I have not been able to discover evidence that Zöllner's mind was really deranged, but he certainly approached the inquiry with a theory of a fourth dimension of space, and was most eager to get his theory confirmed by the experiments. The key to the whole situation is, therefore, lack of sharp control. Slade had been conjuring for years, and was an expert in substitution. He had a purblind audience, and he astutely guided the professor until the conditions of the experiment suited him. He knew beforehand, as a rule, what apparatus Zöllner would use, and he duplicated his wooden rings, thongs, etc. An excellent study of his tricks in detail will be found in Carrington's _Physical Phenomena of Spiritualism_. Sir A. C. Doyle speaks of the shattering of a screen in Slade's presence as an indisputably superhuman feat. But before the séance no one had thought of looking to see if the screen had been taken to pieces and lightly tied together by a black thread which Slade could pull asunder at will! Slade was a very bad selection by Sir A. C. Doyle. No prominent medium was ever so frequently exposed as he. In addition to the exposures I have mentioned, Dr. Hyslop, Mrs. Sidgwick, and other leading Spiritualists riddled his pretensions to supernormal power. In the end he took to drink and died in an asylum. Yet Sir A. C. Doyle assures his followers, in his _Vital Message_, that he never builds on a discredited medium. Let us turn now to Stainton Moses, the snow-white medium. Moses was a neuropathic clergyman who in 1872 left the Church and became a teacher. About the same time he discovered mediumistic powers. He died ultimately of Bright's disease, brought on by drink. His audience, as I said before, consisted only of a few intimate friends who never doubted his saintliness or thought for a moment of fraud. He worked always in the dark, or in a very bad light; and his doings are mainly described by his trustful friend and host, Mrs. Speer. This would dispense any serious student from troubling about his phenomena; but let us see if they throw any light on his character. Mr. Carrington says that the things reported are unbelievable, yet that we cannot think of fraud in connection with Moses. Podmore also tries hard not to accuse him of _conscious_ fraud, and hints that he was irresponsible. The reader may choose to think otherwise.