It gives itself out to be the astronomer, Chappe d’Auteroche, and has related most accurately the details of his life and death in California. As a biographical notice concerning this learned man appears in several dictionaries, notably in Larousse, it is impossible to affirm that the irruption of this personification is supernormal. The raps which announce his presence are dull-sounding, and are given with a certain amount of force. In conclusion, light precipitated raps, weak but abundant, are the signals of certain personifications which we might call mar-joys—troublesome guests, whose unwelcome intervention spoils the experience. Let it not be forgotten, that if I point out the connection existing between the personifications and the raps, it does not follow that I accept the reality of those personifications. I am making a statement, and I fill in all the details, so that experimenters, tempted to resume my observations, may know exactly what I have observed. So far, the personifications have not convinced me of their identity. It is true I act somewhat indifferently the rôle of listener to their fatiguing and rambling conversations, and that I do all I can to bring them back to material phenomena, so much more important to me in that they are so much easier to verify. Were I, however, not to point out the rôle which the raps play in relation to the personification, I would be omitting one of their most significant features, and would not be giving their exact physiognomy. They manifest themselves, then, as the expression of a will and activity distinct from those of the observers. Such is the _appearance_ of the phenomenon. A curious fact is the result—not only do the raps reveal themselves as the productions of intelligent action, they also manifest intelligence in response to any particular rhythm or code which might be demanded. Often the different raps reply to one another; and one of the most interesting experiences one can have is to hear these raps clear and resonant, or soft and muffled, sounding simultaneously on the floor, table, furniture, etc. I have had exceptionally good opportunities of studying very closely this curious phenomenon of raps, and I think I have arrived at some conclusions. The first and most certain is their undoubtedly close connection with the muscular movements of the sitters. I may sum up my observations on this point in the three following propositions:— 1. All muscular movements, however slight, are generally followed by a rap. 2. The intensity of the raps does not strike me as being in proportion with the movement made. 3. The intensity of the raps does not seem to me to vary proportionately according to their distance from the medium. The following are the facts upon which I build my conclusions:—