The synchronism between the raps and the movements made by the sitters is very interesting, as it reveals the connection which exists between the organism of the experimenters and the phenomena observed. Richet has already pointed this out. Eusapia Paladino, unconsciously perhaps, employs a process analogous to that which I described a little further back. This synchronism may give, as it has given, equivocal phenomena, and may also give rise to many false accusations of fraud. This is perhaps how Dr. Hodgson comes to attribute certain raps produced by Eusapia Paladino at Cambridge, to the latter striking the table with her head. Of course, I am unable to affirm the reality of the raps heard at Cambridge, seeing I was not present at the sitting of the Sidgwick group. I can but say, that the reading of the few extracts of the _procès verbaux_ of these seances—most incomplete extracts—does not by any means indicate, whether the movement of the Italian medium’s head was the fraudulent physical cause of the rap, or whether this movement was but a synchronous phenomenon. I cannot help thinking that the Cambridge experimenters were either ill-guided, or ill-favoured, for I have obtained raps with Eusapia Paladino in full light, I have obtained them with many other mediums, and it is a minimum phenomenon which they _could_ have, and _ought_ to have obtained, had they experimented in a proper manner. I will discuss these seances more fully further on.[4] Therefore, even in the appreciation of fraud, we must not forget to take into consideration the curious synchronism I am pointing out. [4] See Appendix B. There is another useful observation to make known: namely that raps produced by synchronous movements can be produced by the sitters themselves. In many cases, I have seen experimenters, non-mediums, obtain louder raps than the medium; the presence of a medium, however, is necessary, for, the persons of whom I speak obtain no raps whatever when alone. Here is a subject for study which has not yet been touched upon. Sometimes, in order to obtain raps, it suffices to touch the medium, or to make a slight movement with the hand above the table, or simply to place the palm of the hand gently on the table; this is an excellent way to obtain clear, decided phenomena. The table must be moved away from the medium in such a way that contact is impossible. The observer puts himself beside the medium, takes both his hands in one of his own, and moves the other slowly over the table, or even keeps it quite still above the table. Nothing is more demonstrative than this experiment. Let us remember I am speaking of experiments made in broad daylight.