And to Mrs. Hart's apartment he at once proceeded, and, by dint of his easy assurance, soon succeeded in leading her, as he had already done the rest, into a discussion of the one topic for which he had an interest. He had not time, however, to glean much from her, for, just as she was making the admission that Mr. Mansell had not been home at the time of the murder, a knock was heard at the door, and, with an affable bow and a short, quick stare of surprise at Mr. Byrd, the ubiquitous Mr. Brown stepped in and took a seat on the sofa, with every appearance of intending to make a call. At this third check, Mr. Byrd was more than annoyed. Rising, however, with the most amiable courtesy, he bowed his acknowledgments to the landlady, and, without heeding her pressing invitation to remain and make the acquaintance of Mr. Brown, left the room and betook himself back to the parlors. He was just one minute too late. The last of the boarders had gone up-stairs, and only an empty room met his eyes. He at once ascended to his own apartment. It was on the fourth floor. There were many other rooms on this floor, and for a moment he could not remember which was his own door. At last, however, he felt sure it was the third one from the stairs, and, going to it, gave a short knock in case of mistake, and, hearing no reply, opened it and went in. The first glance assured him that his recollection had played him false, and that he was in the wrong room. The second, that he was in that of Mr. Mansell. The sight of the small model of a delicate and intricate machine that stood in full view on a table before him would have been sufficient assurance of this fact, even if the inventor himself had been absent. But he was there. Seated at a table, with his back to the door, and his head bowed forward on his arms, he presented such a picture of misery or despair, that Mr. Byrd felt his sympathies touched in spite of himself, and hastily stumbling backward, was about to confusedly withdraw, when a doubt struck him as to the condition of the deathly, still, and somewhat pallid figure before him, and, stepping hurriedly forward, he spoke the young man's name, and, failing to elicit a response, laid his hand on his shoulder, with an apology for disturbing him, and an inquiry as to how he felt. The touch acted where the voice had failed. Leaping from his partly recumbent position, Craik Mansell faced the intruder with indignant inquiry written in every line of his white and determined face. "To what do I owe this intrusion?" he cried, his nostrils expanding and contracting with an anger that proved the violence of his nature when aroused.