III. Regarding my third proposition—the intensity of the raps is not appreciably affected by distance—I have found that raps could occur as far as three yards away from the medium. The raps given at this distance were as loud and clear as those given close to the medium. This fact would at first seem to imply a difference between the action of psychic force and that of gravitation, light, heat or electricity, all of which act with an energy in inverse proportion to the square of distances. However, such a conclusion would be premature, for secondary centres of accumulation of energy may be formed at a distance from the medium. The term ‘accumulation of energy’ is very vague and may be incorrect, but I dare not give a more precise one, and confine myself to simply stating, that the existence of such centres of accumulation and emission seems indicated, by the manner in which the phenomena are obtained. I have never verified any serious physical effects at a greater distance than that of ten feet. I will add that if the phenomena are not more intense, they are at least more frequent in the immediate neighbourhood of the medium. Such are the observations I have been able to make. It may quite naturally occur to my readers to think I have been the victim of illusion or fraud. This is not the case, however. There is no illusion, simply because nothing permits me to suppose I am the victim of illusion. This assertion is insufficient, I admit: we are bad judges of ourselves. And now I ought to say, that if up to the present I have always clearly distinguished between real facts and subjective impressions, I present, nevertheless, two phenomena which may render my testimony suspect. The first is hypnagogic hallucination, the second coloured audition. The latter is not very decided; sound simply awakens in me the idea of colour, not the visual sensation of colour. My chromo-phonetic scale is _A_, white; _I_, black; _É_, grey; _E_, blue; _on_, green; _er_, _air_, _œil_, orange, etc.[5] This phenomenon was rather marked when I was a child; but, I repeat, the reading of vowels or diphthongs, or the audition of sounds has never awakened a complete sensation of colour; the idea only was evoked. [5] This scale is applicable to the French pronunciation of the vowels in question. On the contrary, hypnagogic illusion is, with me, a decided phenomenon. The illusion is exclusively visual. I have carefully observed this interesting faculty on myself; it appears to me to have its origin in dream. It is a dream begun before sleep has taken complete possession of one. The hallucination disappears as soon as somnolence ceases. It is with extreme difficulty that I am able to retain—even for a second—a hypnagogic picture, when I regain complete consciousness; in spite of all my efforts, the picture fades away or changes form as soon as I fix my attention upon it. I have seldom been able to maintain the illusory impression.