Truth to tell, these supernatural manifestations seem less marvelous and less fantastic than they did some centuries ago; and we are at first a little disappointed. One would think that even the mysterious has its ups and downs and remains subject to the caprices of some strange extra mundane fashion; or perhaps, to be more exact, it is evident that the majority of those legendary miracles could not withstand the rigorous scrutiny of our day. Those which emerge triumphant from the test and defy our less credulous and more penetrating vision are all the more worthy of holding our attention. They are not the last survivals of the riddle, for this continues to exist in its entirety and grows greater in proportion as we throw light upon it; but we can perhaps see in them the supreme or else the first efforts of a force which does not appear to reside wholly in our sphere. They suggest blows struck from without by an Unknown even more unknown than that which we think we know, an Unknown which is not that of the universe, not that which we have gradually made into an inoffensive and amiable Unknown, even as we have made the universe a son of province of the earth, but a stranger arriving from another world, an unexpected visitor who comes in a rather sinister way to trouble the comfortable quiet in which we were slumbering, rocked by the firm and watchful hand of orthodox science. 4 Let us first be content to enumerate them. We shall find that we have table-turning, with its raps; the movements and transportations of inanimate objects without contact; luminous phenomena; lucidite, or clairvoyance; veridical apparitions or hallucinations; haunted houses; bilocations and so forth; communications with the dead; the divining-rod; the miraculous cures of Lourdes and elsewhere; fluidic asepsis; and lastly the famous thinking animals of Elberfeld and Mannheim. These, if I be not mistaken, after eliminating all that is in, sufficiently attested, constitute the residue or caput mortuum of this latter-day miracle. Everybody has heard of table-turning, which may be called the A B C of occult science. It is so common and so easily produced that the Society for Psychical Research has not thought it necessary to devote special attention to the subject. I need hardly add that we must take count only of movements or "raps" obtained without the hands touching the table, so as to remove every possibility of fraud or unconscious complicity. To obtain these movements it is enough, but it is also indispensable that those who form the "chain" should include a person endowed with mediumistic faculties. I repeat, the experiment is within the reach of any one who cares to try it under the requisite conditions; and it is as incontestable as the polarization of light or as crystallization by means of electric currents.