Such are the experiments of Sir William Crookes. I have restricted myself to relating his own personal observations, as set forth by himself. The story of Katie King is truly one of the most mysterious, the most incredible, to be found in the whole history of Spiritualistic research, and is at the same time, one of the cases that have been most scrupulously studied by the experimental method, including photography. The medium, Miss Florence Cook, married in 1874 Mr. Elgie Corner, and, from that time on, her contributions to psychical research almost ceased. I have several times been assured that she also had been caught in the very act of cheating. (Always that feminine hysteria!) But the investigations of Crookes were conducted with such care and competence, that it is very difficult to refuse our credence. Besides, this scientist was not the only one to study the mediumship of Florence Cook. Among other works that may be consulted on this subject is one containing a large number of proofs and testimonies, as well as several photographs (alluded to above).[68] These recorded cases, or testimonies, form a collection of records, the study of which is most instructive. The study of the great chemist surpass the rest, to be sure, but it does not diminish the intrinsic value of the others. All the observations agree and mutually confirm each other. As to the explanation of the phenomena, Crookes thinks that we cannot discover it. Was this apparition what it claimed to be? There is nothing to prove it. Might it not be a _double_ of the medium, a product of her psychic force? The learned chemist did not change his opinion (as has been claimed) about the authenticity of the phenomena studied by him. In an address delivered at a meeting of the British Association for the Advancement of Science, held at Bristol in 1898, and of which he was President, he expressed himself as follows: No incident in my scientific career is more widely known than the part I took many years ago in certain psychic researches. Thirty years have passed since I published an account of experiments tending to show that outside our scientific knowledge there exists a Force exercised by intelligence differing from the ordinary intelligence common to mortals. This fact in my life is, of course, well understood by those who honored me with the invitation to become your President. Perhaps among my audience some may feel curious as to whether I shall speak out or be silent. I elect to speak, although briefly. To enter at length on a still debatable subject would be to insist on a topic which,--as Wallace, Lodge and Barrett have already shown,--though not unfitted for discussion at these meetings, does not yet enlist the interest of the majority of my scientific brethren. To ignore the subject would be an act of cowardice, an act of cowardice I feel no temptation to commit.