(_d_) Finally, the characteristic fatigue which follows successful seances, fatigue similar to that which is felt after prolonged or violent exercise, that is to say, exercise necessitating a considerable expenditure of nervous force. In a book, in which I am striving to exclude all manner of theory, treating, moreover, of a subject where theoretical hypotheses are premature, I cannot enlarge any further upon these considerations. I must content myself with pointing them out to the attention of those, who may wish to experiment in their turn. Telekinetic movements are more difficult to simulate than levitations of the table with contact. By operating in daylight, as I have done, and with non-professional mediums, there is every kind of guarantee. Besides, it is very difficult for even a professional medium to trick telekinetic phenomena in full light; he must be a terribly bad observer, who lets himself be taken in under test conditions of light. The slightest link between the medium and the object in movement is easily perceptible, and it is very easy to make sure, that no such link exists. I recommend experimenters to force themselves to direct the phenomena towards movements without contact. I do not advise them even to begin with levitations with contact, for it is a manifestation which is easily simulated; and I advise persons who are not accustomed to seances, and who are not familiar with fraudulent processes, to seek for telekinetic phenomena only. They are longer in coming, and more difficult to obtain; but their demonstration will make it well worth while taking pains to realise them, and spending time to wait for them. When we work in good light, when we can pass our hands in every direction round the article of experimentation, when we operate with articles not belonging to the medium, which have not been in his possession or handled by him, the hypothesis of fraud is inadmissible. I do not speak of the honourability and good faith of the medium: these are important elements of appreciation. But my principle is not to let these considerations have any weight, when judging of a paranormal fact. For, if the observation is to have any serious value, every one ought to be able to verify the conditions, under which that observation is made. To sum up, the observations, I have so often made with diverse mediums, have thoroughly convinced me of the reality of movements without contact. I believe I have verified a connection between them and the organism of the experimenters. There is a _synergy_ between their movements and their muscular contractions and the forthcoming paranormal movements. I have already spoken of this coincidence in the chapter on ‘Raps.’