Again, in his Reality of Psychic Phenomena, he says:
"I took the electroscope to the table in the corner; then placed it in the circle near the medium. I asked the operators to touch the disc of the instrument very gently. They did this almost at once, the 'touching' consisting of a metallic scraping upon the brass disc, quite audible, similar in type to the imitation of the floor being rubbed with sand paper, a phenomenon I quite often observed.
"Result:—On examination, the electroscope was found to be completely discharged!
"I took the electroscope to the table in the corner of the room and tried to recharge it, but found I was unable to do so even after repeated trials. Accordingly I asked the 'operators' to put back into the body of the medium the matter they had taken out (for the production of the sledge-hammer blows) and to give a few raps when they had done so. In a minute or two some very light raps were given, and when I asked if the process was complete I received no raps in reply at all, which seemed to indicate to me that all the matter used for rapping had been returned to the medium. At any rate, I found that I could now charge the electroscope; which done, I placed it on the floor as before within the circle, and asked that the disc should be touched lightly. After a little time, there was the metallic scraping as before, and on examination the electroscope was found to be completely discharged."
It will be at once apparent to the reader that two problems confront the investigator, when once he is called upon to solve such problems as the above: (1) the physical miracle itself; and (2) the nature of the intelligence, lying behind and directing or controlling the manifestations. This latter is purely a psychological question, which, immensely important as it is intrinsically, does not enter into the physical problem. It need only be said that this is the baffling question in psychical investigation, and the most puzzling. Whether it be an independent "spirit," as it claims to be; or the subconsciousness of the medium; or whether it is a sort of compound consciousness, made up of the collected minds of those forming the circle at the time; or whether some other interpretation is open to us—this is all a moot question, which is referred to here, merely to draw attention to the fact of its existence.
It will be at once apparent to the reader, also, that physical and electrical apparatus have played an important part in such investigations, in the past, and are certainly destined to occupy a far more important place in the future. These curious phenomena—like all others in our world—depend upon invisible forces or energies for their production. Those interested in electricity should realize, more than all others, the power of the invisible; and the fact that the invisible is the real. Anything that we see consists merely in a bundle of "phenomena"—of effects. The real cause is always behind, and is always invisible.
There is nothing inherently absurd or impossible, therefore, in these odd manifestations,—however bizarre and unusual they appear to us at first sight. An unusual combination of circumstances might bring them about. Stones do not ordinarily fall out of the air; yet at times they do (meteors). Water does not usually rise above its own level, yet it can be made to do so. The curious freaks of lightning are well known. There is nothing inherently impossible, therefore, in supposing that a table can be "levitated" into the air, under unusual conditions; it is simply the manifestation of an unknown energy—of which, doubtless, there are many. We can manipulate and control the electric current; but we do not know yet precisely what it is. Similarly, we can study the effects of many of these curious biological forces, without understanding their true nature. Above all, it behooves us to keep an open mind, and not to cry "impossible," just because we have never seen such facts, or because they appear to us innately improbable.
Here, as elsewhere, we depend upon hidden and unknown energies. Could we but find an energy common to the two worlds—the spiritual world and the material world—we should have here a means of direct communication, possibly by instrumental means. Delicate physical and electrical apparatus may be the means, after all, by which such communication will ultimately be established! At all events, when subtle causes and forces are in operation (as they doubtless are during a séance) it is only natural to suppose that instruments, far more delicate than our senses, should be the logical method of detecting them, and, as yet, such experiments have rarely been attempted.
When we take into consideration, finally, the electrical theory of the nature of matter; when we remember the many striking analogies between electricity and the life-force; when we remember that the science of electricity is yet in its infancy, it should hold out to us the hope that, here, we may find a solution of many of these obscure problems, and that further investigations in the field of electricity may serve to explain to us many of these unknown and mysterious secrets of our inner nature, and the still more mysterious secrets of the séance-room. No more interesting and profitable researches could be attempted than those which endeavour to establish a connection between known and unknown phenomena; between physical and electrical manifestations, on the one hand, and these curious "psychical" phenomena, on the other. The crying need of the day is a "Psychical Laboratory," wherein such experiments as these could be conducted. It is my sincere hope that, some day, I may assist in the foundation of such a laboratory.