Were they genuine, these phenomena? I am not sure, but I cannot help wondering how they could have been simulated! There are some distinctions to be made between these appearances, of which I have only described the principal. The luminous hand, which unhooked the bell, was well defined: it was very distinct and one mass of light. I quite understand that suspicion might fall on the medium; he might have covered his own hand with some phosphorescent substance, and, thanks to his height, unhooked the bell himself. Let us try to find out what substance he could have used. We must, I think, put aside the idea of phosphorescent oil. This would have left traces on the medium’s hands and clothes, on the curtains of the cabinet, on the bell, on the wall where the bell was hung. Now there was nothing of the sort. The medium’s hands and garments bore no trace whatsoever of oil. Besides, the light which is given forth by preparations which have phosphorus as their basis, has neither the duration, nor the uniformity of the lights I observed. Is it a preparation with a basis of sulphides of the calcium class? Sulphides, in order to be phosphorescent, ought to be in a dry state. They are usually reduced to a powder, and this powder is pasted on to the substance we wish to render luminous. The appearance of a hand might be given by a glove done over with sulphide of strontium or calcium. But I need not say how difficult it would be to put on this glove. True, the glove could be stuffed with horsehair, dipped in paste and sprinkled over with sulphide in the desired position. The phenomenon which I observed, could then be explained in the following manner: The medium might have moved the luminous glove about with one hand, and unhooked the bell with the other. This is possible, and yet it does not appear to me to explain what I saw. In any case, this explanation ceases to be satisfactory, when we consider the case of the floating lights. I know of no system which allows of imitating the immaterial, fugitive, diaphanous appearance of these curious lights. My chemical knowledge, it is true, is very rudimentary; and one of the young men I speak of is a clever chemist; it may be he knows of a more perfect process than those just mentioned. Nevertheless, it seems to me that a piece of cloth done over with some luminous preparation or other, would not have the aspect of the light which I saw floating about the room. I think it is very difficult to reproduce these vague, ill-defined lights, which are more like a luminous cloud than a phosphorescent material object.