At last the telephone rang and Carton answered it eagerly. As he did so, he quickly motioned to us to go to the outside office where we, too, could listen on extensions.

"Yes, this is Mr. Carton," we heard him say.

"This is the editor of the Wall Street Record," came back the reply in a tone that showed no hesitation or compunction if it was lying. "I suppose you have heard the rumours that are current downtown that Hartley Langhorne and the people associated with him have gone broke in the pool they formed to get control of the public utilities that would put them in a position to capture the city betterment contracts?"

"No—I hadn't heard it," answered Carton, with difficulty restraining himself from quizzing the informant about himself. Kennedy was motioning to him that that was enough. "I'm sure I can't express any opinion at all for publication on the subject," he concluded brusquely, jamming down the receiver on the hook before his interlocutor had a chance to ask another question.

The bell continued to ring, but Craig seized the receiver off its hook again and called back, "Mr. Carton has gone for the day," hanging it up again with a bang.

"Call up the Record now," advised Craig, disconnecting the recording instrument he had brought. "See what the editor has to say."

"This is the District Attorney's office," said Carton a moment later when he got the number. "You just called me."

"I called you?" asked the editor, non-plussed.

"About a rumour current in Wall Street."

"Rumour? No, sir. It must be some mistake."

"I guess so. Sorry to have troubled you. Good-bye."

Carton looked from one to the other of us. "You see," he said in disgust, "there it is again. That's the sort of thing that has been going on all day. How do I know what that fellow is doing now—perhaps using my name?"

I had no answer to his implied query as to who was the "wolf" and what he might be up to. As for Kennedy, while he showed plainly that he had his suspicions which he expected to confirm absolutely, he did not care to say anything about them yet.

"Two can play at 'wolf,'" he said quietly, calling up the headquarters of Dorgan's organization.

I wondered what he would say, but was disappointed to find that it was a merely trivial conversation about some inconsequential thing, as though Kennedy had merely wished to get in touch with the "Silent Boss." Next he called up the sanitarium to which Murtha had been committed, and after posing as Murtha's personal physician managed to have the rules relaxed to the extent of exchanging a few sentences with him.

"How did he seem—irrational?" asked Carton with interest, for I don't think the District Attorney had complete confidence in the commonly announced cause of Murtha's enforced retirement.

Kennedy shook his head doubtfully. "Sounded pretty far gone," was all he said, turning over the pages of the telephone book as he looked for another number.

This time it was Kahn whom he called up, and he had some difficulty locating him, for Kahn had two offices and was busily engaged in preparing a defence to the charges preferred against him for the jury fixing episode.

Among others whom he called up was Langhorne, and the conversation with him was as perfunctory as possible, consisting merely in repeating his name, followed by an apology from Kennedy for "calling the wrong number."

In each case, Craig was careful to have his little recording instrument working, taking down every word that was uttered and when he had finished he detached it, looking at the cylinder with unconcealed satisfaction.

"I'm going up to the laboratory again," he announced, as Carton looked at him inquiringly. "The investigation that I have in mind will take time, but I shall hurry it along as fast as I possibly can. I don't want any question about the accuracy of my conclusions."

We left Carton, who promised to meet us late in the afternoon at the laboratory, and started uptown. Instead, however, of going up directly, Craig telephoned first to Clare Kendall to shadow Mrs. Ogleby.

The rest of the day he spent in making microphotographs of the phonograph cylinder and studying them very attentively under his high-powered lens.

Toward the close of the afternoon the first report of Miss Kendall, who had been "trailing" Mrs. Ogleby, came in. We were not surprised to learn that she had met Langhorne in the Futurist Tea Room in the middle of the afternoon and that they had talked long and earnestly. What did surprise us, though, was her suspicion that she had crossed the trail of someone else who was shadowing Mrs. Ogleby.

Kennedy made no comment, though I could see that he was vitally interested. What was the significance of the added mystery? Someone else had an interest in watching her movements. At once I thought of Dorgan. Could he have known of the intimacy of his guest at the Gastron dinner with Langhorne, rather than with Murtha, with whom she had gone? Suddenly another explanation occurred to me. What was more likely than that Martin Ogleby should have heard of his wife's escapade? He would certainly learn now to his surprise of her meeting with Langhorne. What would happen then?

Kennedy had about finished with his microphotographic work and was checking it over to satisfy himself of the results, when Carton, as he had promised, dropped in on us.

"What are you doing now?" he asked curiously, looking at the prints and paraphernalia scattered about. "By the way, I've been inquiring into the commitment of Murtha to that sanitarium for the insane. On the surface it all seems perfectly regular. It appears that, unknown even to many of his most intimate friends, he has been suffering from a complication of diseases, the result of his high life, and they have at last affected his brain, as they were bound to do in time. Still, I don't like his 'next friends' in the case. One is his personal physician—I don't know much about him. But Dorgan is one of the others."

"We'll have to look into it," agreed Kennedy. "Meanwhile, would you like to know who your 'wolf' is that has been spreading rumours about broadcast?"

"I would indeed," exclaimed Carton eagerly. "You were right about the statement I issued. It had no more effect than so many unspoken words. The fellow has kept right on. He even had the nerve to call up Miss Ashton in my name and try to find out whether she had any trace of the missing Betty Blackwell. How do you suppose they found out that she was interested?"

"Not a very difficult thing," replied Kennedy. "Miss Ashton must have told several organizations, and the grafters always watch such societies pretty closely. What did she say?"

"Nothing," answered Carton. "I had thought that they might try something of the sort and fortunately I warned her to disregard any telephone messages unless they came certainly from me. We agreed on a little secret formula, a sort of password, to be used, and I flatter myself that the 'wolf' won't be able to accomplish much in that direction. You say you have discovered a clue? How did you get it?"

Kennedy picked up one of the microphotographs which showed an enlargement of the marks on the phonograph cylinder. He showed it to us and we gazed curiously at the enigmatic markings, greatly magnified. To me, it looked like a collection of series of lines. By close scrutiny I was able to make out that the lines were wavy and more or less continuous, being made up of collections of finer lines,—lines within lines, as it were.

An analysis of their composition showed that the centre of larger lines was composed of three continuous series of markings which looked, under the lens, for all the world like the impressions of an endless straight series of molar teeth. Flanking these three tooth-like impressions were other lines—varying in width and in number—I should say, about four, both above and below the tooth-like impressions. When highly magnified one could distinguish roughly parallel parts of what at even a low magnification looked like a single line.

"I have been studying voice analysis lately," explained Kennedy, "particularly with reference to the singing voice. Mr. Edison has made thousands and thousands of studies of voices to determine which are scientifically perfect for singing. That side of it did not interest me particularly. I have been seeking to use the discovery rather for detective purposes."

He paused and with a fine needle traced out some of the lines on the photographs before us.

"That," he went on, "is a highly magnified photograph of a minute section of the phonographic record of the voice that called you up, Carton, as editor of the Wall Street Record. The upper and lower lines, with long regular waves, are formed by a voice with no overtones. Those three broader lines in the middle, with rhythmic ripples, show the overtones."

Carton and I followed, fascinated by the minuteness of his investigation and knowledge.

"You see," he explained, "when a voice or a passage of music sounds or is sung before a phonograph, its modulations received upon the diaphragm are written by the needle point upon the surface of the cylinder or disc in a series of fine waving or zig-zag lines of infinitely varying depth and breadth.

"Close familiarity with such records for about forty years has taught Mr. Edison the precise meaning of each slightest variation in the lines. I have taken up and elaborated his idea. By examining them under the microscope one can analyze each tone with mathematical accuracy and can almost hear it—just as a musician reading the score of a song can almost hear the notes."

"Wonderful," ejaculated Carton. "And you mean to say that in that way you can actually identify a voice?"

Kennedy nodded. "By examining the records in the laboratory, looking them over under a microscope—yes. I can count the overtones, say, in a singing voice, and it is on the overtones that the richness depends. I can recognize a voice—mathematically. In short," Craig concluded enthusiastically, "it is what you might call the Bertillon measurement, the finger-print, the portrait parle of the human voice!"

Incredible as it seemed, we were forced to believe, for there on the table lay the graphic evidence which he had just so painstakingly interpreted.

"Who was it?" asked Carton breathlessly.

Kennedy picked up another microphotograph. "That is the record I took of one of the calls I made—merely for the purpose of obtaining samples of voices to compare with this of the impersonator. The two agree in every essential detail and none of the others could be confounded by an expert who studied them. Your 'wolf' was your old friend Kahn!"

"Fighting back at me by his usual underhand methods," exclaimed Carton in profound disgust.

"Or else trying himself to get control of the Black Book," added Kennedy. "If you will stop to think a moment, his shafts have been levelled quite as much at discrediting Langhorne as yourself. He might hope to kill two birds with one stone—and incidentally save himself."

"You mean that he wants to lay a foundation now for questioning the accuracy of the Black Book if it ever comes to light?"

"Perhaps," assented Kennedy carefully.

"Surely we should take some steps to protect ourselves from his impostures," hastened Carton.

"I have no objections to your calling him up and telling him that we know what he is up to and can trace it to him—provided you don't tell him how we did it—yet."

Carton had seized the telephone and was hastily calling every place in which Kahn was likely to be. He was not at either of his offices, nor at Farrell's, but at each place successively Carton left a message which told the story and which he could hardly fail to receive soon.

As Carton finished, Kennedy seemed to be emerging from a brown study.
He rose slowly and put on his hat.

"Your story about Murtha's commitment interests me," he remarked, "particularly since you mentioned Dorgan's name in connection with it. I've been thinking about Murtha myself a good deal since I heard about his condition. I want to see him myself."

Carton hesitated a minute. "I can break an engagement I had to speak to-night," he said. "Yes, I'll go with you. It's more important to look to the foundations than to the building just now."

A few minutes later we were all on our way in a touring car to the private sanitarium up in Westchester, where it had been announced that Murtha had been taken.

I had apprehended that we would have a great deal of difficulty either in getting admitted at all or in seeing Murtha himself. We arrived at the sanitarium, a large building enclosed by a high brick wall, and evidently once a fine country estate, at just about dusk. To my surprise, as we stopped at the entrance, we had no difficulty in being admitted.

For a moment, as we waited in the richly furnished reception room, I listened to the sounds that issued from other parts of the building. Something was clearly afoot, for things were in a state of disorder. I had not an extensive acquaintance with asylums for the care and treatment of the insane, but the atmosphere of excitement which palpably pervaded the air was not what one would have expected. I began to think of Poe's Dr. Tarr and Professor Fether, and wonder whether there might not have been a revolution in the place and the patients have taken charge of their keepers.

At last one of the attendants passed the door. No one had paid any attention to us since our admission and this man, too, was going to pass us without notice.

"I beg your pardon," interrupted Kennedy, who had heard his footsteps approaching and had placed himself in the hallway so that the attendant could not pass, "but we have called to see Mr. Murtha."

The attendant eyed us curiously. I expected him to say that it was against the rules, or to question our right to see the patient.

"I'm afraid you're too late," he said briefly, instead.

"Too late?" queried Kennedy sharply. "What do you mean?"

The man answered promptly as if that were the quickest way to get back to his own errand.

"Mr. Murtha escaped from his keepers this evening, just after dinner, and there is no trace of him."