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."
"But the test—the test!" cried Vasili.
"The test"—the psychologist turned sternly to face Meyan—"has shown as conclusively and irrefutably as I could hope that this man is not the revolutionist he claims to be, but is, as we suspected might be the case, an agent of the Russian secret police. And not only that! It has shown just as truly, though this fact was at first wholly unsuspected by me, that he—this agent of police who would have betrayed the daughter now and taken her back to Russia to be punished for her share in the previous agitation—is the same agent who, twenty years ago, betrayed the father, Herman Silber, into imprisonment! True name from false I do not know; but this man, who calls himself Meyan now, called himself then Valerian Urth!"
"Valerian Urth!" Eva Silber cried, staggering back into Winton Edwards' arms.
But Meyan made a disdainful gesture with his huge, fat hands. "Bah! You would try to prove such things by your foolish test?"
"Then you will not refuse, of course," Trant demanded sternly, "to show us if there is a knife scar on your chest?"
Even as Meyan would have repeated his denial, Vasili and Munikov leaped from the rear of the room and tore his shirt from his breast. The psychologist rubbed and beat the skin, and the blood rose to the surface, revealing the thin line of an almost invisible and time-effaced scar.
"Our case is proved, I think!" The psychologist turned from the two who stared with hate at the cringing spy, and again faced his clients.
He unlocked the door, and handed the key to Munikov; then, picking up his instrument cases and record sheets, with Miss Silber and his clients he left the room and entered the landlady's sitting room.
CHAPTER V.
AN INTRUSION OF SCIENCE.
WHE N I received Mr. Edwards' letter this morning," Trant said, in answer to the questions that showered upon him, "it was clear to me at once that the advertisement he inclosed depended for its appeal on reminding Eva Silber of some event of prime importance to herself, but also, from the wording employed, of popular or national significance as well. You further told me that October 30th was a special holiday with Miss Silber. That, I found, to be the date of the czar's manifesto of freedom and declaration of amnesty to political prisoners. At once it flashed upon me: Eva Silber was a Russian. The difference between the seventeenth given in the advertisements and the thirtieth—thirteen days—is just the present difference between the old-style calendar used in Russia and ours.
"Before going to the Crerar Library, then, it was clear that we had to do with a Russian revolutionary intrigue," he went on. "At the library I obtained the key to the cipher and translated the advertisement, obtaining the name of Meyan and his address, and also the name and address of Dmitri Vasili, a well-known revolutionary writer. To my surprise, Vasili knew nothing of any revolutionist named Meyan. It was inconceivable that a revolutionary emissary should come to Chicago and he not know of it. It became necessary to find Meyan immediately.
"My first direct clew was the hammering that we heard in this house. It was too much to suppose that in two separate instances this hammering
