By this time Murdock had passed into his study, so that Sturgis found himself alone in the hall. He was glad of a short respite during which he might collect his thoughts; for, having been taken by surprise, he had not had time to select a plausible topic for the interview which he had solicited from Murdock. Not knowing that the house was that of the chemist, his sole object had been to gain admittance, so that he might be able to observe the Manhattan Chemical Company's offices from the rear, and if possible to ascertain how Chatham had managed to give the detectives the slip the first time he appeared to them.

Now that he was in the house the reporter was confronted with the necessity of explaining his presence there without betraying his true purpose. This would not have been a difficult matter had the inmates of the house been total strangers; but he felt that it would be by no means so easy to offer an explanation which would be satisfactory to a man of Murdock's keen perception. And Murdock was the last person to whom he would have confided the true reason of his visit; not only because the chemist, as his opponent in the wager concerning the Knickerbocker Bank Mystery, was interested in thwarting rather than in aiding his investigation, but chiefly because he felt a strong instinctive distrust of the man.

As these thoughts were passing through the reporter's mind, he slowly paced the long hall, back and forth, with his hands behind his back. In so doing, he passed a door which was slightly ajar and caught a glimpse of long rows of book-shelves loaded with beautifully bound editions. The place was evidently the library. It occurred to him that a library is a public room and that he would be more comfortable in there than in the hall.

He pushed open the door and looked in. The room was empty. He entered.

The library occupied a space between the parlor and the rear room into which Murdock had entered, and it was separated from each of these rooms by folding-doors over which hung heavy portières.

Sturgis was a lover of books; his interest was at once aroused in the collection before him. It was admirably selected from the standpoint of a philosopher and a man of science. Every department of history, of philosophy and of science had its section, in which the volumes were classified and arranged with intelligent care. But curiously enough, poetry and art were but meagerly represented.

One section especially attracted Sturgis's attention. It was devoted entirely to the history of crime in all its phases and in all ages. Criminal statistics, criminal jurisprudence and the psychology of crime, as well as the biographies of all the noted criminals of ancient and modern times, were completely represented. Almost the only works of fiction in the collection were in this section, and included every book imaginable concerning criminals and their deeds. Many rare and curious volumes were there—some of them so rare that they could be found in only a few of the great libraries of the world.

Here Sturgis was in his element. He had himself collected a valuable library on the subjects kindred to his profession; but here were books many of which none but a Crœsus could ever hope to own. He was soon absorbed in an examination of some rare volumes which he had often longed to possess.

While thus engaged, he became aware of the murmur of voices from the rear room. As the words spoken could not be distinguished, he paid no special attention to them; but, instinctively, he noted that one of the voices flowed in the calm, even tones so characteristic of Murdock's speech, while the other, whose timbre and modulations were unknown to him, betrayed the repressed excitement of the speaker.

It soon became evident that Murdock's interlocutor was fast losing control of himself; for he gradually pitched his voice in a higher key, until occasional words began to reach Sturgis's ears. The reporter was not the man to wantonly play the part of eavesdropper; therefore, although the isolated words which reached him brought no connected sense, he judged that it was time to move out of earshot of the conversation to which he was becoming an involuntary listener. Replacing upon its shelf the book which he had been examining, he started toward the hall door. As he did so, he heard the now thoroughly excited individual exclaim in loud tones: