I have dealt with this particular case at some length partly on account of the vehemence of the controversies which have raged round it and partly because the discrediting of Zöllner's observations has done much to bring the whole idea of the fourth dimension into disfavour and even into ridicule. This, I feel, is unfair and I wish to make it clear that my present advocacy of the claims of the higher space hypothesis is in no way based on the Zöllner experiments.
There are, of course, in the literature of the subject a large number of other cases which are not so obviously unreliable—some, in fact, which are distinctly good.
Dr. S.A. Peters gives an account of an early experiment by Dr. Hare—one of the pioneer investigators—in which two small balls of platinum were transferred to the inside of two hermetically sealed glass tubes. It is not a bad case but is a very old one and the record gives no particulars of any special precautions taken to exclude fraud.
The Milan Committee appointed to investigate the mediumship of Eusapia Palladino failed to obtain any confirmation of Zöllner's experiments, but they seem to have been puzzled by an unaccountable incident where the medium managed to get into, or partially into, a coat while her hands were being held by the Committee. I do not myself regard this case as convincing.
The American Society for Psychical Research recorded some observations with a Mrs. Roberts of New York, who managed to liberate herself from a carefully made and sealed cage which was closed and sealed by members of the investigating committee. I do not know anything at first-hand about the credentials of this case. Dr. Paul Joire quotes it and I suppose, therefore, that he considers it reliable.
The same author also quotes at length a case observed by Dr. Pogorelsky and other Russian investigators with the medium Sambor. In this case a cane chair was passed on to the arms of two of the experimenters whose hands were clasped and bound together. That is to say, whereas to start with the chair was by itself and independent of them it was, at the end of the proceedings, found suspended from their arms by the opening at the back. As the opening was too small for either of them to have wriggled through even if they had wished to do so this was a clear case of apparent penetration of matter by matter.
The evidence in this case seems to be well above the average although it cannot be said to amount to mathematical certainty.
Mr. Gambier Bolton gives a distinctly good case in his book "Psychic Force," p. 65. Under exceptionally favourable conditions he observed the removal of a light table from a sort of tent which he had constructed and very carefully closed and secured. This is one of the best cases I know; it took place in the observer's own room, it was done impromptu, it was well observed in light, and all the objects concerned were the observer's property and not of a kind to admit of prestidigitation. It is difficult to see any way out of it and yet I must confess that I am not wholly satisfied. I feel that in every case there is just something more needed to carry complete conviction and I should very much like to see a good case myself.
Other instances are common. The records of the mediumship of Stainton Moses, for instance, abound with them. But as there were never any test conditions imposed, so far as I am aware, it follows that the question of the genuineness of the phenomena is simply a matter of the integrity of the medium. On this point every reader must be left to form his own opinion. Many authorities have professed the greatest confidence in Moses. Mr. Podmore, on the other hand, presents the suspicious features of the case in a very able criticism in his "Modern Spiritualism." Anyway on a point of such importance as this I do not think it would be right to allow the matter to be settled by any purely moral considerations of the type adduced in the case of Moses.
In general, then, I should say that the phenomena of the apparent penetration of matter by matter are not established with the same degree of certainty which characterises certain other phenomena, and which we ought to demand before accepting them as scientifically proven or utilising them without reserve as a basis for the construction of theories.