In the first place, we must note that the tonality of raps differs according to the object upon which they resound. It is easy to recognise by the sound if the raps are given on wood, paper, or cloth. This is an interesting demonstration, because it indicates that the sound is produced by the vibrations of the material substance. The material molecules of the object struck are therefore put into movement; they are not, however, always disturbed in the same way, for the tonality of the raps given on the same object is susceptible of great variety. The raps, instead of being sharp and short, may be dull and resemble the muffled sound of impact with some soft body: they may resemble the slight noises made by a mouse, a fret-saw, or the scratching of a finger-nail on wood or cloth: they may affect the most diverse modalities. Their rhythm is as varied as their tonality. One of the most curious facts revealed by the observation of raps, is their relation with what I call the personification. Each personified individuality manifests its presence by special raps. In a series of experiments which have now lasted for more than two years, I have had frequent opportunity of studying raps personifying diverse entities. One of these entities called itself ‘John,’ Eusapia’s control, who has retained a friendly feeling for me, it appears, ever since my first experiments with the Neapolitan medium. ‘John’ manifests by short, sharp raps, so very like the manipulation of the Morse telegraph, that my co-experimenters and I wondered whether we were not actually listening to the usual Morse signals. Unfortunately none of us knew how to recognise letters by rhythm as exercised telegraphists can. A group, of four individualities, who call themselves the ‘Fairies,’ manifest their presence by raps resembling high, clear notes. These personifications are particularly interesting, and, further on, I will have occasion of relating how one of them showed herself to me. The four fairies are fond of mingling in the conversation, approving or disapproving of the ideas expressed by the experimenters. They appear to take considerable interest in the experiments, and I have often noticed that it sufficed—when the raps delayed in making themselves heard—to turn the conversation upon psychical phenomena, their probable explanation, their conditions of realisation, etc., in order to receive approving or disapproving raps at once. Sometimes the raps imitate a burst of laughter—this coincides either with an amusing story related by one of the sitters, or with some mild teasing. Another entity personifies a man for whom I had the deepest affection: these raps are graver in character. This personality seems to have the clairvoyant perspicacity and the kindheartedness of the man I knew. His intervention manifested itself under very curious circumstances, but of too private a nature to be made public. I will cite another personification of more recent appearance.