We are obliged to act as if there really were a being present who is listening. This being appears to come into existence, and then become non-existent as soon as the experiment is ended. It seems to be created by the medium. Is it an auto-suggestion of hers or of the dynamic ensemble of the experimenters that creates a special force? Is it a doubling of her personality? Is it the condensation of a psychic _milieu_ in the midst of which we live? If we seek to obtain proofs of actual and permanent individuality, and above all of the identity of a particular soul called up in our memory, we never obtain any satisfaction. There lies the mystery. Conclusion: we have here an unknown force of the psychic class, a living force, the life of a moment only. May it not be possible that, in exerting ourselves, we give rise to a detachment of forces which acts exteriorly to our body? But this is not the place, in these first pages, to make hypotheses. The experiment of which I have just spoken was repeated three times running, _in the full light_ of a gas chandelier, and under the same conditions of complete proof in each case. A round table weighing about fourteen pounds is lifted by this unknown force. A table of twenty-five or fifty pounds or more requires a greater number of persons. But they will get no result if one at least among them is not gifted with the mediumistic power. And let me add, on the other hand, that there is in such an experiment so great an expenditure of nervous and muscular energy that such an extraordinary medium as Eusapia, for instance, can obtain scarcely any results six hours, twelve hours, even twenty-four hours, after a seance in which she has so lavishly expended her psychic energy. I will add that quite often the table continues to rise even after the experimenters have ceased to touch it. This is _movement without contact_. This phenomenon of levitation is, to me, absolutely proved, although we cannot explain it. It is like what would happen if one had his hands gloved with loadstone, and, placing them on a table of iron, should lift it from the ground. But the action is not so simple as that: it is a case of psychic activity exterior to ourselves, momentarily in operation.[4] Now how are these levitations and movements produced? How is it that a stick of sealing-wax or a lamp-chimney, when rubbed, attracts bits of paper or elder pith? How is it that a particle of iron grips so firmly to the loadstone when brought near it? How is it that electricity accumulates in the vapor of water, in the molecules of a cloud, until it gives rise to the thunder, the thunderbolt, the lightning flash, and all their formidable results? How is it that the thunderbolt strips the clothes from a man or a woman with its characteristic nonchalance? And (to take a simple instance), without departing from our common and normal condition of life, how is it that we raise our arm?