While I am holding one hand of Eusapia in mine, and one of my astronomical friends, tutor at the Ecole Polytechnique, is holding the other, we are touched, first one and then the other, upon the side and on the shoulders, as if by an invisible hand. The medium usually tries to get together her two hands, held separately by each of us, and by a skilful substitution to make us believe we hold both when she has succeeded in disengaging one. This fraud being well known by us, we act the part of forewarned spectators, and are positive that we have each succeeded in holding her hands apart. The touchings in this experiment seem to proceed from an invisible entity and are rather disagreeable. Those which take place in the immediate vicinity of the medium _could_ be due to fraud; but to some of them this explanation is inapplicable. This is the place to remark that, unfortunately, the extraordinary character of the phenomena is in direct ratio with the absence of light, and we are continually asked by the medium to turn down the gas, almost to the vanishing point: "_Meno luce! meno luce!_" ("Less light, less light"). This, of course, is advantageous to all kinds of fraud. But it is a condition no more obligatory than the others. There is in it no implication of a threat. We can get a large number of mediumistic phenomena with a light strong enough for us to distinguish things with certainty. Still, it is a fact that light is unfavorable to the production of phenomena. This is annoying. Yet we have no right to impose the opposite condition. We have no right to demand of nature conditions which happen to suit us. It would be just as reasonable to try to get a photographic negative without a dark room, or to draw electricity from a rotating machine in the midst of an atmosphere saturated with moisture. Light is a natural agent capable of producing certain effects and of opposing the production of others. This aphorism calls to my mind an anecdote in the life of Daguerre, related in the first edition of this book.