some people I know."

"Go ahead."

"I heard the boy playing, behind me. Then I looked around—and—he was gone!" The nurse made this statement in a voice so full of awe that it carried conviction to her hearers. Duvall felt that, whatever the real facts of the disappearance of the child, this woman's story was true.

"What did you do then?"

"I stood up and looked about. I thought Master Jack was hiding from me—playing a joke on me. Then I realized that there was no place that he could hide. The nearest trees were too far off. He could not have reached them. I called and called. I was very much frightened."

"FranÇois, who heard me, came running over the grass. I asked him if he had seen Master Jack. He said, no, that he had not seen anyone. After that we searched everywhere—in the woods, along the road—for nearly an hour, but could find nothing. Then we came home, and told Mrs. Stapleton." The girl looked at her employers in fright.

"What about the rubber ball?" Duvall asked, suddenly.

"It—it was gone."

"Then it is clear that the child must have been taken away peaceably, without objection on his part. Had he struggled, cried, he would have dropped the ball, would he not?"

"I suppose so."

"How long was your head turned from him—while you were—dreaming?"

"About a minute."

"Not more?"

"No."

"How do you estimate the time so closely?"

"I'm sure it could not have been longer. A minute is quite a long time.""What time was it when you got back to the house?"

"About—about one o'clock, I think." The girl turned to Mrs. Stapleton for confirmation of her answer.

"It was a quarter-past one," said Mrs. Stapleton, promptly. "I noted the time particularly, because it was later than usual. Mary had orders to bring Jack back for luncheon not later than one."

Duvall began to make some figures on a piece of paper. "You fix the time of the boy's disappearance at 11.30. You say you hunted for him an hour. That would be 12.30." He looked at the girl searchingly. "You arrived home at 1.15. That would mean that it took 45 minutes to get here." He turned to Stapleton. "Please send for your chauffeur, FranÇois."

Mr. Stapleton rang a bell, and ordered the servant who responded to send in the chauffeur. Meanwhile Mary Lanahan was regarding Duvall with nervous apprehension.

"We must have hunted for him longer than I thought," she said, at length.

Duvall made no reply, but waited until the arrival of the chauffeur. He proved to be a short, heavily built man, with long powerful arms, and a swarthy face—evidently from the south of France. His countenance was stolid and emotionless. He appeared the well trained servant.

Duvall addressed him at once. "How long would it take you, my man, driving fast, to reach this house from the spot in the Bois where Master Jack was lost?"

The man responded at once. "Ten minutes," he said, "easily."

"What time was it when this woman," the detective indicated the nurse, "called to you, on discovering that the child was gone?"

"I do not know."

"Have you no idea?"

"It must have been about twelve o'clock. We hunted for the boy till about one—then came home."

"The nurse says it was half-past eleven."

The man shrugged his shoulders. "It may have been. I did not observe the time."

"What were you doing?"

"I was asleep."

Mr. Stapleton started. "Asleep?" he demanded, angrily.

The man nodded. "The day was warm. I had nothing to do. For a time I read the paper. I must have dozed in my seat; for, the next thing I knew, the nurse was calling to me, and the boy was gone."

Duvall frowned. "Then you could not say whether anyone else was near the nurse and the boy, at the time he was kidnapped?"

"No, monsieur. I could not."

"That will do." The detective turned to Mr. Stapleton. "Have your man drive us to the place where all this occurred."

The banker gave the man the order, and he left the room. Then Duvall turned again to Mary Lanahan.

"You were taken suddenly ill one day last week. Tell us about it."

The woman looked up. "It was very mysterious, sir. I went out for a walk. At a cafÉ in the Rue St. HonorÉ I had a cup of chocolate."

"Alone?" asked the detective, sharply.

The woman colored. "No," she faltered. "I—I was with a friend."

"Who?"

"A—a gentleman I know." She glanced fearfully at Mr. Stapleton. "I—I would rather not give his name.""Was it Alphonse Valentin?" asked Duvall, quickly.

The woman colored still more deeply. "Yes," she replied, in scarcely audible tones.

The banker regarded her in surprise. "Alphonse Valentin!" he cried. "The fellow I discharged last year, for dishonesty? Mr. Duvall—he's your man!"

"No—no!" exclaimed the nurse, excitedly. "He knows nothing of the matter—nothing!"

"That remains to be seen," remarked Duvall, slowly. "Where did you meet this fellow, Valentin?"

"At the cafÉ in the Rue St. HonorÉ."

"You had met him there frequently before?"

"Yes."

"After you left the cafÉ, what did you do?"

"We walked to the Champs ÉlysÉes and sat on a bench, talking. Suddenly I felt very ill. Mr. Valentin called a cab and sent me home."

"Give me the address of this cafÉ, please."

The woman did so. As Duvall was entering it in his notebook, a servant announced that the automobile was at the door.In fifteen minutes the party, consisting of Mr. Stapleton, Duvall, and Mary Lanahan, were leaving the car at the spot in the Bois de Boulogne which had been the scene of the kidnapping. FranÇois was ordered to drive his machine to the exact spot, as nearly as he could tell, that it had occupied on the previous occasion. Mary Lanahan led the others to the place on the grass where she had sat.

It was evident at once that the distances she had named in telling her story were less, if anything, than the actual facts. It was quite impossible to see how, in any way, the child could have been taken from the spot she indicated, to the woods, without consuming a considerable period of time—five minutes, at least. To believe that the nurse could have turned away her head for a moment, and then looked around to find the boy gone seemed the sheerest fabric of the imagination; yet the woman, in repeating her story, stuck to it with a grim pertinacity which, it seemed, could come only from the knowledge that she was telling the truth.

Ten days had elapsed since the boy had been kidnapped. It seemed almost useless to search the spot for any evidences of the crime. Yet Duvall began to go over the ground where the nurse testified that she had sat, with the most minute care. Inch by inch, he examined the turf, subjecting almost every blade of grass to a separate examination. The operation required over half an hour, and both Mr. Stapleton and the nurse grew tired of watching him, and strolled about aimlessly.

Hence they did not see him pick up a tiny object from the grass. It was a half-smoked cigarette, dirty and almost falling to pieces from the action of the weather, yet held together by a slender tip of gold.

He placed it carefully within his pocketbook, and rose. "Nothing more to be done here," he called to Mr. Stapleton, and in a moment the three were proceeding toward the waiting automobile.

Upon the return to the house, Mr. Stapleton drew the detective into his library. "Have you discovered anything, Mr. Duvall?" he inquired, making an effort to conceal his almost frantic anxiety.

"I do not know—yet. I may have a clue; but I am not sure."

"What do you think of the woman's story?""It seems impossible to believe it."

"You think, then, that she had a hand in the matter—she and this fellow Valentin?"

"It begins to look like it."

"On what do you base your conclusions, Mr. Duvall? I cannot bring myself to believe that Mary Lanahan is lying, ready as I am to suspect this fellow Valentin."

"First, Mr. Stapleton, on the facts themselves. The boy could not have been taken away without her knowledge. Secondly, upon some minor matters—her error of half an hour, in telling her story, for instance."

"I am sorry, Mr. Duvall, but I cannot believe that you are right. I'd suspect Valentin, at once; but if Mary Lanahan is not telling the truth, then my experience of twenty years in judging human nature has been wasted."

"Yet you yourself heard her admit that she was with Valentin only last Friday, the day she was taken ill."

"Yes. That is true." Mr. Stapleton passed his hand uncertainly across his forehead. "It's too much for me."

"Let me have a word with the nurse, alone, before I go," asked Duvall."Certainly," replied the banker. "I'll send her in to you."

When Mary Lanahan entered the room, the detective went up to her and eyed her sternly. "Was Alphonse Valentin with you at any time, in the Bois, that day?"

"No," replied the girl, steadily.

"Does he smoke gold-tipped cigarettes?" asked Duvall, suddenly.

The effect of this question upon the nurse was startling. She recoiled as though the detective had struck her. "He—he does not smoke at all," she gasped, her face gray with fear.

"Don't lie to me!"

"He does not smoke at all," repeated the girl, almost mechanically, and stood confronting him with a defiant air.

"Very well. That is all." The detective turned from the room and left the house.

He did not, however, go very far. It was rapidly becoming dark. He passed down the street until he judged he was out of sight of the house, then slowly retraced his steps upon the other side, until he had reached a point nearly opposite the small iron gateway which served as the servants' entrance to Mr. Stapleton's house. Here, hidden behind a tree, he watched for perhaps half an hour.

At the expiration of this period, he was rewarded by seeing a young man, evidently an under servant, emerge from the gateway. Duvall watched him as he proceeded down the street, then began to follow him.

The young man seemed in no great hurry, and at the junction of the avenue with the Champs ÉlysÉes, Duvall accosted him, speaking in French.

"Do you want to earn twenty francs, my friend?" he asked pleasantly.

The boy regarded him with a quizzical smile. "Who does not, Monsieur?" he replied.

"Let me see the note you have in your hand."

The boy drew back suddenly, and made as though to thrust the letter into his pocket. "It is impossible, Monsieur," he began.

Duvall took out a gold twenty-franc piece. "I intend to have the letter, my man. If you will give it to me peaceably, here are the twenty francs; if not, I shall be obliged to take it from you by force."

The boy regarded the detective for a moment, as though contemplating flight. Duvall seized him by the collar. "Give me the note," he cried, "or I'll call a gendarme and have you placed under arrest!"

The boy allowed the letter to drop to the pavement, seized the twenty-franc piece, and took to his heels.

Duvall picked it up. As he had expected, it was addressed to Alphonse Valentin, —— Boulevard St. Michel. He had waited, on the chance that Mary Lanahan would lose no time in warning her probable confederate.

The letter gave him the man's address. That was so much accomplished, at least. Then he tore it open, and read the contents. They proved more mystifying than anything that he had yet encountered in this mysterious affair.

"Destroy the cigarettes!" These three words comprised the entire contents of the note.