by Edwin Balmer and William MacHarg

“ There's a red-headed man," one of the crowd cried suddenly, pointing. "Try it on him."
Two enthusiasts at once broke from the group and rushed eagerly to Meyan. He had continued, inattentive through all, to read his newspaper, but now he laid it down. Trant and young Edwards, as he rose and slouched half curiously toward them, could see plainly for the first time his strongly boned, coarsely powerful face, and heavy-lidded eyes, and the grossly muscular strength of his big-framed body. ”

“ Young Winton Edwards, watching as curiously as the others, saw Trant fasten the sphygmograph on the mechanic's arm. and the pencil point commence to trace on the sooty surface a wavy line, the normal record of the mechanic's pulse.
"You see it!" Trant pointed out to the others the record, as it unwound slowly from the drum. "Every thought you have, every feeling, every sensation—taste, touch, smell—changes the beating of your heart and shows upon this little record. ”

“ Every emotion reacts upon the pulse, which strengthens in joy and weakens in sorrow, changes with anger and with despair; and as every slightest variation it undergoes can be detected and registered by the sphygmograph—I felt certain that if I could test the three men together by having Miss Silber tell her father's story aloud, I could determine conclusively by comparison of the records of the two true revolutionists with that of Meyan, whether his sympathies were really with the revolutionist party. ”

“ And though at sight of it no face changed among the three, even Trant's clients could see how one line now suddenly grew flat, with low elevations, irregular and far apart, as the pencil point seemed almost to stop its motion over the smoked paper of the man in the middle, Meyan.
"That is all," said Trant, in a tone of assured triumph, as he unstrapped the sphygmographs from their wrists. "You can speak now, Mr. Edwards."
"Eva!" cried Winton Edwards in wild appeal. "You are not married to this man?" ”

“ Since you and your own are safe, do you become insensible that others now again wait in your place? And those that swing in the wind! Have you forgot? If you remember and are true, communicate. And you can help save them all! ”

“ The psychologist turned to meet young Edwards as he hurried in, and together they went out to join the father at the motor.
"We can do nothing sooner than to-night," Trant said shortly, an expression of keen anxiety on his face. "I must learn more about this man, but my inquiries must be conducted alone. If you will meet me here again at seven o'clock to-night, say at the pawnbroker's shop we passed upon the corner, I hope to be able to solve the mystery of the hammering man, and the influence he is undoubtedly exerting on Miss Silber. ”

“ Then, as Edwards nodded his comprehension, the psychologist turned easily to the man nearest him at the bar—a pallid Lithuanian sweatshop worker.
"I suppose you can stand a lot of that?" Trant nodded at the glass of pungent whisky. "Still—it has its effect on you. Sends your heart action up—quickens your pulse." ”

“ Obviously, it must have been Herman Silber who did the hammering at Eva's home and here in this house. It was obvious, too, that Herman Silber was the 'your own' of the advertisement.
"To test Meyan, whom we found in the saloon, was not difficult," said Trant. "I arranged to have him overhear some one speaking of an arrest at Warsaw, which would at once suggest itself as a hotbed of Russian revolutionists to either a revolutionist or a police agent; but the idea would certainly give positive and very opposite reactions if the man were a true revolutionist or if he were a spy. ”

“ I arranged with Munikov and Vasili to come here with me to-night, and, after Meyan had arrived, they left us here and went to him as representatives of the revolutionary movement to ask his credentials.
"When he could furnish none," Trant went on, "they proposed, and in fact forced him, into this test. It is a dangerous thing to endeavor to pass oneself off as a revolutionist, and it was safer for him to submit to a test than to have his mission frustrated by incurring not only suspicion, but possibly death. ”

“ No," Trant replied. "But to you—and to these gentlemen"—he motioned to the two who had sat at the table with Meyan—"I have to announce the result of my test, for which they are waiting. This elder gentleman is Ivan Munikov, who was forced to leave Russia eight years ago because his pamphlet on 'Inalienable Rights' had incurred the displeasure of the police. This younger man is Dmitri Vasili, who was exiled to Siberia for political offenses at thirteen years of age, but escaped to America. They both are members of the Russian revolutionary organization in Chicago." ”

“ Rooms come not so easy here; we have many people. But now we have another, so to-night she is coming again."
"Does it now seem necessary for us to press this investigation further?" Cuthbert Edwards asked caustically. As he spoke, the sound of measured, heavy blows came to them down the dark stair apparently from the second floor of the building. The elder Edwards cried excitedly and triumphantly: "What is that? Listen! That man—Meyan, if it is Meyan—must be here; for that is the same hammering."
"This is even better luck than we could have expected!" exclaimed the psychologist ”

“ At the bottom of each screen was a circular hole just large enough for a man's arm to go through; and at Trant's command the men put their arms through them. Stooping again swiftly over the instrument cases, Trant took out three sphygmographs.
He rapidly adjusted these on the arms of the three men, and set in motion the revolving drums, against which the pencil points traced their wavy lines on smoked paper. His clients, leaning forward in their interest, could then understand the purpose of the screens, which were designed to hide the pitilessly exact records from the three men. ”

“ Neither he nor the housekeeper, who is not in Eva's confidence, is likely to be able to help us in this matter."
"The man may have slipped out of the house unseen," suggested Trant.
"Quite impossible," Cuthbert Edwards asserted. "Miss Silber lived, in a little house west of Ravenswood. There are very few houses, none within at least a quarter of a mile of her. The ground is flat, and no one could have got away without being seen by me."
"Your story so far is certainly very peculiar," the psychologist commented, "and it gains interest with every detail. ”

“ He introduced me to Munikov, who had been a friend of Silber before his imprisonment, and between them I got the history of Herman Silber and his daughter.
"I explained to Munikov and Vasili that the methods of the psychological laboratory would be as efficacious in picking out a spy among true men as I have many times proved them to be in convicting the criminal. ”

“ Trant descended the stairs, took his instrument case from the motor, and with young Edwards crossed the street quickly to the saloon.
CHAPTER III.
THE CLEVER PENCIL.
A DOZEN idlers leaned against the bar or sat in chairs tilted against the wall. Trant examined these idlers one after another closely. The only man at whom he did not seem to look was one who, as the only red-headed man in the place, must plainly be Meyan. "Red-headed" was the only description they had of him, but meager as it was, with the landlady's statement that he was in the saloon, Trant resolved to test him. ”