At that time I had in my employ, and at the head of my establishment, one of the greatest female detectives who ever carried a case to a successful conclusion. She had been in my employ for two years, and had worked up the cases given her in an astonishingly able manner, proving herself a woman of strong, clear discernment. As she takes a prominent part in bringing to light the facts which follow, and in clearing away the mystery that overhung the disappearance of the forty thousand dollars, a short description of her may not prove uninteresting. Two years prior to the time of which I am now writing, I was seated one afternoon in my private office, pondering deeply over some matters, and arranging various plans, when a lady was shown in. She was above the medium height, slender, graceful in her movements, and perfectly self-possessed in her manner. I invited her to take a seat, and then observed that her features, although not what would be called handsome, were of a decidedly intellectual cast. Her eyes were very attractive, being dark blue, and filled with fire. She had a broad, honest face, which would cause one in distress instinctively to select her as a confidante, in whom to confide in time of sorrow, or from whom to seek consolation. She seemed possessed of the masculine attributes of firmness and decision, but to have brought all her faculties under complete control. In a very pleasant tone she introduced herself as Mrs. Kate Warne, stating that she was a widow, and that she had come to inquire whether I would not employ her as a detective. At this time female detectives were unheard of. I told her it was not the custom to employ women as detectives, but asked her what she thought she could do. She replied that she could go and worm out secrets in many places to which it was impossible for male detectives to gain access. She had evidently given the matter much study, and gave many excellent reasons why she could be of service. I finally became convinced that it would be a good idea to employ her. True, it was the first experiment of the sort that had ever been tried; but we live in a progressive age, and in a progressive country. I therefore determined at least to try it, feeling that Mrs. Warne was a splendid subject with whom to begin. I told her to call the next day, and I would consider the matter, and inform her of my decision. The more I thought of it, the more convinced I became that the idea was a good one, and I determined to employ her. At the time appointed she called. I entered into an agreement with her, and soon after gave a case into her charge. She succeeded far beyond my utmost expectations, and I soon found her an invaluable acquisition to my force.