"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.